Amyotrophic lateral sclerosis- A review

Abstract

Amyotrophic lateral sclerosis (ALS) is a rare neurodegenerative disease, rapidly progressive, invariably fatal motor neuron disease attacking neurons controlling voluntary muscles. It is characterized by muscular paralysis reflecting degeneration of motor neurons in brain stem, corticospinal tract, primary motor cortex and spinal cord. Most ALS cases are sporadic but few (5-10%) cases are familial. The cause is not known in 90-95% cases and about 5-10% cases are genetically inherited. The mean age of onset of sporadic ALS is 60 years. Overall studies suggest that males are affected more than females. Prevalence and incidence of ALS is relatively uniform. Approximately 2/3^rd of patients with typical ALS have spinal form (limb onset) and present symptoms related to focal muscle wasting and weakness. Gradually spasticity may develop in weakened limbs, affecting gait mainly. Patients with bulbar onset ALS present usually limbs symptoms, dysphagia for solids and liquids, dysarthria symptoms may develop simultaneously with bulbar symptoms and in majority of cases it occur within 1-2 years. ALS is diagnosed on the basis of clinical history, physical examination, skin biopsy, lumbar puncture. The main pathological feature comprise loss of motor neuron with interneuron- ubiquitin, TDP-43 immunoreactive inclusions in degenerating lower neurons. The management of ALS include symptomatic treatment, ventilatory support and nutritional management. Non- invasive ventilation improves survival rate and quality of life. Till date Riluzole is the only drug that has shown to lengthen survival of the patients.