4/9 - UWorld

Question 1

What is haptoglobin and what process is it involved in?

Answer 1

Haptoglobin is the protein that binds hemoglobin released during intravascular hemolysis in order to deliver Hb to the spleen

Question 2

What is formed by the urogenital folds in females and males

Answer 2

Female - non-fusion forms labia minora

Male - fusion forms ventral aspect of the penis

Question 3

What is formed by the labioscrotal folds in females and males

Answer 3

Females - labia majora

Males - scrotum

Question 4

What is the triad associated with disseminated gonorrheal infection?

Answer 4

Arthritis, dermatitis, tenosynovitis

Question 5

What is the mechanism of action of IgA?

Answer 5

IgA antibodies usually bind to pili and other membrane proteins involved in bacterial adherence to mucosa, thus inhibiting mucosal colonization by the microorganism

Question 6

What is the function of staphylococcal protein A?

Answer 6

It binds the Fc portion of IgG, preventing complement fixation

Question 7

What hormone is responsible for suppression of lactation in pregnant women?

Answer 7

Progesterone

Question 8

What structures are resposible for progesterone production during pregnancy

Answer 8

Corpus luteum in first trimester

Placent in second and third trimesters

Question 9

What structures are responsible for b-hCG production?

Answer 9

Syncytiotrophoblasts

b-hCG functions to maintain corpus luteum until placenta takes over for estrogen and progesterone synthesis

b-hCG reaches highest levels at 9 weeks, and then drops to very low levels once corpus luteum degenerates

Question 10

What enzyme will take over fructose metabolism in fructokinase deficiency (essential fructosuria)?

Answer 10

Hexokinase

Question 11

What is the deficient enzyme in fructose intolerance?

Answer 11

Aldolase B

Question 12

HMO (health maintenence organization) vs. PPO (preferred provider organization) vs. POS (point of service)

Which has lowest monthly premiums, requires PCP referral, allows outside provider network?

Answer 12

Question 13

Will methylmalonic acid be increased or decreased in B12 deficiency?

Answer 13

Increased

Methylmalonic acid is converted to Succinyl CoA using B12 as a cofactor

Question 14

C1 inhibitor deficiency causes inappropriate activation of complement cascade and …. ?

Answer 14

Increased bradkinin

C1 inhibitor blocks kallikrein-induced conversion of kininogen to bradykinin

Question 15

What are Langhan cells and what are the the result of?

Answer 15

Activated macrophages (epithelioid cells) can form Langhans giant cells, which characteristically have multiple nuceli organized peripherally in the shape of a horseshoe

These cells are a non-specific finding in granulomatous conditions (e.g. tuberculosis)

The macrophages are originally stimulated by CD4+ Th1 cells

Question 16

What type of anemia will be seen in lead poisoning?

Answer 16

Microcytic anemia

Lead inhibits the heme synthesis pathway due to defective protoporphyrin synthesis (sideroblastic anemia)

Question 17

What are common clinical findings of lead poisoning?

Answer 17

GI (abd pain, constipation, anorexia)

Neuro (cognitive defects, peripheral neuropathy)

Hematologic (anemia)

Question 18

What will be seen in peripheral blood smear vs. bone marrow in lead poisoning

Answer 18

Bone marrow - ring sideroblasts

Peripheral blood smear - basophilic stippling

Question 19

Describe the clinical presentation of congenital hypothyroidism

Answer 19

Lethargy, hoarse cry, poor feeding, constipation, jaundice, dry skin, large fontanelle, umbilical hernia, edema

Congenital hypothyroidism is one of the most common causes of preventable intellectual disability

Aka Cretinism (6 P’s):

Pot-bellied, pale, puffy-faced child with protruding umbilicus, protuberant tongue, and poor brain development

Question 20

What is the defect in osteogenesis imperfecta?

Answer 20

Defect in type I collagen synthesis

Question 21

What is a common mutation leading to osteopetrosis?

Answer 21

Carbonic anyhdrase II mutation

Leads to loss of acidic environment necessary for bone resorption

Question 22

Describe lab findings in Paget disease of the bone (calcium, phosphate, PTH, alkaline phosphatase)

Answer 22

Isolated elevated alkaline phosphatase (due to end stage where osteoblasts are trying to lay down bone)

All other levels will be normal

Question 23

Complications of Paget’s disease

Answer 23

High output cardiac failure (due to increased blood flow from formation of arteriovenous shunts in bone)

Osteosarcoma (end-stage osteoblasts at risk for mutation)

Question 24

Features of Gardner syndrome

Answer 24

Familial adenomatous polyps

Osteomas/soft tissue tumors (osteoma of facial bone)

Impacted/supernumerary teeth

Question 25

Symptoms of hepatic encephalopathy

Answer 25

Tremor (asterixis)

Slurring of speech

Somnolence

Vomiting

Cerebral edema

Blurring of vision

Question 26

Causes of hepatic encephalopathy

Answer 26

Liver disease (urea cycle occurs in hepatocytes)

Urea cycle enzyme deficiency (ornithine transcarbamylase is the most common deficiency)