Mixed 1

Question 1

Acute Synovitis

[Causes, Dx]

Answer 1

> Causes: septic arthritis (gonococcal, nongonococcal), crystal arthropathy (gout), hemarthrosis, rheumatic dse.
Dx: diagnostic arthrocentesis; crystal analysis, cell count, culture, gram stain; blood culture (septic arthritis).

Question 2

Acute synovitis w/ fever and/or leukocytosis: why is it important?

Answer 2

Emergency, expedite evaluation.

Possibly due to septic arthritis – loss of joint, long-term disability.

Question 3

Treacher-Collins syndrome

[Pathogenesis, SSx]

Answer 3

Caused by abnormal dev. of 1st and 2nd pharyngeal arches.
Craniofacial abnormalities (mandibular, maxillary, zygomatic hypoplasia).
Airway compromise (DOB), feeding difficulty.
Conductive hearing loss (abnormal ossicles).

Question 4

Nicotinic acid (Niacin)
[MOA, toxicity} 
Tx for what? How do you reduce SE?

Answer 4

Tx for hyperlipidemia (Inc. HDL, dec. LDL); Releases prostaglandins.
SE: flushing, warmth, itching.
*To reduce SE, give Aspirin about 30 mins before niacin admin (or use slow-release niacin, or take w/ food)

Question 5

Anticipation
Define.
Found in what genetic conditions?

Answer 5

Tendency for clinical sx to worsen and/or occur earlier in subsequent generations.
Assctd w/ trinucleotide repeat d/o: Fragile X syndrome (CGG), Huntington dse (CAG), Myotonic dystrophy, Friedreich ataxia.

Question 6

Genomic Imprinting
Define.
Examples.

Answer 6

Selective inactivation of genes of either maternal or paternal origin – gene of a chromosome is epigenetically silenced for entire life of organism, reset only during egg/sperm formation.
(Ex. Prader-Willi syndrome, Angelman syndrome)

Question 7

Prader-Willi syndrome

[SSx]

Answer 7

Paternal chromosome has deleted regions (no expression); Maternal chromosome has imprinted genes (silenced).
Hyperphagia, obesity,
Hypotonia, hypogonadism,
Intellectual disability.

Question 8

Angelman syndrome

[SSx]

Answer 8

Maternal chromosome has deleted regions (no expression); Paternal chromosome has imprinted regions (silenced).
Inappropriate laughter ("happy puppet"), Ataxia,
Severe intellectual disability, seizures.

Question 9

How do HIV patients become resistant to HAART drugs? (2)

Answer 9

HIV-1 has high mutability.

Pol mutations: structural changes in HIV-1 reverse transcriptase – enzyme resistant to NRTI and NNRTI.

Question 10

Pyruvate dehydrogenase deficiency.

What happens? Diet?

Answer 10

Pyruvate is converted to lactate by lactate dehydrogenase (instead of into acetyl-COA).
>Must give Ketogenic diet: leucine, lycine – lessens lactic acidosis.
>Glucogenic and ketogenic: phenylalanine, isoleucine, tryptophan.

Question 11

Tetrahydrobiopterin (BH4) deficiency.

What is BH4? What happens in BH4 deficiency?

Answer 11

*BH4: cofactor for 5HT, tyrosine, DOPA (dopamine, NE, epi) synthesis.
BH4 deficiency due to dihydropteridine reductase defect – phenylketonuria – disrupted neural and glial dev – neuro deterioration.

Question 12

How do gallstones become a complication of total parenteral nutrition (TPN)?

Answer 12

Normally, fat/amino acids in duodenum induce release of CCK – gallbladder contraction.
With TPN, there’s no enteral stimulation – dec. CCK release – biliary stasis.

Question 13

Fragile X syndrome

[Px, Classic findings]

Answer 13

Expansion of trinucleotide repeats (CGG) in FMR1 gene.

Findings: macrocephaly, long face; large forehead, jaw, chin, ears; Macroorchidism (large testes).

Question 14

Fragile X syndrome.

[Findings on Folate-deficient medium, cytogenetic studies]

Answer 14

> Folate-deficient medium: no stain in area of inc. repeats.

>Cytogenetic studies: gap near tip of long arm of X chromosome.

Question 15

Histoplasma capsulatum

[Location, History, SSx]

Answer 15

Dimorphic fungus; spores found in bird and bat droppings (exploring caves, cleaning bird cages).
Endemic to Mississippi and Ohio river basins.
Affects lungs and RES – lymphadenopathy, hepatosplenomegaly.

Question 16

Lead poisoning

[Occupational exposure, Labs]

Answer 16

> Exposure: lead paint, batteries, ammo, construction.
Labs: microcytic anemia, normal iron studies; basophilic stippling (lead inhibits 5’nucleotidase – ribosome aggregation – can’t degrade RNA).

Question 17

MC cause of Sudden cardiac death?

Answer 17

Malignant ventricular arrhythmias

Ventricular fibrillation is most frequent cause w/in first 48 hrs ff. acute MI

Question 18

How does C. diphtheriae obtain its virulence?

Answer 18

Bacteriophage carrying Tox gene (codes for diphtheria AB exotoxin) infects host bacterium, integrates its genome into bacterium’s genome (lysogenization).

Question 19

Ankylosing spondylitis
[SSx]
How do you monitor progression?

Answer 19

Ankylosis involving sacroiliac and apophyseal joints of spine – pain in lower back, hip and buttock; peripheral arthritis.
Also includes enthesitis, ascending aortitis, anterior uveitis.
Monitor via Hypoventilation due to limited chest wall expansion.

Question 20

Treatment for B-blocker overdose

Answer 20

> Overdose: dec. heart contractility, bradycardia, AV block – dec. CO.
Tx: Glucagon – GPCR on myocytes – adenylate cyclase – inc. cAMP – inc. intracellular Ca during contraction – inc. SA node firing (inc. HR, contractility).

Question 21

hCG is most similar to which hormone? What effects can it have on this hormones receptors? hCG is secreted by what tumors?

Answer 21

hCG has identical alpha-subunit to TSH, FSH, LH, and a similar beta-subunit to TSH.
It can bind to TSH receptor – paraneoplastic hyperthyroidism.
Secreted by testicular germ cell tumors, gestational trophoblastic dse.

Question 22

What drug(s) may cause hemorrhagic cystitis? Pathogenesis? SSx? Prevention?

Answer 22

Cyclophosphamide (ifosfamide).
Toxic Acrolein metabs – cell death and necrosis of uroepithelial cells.
Frequent urination, progressive hematuria, suprapubic pain.
Prevention: aggressive hydration, co-admin w/ Mesna (inactivates toxic metabs of chemo drugs).