Infectious Disease Flashcards
When do you see pneumocytis jiroveci pneumocytosis?
Common in AIDS when <200 CD4 cells
most common opportunistic infection in AIDS patients
Presentation of pneumocytis jiroveci?
Subacute (more indolent) fever, dyspnea, tachypnea, nonproductive cough
-interstitial infiltrates
Dx of pneumocytis jiroveci?
PCR of sputum > DFA > more sensitive than silver stain
Tx of Pneumocytis jiroveci?
TMP-SMX
-add prednisone taper over 21 days if PaO2 <70
Tx of vaginal candidiasis
-conzaole cream x 1-7 days
OR
fluconazole 100-200mg PO x 1
What happens before esophageal candidiasis?
Usually ABX, steroid & or chemo exposure
-dx via EGD w/ biopsy
Tx = IV fluconazole
Most common causes of malaria?
(these two cause >90% of US cases)
-plasmodium vivax
**falciparum is most virulent
(transmitted by female mosquitos)
Presentation of Malaria
periodic chills, fever, sweats
headache, myalgia, splenomegaly possible
(travel history is vital)
How is malaria diagnosed?
Thick/thin blood microscopy smears
Malaria prophylaxis =
Nets & Repellants PLUS
- Chloroquine or if resistance use atovaquone-proguanil
- if endemic w/ p. vivax use Primaquine
How is varicella zoster virus transmitted
Mostly by respiratory secretions
less w/ direct contact of vesicular or pustular lesions
When does varicella-zoster virus present?
When adults age, cell mediated immunity wanes, or when they are stressed!
-so if <40-50 w/ flare you should ask more questions about HIV etc
Sequelae to varicella zoster virus?
increased CVA events within 6 mo of herpes zoster
Treatment of Herpes Zoster?
mild to mod = valcyclovir or famciclovir (PO)
severe/ disseminated = acyclovir (IV)
Who should get zostavax?
Single dose for all immunocompetent people > 50-60 years old INCLUDING those w/ previous episode of zoster (but lesions must be healed)
About Zostavax (type)
Live attenuated viral vaccine
HIV should be suspected in?
Anyone who is sexually active or injects drugs is at risk for HIV infection
HIV is a retrovirus
What is Acute HIV Syndrome?
An initial manifestation of HIV.
- Mono-like illness usually more severe and needing hospitalization
- rash in 40-80% (no exposure to aminopenicillins)
- *mucocutaneous ulceration is a distinctive feature
Most common presentation of HIV?
Patient is asymptomatic and found via screening but not uncommon to find advanced disease
Routine screening for HIV =
New = enzyme immunoassay (ELISA) then viral load test Old = ELISA then confirm w/ western blot
HIV screening recommendation
Routine non-risk based opt-out HIV screening in all pts 13-64
- all pts initiating tx for TB
- all pts seeking tx for STDs
- all pregos should be screened
- Pts at high risk for HIV should be screened > or = 1 yr
Med Regimens for HIV
Regimen = 3 meds (2 NRTIs + 1NNRTI or 2NRTIS + 1 PI)
1) Nucleoside Reverse Transcriptase Inhibitors **these will always have ()
- Emtricibine (FTC)
- Tenofovir (TDF)
2) Non-nucleosdie Reverse Transciptase Inhibitors
- Efavirenz
3) Proteause Inhibitors
- fosamprenavir
- lopinavir
- atazanavir
- darunavir
Protease Inhibitor SE
Lipodystrophy and metabolic side effects
Prophylaxis when CD4 <200
for Pneumocystosis = TMP-SMX
Prophylaxis when CD4 <100
for Toxoplasmosis = TMP-SMX
Prophylaxis when CD4 <50
for Mycobacterium avium complex = Azithromycin
What causes lyme disease?
Borrelia burgdorferi spirochete
(the only two spirochetes are lyme dz and syphilis)
most common vector borne disease in US
Progression of Lyme Dz
1: (Early) constitutional symp + erythema migrans
(small red papule w/ centrifugal spread & central clearing)
2: (Disseminated)
- Cardiac symp (5% develop varying degrees of AV block)
- Neuro symp (Bell’s Palsy)
3: (Late)
- chronic arthritis may occur in up to 60% of people
(the longer the infection goes on, the harder it is to treat)
Screening tests in Lyme Dz
Antibody assay may take 4-6 weeks to turn positive after infection. Confirm w/ western blot if screen is positive or equivocal.
Tx of Lyme Dz
Doxycycline (if > 8 y/o)
Amoxicillin or cefuroxime (if < 8 y/o)
Ceftriaxone if more serious manifestations (i.e. neuro)
What causes Rocky Mountain Spotted Fever? Manifestation?
Rickettsia rickettsii
-presents as influenza prodrome and then red macular rash on 2nd-6th day of fever **1st on wrists/ankles and then spreading centrally (then turns petechial in 50%)
Tx of Rocky Mountain Spotted Fever
Treat w/ Doxycycline (EVEN KIDS)
Gonorrhea bacteria characteristics and presentation
Neisseria gonorrhoeae = gram NEG DIPLOcocci
yellow, creamy, profuse discharge (may be asymp)
Dx of gonorrhea
Nucleic acid amplification test NAAT of discharge or urine
Tx of gonorrhea
Ceftriaxone 250mg IM x 1 plus azithromycin 1g PO X1
use combo therapy even if NAAT is negative for chlamydia
Chlamydia characteristics & presentation
- most common REPORTABLE sti
- Men may be asymptomatic or urethritis or dysuria
- Women commonly asymptomatic
- **both sexes can present w/ reactive arthritis (Reiter’s)
Chylamdia Tx
Azithromycin 1g PO x 1 or Doxycyline 100mg PO BID x 7days
must retest for cure in pregnancy
Syphilis bacteria characteristics
Treponema pallidum (corkscrew shaped spirochete)
Syphilis Staging
- *great imitator**
1) Active - Primary = chancre
- Secondary = generalized MP rash on palms and soles
- Tertiary = neurosyphilis
2) Latent - Early latent if < 1 yr
- Late latent if > or = 1 yr
Early syphilis dx
Darkfield exam of lesion exudates
Later syphillis dx
1) Traditionally = RPR and confirm w/ fluorsecent treponemal antibody absorbed (FTA-ABS)
2) Reverse Seq = treponemal enzme immunoassay (EIA) if positive then do RPR w/ titer
Tx of syphilis
Benzathine Penicillin G
(if PCN allergy = ceftriaxone or doxycycline)
**treatment failures occur though, so serologic testing should be repeated 6 and 12 mo after initial treatment. Follow-up is mandatory.
Most common cause of genital ulcer in US
HSV
OTHER Common clinical manifestations of HSV
- meningoencephelitis
- esophagitis/proctitis
- *HSV-1 associated w/ Bell’s Palsy (facial muscle weakness; CN VII palsy)
Diagnosis of HSV
Tzanck smear is the historical test = intranuclear inclusions and GIANT MULTINUCLEATED CELLS
Cell culture or PCR is preferred
**PCR is test of choice for detecting HSV in spinal fluid
Low risk types primarily benign anogenital warts
6, 11
High risk types primarily anogenital cancers
16, 18
Most common non-reportable STI =
HPV
Who should get Gardasil?
Boys and girls between age of 9-26y/o
prevents 6, 11, 16, 18
Who should get cervarix?
Girls ONLY
between age 10-25
(prevents 16, 18)
Most common cause of infectious arthritis
S. aureus
(transient bacteremia > other source of infection)
Tx: antistaph abx & joint drainage
Most common cause of infectious arthritis in young sexually active people
n. gonorrhea
Tx: ceftriaxone + doxy
What bacteria do you think of in acute presentation of endocarditis
s. aureus
What bacteria do you think of in sub-acute presentation of endocarditis
strep and enterococci
Gold Standard orders in endocarditis
Blood cultures X2-3
Echo
Empiric Abx in Endocarditis
Vanco + ceftriaxone
Vanco + gentamicin
Endocarditis prophylaxis abx =
Amoxicillin 2g PO 1hr BEFORE procedure
Cephalixin 2 g PO or clindamycin PO 1hr BEFORE procedure if penicillin allergy
Bacterial Meningitis bugs in preterm to 1 mo
s. agalactiae
e. coli
Bacterial Meningitis bugs in >1mo to 50yrs
s. pneumo
n. meningitidis
h. influenzae
Bacterial Meningitis bugs in >50 y/o
s. pneumo
Aseptic Meningitis bugs
enteroviruses (coxsackie and echovirus common)
-usually in fall or summer
Bacterial Meningitis CSF
high opening pressure increased cell count 100-1000 cell differentiation = PMNs usually decreased glucose increased protein
Aseptic Meningitis CSF
normal or min elevated opening pressure
cell count 10-100s
cell differentiation = lymphs usually
glucose often normal
Empiric therapy in meningitis pts 1mo to 50y
ceftriaxone + vanco +/- ampicillin (if concern for listeria)
**listeria is a rod that is not gram negative
Add dexamethasone
Meningoencephalitis Causes
Sporadic = HSV1 > Varicella zoster virus Seasonal = est nile
West nile virus meningoencephalitis presentation
muscle weakness, flaccid paralysis “polio like virus”
Pathognomic for HSV meningoencephalitis
temporal lobe abnormalities on MRI
Tx of Meningoencephalitis
Empiric Acyclovir
Erysipelas cause, symp, tx
strep species (s. progenes)»_space; staph
rapid onset red, glistening demarcated skin
Tx: anti staph abx (cefazolin, clindamycin, vanco)
Cellulitis cause, symp, tx
step species»_space; staph
erythema less intense than erysipelas; fever, chills, erythema, induration
Furuncle cause, tx
s. aureus
Tx: warm compresses, I&D, anti-staph abx
Necrotizing fascitis cause, symp, tx
Classically = group A strep (s. pyogenes)
but most are polymicrobial
presents like cellulitis but exam findings (systemic toxicity, pain) are out of proportion
Tx: surgical emergency (extensive debridement)
Non-Inflammatory Diarrhea characteristics
- large volume, watery stool
- no blood or PMNs (mucus)
- nausea/flu-like symp are common
Differential Dx of non-inflammatory diarrhea
- viral (norovirus)
- bacterial (s. aureus, b. cereus, v. cholerae)
- protozoal (giardia, cryptospordium)
- *anti-peristaltics are usually ok**
Inflammatory Diarrehea characteristics
small volume, frequent bloody/mucus stools
abdundant PMNs
Fever, chills, abdominal pain
Differential dx for inflammatory diarrhea
e. coli, c. diff, shigella, campylobacter, salmonella
Most common cause of gastroenteritis in US
Norobirus
Food poisoning
Usually staph
N/V/D 1-6 hr later
Tx = supportive
Bacteria if food poisoning from rice
bacillus cereus
Cholera
contaminated food or H20 caused by vibrio cholera ***rice water stool*** Dx w/ stool culture Tx: lots of fluids; azithromycin or doxy decreases duration of dz
Giardia
Giardia Lamblia -most common parasitic etiology of infectious diarrhea in US -associated w/ camping/hiking *most cases asymptomatic Dx w/ stool antigen test Tx: metronidazole or tinidazole
Cryptospordiosis
fecal oral transmission
cholera-like diarrhea
Dx: stool antigen test
E. coli diarrhea
initially associated w/ undercooked hamburger, now associated w/ almost any fresh food
often afebrile
**35% of blood diarrhea
Dx: stool culture and fecal toxin testing
Tx: supportive
Complication of e.coli diarrhea
HUS
- acute renal failure
- thrombocytopenia
- hemolytic anemia
Tx of c. dif
metronidazole (if mild)
vancomycin (moderate to severe)
remember = barnyard smell
Shigellosis
presents abruptly w/ bloody diarrhea, abd pain, tenesmus, systemic toxicity
associated w/ daycare centers
Tx: fluoroquinolone for adults; azithromycin for kids
Campylobacter
gram negative s shaped rod
most common bacterial cause of infectious diarrhea
fever, watery-bloody diarrhea, and abdominal pain
Tx: Azithromycin
Complications of campylobacter infection
- Guillain Barre Syndrome
- Reactive arthritis
Salmonellosis (Gastroenteritis pattern)
-raw egg or chicken ingestion
-presents like campylobacter
Tx: fluoroquinolone
Slamonellosis (enteric fever)
any salmonella species can cause but most s. typhi is most common
Typhoid fever=
enteric fever secondary to s. typhi
-Constitutional symp, HA, GI symp (constipation or diarrhea) and generally in a *returning traveler
-dx w/ stool culture
Tx: FQ or ceftriaxone (vaccine is available)