Thread by @guerreroespejo

A 50-YO ♀️ bitten by her pet rat: fever, myalgia, sore throat, headaches a nonpruritic rash on extremities including palms & soles, arthralgias, knees arthritis.

A punctate wound with central necrosis on L palm, & her R thumb.
1/9

#rheumatology #internalmedicine #dermatology

Leukocytosis with neutrophilia
ESR & PCR:⬆️

Purulent R knee synovial fluid:
✔️46 000 cells/mL (88% neutrophils).
✔️Gram stain: scant pleomorphic gram-negative bacilli in chains with lateral bulbar swellings
2/9

doi.org/10.1093/cid/ci…
#microbiology #rheumatologist

Synovial fluid 🧫culture: Streptobacillus moniliformis identified by biochemical testing & confirmed by MALDI-TOF.

RAT BITE FEVER (RBF) WITH SEPTIC ARTHRITIS DUE STREPTOBACILLUS MONILIFORMIS
3/9

#bacteriology #IDtwitter #microbiología

Penicillin is the treatment of choice for RBF

The patient was treated with a 4-week course of intravenous penicillin G with complete resolution of her symptoms.
4/9

doi.org/10.1093/cid/ci…
#MedTwitter #primarycare #Doctor

Rat bite fever (RBF)
✔️a rare systemic zoonotic infection
✔️transmitted following a bite from a colonized rat.
✔️caused by Streptobacillus moniliformis, the most common worldwide whereas Spirillum minus, a spirochete, is the predominant cause in Asia
5/9

#medicine #MedEd

The incubation period is 3 days to 3 weeks

Streptobacillary RBF classically involves a triad of fever, rash, and polyarthritis

The arthritis can be monoarticular or polyarticular, & most commonly involves the knees
6/9

#dermtwitter #dermatología #resident

Approximately 2–4 days after symptom onset, patients frequently develop a diffuse rash that can be macular, papular, petechial, or pustular involving the extremities & affecting the palms and soles, but usually sparing the face & trunk
7/9

#dermpath #AtencionPrimaria

Symptoms resolve spontaneously in the majority of untreated patients, although some may have a relapsing and remitting course or persistent arthralgias

Potential complications including myocarditis, pericarditis, brain abscesses, and endocarditis
8/9

#healthcare #primarycare

Streptobacillus moniliformis:
✔️a fastidious organism,
✔️isolation may become more common with the use of modern, non-culture-based diagnostic techniques such as MALDI-TOF
9/9

#microbiology #bacteriology