Infectious Disease Flashcards
Candidiasis
MC: vulvovaginal
- other: balanitis, mucocutaneous, mastitis, esophagitis, oropharyngeal
- RF: denture wearers, immunocompromised, children
Sxs: itching, discharge
- dyspareunia, dysuria, vaginal irritation
- vulvar erythema, swelling, and vaginal erythema
- white, curd-like but may be watery
Dx:
- wet prep: budding yeast, hyphae, pseudohyphae; no WBCs
- pH < 4.5
Mgmt:
- Azoles
Chlamydia
Intracellular bacteria
MC reportable, bacterial STI
Dangerous in women: 40% w/untreated disease will develop PID/infertility/ectopic preg
Sxs:
- asx (F 80%, M 50%)
- common cause of NGU, dysuria in men; urethritis in women
- discharge*
- diffuse pelvic pain, dyspareunia
- post-coital bleeding, friable cervix, red, inflamed, mucopurulent
- dysuria
- may have mild pelvic pain on exam
Dx:
- wet mount w/>10 WBC/hpf
- +LE on UA w/neg nitrates
- NAAT for G/C**
- routine annual screening for women < 25
Mgmt:
- Azithro 1g x1 OR doxy 100mg BID x7d OR levofloxacin 500mg qd x7d
- abstain from sex x7d
- test for cure/reinfection 3 mo later
- treat all partners in past 3 mo
Cholera general
Inflammatory type diarrhea*
- GNB (costal waters)
- ingestion of bacteria colonizes SI and produces toxin modulating CFTR
- increased secretion, loss of Na/H20 into SI
Requires large infecting dose
RF: raw/undercooked shellfish (oysters*)
- poor sanitation
- contaminated H2O
- natural disasters
Sxs:
- endemic: asx, mild “non-inflammatory” diarrhea
- epidemic: severe, dehydrating, life-threatening inflammatory diarrhea (electrolyte abnormality, hypovolemic shock)
- vomiting early, painless diarrhea w/out tenesmus (rice water stool*)
- severe cholera gravis: lose 1L+/hr, can die w/in 12hr from SCD d/t electrolyte abnormality
Cholera dx/tx
Dx:
- dark-field microscopy* = comma-shaped darting bacteria*
- green –> yellow +
- stool culture
Mgmt:
- early, aggressive fluid replacement
- IV cholera saline (Dhaka solution) - more K and bicarb
- start ORS concurrent to IV or w/in 3-4hr of stabilization
- Doxy (adults), azithro (peds)
- supplemental zinc
Diphtheria
Et: corynebacterium diphtheria; respiratory droplet spread
Sxs:
- early: ST, mild, fever, hoarseness, malaise
- obstructive membrane* forms in nasopharynx or laryngotracheal area restricting breathing/swallowing*
- “bullneck”
Complication:
- inflammation of heart (arrhythmia)
- nerves (paralysis)
Dx: swab/culture throat
Mgmt:
- tx based on clinical presentation
- antitoxin w/in 48hr
- PCN G IM/IV or Erythromycin x 10d
- isolation, DTap/Tdap
- tx close contacts
Gonococcal infections
Neisseria gonorrhea (GN diplococci)
- short incubation 2-14d
- causes active PID
Disseminated disease:
- skin (erythematous, purple nodules)
- pharynx
- eyes
- liver
- joints
Sxs: more than chlamydia, but may be asx
- heavy mucopurulent d/c
- post-coital bleeding, pelvic pain, dysuria (mc men)
- Bartholin gland cyst: infected, accumulates pus
Dx:
- wet mount w/>10 WBC/hpf
- +LE on UA w/neg nitrates
- NAAT for G/C**
- routine annual screening for women < 25
Mgmt:
- ceftriaxone 125mg IM x1 AND Azithro 1g PO
Helminth infestation
Ingesting eggs
child itches butt at night
use tape to check for worms and view them at night
Tx: albendazole 400mg PO x1, repeat in 2wk
Toxoplasmosis
Parasite spread through eating oocytes and contact with cat feces
Sxs:
- mostly asx
- HIV: organ failure, encephalitis, chorioretinitis
- blurry vision, slurred speech, HA, unsteady gait, confusion
Dx: + serology
Mgmt:
- sulfadiazine and pyrimethamine
- must give prophylaxis to HIV pt (Bactrim)
Lyme disease
Et: borrelia burgdorferi (transmitted by ixodes scapularis)
Sxs:
- constitutional
- erythema migrans (bullseye)
untreated:
- neuroborreliosis triad: lymphocytic meningitis, CN palsies, radiculoneuritis
- cardiac: AV block, pericarditis, palpitations
persistent:
- chronic arthritis
- shooting pain/numbness, tingling
Dx:
- screening EIA assay
- confirm with WB if +
- CSF studies, lyme pcr
Mgmt: Doxy
- <8y or pregnant: amoxicillin
RMSF general
MC rickettsial disease in the U.S.
Et: rickettsia rickettsii
- obligate intracellular gram neg coccobacilli
- transmission: american dog tick (Dermacentor variabilis)
- April-Sept
Location:
- SE atlantic coast
- midwest
Pathogenesis:
- organism in tick are dormant (need 1-2d of attachment)
- activated by warm blood meal
- released into saliva of tick
- prolonged exposure for transmission (24-48hr)
- spreads through lymphatic system to cause vasculitis affecting all organs
Manifestations:
- MC affects skin, adrenals
- 7d incubation
- presents w/fever, chills, HA, malaise
- rash (95%) w/in 1st week: initial, blanching 1-4mm macular lesions (petechial)
- extremities to trunk
- the larger the blood vessels the high mortality rate
- may occur on palms/soles*
RMSF dx/tx
Dx:
- CBC, LFTs: leukopenia, thrombocytopenia, inc transaminases
- serology: IgM/IgG confirmation
- generally not positive for 7-10d
- skin biopsy if + rash
Complications:
- life-threatening complications arise from widespread vasculitis; usually in pt w/out rash d/t delayed dx/tx
- encephalitis
- noncardiogenic pulmonary edema, ARDS
- cardiac arrhythmias
- coagulopathies
- GI bleeding
- Skin necrosis
Mgmt: Doxycycline 100mg PO bid x 7-10d (even kids, preg)
CMV infection
Congenital acquired: blood disorders, deafness, microcephaly, fetal death
- asx in mothers typically
IgG/IgM specific ab for CMV if pt is exposed or if there are fetal growth complications
Mgmt:
- no tx or immunization available
Prophylaxis:
- pregnant women should avoid contact w/urine or saliva of young children
- hand hygiene after handling secretions from children
EBV infections
Sxs:
- malaise, HA, low grade fever to high grade
- progress to tonsillitis +/- pharyngitis
- posterior cervical LAD = mono
- white exudates, severe fatigue FIRST
- palatal petechiae, periorbital/palpebral edema, maculopapular or morbilliform rashes
- splenomegaly
Dx: monospot finger prick (may take 1-2wk to be positive)
- blood test: peripheral blood lymphocytes + positive heterophile ab test
Mgmt:
- sx tx: rest, APAP, Ibu
- fluids
- stay out of contact sports x 6-8wk
HPV infections
- Genital: condylomata acuminate
- Cervical CA
Sxs: mostly asx, subclinical or unrecognized
Dx: clinical
- confirmed w/bx if needed
Mgmt:
- podophyllin resin
- tri/bichloracetic acid
- cryotherapy
- surgical excision
Syphilis background
Et: treponema pallidum
- corkscrew spirochete
- doubles q 24hr
Sexual transmission only when mucocutaneous syphilitic lesions are present
- MC: MSM (HIV)
Pt: 20-40yo
- MC AA
Occurs in overlapping stages classified according to symptoms and time since initial infection
Tx:
- depends on infection stage, CNS involvement
- serologic testing should be repeated 6 and 12 months after initial tx (f/u mandatory)
Reportable infection
Primary active infection (syphilis)
Localized infection representing recent infection
Sxs:
- ** Chancre ***
- firm, round, small, painless, may be asx
- well circumscribed, may look like punch biopsy
Appears at spot where T. pallidum enters body w/resultant dermatologic response
More common in genital location
Lasts 3-6wk before healing on its own
Secondary active infection (syphilis)
Systemic or disseminated infection
Wks-few months (2-6mo)
Pt w/untreated infection may develop systemic illness
+/- preceding chancre (chancre often asx)
Derm:
- Generalized rash
* MC manifestation of secondary syphilis
- rusty/brown colored, consider w/any widespread rash
- palms/soles commonly involved**
- mucosal lesion, alopecia possible
Faint, erythematous macules over upper torso/flanks -> lesions infiltrated and darker, often w/scale, darker the pt skin -> palms, soles
- Condyloma lata
- large, raised, gray/white lesions, involving warm, moist areas such as mucous membranes in mouth and perineum
- lesions occur most often in areas close to primary chancre
- highly infectious
Other:
* LAD - epitrochlear nodes
Primary / Secondary syphilis active infection TX
** Benzathine Penicillin G 2.4 mu X1
Ceftriaxone (if MP rash) or doxycycline (if allergy)
PCN Tx of syphilis may induce Jarisch-Herxheimer Rxn
- acute onset fever, rash, myalgia, HA, hypotension
- T. pallidum lacks endotoxin - rxn results from release of large amounts of treponemal lipoprotein that stimulate production of inflammatory mediators
Tertiary syphilis infection
Progression of systemic or disseminated infection - refer
Months-Years later - progressed from secondary syphilis or late latent syphilis
- can occur any time after initial infection
- Infiltrative tumors (gummas)
- small, rubbery granulomas w/necrotic center and inflamed, fibrous capsule
- may be hard to discriminate from secondary syphilis - CV involvement (Aortitis)
- chronic infiltration of aortic wall causing clotting
- wall starts to separate d/t inflammation - Neurosyphilis: may occur any stage of infection
- eye, ear, brain, spinal cord
Early (more common)
- CN dysfunction, chronic meningitis, CVA, acute AMS, auditory or ophthalmic abnormalities*
Late
- 10-30y after infection - emotional lability, memory deficit, psychosis (dementia in younger pt*)
- sensory ataxia of LE
Latent infection
“no symptoms syphilis”
- untreated and became latent
- may be diagnosed in asx pt by serologic testing
- Early latent syphilis
- <1yr w/out sxs of primary or secondary - Late latent syphilis
- >1yr w/out sxs may progress to tertiary
Mgmt:
- early: same as primary and secondary (PCN)
- late: benzathine PCN G x 3
Congenital syphilis
infected pregnant woman to fetus
- fetal infection can occur during any trimester of pregnancy
- routinely test in first tri
2/3 infants are asx at birth
transmission can occur during any stage of syphilis
Early lesions (children <4y) more common
- fever, rash, HSM
- neurosyphilis: bulging fontanelle, seizures, CN palsies
Late lesions (children >4y)
- interstitial keratitis (looks like cataract)
- bone, teeth involvement
Syphilis diagnosis
- sexual exposure history
- clinical sxs
- diagnostic tests
- direct methods (minimal use in routine practice)
- indirect methods (serologies mc)
Definitive diagnosis
- both nontrep and trep tests are reactive
H/o treat syphilis
- newly acquired syphilis infection is dx if quant testing on an RPR test reveals >4x increase in titer w/in 6mo**
- serofast - retain a low titer (<1:8) reactive nontrep tests despite successful tx
- reactive trep test in a person with h/o treated syphilis should not be used alone to dx newly acquired syphilis
Syphilis direct methods dx
evidence of inflammation that seems consistent w/syphilis
Early syphilis
- darkfield microscopy: visualization of spirochete from moist lesion (e.g. chancre)
- most don’t have access to darkfield microscopy
Nontreponemal serologic tests
Screening test
- VDRL
- RPR
- positive nontrep tests reported as titer of antibody (e.g. 1:32 - represents detection of antibody in serum diluted 32-fold)
- higher the titer, the more disease activity
False (+): pregnancy
False (-): early syphilis (presence of chancre before ab generation)
RPR - quant test and ab titers monitored to assess tx response
Specific treponemal serologic tests
Confirmatory - qualitative only, reported as reactive or nonreactive
- TP-PA
- TP-EIA - new choice and better s/s than RPR
Detect abs (IgM, IgG) to specific antigenic components of T. pallidum - appear earlier than nontrep abs
Most patients who have reactive trep tests will have reactive tests for remainder of their lives, regardless of treatment or disease activity
Dx CNS syphilis
May occur at any stage
CSF exam if:
- clinical evidence of neuro involvement observed
- setting of symptomatic late syphilis
- treatment failure (RPR not improving by 6mo) - may be in CNS now
Lumbar puncture: send for CSF VDRL
Syphilis serofast state
- rates depend on syphilis stage, pretreatment titer, point at which response is assessed
Nontrep abs decline (often adequately) after tx but fail to completely revert to NONREACTIVE: 20-40% of pts
May represent 1 of 3 situations:
- persistent low-grade infection
- variable host ab response to infection
- tissue injury due to nonsyphilitic inflammatory condition
