Motor Neuron Disease

Motor neuron disease, an adult-onset progressive neurodegenerative disorder, with a variable rate of progression, presents with advancing weakness of the extremities and bulbar and respiratory muscles. Biological pathways implicated in the etiology of MND include glutamate toxicity, mitochondrial dysfunction, and misaggregation of abnormally folded protein. Approximately 10% of cases are inherited as an autosomal dominant trait. Management of MND ideally involves a multidisciplinary team. The unhelpful nihilism often encountered by many patients due to its unfortunate fatal outcome, with death typically occurring between 3 and 5 years post-diagnosis, has now been replaced by a more positive symptomatic approach focusing on symptom relief and preservation of independence and quality of life. Riluzole, a glutamate antagonist, is currently used as the disease-modifying therapy. The management principles also include optimization of nutrition, respiratory care, and symptomatic treatment of spasticity and cramps, excessive salivation, and emotional lability. Clinical variants, natural history, etiology, pathology, clinical manifestations, and medical, surgical, and physiotherapy management are discussed in this chapter.