Infectious Disease Flashcards

Question

pertussis dx and tx

Answer 1

* dx: most accurate during catarrhal phse, dx mostly clinical (cough \>2wk required), microbiological testing required to ocnfirm; **culture and PCR assays** if cough for 2-4wk, **cx = GOLD STANDARD**, must use dacron or calcium alginate swab to obtain from posterior nasopharynx; serology = alternative to cx for cough after 4+wk, WBC count = elevated, lymphocytosis * tx: abx during catarrhal phase (dec severity and duration of cough, indicated for cough \<3wk or 6wk for preg women, health care workers, or child care workers) * **macrolides (azithro, clarithro, erythro)** * macrolide intolerant (**bactrim DS,** ampicillin) * prophylaxis: single Tdap booster for adults 16-64y, postexposure prophylaxis for close contacts * complications: infxn (PNA, otitis media)

Answer 2

* infants \<1mo: azithro x5d, erythro (both are associated with inc risk hypertrophic pyloric stenosis) * infants and children \>1mo: azithro x5d, clarithro x7d * children \>2mo: macrolides, bactrim

Answer 3

* immunosuppressed pts with AIDS, solid organ transplants, leukemia, and lymphoma * MC pathogens: **candida albicans,** herpes simplex, CMV * sxs: 1 or more (odynophagia, dysphagia, **oral thrush,** retrosternal or epigastric pain, N/V) * signs: normal oral mucosa * dx: endoscopy with bx and brushings * tx: empiric - fluconazole, ganciclovir (CMV), HAART (AIDS), sxatic tx for herpes

Answer 4

* RF: HIV, dentures, DM, exposure to broad spectrum abx, or inhaled steroids * sxs: **sore** and painful, dry **mouth**, burning mouth or tongue, dysphagia, unpleasant taste * signs: thick, whitish patches on oral mucosa (easily rubbed off), diffuse erythema * dx: KOH prep (pseudohyphae or hyphae) * tx: **clotrimazole troches** (topical), nystatin, PO fluconazole

Answer 5

* 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

Answer 6

* 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

Answer 7

* 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

Answer 8

* 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)

Answer 9

* 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

Answer 10

* **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

Answer 11

* 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)**

Answer 12

* organism: toxoplasma gondii (obligate intracellular) * active infxn in immunocomp hosts are dt the release of encysted parasites that undergo rapid transformation into tachyzoites within CNS and are not contained by the immune system * definitive host: **cat (feces) -** infects birds, rodents, grazing animals (lamb, pork), humans * transmission: oral (ingestion of **contaminated soil, food, water),** by blood or organs, transplacental, lamb, beef, pork, cat litter box * MC space occupying lesion in HIV-infected pts * sxs: **cervical LAD (MC -** nontender, discrete, firm), **HA,** malaise, fatigure, fever, myalgia, sore throat, abd pain, maculopap rash, **meningoencephalitis,** confusion, **encephalitis (AMS, F, szs, HA, focal neuro findings**, motor def, CN palsies, mvmt disorders, dysmetria, visual-field loss, and aphasia * complications: PNA, myocarditis, encheph, pericarditis, polymyositis

Answer 13

* clinical dx in AIDS pt, serum IgG and **IgM** (acute) abs to toxoplasma (IgG detected 2-3wks, IgG levels precede encephalopathy), double dose contrast CT head (multiple peripheral **ring-enhancing lesions** usually in basal ganglia), MRI w/ contrast, brain bx to ro primary CNS lymphoma, labs * **CD4 \<100** if AIDS, lymphocytosis, ESR high, AST/ALT high, CSF elevated ICP, mononuc pleuocytosis, inc protein and gamma globulin level * tx: recheck serum IgM in 3wk, enceph treat = **pyrimethamine AND sulfadiazine** OR clinda, spiramycin * **bactrim DS** daily is PROPHYLAXIS

Answer 14

* 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

Answer 15

* **human herpesvirus type 5,** dsDNA virus, HIV or posttransplant, CD4 \<50, asxatic - latent - reactivates * RF: daycare, blood transfusions, mult sex partners, CMV mismatched organs or BMT * transmission: person-person, placenta, blood trans, organ trans, breast milk, sex * sxs: most asxatic, flu-like, F, malaise, myalgias, arthralgias (appears like mono) * signs: fine crackles, LAD, +/- pharyngitis, HSM * complications: esophageal ulcers (CD4 \<100), encephalitis (AMS), peripheral polyradiculopathy, retinitis (CD4 \<50) * dx: ag test (CMV pp65 in WBCs), qualitative PCR in blood and tissue, labs (lymphocytosis or leukopenia, LFTs elevated) * cx: difficult, antigens in blood, urine, CSF via PCR * **BAL** positive for CMV, tissue bx (owl's eyes, **intracytoplasmic inclusions)**, CXR consistent with pneumonia * tx: healthy without sxs = no tx; immunocompromised = CMV immunoglobulin and IV **ganciclovir** * AE = fever, rash, D, heme effects * prophylaxis: bactrim if CD4 \<50

Answer 16

* devastating, deadly viral encephalitis, contracted from a bit or scratch by infected animal; infxn from corneal transplant as well; more prominent in developing countries where rabies vaccination is not widespread * sxs: once sxs present can be fatal - pain at site of bite, **prodromal sxs** of sore throat, fatigue, HA, N/V, **encephalitis** (confusion, combativeness, hyperactivity, fever, seizures), **hydrophobia**, **ascending paralysis** * dx: virus or viral ag form infxed tissue or saliva, 4x inc in serum ab titers, **negri bodies**, PCR detection of viral RNA * tx: clean wound thoroughly, wild animal bits - send animal for immunofluorescence of brain tissue; if healthy animal - capture, place in observation x10d * known rabies: **passive IMZ** (human rabies IG 40units into wound and gluteal region), **active IMZ** (human diploid cell rabies (HDCV) vaccine in 3 IM doses into deltoid or thigh over 28d

Answer 17

* age \>50yo, caused by reactivation of variceclla-zoster virus, which is dormant in the dorsal root ganglia and reactivated during stress, infxn, or illness; occurs only in pts who have had chickenpox, contagious when open vesicles present and immunocompromised * sxs: **severe pain and rash** in dermatomal distrib (pain before rash - **thorax MC** and trigeminal distrib), vesicles = pustular on d3-4, crust over by 7-10d * signs: grouped vesicles on erythematous base * complications: **postherpetic neuralgia,** excruciating pain persisting after lesions have cleared and does not respond to analgesics, uveitis, meningoencephalitis, deafness * dx: tzanch smear, **cx of vesicular fluid**, varivax indicated for indiv \>1yo, zostavax for prevention of zoster in pts who have no CIs * tx: keep lesions dry/clean, **analgesics for pain**, local triam in lidocaine, **antivirals** (acyc, famcic, valavyc reduce incidence of PHN, reduce pain, dec length of illness), roids to dec incidenc of PHN, **live vaccine** (varizig) to reduce severity and duration

Infectious Disease Flashcards

(41 cards)