Medical Archive

Tick-, mite-, louse-, and flea-borne rickettsioses

?? : ???? ???? ?/??/???? ??  (cf. Q fever : ????)
?? : vasculitis (cf. Q fever : granuloma)
?? : fever, headache, centrifugal rash (?? ? ??), eschar

Q fever : no rash
Rocky-mountain fever : centripetal rash
?? : ?? ?? (cf. scrub typhus)

Epidemic typhus	R.prowazekii	Louse feces	Rash avoids palms, soles & face (centrifugal)	Serology +/- Weil-Felix test TC, Ch
Rocky-mountain spotted fever	R.rickettsii	Tick, mite bite	Maculopapular rash on palms & soles (centripetal)	Serology +/- Weil-Felix test
??? (endemic) Murine typhus	R.typhi (texas, california)	Flea	?? O, ?? X
????? Scrub typhus	O.tsutsugamushi (asia, pacific)	Mite	??? ??, eschar ?? ?? ?? ?? ?? O, ?? O	DC, AM, Ch
Human monocytic ehrlichiosis	E.chaffeensis	Tick
Q fever	Coxiella burnetii	Not necessary	? ??+???? ? ??. ???? ?? X, ?? X	Serology, (-) Weil-Felix test DC, TC

Rocky mountain spotted fever RMSF

R.rickettsii, Tick-borne
Attacks vascular endothelial cells.

• Clinical features
  • 3-4 days of constitutional symptoms (nonspecific fever, headache, myalgia, arthralgia)
  • Maculopapular rash on palms & soles (centripetal)
  • Life-threatening noncardiogenic pulmonary edema (eg, bilateral rales) and shock (eg, hypotension, tachycardia, poor arousal) can occur.
• Lab findings
  • Thrombocytopenia d/t intravascular platelet destruction
  • Hyponatremia d/t increased ADH d/t hypovolemia
• Lumbar puncture
  • Mild leukocyte elevation (eg, <100/mm3), minimal protein elevation, and normal glucose
  • cf) dramatic leuckocytosis (eg, >1,000/mm3) in meningococcal meningitis.
• Treatment
  • Doxycycline – recommended in all patients, including in children, in whom the risk of dental staining is minimal with the sourt courses (eg, 5-7 days) used for RMSF.

Mediterranean spotted fever (Boutonneuse fever), African tick-bite fever, and other tick-borne spotted fevers

Tick-born
R.conorii, R.africae, R.parkeri, R.japonica, R.sibirica, R.heilongjiangensis, R.australis

Rickettsialpox

R.akari

Flea-borne spotted fever

R.felis

Epidemic (louse-borne) typhus

R.prowazekii, Louse-borne
Rash avoids palms & soles & faces (centrifugal)

Endemic murine typhus

R.typhi, flea-borne

Scrup typhus

O.tsutsugamushi, mite-borne

??? ? 3? ?? ??, ??, ??
??? ??? ?? ???? ?
non-specific ??? ??. CRP? ADA? ????.
??? ??? ?? ??? ??/??? ?? (nested PCR? ??? ? ??)
?? ??? ?? ?? – IFA (?florescent Ab)  (but ????? ?? 2?? ???? ?? ??
?)
??: Doxycycline, Chloramphenicol (???): Rifampicin, Azithromycin “Delacroix”
Ag? ???? ??? ?? ? ?? X but Doxycycline?? ?? ??
Shock, ???? ?? Cx?? ??? ??.

Ehrlichioses and anaplasmosis

D/t ixodes tick.

Human monocytotropic ehrlichiosis

E.chaffeensis, tick-borne

Harbored by white-tailed deer in the southwestern, southeastern, and mid-Atlantic US.

Replicates in vacuoles within monocytes and forms mulberry-shaped, intraleukocytic inclusions (morulae).

• Clinical manifestations
  • Flu-like illness (eg, fever, chills, myalgia)
  • Neurologic symptoms (confusion)
  • Not often associated with a rash (<30% in adults, maculopapular)
  • Leukopenia ± thrombocytopenia, ?LFTs & LDH

Ewingii ehrlichiosis and ehrlichia muris eauclairensis infections

“Candidatus neoehrlichia mikurensis” infection

Human granulocytotropic anaplasmosis

Q fever

?? ????? ?? ?? (???, ??? ????? ??)

1. Inhalation of bacteria from air contaminated by animal waste.
2. Acute Q fever
   • Nonspecific febrile illness: >10 days of fatigue, and myalgias 
   • Retroorbital headache associated with photophobia, frequent.
   • Pneumonia; lobar consolidation is m/c.
   • Normal leukocyte count, ?liver enzyme, thrombocytopenia
3. Chronic Q fever
   • Infective endocarditis in patients with valvular disease.
   • Frequently fatal if not treated.
   • May occur in patients with or without previous symptomatic acute infection

??, ?? ?? Doxycycline / ???: Cotrimoxazole