Medical Knowledge Flashcards
most common agents for immediate hypersensitivity reaction?
- neuromuscular blocking agent > latex > antibiotics
max lidocaine dose? w/ or w/o epi? most common side effect of toxicity
7 mg/kg with epi, 5 mg/kg without epi, toxicity - light headedness, parasthesias, tinnitus, blurred vision; can progress to lethargy, tremors, seizures, arrest – tx w/ intralipids
goals of anesthesia in a pt w/ aortic stenosis
avoid hypotension, ensure adequate LV end diastolic volume, and maintenence of normal sinus rhythm
effects of dopamine based on dose?
low dose (1-2 mcg/kg/min) dopamineric -> renal/visceral vasodilation; medium dose (3-10 mcg/kg/min) beta1 adrenergic dominant, similar to dobutamine; large dose (>10 mcg/kg/min) alpha1 predominant, perpiheral vasoconstriction similar to phenylephrine
respiratory depression after interscalene nerve block
diaphragm paralysis (C3-C5 nerve roots close proximity to target areas of the block – C5-T1)
what anesthestic drug is contraindicated in burns
succinylcholine - causes rapid increase in intravascular K+
main side effect of barbituate toxicity
myocardial depression
cyanosis while 100% pulse ox
methemoglobinemia - treat with IV methylene blue
how to confirm ET tube placement (after ET CO2 was abnormally low in a trauma pt getting active CPR)
transtracheal ultrasound
what differentiates mallampampti class 2 and 3?
class 2 = uvula is only partially seen (as opposed to clase 1 where fully seen); class 3 only can see the soft and hard palate
describe rapid sequence intubation
preoxygenate, etomidate, succinylcholine, intubate
depolarizing muscle relaxant
succinylcholine
neuromuscular agent that undergoes hoffman degradation
cisatracurium
metabolism of rocuronium? pancuronium?
rocuronium is liver (like a Rock), pancuronium is renal (P for Pee)
hyponatremia, elevated urinary sodium, hypovolemic
cerebral salt wasting - sudden increased uop, lose volume and sodium
hyponatremia, elevated urinary sodium, euvolemia/hypervolemia
SIADH; tx w/ NS (fluid restriction could worsen cerebral ischemia in brain pts), adjuncts include demeclocycline and vaptans
physiologic changes in pregnancy
decreased pCO2, respiratory alkalosis; unchanged vital capacity, increased blood volume, dilutional anemia, right shift hemoglobin curve, increased circulating WBCs
central vs nephrogenic di
central DI = lack of ADH, nephrogenic DI = diminished renal response to DI – in central DI, administration of desmopresson will allow kidney to concentrate urine
initial management of hepatorenal syndrome
cessation of diuretics, albumin bolus – if doesnt work, may need pressors, midodrine/octreotide, liver txp
metabolic abnormalities in a pt w/ high EC fistula output from small bowel
hypokalemic, hyponatremic w/ metabolic ACIDosis (lose bicarb through small bowel)
central pontine myelinosis - caused by, how to counteract
due to rapid correction of hyponatremia (brain cells with low solutes - water goes into blood, shrinks the cells) can counteract with desmopressin/ADH because ADH helps retain water and prevent rapid autocorrection of sodium
anion gap formula
sodium - chloride - bicarb = anion gap; normal is 8-16
indication for urgent treatment of hyperkalemia
> 6.5, or ECG changes, or rhabdomyolysis
p53 effect on apoptosis
p53 Promotes apoptosis (as opposed to BCL2 - which inhibits)
spontaneous regression of malignant tumors occurs in….
melanoma, testicular germ cell tumors and neuroblastomas
cyclosporine - mechanism, adverse effects, metabolism
inhibits synthesis of IL2, IL4, nephrotoxic, gingival hyperplasia, hirsutism, thrombocytopenia; undergoes hepatic metabolism
example of type 1-4 hypersensitivity reaction; what cells mediate them
type 1 HSR - IgE / eosinophils, bee stings, allergens; type 2 HSR IgG/IgM mediated with complement activation - ABO incompatability, type 3 HSR immune complex mediated response SLE, serum sickness, RA; type 4 T cell mediated, delayed reaction, tuberculosis skin test / contact dermatitis
larget producers of TNF alpha and IL1
macrophages
IL2 is primary produced by…
T cells
IL10 functions to…
largest inhibitor of inflammatory response, macrophages
management of lung abscess
antibiotics first – should also consider bronchoscopy in pt w/ risk factors for lung ca to rule out malignancy – large abscesses or fail to respond to therapy need surgery lobectomy/pneumonectomy – perc drains considered in poor surgical candidates
mechanism of piperacillin-tazobactam
piperacillin is a beta lactam inhibitor, final step of bacteral cell wall synthesis; tazobactam binds beta lactamases
mechanism of metronidazole
inhibits nucleic acid synthesis, effective vs anaerobes
30S ribosome inhibitors
aminogyclosides, tetracycline
50S ribosome inhibitors
macrolides, linezolid, chloramphenicol
mechanism of clindamycin
lincosamide antibiotic, interferes with amino acyl-tRNA complex
what is qSOFA score
RR > 22, altered mental status, SBP <100 – if 2/3, further workup treatment of sepsis indicated
new definition of septic shock
sepsis that requires vasopressors to keep MAP >65 and lactate level greater than 2
management of perianal abscess in HIV+ pt – nuances
I&D, +/- seton, need biopsy because abscess may be presenting symptom of anal/rectal malignancy, antibiotics are routine given immunocompormised setting
soft tissue mass within a lung cavity that is surrounded by a crescent of air
aspergilloma
post exposure prophylaxis for anthrax
ciprofloxacin or doxycycline – treatment of fulminant dz is cipro/clinda/rifampin
most common organism cause of acute mesenteric lymphadenitis
yersinia enterocolitica
organism causes of toxic shock syndrome
s. aureus»_space;> s. pyogenes (group A strep)
clostridium septicum infection is associated with..
colonic and hematologic malignancies
gentamicin is effective against which organisms?
gram negative rods – specifically enterococcus and serratia – has poor activity against strep, no activity vs anaerobes, assoc w/ nephrotoxicity and CN8 toxicitiy; very low therapeutic index
prolonged use of this antibiotic is associated with peripheral neuropathy
metronidazole
first sign of tetanus
trismus
exotoxins are produced by…? endotoxins?
exotoxins are produced by gram+ organisms, endotoxins are produced by gram- organisms
respiratory quotient >1, =1.0, =0.8, =0.7
RQ is ratio of CO2 produced to O2 consumed – estimate what energy source is primary substrate for energy production – if >1, suggests lipogenesis (overfed state), if =1 carbs, 0.8 = protein, 0.7 = fats – starving patients have RQ < 0.7
protein requirement in… adult? burn pt? preterm infant?
adult = 0.8 g/kg/d, burn 2-2.5 g/kg/d, preterm 3-4 g/kg/d
gold standard of nutrition assessment in trauma pt
nitrogen balance
which patients need tapering of tpn prior to cessation
diabetics pt, poor glucose control (otherwise its unnecessary)
what does the body use after glycogen stores are depleted
breakdown of skeletal muscle and lipids – amino acids used for gluconeogenesis in liver (early), kidney (late)
what are the non-essential amino acids
alanine, aspartic acid, asparagine, glutamic acid, serine
what are the essential amino acids
phenylalanine, threonine, tryptophan, methionine, lysine, histidine – all branched chain amino acids (leucine, isoleucine, valine) are essential amino acids – conditionally essential ones are arginine, cysteine, glycine, glutamine, proline, tyrosine
most important amino acid used for gluconeogenesis by the liver? kidney?
liver: alanine, kidney: glutamine
cachexia is most associated with which type of cancer
pancreatic cancer, assoc with increased TNF alpha and PIF (proteolysis inducing factor)
chromium deficiency
diabetes, peripheral neuropathy, encephalopathy
zinc deficiency
alopecia, poor wound healing, immunosuppression, night blindness, skin stuff
copper deficiency
microcytic anemia, pancytopenia, depigmentation, osteopenia
molybdenum deficiency
toxic accumulation of sulfur containing amino acids, encephlopathy
selenium deficiency
skeletal and cardiac myopathy
nutritional basis of TPN? PPN? how to help improve hepatic steatosis with TPN
glucose for TPN, fat for PPN – carnitine supplementation for hepatic steatosis (does not reverse liver dmg)
chemotherapy approved for HCC
sorafenib
how does UV radiation cause cancer
initiator and promoter of direct DNA damage and damage of DNA repair mechanisms – UVB most significant contributor to skin dmg, more melanin is protective, mutation in ras/p53 occur early in skin cancers
how does radiation work to kill cancer
leads to increased free radicals which disrupt DNA (double strand DNA breaks), as energy increases, skin is more spared; tissue hypoxia shown to significantly reduce radiation damage (patient modifiable factor) – M phase most vulnerable stage of radiation therapy
methotrexate toxicity - dx / tx
elevated liver transaminases, reduced gfr, leukopenia, thrombocytopenia – tx w/ leucovorin (folinic acid)
most common metastasis to adrenal gland
from lung
most common metastasis from breast ca
to brain
most common metastatic tumor from melanoma
to lung (and also small bowel)
p53
chromosome 17p13.1, promotes apoptosis, tumor suppressor gene, mutation leads to unregulated cell growth (Li Fraumeni), HPV encodes protein E6 which binds/inactivates p53
most devastating complication on bevacizumab (avastin)
spontaneous bowel perforation
treatment of gastric MALT lymphomaj
eradicate H. pylori. reserve chemo/rads for pts who do not respond, have recurrence, or have mets at time of dx. however pt w/ complete GOO or uncontrollable bleeding need gastrectomy
which patients benefit from anti-EGFR monoclonal antibodies
those with K-ras wildtype gene (K-ras negative)
indication for brca testing
breast ca <50, cancer both breasts, both breast/ovarian ca in same family, male breast ca, ashkenazi Jewish descent
paralytic agent of choice for patient with underlying cirrhosis/liver dz
cisatracurium or atracurium – metabolized by Hoffman degradation (bypassing liver)
effect of bicarb in metabolic acidosis
raises pH at cost of hypernatremia, hypokalemia, and left shift of oxyhemoglobin curve (can worsen tissue hypoxia)
which medications make it so you need higher doses of warfarin?
CYP450 inducers (increases metabolism of warfarin) barbituates, phenytoin, prednisone, rifampin, omeprazole
which medications make it so you need smaller doses of warfarin?
CYP450 inhibitors (decreases metabolism of warfarin) amlodipine, cimetidine, cipro, cyclosporine, diltiazem, ketoconazole, isoniazid, propanolol
mechanism of digoxin
inhibits Na/K ATPase in myocardium, leads to increased intracellular sodium, and thus intracellular calcium, leading to stronger cardiac contraction – acts on AV node, shortens QT interval, toxicity worsened in hypokalemic pt
mechanism of 5-FU
thymidylate synthase inhibitor that inhibits purine and DNA synthesis
mechanism of cyclosporine
binds cyclophilin proteins and inhibits cytokine synthesis (IL2)
mechanism of vincristine
inhibits microtubule formation
mechanism of taxol
microtubule formation and stabilization
mechanism of infliximab
monoclonal antibody against TNF alpha - inhibits ability of TNF alpha to bind to receptors and reduce autoimmune inflammatory response
mechanism of bevacizumab
VEGF inhibitor, improve survival in pt with metastatic CRC
how to reverse warfarin – active bleeding? within 1 day? within 1 week?
PCC, oral vitamin K, autocorrection
antidote for cyanide poisoning
inhaled amyl nitrite followed by IV sodium nitrite, sodium thiosulfate converts cyanomethemoglobin to thiocyanate (metabolite that is excreted in urine)
antidote for methemoglobinemia
methylene blue
side effects: hypocalcemia, hypokalemia, gout, ototoxicity, tinnitus
furosemide
side effects: intractable nausea/emesis, particularly with EtOH
metronidazole
side effects: hyperkalemia and gynecomastia
spironolactone
side effects: fulminant hepatic failure
halothane
side effects: vasodilation resulting in cutaneous flushing
vancomycin - red man syndrome
differential diagnosis for sudden drop in end tidal CO2 in OR?
obstructed airway, accidental extubation, disconnection of the circuit, cardiac arrest, and pulmonary embolism
post op w/ pain and tenderness over angle of jaw with fevers and leukocytosis
postop parotitis - leads to decrease saliva production, tx broad spectrum antibiotics (staph coverage), warm compresses
most important predictor of colonic ischemia following AAA repair
prolonged hypotension pre-op»_space;> ligation of patent IMA
strongest predictor of pulmonary related post op complications
preop serum albumin
management of venous thrombus associated with PICC
if evidence of DVT, determine if line is still needed or not, if still needed, keep line and start anticoag for 3-6 months, if line is infected/anticoag is contraindicated, can remove line, but wait 5-7 days after initiation of heparin before removing it
most common cause of death from blood transfusion
acute lung injury > ABO incompatability > bacteral contamination
decreased fibrinogen, prolonged thrombin time, normal platelets
primary fibrinolysis (decreased platelets in DIC)
mechanism of plavix
indirectly inhibits activation of glycoprotein 2b/3a receptors on platelet surface (functionally similar to Glanzmann’s thrombocytopenia)
cryoprecipitate contains…
fibrinogen, factor 8, factor 9, vWF, fibronectin
how to prevent febrile nonhemolytic transfusion reaction
WBC filtration > washing
how to counter harmful effects of steroids/radiation on wound healing
vitamin A
describe the phases of wound healing
phase 1 - hemostasis/inflammation, neutrophils -> macrophages phase 2 - proliferation, fibroblasts 4+ days phase 3 - maturation - type 3 collagen replaced w/ type 1, angiogenesis 3-4 weeks
essential fatty acid vs zinc deficiency
delayed wound healing, increased infection, diarrhea and rash – EFA rash tend to be more scaly/ assoc. w/ dry skin; zinc primary located in perioral areas and inteartriginous skin of finger/toes
type 1 collagen deficiency
osteogenesis imperfecta
type 4 collagen deficiency
alport/goodpasture syndrome (basement membrane)
type 5 collagen deficiency
classic form of ehler’s danlos
most important layer of small bowel for tensile strength?
submucosa
most important layer of esophagus for tensile strength
mucosa (thicker squamous epithelium, vs. submucosa)
