Infectious Diseases Flashcards
factitious fever - findings
young woman pt
fever diary - unusual fever patterns (very high or brief spikes), absent diurnal variation
rapid defervescence w/o chills
which drugs can cause malignant hyperthermia?
- inhalational anesthetics - halothane, isoflurane, enflurane etc
- depolarizing mm relaxants - succinylcholine, decamethonium
pt develops sustained muscle contractions, skeletal mm rigidity, elevated CK and acute renal failure, tachycardia, hypercarbia, hypertension, hyperthermia, tachypneas and cardiac arrhythmias a few hours after general anesthesia…diagnosis?
malignant hyperthermia
what can you suspect in a pt w/ a family history of problems during anesthesia?
risk of malignant hyperthermia
MC offending agents in neuroleptic malignant syndrome
haloperidol, fluphenazine
- can occur after all D2-receptor antagonists, usually soon after starting or with dose escalation
in whom has neuroleptic malignant syndrome been reported in?
Parkinson pts who abruptly discontinue levodopa or anticholinergic therapy
compared to neuroleptic malignant syndrome, what findings are unique to serotonin syndrome?
shivering
hyperreflexia
myoclonus
ataxia
what is always next best step in septic pts with identified source of infection?
remove source of infection - indwelling catheters, drain abscess, surgical debridement
when can you use drotrecogin alfa (activated protein C)?
in severe sepsis or septic shock - APACHE score > 25 or two or more sepsis-induced organ dysfunctions (recently, shown to have no survival benefit, taken off market in 2011)
when should you consider using vasopressors in shock?
if fluid challenge fails to achieve a mean arterial pressure > 65 mmHg despite adequate fluid resuscitation (4-6L w/in 6 hours)
in pts with severe sepsis, what intervention will most likely improve survival?
aggressive fluid resuscitation w/ reduction of lactic acidosis w/in 6 hours
reasonable goals for fluid resuscitation (4)
- SCVO2 atleast 70%
- CVP of 8-12 mmHg
- MAP > 65 mmHg
- urine output atleast 0.5 ml/kg/hr
blood transfusion in shock pts?
transfusion threshold of 7g/dl is acceptable, conservative approach
for IV fluid resuscitation in shock, which is better…colloid or crystalloid solutions?
none - there is no benefit of one over the other
MC vasopressor used in septic shock
norepinephrine - potent vasocontrictor that reverses the endotoxin-induced vasodilation
role of Dopamine in shock
DA is a useful vasopressor - do not use low dose DA (no benefit on renal or other clinical outcomes)
s/e: tachycardia, arrhythmias
drotrecogin alfa (protein C) therapy should be considered in patients with the following criteria (3)
- septic shock requiring vasopressors/fluids
- sepsis-induced ARDS requiring mechanical ventilation
- any two sepsis-damaged organs
diagnostic criteria for sepsis (2)
- culture proven infection/visual ID of infection
2. evidence of systemic response to infection (fever, HR, RR, elevated WBC w/ immature band forms)
severe sepsis - definition
sepsis associated w/ organ dysfunction, hypoperfusion or hypotension
septic shock - definition
subset of severe sepsis; sepsis-induced hypotension despite adequate fluid resuscitation plus presence of perfusion abnormalities (i.e. lactic acidosis)
definition of SIRS (systemic inflammatory response syndrome)
atleast TWO of the following:
- fever > 38 or < 36
- HR > 90/min
- RR > 20/min or PCO2 < 32 mmHg
- WBC > 12000 or < 4000 or > 12% band forms
complications of untreated group A strep infection
peritonsillar abscess
poststreptococcal GN
rheumatic fever
pt presents with sore throat not improving on antibiotics, fever, dysphagia, pooling of saliva and drooling, muffled voice and deviation of uvula - probable diagnosis?
peritonsillar abscess
next best step if you suspect peritonsillar abscess?
emergency ENT consultation
treatment of peritonsillar abscess
needle drainage or surgical incision
antibiotics - ampicillin/sulbactam or parenteral penicillin G + metronidazole
can you recommend echinacea for prevention of URIs?
no - studies have failed to show consistent benefit
MCC of otitis media
strep.pneumo (followed by H.influenza and Staph aureus, Moraxella)
first line antibiotic for tx. of otitis media
amoxicillin
- oral macrolides in penicillin allergic pts
if sx of otitis media do not improve w/in 48-72 hrs of amoxicillin use, what should you do?
initiate amoxicillin-clavulanate, cefuroxime or ceftriaxone
Centor criteria for pharyngitis
estimate the probability of presence of group A strep infection
- fever
- tonsillar exudates
- tender anterior cervical LAD
- absence of cough
- 0-1 points: no testing or tx
- 2 points: rapid strep test
- 3-4 points: throat culture if neg. rapid strep test; empiric ab therapy
tx. of choice if proven group A strep pharyngitis?
penicillin
- macrolides or cephalosporins if allergic
when should you treat sinusitis with antibiotics?
pt should meet atleast 2 of the following criteria:
- sx. > 7 days
- facial pain
- purulent nasal discharge
tx. of asymptomatic bacteruria in pregnancy
ampicillin, amoxicilin or nitrofurantoin
- obtain urine culture after tx. to confirm eradication
initial tx. of acute prostatitis
IV ciprofloxacin
failure of clinical improvement of acute prostatitis within 48-72 hours warrants what further tests?
transrectal USG or contrast enhanced CT (avoid in pts w/ renal dysfunction)
tx. of asymptomatic bacteruria in non-pregnant woman
nothing recommended
gold standard for dx. pyelonephritis
presence of bacteriuria and pyuria in association w/ history and physical exam findings
standard outpatient tx. of pyelonephritis
7-14 days of oral Fluoroquinolones (i.e. ciprofloxacin) in women who are not pregnant; pregnant women - TMP/SMX
tx. of recurrent cystitis in young, otherwise healthy women
short course antibiotic self tx. - TMP/SMX for three days
prophylaxis of post-coital UTIs
ciprofloxacin
routine screening in sexually active women under age of 25 includes
chlamydia, gonorrhea and HIV (opt-out)
who should be screened for syphillis?
- all pregnant women
2. high risk pts - commercial sex workers, prisoners, any other STD, MSM, high risk behaviors
cervicitis - definition
presence of mucopurulent discharge or endocervical bleeding easily induced by gentle passage of cotton swab through cervical os
tx. of cervicitis
tx. empirically for gonorrhea and chlamydia
Ceftriaxone + doxycycline (or azithromycin)
if you are treating for diagnosed gonorrhea, what else are you ALWAYS treating for?
chlamydia (i.e. will never have ceftriaxone alone as an answer)
tx. of disseminated gonococcal infection
IV ceftriaxone
common clinical findings of disseminated gonococcal infection
septic/sterile arthritis - knees, hips, wrists
tenosynovitis
sparse peripheral necrotic pustules
diagnosis of PID
presence of abdominal discomfort, 1. uterine/adnexal tenderness or cervical motion tenderness
- temperature > 38.3
- cervical/vaginal mucopurulent discharge
- leukocytes in vaginal secretions
- documented gonorrhea/chlamydia infection
tx. of PID
ceftriaxone and doxycycline ( w/ or w/o metronidazole) for 14 days
when do you hospitalize a pt with PID? (6)
- no response to antibiotics w/in 48-72 hrs
- inability to tolerate PO antibiotics
- severe illness w/ NV or high fever
- suspected intraabdominal abscess
- pregnancy
- noncompliance w/ outpatient therapy
when do you add steroids to tx. of PCP pneumonia?
add steroids if pt has evidence of hypoxia
- PaO2 35 mmHg
tx. of PCP pneumonia
TMP-SMX for 3 weeks
- add steroids if evidence of hypoxia
prophylaxis in AIDs pt with CDC < 200
TMP-SMX for PCP pneumonia
prophylaxis in AIDs pt with CDC < 100
TMP-SMX for both PCP and toxoplasmosis
prophylaxis in AIDs pt with CDC < 50
TMP-SMX - for pcp and toxoplasmosis
azithromycin - for MAC
Dapsone - use in AIDs
- adjunctive tx. to TMP-SMX in acute PCP
2. alone as prophylactic agent for pts w/ cdc < 200 and intolerant of TMP-SMX
pt presents with recurrent Herpes Zoster (shingles) infection - what should you consider?
HIV infection (also pts on chemotherapy or who have undergone organ transplant - but this is less likely)
Tx. of recurrent herpes zoster in HIV pts
oral valacyclovir or famciclovir
- if severe or disseminated, IV acyclovir may be needed
most sensitive test for HIV infection in the acute stage
HIV viral RNA load
what two diseases should be considered in sexually active pts with rash, fever and generalized LAD?
secondary syphillis
acute retroviral syndrome
HIV positive pt presents with fever, neurological deficits and MRI showing ring-enhancing lesions; CDC < 100; dx?
toxoplasmosis
Tx. approach of suspected toxoplasmosis in HIV pt
pyrimethamine + sulfadiazine and folinic acid given for 14 days –> do follow up MRI to assess tx. response; if there is no response, consider stereotactic brain biopsy
MC form of meningitis in AIDs pts
cryptococcal meningitis (w/ CDC < 100)
dx. of cryptococcal meningitis
cryptococcal antigen in CSF or culture of organism in CSF
HIV pt presents with fever, weight loss, hepatosplenomegaly, LAD, malaise and abdominal pain; CDC < 50 - dx?
disseminated MAC
HIV pt presents with dementia, hemiparesis/paralysis of one extremity, ataxia, hemianopia and diplopia - dx?
progressive multifocal leukoencephalopathy (demyelinating disease of CNS exclusivey seen in severely immunocompromised pts)
MRI appearance of PML lesions
T2/FLAIR sequences - hyperintense areas
T1 - hypointense areas
most effective way to prevent catheter-associated UTIs
decrease catheter use - only use for specific indications and remove as soon as possible
what measure can be taken to prevent Ventilator-Associated Pneumonia?
semi-erect positioning at 45 degrees
placement of endotracheal tube in what position is superior?
oral»_space; nasal } nasal can predispose to nosocomial sinusitis
what is the “bundle” of precautions that should be taken to reduce C.difficle transmission in hospital?
barrier precautions - nonsterile gown/gloves
enhanced cleaning w/ bleach
soap and water hand washing
droplet precautions should be used for what types of infections?
illnesses transmitted by large particle i.e. Neisseria meningitidis, influenza
- pts are isolated and personnel wear face masks when within 3 feet of pt
airborne precautions to be taken when you suspect diagnosis of TB
placement of pt in a negative pressure room
use of respiratory protection by health care workers (N95 masks)
next step in someone who has a positive PPD?
chest XRay
- if XR findings are negative, tx. for latent infection with isoniazid + B6 for 9 months
initial treatment in pts with suspective or confirmed active TB
4 drug regimen: isoniazid, rifampin, ethambutol and pyrazinamide (for 2 months), then isoniazid and rifampin for another 7 months (total 9 months)
an induration of 5 mm or more after PPD is considered positive in what groups of people?
HIV, immunosuppressed pts, persons in close contact with active TB, abnormal CXR, pts on immunosuppressive agents
induration of 10 mm or more on PPD is considered positive in…
IVDA, prisoners, health care workers, pts with silicosis, DM, CRF, leukemia/lymphoma, carcinoma of head, neck or lung, recent significant weight loss, history of gastrectomy or jejunoileal bypass
what should you do before initiating treatment with a TNFa inhibitor (infliximab, etanercept, adalimumab)?
screen with PPD - if > 5 mm induration or positive interferon-gamma assay, treat for latent TB with isoniazid for 9 months; at least 2 months of isoniazid before starting infliximab
when should you suspect community-acquired MRSA pneumonia?
- pts with severe, rapidly progressive pneumonia, esp during influenza season
- pts with cavitary infiltrates on CXR
- pts with a history of MRSA infection
empiric antibiotic therapy for suspected MRSA pneumonia
cefotaxime, levofloxacin, vancomycin
pt presents with nonproductive cough, chest pain, GI symptoms (diarrhea), high fever (> 40C) and hyponatremia; pt shows signs of obtundation such as lethargy and headache- dx?
Legionnaire’s disease - legionella
how do you diagnose legionella pneumonia?
urinary antigen test
risk factors for Legionnaire’s disease
smoking diabetes mellitus hematologic malignancy and other cancers chronic kidney disease HIV infection
first line tx for community acquired pneumonia (mild)
macrolides - azithromycin or clarithromycin
tx. of lung abscess following aspiration
ampicillin-sulbactam
who should receive prophylaxis against infective endocarditis before dental procedures?
- prosthetic cardiac valves
- history of prior IE
- unrepaired cyanotic congenital heart disease
- repaired congenital heart disease for 6 months following repair
- cardiac transplantation recipients with valvulopathy
drug of choice for prophylaxis of IE
oral amoxicillin - given 30-60 minutes prior to procedure; if unable to take oral meds, given ampicillin, cefazolin or ceftriaxone IM/IV
drug of choice for prophylaxis of IE in penicillin-allergic pts
oral clindamycin, azithromycin or clarithromycin
tx. of tricuspid valve endocarditis in an IVDA
tx. for staph aureus –> vancomycin + cefipime
Tx. of penicillin-sensitive viridans strep on native valves (endocarditis)
4 weeks with either penicillin or ceftriaxone OR 2 weeks when either agent is combined with low-dose gentamicin
tx. of methicillin-susceptible staph aurea bactermia and endocarditis
synthetic penicllins, oxacillin and nafcillin
what is contact with bone using a sterile, blunt steel probe in an infected pedal ulcer is correlated with what?
underlying osteomyelitis (esp. in pt with DM)
how do you diagnose osteomyelitis of the foot in a patient with diabetes?
bone biopsy –> cultures obtained from sinus tract or ulcer base do not reflect the bacterial etiology of deep pathogens
what should you consider in any patient with new onset back pain and fever?
vertebral osteomyelitis
imaging study of choice for pts with suspected vertebral osteomyelitis
MRI
- if MRI cannot be performed (pt with pacemaker or metal prosthetic device) - do a gallium scan
when would you do a three-phase bone scintigraphy study in osteomyelitis?
when initial MRI imaging results are indeterminate
pt has MRI findings suggestive of osteomyelitis…what is the next step?
blood cultures - positive in 75% of pts (needed to guide treatment); if cultures negative, consider CT-guided percutaneous needle biopsy
