2015.04.12 (2) Flashcards Preview

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Flashcards in 2015.04.12 (2) Deck (52)
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1
Q

Mucicarmine stain

A

Detects polysaccharide capsule of Cryptococcus neoformans.

Red-stained capsule is a major virulence factor.

2
Q

Cryptococcus neoformans

A

Polysaccharide capsule that stains with mucicarmine.

Seen in tissue as round yeast cells with narrow-based buds.

Affects immunocompromised patients and is transmitted via respiratory route. May cause pulmonary disease.

Methenamine silver (GMS) and India ink staining is used too.

Subacute or chronic meningoencephalitis is most common presentation.

3
Q

Round yeast with broad-based budding and a thick, doubly-reflective wall

A

Blastomyces dermatitidis

causes lung disease and disseminated mycosis

4
Q

Histoplasma capsulatum

A

dimorphic fungus that causes tb-like pulmonary disease. causes disseminated mycosis in immunocompromised.

Found intracellulary in tissue (within macrophages) as small, ovoid, budding yeast cells

5
Q

Coccioides immitis

A

causes lung disease in immunocompetent people and disseminated mycosis in immunocompromised individuals.

large, irregulary sized, thick-walled spherules that contain small, round endospores.

6
Q

Enteropeptidase/Enterokinase

A

enzyme produced in the duodenum required for activation of trypsinogen into trypsin.

Enteropeptidase deficiency causes diarrhea, growth retardation and hypoproteinemia

7
Q

Pulsatile GnRH agonists adminstration

A

Stimulates FSH and LH for treatment of infertility.

8
Q

Constant (nonpulsatile) GnRH adminstration

A

Causeds down-regulation of GnRH receptors, which suppresses LH and FSH secretion.

Usually syntheteic analogue (leuprolide) is used.

Used for treatment of precocious puberty, prostate cancer, endometriosis, dysfunctional uterine bleeding (where suppression of HPA ovarian axis is indicated)

9
Q

Pleural effusion vs. Atelectasis

A

Opacified lung with lung volume loss (atelectasis) causes trachea deviation towards the opacified lung.

Trachea deviation away from opacified lung occurs with pleural effusion.

10
Q

Severe allergic asthma

A

Frequent exacerbations requiring oral steroids. Patients are initially treated with inhaled steroids and long-acting beta-agonists. However, symptom control is difficult because these patients are frequently resistant and need oral steroids.

Anti-IgE antibodies given as subcutaneous injection have been shown to be effective in patients with moderate-to-severe allergic asthma.

Omalizumab (recombinant humanized IgG1 monoclonal antibody that binds with IgE to inhibit IgE activity) is effective in reducing dependency on both oral and inhaled steroids.

11
Q

Visceral Obesity

A

Visceral fat is fat surround internal organs and has a much stronger correlation with insulin resistance than subcutaneous fat.

Measuring waist-to-hip ratio indirectly measures the viseral fat.

12
Q

Pulmonary abscesses

A

local suppurative collections within lung parenchyma that result in necrosis of the surrounding lung tissue.

destruction due to release of lysosomal enzymes from neutrophils and macrophages (initially to digest offending pathogens and debris, but can damage surrounding parenchyma, setting the stage for abscess formation)

13
Q

Major basic protein

A

contained in eosinophils

cationic protein that causes significant damage to parasites.

occasionally causes lysis of epithelial cells, resulting in host tissue damage.

14
Q

IFN-r production by CD4+ lymphocytes

A

responsible for phagolysosome formation, inducible nitric oxide synthase release, and development of granulomas and caseous necrosis

15
Q

Anticipation

A

Tendency for clinical symptoms to worsen and/or occur earlier in subsequent generations.

Common in disorders associated with trinucleotide repeats - Fragile X syndrome, myotonic dystrophy, and Friedrich ataxia.

16
Q

Pleiotropy

A

Mutation of one gene leads to multiple phenotypic abnormalities

17
Q

Genomic imprinting

A

selective inactivation of genes of either maternal or paternal origin, causing a phenomenon called “parent-of-origin gene expression”

Parder-Willi - deletion from the father; children show insatiable hunger and thirst and emotional lability

Angelman - deletions inherited from mother; “happy puppet” syndrome since children show jerky movements and happy predisposition.

18
Q

Treatment of diabetic ketoacidosis

A

IV hydration with normal saline and insulin.

This leads to decrease in serum glucose, osmolality, and potassium, as well as increases in serum bicarbonate and sodium.

19
Q

What causes increased insulin resistance in overweight individuals?

A

Free fatty acids and serum triglycerides

20
Q

Beta-hydroxybutyrate

A

Marker of insulin deficiency

Present in type I diabetes mellitus.

21
Q

Primary hyperparathyroidism

A

Parathyroid adenoma that causes “bones, stones, abdominal groans, and psychic moans”. Hypercalcemia:

  1. PTH mediated increase in renal tubular Ca reabsorption
  2. Increased production of calcitrol in kidneys causing increased GI Ca absorption
  3. PTH-mediated increase in bone resorption

Involves cortical (compact) bone in appendicular skeleton. Subperiosteal erosions in phalanges of hand, granular “salt and pepper” skull, and osteolytic cysts in long bones (Osteitis fibrosa cystica).

22
Q

Osteoporosis

A

Trabecular thinning with fewere interconnections.

23
Q

Osteopetrosis

A

“marble bone disease”

decreased osteoclastic bone resoprtion, which results in accumulation of woven bone and diffuse skeletal thickening

Persistence of primary spongiosa in the medullary cavity with no mature trabeculae

24
Q

Hartnup Disease

A

Can result in niacin deficiency due to excess loss of dietary tryptophan, resulting from defective intestinal and renal tubular absorption of that amino acid.

Niacin (B3) is synthesized from tryptophan and tryptophan is an essential amino acid.

Aminoacidura (containing neutral amino acids, not proline, hydroxyproline and arginine - differentiates from Fanconi syndrome)

25
Q

Tetanospasmin

A

travel by retrograde axonal transport into the CNS. binds ganglioside receptors on neuronal membranes and the light chain inhibits release of glycine and GABA from inhibitory interneurons.

leads to sustained muscle contraction:

masseter muscle spasm (lockjaw), opisthotonos, dysphagia, facial muscle spasm (Risus sardonicus)

26
Q

Rinne test

A

Compares sound heard from mastoid bone to the external auditory meatus. (Air-conducted sound usually louder and longer than bone-conducted sound).

+ (normal): if sound is heard best at external auditory meatus.

Sensorineural hearing loss would be normal.

- (abnormal): if vibration heard better at mastoid

Suggests conductive hearing loss.

27
Q

Weber test

A

Differentiates between conductive and sensorineural hearing loss and localizes affected ear.

Vibration is normally heard equally in both ears.

Conductive hearing loss causes lateralization to the affected ear, as the conduction deficit masks ambient noise.

Sensorineural hearing loss causes lateralization to the unaffected ear, as the unimpaired inner ear can better sense the vibration.

28
Q

Adverse effects of protease inhibitors

A

Lipodystrophy - deposition of fat on back and abdomen and decreased adipose on the extremities, leading to “buffalo hump” appearance with central obesity and peripheral wasting.

Hyperglycemia

Inhibition of P450 (Should not use with Rifampin which increases activity of P450 and decreases serum protease inhibitors - Rifabutin should be used instead)

29
Q

TMP-SMX Side effects

A

Megaloblastic anemia, Steven-Johnson syndrome and toxic epidermal necrolysis

30
Q

Lipoic acid

A

Coenzyme for:

alpha-ketoglutarate dehydrogenase + branched-chain ketoacid dehydrogenase (deficiency results in maple syrup urine disease)

pyruvate dehydrogenase (deficiency results in lactic acidosis)

31
Q

Pyruvate kinase deficiency

A

causes hemolytic anemia due to failure of glycolysis and resultant failure to generate sufficient ATP to maintain erythrocyte structure.

Splenic hypertrophy results from increased work of the splenic parenchyma, which must removed these deformed erythrocytes from the circulation.

32
Q

Accumulation of sphingomyelin resulting in splenomegaly

A

Niemann-Pick disease

33
Q

Accumulation of glucocerebrosides responsible for splenomegaly

A

Gaucher disease

34
Q

Vinca alkaloid (Vincristine or Vinblastine)

A

Function by inhibiting microtubule formation.

Causes cell cycle-specific cytotoxicity during hte M phase of the cell cycle as the replicated chromosomes are unable to align and segregate.

Vincristine - neurotoxicity, peripheral neuropathy (because impaired transporting organelles from neuronal cell body to axon terminals)

35
Q

Nifedipine

A

Causes peripheral vasodilation which may result in reflex tachycardia.

This antihypertensive drug is useful for patients with bradycardia.

36
Q

Tardive dyskinesia

A

Involuntary perioral movements, such as biting, chewing, grimacing, and tongue protrusions

involuntary choreoathetoid movements of the head, limbs, and trunk may also be observed.

Develops 4 months - 4 years after treatment with antipsychotics. May be irreversible.

37
Q

Atypical antipsychotics and extrapyramidal symptoms

A

Risperidone - most likely to cause EPS

Clozapine - least likely to cause EPS. but is associated with agranulocytosis, which is why it is a medication of last resort

38
Q

Acute dystonia

A

4 hours - 4 days after antipsychotic medication

Muscle spasms or stiffness, tongue protrusions or twisting, opisthotonus, and oculogyric crisis (sustained elevation of the eyes in an upward position)

Treatmetn: antihistamines or anticholinergics

39
Q

Arcarbose and Miglitol

A

Alpha-glucosidase inhibitors that decrease the activity of disaccharidases on the intestinal border.

Cause flatulence, GI bloating, abdominal pain, and rash.

40
Q

TNF-alpha

A

Produced by macrophages in response to infection, as well as by some neoplastic cells.

Can induce a wasting syndrom (cachexia - anorexia, malaise, anemia, weight loss).

Mediates paraneoplastic cachexia in humans by suppressing appetite, inhibiting lipoprotein lipase and increasing insulin resistance of peripheral tissues.

41
Q

Colchicine

A

Used for acute gouty arthritis and prophylaxis of recurrent gouty arthritis.

Inhibits leukocyte migration and phagocytosis by blocking tubulin polymerization.

Nause and diarrhea are common side effects.

42
Q

Metronidazole when combined with alcohol

A

Metronidazole can cause disulfiram-like effects when combined with alcohol (Disulfiram is an aldehyde dehydrogenase inhibitor that causes adverse effects after alcohol consumption).

Metronidazole is used to treat giardiasis, trichomonas vaginitis, and bacterial vaginosis

43
Q

Treatment of Candida vaginitis

A

Fluconazole

44
Q

Microglia

A

Move to area of ischemic infarct approximately 3-5 days after the onset of ischemia and phagocytize the fragments of neurons, myelin, and necrotic debris.

Cystic space replaces the necrosis and astrocytes form a glial scar along the periphery.

45
Q

Adenomyosis

A

Presence of endometrial glandular tissue within the myometrium.

Causes menorrhagia and dysmenorrhea

PE reveals uniformly enlarged uterus (due to uterine SM hypertrophy and hyperplasia)

46
Q

Leiomyoma

A

Common benign pseudoencapsulated tumor of monoclonal uterine smooth muscle cells.

PE reveals irregularly enlarged uterus or uterine mass.

47
Q

Endometrial adenocarcinoma

A

most common type of endometrial carcinoma

Glandular structures with malignant-appearing cells (nuclear atypia, increased mitotic activity) invade the uterine wall by direct extension.

Most common presentation: abnormal uterine bleeding in a postmenopausal woman.

48
Q

Endometriosis

A

Presence of normal endometrial tissue in abnormal locations (outside the uterus)

These ectopic foci of endometrial tissue undergo menstrual-type bleeding causing cyclic pelvic pain (dysmenorrhea) due to local inflammation and fibrosis

49
Q

Peptic ulcers with least risk of malignancy

A

Duodenal ulcers

50
Q

Syringomyelia

A

Disproportionate loss of pain and temperature sensation (dissociated anesthesia) involving the arms and hands.

Formation of a cavity (syrinx) in the cervical region of the spinal cord.

The syrinx damages the ventral white commissure, leading to bilateral loss of pain and temperature sensation that is limited to the affected levels (typically arms and hands); distal sensation is preserved.

Destruction of motor neurons in the ventral horns causes flaccid paralysis and atrophy of the intrinsic muscles of the hand.

51
Q

Non-selective beta-blockers and hypoglycemia

A

During hypoglycemia: adrenergic symptoms (sweating, tremor, palpitations) are early signs. CNS symptoms develop later.

Non-selective b-blockers can inhibit epinephrine and norepinephrine-mediated compensatory reactions to hypoglycemia. Mask its adrenergic symptoms.

Blockade of b2 receptors inhibits hepatic gluconeogenesis and peripheral glycogenolysis and lipolysis and exacerbate hypoglycemia.

Selective b1 antagonists should be used instead if a b-blocker is necessary

52
Q

Superior Vena Cava

A

Intrathoracic spread of bronchogenic carcinoma or non-Hodgkin lymphoma may lead to compression of the superior vena cava, causing impaired venous return from the upper part of the body.

Signs and symptoms include dyspnea, facial swelling, and dilated collateral veins in the upper trunk.