7. Infectious disease Flashcards
Failure to thrive, lymphadenopathy, opportunistic infections (eg Pneumocystis pneumonia, thrush) in infancy suggests what? How do you confirm the dx?
HIV in infancy (dec CD4 T cells)
PCR reaction testing confirms dx.
Group A strep pharyngitis (Fever, tonsillar exudate,s tender anterior cervical lymphadenopathy). Next step if suspected in a child vs adult?
Always confirm with rapid strep test or throat culture bf starting abx. Penicillin and amoxicillin is preferred tx.
Note: adults who meet all Centor criteria (fever, ant cervical lymphadenopathy, tonsillar exudates, no cough) can receive abx w/o testing.
In HIV patients, when can patients receive a live attenuated vaccine and when can they not?
Can get vaccine: Immunocompetent (CD4 >200)
Cant get vaccine: immunocompromised (CD4 <200)
Fever, hypotension, diffuse red macular rash involving palms and soles in a female a few days after period started? Tx?
TSS - staph aureus exotoxin release
Tx - fluid replacement and abx
What is the most approp step in management if ventilator-assoc pneumonia is suspected?
Gram stain and culture of resp secretions
Usually VAP dev >48 after intubation
HIV positive patient with MRI showing ring-enhancing mass in periventricular area. Serology positive for toxoplasma. PCR shows EBV DNA. Dx?
Primary CNS lymphoma
Note: positive toxoplasma is common in normal subjects - not specific for toxo.
Infection with what organisms should you suspect in IV drug users presenting with pulm sx, and cavitary lesions in lungs?
Staph aureus - septic pulmonary embolism from infective endocarditis of tricuspid valve.
Fever, toxicity, pharyngitis with possible grey-white exudate, sandpaper-like rash, in child is suspicious for what?
Scarlet fever - GAS
Tx - penicillin V
Erysipelas (skin infx of the upper dermis and superficial lymphatics) is most commonly caused by what infection?
Group A strep.
Sx - fever, chills, regional lymphadenitis. Involvement of external ear is particularly suggestive of erysipelas (this skin lacks lower dermis level), making cellulitis (deeper skin infx) less likely.
Acute febrile rxn <12 h after initial tx of early syphilis. Sx include fever, HA, myalgias, rigors, sweating, hypotension, and worsening syphilitic rash. Dx?
Jarish-Herxheimer rxn due to rapid lysis of spirochetes. Self-limited
What are the 3 phases of bordetella pertussis?
- catarrhal - mild cough/rhinitis (1-2wk)
- paroxysmal - severe paroxysms of coughing and posttussive emesis (2-6wk)
- convalescent - sx resolve gradually (wk-mo)
A patient with CD4 count 30/mm3 and excruciating pain with swallowing is likely to have candida albicans or viral esophagitis?
Viral is more likely. HSV and CMV common. Dx with endoscopy with bx. Candida would have mild to moderate pain with swalling and oral thrush
How else can pregnant women acquire toxoplasmosis aside from cat feces?
ingestion of raw or undercooked meat.
Infants are asymp at birth by experience chorioretinitis in adulthood. If symptomatic at birth they may have macrocephaly, diffuse intracerebral calcifications, and hydrocephalus.
What are some extrahepatic manifestations of chronic hep C?
Derm: porphyria cutanea tarda (vesicles and bullae with trauma or sun exposure), lichen planus
Heme; mixed cryoglobulinemia syndrome (palpable purpura, arthralgias, low complement)
Glomerulonephritis
When treating pneumocystis pneumonia in an HIV pos patient, in addition to TMP-SMX, why d you add corticosteroids?
Corticosteroids have been shown to dec mortality in severe PCP. Indications for corticosteroids include PaO2 <=70 or A-a gradient >=35 on room air.
How often should the following vaccines be given in patients >=65yo?
- PCV13
- PPSV23
- Influenza vaccine
- PCV13 is rec for all adults >=65, folowed by the 23 at least 6-12mo later
- Influenza annually to all adults
Note: PPSV23 alone is recommended for adults <54 who are current smokers or have chronic medical conditions
Patients with CF are prone to pneumonia caused by what organism in the following ages?
- 0-20yo
- 20->45yo
- S aureus (more common in infants and young kids)
2. Pseudomonas aeruginosa (more common in adults)
What organism is a common cause of food-borne illness related to shellfish and wound infections related to marine environments?
Vibrio vulnificus - marine bacterium. Infx can be mild or can develop necrotizing fasciitis with hemorrhagic bullous lesions and septic shock.
Does croup present with inspiratory or expiratory stridor?
Inspiratory (barking)
Differentiate rash seen on the palm of HSV vs syphilis
HSV: herpetic whitlow; focal, unilateral, vesicular
Syphilis: secondary syphilis, symmetric, macular/papular on palms and soles.
If lyme disease is suspected from an erythema migrans rash, what is the best next step in management?
Oral doxycycline. Don’t need to do serology bc too insensitive and can be seronegative. Only perform if patient has signs of early disseminated or late disease
What are the MCC of acute, UNIilateral lymphadenitis in children (enlarged, erythematous, tender, submandibular nodules most common)?
S aureus, and Strep pyogenes
Note: Prevotella sp can cause this in the setting of poor dentition and caries
What is the MCC of meningitis/neonatal sepsis in young infants? Sx? Prophy?
Group B strep
hyper or hypothermia, resp distress, irritable, vomit, jaundice, bulging fontanelles, apnea, seizure
Prophy: maternal screening before delivery and with intrapartum abx. Note: only works for early onset GBS, not late onset (>7 days)
Why shouldn’t you give ampicillin or amoxicillin to a patient with mono?
Development of polymorphous, maculopapular rash
