Path Rotation facts

Question 1

Causes of SIADH

Answer 1

Paraneoplastic syndrome from Small Cell Carcinoma

CNS disorder / Head trauma

Pulmonary disease (pneumonia)

Drugs (cyclophosphamide)

Question 2

Tennis rackets on electron microscopy

Answer 2

Birbeck granules

Langerhans cells (dendritic cells found in skin, derived from bone marrow, present antigen to naive T cells)

CD1a+
S100+

Review Pathoma

Question 3

S100+

Answer 3

Schwannoma
Melanoma
Langerhans cells

Question 4

hearing loss / tinnitus
S100+
bilateral involvement associated w/ neurofibromatosis type 2

Answer 4

Schwannoma

Question 5

vomit / diarrhea / epigastric pain

uritcarial rashes on feet, buttocks, waist

Answer 5

Strongyloides

steroid use –> Septic Shock!

Tx: Ivermectin
Albendazole

Question 6

Eosinophilic pneumonia

Answer 6

Loffler’s syndrome 2/2 strongyloides

Question 7

Older male, steatorrhea, foamy macrophages in intestinal lamina propria

Cardiac symptoms / Arthralgias / Neurologic symptoms

PAS+

Answer 7

“Foamy Whipped cream in CAN”

Whipple Disease – Tropheryma whippelii

Question 8

Hyperpigmented mouth, feet, hands, genitalia

Hamartomatous GI polyps

Answer 8

Peutz-Jeghers Syndrome

AD trait

Increased risk for Breast and GI cancers

Question 9

Vitamin A

name / function / deficiency / excess

Answer 9

Retinol

constituents of visual pigments, essential for normal differentiation of epithelial cells into pancreatic cells and mucus-secreting cells, prevents squamous metaplasia, USED TO TREAT MEASLES & AML

Night blindness (nyctalopia); dry scaly skin (xerosis cutis); corneal degeneration (keratomalacia); Bitot spots on conjunctiva; immunosuppression

Acute toxicity - n/v, vertigo, blurred vision
Chronic toxicity - alopecia, dry skin, hepatic toxicity and enlargement, arthralgias, and pseudotumor cerebri
Teratogenic (cleft palate, cardiac abnormalities), THEREFORE A NEGATIVE PREGNANCY TEST AND TWO FORMS OF CONTRACEPTION ARE REQUIRED BEFORE ISOTRETINOIN PRESCRIBED

Question 10

Vitamin B1

name / function / deficiency

Answer 10

Thiamine

Thiamine pyrophosphate (TPP), a cofactor for several dehydrogenase enzyme reactions:

• Pyruvate dehydrogenase (links glycolysis to TCA cycle)
• alpha-ketoglutarate dehydrogenase (TCA cycle)
• Transketolase (HMP shunt)
• Branched-chain ketoacid dehydrogenase

Impaired glucose breakdown –> ATP depletion worsened by glucose infusion; highly aerobic tissue affected first (BRAIN, HEART).
Wenicke-Korsakoff syndrome and beriberi. Seen in malnutrition and alcoholism. Diagnosis made by increase in RBC transketolase activity following B1 administration.

Question 11

Vitamin B2

name / function / deficiency

Answer 11

Riboflavin

Components of flavins FAD and FMN, used as cofactors in redox reactions (succinate dehydrogenase reaction in TCA cycle) “FAD and FMN derived from riboFlavin (B2 = 2ATP)”

Cheilosis (inflammation of lips, scaling and fissures at the corners of the month), Corneal vascularization
“2 C’s of B2”

Question 12

Vitamin B3

name / function / deficiency / excess

Answer 12

Niacin

Constituents of NAD and NADP (used in redox reactions). Derived from tryptophan. Synthesis requires vitamin B2 and B6. Used to treat dyslipidemia; lowers level of VLDL and raises levels of HDL

Glossitis. Severe deficiency leads to PELLAGRA, which can be caused by Hartnup disease, malignant carcinoid syndrome, and INH.
3 D’s of B3: Diarrhea, Demenita, Dermatitis

Facial flushing (induced by prostaglandin, not histamine; can avoid by taking aspirin with niacin), hyperglycemia, hyperuricemia

Question 13

Hartnup Disease

Answer 13

AR, deficiency of neutral amino acid (tryptophan) transporters in proximal renal aminoaciduria and decrease absorption from the gut –> decrease tryptophan for conversion to niacin –> pellagra-like symptoms.

Tx: high protein diet & nicotinic acid

Question 14

Vitamin B5

name / function / deficiency

Answer 14

Pantothenic acid

Essential component of coenzyme A and fatty acid synthesis

Dermatitis, Enteritis, Alopecia, Adrenal insufficiency

Question 15

Vitamin B6

name / function / deficiency

Answer 15

Pyridoxine

Converted to pyridoxal phosphate (PLP), a cofactor used in transamination (AST and ALT), decarboxylation, glycogen phosphorylase. Synthesis of cystathionine, heme, niacin, histamine, and neurotransmitters including serotonin, epinephrine, norepinephrine, dopamine, and GABA.

Convulsions, hyperirritability, periperhal neuropathy (induced by INH and OCPs), sideroblastic anemias 2/2 impaired hemoglobin synthesis and iron excess.

Question 16

Vitamin B12

name / function / deficiency

Answer 16

Biotin

Cofactor for carboxylation enzymes (add a 1-carbon group):

• Pyruvate carboxylase: pyruvate (3C) –> oxaloacetate (4C)
• Acetyl-CoA carboxylase: acetyl-CoA (2C) –> malonyl-CoA (3C)
• Propionyl-CoA carboxylase: propionyl-CoA (3C) –> methylmalonyl-CoA (4C)

Relatively rare deficiencies, Dermatitis, Alopecia, Enteritis. Caused by antibiotic use of excessive ingestion of raw egg whites

“Avidin in egg whites avidly binds biotin”

Question 17

Vitamin B9

name / function / deficiency

Answer 17

Folate

Converted to tetrahydrofolic acid (THF), a coenzyme for 1-carbon transfer/methylation reactions. Important for the synthesis of nitrogenous bases in DNA and RNA. ABSORBED IN JEJUNUM.

Macrocytic, megaloblastic anemia; hypersegmented polymorphonuclear cells (PMNs); glossitis; NO NEURO deficits.
LABS: increased homocysteine, normal methylmalonic acid. Most common vitamin deficiency in US. Seen in alcoholism and pregnancy. Deficiency caused by Phenytoin, Sulfonamides, Methotrexate.

Question 18

Vitamin B12

name / function / deficiency

Answer 18

Cobalamin

Cofactor for methionine synthase (transfers CH3 groups as methylcobalamin) and methylmalonyl-CoA mutase

Macrocytic, megaloblastic anemia; hypersegmented PMNs; paresthesias and subacute combined degeneration (dorsal columns, lateral corticospinal tracts, Spinocerebellar tracts) due to abnormal myelin. Associated with increased serum homocysteine and methylmalonic acid levels. Prolonged deficiency –> irreversible nerve damage.

Question 19

Vitamin C

name / function / deficiency / excess

Answer 19

Ascorbic Acid

Antioxidant; also facilitates iron absorption by reducing it to Fe2+ state. Necessary for hydroxylation of proline and lysine in collagen synthesis. Necessary for dopamine beta-hydroxylase, which converts dopamine to NE

Scurvy - swollen gums, bruising, petechiae, hemarthrosis, anemia, poor wound healing, perifollicular and subperiosteal hemorrhages, “corkscrew” hair. Weakened immune response.

n/v/d, fatigue, calcium oxalate nephrolithiasis. Can increase risk of iron toxicity in predisposed individuals (those with transfusions, hereditary hemochromatosis)

Question 20

Vitamin D

name / function / deficiency / excess

Answer 20

D2 = ergocalciferol - ingested from plants
D3 = cholecalciferol - consumed in milk, formed in sun-exposed skin (stratum basale)
25-OH D3 = storage form
1,25-(OH)2 D3 = calcitriol, active form

Increase intestinal absorption of calcium and phosphate, increase bone mineralization at low levels, increase bone resorption at higher levels

Rickets - in children (bone pain and deformity)
Osteomalacia - in adults (bone pain and muscle weak)
Hypocalcemic tetany
Breast fed infants should be fed oral vitamin D
Deficiency exacerbated by low sun exposure, pigmented skin, prematurity

Hypercalcemia, hypercalciuria, loss of appetite, stupor
Seen in granulomatous disease (increase activation of vitamin D by epithelioid macrophages)

Question 21

Vitamin E

name / function / deficiency

Answer 21

Tocopherol
Tocotrienol

Antioxidant (protects RBCs and membranes from free radical damage)
Can enhance anticoagulation effects of warfarin

Hemolytic anemia, acanthocytosis, muscle weak, posterior column, spinocerebellar tract demyelination

Question 22

Vitamin K

name / function / deficiency

Answer 22

Phytomenadione
Phylloquinone
Phytonadione

Cofactor for the gamma-carboxylation of glutamic acid residues on various proteins required for blood clotting. Synthesized by intestial flora

Neonatal hemorrhage with increased PT and PTT but normal bleeding time (neonates have sterile intestines and are unable to synthesize vitamin K). Can also occur after prolonged used of broad-spectrum antibiotics.

Question 23

Zinc

function / deficiency

Answer 23

Mineral essential for the activity of 100+ enzymes. Important in the formation of zinc fingers (transcription factor motif).

Delayed wound healing, hypogonadism, decrease adult hair (axillary, facial, pubic), dysgeusia, anosmia, acrodermatitis enteropathica. May predispose to alcoholic cirrhosis.