This is a progressive disease of unknown origin in which there is degeneration of motor neurons of the spinal cord and cranial nerve nuclei and of pyramidal neurons in the motor cortex.

CAUSES:

👉 95% of the cases – Viral infection, trauma, exposure to toxins and electric shock. (Though no Strong evidence exists)

👉 5% of the cases – Familial showing autosomal dominant inheritance. Defect lies in Chromosome 21 on the enzyme SOD1 (Superoxide dismutase)

CLINICAL FEATURES:

👩‍⚕️ Usually affects people above 50 years of age. Very uncommon before 30.

👨‍⚕️ Male predominance.

👩‍⚕️ Dysarthria and Dysphagia.

👨‍⚕️ Wasting and fasciculation of muscles.

👩‍⚕️ Weakness of tongue, face, palate and limb muscles.

👨‍⚕️ Spasticity, extensor plantar reflexes and excessive tendon reflexes are seen in case of pyramidal tract involvement.

👩‍⚕️ External ocular muscles and sphincters usually remain intact.

👨‍⚕️ No sensory deficit objectively seen.

👩‍⚕️ Intellectual impairment is not seen in most cases.

INVESTIGATIONS:

🧐 Differential diagnosis: diabetic amyotrophy, multifocal neuron disease, spinal disorders should be excluded.

🧐 Electromyography – helps confirm fasciculation and denervation.

🧐 Spinal imaging and brain scanning – to exclude focal spinal or cerebral disease.

🧐 A slightly elevated protein concentration is seen in the CSF examination sometimes.

MANAGEMENT:

💊 Riluzole 100 Mg per day appears to be modestly effective in prolonging the life of the patient.

💊 Helps the Quality of life of patients: Psychological and physical support, speech therapist, physiotherapist.

💊 Mechanical aids: Splints, wheelchairs, walking aids, communication devices.

PROGNOSIS:

⚠️ Motor Neuron Disease is progressive; the mean time from diagnosis to death is 1 year.

⚠️ Most patients die within 3-5 years after the onset of symptoms.

⚠️ Death is usually from respiratory infection and failure, and the complications of immobility.

SOURCE: Davidson’s Principles and Practice of Medicine (19th edition)

---

~Sunantha✍️