Infectious Disease - Surgery Flashcards
What is a catheter related bloodstream infection?
Central venous catheters are the most common cause; commonly due to coag-neg staph and s. aureus, however candida is isolated in 10% of caes
RF: immunocompromise (eg post chemotherapy) or intravascular catheter (esp. in ICU)
Presentation: fever, sepsis, and/or multiorgan failure
Dx: blood cultures (or biopsy), serum beta D glucan antigen can be used as rapid indicator of possible infection
Tx: several weeks of IV antifungals
What is the association between renal transplants and CMV?
CMV establishes latent infection after initial inoculation, but infection may re-emerge in pts who are severely immunocompromised.
Pts who undergo renal transplantation are at high risk for CMV reactivation w/ viremia and/or end-organ disease.
GI tract is most common organ system affected; pts present with colitis or enteritis, including fever, malaise, vomiting, bloody diarrhea, and abdominal pain large, shallow erosions or ulcers on colonoscopy
Labs: cytopenias due to BM involvement , peripheral blood smear: atypical lymphocytes
Dx: biopsy of affected organ
Tx: antivirals (gancyclovir), reduction of immunosuppressant meds
What is a splenic abscess?
RF: infection (eg infective endocarditis) w/ hematogenous spread, hemoglobinopathy (eg sickle cell disease), immunosuppression (eg HIV), IV drug use, trauma; MVP =5x increase in risk
Presentation: classic triad - fever, leukocytosis and LUQ abdominal pain; L-sided pleuritic chest pain w/ L pleural effusion commonly seen, possible splenomegaly, most commonly due to staph, strep, and salmonella,
Dx: usually diagnosed by abdominal ct scan
Tx: combination of broad-spectrum antibiotics and splenectomy, possible percutaneous drainage in poor surgical candidates
What is entamoeba histolytica?
RF: developing nations (travel/residence), contaminated food/water, fecal-oral sexual transmission (rare)
Presentation: 90% of pt asymptomatic, colitis (diarrhea, bloody stool w/ mucus, abdominal pain), liver abscess (RUQ pain, fever) [complications = rupture to pleura/peritoneum]
Dx: stool ova and parasites, stool antigen testing (colitis), e-histolytica serology (liver abscess)
Tx: metronidazole and intraluminal antibiotic (eg paromomycin)
What is Ludwig angina?
Rapidly progressive cellulitis of the submandibular and sublingual spaces. Source of infection is most commonly an infected mandibular molar.
Usually polymicrobial w/ a mix of oral aerobic (eg viridans strep) and anaerobic bacteria
Presentation: systemic (fever, chills, malaise) and local compressive (eg mouth pain, drooling, dysphagia, muffled voice, airway compromise) manifestations; anaerobic, gas-producing bacteria may cause crepitus
Dx: CT scan of neck
Tx: IV abx (amp-sulbactam, clindamycin), removal of inciting tooth
What is necrotizing surgical infection?
Characterized by pain out of proportion to phys. exam, edema, or erythema spreading beyond the surgical site, systemic signs (fever, tachycardia, hypotension), paresthesia or anesthesia at edges of the wound, purulent, cloudy-gray discharge (“dishwater drainage”), subcutaneous gas or crepitus
More common in pt with diabetes, usually polymicrobial
Radiographic evidence of gas in deep tissues
Tx: surgical exploration and debridement
What is toxic shock syndrome?
Due to s. aureus
Fever usually >38.9C (102F)
Hypotension w/ SBP <90
Diffuse macular erythroderma
Skin desquamation, including palms and soles, 1-2 weeks after illness onset
Multisystem involvement (3 or more systems): GI (vomiting and/or diarrhea), muscular (severe myalgia or elevated creatine kinase), mucous membrane hyperemia, renal (BUN or serum creatinine >1-2x upper limit of normal), hematologic (platelets <100k), liver (ALT, AST and total bilirubin >2x upper limit of normal), CNS (altered mentation w/o focal neurologic signs)
What is echinococcus granulosus?
Epidemiology: dog tapeworm (sheep intermediate host), rural, developing countries (eg South America, Middle east); humans are incidental hosts (egg ingestion)
Presentation: initially asymptomatic (often for years), liver cyst (most common) - mass effect (RUQ pain, nausea, vomiting, hepatomegaly), rupture (fever, eosinophilia), lung cyst (cough, chest pain, hemopytsis)
Dx: U/S (large, smooth hydatid cyst often w/ daughter internal septations), IgG E. granulosus serology
Tx: albendazole, percutaneous therapy (>5cm or septations), surgery (if rupture)
What is erlichiosis?
A tick borne (amblyomma americanum) illness
Presentation: fever, myalgia, headache
Labs: leukopenia/thrombocytopenia
What is chronic granulomatous disease?
X-linked immunodeficiency resulting in abnormality of NADPH oxidase, which is responsible for “respiratory burst” (formation of superoxide radicals); surrounding phagocytes are unable to neutralize invading bacteria (fungi, catalase positive - s. aureus, serratia)
Presentation: recurrent lung + skin infections
Dx: dihydrorhodamine 123 test or nitroblue tetra(4)zolium test
Tx: no specific treatment, infection prevention w/ ppx
