test #23 4.12 Flashcards
congenital lactase deficiency
rare autosomal recessive. caused by gene near (but separate from) lactase gene
bacterial fermentation of undigested lactose leads to..
fermentation, producting short-chain fatty acids and excess hydrogen —> acidic stool
stool osmotic gap
most stool osmolality –> Na and K. gap = colonic fermentation products.
when mostly electrolytes, osmotic gap low (< 50mOsm/kg).
when poorly absorbable substances present, osmotic gap large > 100mOsm/Kg
D-xylose absorption test
absorption of D-xylose diminished in numerous malabsorptive conditions. like celiac sprue. not associated w/ lactose intolerance.
D-xylose, a monosaccharide that does not require digestion for absorption; just needs an intact mucosa.
can distinguish between musocal & nonmucosal causes of malabsorption (i.e. celiac vs. pancreatic insufficiency)
lactose deficiency individuals have… (3)
increased stool osmotic gap, increased breath hydrogen content, and decreased stool pH upon lactose challenge.
pancreatic location in abdomen
head, neck, body retroperitoneal. tail is intraperitoneal.
head overlies L2. body overlies L1 and L2. posteriorly contacts aorta, superior mesenteric vessels, left kidney. tail courses w/ splenorenal ligament alongside splenic vessels
anthax most commonly acquired via
exposure to infected animals / animal products OR use as a biological weapon
not person-to-person
forms of anthrax (3)
(1) cutaneous, most common
(2) pulmonary, 5% (but nearly 100% mortality)
(3) gastrointestinal, rare
ERB-B2 gene aka.. expressed in..
Her-2/Neu.
overexpressed in breast cancer, adenocarcinoma of ovary, stomach, lung, salivary glands.
codes for transmembrane glycoprotein w/ tyrosine kinase activity.
normally expressed in small amounts.
n-myc associated with..
neuroblastoma and small cell carinoma of lung
sis proto-oncogene codes for.. overexpressed in?
platelet-derived growth factor. overexpressed in astrocytoma and osteosarcomas
rx for cryptococcus meningitis
amphotericin B + flucytosine. long-term maintenance w/ fluconazole
schizoid vs. avoidant
avoidant strongly desires acceptance. schizoid do not care.
avoidant: inadequacy, timidity, fear of rejection
diffuse esophageal spasms
periodic, non-peristaltic contractions of esophagus.
usu painful. “cork-screw” on barium esophogram.
intermittent dysphagia w/ occasional chest pain. can mimic UNSTABLE ANGINA. rule out w/ complete cardiac work-up
symptom of GERD
heartburn: burning, central pain frequently after meal or night. DES = crampy, not burn
digital rectal exam of BPH vs. prostate cancer.
BPH: rubbery.
cancer: nodular & firm
changes resulting from BPH upstream
bladder wall hypertrophies: increase contractile force.
ureter, pelvis, calyces dilate (hydronephrosis)
renal parenchyma atrophic and scarred due to reflux of urine & damage.
3rd pharyngeal puch
inferior parathyroid glands & thymus
pharyngeal pouches
1, 2, 3, 4
ears, tonsils, bottom to, top
ears, palatine tonsils, inferior parathyroid & thymus, superior parathyroid & ultimobranchial body
thyroid diverticulum from
floor of the foregut
laryngeal cartilage originates from
4th and 6th pharyngeal arches
mutation in polycythemia vera
clonal myeloproliferative disease of pluripotent hematopoietic stem cells. 95% have V617F mutation involving JAK2 gene.
replaces a valine w/ phenylalanine at 617 –> makes hematopoetic cells more sensitive to growth factors (like EPO and TPO)
EPO producing tumors
hepatocellular carcinoma, renal cell carcinoma
shigellosis can be caused by..
shigella dysenteriae, flexneri, boydii, sonnei.
80% are sonnei in US
shigella entry into body
M cells in peyer’s patches in mucosa of ileum
substrates in urea cycle
ordinarily, careless crappers are also frivolous at urination
in mito: ornithine + carbamoyl, citrulline,
in cytosol: aspartate, arginosuccinate, fumarate, arginine, urea (and regenerate ornithine)
N acetylglutamate is needed for
activity of carbamoyl synthetase II. to convert NH3 + CO2 + ATP —> carbamoyl phosphate
myasthenia gravis particularly affects
waxing & waning progressive weakness of voluntary muscles, particularly those innervated by motor nuclei of brainstem (ocular, masticatory, facial, deglutitional (swallowing), and lingual movement)
what happens when anti-nAChR binds in myasthenia gravis?
receptor internalization & complement fixation (degradation).
less opening of nicotinic cation channels –> reduced end plate potential
classic presentation of multiple sclerosis
SIIN
- scanning speech, internuclear opthalmoplegia, intention tremor, incontinence, nystagmus
eye findings w/ multiple sclerosis
optic neuritis: sudden loss of vision resulting in Marcus Gunn pupil. internuclear opthalmoplegia.
selective muscarinic antagonist for abdominal cramping, nausea, sweating, diarrhea
scopolamine and hyoscyamine
which symptoms may persist in wernicke-Korsakoff?
memory loss (korsakoff syndrome). can persist after fixing oculomotor dysfunction & ataxia in Wernicke-Korsakoff
which brain regions are damaged in korsakoff syndrome?
anterior & dorsomedial thalamic nuclei – leads to memory loss and confabulation. when unsure of fact, fill in memory gap with fabricated story they believe to be true.
presentation of wernicke-korsakoff (3)
thiamine deficiency leads to impaired neuronal energy utilization –> cell death & atrophy
- oculomotor dysfxn: damage to CN III CN VI, and vestibular nuclei. rapidly reversible w/ thiamine
- ataxia: cerebellar cortex & vestibular nuclei damage. takes longer to resolve, can be permanent
- mental status change: disorientation, apathy, decreased attn respond well. memory & learning abnormalities often persist –> korsakoff syndrome (mamillary body)
rxn catalyzed by HMG CoA reductase
HMG CoA –> mevalonate. rate limiting step in cholesterol synthesis
how do bile acid resins affect bile acid secretion (i.e. cholestyramine)
increase bile acid production and secretion 10-fold
describe amount of bile acid in body & cycles
4 grams of bile acid in body. circulated 6-8 x 1 day
how does niacin work
- inhibits adipocyte lipolysis 2. inhibits VLDL production by liver
how do fibrates work?
- activate LPL to decrease triglycerides 2. increase production of HDL my liver
tremulousness after a few days in an alcoholic?
due to alcohol withdrawal, rx: long lasting benzodiazepines [diazepam or chlordiazepoxide]
lorazepam use in patients w/ advanced liver disease (short-acting)
long term alcohol: down-regulate GABA receptors
describe alcohol withdrawal
begins 8-12 hours after last drink.
insomnia, tremulousness, mild anxiety, headache, autonomic hyperactivity (variable BP, diaphoresis, tachycardia)
if untreated: delirium tremens (generalized tonic-clonic seizures and hallucinations) may develop around day 3
rx: long lasting benzo (diazepam chlordiazepoxide)
life threatening!
baclofen
agonist of GABAb. treat spastic conditions
5 different categories of xanthomas
- eruptive xanthoma: yellow papules abruptly appear when plasma triglycerides and lipids arise
- tuberous / tendinous: latter on achilles tendons and extensor tendons of finger.
- plane xanthomas (linear lesions in skin folds strongly associated w/ primary biliary cirrhosis
- xathelasma: soft eyelid or periorbital plaques with no associated lipid abnormalities in 50% of affected individuals
histology of xanthoma
benign macrophages packed w/ finely vacuolated, “foamy” cytoplasm. contains high levels of cholesterol, phospholipids, and triglycerides. lipid-laden macrophage frequently associated w/ inflammatory cells and fibrotic stroma.
p. aeruginosa toxins
EXOTOXIN A (inactivates EF-2 via ADP ribosylation). major virulence factor
also collagenase, elastase, fibrinolysin, phospholipase C, DNAse
how does v. cholera increase cAMP?
Gs ADP ribosylation ACTIVATES adenylate cyclase.
how does b. pertussis increase cAMP?
Gi ADP ribosylation DISINHIBITS adenylate cyclase
acute serositis in SLE
fibrinous exudation. usu pleuritis and pericarditis.
common presenting features of SLE. demographic
usu women 20-40. malar facial rash, photosensitivty w/ exacerbation of cutaneous disease after sun exposure, arthralgia. constitutional symptoms: fever, malaise, weight loss. renal involvement. serositis (pleuritis, pericarditis)
3 layers of GI mucosa
epithelium, lamina propria, muscularis mucosa
erosion vs. ulcer
erosion is just mucosa (can’t penetrate through muscularis mucosae). ulcer penetrates & extend into submucosal & muscularis propria
causes of acute erosive gastropathy? symptoms?
NSAID, surgical stress, head trauma (cushing ulcer) , burns (curling ulcer) smoking, alcohol.
range of symptoms: asymptomatic, life threatening upper GI bleed (melena). epigastric discomfort, pain, nausea, vomitting.
symptoms withdrawl when remove offending agent
1st most common cause of gastric ulcer? 2nd?
1st: h. pylori
2nd: NSAID (inhibit prostaglandin synthesis, reduced mucin and bicarb secretion & gastric perfusion, increase gastric acid secretion)
two roles of leptin on appetite and metabolism
released by adipocytes
- decrease neuropeptide Y (NPY) production in arcuate nucleus of hypothalamus —> DECREASED APPETITE
- increase POMC production –> more a-MSH —> INHIBIT FOOD INTAKE
incidence
number of new cases per year / total population AT RISK
(not people w/ disease already or dead
rx for warfarin toxicity (bleeding)
fresh frozen plasma first, then vitamin K (will take time to make new clotting factors)
rx for tPA overdose
aminocapropic acid and tranexamic acid (inhibit plasminogen activation)
antiphagocytic capsule is primary virulence factor for which 3 species?
step pneumo, h. flu, and neisseria
major virulence factor for staph aureus
protein A (bind to Fc portion of IgG)
filgrastim
granulocyte colony stimulating factor analogue
neurofibromatosis I
chromosome 17: von Recklinghausen’s disease
neurofibromas are composed of..
schwann cells
troponins are situated. what does each subunit do?
small globular proteins situated alongside tropomyosin molecules. troponin composed of 3 subunits. troponin T, I and C.
troponin T: binds other troponins to tropomyosin
troponin I: binds complex to actin
troponin C: binds to calcium
what can cause drug-induced parkinsonism
D2 blockers (1st generation antipsychotics > 2nd) in the nigrostriatal pathway.
rx: antimuscarinics (trihyxyphenidyl or benztropine)
not dopa –> ppt psychosis
Kerley B lines
short horizontal lines situated perpendicular to the pleural surface that represent edema in interlobular septa
chest x-ray in acute left ventricular failure w/ pulmonary edema
cardiomegaly (heart > 1 hemithorax in size, pleural effusion (blunting of costophrenic angle), Kerley B lines, increased vascular shadowing (alveolar edema) bilaterally)
myelobasts go on to be
one of the granulocytes
chromosome 16 inversion associated with
M4Eo subtype of AML
bacterial vaginosis (gardernella) vs. trichomonas infection
trichomonas: vaginitis. yellow-green, foamy, foul smelling discharge. see motile trophozites with flagellae on wet mount microscopy
gardernella: non-painful. gray discharge w/ “fishy” odor. addition of KOH makes odor prominent: “positive whiff test”. presence of clue cells (epithelial cells w/ bacteria on them) is characteristic
fanconi anemia
autosomal recessive, hypersensitivity to DNA cross-linking agents
bloom syndrome
autosomal recessive, hypersensitivity to UV damage and chemo
bulimia
recurrent binge eating w/ compensatory behaviors to prevent weight gain (either restrictive or purging). at least 2x/wk for 3 months.
body dysmorphic disorder
intense preoccupation w/ an imagined bodily defect that leads to functional impairment (i.e. overweight despite normal BMI)
binge-purge anorexia nervosa vs. bulimia
anorexia nervosa –> abnormally low body weight ( <17.5) and amenorrhea
factitious disorder vs. malingering
factitious disorder: intentional production or feigning of physical / psychological symptoms for purpose of assuming sick role.
malingering: voluntary fabrication of symptoms for purpose of obtaining an external reward.
what cells do renal clear cell carcinoma originate from
proximal convoluted cells
hemosiderin
iron-storage complex. see in bleeds or in hemochromatosis
how does gamma-carboxylation permit coagulation factors to functoin
creates calcium-binding sites on 2,7, 9, 10; allows for intxn w/ phospholipid
which 4 populations are susceptible to vitamin K deficiency?
(1) malabsorption syndromes
(2) broad-spectrum antibiotics
(3) neonates (limited hepatic reserve, unestabilished intestinal flora, limited bioavailability of vit K in breast milk
(4) those affected w/ generalized liver disease (healthy liver’s recycle vitamin K such that little is required in diet)`
five symptoms of zinc deficiency
(1) delayed wound healing (2) alopecia (3) diarrhea (4) acrodermatitis eneteropathica (5) dysgeusia and anosmia
b2 (riboflavin) deficiency
FAD and FMN, redox rxn (succinate dehydrogenase)
cheilosis and corneal vascularization
B6 (pyridoxine) deficiency
(1) transamination (2) decarboxylation (3) glycogen phosphorylase
needed to synthesis: cystathionine, heme, niacin, histamine, neurotransmitters: 5-HT, epinephrine, norepinephrine, dopamine, GABA.
peripheral neuropathy, sideroblastic anemia (due to impaired hemoglobin synthesis and iron excess)
Zolpidem, Zalepon, esZopiclone
nonbenzo hypnotics, acts at BZI site on GABAa, reversed by flumenazil
short-acting benzo (3)
triazolam, oxazepam, midazolam
medium duration benzo (2)
temazepam and estazolam
cavernous hemangioma
birth or later. soft blue compressible mass (few cm). light microscopy –> large dilated vascular spaces.
conditions associated w/ avascular necrosis of femoral head
sickle cell, SLE, steroids & alcohol.
MRI most sensitive to diagnose
