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Letters to the Editor Indian Pediatrics 2003; 40:1212-1213 |
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1. None of the previous authors have used the criteria of ‘four to five years of symptoms’ before making a diagnosis of Hirayama disease(1). Even in the study quoted by Dr. S. Kumar(2) the duration of illness at presentation ranged from 3- 64 months with 25% patients having duration of illness less than 12 months. Given the reported arrest of disease progression with the use of a cervical collar(2), it is imperative that the diagnosis is made as early as possible rather than waiting for a period of "at least 4-5yrs. of symptoms". 2. The patient reported had asymmetric bilateral involvement with more severe wasting on the right side. The ‘oblique atrophy’ referred to is due to the wasting of the forearm and hand muscles with sparing of the brachioradialis. 3. We agree that the disease is uncommon in females. However, female sex alone does not exclude the diagnosis. 4. The disease usually presents in teens or early twenties and the earliest reported age at onset is 10 years, as mentioned in the text. The purpose of the case report itself was to comment on the early age of presentation and to speculate on the possible role of lead in accelerating the rate of disease progression (and thereby an early onset). 5. Hirayama, et al. studied 73 consecutive patients with the disease by myelography, CT-myelography and MRI(3). In neutral neck position, MRI could detect mild to moderate atrophy of lower cervical cord in only 49% of the patients (23 of 47). Genetic analysis of patients with distal upper limb spinal muscular atrophy has been previously carried out(4). In four patients of this disease which were studied, no homozygous deletions of exon 7 and 8 of the SMNtel gene were found, and no deletions in exon 5 of the NAIP gene were detected. The diagnosis is essentially clinical supplemented by results of electrophysiological investigations and muscle biopsy. Even though the parents were unwilling to go for further tests, we think that genetic studies would not have been of any help in the diagnosis. We have discussed the possibility of elevated lead being a coincidental finding. Chelation therapy was offered but refused by the parents. Devendra Mishra, |
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