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Carpal tunnel syndrome (CTS) is the commonest entrapment neuropathy, often idiopathic, and sometimes secondary to a variety of aetiologies, rarely infectious. We present three cases of CTS arising in the course of infection by Brucella melitensis, and responding to specific antibiotic treatment. As far as we know, these are the first reported cases implicating brucellosis in the pathogenesis of CTS.
Brucellosis is endemic in northwestern Greece. Among the numerous cases diagnosed and treated in the past 2 years, three patients presented with clinical symptoms suggestive of CTS, unilateral numbness and tingling sensation in the distribution of the median nerve.
On clinical examination, all three patients had positive Tinel’s and Phalen’s signs, and history, clinical, and laboratory examination excluded other possible causes of secondary CTS. No other neurological complications were noted. The diagnosis was confirmed by nerve conduction studies which, in one of the patients, apart from sensory fibres, elicited also a mild delay in the distal motor latency. The diagnosis of brucellosis was based on a consistent clinical picture and positive serology (Wright’s agglutination test >1/320, and positive enzyme linked immunosorbent assay (ELISA) serology). The first patient concurrently exhibited generalised weakness, the second patient was considered to have chronic brucellosis with a relapse presenting with fever, arthritis, and malaise, and the third patient presented with relapsing fever and polyarthritis, affecting the wrist. All three patients reported that CTS symptoms presented concurrently with the symptoms attributed to the disease.
All three patients were treated exclusively for brucellosis, one with doxycycline and rifampicin, and two with doxycycline and ciprofloxacin. The patients reported resolution of the symptoms when treatment ended at 6 weeks, and were further evaluated 3 months later with no evidence of relapse. Repeat nerve conduction studies were normal.
Although CTS is the commonest entrapment neuropathy encountered,1,2 many aspects of its aetiology remain obscure.3 Often termed as idiopathic, CTS can none the less be attributed to a variety of underlying disorders and processes,4 while random reports of CTS secondary to infectious diseases5–7 also exist.
Brucellosis remains a significant burden for many developing countries. Although the disease is usually readily diagnosed and treated, it can present with a variety of focal complications, or exhibit, especially if mistreated, a chronic course.
Neurological complications in the course of brucellosis are unusual.8 Peripheral neuropathy is rarely reported.9 Entrapment neuropathies though have never before been reported in association with brucellosis.
Various pathogenic mechanisms can be proposed for the appearance of CTS in the course of brucellosis, as illustrated by the three cases we present. The first of our patients seemed to have acute brucellosis, with a concurrent flexor tenosynovitis, resulting in median nerve compression and CTS. The second patient had chronic brucellosis, which is characterised by granuloma formation, development of which in the median nerve canal might result in the evolution of CTS. The third patient presented with polyarthritis affecting the wrist, with the resulting inflammation presumably implicated in the pathogenesis of CTS.
There is no way of knowing whether the median nerve dysfunction was secondary to a local mononeuritis or peripheral neuropathy, and no tissue was obtained to confirm a pathological diagnosis of flexor tenosynovitis associated with Brucella. It would seem unreasonable to perform an invasive procedure for the sake of scientific curiosity, because our patients responded readily to antibiotic treatment.
We conclude by emphasising the importance of including brucellosis in the differential diagnosis of secondary CTS in countries where the disease is endemic, because the variety of its clinical presentation, both in the acute and chronic form of the disease, can often be troubling.
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