Memorize Key Lab Findings Flashcards
DECREASED AFP in amniotic fluid/maternal serum
Down syndrome or other chromosomal abnormalities
Large granules in phagocytes, immunodeficiency
Chédiak-Higashi disease (congenital failure of phagolysosome formation)
Recurrent infections, eczema, thrombocytopenia
Wiskott-Aldrich syndrome
Branching gram ⊕ rods with sulfur granules
Actinomyces israelii
Optochin sensitivity
Sensitive: S pneumoniae; resistant: viridans streptococci (S mutans, S sanguis)
Novobiocin response
Sensitive: S epidermidis; resistant: S saprophyticus
Bacitracin response
Sensitive: S pyogenes (group A); resistant: S agalactiae (group B)
Streptococcus bovis bacteremia
Colon cancer
Hilar lymphadenopathy, peripheral granulomatous lesion in middle or lower lung lobes (can calcify)
Ghon complex (1° TB: Mycobacterium bacilli)
Bacteria-covered vaginal epithelial cells
“Clue cells” (Gardnerella vaginalis)
Ring-enhancing brain lesion on CT/MRI in AIDS
Toxoplasma gondii, CNS lymphoma
Cardiomegaly with apical atrophy
Chagas disease (Trypanosoma cruzi)
Heterophile antibodies
Infectious mononucleosis (EBV)
Intranuclear eosinophilic droplet-like bodies
Cowdry type A bodies (HSV or VZV)
Eosinophilic globule in liver
Councilman body (viral hepatitis, yellow fever), represents hepatocyte undergoing apoptosis
“Steeple” sign on frontal CXR
Croup (parainfluenza virus)
Eosinophilic inclusion bodies in cytoplasm of hippocampal and cerebellar neurons
Negri bodies of rabies
Atypical lymphocytes
EBV
Enlarged cells with intranuclear inclusion bodies
“Owl eye” appearance of CMV
“Thumb sign” on lateral neck x-ray
Epiglottitis (Haemophilus influenzae)
“Delta wave” on ECG, short PR interval, supraventricular tachycardia
Wolff-Parkinson-White syndrome (Bundle of Kent bypasses AV node)
“Boot-shaped” heart on x-ray
Tetralogy of Fallot (due to RVH)
Rib notching (inferior surface, on x-ray)
Coarctation of the aorta
Heart nodules (granulomatous)
Aschoff bodies (rheumatic fever)
Electrical alternans (alternating amplitude on ECG)
Pericardial tamponade
Hypertension, hypokalemia, metabolic alkalosis
1° hyperaldosteronism (Conn syndrome)
Enlarged thyroid cells with ground-glass nuclei with central clearing
“Orphan Annie” eyes nuclei (papillary carcinoma of the thyroid)
Antineutrophil cytoplasmic antibodies (ANCAs)
Microscopic polyangiitis and eosinophilic granulomatosis with polyangiitis (MPO-ANCA/p-ANCA); granulomatosis with polyangiitis (Wegener; PR3ANCA/c-ANCA); primary sclerosing cholangitis (MPOANCA/p-ANCA)
Mucin-filled cell with peripheral nucleus
“Signet ring” (gastric carcinoma)
Anti-transglutaminase/anti-gliadin/anti-endomysial antibodies
Celiac disease (diarrhea, weight loss)
Narrowing of bowel lumen on barium x-ray
“String sign” (Crohn disease)
“Lead pipe” appearance of colon on abdominal imaging
Ulcerative colitis (loss of haustra)
Thousands of polyps on colonoscopy
Familial adenomatous polyposis (autosomal dominant, mutation of APC gene)
“Apple core” lesion on barium enema x-ray
Colorectal cancer (usually left-sided)
Eosinophilic cytoplasmic inclusion in liver cell
Mallory body (alcoholic liver disease)
Triglyceride accumulation in liver cell vacuoles
Fatty liver disease (alcoholic or metabolic syndrome)
“Nutmeg” appearance of liver
Chronic passive congestion of liver due to right heart failure or Budd-Chiari syndrome
Antimitochondrial antibodies (AMAs)
1° biliary cirrhosis (female, cholestasis, portal hypertension)
Low serum ceruloplasmin
Wilson disease (hepatolenticular degeneration; KayserFleischer rings due to copper accumulation)
Migratory thrombophlebitis (leading to migrating DVTs and vasculitis)
Trousseau syndrome (adenocarcinoma of pancreas or lung)
Basophilic nuclear remnants in RBCs
Howell-Jolly bodies (due to splenectomy or nonfunctional spleen)
Hypochromic, microcytic anemia
Iron deficiency anemia, lead poisoning, thalassemia (fetal hemoglobin sometimes present)
Basophilic stippling of RBCs
Lead poisoning or sideroblastic anemia
“Hair on end” (“Crew-cut”) appearance on x-ray
β-thalassemia, sickle cell disease (marrow expansion)
Hypersegmented neutrophils
Megaloblastic anemia (B12 deficiency: neurologic symptoms; folate deficiency: no neurologic symptoms)
Antiplatelet antibodies
Idiopathic thrombocytopenic purpura
High level of d-dimers
DVT, PE, DIC
Giant B cells with bilobed nuclei with prominent inclusions (“owl’s eye”)
Reed-Sternberg cells (Hodgkin lymphoma)
Sheets of medium-sized lymphoid cells with scattered pale, tingible body–laden macrophages (“starry sky” histology)
Burkitt lymphoma (t[8:14] c-myc activation, associated with EBV; “starry sky” made up of malignant cells)
Lytic (“punched-out”) bone lesions on x-ray
Multiple myeloma
Monoclonal antibody spike
Multiple myeloma (usually IgG or IgA) Monoclonal gammopathy of undetermined significance (MGUS consequence of aging)
Waldenström (M protein = IgM) macroglobulinemia Primary amyloidosis
Stacks of RBCs
Rouleaux formation (high ESR, multiple myeloma)
Azurophilic peroxidase ⊕ granular inclusions in granulocytes and myeloblasts
Auer rods (AML, especially the promyelocytic [M3] type)
WBCs that look “smudged”
CLL (almost always B cell)
“Tennis racket”-shaped cytoplasmic organelles (EM) in Langerhans cells
Birbeck granules (Langerhans cell histiocytosis)
“Brown” tumor of bone
Hyperparathyroidism or osteitis fibrosa cystica (deposited hemosiderin from hemorrhage gives brown color)
Raised periosteum (creating a “Codman triangle”)
Aggressive bone lesion (eg, osteosarcoma, Ewing sarcoma, osteomyelitis)
“Soap bubble” in femur or tibia on x-ray
Giant cell tumor of bone (generally benign)
“Onion skin” periosteal reaction
Ewing sarcoma (malignant small blue cell tumor)
Anti-IgG antibodies
Rheumatoid arthritis (systemic inflammation, joint pannus, boutonniere and swan neck deformities)
Rhomboid crystals, ⊕ birefringent
Pseudogout (calcium pyrophosphate dihydrate crystals)
Needle-shaped, ⊝ birefringent crystals
Gout (monosodium urate crystals)
Increased uric acid levels
Gout, Lesch-Nyhan syndrome, tumor lysis syndrome, loop and thiazide diuretics
“Bamboo spine” on x-ray
Ankylosing spondylitis (chronic inflammatory arthritis: HLA-B27)
Antinuclear antibodies (ANAs: anti-Smith and antidsDNA)
SLE (type III hypersensitivity)
Anti-topoisomerase antibodies
Diffuse systemic scleroderma
Keratin pearls on a skin biopsy
Squamous cell carcinoma
Antihistone antibodies
Drug-induced SLE (eg, hydralazine, isoniazid, phenytoin, procainamide)
Bloody or yellow tap on lumbar puncture
Subarachnoid hemorrhage
Yellowish CSF
Xanthochromia (eg, due to subarachnoid hemorrhage)
Eosinophilic cytoplasmic inclusion in neuron
Lewy body (Parkinson disease and Lewy body dementia)
Extracellular amyloid deposition in gray matter of brain
Senile plaques (Alzheimer disease)
Depigmentation of neurons in substantia nigra
Parkinson disease (basal ganglia disorder: rigidity, resting tremor, bradykinesia)
Protein aggregates in neurons from hyperphosphorylation of tau protein
Neurofibrillary tangles (Alzheimer disease) and Pick bodies (Pick disease)
Silver-staining spherical aggregation of tau proteins in neurons
Pick bodies (Pick disease: progressive dementia, changes in personality)
Pseudopalisading tumor cells on brain biopsy
Glioblastoma multiforme
Circular grouping of dark tumor cells surrounding pale neurofibrils
Homer-Wright rosettes (neuroblastoma, medulloblastoma)
“Waxy” casts with very low urine flow
Chronic end-stage renal disease
RBC casts in urine
Glomerulonephritis
“Tram-track” appearance of capillary loops of glomerular basement membranes on light microscopy
Membranoproliferative glomerulonephritis
Nodular hyaline deposits in glomeruli
Kimmelstiel-Wilson nodules (diabetic nephropathy)
Podocyte fusion or “effacement” on electron microscopy
Minimal change disease (child with nephrotic syndrome)
“Spikes” on basement membrane, “dome-like” subepithelial deposits
Membranous nephropathy (nephrotic syndrome)
Anti–glomerular basement membrane antibodies
Goodpasture syndrome (glomerulonephritis and hemoptysis)
Cellular crescents in Bowman capsule
Rapidly progressive crescentic glomerulonephritis
“Wire loop” glomerular capillary appearance on light microscopy
Diffuse proliferative glomerulonephritis (usually seen with lupus)
Linear appearance of IgG deposition on glomerular and alveolar basement membranes
Goodpasture syndrome
“Lumpy bumpy” appearance of glomeruli on immunofluorescence
Poststreptococcal glomerulonephritis (due to deposition of IgG, IgM, and C3)
Necrotizing vasculitis (lungs) and necrotizing glomerulonephritis
Granulomatosis with polyangiitis (Wegener; PR3-ANCA/ c-ANCA) and Goodpasture syndrome (anti–basement membrane antibodies)
Thyroid-like appearance of kidney
Chronic pyelonephritis (usually due to recurrent infections)
WBC casts in urine
Acute pyelonephritis
Renal epithelial casts in urine
Intrinsic renal failure (eg, ischemia or toxic injury)
hCG elevated
Choriocarcinoma, hydatidiform mole (occurs with and without embryo, and multiple pregnancy)
Dysplastic squamous cervical cells with “raisinoid” nuclei and hyperchromasia
Koilocytes (HPV: predisposes to cervical cancer)
Psammoma bodies
Meningiomas, papillary thyroid carcinoma, mesothelioma, papillary serous carcinoma of the endometrium and ovary
Disarrayed granulosa cells arranged around collections of eosinophilic fluid
Call-Exner bodies (granulosa cell tumor of the ovary)
“Chocolate cyst” of ovary
Endometriosis (frequently involves both ovaries)
Mammary gland (“blue domed”) cyst
Fibrocystic change of the breast
Glomerulus-like structure surrounding vessel in germ cells
Schiller-Duval bodies (yolk sac tumor)
Rectangular, crystal-like, cytoplasmic inclusions in Leydig cells
Reinke crystals (Leydig cell tumor)
Thrombi made of white/red layers
Lines of Zahn (arterial thrombus, layers of platelets/ RBCs)
Hexagonal, double-pointed, needle-like crystals in bronchial secretions
Bronchial asthma (Charcot-Leyden crystals: eosinophilic granules)
Desquamated epithelium casts in sputum
Curschmann spirals (bronchial asthma; can result in whorled mucous plugs)
“Honeycomb lung” on x-ray or CT
Interstitial pulmonary fibrosis
Colonies of mucoid Pseudomonas in lungs
Cystic fibrosis (autosomal recessive mutation in CFTR gene fat-soluble vitamin deficiency and mucous plugs)
Iron-containing nodules in alveolar septum
Ferruginous bodies (asbestosis: chance of lung cancer)
Bronchogenic apical lung tumor on imaging
Pancoast tumor (can compress cervical sympathetic chain and cause Horner syndrome)