28 Sep 2020

8/26/20 Murine Typhus

PGY2 Philip Kingsford presented a case of a 50 y/o female with no PMH who presents with 11 days of worsening fevers, chills, diarrhea and abdominal pain.  She reports being in her usual state of health until 11 days prior to presentation.  She developed crampy abdominal pain worse on the L than R, that was associated with diarrhea, fevers and chills.  Over this time, she also developed muscular pain in her calves that was unchanged with movement.  These symptoms worsened over the following week which prompted her to present to the ED.  At that time, she was evaluated and sent home with thoughts this is due to nonspecific viral prodrome and was instructed to socially isolate.  Over the following few days, she developed worsening nausea without vomiting.  She reported mild dizziness and denied COVID exposure, history of travel, NSAID/Alcohol/drug use.  Denied weight loss, rash or group gatherings.

Social history pertinent for living in Pasadena, CA with husband and daughter and 2 dogs.  She is from Mexico but lived in the US for past 10 years.  Works in a Laundromat.

Vitals significant for T 36.9, HR 122, RR 23 and BP 103/66, satting 99% on RA.  Exam with tachycardia, diffusely tender to palpation of abdomen (LUQ mostly) and tenderness to palpation in b/l calves.

CBC: WBC 8.6 > Hb 12.9/Hct 35.7 <Plt 84

CMP:
Na 130/K 3.8/Cl 95/HCO3 21/BUN 8/Cr 0.67 <Glucose 185
ALP 144>T.protein 5.4/Albumin 3.4/AST 215/ALT 217/Tbili 0.6/Dbili 0.4

Coags:PT 13.9, INR 1.08

CK 509

TSH 2.65 (normal 0.27-4.20)

ANA negative

Infectious workup:

  • Lactate 3.2 (normal 0.5-2.2)
  • Procal 2.27
  • BCx negative x2
  • UA negative
  • UCx negative
  • Acute hepatitis panel negative
  • HIV negative
  • COVID negative
  • Flu panel negative
  • Stool studies:
    • Culture negative
    • O&P negative
    • C diff negative
  • Malaria negative
  • CSF studies:
    • Cell count: PMN 2, Glucose 61, Protein 26
    • CSF viral panel negative
    • CSF gram stain and culture negative
  • Rickettsia Typhi IgM >1:256, IgG >1:256

Inflammatory markers:

  • DDimer >20.00 (normal <0.29)
  • CRP 228 (normal <4.9)
  • LDH 678 (normal 135-225)
  • Ferritin 3588

RUQ US and CT A/P performed with no evident to account for patient’s clinical symptoms.

Treatment: Patient was started on doxycycline x10 days for concern of murine typhus.  Her liver enzymes climbed as high as AST 890/ALT 589 with no signs of synthetic dysfunction.  Patient was discharged on hospital day 5 after improvement in symptoms and was seen in outpatient PMD clinic 2 weeks later with complete resolution of symptoms and resolution of thrombocytopenia.  Lab check at one month post discharge, her hepatic function test has completely normalized.

Take home points:

  1. Murine typhus is a flea borne illness caused by Rickettsia typhi.  Typical onset of presentation occurs 7-14 days following exposure.  Symptoms include fever, headache, myalgias, abdominal pain, nausea/vomiting and rash.  The rash typically occurs at the end of the first week of illness and starts as a maculopapular eruption on the trunk and spreads peripherally, sparing the palms of the hands and soles of the feet.
  2. Typical lab findings: anemia, thrombocytopenia, leukopenia, hyponatremia and elevated levels of liver enzymes.
  3. Treatment of murine typhus is doxycycline.

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