infectious disease Flashcards
causes of meningitis:
newborn 0-6 months
GBS
E coli/ gram negative rods
Listeria
causes of meningitis:
children 6 months - 6 years
S pneumoniae
N. meningitidis
H influenzae B
enterovirus
causes of meningitis:
6-60 years old
N meningitidis
enteroviruses
S pneumoniae
HSV
causes of meningitis:
60+ years
S pneumoniae
Gram negative rods
listeria
N meningitidis
causes of meningitis:
HIV patients
cryptococcus CMV HSV VZV TB toxoplasmosis (brain abscess) JC virus (PML)
meningitis
< 1 month of age
cause: GBS, E coli/ gram (-) rods, listeria
treatment _______
ampicillin + cefotaxime
or
gentamicin
meningitis
1-3 months
cause: pneumococci, meningococci, H influenzae
treatment: ______
vancomycin IV + ceftriaxone or cefotaxime
meningitis:
3 months - adulthood
cause: pneumococci, meningococci
treatment_______
vancomycin IV + ceftriaxone or cefotaxime
meningitis
> 60 years/ alcoholism/ chronic illness
pneumococci, gram (-) bacilli, listeria, meningococci
treatment: ______
ampicillin + vancomycin + cefotaxime or ceftriaxone
causes of brain abscesses
strep
staph
anaerobes
non-bacterial causes
- toxoplasma
- aspergillus
- candida
- zygomycosis if immunocompromised
can be polymicrobial
classic triad of brain abscess
headache
fever
focal neurologic deficit
note: if fever absent, primary and metastatic brain tumors should be considered in differential diagnosis
dx of brain abscess
CT: ring-enhancing lesions lab values: -peripheral leukocytosis - increased ESR -increased CRP
CSF not necessary (don’t want to cause an uncal herniation)
brain abscess treatment
initiate broad spectrum antibiotics and surgical drainage (if < 2 cm, can often do medically)
antibiotics:
- third generation cephalosporin + metronidazole +/- vancomycin (IV therapy for 6-8 weeks)
- serial CT/ MRIs
can give dexamethasone with taper to decrease cerebral edema
can give IV mannitol to decrease ICP
can give prophylactic anticonvulsants
HIV
CD4 count > 200
opportunistic infections:
bacterial infections tuberculosis herpes simplex herpes zoster vaginal candidiasis hairy leukoplakia kaposi's sarcoma
HIV
CD4 count > 50 and < 200
opportunistic infections
pneumocystosis toxoplasmosis cryptococcosis coccidioidomycosis cryptosporidiosis
HIV
CD4 count < 50
opportunistic infections
disseminated MAC infection
Histoplasmosis
CMV retinitis
CNS lymphoma
HIV-related opportunistic infection
p jiroveci pneumonia
indication for prophylaxis:
- CD4+ < 200
- prior P jiroveci infection
- unexplained fever X 2 weeks
- HIV related oral candidiasis
tx: TMP-SMX
HIV related opportunistic infection
mycobacterium avium complex (MAC)
indication for prophylaxis
-CD4+ < 50-100
tx: weekly azithromycin
HIV related opportunistic infection
toxoplasma gondii
indication for prophylaxis
-CD4+ < 100 + (+) IgG serologies
tx: double strength TMP-SMX
HIV related opportunistic infection
m tuberculosis
indication for prophylaxis
-PPD > 5 mm or “high risk”
treatment: INH x 9 months (+ pyridoxine) or rifampin X 4 months
HIV related opportunistic infection
candida
indication for prophylaxis:
-multiple reoccurences
treatment:
- esophagitis: fluconazole
- oral: nystatin swish and swallow
HIV related opportunistic infection
HSV
indication for propylaxis:
-multiple reoccurences
treatment:
-daily suppressive acyclovir, famciclovir, or valacyclovir
HIV related opportunistic infection
S pneumoniae
indication for prophylaxis
-all patients
tx: pneumovax
- give every 5 years provided that CD4+ is > 200
HIV related opportunistic infection
influenzae
indication for prophylaxis:
-all patients
treatment: influenza vaccination annually
oropharyngeal candidiasis (thrush)
- micro
- dx
- tx
KOH or gram stain
- budding yeast and/ or pseudohyphae
- germ tubes at 37C
tx:
- thrush: (nystatin suspension, clotrimazole tablets, or a PO azole such as fluconazole)
- esophagitis: (PO azole therapy)
cryptococcal meningitis
- micro
- dx
- tx
cryptococcus antigen testing
CSF india ink stain
-5-10 um yeast with capsular halo… narrow-based unequal budding
tx:
-IV amphotericin B + flucytosine X 2 weeks then flucanazole X weeks
histoplasmosis
- buzzwords
- dx
- tx
spelunking, bird/bat excrement
ohio and mississippi river valley
dx:
- urine and serum polysaccharide antigen testing
- CXR: diffuse nodular densities, focal infiltrate, cavity or hilar lymphadenopthy
tx:
- mild: support +/- itraconazole
- chronic cavitary lesions: itraconazole > 1 yr
- severe or disseminated: liposomal amphotericin B or amphotericin B X 14 days followed by itraconazole X 1 year or longer
pneumocystis jiroveci pneumonia
- micro
- dx
- tx
silver stain and immunofluorescence: comma-shaped spores
CXR: diffuse bilateral interstitial infiltrates with a ground-glass appearance
tx:
- high dose TMP-SMX X 21 days
- prednisone taper for moderate to severe hypoxemia
CMV
- dx
- tx
dx: viral isolation, culture, tissue histopathology, serum PCR
tx: ganciclovir or foscarnet
MAC
- dx
- tx
dx:
- mycobacterium blood cultures
- Labs: anemia, hypoalbuminemia, increased serum alk phos and increased LDH
- biopsy of bone marrow, intestines or liver: foamy macrophage with acid fast bacilli
tx:
-clarithromycin and consider HAART if drug naive
-second line: ethambutol +/- rifampin
continue > 12 months and until CD4+ > 100 for > 6 months
toxoplasmosis
- buzzwords
- dx
- tx
ingesting raw or undercooked meat; changing cat litter
dx:
- serology
- PCR (indicates exposure and risk of reactivation)
- CT: hypodense ring-enhancing lesions
- MRI: predilection for the basal ganglia
tx:
- high dose PO pyrimethamine + sulfadiazine and leucovorin (folic acid analog to prevent hematologic toxicity) X 4-8 weeks
- prophylaxis: TMP-SMX or pyrimethamine + dapsone when CD4 < 100 or + toxoplasmosis IgG
chlamydia
-tx
doxycycline X 7 days
or azithromycin X 1
pregnant patients: azithromycin or amoxicillin
treat sexual partners
gonorrhea
-tx
ceftriaxone IM or cefixime PO
disseminated: requires IV ceftriaxone for at least 24 hours
treat sexual partners if possible
syphilis (treponema pallidum)
- dx
- tx
dx:
- dark field microscopy
- VDRL/RPR (many false +)
- FTA-ABS
tx:
- primary and secondary: benzathine penicillin IM X 1 day…… if penicillin allergy: tetracycline or doxycycline X 14 days…… pregnant with penicillin allergy: desensitized and tx with penicillin
- latent infection: benzathine penicillin (1 dose for early latent and weekly dose for 3 weeks for late latent infection)
- neurosyphilis: penicillin IV X 10-14 days; penicillin-allergic patients should be desensitized prior to therapy
klebsiella granulomatosis
- dx
- tx
NOT painful
beefy-red ulcer with rolled edge of granulation tissue
granulomatous ulcers
dx: clinical exam and donovan bodies
tx: doxycycline or azithromycin
haemophilus ducreyi (chancroid)
- dx
- tx
painful
irregular deep well demarcated, necrotic
inguinal lymphadenopathy
dx: clinical
tx: azithomycin or ceftriaxone
HSV-1 or HSV-2
- dx
- tx
painful
malaise, myalgias, fever with vulvar burning and pruritus
dx: tzanck smear shows multinucleated giant cells; viral culture, DFA or serology
tx: acyclovir, famciclovir or valacyclovir for primary infection
HPV
- dx
- tx
NOT painful
papule (condylomata acuminata; warts)
irregular pink or white; raised; cauliflower
dx: clinical; biopsy for confirmation
tx: cryotherapy; laser or excision
- topical agents: podophyllotoxin, imiquimod, or trichloroacetic acid
common UTI bugs
serratia e coli enterobacter klebsiella pneumoniae staph saprophyticus pseudomonas proteus mirabilis
diagnosis of UTI
dx by clinical symptoms
urine dipstick / UA:
- increased leukocyte esterase
- increased nitrites (bacteria)
- increased urine pH (proteus)
- hematuria (cystitis)
microscopic
- pyuria (> 5 WBC/hpf)
- bacteriuria
urine culture: gold standard is > 10^5 CFU/mL
treatment of UTI
uncomplicated:
-PO TMP-SMX or fluoroquinolone X 3 days or nitrofurantoin X 5 days
complicated: same drugs but 7-14 days
pregnant:
-nitrofurantoin or amoxicillin X 3-7 days
urosepsis: IV antibiotics: consider broader coverage
pyelonephritis
- dx
- tx
UA and culture: similar to cystitis but with WBC CASTS
CBC: leukocytosis
imaging: if not responding to therapy in 48-72 hours: CT or MRI (look for obstruction or abscess or complication)
tx:
- mild: 7-14 days of antibiotics outpatient (fluoroquinones are first line)… encourage fluids
- serious or systemic: IV antibiotics (fluoroquinones, 3rd or 4th gen cephalosporin, b-lactam/b-lactamase inhibitors, or carbapenen)
malaria
- dx
- tx
- prophylaxis
dx
- giesma or wright-stained thick and thin blood film
- CBC: normochromic normocytic anemia with recticulocytosis
- serologic tests if available
tx:
- uncomplicated: chloroquine
- P vivax and P ovale: chloroquine + primaquine (to eradicate hyponozoites)
- severe: IV quinidine
prophylaxis:
-mefloquine (first line for chloroquine resistant malaria)
infectious mononucleosis (EBV, CMV, toxoplasmosis, HIV, HHV-6)
- diagnosis
- tx
diagnosis
- heterophil antibody (may be (-) in first few weeks)… aka mono spot test
- EBV specific antibodies can be ordered if (-) mono spot test…. if still (-) think CMV
- CBC: thrombocytopenia, lymphocytosis, >10% atypical T lymphocytes
- CMP: elevated transaminases, alk phos and total bilirubin
tx:
- support
- can use corticosteroids if airway compromise
Borrelia burgdoferi
- dx
- tx
dx:
(1) ELISA
(2) confirm with Western blot
tx:
- doxycycline
- amoxicillin if children < 8 years old or pregnant patient
- advanced disease: ceftriaxone
rickettsia rickettsii
(carried by american dog tick: Dermacentor variables)
-dx
-tx
dx:
-clinical… confirm with biopsy and indirect immunoflourescense
tx:
- doxycycline
- if pregnant: chloramphenicol
anthrax (spore-forming gram (+) bacterium Bacillus anthracis) -dx -tx -post-exposure prophylaxis
dx:
- culture isolation or
- two non culture supportive tests (PCR, immunohistochemical staining or ELISA)
-CXR for inhalational: widened mediastinum and pleural effusion
tx:
- ciprofloxacin or doxycycline PLUS 1-2 additional antibiotics for at least 14 days (for inhalation disease or cutaneous disease of face, head or neck)
- other cutaneous disease: treat 7-10 days
postexposure prophylaxis:
-ciprofloxacin (prevent inhalation anthrax… continue for 60 days)
