IDS Flashcards
Etiology of bact men
First 2 months of life (and some into month 3)
represent maternal vaginal flora—
group B Streptococcus, E.coli, Listeria
Etiology of bact men
Age 2 months to 12 years—
S. pneumoniae (peaks in first 2 years), N. meningitidis
MC spread of BM
Most from hematogenous spread, initially from bacterial colonization of nasopharynx,
and a prior or current viral infection may enhance pathogenicity
Prevention of BM
Chemoprophylaxis with______for N. meningitidis and HiB, but not for
S. pneumoniae
rifampin
- Initially may mimic a viral disease (nonspecific)
* Any organ can be affected by vasculitis and thromboembolic disease
Acute Meningococcemia
Characteristic mengingococcal rash
Characteristic meningococcal rash (black central arch and surrounding ring or erythema)
often seen before more serious signs develop
Tx of meningo
• Need high dose IV penicillin ASAP
Viral men
______ most common presentation is cerebellar ataxia and acute encephalitis
Varicella zoster:
_____ mumps: mild but with 8th-nerve damage
Epstein-Barr virus (EBV),
Viruses causing exanthems
Exanthems, especially echovirus and coxsackie, varicella, measles, and rubella
Best test for Viral Men
– PCR of CSF is the best test.
Cause—Bordetella pertussis
− Coughing adolescents and adults are major reservoirs
PERTUSSIS
Stages of pertussis
—coldlike symptoms (rhinorrhea, conjunctival injection, cough
Catarrhal phase (2 weeks)
Stages of pertussis
__________—increasing to severe coughing paroxysms, inspiratory
“whoop” and facial petechiae; post-tussive emesis
Paroxysmal phase (2–5 weeks)
Stages of pertussis
_________ ≥ 2 weeks of gradual resolution of cough
Convalescent phase
Gold standard for pertussis Dx
Gold standard is PCR of nasopharyngeal aspirate 2–4 weeks after onset of cough,
or a culture
Tx of Pertussis
Always treat if suspected or confirmed: erythromycin for 14 days (other macrolides
with similar results) only decreases infectious period of patient
− Most common cause of lymphadenitis lasting >3 weeks
– Cutaneous inoculation (arthropod borne by cat flea); kittens transmit better than
cats
Bartonella (Cat-Scratch Disease)
Pathognomonic sign of Bartonella (Cat-Scratch Disease)
One or more 3- to 5-mm red to white papules along the linear scratch
plus hallmark: chronic regional lymphadenitis
Tissue Dx of Cat scrath disease
Tissue: PCR and Warthin-Starry stain (shows gram-negative bacilli)
Tx of Cat scrath disease
Treatment—Antibiotics not used as there is a discordance between in vitro and in
vivo activity (use only for severe hospitalized cases) (usually self-limiting and resolves
in 2–4 months); aspiration of large and painful lesions
Most common vector-borne disease in the United States
Borrelia burgdorferi
SSX of Lyme disease
history of tick bite is helpful but absent in most; tick is small and often not seen by human eye; history of being in the woods or mountains should give suspicion
Early local findings of Lyme
Local: erythema migrans
often called “bulls-eye” rash;
target lesion (must be >10 cm in diameter)
Natural course of erythema migrans
without treatment, lesion resolves in 1–2 weeks
Early disseminated: secondary lesions of Lyme
smaller than the primary + constitutional
symptoms + lymphadenopathy; uveitis and Bell palsy (may be only finding); carditis
(myocarditis, heart block); CNS findings (neuropathy, aseptic meningitis
Late Lyme disease manifestations
arthritis weeks to months later; affecting large joints, more likely to be
chronic in adults
Dx of Lyme
– No definitive tests
– Primarily clinical and based on history + rash
Confirmatory of Lyme
Quantitative ELISA test and confirmatory Western blot if the ELISA is positive or
equivocal
Tx of Lyme
Doxycycline 14–21 days (patients >8 years old); amoxicillin (patients
age <8 years)
Tx of Lyme with meningitis or carditis (heart block)
Ceftriaxone
Tx of Lyme with Bell palsy
Doxycycline or amoxicillin
Consider in differential diagnosis of fever, headache, and rash in summer months,
especially after tick exposure
Rickettsia Rickettsii
Characteristic of rash of Ricketsia
After third day—skin rash º Extremities first (palms, soles) º Spreads rapidly º Becomes petechial/hemorrhagic º Palpable purpura
Cx of ricketsia
Vascular obstruction, due to vasculitis and thromboses, leads to gangrene
Tx of ricketsia
Treatment—doxycycline or tetracycline in all patients regardless of age (chloramphenicol
in allergy only)