Classic Labs/findings part 1

Question 1

Colonies of mucoid Pseudomonas in lungs

Answer 1

Cystic fibrosis (autosomal recessive mutation in CFTR
gene -->  fat-soluble vitamin deficiency and mucous plugs)

Question 2

Decreased AFP in amniotic fluid/maternal serum

Answer 2

Down syndrome, Edwards syndrome

Question 3

Increased β-hCG,

Decreased PAPP-A on first trimester screening

Answer 3

Down syndrome

Question 4

Increased serum homocysteine, increased mehtylmalonic acid, decreased folate

Answer 4

Vitamin B12 deficiency

Question 5

Anti-histone antibodies

Answer 5

Drug-induced SLE (eg, hydralazine, isoniazid, phenytoin, TNF-α inhibitors)

Question 6

Low T cells, low PTH, low Ca2+, absent thymic shadow on CXR

Answer 6

Thymic aplasia (DiGeorge syndrome, velocardiofacial syndrome)

Question 7

Large granules in phagocytes, immunodeficiency

Answer 7

Chédiak-Higashi disease (congenital failure of phagolysosome formation)

Question 8

Recurrent infections, eczema, thrombocytopenia

Answer 8

Wiskott-Aldrich syndrome

Question 9

Optochin sensitivity

Answer 9

Sensitive: S pneumoniae;
Resistant: viridans streptococci (S mutans, S sanguis)

Question 10

Novobiocin response

Answer 10

Sensitive: S epidermidis;
Resistant: S saprophyticus

Question 11

Bacitracin response

Answer 11

Sensitive: S pyogenes (group A);
Resistant: S agalactiae (group B)

Question 12

Branching gram ⊕ rods with sulfur granules

Answer 12

Actinomyces israelii

Question 13

Hilar lymphadenopathy, peripheral granulomatous lesion

in middle or lower lung lobes (can calcify)

Answer 13

Ghon complex (1° TB: Mycobacterium bacilli)

Question 14

“Thumb sign” on lateral neck x-ray

Answer 14

Epiglottitis (Haemophilus influenzae)

Question 15

Bacteria-covered vaginal epithelial cells

Answer 15

“Clue cells” (Gardnerella vaginalis)

Question 16

Dilated cardiomyopathy with apical atrophy

Answer 16

Chagas disease (Trypanosoma cruzi)

Question 17

Atypical lymphocytes, heterophile antibodies

Answer 17

Infectious mononucleosis (EBV infection)

Question 18

Eosinophilic intranuclear inclusions with perinuclear

halo

Answer 18

Cells infected by herpesviruses (eg, HSV, VZV, CMV)

Question 19

“Steeple” sign on frontal CXR

Answer 19

Croup (parainfluenza virus)

Question 20

Eosinophilic inclusion bodies in cytoplasm of

hippocampal and cerebellar neurons

Answer 20

Negri bodies of rabies

Question 21

Ring-enhancing brain lesion on CT/MRI in AIDS

Answer 21

Toxoplasma gondii, CNS lymphoma

Question 22

Psammoma bodies

Answer 22

Meningiomas, papillary thyroid carcinoma,
mesothelioma, papillary serous carcinoma of the
endometrium and ovary

Question 23

“Delta wave” on ECG, short PR interval, supraventricular

tachycardia

Answer 23

Wolff-Parkinson-White syndrome (bundle of Kent

bypasses AV node)

Question 24

“Boot-shaped” heart on x-ray

Answer 24

Tetralogy of Fallot (due to RVH)

Question 25

Rib notching (inferior surface, on x-ray)

Answer 25

Coarctation of the aorta

Question 26

Granuloma with giant cells after pharyngeal infection

Answer 26

Aschoff bodies (rheumatic fever)

Question 27

Electrical alternans (alternating amplitude on ECG)

Answer 27

Cardiac tamponade

Question 28

Enlarged thyroid cells with ground-glass nuclei with central clearing

Answer 28

“Orphan Annie” eyes nuclei (papillary carcinoma of the

thyroid)

Question 29

“Brown” tumor of bone

Answer 29

Hyperparathyroidism or osteitis fibrosa cystica (deposited hemosiderin from hemorrhage gives brown color)

Question 30

Hypertension, hypokalemia, metabolic alkalosis

Answer 30

1° hyperaldosteronism (eg, Conn syndrome)

Question 31

Mucin-filled cell with peripheral nucleus

Answer 31

“Signet ring” (gastric carcinoma)

Question 32

Anti-transglutaminase/anti-gliadin/anti-endomysial

antibodies

Answer 32

Celiac disease (diarrhea, weight loss)

Question 33

Narrowing of bowel lumen on barium x-ray

Answer 33

“String sign” (Crohn disease)

Question 34

“Lead pipe” appearance of colon on abdominal imaging

Answer 34

Ulcerative colitis (loss of haustra)

Question 35

Thousands of polyps on colonoscopy

Answer 35

Familial adenomatous polyposis (autosomal dominant, mutation of APC gene)