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
