Infectious disease Flashcards
Small papules with central umbilication and central necrosis in an HIV + patient
Cutaneous cryptococcosis
Dx w/ biopsy
Treat with ampho B + flucytosine for 2 or more weeks, then oral fluconazole for a year
Pt with meningoencephalitis with mosquito bites on arms
West Nile virus
Dx: West Nile IgM in CSF
Tx: supportive
Perinatal hep B infection
Tx: immunoglobulin and vaccine within 12 hours of birth
Routine vaccine series: 0, 2 and 6 months
Serology ~3 months after 3rd vaccine dose
Active tuberculosis
Dx with sputum acid-fast bacilli smear and culture
Smear has low sensitivity
Wait for culture or nucleic acid amplification (NAA) testing for definitive results
Infectious mononucleosis
Caused by EBV
Fever, fatigue, exudative pharyngitis/tonsillitis (“white exudate”, posterior cervical lymphadenopathy
Atypical reactive lymphocytes on smear
Streptococcal pharyngitis
Caused by S. pyogenes
Sudden fever, sore throat. No URI symptoms.
Tx: amoxicillin for 10 days
Alternatives: IM penicillin if unable to tolerate oral, cephalosporin if mild penicillin allergy, azithromycin x5d if severely allergic
What does a positive antibody test to HCV mean?
Active ongoing infection
Past infection that has resolved
False positive
F/u test with HCV RNA
Chlamydia in pregnancy
Screen at first visit and 3rd trimester if risk factors present
Tx w/ azithromycin
Complications if left untreated include PPROM, preterm labor and postpartum endometritis
HIV-associated lipodystrophy
Lipoatrophy: loss of subQ fat in arms, legs, buttocks; seen with NRTIs (zidovudine)
Fat accumulation: buffalo hump, visceral abdominal fat
Also insulin resistance, dyslipidemia and incr. CV risk
Tx w/ statin
Screening test for HIV
HIV antigen (p24) and HIV-1/HIV-2 antibodies Cautious use during window period (first 4 weeks), can repeat test
What conditions should you screen for prior to initiating antiretroviral therapy?
Hep B (some antiretroviral meds have dual activities)
Hep C
TB
STDs
Syphilis testing
Screen with RPR
Confirm with FTA-ABS or VDRL
Tx of syphilis
Primary, Secondary or early latent <12mo: benzathine penicillin IM x1
Late latent >12mo or unknown duration, gummatous/CV syphilis: benzathine penicillin IM weekly x3
Neurosyphilis: aqueous penicillin G IV q4h for 2 weeks
Congenital syphilis: similar to neurosyphilis
No prevention for Jarisch-Herxheimer reaction
Dx and Tx of latent TB
Dx: positive IFB-g assay w/o symptoms or CXR findings
Tx: isoniazid for 9mo, alternative is rifampin for 4-6 months
Tx of chlamydia
Azithromycin
Tx of gonorrhea
Ceftriaxone (+azithromycin to cover chlamydia)
Persistent urethritis despite tx for chlamydia/gonorrhea
Repeat urethral swab and gram stain
Often due to infections caused by Mycoplasma genitalium or Trichomonas vaginalis
Which patients should you give oseltamivir regardless of symptom duration?
Age 65 or more
Women who are pregnant and up to 2 weeks postpartum
Underlying chronic medical illness (cardiac, pulmonary, hepatic or renal)
Immunosuppressed
Morbidly obese
Native Americans
Nursing home or care facility residents
Tx of human bites
Augmentin
Lactational mastitis
Fever, breast pain and focal inflammation
Tx with dicloxacillin or cephalexin
Post-exposure management of Hep B
Healthcare worker immune: NTD
Healthcare worker not immune and source patient:
-Positive for Hep B -> hep B immunoglobulin and vaccinate
-Negative for Hep B -> vaccinate
Tuberculous meningitis
Choroidal tubercles (yellow-white nodules near the optic disc)
Basilar meningeal enhancement on imaging
CSF with low glucose, high protein, WBC count 100-500
Dx with CSF AFB staining and culture
Tx with 4-drug therapy for 2 mo and 9-12mo of continuation therapy
Tx of acute cystitis and asymptomatic bacteriuria
Cephalexin, amoxicillin-clavulanate, fosfomycin
Cervical and preauricular adenopathy with unilateral conjunctivitis
Oculoglandular syndrome (Parinaud syndrome) due to catscratch disease Can treat with azithromycin and needle aspiration to prevent lymph node suppuration
Side effect of isoniazid
Hepatotoxicity
Ok to continue unless LFTs >5x ULN and asymptomatic or >3x ULN and symptomatic
Disseminated gonococcal infection triad
Dermatitis: 2-10 painless pustules on distal extremities
Tenosynovitis: swelling and pain with passive extension
Polyarthralgia: asymmetric small and large joints
Dx: NAAT of urinary specimen
Hand-foot-mouth disease
Caused by coxsackievirus
Sporotrichosis
Painless papule which ulcerates and drains nonpurulent, odorless fluid
Proximal lesions form along lymphatic chain
Dx: culture
Tx: 3-6mo of oral itraconazole
1st line agents for acute uncomplicated cystitis
TMP-SMX for 3 days or nitrofurantoin for 5 days
1st line for uncomplicated pyelonephritis
Ciprofloxacin
Organism responsible for concurrent otitis media and purulent conjunctivitis (otitis-conjunctivitis syndrome)
Nontypeable H. influenzae
Tx with augmentin if received amoxicillin alone in last month
Tx of infectious mono with imminent airway obstruction
IV corticosteroids
Man w/ 3 months of pelvic pain and dysuria, bacteriuria and urine leukocytes on UA
Chronic prostatitis
Tx: 6 weeks of ciprofloxacin or TMP-SMX (shorter courses result in tx failure)
Ecthyma gangrenosum
Immunosuppressed pt, central catheter
Painless red macules that rapidly develop into bullae and then quickly evolve into gangrenous ulcers with raised violaceous margins
Tx w/ anti-pseudomonal beta lactam (pip-tazo) and aminoglycoside (gentamicin)
Indications for corticosteroid use in the ICU
Alveolar-arterial oxygen gradient 35mmHg or more
Arterial oxygen tension (PaO2) <70
Dx and Tx of PJP
Dx: sputum culture or bronchoalveolar lavage
Tx: TMP-SMX +/- corticosteroids
Dx and Tx of cryptococcal meningitis
Markedly elevated opening pressures >250, low WBC count <50 with lymphocytic predominance
Positive india ink stain or cryptococcal antigen test
Tx with ampho B and flucytosine (at least 2w), then high dose fluconazole for 8 weeks then low dose for ~1 year. Can be complicated by high ICPs requiring serial lumber punctures
Antibiotics for pediatric sepsis
<28 days: ampicillin + gentamicin or cefotaxime
(caused by E. coli and GBS)
>28 days: ceftriaxone or cefotaxime + vanco if meningeal involvement suspected (S. pneumo or N. meningitidis)
TB tx in pregnancy
3-drug therapy for 2 months (no pyrazinamide), the ONH + RIF for 7 additional months Give pyridoxine (B6) supplementation
Tx sinusitis
1st line: augmentin
2nd line: doxycycline or fluoroquinolones
Management of pediatric pneumonia
Preschool/focal findings: amoxicillin for strep pneumo
School/bilateral diffuse: azithromycin for Mycoplasma
Name the source of the following oral lesions in childrem:
- Recurrent ulcers on anterior oral mucosa, no fever or systemic symptoms
- Vesicles and ulcers on posterior oropharynx
- Vesicles and ulcers on anterior oral mucosa and around mouth with fever
- Tonsillar exudate with diffuse lymphadenopathy, fever +/1 hepatosplenomegaly
- Tonsillar exudate with fever and anterioc cervical lymphadenopathy
Aphthous ulcers Herpangina (Coxsackie A virus) Herpes gingivostomatitis Infectious mononucleosis Group A strep
Pulmonary aspergillosis
- Classic triad
- Dx
- Tx
Triad: cough, pleuritic chest pain, hemoptysis
Dx: CT chest with nodule w/ ground-glass opacities and/or cavitations with air-fluid levels; galactomannan and beta-d-glucan serum levels, sputum for fungal culture
Tx: voriconazole (surgery if needed)
What is immune reconstitution inflammatory syndrome?
When someone is started on antiretroviral therapy for HIV, rapid improvement in immune function can cause a paradoxical worsening of infectious symptoms
Treat symptomatically w/ NSAIDs or with short course of steroids
Croup vs epiglottitis
Croup: barking cough, parainfluenza, steeple sign, use racemic epinephrine/IM corticosteroids
Epiglottitis: respiratory distress, drooling, high fever, H. influenzae type b (vaccine preventable), thumb sign, intubate + IV abx
Tx vaginitis
- Bacterial vaginosis
- Trichomoniasis
- Candida vaginitis
- Metronidazole or clindamycin
- Metronidazole, treat partner
- Fluconazole
Most specific and sensitive tests for osteomyelitis
Specific: probe-to-bone (91%)
Sensitive: MRI (90%)
Most common complication from diptheria
Toxin-mediated myocarditis
Tx of salmonella
Supportive
Use ciprofloxacin, Bactrim, or ceftriaxone for at risk individuals
Presentation of subphrenic abscess
2-3 weeks after abdominal surgery, swinging fever and leukocytosis. Dx w/ ultrasound
Indications for dialysis catheter removal in setting of infection
Severe sepsis
Hemodynamic instability
Evidence of metastatic infection (endocarditis)
Pus at the exit site of the catheter
Continued symptoms 72h after initiation of antibiotics
Long-term catheter (>14 days) with evidence of S. aureus, P. aeruginosa or fungi on blood cx
Headache, myalgia, arthralgia
Macular, erythematous rash and few petechiae on bilateral wrists and ankles
Rocky Mountain Spotted Fever
Labs: low platelets and sodium, increased transaminases
Dx: Rickettsia serology, skin biopsy
Tx: doxycycline
Pt with fever after travelling, after BP cuff is applied, diffuse petechiae noted on skin underneath
Hemorrhagic dengue fever, at risk for circulatory collapse
Congenital infections
Toxoplasmosis: calcification, hydrocephalus, hearing impairment, chorioretinitis
Rubella: heart defects, eye abnormalities and hearing impairment, symptomatic illness (fever, maculopapular rash) in mother
Tx of intestinal helminths
Albendazole
Tx of shingles (HSV)
Valacyclovir
Abx tx for necrotizing fasciitis
Vancomycin
Pip/tazo or carbapenem
Clindamycin
Usu. caused by group A strep
Tx for vibrio vulnificus
IV ceftriaxone and doxycycline
How to diagnose Lyme disease
Serum enzyme-linked immunosorbent assay and Western Blot
