In 1888, Henry Strachan, a British medical officer stationed in Jamaica, described a syndrome of painful peripheral neuropathy, ataxia, optic neuropathy, and stomatitis among sugar cane workers.^ Denny-Brown and others found similar ailments among allied troops liberated from prisoner-of-war camps after World War II. In these patients, other symptoms included sensorineural deafness, dizziness, confusion, spastic leg weakness, foot drop, Wernicke's encephalopathy, and rare cases of neck extensor weakness and myasthenic bulbar weakness. Poor nutrition, hard physical labor, and concurrent infection were thought to be exacerbating factors. In Fisher's autopsy series of Canadian prisoners of war, the most prominent pathological finding was demyelination of the posterior columns of the thoracic and cervical spinal cord. y This demyelination accounted for the loss of vibratory and position sense and sensory ataxia. Pathologically, the optic and auditory nerves showed moderate to severe demyelination.
More recently, an outbreak of optic and peripheral neuropathy closely resembling Strachan's syndrome occurred in Cuba in 1992 to 1993, following the loss of food and fuel exports.y Fifty thousand people developed isolated or combinations of optic neuropathy, painful sensory neuropathy,
dorsolateral myelopathy, sensorineural deafness, spastic paraparesis, dysphonia, and dysautonomia. Almost half (45 percent) developed centrocecal scotoma and optic neuropathy only, often following a period of weight loss. Optic neuropathy and myeloneuropathy were seen in 24 percent, optic neuropathy and sensorineural hearing loss in 14 percent, and peripheral and optic neuropathies with hearing loss in 7 percent. y Proposed mechanisms included vitamin B complex and thiamine deficiency, cyanide intoxication, viral infection, and mitochondrial deletion. Infections appeared to precipitate or exacerbate symptoms. Almost all patients responded to early supplementation with B complex vitamins. Evidence for peripheral nerve involvement has been mixed. Clinical evidence of neuropathy is often lacking despite severe symptoms. Fisher examined the peripheral nerves in 2 of 11 patients at postmortem and found no abnormalities; however, nerve teasing and modern histopathological techniques were not used. Osuntokun documented peroneal nerve conduction slowing and normal conductions of the median and ulnar nerves, y whereas Borrajero found abnormal sural nerve action potentials only in the most severely affected individuals. y Sural nerve biopsies showed axonal degeneration of large myelinated fibers.
Extensive study of the epidemiology of the Cuban outbreak revealed smoking, weight loss, sugar consumption, and excessive alcohol intake as risk factors. Urban men 25 to 64 years of age were most affected. Pregnant women, children, and the elderly were minimally affected; however, these groups were targeted for supplementation before the outbreak. Women were more likely to develop paresthesias in the feet, whereas men were more likely to develop optic neuropathy. y In Africa, pregnant women are most vulnerable,y and smoking and weight loss were the strongest risk factors for the optic neuropathy variant.
This clinical syndrome should be distinguished from beriberi, vitamin B 12 deficiency, pellagra, tropical spastic paraparesis (human T-cell lymphotropic virus-1 [HTLV-1]), tropical ataxic neuropathy of Africa, subacute myelo-optic neuropathy, clioquinol ingestion in Japan, Leber's optic neuropathy, and nutritional amblyopia. In order to do so, dietary and family histories; vitamin B12 , folate, and transketolase levels; medication history; and an HTLV-I assay should be obtained.
Treatment consists of re-establishing a balanced diet with B complex vitamin and vitamin A supplementation. In the Cuban experience, long-term sequelae were rare, because most had early treatment with nutritional supplements, including B complex and vitamin A. In prisoners of war with longstanding symptoms, persistent ataxia, burning feet, and visual defects often persisted despite adequate supplementation.
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