What is Motor Neurone Disease

In motor neuron disease (MND) there is relentless and unexplained destruction of lower and upper motor nerve fibres in the brain and spinal cord, leading to progressive weakness of muscles.

Statistics on Motor Neurone Disease

MND affects 4-6 people out of every 100 000. MND usually presents in middle age and is slightly more common in men.

Risk Factors for Motor Neurone Disease

The cause of MND is unknown. In 5-10% of cases there is a family history, but this is often not the case.

Progression of Motor Neurone Disease

MND has a gradual onset. 70% of patients present with progressive and symmetric limb weakness. This often begins as a foot drop, although deficits in fine hand movements may be noticed first. Localised pain may precede the onset of muscle weakness and wasting by several weeks; this may be severe in late stages of the disease.

The natural history of MND is progressive muscle weakness culminating in death usually from respiratory failure. Patients who are artificially ventilated, fed via gastrostomy and receiving full nursing care may have their life prolonged for a several months albeit in a totally dependent condition.

How is Motor Neurone Disease Diagnosed?

Diagnosis is usually clinical – there is no specific test for diagnosing MND. Investigations which may be helpful include:

  • Electromyographic and nerve conduction studies may help with the exclusion of other possible causes.
  • MRI scan
  • A Muscle biopsy is occasionally performed
  • Blood investigations
  • Lumbar puncture

Prognosis of Motor Neurone Disease

MND will progress gradually and will invariably cause death usually from respiratory failure or bronchopneumonia. Survival for more than 3 years after onset is unusual although some patients may survive for over a decade.

How is Motor Neurone Disease Treated?

There is no cure for MND, and treatment is aimed at enabling the patient to remain independent as long as possible and controlling symptoms to ensure a reasonable quality of life. A multidisciplinary approach, with input from with input from various sources including GP, neurologist, occupational therapist, physiotherapist, social worker and psychologist is essential.

No treatments have been shown to influence the outcome of the disease however Riluzole (a sodium channel blocker that decreases glutamate release from astrocytes and neurons) has been shown to slow progression of the disease slightly.

Treatment of patients with MND may also involve gait assistive devices (orthotics, walkers), electric wheelchairs, speech assistive devices and suitable food preparations (eg. pureeing food). Gastrostomy may be performed in those with more severe swallowing difficulties.

(Kindly reviewed by Dr. Matthew Kiernan PhD FRACP Associate Professor in Neurology, Prince of Wales Medical Research Institute & Prince of Wales Clinical School, University of New South Wales. Consultant Neurologist, Institute of Neurological Sciences, Prince of Wales Hospital Sydney.)

Motor Neurone Disease References

  1. Braunwald, Fauci, Kasper, Hauser, Longo, Jameson. Harrison’s Principles of Internal Medicine. 15th Edition. McGraw-Hill. 2001
  2. Cotran, Kumar, Collins 6th edition. Robbins Pathologic Basis of Disease. WB Saunders Company. 1999.
  3. Hankey G., Wardlaw J. Clinical Neurology. Demos Medical Publishing, United Kingdom, 2002.
  4. Haslet C, Chiliers ER, Boon NA, Colledge NR. Principles and Practice of Medicine. Churchill Livingstone 2002.
  5. Hurst JW (Editor-in-chief). Medicine for the practicing physician. 4th edition Appleton and Lange 1996.
  6. Kiernan MC. (2003). Motor neurone disease: a Pandora’s box. Med J Aust 7;178:311-2.
  7. Kiernan MC. (2005). Riluzole: a glimmer of hope in the treatment of motor neurone disease. Med J Aust 182:319-20. (Invited editorial).
  8. Kumar P, Clark M. CLINICAL MEDICINE. WB Saunders 2002 Pg 427-430.
  9. Longmore M, Wilkinson I, Torok E. OXFORD HANDBOOK OF CLINICAL MEDICINE. Oxford Universtiy Press. 2001
  10. McLatchie G and LEaper DJ (editors). Oxford Handbook of Clinical Surgery 2nd Edition. Oxford University Press 2002.
  11. Miller RG, Munsat TL, Swash M, Brooks BR. Consensus guidelines for the design and implementation of clinical trials in ALS. World Federation of Neurology committee on Research. J Neurol Sci 1999; 169: 2-12.
  12. Raftery AT Churchill’s pocketbook of Surgery. Churchill Livingsone 2001.
  13. Rosen DR, Siddique T, Patterson D, et al. Mutations in Cu/Zn superoxide dismutase gene are associated with familial amyotrophic lateral sclerosis. Nature 1993;362:59-62.
  14. Winhammar J.M., Rowe D.B., Henderson R.D., Kiernan M.C. (2005). Assessment of disease progression in motor neuron disease. Lancet Neurology 4:229-238 (Invited review).