DISCITIS: AN IMPORTANT CONSIDERATION IN PYREXIA OF UNKNOWN ORIGINS

Abstract

Diagnosis of infective discitis may be difficult as presentation is usually non-specific with little symptomatology and few signs in the early stages. This dilemma is further complicated by the fact there is a long latent period between the onset of symptoms and plain radiograph changes and a high index of suspicion must be maintained. We reviewed 30 cases referred to our unit for treatment between 1996 and 2001 with an emphasis on time to diagnosis.

90% of patients complained of some degree of back pain at initial presentation and 70% had symptoms of active infection. 60% had a history of recent sepsis and a further 23% had been extensively investigated for pyrexia of unknown origin (PUO).

The mean time to diagnosis from first presentation to a member of the medical profession was 54 days (range 0–183 days). 35% of patients were diagnosed incidentally on a CT scan while investigating abdominal and chest symptoms or PUO so these diagnoses could potentially have been delayed further.

23% of patients required acute surgical treatment and in this sub-group the mean time to diagnosis was 61 days (range 14–91 days).

16% of patients died as a result of discitis. In this subgroup the mean time to diagnosis was 74 days (range 56–183 days).

Many patients were extensively investigated for PUO or sepsis of unknown cause despite having persistent back pain. Although a small sample, delay in diagnosis seems to increase death rates. Many of these patients had first presented to their general practitioner or a physician for investigation, however discitis is rarely cited as a differential diagnosis of PUO in medical textbooks.

A high index of suspicion must be maintained in patients with back pain, especially that of a non-mechanical nature. Discitis should be considered early in such patients especially those with evidence of infection. Discitis must always be included in the differential diagnosis of pyrexia of unknown origin.