Human intestinal spirochetosis

Whenever biopsy material obtained from endoscopically normal colorectal mucosa reveals the blue haematoxyphilic line between the microvilli of the covering epithelium, the rare condition of intestinal spirochetosis is diagnosed. The classification of the bacteria detected with the aid of special stains (e.g. the Warthin Starry silver stain) and in the electron microscope, continues to be something of a problem. A further point of contention is the question whether this spirochetal infection is of pathological significance or not. A point militating against pathogenicity is the fact that no histological signs of an inflammatory reaction are to be seen. Also, the symptoms of patients with intestinal spirochetosis are such that they provide no basis for a pronouncement on whether the infection is of a pathological or apathological nature. On the other hand, however, a number of studies do seem to indicate that the spirochetes might be the cause of such symptoms as diarrhoea, constipation and abdominal pain. A point that would appear to support this view is the fact that such symptoms may disappear after successful treatment with metronidazole. The histological diagnosis is easily established when, faced by an apparently normal histological appearance of the colorectal mucosa,the pathologist considers the possibility of spirochetosis, and undertakes a specific search for the blue haematoxyphilic line in the covering epithelium of the colorectal mucosa.