Infectious Diseases (6%) Flashcards
1
Q
botulism
A
- clostridium botulinum, results from ingestion of preformed toxins produced by spores
- source: improperly stored food (home canned goods), inactivated by cooking food at high temps (212F x10mins), wound contamination
- sxs: GI sxs (abd cramps, N/V/D), hallmark is symmetric descending flaccid paralysis starting with dry mouth, double vision, ptosis, and/or dysarthria, paralysis of limb musculature (late), resp distress leading to death
- dx: c. botulinum toxin in serum, stool, gastric bioassay
- tx: admit pt and observe resp status (gastric lavage only in first few hours), if high suspicion administer antitoxin, contaminated wounds = wound cleansing and PCN
2
Q
Chlamydia etiology and sxs
A
- Most common bacterial STD
- RF: lack of condom use, lower socioeconomic status, living in an urban area, having multiple sex partners
- most common in F 15-19, then 20-24
- independent risk factor for cervical cancer
- Sxs:
- men: dysuria, purulent urethral discharge, itching, scrotal pain and swelling, fever
- women: puruelnt urethral discharge, intermenstrual or post-coital bleeding, dysuria
- mucopurulent discharge from cervical os, friable cervix
3
Q
chlamydia diagnostics and tx
A
- Tx: NAAT, wet mount (leukorrhea >10 WBC), culture, enzyme immunoassay, PCR
4
Q
Gonorrhea etiology and sxs
A
- transmitted sexually or neonatally
- 30% coinfected with chlamydia
- Sxs: asymptomatic in women, symptomatic in men
- Cervicitis or urethritis (purulent discharge, dysuria, intermenstrual bleeding)
- Disseminated: fever, arthralgias, tenosynovitis, septic arthritis, endocarditis, meningitis, skin rash (distal extremities)
5
Q
Gonorrhea dx and tx
A
- dx: NAAT, gram stain (leukocytes, gram neg intracell. diplococci), cultures (men from urethra, women from endocervix)
- tx: tx empirically because cultures take 1-2d
- Ceftriaxone x1, add Azithromycin or doxy to cover chlamydia
- if disseminated, hospitalize and IV or IM ceftriaxone
- Complications of dz: PID, infertility, epididymitis, prostatitis, salpingitis, tubo-ovarian abscess, Fitz-Hugh-Curtis syndrome
6
Q
diphtheria
A
- corynebacterium diphtheria
- transmission: resp secretions; produces EXOTOXIN causing myocarditis and neuropathy
- sxs: nasal infxn/discharge, laryngeal infxn, pharyngeal infxn (tenacious gray membrane covering tonsils and pharynx, mild sore throat, fever, malaise, myocarditis, neuropathy involving cranial nerves
- dx: cx to confirm, but CLINICAL dx
- tx: horse serum antitoxin from CDC, if airway obst remove via laryngoscopy, PCN or erythromycin, diphtheria toxoid as vaccine (DTaP) or Td
7
Q
tetanus
A
- neurotoxins produced by spores of clostridium tetani, a gram pos anaerobic bacillus (proliferates producing exotoxin in contaminated wounds)
- RF: incomplete or no tetanus IMZ
- sxs: hypertonicity and contraction of masseter mm - trismus or lockjaw, progresses to severe, generalized muscle contractions, risus sardonicus = grin dt contraction of facial muscles, opisthotonos = arched back dt contraction of back mm, sympathetic hyperactivity
- dx: clinical, obtain wound cx but unreliable
- tx: admit to ICU, resp support, diazepam for tetany, neutralize unbound toxin with passive IMZ, give single IM dose of tetanus immune globulin (TIG)
8
Q
acute rheumatic fever
A
- supporting RF: previous (+) throat cx or RAT (66%), elevated or rising strep ab titer
- complications: mitral stenosis
- major criteria: polyarthritis, carditis, chorea, erythema marginatum (red patches with central clearing), subcutaneous nodules)
- minor criteria: fever (>39), arthralgia, elevated CRP or ESR, prolonged PR interval (mitral regurg)
- dx: throat cx or RAT, ASO titer establishes recent strep infxn
- dx criteria: 2 major or 1 major and 2 minor + supporting evidence
- exceptions: chorea or indolent carditis with normal anti strep ab levels
- tx: PO ASA QID for 2-4 wk, 1.2 million U benzathine PCN IM, prednisone,
- prophylaxis: benzathine PCN G
9
Q
Rocky Mountain Spotted Fever
A
- southeast, midwest, western US, spring and summer, intracellular bacteria rickettsia rickettsii
- transmission: vector-borne (dog ticks)
- sxs: onset sxs within 1 wk after bite, sudden onset F, chills, HA, photophobia, N/V, malaise, myalgias, papular rash (begins peripherally - wrists, forearms, ankles - and spreads centrally to rest of limbs, trunk, and face), becomes maculopapular - (nonblanching petechial rash
- may lead to interstitial pneumonitis, resp failure, and/or CNS involvement
- dx: elevated LFTs, thrombocytopenia, acute and convalescent serology, immunofluorescent staining of skin bx
- tx: doxy x7d, if preg or CNS manifestations tx with chloramphenicol
10
Q
Salmonella
A
- Duration: 1wk
- Transmission: food, water, fecal-oral
- Incubation: 5d-2wk (typhoid)
- sxs: inflamm D, N/V, sxs appear 24-48h after ingesting food (Salmonella typhi presents as C), possible fever
- dx: fecal leuks +, C. diff toxin and cx, 3 stool sample for ova and parasites, bact. stool cx, hypokalemia and met acidosis
- tx: cipro
11
Q
Cholera
A
- acute diarrheal dz, profound rapidly progressive dehydration and death
- protein enterotoxin produced by orgs as it colonizes
- consumption of contaminated shellfish
- Onset: 24-48h after consumption
- sxs: watery diarrhea “rice water stool” dt action of cholera toxin
- signs: fishy odor
- tx: tetracycline, FQs, or macrolide, oral rehydration
12
Q
Shigella
A
- Duration: 1wk
- Transmisison: fecal-oral, MC in developing countries, children <5
- sxs: abd pain, inflamm D, mucoid and bloody stool, N/V (less common), tenesmus (feeling like u need to constantly poop), poss fever
- dx: fecal leuks +, C diff toxin, 3 stool samps for ova and parasites, bact. stool cx, hypokalmeia and met acidosis, produces largest quantity of fecal leuks than any other gastroenteritis
- tx: TMP/SMX (bactrim)
13
Q
candidiasis
A
- 2nd MCC vaginitis
- RF: high dose OCP, diaphragm use, DM, abx, pregnant, immune suppression, tight clothes
- signs, sxs: vulvar or vag itching, burning, external dysuria, dyspareunia, odorless thick cottage cheese curd-like d/c
- erythema of vulva, excoriations from scratching
- dx: wet mount - budding yeast
- gram stain - pseudohyphae
- vaginal culture (+) for yeast
- pH <4.7 (acidic)
- tx: fluconazole 150 PO once
- tx uncircumcised partners
- short-course topical azole
- recurrent: weekly topical /PO
- resistant: boric acid TID x7d
14
Q
primary, secondary, latent, and tertiary syphilis
A
- TREPONEMA PALLIDUM
- Primary:
- chancre - painless, clean base, 3-4wk after exposure, heals in 14wk w/o light tx, HIGHLY INFXS
- inguinal lymphadenopathy
- Secondary:
- flu-like (HA, fever, sore throat, malaise)
- 4-8 wks after chancre heals, maculopapular rash
- aseptic meningitis
- 1/3 develop latent syphilis
- Latent:
- serological test in absence of clinical sxs
- 2/3 remain asymptomatic
- “early latent” = if serology + for <1 y, may relapse to secondary
- “late latent” = if serology + for >1y, patients are contagious
- Tertiary:
- years after primary infxn
- neurosyphilis, CV syphilis, gummas
- neurosyph: dementia, personality changes, tabes dorsalis (post column degen, loss of corrdination of mvmt)
- rare d/t tx with PCN
15
Q
Syphilis dx and tx
A
- Dark field microscopy (GOLD STANDARD)
- Serologic tests (MC)
- Non-treponemal tests: RPR, VDRL
- Treponemal tests: FTA-ABS, MHA-TP
- if FTA-ABS +, check for CSF-FTA-ABS
- test all pts for HIV
- Tx: PCN G (one dse IM)
- doxy and tetra x2wks if PCN allergy
- latent or tertiary: PCN x3 doses IM (1 wk apart)
- neurosyph: IV PCN x 10-14d
- repeat nontreponemal tests q3 mos
- Jarisch-Herxheimer rxn can occur w/ sudden massive destruction of spirochetes - prevent by administering antipyretics during first 24h of tx
- Report to public health agency
16
Q
cryptococcosis (PNA)
A
- MCC: cryptococcus neoformans serotype A (AIDS), cryptococcus gattii; encapsulated budding yeast found in soil contaminated with dried pigeon dung, cockroaches, or bird droppings
- transmission: inhalation, common in immunocompromised and solid organ transplant hosts, MC areas for infxn = lungs and CNS; CD4 <100 if AIDS
- sxs: hx pulm dz if COPD, steroid use, posttransplant, fever (low grade - MC in HIV), productive cough, dyspnea, HA, wt loss, pleuritic chest pain, malaise
- signs: pleural effusions, LAD
- complications: meningitis, meningoencephalitis
- dx: CXR (solitary or mult nodules, granulomas, patchy pneumonitis), india ink (confirms, CSF - variable pleocytosis mostly lymphocytes, inc opening pressure, inc protein, dec gluc), cx of BAL; cx = budding, encapsulated fungus; CSF = crypt antigen; CT or MRI
- tx: obs only if CSR nl, CSF cx or other tests (-), urine cx (-), lesion small, stable, or shrinking, no predisp conditions for dissem
- PO fluconazole, if severe = amphotericin B, +/- flucytosine
17
Q
histoplasmosis etiology, RF, and sxs
A
- fungal infxn MC associated with spelunkers, bat droppings, chicken coops - infxn of lung leading to granuloma formation
- histoplasma capsulatum (dimorph fungus with septate hyphae), Ohio and Mississippi river valleys
- RF: AIDS CD4 <150, use of steroids, hematologic malig, solid organ transplant
- sxs: 90% asxatic, flu-like sxs, F, HA, malaise, myalgia, abd pain, chills, severe SOB, worsening cough, hemoptysis, CP, jnt pain, skin lesions, wt loss, D, abd pain, periph edema, angina, confusion, szs, AMS
- signs: erythema nodosum, erythema multiforme, arthritis, HSM, hilar and mediastinal nodes, rales/wheezes, hypoxemia, pericardial rubs, abd mass, intestinal ulcers, CN deficits, meningismus, mm weakness, ataxia
18
Q
histoplasmosis dx and tx
A
- dx: urine and serum ag testing (cross reactivity with blastomyces and coccidiodes = false +), BAL ag testing, pancytopenia, AST/ALT elevated, LDH elevated, sputum cxs, blood cxs, abx (anti-H = active, anti-M = chronic), complement fixing Ab
- Imaging: CXR (hilar and mediastinal nodes (coin lesions), cavitation in upper lobes, CT look for adrenal involvement, echo TEE or TTE if valvular involvment suspected, LB
- tx: acute asxatic = no tx; acute sxatic = PO itraconazole x 3mo, amphotericin B for severe or immunocompromised host
19
Q
pneumocystis PNA
A
- pneumocystis jiroveci - caused by fungus found in lungs of mammals, MC opportunistic infxn in HIV/AIDS
- sxs: F, SOB, nonproductive cough, exam findings disproportunate to imaging, showing diffuse interstitial infiltrates, fatigue, weakness, wt loss
- dx: CXR (definitive - diffuse or perihilar infiltrates, reticular interstitial PNA or airspace dz that mimics pulm edema), sputum wright-giemsa stain or DFA, BAL, CD4 <200 if AIDS, ABG hypoxia, hypocapnia, reduced DLCO, LDH inc but nonspecific, serum B-glucan, WBC low
- tx: BACTRIM, add roids if PaO2 <70, dapsone if sulfa allergy
- all pts with CD4 <200 should undergo prophylaxis (bactrim)
20
Q
atypical mycobacterial disease
A
- etiology: mycobacterium avium complex (MAC), M. fortuitum complex, M. kansassi
- no airbonrne contact, noncontagious
- sxs: indolent or subacute course
- MC sx = fever, cough, SOB, fatigue, weight loss, hemoptysis
- unilateral cervical, submandibular, or preauricular lymphadenitis - painless and firm, no warmth and well circumscribed
- but fever and systemic sxs are minimal or absent
- dx: Runyon criteria: nonchromogens (MAC) - produce no pigment, rapid growers; produce visible growth on standard agar in 1 wk, which usually takes 2
- Ziehl-Neelsen: AFB +
- PPD: + or -
- AFB smear and cx
- tx: surgical excision - if excision is not possible or there is a recurrence of dz, antimycobacterial drugs may be used = clarithromycin, azithromycin, rifampin and rifabutin, ethambutol