Hirayama Disease: the importance of the differential diagnosis in suspected neural leprosy
Pure neural leprosy, leprosy without skin manifestations, is common in leprosy. Patients with muscle weakness or paralysis without the classical leprosy cardinal signs, such as the typical skin lesions and skin smear positivity, are sometimes erroneously diagnosed as having neural leprosy. Sound knowledge of the innervation pattern of nerves that can become involved in leprosy can help differentiate pure neural leprosy from other neuromuscular conditions. Simple clinical testing procedures can aid in the differential diagnosis. When in doubt of a diagnosis, additional testing procedures can confirm or reject a diagnosis of neural leprosy. Hirayama Disease is a relatively rare disease of the lower cervical spine which presents mainly as paralysis of the forearm and hand muscles. We report four patients with Hirayama Disease referred to and diagnosed at one leprosy referral center. One patient was treated for leprosy before the diagnosis of Hirayama Disease. Clinical differentiation between the two neural diseases is relatively easy.