See the finding. Know what matters.

Pneumoperitoneum

Free intraperitoneal air suggests a perforated hollow viscus; with peritonitis or sepsis, begin resuscitation and antibiotics and obtain urgent surgical source control.

Necrotizing enterocolitis

Necrotizing enterocolitis: pneumatosis intestinalis (intramural gas) in a preterm infant — NPO, antibiotics; free air means surgery.

Small bowel obstruction

Small-bowel obstruction: dilated loops with stacked air-fluid levels and a paucity of colonic gas — NG decompression; surgery for strangulation.

Sigmoid volvulus

Sigmoid volvulus: coffee-bean loop pointing to the right upper quadrant — sigmoidoscopic detorsion, then elective sigmoidectomy.

Toxic megacolon

Toxic megacolon is nonobstructive colonic dilation with systemic toxicity. Avoid full colonoscopy and antimotility drugs; obtain urgent surgical assessment and cause-specific treatment. In acute severe ulcerative colitis, toxic megacolon itself is an indication for colectomy.

CTA2 files

Aortic dissection on CTA

CTA can show an intimal flap dividing the true and false lumens. Stanford type A involves the ascending aorta and changes the urgent management pathway.

Acute appendicitis

Appendicitis on CT: dilated appendix >6 mm with wall enhancement and fat stranding — ultrasound first in children and pregnancy.

Saddle embolus straddling the main pulmonary artery bifurcation with RV:LV diameter…

Platelets fall >50% on heparin days 5–10 + new clot → HIT: stop all heparin, start argatroban; no warfarin yet. Exception: heparin within prior 100 days → rapid onset.

Non-contrast CT showing a hyperdense calculus impacted in the proximal ureter with…

Obstructing stone with infection or sepsis requires urgent stent or nephrostomy drainage plus antibiotics. Uncomplicated small stones may be observed with analgesia; alpha-blocker benefit is greatest for selected distal ureteral stones.

Sigmoid diverticulitis

Sigmoid diverticulitis on CT: wall thickening with pericolic fat stranding — abscess >3 cm gets percutaneous drainage; colonoscopy after 6–8 weeks.

Epidural hematoma CT

Epidural hematoma is typically biconvex and limited by sutures. Obtain urgent neurosurgical evaluation; large or symptomatic lesions require evacuation, while selected small stable lesions can be observed.

Intracerebral hemorrhage CT

Acute intracerebral hemorrhage requires prompt anticoagulant reversal when indicated and specialist care. In mild to moderate spontaneous ICH with presenting SBP 150–220 mmHg, target about 140 and maintain 130–150; individualize severe cases.

MCA stroke CT

MCA infarct: hyperdense MCA sign early, then wedge-shaped hypodensity — CT is to exclude bleeding before tPA, not to see the infarct.

CT2 files

Acute pancreatitis CT

Diagnose acute pancreatitis clinically and biochemically. Use contrast CT when the diagnosis is uncertain or complications are suspected; a nonenhancing area suggests necrosis.

Pulmonary embolism

CT pulmonary angiography can demonstrate pulmonary arterial filling defects. Anticoagulate when appropriate and assess clinical severity; PE with shock requires urgent reperfusion assessment, with systemic thrombolysis or an alternative selected according to bleeding risk and availability.

CT2 files

Ureteral stone CT

Small uncomplicated ureteral stones often pass with analgesia and observation; alpha-blockers chiefly benefit distal stones 5–10 mm. Infected obstruction or anuria requires urgent decompression; size alone does not.

CT4 files

Subarachnoid hemorrhage CT

Suspected SAH requires urgent noncontrast CT. If presentation is beyond six hours or there is a new neurologic deficit and CT is negative, perform lumbar puncture; confirmed aneurysmal SAH requires nimodipine and aneurysm management.

Subdural hematoma CT

Subdural hematoma: crescent-shaped collection that crosses sutures — bridging veins; elderly, anticoagulated, alcohol-use patients.

Traumatic hemothorax

Traumatic hemothorax: chest tube; >1,500 mL at insertion or >200 mL/h for 2–4 h means thoracotomy.

Lobar pneumonia

Lobar consolidation with air bronchograms supports an air-space process; with an infectious presentation, treat pneumonia according to severity and risk factors. The radiograph alone does not establish pneumococcal infection.

Pneumothorax

Pneumothorax produces a visceral pleural line with absent peripheral lung markings. Suspected tension physiology with hemodynamic instability or severe respiratory compromise requires immediate decompression without waiting for imaging.

Atrial fibrillation

Atrial fibrillation: irregularly irregular RR intervals with no discernible P waves.

Atrial flutter

Atrial flutter 2:1: sawtooth flutter waves in the inferior leads at a ventricular rate near 150/min.

Mobitz II block

Mobitz type II: fixed PR with unpredictable dropped beats — infranodal; pacemaker.

Mobitz I block

Mobitz I shows progressive PR prolongation before a nonconducted P wave; asymptomatic AV-nodal block often needs observation, while symptomatic or unstable bradycardia requires treatment.

Complete heart block

Third-degree AV block: atrial and ventricular rhythms march independently — pacemaker.

Irregularly irregular wide-complex tachycardia at a rate of approximately 190-220/min,…

Irregular wide-complex tachycardia with varying QRS → pre-excited AF: procainamide or ibutilide if stable. Exception: unstable → synchronized cardioversion; never AV nodal blockers.

12-lead ECG with tall, narrow-based, symmetric peaked T waves in V2–V5, flattened P…

Hypotension with hyponatremia, hypoglycemia, and possible hyperkalemia suggests adrenal crisis: give IV hydrocortisone and isotonic fluids promptly. Normal potassium does not exclude primary adrenal insufficiency.

Regular wide-complex tachycardia (QRS >120 ms) at a rate of 170/min with AV…

Treat wide-complex tachycardia of uncertain origin as VT. Avoid verapamil and diltiazem; instability requires synchronized cardioversion. A similar baseline QRS does not alone prove supraventricular origin.

Inferior STEMI (ST elevation II, III, aVF, reciprocal aVL) with Mobitz type I…

Inferior MI can cause transient AV nodal block. Treat bradycardia when it causes hemodynamic compromise; atropine may help nodal block, with pacing if needed. Anterior-MI conduction block is more concerning for infranodal disease.

12-lead ECG with peaked narrow-based T waves in V2–V4, flattened P waves, and QRS…

New hyperkalemia on stable ACE inhibitor or MRA → look for trimethoprim, NSAIDs, or heparin; give calcium first if ECG changes. Exception: recent MRA dose increase → MRA is the precipitant.

Regular wide-complex tachycardia at about 168/min, QRS about 180 ms, LBBB-like…

Wide-complex tachycardia + prior MI or low EF → ventricular tachycardia regardless of stability; verapamil → collapse. Exception: proven SVT with QRS identical to baseline bundle branch block.

Convex ST-segment elevation in V1–V5, maximal (5 mm) in V2, with reciprocal ST…

After fibrinolysis → check the lead of maximal ST elevation at 60–90 minutes; <50% resolution → rescue PCI now. Exception: ≥50% resolution → angiography within 2–24 hours.

Atrial fibrillation with rapid ventricular response: irregularly irregular narrow QRS…

Sudden cortical deficits + infarcts in more than one arterial territory + atrial fibrillation → cardioembolism → DOAC, not antiplatelet. Exception: mechanical valve or moderate-severe mitral stenosis → warfarin.

Deep, symmetric T-wave inversions in V2–V4 without ST elevation or Q waves (Wellens…

NSTEMI with rising troponin or new ischemic T-wave changes (including Wellens) → angiography within 24 hours; never stress test or lyse. Exception: refractory pain, instability, or VT → within 2 hours.

Chaotic, disorganized baseline with variable-amplitude undulations and no identifiable…

Pulseless VF or VT → immediate unsynchronized shock, then 2 minutes of CPR. Exception: asystole or PEA → CPR plus early epinephrine, no shock.

12-lead ECG with horizontal ST depression in V1–V3, tall broad R waves with R/S ratio…

Ischemic chest pain with ST depression maximal in V1–V3 and tall R waves warrants posterior leads and urgent assessment for posterior coronary occlusion. A normal initial troponin does not exclude infarction.

ST-segment elevation in leads II, III, and aVF with reciprocal ST depression in leads…

Resuscitated from ventricular fibrillation + territorial ST elevation with reciprocal depression → acute coronary occlusion → emergency angiography, even if comatose. Exception: diffuse elevation with PR depression → pericarditis.

Rhythm strip of torsades de pointes: polymorphic QRS complexes twisting in amplitude…

Long-QT polymorphic VT suggests torsades de pointes. Sustained polymorphic VT requires immediate unsynchronized shock; magnesium, correction of potassium, and withdrawal of QT-prolonging drugs help prevent recurrence.

Flattened or inverted T waves in multiple leads with prominent U waves immediately…

Loop diuretic with hypokalemia and U waves → check and replace magnesium, or potassium repletion fails. Exception: normal magnesium → potassium replacement alone suffices.

Polymorphic VT with twisting QRS axis around the isoelectric baseline (torsades de…

Torsades with QTc >500 ms on QT-prolonging drugs plus low potassium and magnesium → acquired long QT; give IV magnesium, stop drugs. Exception: prolonged baseline QT or family sudden death → congenital.

Hyperkalemia ECG

Hyperkalemia: peaked T waves progressing to a widened QRS and sine wave — calcium gluconate first.

Anterior STEMI

Anterior STEMI: ST elevation V1–V4 with reciprocal inferior depression — LAD occlusion; cath lab, not serial troponins.

Inferior STEMI

Inferior STEMI with RV involvement: ST elevation III > II and in V4R — preload-dependent; fluids, no nitrates.

AVNRT

AVNRT: regular narrow-complex tachycardia with buried P waves — vagal maneuvers, then adenosine.

Torsades de pointes

Torsades is polymorphic VT associated with prolonged QT. Sustained episodes require immediate unsynchronized shock; give magnesium, correct electrolytes, and stop QT-prolonging drugs to prevent recurrence.

Ventricular fibrillation

Ventricular fibrillation: chaotic, disorganized electrical activity — immediate defibrillation.

Ventricular tachycardia

Monomorphic VT: regular wide-complex tachycardia — unstable → synchronized cardioversion; stable → amiodarone/procainamide.

Wolff Parkinson White

WPW: short PR interval with a slurred delta wave — avoid AV-nodal blockers if AF develops; procainamide or cardioversion.

Echo1 file

Large circumferential pericardial effusion with early diastolic right ventricular…

Pericardial effusion with chamber collapse supports tamponade physiology; assess perfusion and clinical findings. Hemodynamic instability requires urgent drainage. Avoid diuretics and vasodilators in tamponade; absent collapse alone does not establish safety.

Fundus / OCT1 file

EYE · Step 2 CK

Branch retinal vein occlusion

Branch retinal vein occlusion produces hemorrhage within a retinal vascular sector, unlike the diffuse hemorrhagic pattern of central retinal vein occlusion.

Fundus3 files

Central retinal artery occlusion

Central retinal artery occlusion causes sudden painless monocular vision loss with retinal pallor and a cherry-red spot. Arrange immediate stroke-center assessment and evaluate for giant cell arteritis when clinically indicated.

Fundus2 files

Central retinal vein occlusion

Central retinal vein occlusion: diffuse retinal hemorrhages in all quadrants ('blood and thunder') — hypertension, glaucoma, hyperviscosity; anti-VEGF for macular edema.

Bilateral optic disc edema with blurred disc margins, elevation of the disc surface…

Bilateral papilledema + normal MRI/MRV in obese young woman → lumbar puncture opening pressure, then acetazolamide and weight loss. Exception: progressive vision loss needs urgent surgical decompression.

Early fetal heart-rate decelerations

Early decelerations mirror the contraction (nadir at the peak) — fetal head compression; benign, no intervention.

Tracing1 file

Late decelerations

Late decelerations suggest uteroplacental insufficiency. Reposition, stop oxytocin, correct hypotension or tachysystole, and give oxygen only for maternal hypoxemia. Persistent category III tracing despite resuscitation requires expedited delivery.

Prolonged fetal heart-rate deceleration

A prolonged fetal deceleration lasts 2 to less than 10 minutes; 10 minutes defines a baseline change. Begin immediate corrective measures and evaluate reversible causes; persistent bradycardia may require expedited delivery before that threshold.

Variable decelerations

Variable decelerations: abrupt V-shaped drops of variable timing — cord compression; amnioinfusion for recurrent variables.

Endoscopy3 files

Bleeding peptic ulcers on endoscopy

Peptic ulcer bleeding: active bleeding or a visible vessel needs endoscopic therapy plus IV PPI; a clean ulcer base can be discharged early.

MRI1 file

Sagittal MRI lumbar spine showing an epidural mass compressing the cauda equina at the…

Saddle numbness + urinary retention + reduced anal tone → emergent MRI without and with contrast. Exception: MRI contraindicated → CT myelography.

MRI3 files

Cauda equina MRI

Cauda equina compression with bladder dysfunction, saddle sensory loss, or progressive deficits requires emergency MRI and urgent decompression as soon as feasible.

Lateral neck radiograph thumb sign: enlarged rounded epiglottis with thickened…

Drooling + tripod + stridor without cough + thumb sign → keep upright, no IV or tongue depressor, secure airway in OR. Exception: croup with steeple sign → examination safe.

Synovial fluid comparison showing turbid, purulent fluid characteristic of septic…

Suspected septic arthritis requires prompt arthrocentesis with cell count, Gram stain, culture, and crystal analysis. Obtain samples before antibiotics when feasible, but never delay antibiotics in sepsis; a low cell count or crystals do not exclude infection.

Jaundiced term newborn with cephalocaudal yellow discoloration extending to the chest;…

Use age-, gestation-, and neurotoxicity-risk-adjusted bilirubin thresholds. At escalation thresholds, provide intensive phototherapy and hydration; consider IVIG selectively for isoimmune hemolysis with bilirubin rising despite intensive phototherapy.

Bilateral non-purulent bulbar conjunctival injection with limbic sparing and diffuse…

Infants with persistent fever may have incomplete Kawasaki disease. Evaluate inflammatory markers and coronary findings, and treat when the incomplete-disease algorithm supports the diagnosis; a normal early echocardiogram or concurrent infection does not alone exclude it.

Hand foot mouth disease

Hand-foot-and-mouth disease (coxsackie A16): grey-oval vesicles on palms, soles and mouth — supportive care.

Measles rash

Measles: cough, coryza, conjunctivitis, Koplik spots, then a cephalocaudal morbilliform rash — vitamin A; airborne isolation; notify public health.

Necrotizing fasciitis

Necrotizing fasciitis: pain out of proportion, then dusky skin, bullae and crepitus — surgical exploration is the diagnosis; imaging must never delay the OR.

Stevens Johnson syndrome

SJS/TEN: dusky macules coalescing into sheets of epidermal detachment with mucosal erosions — stop the drug, burn-unit care; <10% BSA is SJS, >30% is TEN.

Herpes zoster

Herpes zoster: grouped vesicles confined to one dermatome that does not cross midline — valacyclovir within 72 h; vaccinate adults ≥50 with recombinant zoster vaccine.

Blood smear1 file

Numerous schistocytes (helmet cells, triangular fragmented red cells) with markedly…

Fragmented red cells + platelets <30,000/mm³ + normal PT/PTT/fibrinogen + minimal renal injury → suspect TTP (ADAMTS13); start plasma exchange. Exception: dominant AKI → consider HUS.

Heart sounds and murmurs

Midsystolic click then late systolic murmur: mitral valve prolapse. Crescendo–decrescendo murmur radiating to the carotids: aortic stenosis.

Respiratory sounds

Inspiratory stridor = upper-airway obstruction (secure the airway); expiratory wheeze = lower-airway narrowing; focal crackles = consolidation.

Absent or markedly decreased color Doppler flow to the affected testis with an…

Abrupt scrotal pain + absent cremasteric reflex + high transverse testis → torsion → immediate exploration. Exception: blue-dot upper-pole nodule with normal flow → appendix testis torsion.

Ectopic pregnancy ultrasound

An empty uterus with elevated hCG raises concern for ectopic pregnancy but is not diagnostic alone. Combine symptoms, serial hCG, and transvaginal ultrasound; use methotrexate only when appropriate criteria are met, and urgent surgery for suspected rupture or instability.

Acute cholecystitis ultrasound

Acute cholecystitis on ultrasound: stones with acoustic shadowing, wall >3 mm, pericholecystic fluid, sonographic Murphy sign.

Hydronephrosis ultrasound

Hydronephrosis indicates collecting-system dilation but does not alone establish obstructive AKI. Assess the obstruction level: catheterize for retention, and use ureteral stenting or nephrostomy when upper-tract drainage is required; infected obstruction is an emergency.

Hydatidiform mole ultrasound

Complete mole: 'snowstorm' uterus with no fetal parts, β-hCG far above dates, theca-lutein cysts — suction curettage, then weekly β-hCG and contraception.

OBG · Step 2 CK

Ovarian torsion on ultrasound

Suspected ovarian torsion is an urgent surgical diagnosis. Ultrasound can support it with an enlarged ovary and abnormal or absent flow, but preserved Doppler flow does not exclude torsion.

Frog-leg lateral radiograph showing posterior-inferior displacement of the femoral…

Obese adolescent plus hip/knee pain plus obligatory external rotation with flexion -> slipped capital femoral epiphysis; treat with in-situ pinning; avoid forceful reduction.

Intussusception target sign

Intussusception: target sign on ultrasound — air or hydrostatic enema is both diagnostic and therapeutic; surgery if peritonitis or failed reduction.

Pyloric stenosis ultrasound

Pyloric stenosis: muscle >3–4 mm thick and channel >15–17 mm — correct hypochloremic hypokalemic alkalosis before pyloromyotomy.

A soft left carotid bruit

Retinal artery occlusion after age 50 + jaw claudication, polymyalgia, or pale disc edema → ESR/CRP and glucocorticoids now, biopsy later. Exception: no arteritic features → stroke-equivalent workup.

Duodenal atresia

Double-bubble with no distal gas: duodenal atresia — bilious vomiting on day 1, Down syndrome association.

Abdominal aortic aneurysm

AAA repair is recommended at ≥5.5 cm in men, ≥5.0 cm in women, or for attributable symptoms; rapid growth also prompts repair assessment.

CT chest with oral contrast showing extraluminal contrast extravasation from the left…

Esophageal perforation with an uncontained leak or sepsis → antibiotics and emergency surgical repair, ideally within 24 hours. Exception: small contained leak, stable, no sepsis → nonoperative care or endoscopic stent.

6-cm hepatic mass with arterial hyperenhancement and portal venous washout (LI-RADS…

Advanced HCC with preserved liver function may receive atezolizumab–bevacizumab or another appropriate immunotherapy combination. Evaluate and treat varices before bevacizumab; a non-bevacizumab regimen may suit bleeding risk. Transplant or significant autoimmune disease requires a different individualized approach.

Noncontrast head CT of a neonate showing bilateral periventricular hyperdense…

Periventricular calcifications + microcephaly + hearing loss → congenital CMV → urine or saliva PCR before 21 days. Exception: scattered cortical calcifications + hydrocephalus → toxoplasmosis.

Contrast-enhanced abdominal CT with coarse pancreatic parenchymal calcifications,…

Chronic pancreatitis + isolated gastric varices + splenomegaly with normal liver → splenic vein thrombosis; bleeding → splenectomy. Exception: esophageal varices or cirrhotic liver → generalized portal hypertension.

Segmental colonic wall thickening with adjacent mesenteric fat stranding involving the…

Sudden crampy pain + modest bloody stool + recent low-flow state → ischemic colitis at a watershed (splenic flexure); supportive care. Exception: peritoneal signs or pneumatosis → transmural infarction, surgery.

Hydrocephalus CT

Hydrocephalus: ventriculomegaly out of proportion to sulcal atrophy — communicating vs obstructive decides shunt vs ETV.

Aortic dissection

Widened mediastinum with tearing chest pain: dissection until proven otherwise — CT angiography, and control heart rate before pressure.

Acute respiratory distress syndrome

ARDS involves acute hypoxemia with bilateral opacities not fully explained by cardiac failure or fluid overload. Use lung-protective ventilation with tidal volume around 6 mL/kg predicted body weight and plateau pressure at or below 30 cm H₂O.

CXR1 file

Neonatal chest radiograph with an orogastric tube coiled in a blind upper esophageal…

A coiled tube in the upper pouch with abdominal gas suggests esophageal atresia with distal fistula. Stabilize and obtain pediatric surgical assessment; associated anomalies and family goals guide individualized care.

Cardiogenic pulmonary edema

Cardiogenic pulmonary edema: cardiomegaly, vascular cephalization, Kerley B lines and perihilar 'bat-wing' opacities.

Pleural effusion

Pleural effusion: blunted costophrenic angle with a meniscus — decubitus film or ultrasound before thoracentesis; Light's criteria classify it.

Epiglottitis and croup

Thumbprint sign on lateral neck film = epiglottitis (secure airway in the OR); steeple sign on AP = croup (dexamethasone ± racemic epinephrine).

Cavitary tuberculosis

Reactivation tuberculosis: apical/upper-lobe cavitation — airborne isolation, three sputum AFB smears and NAAT.

Sinus rhythm, QRS 162 ms, LBBB morphology with broad notched R waves in I/aVL/V5-V6,…

CRT is strongly indicated in appropriate patients with LVEF ≤35%, sinus rhythm, LBBB, QRS ≥150 ms, and persistent NYHA II–ambulatory IV symptoms despite guideline-directed therapy. Selected patients with LBBB and QRS 120–149 ms may also benefit.

Infant ECG at 118/min with QT 380 ms (QTc about 530 ms) and notched low-amplitude T…

An infant event triggered by startle plus family syncope or young sudden death warrants QTc assessment and cardiology evaluation. BRUE applies only when history and examination reveal no explanation.

Brugada pattern

Type 1: coved ST elevation ≥2 mm in V1 or V2 with T-wave inversion. ICD is indicated after survived cardiac arrest or documented spontaneous sustained VT; consider it for arrhythmic syncope.

Rapid irregularly irregular rhythm (atrial fibrillation) abruptly terminating into a…

Tachycardia-bradycardia syndrome with symptomatic pauses → pacemaker before rate-control drugs, which otherwise prolong pauses. Exception: already paced → rate control is safe.

Regular narrow-complex tachycardia at ~180/min with no discernible P waves and a…

Regular narrow-complex tachycardia with terminal pseudo-R' in V1 that vanishes in sinus rhythm → AVNRT. Exception: delta wave or short PR in sinus rhythm → accessory-pathway AVRT.

Sinus tachycardia with an S1Q3T3 pattern (S wave in lead I, Q wave and T-wave…

Suspected PE with shock requires urgent assessment and reperfusion planning. Bedside echocardiography can guide emergency treatment if CT is unsafe; select thrombolysis, catheter therapy, or surgery according to severity and bleeding risk.

Sinus tachycardia with low-voltage QRS complexes in limb and precordial leads and…

Low voltage + alternans + JVD + hypotension → tamponade: small fluid bolus while pericardiocentesis is prepared; avoid diuretics, nitrates, positive pressure. Exception: arrest → drain immediately.

Diffuse concave-upward (saddle-shaped) ST-segment elevation in multiple non-contiguous…

Pericarditis and arthralgias during exposure to hydralazine, procainamide, or isoniazid suggest drug-induced lupus; stop the implicated drug. Antihistone antibodies are supportive, not specific. Nephritis, anti-dsDNA antibodies, or low complement warrant broader evaluation and do not exclude drug-induced disease.

Diffuse concave (saddle-shaped) ST elevation in I, II, aVF, V2–V6 with PR depression…

Pericarditis weeks after MI → high-dose aspirin plus colchicine. Exception: no recent MI → any NSAID plus colchicine; tamponade → pericardiocentesis.

Diffuse concave ST elevation across multiple territories with PR depression in the…

Diffuse ST elevation with PR depression supports acute pericarditis; uncomplicated cases are usually treated with an NSAID and colchicine. Troponin elevation may reflect myopericarditis; territorial changes or ischemic symptoms require evaluation for acute coronary syndrome.

Left bundle branch block

LBBB shows QRS ≥120 ms with broad lateral R waves. New LBBB alone is not a STEMI equivalent; assess ischemic symptoms and Sgarbossa or modified Sgarbossa findings.

Long QT syndrome

Prolonged QT predisposes to torsades; QTc above 500 ms is a high-risk marker, not a required diagnostic threshold for long-QT syndrome. Review drugs, electrolytes, symptoms, and family history.

Acute pericarditis

Acute pericarditis: diffuse concave ST elevation with PR depression, and PR elevation in aVR — not a territorial STEMI.

EEG2 files

Hypsarrhythmia: chaotic, high-amplitude (>200 µV) multifocal spikes and slow waves…

Infant spasm clusters + regression + hypsarrhythmia → start hormonal therapy promptly, with workup in parallel. Exception: features of tuberous sclerosis → vigabatrin.

Endoscopy1 file

Esophagus with concentric rings (trachealization), longitudinal furrows, and white…

Atopic young adult + food impaction + rings and furrows + ≥15 eos/HPF → PPI, swallowed topical steroid, or elimination diet. Exception: systemic steroids, montelukast, cromolyn, and omalizumab are not recommended.

Hearing tests and audiograms

Weber lateralizes to the conductive-loss ear or away from the sensorineural-loss ear; Rinne BC > AC means conductive loss.

Mild NPDR: scattered microaneurysms and dot-blot hemorrhages in the posterior pole…

Preexisting diabetes + pregnancy → dilated eye exam in first trimester, then every trimester and for 1 year postpartum. Exception: rapid A1c drop → expect transient worsening; keep control tight.

Advanced glaucomatous cupping bilaterally, cup-to-disc ratio approximately 0.8 with…

Open-angle glaucoma → prostaglandin analog first. Exception: asthma or COPD → avoid timolol; add an alpha-2 agonist or carbonic anhydrase inhibitor if more lowering is needed.

CRAO: diffuse retinal whitening with a cherry-red spot at the fovea; arteritic variant…

Fundus2 files

Diabetic retinopathy

Diabetic retinopathy: microaneurysms, dot-blot hemorrhages and hard exudates; neovascularization marks proliferative disease — anti-VEGF or laser.

Hypertensive retinopathy

Hypertensive retinopathy with papilledema defines malignant hypertension — end-organ damage; IV therapy, lower MAP ≤25% in the first hour.

Fundus3 files

Papilledema fundus

Papilledema: elevated, blurred disc margins with obscured vessels — imaging before lumbar puncture; idiopathic intracranial hypertension in obese young women.

Histology1 file

Columnar epithelium with interspersed goblet cells (intestinal metaplasia) replacing…

Nondysplastic Barrett esophagus 3 cm or longer → endoscopy every 3 years with acid suppression. Exception: dysplasia → endoscopic eradication; short segment and lower risk → 5 years.

Micro3 files

Acid fast bacilli

Acid-fast bacilli on Ziehl-Neelsen stain: mycobacteria — NAAT confirms M. tuberculosis; culture for susceptibilities.

Micro1 file

Needle-shaped monosodium urate crystals appearing yellow when parallel to the slow…

Starting urate-lowering therapy → add colchicine, NSAID, or low-dose prednisone prophylaxis for 3–6 months, or expect mobilization flares. Exception: HLA-B58:01 positive → avoid allopurinol.

MRI3 files

Multiple sclerosis MRI

Multiple sclerosis: periventricular ovoid T2/FLAIR lesions ('Dawson fingers') — dissemination in space and time by McDonald criteria.

Head impulse test

Acute vestibular syndrome: an abnormal head impulse (catch-up saccade) points to vestibular neuritis; a normal one with nystagmus or skew suggests stroke (HINTS).

Positional vertigo testing

BPPV: Dix–Hallpike reproduces brief vertigo with torsional upbeating nystagmus after a latency — treat with the Epley maneuver, not imaging or drugs.

Erythema infectiosum

Erythema infectiosum (parvovirus B19): slapped cheeks then lacy limb rash — no longer contagious once the rash appears; risk of aplastic crisis in sickle cell and hydrops in pregnancy.

Roseola infantum

Roseola (HHV-6): 3–5 days of high fever, then a rash as the fever breaks — febrile seizures are the key complication; supportive care.

Rubella exanthem

Rubella: mild face-to-trunk pink rash with posterior auricular/occipital nodes — main risk is congenital rubella; check immunity before pregnancy (MMR is live, avoid in pregnancy).

Scarlet fever rash

Scarlet fever: sandpaper rash with Pastia lines and strawberry tongue after strep pharyngitis — penicillin or amoxicillin to prevent rheumatic fever.

Absent thymic shadow

Absent thymic shadow with hypocalcemia and a conotruncal heart defect: DiGeorge (22q11.2 deletion) — check T cells and give irradiated blood products.

Varicella rash

Varicella: crops of lesions in different stages (papule, vesicle, crust) — contagious until all crusted; acyclovir for adolescents, adults and the immunocompromised.

Acanthosis nigricans

Acanthosis nigricans: velvety hyperpigmented neck and axillae — insulin resistance; abrupt onset in an older adult prompts a search for gastric adenocarcinoma.

Bilateral periorbital edema in a young child with nephrotic syndrome, most prominent…

Child on high-dose prednisone for nephrotic syndrome → give inactivated vaccines now (PCV20 after completed PCV13 series). Exception: MMR, varicella, and intranasal influenza wait ≥1 month after high-dose steroids.

Normal otoscopy: intact translucent tympanic membrane with normal landmarks and no…

Oscillopsia + bilateral abnormal head impulse test + high-frequency hearing loss during aminoglycoside therapy → gentamicin toxicity; stop it. Exception: loop diuretic → cochlear only, usually reversible.

White pupillary reflex (leukocoria) in the right eye on flash photograph with absent…

Leukocoria or absent red reflex in an infant → urgent ophthalmology and dilated examination under anesthesia. Exception: staging imaging needed → MRI, never CT.

GAS pharyngitis: erythematous enlarged tonsils with white exudates and palatal petechiae

Pharyngitis 2 to 4 weeks earlier + migratory polyarthritis + new mitral regurgitation → rheumatic fever by molecular mimicry. Exception: hematuria + low C3 → post-streptococcal glomerulonephritis, immune complexes.

AP neck radiograph steeple sign: symmetric subglottic tracheal narrowing; lateral view…

Croup with stridor at rest → dexamethasone + racemic epinephrine, observe 2 to 4 hours. Rebound → repeat epinephrine and admit. Exception: toxic child unresponsive to epinephrine → bacterial tracheitis.

Central corneal white-yellow stromal infiltrate with overlying epithelial defect and…

Contact lens wearer + stromal infiltrate ± hypopyon → bacterial keratitis; culture and intensive topical antibiotics, no patch. Exception: branching dendrite → herpes simplex, treat with antivirals.

Bulging, erythematous, opaque right tympanic membrane with obscured landmarks and…

Acute otitis media + purulent conjunctivitis or amoxicillin in past 30 days → amoxicillin-clavulanate. Exception: severe penicillin allergy → non-beta-lactam alternative.

Fluorescein staining under cobalt blue light showing a well-demarcated, bright green…

Corneal abrasion without contact lens use → topical antibiotic, no patch; always evert the lid. Exception: contact lens wearer → antipseudomonal fluoroquinolone.

Right Horner syndrome: mild right upper lid ptosis and right miosis with anisocoria…

New Horner syndrome + ipsilateral neck or face pain → urgent CTA or MRA for carotid dissection. Exception: subacute arm pain in a smoker → chest imaging for apical tumor.

Nodular melanoma: uniformly dark, dome-shaped nodule lacking asymmetry or border…

Rapidly growing, symmetric, uniformly dark nodule that lacks ABCDE features -> nodular melanoma from early vertical growth phase; biopsy any rapidly changing lesion.

Phalen test: right wrist flexion at 90 degrees held for 60 seconds reproducing…

Night-predominant thumb/index/middle numbness plus positive Phalen/Tinel signs point to carpal tunnel syndrome; splint empirically. Before surgery or if the diagnosis is uncertain, confirm and grade severity with NCS/EMG; ultrasound is a secondary alternative.

Thin linear gray-white burrows 3 to 8 mm long in the finger web spaces and wrist, with…

Nocturnal itch + web-space burrows + itchy household contacts → scabies; treat patient and all contacts at once with permethrin. Exception: crusted scabies → add oral ivermectin.

Monomorphic punched-out erosions and hemorrhagic crusted vesicles superimposed on…

Fever and monomorphic punched-out vesicles or erosions on eczema suggest eczema herpeticum: begin systemic acyclovir promptly. Bacterial superinfection may coexist; honey-colored crusting does not exclude HSV.

Palpable, non-blanching purpuric papules and plaques concentrated on the buttocks and…

IgA vasculitis with severe abdominal pain (intussusception excluded) → oral corticosteroids. Exception: mild disease with normal urinalysis → NSAID for arthralgia.

Deep vein thrombosis

Unilateral calf swelling >3 cm: DVT — Wells score, D-dimer if low probability, compression ultrasound; anticoagulate for ≥3 months.

Sclerodactyly with taut, shiny, bound-down skin over the fingers and limited flexion…

Raynaud phenomenon with sclerodactyly or pitting scars → nailfold capillaroscopy to show scleroderma-pattern microangiopathy. Exception: absent pulses or single-digit ischemia → evaluate large vessels with arteriography.

Bilateral diffuse, tender parotid swelling extending anterior to and below the ear

Bilateral parotitis + orchitis in an unvaccinated adolescent → mumps; buccal swab RT-PCR, supportive care, isolate 5 days. Exception: unilateral parotitis with ductal pus → bacterial parotitis.

Graves orbitopathy

Graves orbitopathy: proptosis and lid retraction, unique to Graves — TSI/TRAb; radioiodine can worsen eye disease, so steroids cover it or methimazole/surgery is chosen.

HSV dendritic keratitis

An HSV dendritic epithelial ulcer requires antiviral therapy; topical steroids are contraindicated during active epithelial ulceration. Stromal HSV disease may require specialist-directed steroids with antiviral coverage.

IgA vasculitis purpura

Palpable purpura on the legs and buttocks in a child: IgA vasculitis (HSP) — check urinalysis for nephritis; supportive care, steroids for severe abdominal or renal disease.

Kawasaki disease

Kawasaki disease: ≥5 days of fever with conjunctivitis, oral changes, rash, extremity changes, cervical node — IVIG plus aspirin within 10 days; echo for coronary aneurysms.

Malar rash lupus

Malar rash that spares the nasolabial folds: SLE — ANA screen, then anti-dsDNA/anti-Smith; hydroxychloroquine for everyone.

Atopic dermatitis

Atopic dermatitis: pruritic, lichenified flexural plaques in a child with asthma or allergic rhinitis — emollients and topical steroids; watch for eczema herpeticum.

Basal cell carcinoma

Basal cell carcinoma: pearly, telangiectatic papule with a rolled edge on sun-exposed skin — locally destructive, rarely metastasizes; Mohs on the face.

Erysipelas

Erysipelas: raised, sharply demarcated fiery erythema (group A strep) versus cellulitis's indistinct border — beta-lactam; add MRSA cover only for purulence or MRSA risk factors.

Erythema migrans

Erythema migrans: expanding target lesion ≥5 cm days after a tick bite — clinical diagnosis; doxycycline, no serology needed at this stage.

Erythema nodosum

Erythema nodosum: tender shin nodules — look for sarcoidosis, streptococcal infection, IBD, TB, OCPs; treat the cause plus NSAIDs.

Bullous pemphigoid and pemphigus

Tense bullae in the elderly = bullous pemphigoid (subepidermal, Nikolsky negative); flaccid blisters and oral erosions = pemphigus vulgaris (Nikolsky positive).

Pressure ulcer

Full-thickness pressure injury: stage 3 exposes subcutaneous fat, stage 4 exposes bone/tendon/muscle — offloading, moisture control, debridement of necrosis.

Plaque psoriasis

Plaque psoriasis: sharply demarcated salmon plaques with silvery scale on extensor surfaces; pitting nails — topical steroids/vitamin D analogues, biologics for extensive disease.

Scabies burrows

Scabies: intensely pruritic burrows in finger webs and wrists, worse at night — permethrin 5% for the patient and all contacts; wash bedding.

Squamous cell carcinoma

Squamous cell carcinoma: scaly, crusted, indurated nodule — arises from actinic keratosis, chronic wounds and scars; can metastasize.

Tinea corporis

Tinea corporis: annular plaque with an advancing scaly edge and central clearing — KOH shows hyphae; topical azole, oral terbinafine for scalp or nails.

Blood smear1 file

Numerous lymphoblasts: large cells with scant cytoplasm, fine immature chromatin,…

ALL with WBC ≥100,000/mm³ or hyperuricemia before chemotherapy → hydration + rasburicase. Exception: G6PD deficiency → allopurinol, because rasburicase causes hemolysis and methemoglobinemia.

Blood smear1 file

Iron deficiency smear

Iron deficiency: microcytic, hypochromic cells with marked anisocytosis (high RDW) and pencil cells — low ferritin confirms; find the bleeding source.

Malaria blood smear

Intraerythrocytic ring forms: malaria (thick and thin smears; falciparum gets IV artesunate if severe) — Babesia's Maltese cross is the tick-borne mimic.

Megaloblastic anemia smear

Megaloblastic anemia: macro-ovalocytes with hypersegmented neutrophils — B12 vs folate decided by methylmalonic acid; replace B12 before folate.

Schistocytes blood smear

Schistocytes: fragmented helmet cells of microangiopathic hemolysis — TTP (plasma exchange), HUS, DIC (treat the cause).

Sickle cell smear

Sickle cell disease smear: sickled erythrocytes, target cells and Howell-Jolly bodies (functional asplenia) — hydroxyurea; vaccinate and penicillin prophylaxis.

Spherocytes blood smear

Spherocytes: small dense cells without central pallor — hereditary spherocytosis (osmotic fragility/EMA binding, Coombs negative) versus warm AIHA (Coombs positive).

Oculovestibular reflex

Brain death: cold water in the ear produces no eye movement at all — an absent oculovestibular reflex is one required finding before the apnea test.

Transvaginal ultrasonography, sagittal uterus, thin homogeneous endometrial stripe…

Postmenopausal bleeding needs prompt evaluation. Current ACOG guidance recommends transvaginal ultrasound plus endometrial sampling for most patients; a thin stripe does not exclude malignancy, especially with persistent or recurrent bleeding.

Polycystic ovarian morphology with more than 20 small peripheral follicles per ovary…

Oligomenorrhea + hyperandrogenism → 2-hour 75-g oral glucose tolerance test, not fasting glucose alone. Exception: first exclude pregnancy, hyperprolactinemia, and thyroid disease.

Enlarged ovary with 20 or more small peripheral follicles (string-of-pearls pattern)

PCOS without pregnancy desire → combined oral contraceptive first; screen glucose and lipids. Exception: wants pregnancy now → letrozole; estrogen contraindicated → progestin-based therapy.

Ovary with 20 or more peripheral antral follicles in polycystic ovarian morphology

Anovulatory PCOS, patent tubes, normal semen analysis → letrozole first. Exception: letrozole failure → gonadotropins or ovarian drilling; tubal or severe male factor → IVF.

Transvaginal sagittal uterus with thin homogeneous endometrial stripe measuring 3 mm…

Systemic estrogen with an intact uterus generally requires endometrial protection with a progestogen. Most patients with postmenopausal bleeding now warrant both transvaginal ultrasound and endometrial sampling; a stripe ≤4 mm is not an automatic biopsy exemption.

Transvaginal ultrasound of a well-circumscribed heterogeneous hypoechoic intramural…

Initial bleeding flare, then amenorrhea, hot flashes, low estradiol, low FSH/LH, and fibroid shrinkage → GnRH agonist. Exception: immediate suppression with mild symptoms → antagonist with add-back.

Hyperreflexia and sustained rhythmic clonus at both ankles

Serotonergic drug combination + onset within hours + clonus, hyperreflexia, diaphoresis, diarrhea → serotonin syndrome → stop drugs, benzodiazepines, cooling. Exception: rigidity over days after antipsychotic → neuroleptic malignant syndrome.

Jaundiced and has asterixis

Acute liver failure after a possible ingestion warrants immediate acetaminophen assessment and empiric acetylcysteine when toxicity is plausible. A low late level does not exclude toxicity; investigate other causes concurrently.

Distal femoral metaphyseal mixed lytic-sclerotic lesion with sunburst periosteal…

Adolescent + localized metaphyseal osteoid-producing sarcoma → neoadjuvant chemotherapy, then wide limb-sparing resection, then adjuvant chemotherapy. Exception: Ewing sarcoma → radiation acceptable for local control.

AP lumbar spine radiograph showing bamboo spine: thin, vertical marginal…

Young adult + inflammatory back pain + uveitis + syndesmophytes → enthesitis with reactive new bone formation. Exception: reactive arthritis shares this mechanism but follows enteric or genitourinary infection.

AP shoulder radiograph of posterior dislocation showing lightbulb sign of internally…

Seizure or electrocution + arm locked in internal rotation → posterior dislocation; get axillary view or CT for anteromedial (reverse Hill-Sachs) defect. Exception: fall on abducted arm → anterior, posterolateral defect.

AP knee radiograph showing asymmetric medial compartment joint space narrowing,…

Joint pain that worsens with activity and improves with rest, with brief morning stiffness, normal inflammatory markers, and osteophytes with joint space narrowing on X-ray, points to osteoarthritis, mechanical cartilage degeneration, not autoimmune or crystal disease.

Voiding cystourethrogram showing grade III vesicoureteral reflux with bilateral…

Febrile UTI + moderate or higher vesicoureteral reflux in a young child → recurrent pyelonephritis → renal cortical scarring. Exception: persistent fever despite therapy → look for abscess.

Metaphyseal cupping, fraying, and widening of the distal radius and ulna with a…

Exclusively breastfed infant + bowing, rosary, low 25-hydroxyvitamin D, high PTH and alkaline phosphatase → oral vitamin D3 plus calcium. Exception: normal vitamin D and PTH with low phosphate → phosphate-wasting rickets.

Colles fracture

Colles fracture: dorsally angulated distal radius after a fall on the outstretched hand — closed reduction and cast; check the median nerve.

Femoral neck fracture

Displaced femoral neck fracture: shortened, externally rotated leg — hemiarthroplasty/THA in the elderly because the femoral head's blood supply is lost.

Rheumatoid arthritis hand

Rheumatoid hand: MCP/PIP erosions, periarticular osteopenia, ulnar deviation — contrast with osteoarthritis (DIP, osteophytes).

Salter Harris fracture

Salter-Harris II: fracture through the physis exiting the metaphysis — the commonest type; closed reduction and cast.

Scaphoid fracture

Scaphoid fracture: snuffbox tenderness with a normal initial film still gets a thumb spica and repeat imaging — proximal-pole nonunion and avascular necrosis.

Anterior shoulder dislocation

Anterior shoulder dislocation: humeral head sits below and medial to the glenoid — check axillary nerve sensation before and after reduction.

Symmetric hypodensity within the bilateral parieto-occipital white matter without…

Severe hypertension + headache, confusion, visual loss + symmetric posterior white matter edema → PRES → controlled BP lowering. Exception: subarachnoid hyperdensity → aneurysmal hemorrhage workup.

Contrast-enhanced axial CT of the abdomen showing a large heterogeneous right renal…

Child with intrarenal flank mass and claw sign → chest CT staging, then nephrectomy; no percutaneous biopsy. Exception: suprarenal mass encasing vessels → urine HVA/VMA for neuroblastoma.

Wall thickening/mass at the gastroesophageal junction on contrast-enhanced CT…

Biopsy-proven esophageal or junctional cancer with negative CT and PET-CT → endoscopic ultrasound for T and N stage. Exception: tumor at or above the carina → add bronchoscopy.

CXR1 file

Emphysema

Emphysema: hyperinflation with flattened hemidiaphragms and a narrow vertical heart — diagnosis rests on spirometry (FEV1/FVC <0.7), not the film.

Miliary tuberculosis

Miliary tuberculosis: diffuse millet-seed nodules — disseminated disease; start four-drug therapy without waiting for cultures.

Neonatal respiratory distress

Neonatal respiratory distress syndrome: ground-glass lungs with air bronchograms in a preterm infant — surfactant and CPAP.

Sarcoidosis hilar adenopathy

Bilateral hilar lymphadenopathy in a young adult: sarcoidosis — biopsy shows noncaseating granulomas; exclude TB and lymphoma.

Sinus tachycardia at a rate of 110/min without ST-segment or T-wave abnormalities.

Hypotension after a nitrate in a PDE5-inhibitor user → supine position and IV fluids. Exception: tadalafil's nitrate-free window is 48 hours, not 24.

Digoxin effect

Digoxin effect: sagging 'reverse-tick' ST depression — effect, not toxicity; toxicity is arrhythmia plus GI/visual symptoms.

Sinus bradycardia with prolonged PR, QRS, and QT intervals, prominent Osborn (J) waves…

Bradycardia + prolonged PR, QRS, and QT + inferolateral J waves → hypothermia; measure core temperature with a low-reading probe. Exception: J waves with short QT → hypercalcemia.

Early beat with abnormal P-wave morphology (distinct from sinus P waves) preceding a…

Early beat with abnormal P wave, narrow QRS, and noncompensatory pause → premature atrial contraction; reassure, reduce caffeine. Exception: wide QRS, compensatory pause → premature ventricular contraction.

Coved-type (type 1) ST-segment elevation ≥2 mm in leads V1-V2 with a convex,…

Fever-provoked coved ST elevation in V1-V2 + syncope or family sudden death → Brugada syndrome: treat fever, avoid sodium channel blockers, evaluate for ICD. Exception: saddleback pattern alone is nondiagnostic.

Kayser Fleischer ring

Kayser-Fleischer ring: copper deposition in Descemet membrane — Wilson disease; low ceruloplasmin, high urinary copper; penicillamine or trientine, zinc.

Microscopy3 files

Giardia stool microscopy

Giardia: oval cysts in stool (pear-shaped trophozoites); foul, fatty diarrhea after camping or daycare exposure — stool antigen/PCR; metronidazole or tinidazole.

Micro2 files

Gram positive cocci

Gram-positive cocci in clusters suggest staphylococci. Confirm species and susceptibilities; suspected serious staphylococcal infection may require empiric MRSA coverage, then narrow confirmed MSSA to an appropriate beta-lactam.

Arterial-line pressure waveform

Arterial line: sharp upstroke and dicrotic notch; a damped trace (flattened, no notch) under-reads systolic pressure — flush and check the line before treating the number.

Central venous pressure waveform

CVP waveform: a, c, v waves with x and y descents; cannon a waves = AV dissociation, large v waves = tricuspid regurgitation; CVP alone poorly predicts fluid response.

Hysterosalpingography: tubal patency

Hysterosalpingography: free spill of contrast confirms tubal patency; a dilated, non-spilling tube is a hydrosalpinx — first-line tubal test in infertility.

Hysterosalpingography: uterine anomaly

HSG shows the cavity but cannot reliably distinguish septate from bicornuate uterus; assess the external contour with 3D transvaginal ultrasound or MRI. Hysteroscopic septum incision is considered for selected patients after counseling, especially with recurrent miscarriage.

Right external auditory canal fully occluded by cerumen obscuring the tympanic membrane

Weber toward the affected ear + negative Rinne + canal full of cerumen → remove the cerumen. Exception: perforation or prior ear surgery → avoid irrigation; remove manually.

Ishihara plate testing showing impaired red-green color discrimination; visual field…

Tuberculosis therapy + red-green color loss or central scotoma → stop ethambutol now and refer to ophthalmology. Risk rises with dose >15 mg/kg/day, therapy beyond 2 months, and renal impairment.

Heliotrope rash: violaceous edematous discoloration of the upper eyelids; Gottron…

Anti-Jo-1 + mechanic's hands + ILD -> antisynthetase syndrome; ILD, not CK, drives prognosis.

Pearly translucent papule with rolled telangiectatic border and central ulceration on…

BCC on the nose or another H-zone facial site -> Mohs micrographic surgery for the highest cure rate and tissue-sparing excision.

Gottron papules: flat-topped violaceous scaly papules over MCP and PIP joints of…

New dermatomyositis with anti-TIF1-γ, age over 40, or weight loss → CT chest, abdomen, and pelvis plus routine screening. Exception: low-risk profile → basic screening and surveillance.

Nodulocystic acne with deep inflammatory nodules and pseudocysts on jawline and cheeks…

Scarring nodular acne after failed oral antibiotic → isotretinoin; stop tetracyclines first. Exception: can become pregnant → risk program, two contraceptive methods, two negative pregnancy tests before starting.

Typical three-zone target lesions (dusky center, pale edematous ring, erythematous…

Recurrent acral target lesions 1–2 weeks after cold sores → continuous valacyclovir for at least 6 months. Exception: truncal detachment after a new drug → SJS/TEN, stop the drug.

Erysipelas of the lower leg with sharply demarcated, raised, bright red border and…

Sharply demarcated, raised, spreading plaque without purulence → oral penicillin or cephalexin for 5 days, elevation, treat toe web tinea. Exception: purulence → drainage plus MRSA coverage.

Flaccid, thin-roofed bullae and erosions on the trunk with erosive lesions of the…

Oral erosions + flaccid bullae + erosion with lateral pressure → pemphigus vulgaris → intercellular IgG on direct immunofluorescence. Exception: tense bullae without mucosal disease → bullous pemphigoid (linear IgG/C3).

Solitary well-demarcated dusky violaceous plaque with central bulla recurring at the…

Same lesion, same site, every exposure → fixed drug eruption → epidermal CD8+ T-cell-mediated keratinocyte apoptosis. Exception: first exposure may lack the classic recurrence history.

Hypopigmented ash-leaf macules on the trunk, accentuated under Wood lamp

Infantile spasms + tuberous sclerosis → vigabatrin first, with visual field monitoring. Exception: infantile spasms without tuberous sclerosis → ACTH or high-dose prednisolone equally first-line.

Erythematous, edematous urticarial papules and plaques within the abdominal striae,…

Primigravida, third trimester, itchy plaques in striae sparing umbilicus → PUPPP → topical steroids and antihistamines. Exception: periumbilical bullae → biopsy for pemphigoid gestationis.

Digital clubbing

Digital clubbing: lost nail-fold angle — lung cancer, bronchiectasis, cystic fibrosis, cyanotic heart disease, IBD; not COPD.

Hypopigmented, oval ash-leaf macule on the trunk of an infant, accentuated…

Three or more hypomelanotic macules at least 5 mm across constitute one major TSC feature. Infantile spasms heighten suspicion but do not alone complete diagnostic criteria; evaluate additional features and genetic testing.

Multiple dome-shaped, flesh-colored papules with central umbilication and an…

Umbilicated pearly papules with a cheesy core → poxvirus in keratinocytes; observation is acceptable. Exception: large, numerous, or facial lesions in an adult → test for HIV or other immunosuppression.

Well-demarcated oval patch of complete, non-scarring hair loss on the vertex scalp…

Smooth oval patch of complete hair loss + exclamation-point hairs ± nail pits → alopecia areata; intralesional corticosteroid. Exception: scale, black dots, occipital nodes → tinea capitis.

Multiple target lesions with three concentric zones (dusky central bulla, pale…

Recurrent acral target lesions without mucosal disease → erythema multiforme; ask about cold sores. Exception: dusky truncal macules with mucosal erosions → SJS, stop culprit drugs.

Multiple violaceous oval nonblanching plaques and nodules on the lower legs along skin…

Violaceous plaques in HIV → punch biopsy with HHV-8 LANA-1 and Warthin-Starry stains. Exception: once Kaposi sarcoma is confirmed → CD4 count, viral load, and visceral staging.

Hot tub folliculitis: erythematous follicular papules and pustules on buttocks and…

Hot-tub-associated follicular pustules in an otherwise well patient usually resolve without antibiotics. Persistent disease, systemic illness, or immunosuppression warrants evaluation and individualized antimicrobial treatment.

Symmetric grouped small tense vesicles with excoriated crusted erosions on extensor…

Itchy grouped extensor vesicles + papillary neutrophils → dermatitis herpetiformis: check tTG-IgA, start gluten-free diet and dapsone. Exception: check G6PD before dapsone.

Multiple uniform light-brown café-au-lait macules on the trunk with soft pedunculated…

Child meeting NF1 criteria → annual ophthalmologic examination plus yearly blood pressure, growth, and spine checks. Exception: visual loss, proptosis, or disc pallor → MRI of brain and orbits.

Erythematous patches with greasy yellowish scale over the nasolabial folds, eyebrows,…

Greasy yellow scale on nasolabial folds, eyebrows, and scalp → seborrheic dermatitis → topical ketoconazole ± low-potency steroid. Exception: severe or extensive disease warrants HIV testing.

Great toenail with yellow-brown discoloration, subungual hyperkeratosis with crumbly…

Thick, discolored toenails with subungual debris → confirm fungus (KOH, culture, or PAS) before oral terbinafine. Exception: coexisting psoriasis makes confirmation essential; terbinafine can flare it.

Kaposi sarcoma

Kaposi sarcoma: violaceous macules and nodules in HIV (HHV-8) — antiretroviral therapy is the first treatment.

Melanoma skin

A changing suspicious pigmented lesion warrants a complete, adequately deep biopsy with narrow margins when feasible. Elliptical excision, punch excision, or deep saucerization can preserve Breslow-depth assessment.

Neonatal jaundice

Neonatal jaundice: phototherapy thresholds by hour-of-life and risk; jaundice in the first 24 h is always pathologic.

Blood smear2 files

Auer rods AML

Auer rods inside blasts: acute myeloid leukemia — APL (t(15;17)) presents with DIC and is treated with all-trans retinoic acid.

CLL smudge cells

CLL: sheets of small mature lymphocytes with smudge cells in an older adult with lymphocytosis — confirm with flow cytometry; observe until symptomatic.

Ankylosing spondylitis

Ankylosing spondylitis: bilateral sacroiliitis progressing to a bamboo spine — HLA-B27; NSAIDs first, then TNF inhibitors.

Metaphyseal corner fracture

Metaphyseal corner fractures and posterior rib fractures in an infant are highly specific for abuse — skeletal survey under 2 years, report, admit.

Oblique radiograph of the hand showing a fifth metacarpal neck fracture with 35…

Laceration over a knuckle after punching a mouth → irrigate, leave open, give amoxicillin-clavulanate. Exception: severe penicillin allergy → combination covering Eikenella and anaerobes.

Abdominal radiograph showing pneumobilia, an ectopic calcified gallstone in the right…

Small bowel obstruction + biliary air + ectopic calcified density → gallstone ileus; treat with enterolithotomy. Exception: biliary air after sphincterotomy or biliary surgery is not diagnostic.

Gout podagra

Podagra is an acutely inflamed first MTP joint; monosodium urate crystals are needle-shaped and negatively birefringent. Treat the flare with an NSAID, colchicine, or glucocorticoid as appropriate; continue established urate lowering and consider initiation during the flare when indicated.

Paget disease bone

Paget disease: coarsened trabeculae and cortical thickening with an isolated raised alkaline phosphatase — bisphosphonate; watch for osteosarcoma and high-output failure.

Slipped capital femoral epiphysis

Slipped capital femoral epiphysis: 'ice cream falling off the cone' on frog-leg lateral — non-weight-bearing and in-situ pinning; obese adolescents.

Epsilon wave (small deflection immediately following the QRS) and T-wave inversions in…

Exertional syncope, right precordial T-wave inversion with post-QRS deflection, and right ventricular dyskinesia → stop competitive and intense exercise now. Exception: sustained VT or aborted arrest → defibrillator.

Histology1 file

Diffuse sheets of intermediate-sized lymphoid cells with high mitotic index and…

Child + rapidly enlarging ileocecal or jaw mass + starry-sky histology + high LDH and urate → Burkitt lymphoma. Exception: mediastinal mass in an adolescent → lymphoblastic lymphoma.

Lichtenberg figures: branching, fern-like erythematous pattern over the shoulder and…

Lightning strike + fern-like blanching erythema → direct-current asystole with respiratory arrest; ventilate and resuscitate apparently dead victims first. Exception: household alternating current → ventricular fibrillation.

PSY · Step 2 CK

Russell sign: calluses and abrasions over the dorsal MCP joints of the dominant hand

Adolescent purging + K⁺ <3.0 mEq/L, QTc prolongation, or arrhythmia → admit for telemetry and inform parents. Exception: medically stable → outpatient family-based treatment or CBT.

Cushing syndrome

Cushing syndrome: central adiposity, facial plethora, proximal weakness and wide violaceous striae — screen with late-night salivary cortisol, 1-mg dexamethasone test or 24-h urinary cortisol.

Flat-topped violaceous polygonal papules with white lacy Wickham striae on the flexor…

Pruritic purple polygonal flat papules + Wickham striae + oral lacy lesions ± hepatitis C → lichen planus (CD8+ T cells attack basal keratinocytes). Exception: vitiligo also koebnerizes.

Indurated violaceous plaques over the nose, nasal alae, and cheeks (lupus pernio) in a…

Sarcoidosis with impaired lung function or hypercalcemia with kidney injury → oral glucocorticoids. Exception: skin-only disease → hydroxychloroquine or topical therapy; relapse on steroids → add methotrexate.

Firm hyperpigmented nodule extending beyond the margins of the original ear-piercing…

Scar extending beyond the original wound after trauma at a typical site → clinical keloid diagnosis; no biopsy. Exception: no trauma, unusual site, or rapid growth → biopsy.

Actinic cheilitis with diffuse scaling, erythema, and pallor of the lower lip…

Non-healing, indurated, or ulcerated lesion within actinic cheilitis → biopsy before any treatment. Exception: diffuse scaling without focal change → sun protection plus fluorouracil field therapy.

Waxy yellow-brown atrophic plaque with telangiectatic thinned center and a raised…

Waxy yellow-brown shin plaque with atrophic telangiectatic center in diabetes → potent topical steroid to the active border only. Exception: ulceration → wound care and steroid-sparing therapy.

Discoid lupus erythematosus: atrophic hypopigmented plaques with hyperpigmented rims…

Hydroxychloroquine requires baseline fundus, OCT, and fundus autofluorescence assessment. Annual OCT and wide-pattern autofluorescence screening may be deferred for the first five years only in patients without significant risk factors.

Histology3 files

Reed Sternberg cell

Reed-Sternberg cells in the appropriate tissue background and immunophenotype support classical Hodgkin lymphoma; look-alike cells occur in other disorders. Classical cells are typically CD30-positive and CD15-positive.

T-shaped intrauterine device correctly positioned in the fundal endometrial cavity

Distinguish IUD type when interpreting bleeding: copper IUDs can increase menstrual bleeding, whereas levonorgestrel IUDs usually reduce it after early spotting. New or persistent heavy bleeding warrants assessment for pregnancy, displacement, and other uterine causes.

image2 files

MICRO · Step 1

Koplik spots

A second CDC view shows palatal and oropharyngeal Koplik spots.

HEME · Step 1

Petechiae

Perifollicular petechiae; the source does not establish their cause.

ABG and anion-gap interpretation in four decisions

Original educational diagram; interactive labels reveal concise exam facts.

NEURO · Step 1

Crossed brainstem signs: medulla, pons, and midbrain

Original educational diagram; interactive labels reveal concise exam facts.

CV · Step 1

Fetal-to-newborn circulation and shunt direction

Original educational diagram; interactive labels reveal concise exam facts.

Forest plot of pooled risk ratios

Individual confidence intervals cross 1.0, while the pooled diamond lies entirely below 1.0 in this hypothetical example.

RESP · Step 1

From A-a gradient to V/Q, dead space, and true shunt

Original educational diagram; interactive labels reveal concise exam facts.

Time-to-event curves with censoring

Compare the two step-function curves over time and identify the censored observations; Arm A remains above Arm B.

CV · Step 1

Murmurs that change with preload and afterload

Original educational diagram; interactive labels reveal concise exam facts.

Second heart sound during respiration

On expiration, identify P2 followed by A2; on inspiration, the interval narrows. This is a stylized phonocardiogram, not patient audio.

Repetitive nerve stimulation decrement

The fourth CMAP is 12% smaller than the first in this illustrative five-stimulus series.

ROC curve with AUC 0.91

The curve bows toward the upper-left corner and lies above the diagonal no-discrimination line; AUC is 0.91.

RTA types mapped to the nephron

Original educational diagram; interactive labels reveal concise exam facts.

Early-diastolic extra heart sound

The extra low-amplitude sound follows S2 in early diastole. This is a stylized phonocardiogram, not patient audio.

Presystolic extra heart sound

The extra low-amplitude sound occurs immediately before S1, late in diastole. This is a stylized phonocardiogram, not patient audio.

CV · Step 1

Shock profiles at the bedside and catheter

Original educational diagram; interactive labels reveal concise exam facts.

Acid–base: four decisions

A reproducible interpretation sequence

ADH receptors & ANP

Compare water retention, vasoconstriction and natriuresis

BIO · Step 1

Attributable risk: count vs share

See what exposure adds among exposed people

IMM · Step 1

CD markers that change the answer

A compact cell-ID and mechanism matrix

GEN · Step 1

DNA replication & repair

Match the lesion to the repair route

REPRO · Step 1

Early embryo & germ layers

Time the event; then locate its tissue of origin

K⁺, Mg²⁺ & Na⁺ decisions

Separate shifts, losses and water balance

REPRO · Step 1

Endometrial cancer patterns

A contrast map for endometrioid and serous tumors

GI · Step 1

Gut tube, arteries & rotation

One map for foregut, midgut and hindgut

ENDO · Step 1

Incretin drug mechanisms

Separate DPP-4, GLP-1 and SGLT2 targets

NEURO · Step 1

Cerebellum · basal ganglia · thalamus

Locate the circuit from the exam finding

PHARM · Step 1

Cancer drug mechanism map

Connect the target with its signature toxicity

IMM · Step 1

Phagocyte defect sorter

Localize the failure: travel, granules or killing

ENDO · Step 1

Pharyngeal apparatus atlas

Keep arch, pouch and cleft derivatives apart

Renal clearance & FENa

Choose the equation that answers the vignette

Kidney development & anomalies

Two interacting tissues build one kidney

Renal glucose: threshold ≠ Tm

See why glucose appears before all carriers saturate

GEN · Step 1

From DNA to protein

A three-stage map of expression and drug targets

IMM · Step 1

Combined & T-cell deficiencies

Pattern-match the immune compartment

NEURO · Step 1

Visual pathway lesions and field defects

Original educational diagram; interactive labels reveal concise exam facts.

Dermatitis herpetiformis — direct immunofluorescence

In the lower-right panel, granular green IgA fluorescence follows the papillary dermal–epidermal junction.

Bronchial squamous metaplasia — histology

Layered squamous epithelium replaces the ciliated pseudostratified respiratory lining; evaluate atypia separately.

image2 files

Gastric MALT lymphoma — lymphoepithelial lesions

Find small lymphocytes infiltrating and disrupting gastric glands; compare the low-power context with the high-power example.

Schaumann body in a sarcoid granuloma

Identify the laminated inclusion in the giant cell; this plate shows the Schaumann component of the requested granuloma finding.

MSK · Step 1

Full-thickness supraspinatus tear (rotator cuff tear)

MRI shows discontinuity and retraction of supraspinatus tendon fibers with fluid signal gap at the greater tuberosity insertion.

Pleural mesothelioma — chest CT

Trace the mass along the pleural surface rather than treating it as a central lung nodule; the left hemithorax is contracted.

Progressive multifocal leukoencephalopathy — MRI

The T2-bright white-matter lesion reaches the subcortical region; a corresponding T1-dark area appears in the second panel.

image2 files

Ovarian endometrioma — ground-glass ultrasound

The cyst contents have fine, uniform echoes rather than the simple black fluid of a physiologic cyst.