30 Jun 2022

6/10/2021 – Rickettsia Typhi Infection

PGY2 Steven Luminais presented a case of 22 y/o male with PMH of obesity who presents from clinic with persistent fevers as high as 39.6C for 6 days. He reports ”dark” urine without dysuria, urinary frequency, back/flank over the same 6 days. He states he has a mild SOB, a dry cough, nausea w/ some vomiting, and frontal headache associated with dizziness.  Denies changes in PO intake and bowel habits. He has received 1 dose of COVID vaccine but deferred 2nd dose secondary to his current symptoms.

ROS: +fevers, +dizziness, +fatigue, +SOB, +nausea, +emesis (NBNB), +dark urine

PMH: None

PSH: None

Meds: PRN Ibuprofen for fevers/mild aches

Allergies: NKDA

FH: None

SH: Unemployed. Denies T/E/D. Lives in LA, no recent travel. Owns dogs, cats, and turtles in his apartment. No exposures to cows or sheep. No recent sexual activity. No recent changes in food habits.

Vital Signs:  T 39.2     HR 112     RR 25     BP 113/55     O2 sat 100% RA     Weight: 225 kg     BMI 66

Physical Exam: Morbidly obese, non-toxic appearing male. Significantly enlarged tonsils. Tachypneic on room air.

CBC: WBC 5.8>Hgb 12.7/Hct 36.8<Plt 82 (MCV 77, RDW 12.9)

Differential: Neutrophils 64%, 22% Bands, Lymphocytes 9%, Monocytes 5%, Eosinophils 0%, Basophils 0%


Na 132/K 3.2/Cl 96/HCO3 24/BUN 9/Cr 0.91<Glucose 116

ALP 48>T.protein 7.0/Albumin 3.9/AST 111/ALT 111/Tbili 0.9/Dbili <0.4

Ca 8.1. Mg 2.0, Phos 2.3

Coags: PT 16.0, INR 1.29, PTT 28.9

Infectious workup including BCx, UCx, RPR, HIV, hepatitis panel negative. Procal 3.75

Rickettsia typhi IgM: Detected, >1:256. Rickettsia typhi IgG: Detected, >1:256

Treatment: Started on doxycycline for presumed rickettsia infection. Discharged home on total 5 day course of doxycycline.

Image credit: NEJM Tweet: “Zoonotic Cycle of Rickettsia typhi”

Teaching Points:
•Presumptive diagnosis is largely made on history of flea bites/exposures
•Symptoms and labs are largely non-specific
•Low case fatality rate, though several related Rickettsia species can have a higher (>15%) mortality. •Intracellular organism will not respond to our typical first line agents; treatment is with Doxy vs. Azithro.

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