6/20 UWorld Flashcards

1
Q

Describe defect and presentation of Abetalipoproteinemia

A
  • Lack of apoprotein B
    • B48 needed for chylomicron secretion from the intestinal cells
      • Enterocytes fill with chylomicrons that cannot pass into circulation
      • Fat malabsorption, steatorrhea, failure to thrive
      • Night blindness (Vitamin A deficiency)
      • Ataxia
    • B100 needed for LDL reuptake in the liver
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

Histology and treatment of abetalipoproteinemia

A
  • Will see abnormal star-shaped RBCs called acanthocytes (spur cells)
  • Treatment:
    • Vitamin E – will restore apolipoprotiens
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

Defect and presentation in familial hypercholesterolemia

A
  • Increased LDL due to defective or absent LDL receptor
  • Presentation:
    • Accelerated atherosclerosis (early MI), tendon xanthomas, corneal areus
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

Starting substrate and rate limiting enzyme of cholesterol synthesis

A

Starting substrate = acetyl CoA

Rate-limiting step = HMG CoA Reductase (vs. ketogenesis which is HMG CoA synthase)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

Where does fatty acid synthesis occur and what is the rate limiting enzyme

A

Occurs in the cytoplasm

Acetyl CoA carboxylase

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

Location and rate limiting enzyme of Fatty acid degradation

A

Occurs in the mitochondria

Carnitine palmitoyl transferase

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

Deficiencies in what 2 enzymes can lead to hypoketotic hypoglycemia

A

Carnitine palmitoyl transferase deficiency (cannot transport fatty acids into mitochondria for degradation)

Medium chain acyl-CaO dehydrogenase deficiency (no beta-oxidation = cannot break down fatty acids)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

What is the amino acid derivative of serotonin

A

Tryptophan

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

AA derivative of nitric oxide

A

Arginine

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

AA derivative of norepinephrine

A

Phenylalanine (to tyrosine)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

AA derivated of Niacin

A

Tryptophan (remember Hartnup disease)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

What organ does Urea cycle take place in?

A

Liver

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

Rate limiting enzyme for urea cycle

A

carbamoyl phosphate synthetase I (CPSI)

Found in mitochondria

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

AA derivative of porphyrin

A

Glycine

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

Defective enzyme in PKU

A

o Deficiency in phenylalanine hydroxylase, or

o Deficiency in tetrahydrobiopterin cofactor (BH4)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

Treament of PKU

A
  • Decreased phenylalanine intake (proteins, aspartame in artificial sweeteners)
  • Increased tyrosine intake (deficient enzyme was supposed to convert phenylalanine to tyrosine)
  • BH4 supplementation
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

Causes of homocysteinuria

A

o Cystathionine synthase deficiency

o Decreased affinity of cystathionine synthase for B6

o Methionine synthase deficiency

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

What type of receptor does glucagon use?

A

Gs (not part of FLAT ChAMP though)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

Cause and presentation of Hartnup disease

A

o Autosomal recessive deficiency of neutral amino acid transporters

o Leads to decreased absorption of tryptophan, which is the source of niacin (B3)

o Can lead to pellagra-like symptoms

o Treat with high-protein diet and nicotinic acid

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

What vitamin (deficiency or toxicity) is associated with pseudotumor cerebri (idiopathic ICP)

A

Vitamin A toxicity

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

Function of Vitamin E

A

Antioxidant - protects RBC from free radical damage

22
Q

Describe the 3 major diseases caused by thiamine deficiency

A

Thiamine = B1

  • Wernicke-Korsakoff syndrome
    • Triad: confusion, ophthalmoplegia, ataxia
    • Confabulation, personality change, memory loss (permanent)
  • Beriberi = THINK: Ber1Ber1 to remember B1
    • Dry beriberi
      • THINK: nerves
      • Polyneuritis, symmetrical muscle wasting
    • Wet beriberi
      • THINK: heart
      • High-output cardiac failure (dilated cardiomyopathy), edema
23
Q

What vitamin deficiency will cause corneal vascularization

A

B2 Riboflavin

THINK: things are flavorful when you get high (red eyes)

24
Q

Function of Pyridoxine

A

Vitamin B6

  • Converted to pyridoxal phosphate (PLP) and used as a cofactor for transamination (e.g. ALT and AST)
  • Needed for synthesis of cystathionine, heme, niacin (B3), histamine, NTs (serotonin, epinephrine, norepinephrine, dopamine, GABA)
25
Q

Presentation of Vitamin B6 deficiency

A

Convulsions, hyperirritability, peripheral neuropathy

Due to GABA deficiency

26
Q

With what drug should Vitamin B6 be co-administered

A

Isoniazid

27
Q

What type of reactions is Vitamin B7 necessary for

A

Cofactor for carboxylase reactions:

o Pyruvate to oxaloacetate (gluconeogenesis)

o Acetyl CoA to malonyl CoA (fatty acid synthesis)

o Propionyl-CoA to methylmalonyl CoA (fatty acid oxidation)

28
Q

How do you determine the probability of a child being affected by an autosomal recessive disorder if you don’t know the genotype of one of the parents, but are given the allele frequency in the population

A

§ P(affected child) = ¼

§ P(carrier mother) = usually given that the mother is a carrier = 1

§ P(carrier father) = use Hardy-Weinberg

29
Q

PAH is used to estimate what renal value?

A

Renal plasma flow

30
Q

What are the bones of the wrist

A
  • Wrist bones = So Long To Pinky, Here Comes The Thumb
    • Scaphoid, Lunate, Triquetrum, Pisiform, Hamate, Capitate, Trapezoid, Trapezium
31
Q

Differentiate type I from type 2 muscle fibers

A
  • Type 1:
    • Slow twitch
    • Red fibers due to increased mitochondria and myoglobin concentration à increased oxidative phosphorylation à sustained contraction
    • Muscle involving low-level sustained force (e.g. postural maintenance)
    • Proportion increases after endurance training
      • THINK: One slow red ox
  • Type 2:
    • Fast twitch
    • White fibers due to decreased mitochondria and myoglobin concentration à increased anaerobic glycolysis
    • Muscle involved in rapid forceful pulses (e.g. biceps)
    • Proportion increases after weight/resistance training
32
Q

What is the cause and presentation of Osgood-Schlatter disease (OSD)

A

Due to repetitive quadricep contraction (e.g. jumping)

  • Quadricep attached to proximal/superior patella
  • Patellar tenden is attached to distal/inferior patella and inserts at the tibial tuberositiy
  • Reptitive quad contraction (leg extension) causes the proximal patellar tendon to separate from the tibial tubercle, leading to focal pain and swelling at the tibial tuberosity
33
Q

Dynein vs. Kinesin

A

§ Dynein:

  • · Transports from (+) to (-) end of microtubule
  • · Retrograde transport towards the nucleus
    • o THINK: Negative end Near Nucleus
  • · Defective in Kartagener syndrome

§ Kinesin:

  • · Transports from (-) to (+) end of microtubule
  • · Anterograde transport away from nucleus
    • o THINK: Positive end Points to Periphery
34
Q

What is the antibody specific for rheumatoid arthritis (not RF)

A

Anti-CCP (anti-cyclic citrullinated peptide) antibodies

35
Q

Major effect of second hand smoke on children (pre- and post-natal)

A

SIDS

36
Q

Effects of opioid toxicity on BP and HR

A

Bradycardia and hypotension

37
Q

Is Gardnerella vaginalis aerobic/anaerobic gram+/-

A

Anaerobic gram-variable rod

38
Q

MOA of DKA

A

No insulin so no glucose in cells

Cells undergo ketogenesis for energy since there is no glucose

39
Q

Possible hormones secreted by small cell lung cancer

A
  • ADH = SIADH
  • ACTH = Cushing’s
  • Antibodies against pre-synaptic Ca2+ channels = Lambert-Eaton
40
Q

Possible hormones secreted by squamous cell carcinoma of the lung

A

PTH = hypercalcemia

41
Q

Describe bronchoalveolar pneumonia (XR and histology)

A
  • Subtype of adenocarcinoma
  • X-ray shows hazy infiltrates similar to pneumonia
  • Columnar cells grow along pre-existing alveolar septa = apparent “thickening” of alveolar walls
42
Q

Risk factors associated with mesothelioma

A
  • Malignancy of pleura
  • Associated with asbestos
  • No associated with smoking
  • Psammoma bodies
43
Q

Most common locations for lung cancer to mestastasize to

A
  • Adrenals, brain, bone, liver
44
Q

What will you see on CXR in the 3 types of pnuemonia:

Lobar

Bronchopneumonia

Interstitial

A

Lobar = consolidation of an entire lobe

Broncho = scattered, patchy consolidation centered around bronchioles

Interstitial = diffuse infiltrate with increaed lung markings

45
Q

Differentiate between transudative and exudative pleural effusion

A
  • (1) Transudate
    • Low protein content
      • THINK: Transudate is more transparent
    • Due to increased hydrostatic pressure (e.g. CHF or fluid overload) or decreased oncotic pressure (e.g. cirrhosis, nephrotic syndrome)
  • (2) Exudate
    • High protein content, cloudy
    • Due to malignancy, pneumonia, trauma, connective tissue disease
    • Must be drained due to risk of infection
46
Q

Content and caue of lymphatic pleural effusion

A
  • Aka “chylothorax” – milky fluid high in triglycerides
  • Due to thoracic duct rupture or occlusion
47
Q

What is and isn’t drained by the thoracic duct

A

R lymphatic duct drains R side of the body above the diaphragm

Thoracic duct drains everything else into the junction of the L subclavian and internal jugular vein

48
Q

What part of the bone (diaphysis, metaphysis, or epiphysis), do the following tumors occur:

  • Osteochondroma
  • Giant cell tumr
  • Osteosarcoma
  • Ewing sarcoma
A
  • Diaphysis:
    • Osteoid osteoma
    • Ewing sarcoma
  • Metaphysis:
    • Osteosarcoma
    • Osteochondroma
  • Epiphysis:
    • Giant cell tumor
49
Q

What translocation is associated with Ewing sarcoma

A

t(11;22)

THINK: 11 + 22 = 33 (Ewing’s jersey number)

  • Ewing Sarcoma
    • Malignant proliferation of poorly differentiated cells derived from neuroectoderm
    • Arises in the diaphysis of long bones
    • Biopsy reveals small round blue cells resembling lymphocytes
    • XR = onion skin
50
Q

Describe defect and cause of osteopetrosis

A
  • Disorder of bone resorption (osteoclasts) = dense, thickened bones that fracture easily
  • Often due to mutation in carbonic anhydrase II = cannot create acidic environment necessary for bone resorption