Description

A 19-year-old patient, without medical history, presented a first episode of continuous fever (about 39°C) for 14 days, with rash and arthromyalgia and functional impotence of the ankles for 7 days. Clinically, the patient had asthenia with ankle biarthritis with a predominantly palm-plant rash (Figure 1). Right ankle joint puncture finding inflammatory fluid (5300 nucleated elements/mm3 including 91% neutrophils), without microcrystals. Immunological test (rheumatoid factor and citrullinated anti-peptide antibodies) was negative. The skin biopsy performed in an area of pathological skin is in favor of an infectious origin, with microabscesses.

The patient had not travelled recently. He had several pet rats at home, one of which had been suffering from otorrhagia for several weeks. Blood cultures collected on the same day as the joint puncture came back positive for Streptobacillus MoMoniliformis (SM), while the joint puncture fluid remained sterile. SM is a commensal bacterium in rats, especially in the middle ear. The infectious clinical presentation could therefore be associated with the symptoms of the pet rat. The echocardiography did not find any argument for endocarditis, frequent with this germ.

The patient has recovered under antibiotic therapy (Doxycycline 200 mg/day during one month), with fever and oligoarthritis resolving within 48 hours, and the skin healing a little later. The patient has not had a recurrence to date.

Figure 1: Asthenia with ankle biarthritis with a predominantly palm-plant rash.