Look-Alike Splitter

Look-alike diseases side by side. One highlighted tell clinches each.

the tell clinches that row missed 2+ times ★ most tested benign → lethal row order Miss List →

Cardio-pulm

Elevated JVP with clear lungsREPEAT-MISS INSIDEchronic → emergent

Both/all: Edema or low output, lungs clear, heart undilated — three run a high JVP, the impostor does not

Cirrhosis with ascitesJVP is NORMAL — that kills every cardiac optionParacentesis for SAAG
Restrictive cardiomyopathyThick walls with biatrial enlargement; amyloid gives low voltageCardiac MRI, serum free light chains
Constrictive pericarditis ★Pericardial knock, septal bounce, calcification; Kussmaul shared with restrictionPericardiectomy
Cardiac tamponadePulsus paradoxus, electrical alternans, no Kussmaul signEcho, pericardiocentesis

Shock 3-5 days after MIREPEAT-MISS INSIDEleast → most lethal

Both/all: New hypotension days 3-5 post-infarct with fresh murmur or flash edema — one member breaks that timing

Right ventricular infarctionHypotension AT presentation with inferior MI, clear lungs, no murmurIV fluids, avoid nitrates
Ventricular septal rupture ★Palpable thrill plus RA-to-RV oxygen step-upUrgent surgical repair
Papillary muscle ruptureSoft or absent murmur with high PCWPSurgery, IABP as bridge
Free wall ruptureSudden PEA arrest with tamponade physiologyPericardiocentesis, emergency surgery

Wide-complex tachycardiaREPEAT-MISS INSIDEbenign → lethal

Both/all: Wide QRS tachycardia; the wrong drug here kills the patient

Atrial fibrillation with aberrancyIrregular but constant QRS morphology matching known bundle branch blockRate control
Monomorphic VT ★Uniform QRS with AV dissociationStable: IV amiodarone. Unstable: synchronized cardioversion
Preexcited atrial fibrillation (WPW)Irregular with varying QRS width, rates above 200Procainamide; never AV nodal blockers
Polymorphic VT / torsadesTwisting axis with QTc >500 msMagnesium, unsynchronized shock, stop QT drugs

Heart block or VT in a young adultREPEAT-MISS INSIDEbenign → lethal

Both/all: Nonischemic VT or high-grade AV block with normal coronaries — one member gives VT only, never block

Viral myocarditisPost-viral drop in EF without arrhythmia stormFull GDMT; NSAIDs worsen it
Cardiac sarcoidosis ★Uveitis or hilar nodes; a NORMAL biopsy is expectedCardiac MRI or PET
Arrhythmogenic RV cardiomyopathyEpsilon wave, LBBB-morphology VT triggered by exerciseCardiac MRI, ICD
Giant-cell myocarditisFulminant heart failure with refractory VTSteroids plus transplant evaluation

Pulmonary hypertension: which groupREPEAT-MISS INSIDEGroup 1→4

Both/all: Dyspnea with elevated PA pressure on echo and RV strain

Group 1 PAHPCWP ≤15 with PVR >2 Wood units, lungs normalVasoreactive → high-dose CCB; else PDE5i/ERA
Group 2 (left heart disease) ★PCWP >15 — the wedge overrules the storyTreat left heart; vasodilators cause edema
Group 3 (COPD/ILD)Hypoxemic parenchymal lung disease drives itOxygen and treat the lung
Group 4 CTEPHPrior VTE; mismatched segmental perfusion defects on V/QV/Q scan, not CT angiography

Fibrotic or nodular lung on HRCTREPEAT-MISS INSIDEreversible → fatal

Both/all: Chronic dyspnea, low DLCO, abnormal HRCT — three restrict, the cystic one obstructs

Hypersensitivity pneumonitisBird or farm exposure, UPPER-lobe centrilobular nodules, normal IgERemove the antigen
SarcoidosisBilateral hilar adenopathyEBUS-TBNA of the node; exclude TB first
LymphangioleiomyomatosisThin-walled CYSTS, not fibrosis; young women, chylothoraxVEGF-D, sirolimus
Idiopathic pulmonary fibrosis ★Clubbing, bibasilar crackles, subpleural honeycombingHRCT establishes it; antifibrotics

Eosinophilia with pulmonary infiltratesREPEAT-MISS INSIDEsteroid-responsive → steroid-harmed

Both/all: Peripheral eosinophilia plus lung infiltrates, usually with asthma

Chronic eosinophilic pneumoniaPERIPHERAL pleural-based infiltrates sparing the centerCorticosteroids
ABPA ★Brown mucus plugs and migrating infiltratesAspergillus skin testing first
EGPANasal polyps, eosinophils >10%, neuropathy, p-ANCA/MPOSteroids; ANCA panel
StrongyloidesEndemic origin, GI pain, symptoms FLARE on steroidsSerology; two negative stools exclude nothing

Systolic murmur that moves with maneuversbenign → lethal

Both/all: Systolic murmur in an ambulatory patient, with or without syncope

Mitral valve prolapseClick moves earlier and murmur lengthens on standingEcho
Atrial septal defectFixed split S2, RBBB, right axis — never LVHEcho with bubble study
Aortic stenosisSoftens on standing; carotid parvus et tardusTTE before any noncardiac surgery
Hypertrophic cardiomyopathy ★Louder on standing with NO click; asymmetric septum ≥15 mmEcho; ICD only for high-risk features

Exertional leg painvascular → nonvascular

Both/all: Leg, buttock or thigh pain brought on by walking

Aortoiliac disease (Leriche)Buttock/hip pain with erectile dysfunction and femoral bruitCT angiography
Peripheral arterial disease ★Calf pain, ABI <0.9, or exercise ABI drop >0.15Exercise ABI if resting ABI 0.9-1.3
Neurogenic claudicationWorse DOWNHILL, relieved leaning forward, pulses normalMRI lumbar spine
Statin myopathyConstant proximal ache, not exertionalCK, TSH, vitamin D

Pleural effusion: name the fluidbenign → lethal

Both/all: Unilateral effusion, thoracentesis already done

Benign asbestos effusionEosinophils >50%, 10-15 years after exposureObserve; self-resolving
ChylothoraxMilky fluid with triglycerides >110Look for lymphoma obstructing the duct
Tuberculous effusionLymphocytic exudate with ADA >40Pleural biopsy; fluid AFB is low yield
Malignant effusion ★Bloody exudate; pH ≥7.3 predicts low cytology yieldContrast chest CT next

Syncopebenign → lethal

Both/all: Transient loss of consciousness with spontaneous full recovery

Vasovagal syncope ★Prodromal warmth or nausea while uprightTilt-table only if recurrent and injurious
Carotid sinus hypersensitivityTriggered by shaving, dressing or head turningCarotid massage; pace if asystole >3 s
Outflow obstruction (HCM or AS)Exertional syncope with a systolic murmurEchocardiography
Long QT / arrhythmic syncopeQTc >500 ms; syncope on startle or swimming, exam normalBeta-blocker for LQT1/2; ICD after syncope

Resistant hypertensioncommonest → rarest

Both/all: BP above goal on three drugs including a diuretic

Obstructive sleep apnea ★Neck >43 cm (men) / >40 cm (women), snoring, somnolencePolysomnography, then CPAP
Primary hyperaldosteronismHYPOKALEMIA alongside the resistant hypertensionAldosterone-to-renin ratio first
Renal artery stenosisFlash pulmonary edema or creatinine rise on an ACE inhibitorACE inhibitor plus diuretic; stent only if refractory
Coarctation of the aortaWeak delayed femoral pulses, rib notching, Turner syndromeCT or MR angiography

Regular narrow-complex tachycardia at ~150adenosine: unmasks → terminates

Both/all: Regular narrow QRS tachycardia; irregularity would mean AF or MAT instead

Sinus tachycardiaRate varies with fever, pain or volume statusTreat the driver, not the rate
Atrial flutter with 2:1 block ★Rate locked near 150; adenosine unmasks flutter waves, never convertsCavitricuspid isthmus ablation after diltiazem fails
AVNRTRetrograde P buried in QRS: pseudo-R prime V1, RP <70 msVagal maneuvers, then adenosine
Orthodromic AVRT (WPW)Discrete retrograde P, RP >70 ms; delta returns in sinusAdenosine; accessory pathway ablation

GI-liver

Abnormal liver enzymesREPEAT-MISS INSIDEhepatitic → cholestatic

Both/all: Transaminase or alkaline phosphatase elevation on routine labs

NAFLD ★AST:ALT <1 with metabolic syndromeExclude hep B/C and iron; weight loss
Autoimmune hepatitisHepatitic pattern with high IgG and smooth muscle antibodyCorticosteroids
Alcoholic hepatitisAST:ALT >2 with fever and jaundiceMaddrey >32 → steroids
Primary biliary cholangitisALP/GGT far above transaminases, with pruritusAMA; ursodeoxycholic acid

New ascitesREPEAT-MISS INSIDESAAG high → low

Both/all: Abdominal distension with fluid; paracentesis in hand

Cirrhotic portal hypertension ★SAAG ≥1.1 with ascitic protein <2.5Spironolactone 100 mg + furosemide 40 mg
Heart failureSAAG ≥1.1 with ascitic protein ≥2.5Diurese, echocardiography
Budd-Chiari syndromeOCPs, tender hepatomegaly, NORMAL serum albuminDoppler the hepatic veins
Peritoneal carcinomatosis or TBSAAG <1.1Cytology, ADA

Dysphagiaproximal → distal

Both/all: Trouble swallowing, with or without weight loss

Zenker diverticulumOropharyngeal with gurgling and halitosisBarium esophagram; EGD can perforate the pouch
Eosinophilic esophagitisConcentric rings and linear furrows, food impactionBiopsy ≥15 eosinophils/hpf
Achalasia ★Bird-beak barium; solids AND liquids from the startManometry; squamous cancer risk
PseudoachalasiaAge >60, symptoms <6 months, weight lossEGD first

Chronic diarrhea with malabsorptionmalabsorptive → functional

Both/all: Months of loose stools — three malabsorb with weight loss, the fourth never does

Celiac disease ★Jejunal loss of iron, folate, vitamin D; itchy elbows/kneesHLA-DQ2/DQ8 if already gluten-free
GiardiasisHiker or camper with greasy stoolsStool microscopy, metronidazole
Small intestinal bacterial overgrowthDiabetic autonomic neuropathy, watery NOCTURNAL stools, flatulenceCarbohydrate breath test, rifaximin
Irritable bowel syndromePain RELIEVED by defecation, normal labsFiber, antispasmodics

Heme-onc

FlushingREPEAT-MISS INSIDEbenign → lethal

Both/all: Episodic flushing, often with diarrhea, palpitations or spells

Systemic mastocytosisDarier sign, anaphylactoid spellsSerum tryptase
Carcinoid syndrome ★Telangiectasias and RIGHT-sided valve fibrosis; requires liver mets24-hour 5-HIAA; octreotide
Medullary thyroid carcinomaThyroid nodule with RET/MEN2 family historyCalcitonin; exclude pheo before surgery
PheochromocytomaParoxysmal hypertension with headache and diaphoresisFractionated metanephrines

Falling platelets on heparinREPEAT-MISS INSIDEType 1→2, then mimics

Both/all: Thrombocytopenia in a hospitalized patient receiving heparin

Type 1 HITDay 1-4, nadir >100,000, no clotContinue heparin, observe
Type 2 HIT ★Day 5-10 fall over 50%, often with new thrombosisStop ALL heparin including LMWH; argatroban
ITPIsolated thrombocytopenia with petechiae, no heparin timingTest HIV and HCV before treating
Sepsis / DICLow fibrinogen with prolonged coagulation studiesTreat the source

High hematocritREPEAT-MISS INSIDEEPO low → high → mimic

Both/all: Elevated hemoglobin or hematocrit on a routine CBC — one mimic runs a normal hematocrit

Polycythemia vera ★LOW serum EPO; splenomegaly, aquagenic pruritus, JAK2Phlebotomy plus aspirin
Hypoxic secondary erythrocytosisHIGH EPO with low oxygen saturationCheck sats before ordering any CT
EPO-secreting tumorHIGH EPO with normal oxygen saturationRenal and hepatic imaging
Essential thrombocythemiaBurning red feet, platelets 540,000, hematocrit NORMALLow-dose aspirin

Leukocytosis with splenomegalyREPEAT-MISS INSIDEbenign → lethal

Both/all: High white count with an abnormal smear — three enlarge the spleen, the reactive one does not

Leukemoid reactionBasophils 0% with toxic granulation and Döhle bodiesFind the infection
CLLMature small lymphocytes with smudge cellsPeripheral flow cytometry
Chronic myeloid leukemia ★BASOPHILIA with a left-shifted myeloid spectrum, Philadelphia chromosomeBCR-ABL TKI first line
Primary myelofibrosisLeukoerythroblastic smear with a dry tapBone marrow CORE biopsy

Monoclonal protein or unexplained proteinuriaREPEAT-MISS INSIDEbenign → lethal

Both/all: Older adult with anemia, renal impairment and protein on dipstick or SPEP

MGUSM-spike <1.5 g/dL, IgG type, normal light-chain ratioObserve
AA amyloidosisLongstanding RA or chronic infection driving itTreat the underlying inflammation
Light-chain myeloma ★Grams of protein with a NEGATIVE dipstick; SPEP negativeUrine immunofixation and serum free light chains
AL amyloidosisNephrotic proteinuria with bland sediment, macroglossia, easy bruisingFat pad or marrow biopsy

Schistocytes with thrombocytopenianormal coags → abnormal

Both/all: Microangiopathy: anemia, low platelets, schistocytes, often AKI

TTP ★NORMAL coagulation studies with severe thrombocytopeniaPlasma exchange; never transfuse platelets
HUSFollows bloody diarrhea; AKI dominatesSmear; antibiotics and antimotility agents worsen it
HELLP syndromePregnancy with high LFTs and hypertensionDelivery
DICLOW fibrinogen with prolonged PT and aPTTTreat the trigger, replace factors

Hemolytic anemia: read the CoombsCoombs positive → negative

Both/all: Anemia with high LDH and reticulocytes, low haptoglobin, indirect bilirubin

Warm autoimmune hemolytic anemia ★Coombs IgG-positive with SPHEROCYTES; CLL backgroundCorticosteroids
Cold agglutinin diseaseC3-positive/IgG-negative, RBC clumping, spurious MCV after mycoplasmaWarming and rituximab, not steroids
PNHCoombs-NEGATIVE with portal vein thrombosis and pancytopeniaFlow cytometry CD55/CD59; vaccinate before eculizumab
G6PD deficiencyBite cells after an oxidant; level falsely normal acutelyRecheck the level in 2-3 months

Bleeding with a normal platelet countcongenital → acquired

Both/all: Mucosal or surgical bleeding; palatal petechiae would instead mean low platelets

von Willebrand disease ★Lifelong mucocutaneous bleeding since childhoodDDAVP; VWF concentrate for type 2B/3
Vitamin K deficiencyLow factor VII with a NORMAL factor VVitamin K
Uremic platelet dysfunctionKidney failure; transfused platelets fail in uremic plasmaDesmopressin
Acquired factor VIII inhibitorLong aPTT that does NOT correct on mixingRecombinant factor VIIa now, steroids later

ID

Tick-season febrile illnessREPEAT-MISS INSIDEbenign → lethal

Both/all: Fever, headache and myalgias after outdoor exposure

Lyme diseaseErythema migrans; late monoarticular knee arthritisDoxycycline
Ehrlichiosis / anaplasmosis ★Leukopenia, thrombocytopenia, high LFTs, NORMAL hemoglobinDoxycycline
BabesiosisHEMOLYSIS weeks after a transfusion; Maltese crossSmear; it never grows in culture
Rocky Mountain spotted feverRash starting on wrists and ankles, moving centrallyDoxycycline immediately

Pneumonia failing its antibioticREPEAT-MISS INSIDEatypical → cavitary

Both/all: Community pneumonia not improving on a beta-lactam

MycoplasmaCold agglutinins with RBC clumping in a young patientAzithromycin or doxycycline
Legionella ★Hyponatremia, relative bradycardia, high LFTsUrine antigen; add azithromycin or levofloxacin
Lung abscessDependent cavity with an AIR-FLUID LEVELAmpicillin-sulbactam; no drainage needed
TuberculosisWeeks of weight loss with an upper-lobe cavityThree sputum AFB, airborne isolation

Bacterial meningitis: what to coverREPEAT-MISS INSIDEGram stain, then viral

Both/all: Fever and neck stiffness — three give neutrophilic CSF, the impostor is lymphocytic and viral

Pneumococcus ★Gram-positive diplococciVancomycin + ceftriaxone; dexamethasone continued 4 days
ListeriaGram-positive BACILLI, age >50 or immunosuppressedAdd ampicillin; resistant to all cephalosporins
MeningococcusPurpura fulminans with DIC, often asplenicCeftriaxone; DROPLET precautions 24 hours
HSV encephalitisLymphocytic CSF with temporal-lobe seizuresAcyclovir

Ring-enhancing brain lesionCD4 low → normal

Both/all: Seizure or focal deficit with an enhancing lesion on imaging

Primary CNS lymphomaCD4 <50 with a single periventricular lesionCSF EBV PCR, brain biopsy
Toxoplasmosis ★CD4 <100 with multiple lesionsPyrimethamine + sulfadiazine + LEUCOVORIN
Septic embolusNormal CD4 with a new murmurEchocardiography, blood cultures
NeurocysticercosisCALCIFIED lesions, endemic originMRI with contrast; stool exam is useless

Cavity or nodule in an immunocompromised lungbenign → lethal

Both/all: Fever and cough with a pulmonary nodule, cavity or infiltrate

CoccidioidomycosisSouthwest travel, thin-walled cavity, EOSINOPHILIASerology (not urine antigen)
Pneumocystis pneumoniaDiffuse ground glass with a NEGATIVE galactomannanTMP-SMX; steroids if hypoxemic
Invasive aspergillosis ★HALO sign with a positive galactomannanVoriconazole
MucormycosisDKA with periorbital swelling and sinus tendernessEmergent debridement plus liposomal amphotericin

Red painful legbenign → lethal

Both/all: Warm erythematous leg brought in as cellulitis

Stasis dermatitisBILATERAL, afebrile, rust-brown hemosiderinTopical triamcinolone plus compression, never antibiotics
Nonpurulent cellulitisSpreading erythema with no pus = group A strepCephalexin
Purulent cellulitis / abscess ★Abscess, furuncle or carbuncle = S. aureus/MRSAI&D; TMP-SMX if ≥2 cm
Deep vein thrombosisSwelling with calf tenderness, no sharp erythema borderCompression ultrasound; repeat if D-dimer high

Renal-lytes

Non-anion-gap acidosishypokalemic → hyperkalemic

Both/all: Low bicarbonate with a normal anion gap

GI bicarbonate loss ★NEGATIVE urine anion gap (diarrhea, laxatives)Replace volume and bicarbonate
Type 1 distal RTAHypokalemia with sicca and urine SG 1.001Lip biopsy for Sjögren; bicarbonate
Type 4 RTAHyperkalemia with NO culprit drug; hyporeninemic diabetic CKDFludrocortisone, low-potassium diet
High-dose TMP-SMXHyperkalemia starting with the drug, plus false creatinine riseRecheck potassium, adjust dose

High anion gap acidosisgap widest → narrowest

Both/all: Elevated anion gap in an acutely ill patient

Lactic acidosis ★Gap of 41 with metformin plus AKIStop metformin; dialysis if severe
DKAKetones; the gap closes before the glucose doesAt glucose ≤200 add dextrose, continue insulin
Salicylate toxicityGap acidosis PLUS respiratory alkalosis, pH 7.40Alkalinize the urine
Uremic acidosisCKD alone — the gap rarely exceeds 20Dialysis planning

Blood in the urineglomerular → no RBCs

Both/all: Dipstick or gross hematuria

IgA nephropathy ★SYNPHARYNGITIC gross hematuria with dysmorphic RBCsBiopsy if proteinuria >500 mg/day
Post-infectious glomerulonephritisLatency of 1-3 weeks with LOW C3Supportive care
Urologic malignancyPAINLESS gross hematuria in an older adultCT urography plus cystoscopy
RhabdomyolysisDipstick blood with NO RBCs on microscopyCheck CK; FENa can be falsely low

AKI after a procedure or new drugsoonest → latest

Both/all: Creatinine rise in a hospitalized patient

Contrast nephropathyRise at 24-48 hours, then recoversPrevent with IV isotonic saline
Cholesterol embolismLivedo reticularis, BLUE TOES, eosinophilia one week post-cathSupportive; statin
Acute interstitial nephritis ★Culprit drug with WBC casts and sterile pyuriaStop the drug; steroids only if no improvement
Retroperitoneal fibrosisCaliceal dilation WITHOUT ureteral dilation, plus DVTCT abdomen, stenting

Endocrine

Low testosteroneREPEAT-MISS INSIDELH low → high

Both/all: Fatigue and low libido with a low morning total testosterone

Secondary (central) hypogonadism ★Low LH with NORMAL prolactin: opioids, obesity, OSA, hemochromatosisMRI if testosterone <200 under age 65
ProlactinomaElevated prolactin, with or without galactorrheaCabergoline first, never surgery first
Androgen deprivation therapyProstate cancer treatment; 20% fracture in 5 yearsDXA, calcium and vitamin D
Primary testicular failureHIGH LH and FSHConfirm with a repeat morning level, then replace

Hypercalcemiasevere acute → mild chronic

Both/all: Elevated serum calcium on a chemistry panel

Malignancy / PTHrP ★Calcium >13, acute onset, very symptomaticSaline + calcitonin + zoledronic acid together
Multiple myelomaAnemia with sensory ataxia and bone painSerum immunofixation
Granulomatous diseaseSarcoid with high 1,25-dihydroxyvitamin DCorticosteroids
Primary hyperparathyroidismMild (<11), chronic, asymptomatic, PTH not suppressedRepeat calcium and PTH

Which diabetes is thisobese → lean

Both/all: Hyperglycemia in an adult, classification drives therapy

Type 2 diabetes ★Obesity and insulin resistance without ketosisMetformin; GLP-1 agonist if weight loss needed
Ketosis-prone type 2Obese adult in DKA with NEGATIVE GAD/islet/insulin antibodiesTaper the insulin off
LADALean adult (BMI 21) with autoimmunityGAD65 antibodies, then insulin
Pancreatic cancer diabetesThin patient whose diabetes suddenly worsens with weight lossCT abdomen

Neuro-psych

Weakness with reduced reflexesREPEAT-MISS INSIDEacute → chronic

Both/all: Subacute limb weakness — three drop the reflexes, the myopathy keeps them

Guillain-Barré syndrome ★ASCENDING symmetric weakness with global areflexiaLP: high protein, normal WBC; IVIG or plasmapheresis
West Nile poliomyelitisFever with ASYMMETRIC flaccid weakness, downgoing plantarsSupportive; West Nile IgM
Diabetic amyotrophyPainful proximal L2-L4 wasting with weight loss and orthostasisGlycemic control, physical therapy
Inclusion-body myositisFINGER-FLEXOR plus quadriceps weakness with dysphagiaMuscle biopsy; steroid-refractory

Fever with rigidity and altered mental statusREPEAT-MISS INSIDEfastest → slowest onset

Both/all: Hyperthermia, autonomic instability and confusion on psychotropics

Malignant hyperthermiaStarts minutes after a volatile anesthetic or succinylcholineDantrolene
Serotonin syndromeCLONUS and hyperreflexia, rapid onset, diarrheaCyproheptadine
Anticholinergic toxicityDry skin and mydriasis with NO rigidityPhysostigmine
Neuroleptic malignant syndrome ★LEAD-PIPE rigidity, slow onset, CK >1000Stop the antipsychotic; dantrolene + bromocriptine

Acute vision lossREPEAT-MISS INSIDEemergent → recoverable

Both/all: Sudden or subacute loss of vision, usually monocular

Giant cell arteritis ★Age >50 with jaw claudication and very high ESRHigh-dose steroids BEFORE the biopsy
Retinal detachmentFlashes, floaters and a peripheral FIELD defectUrgent ophthalmology; normal fundus does not exclude it
Malignant hypertensionIndistinct swollen disc margins with severe hypertensionControlled BP lowering
Optic neuritisPAINFUL with eye movement, RAPD, normal or swollen discMRI brain for MS

Recurrent headacheREPEAT-MISS INSIDEbenign → lethal

Both/all: Repeated headaches without a persistent focal deficit

Paroxysmal hemicraniaMore than 5 attacks/day, each 2-30 minutesIndomethacin — the response is diagnostic
Cluster headache15-180 minutes with autonomic tearing, often nocturnalHigh-flow oxygen
Idiopathic intracranial hypertensionObese young woman, worse LYING FLAT, empty sellaLP opening pressure >250 mm H2O
Subarachnoid hemorrhage ★Abrupt thunderclap with meningismusCT then LP; screen the ADPKD family

Sensory ataxia and dorsal column lossreversible → fatal

Both/all: Loss of vibration and proprioception with a positive Romberg

B12 deficiency ★Post-gastric-bypass or metformin, plus memory changeB12 and methylmalonic acid
Tabes dorsalisARGYLL ROBERTSON pupil and ascending aortitisTreponemal EIA; IV penicillin G
Multiple myelomaNormocytic anemia with hypercalcemiaSerum immunofixation, not MRI
Paraneoplastic sensory neuronopathy (anti-Hu)Lung mass, NORMAL MRI, sensory loss including the faceAnti-Hu antibody; CT chest for SCLC

Rheum-derm

ANCA-associated vasculitisREPEAT-MISS INSIDEPR3 → MPO → both

Both/all: Systemic vasculitis hitting sinuses, lungs or kidneys

Granulomatosis with polyangiitis ★c-ANCA/PR3 with DESTRUCTIVE sinus disease and cavitary nodulesSteroids plus rituximab; limited GPA is ANCA-negative 30%
EGPAAsthma and nasal polyps with eosinophils >10%p-ANCA/MPO; steroids
Microscopic polyangiitisp-ANCA pulmonary-renal disease with NO granulomas or asthmaSteroids plus rituximab
Levamisole-adulterated cocaineRetiform purpura on the EARLOBES, leukopenia, BOTH MPO and PR3Stop cocaine

Palpable purpuraREPEAT-MISS INSIDEbenign → severe → impostor

Both/all: Non-blanching palpable purpura with a normal platelet count

Isolated leukocytoclastic vasculitisSkin only, negative workup, no ulcerationSymptomatic care
IgA vasculitis ★Abdominal pain plus hematuria in the same patientSkin biopsy establishes it
Cryoglobulinemic vasculitisLOW C4 with a high rheumatoid factorHepatitis C serologies
Polyarteritis nodosa (purpura excludes it)Medium vessel: livedo, nodules, ulcers — never palpable purpuraAngiography or nerve biopsy; check HBV

Acute monoarthritisREPEAT-MISS INSIDEsynovial WBC high → low

Both/all: One hot swollen joint, tap already done

Septic arthritis ★Synovial WBC >50,000Cultures, IV antibiotics, drainage
GoutNegatively birefringent needles; tophi sit on DIP jointsNSAID, colchicine or steroid now; allopurinol later
CPPDChondrocalcinosis; under age 55 screen hemochromatosisIron, TIBC, ferritin
Hydroxyapatite (Milwaukee shoulder)Destructive shoulder, rusty effusion, NO crystals under polarized lightAlizarin red stain

Chronic polyarthritis: read the jointsREPEAT-MISS INSIDEMCP → DIP

Both/all: Months of hand and wrist pain with swelling

Rheumatoid arthritis ★Symmetric MCP/PIP/WRIST synovitis SPARING the DIPsMethotrexate; add TNF inhibitor, never swap it out
Hemochromatosis arthropathy2nd-3rd MCP hook osteophytes with chondrocalcinosisFerritin and transferrin saturation
Hand osteoarthritisDIP osteophytes and first CMC involvementTopical diclofenac if ≥65 or HTN/CKD/CHF
Psoriatic arthritisDIP disease, nail pitting, pencil-in-cup, normal ESR and RFSkin exam; DMARD or biologic

Hip and outer-thigh painREPEAT-MISS INSIDEdeep → superficial

Both/all: Pain around the hip on walking or lying down

Hip osteoarthritis ★Groin pain on internal rotation; x-ray shows joint-space lossX-ray, physical therapy
Avascular necrosisGroin pain, NORMAL x-ray and ESR/CRP, steroids or transplantMRI; never a steroid injection
Trochanteric bursitisPoint tenderness over the lateral trochanter, worse lying on itPhysical therapy, injection
Meralgia parestheticaPure SENSORY burning over the outer thighWeight loss, loosen belts

Forefoot painREPEAT-MISS INSIDEdistal → proximal

Both/all: Pain in the ball of the foot with walking

Morton neuroma ★WEB-SPACE marble with a Mulder clickMetatarsal pad, injection
Metatarsal stress fractureShaft tenderness or pain on axial toe loadingMRI if x-ray negative
Tarsal tunnel syndromeBurning SOLE pain with Tinel behind the medial malleolusNerve conduction study

Drug eruption weeks after a new drugREPEAT-MISS INSIDEbenign → lethal

Both/all: Rash appearing days to weeks after starting a medication

Fixed drug eruptionRecurs at the SAME site with each exposureAvoid the drug
AGEPSterile pustules within 48 hours of the drugStop drug, supportive
DRESS ★Facial edema, eosinophilia, transaminitis, mucosa SPARED, 2-8 weeksStop drug; send CBC diff and LFTs
SJS/TENDusky coalescing bullae with ORAL and conjunctival erosionsStop drug, burn-unit level care

Facial rashREPEAT-MISS INSIDElocal → systemic

Both/all: Erythema across the cheeks and nose

Acne vulgarisCOMEDONES presentTopical retinoid
Steroid rosaceaFollowed topical steroid use on the faceStop the steroid
Papulopustular rosacea ★INVOLVES the nasolabial folds; pustules, telangiectasias, no comedonesOral doxycycline
SLE malar rashSPARES the nasolabial folds; oral ulcersANA, anti-dsDNA

Blisters on the handsREPEAT-MISS INSIDEbenign → lethal

Both/all: Vesicles or bullae on the hands or sun-exposed skin

Impetiginized eczemaHONEY crust with pustulesMupirocin
Erythema multiformeTARGET lesions, HSV-triggeredTreat or suppress HSV
Porphyria cutanea tardaMilia and scarring on sun-exposed DORSAL hands, high ferritinTest for hepatitis C; phlebotomy
Eczema herpeticum ★MONOMORPHIC punched-out vesicles on eczematous skinValacyclovir; never steroids

Proximal muscle complaintsstiffness → true weakness

Both/all: Shoulder and hip girdle pain or weakness in an older adult

Polymyalgia rheumatica ★Stiffness WITHOUT true weakness, normal CKPrednisone 12.5-25 mg/day
Statin myopathyAche on a statin, constant rather than positional or exertionalCK, TSH, vitamin D
Dermatomyositis / polymyositisTrue weakness with high CK, heliotrope or Gottron papulesPrednisone 1 mg/kg plus cancer screening
Inclusion-body myositisAsymmetric finger flexors and quadriceps, steroid-refractoryMuscle biopsy