Motor Neurone Disease (MND)

 

High profile (Stephen Hawking), but very rare. ICD-9: Ninth Revision of the International Classification of Disease provides comprehensive coding system for use in classifying medical data.

 

MND (3-digit) code is 335 - (anterior horn cell disease).

 

The more specific 4-digit codes

 

335.0: Wernig-Hoffman disease

335.1: Spinal muscular atrophy. Chronic disease of adolescents and young adults

335.8: Other types

335.9: Residual category of unspecified types

 

Note: cycad nut (sago palm is a source of edible flour in Guam) poisoning (toxin) and high-incidence focus of MND and Parkinsonism MND is a group of related anterior horn cell diseases of the CNS distinguished primarily by initial symptoms.

 

Spinal cord compression, some rare cancers, neuropathy and other diseases of CNS have similar symptoms and should be excluded in the diagnosis. Sporadic disease (no familial history of condition) in 85-90% of cases. MND includes:

 

     Amyotrophic Lateral Sclerosis (ALS)

 

     Wernig-Hoffman disease (infantile Spinal Muscular Atrophy)

 

     Kugelberg-Welander (both juvenile and adult forms of SMA)

 

     Progressive Bulbar Palsy (PBP)

 

     Progressive Muscular Atrophy (PMA)

 

Involves degeneration of the anterior horn cells, nerves in the CNS that control muscle activity. Degeneration cannot be halted. Invariably fatal and has no cure.

 

Amyotrophic Lateral Sclerosis (ALS). ALS accounts for about 80% of all cases. 1000 new cases /year diagnosed in England and Wales. This represents about 2 per 100000 of population. Current estimates are prevalence is about 6 to 12 in 100,000 have disease. A family doctor unlikely to encounter more than 2 cases in an entire career. About 1000 deaths a year accounts for 0.2% of all deaths. MND inevitably involves a neurologist. Symptoms include muscle weakness, wasting, cramps and fasciculations (irregular and involuntary contractions of muscle bundles) but these are not unique to MND. Fasciculation strong evidence of MND may also result from other spinal cord disease such as cervical myclopathy (spondylosis).

 

One form of MND resulting in progressive weakness of limbs. Initial symptoms are weakness in hands or legs and often fasciculation of the affected muscles. Whichever limbs affected first, all four limbs are eventually affected. Symptoms similar to Primary Lateral Sclerosis (PLS) - a rare neurological disorder characterised by progressive weakness of the muscles of the face, arms and legs. Loss of neurological function occurs slowly and results in spastic movements of the hands, feet and/or legs. Inability to walk follows. Sensory function and intellectual capabilities generally unaffected.

 

Kugelberg-Welander Syndrome (Benign Spinal Muscular Atrophy). Rare inherited neurological disorder. Form of MND with juvenile onset and long course Characterised by progressive degeneration of the motor neurones. Symptoms include progressive weakness and loss of muscle tissue, especially in legs and uncoordinated gait. Typically accompanied by loss of reflexes in the legs. Maybe lose bowel control and experience difficulty climbing stairs. Focal Motor Neurone Disease affects only one area of body, most commonly the shoulder girdle. Progressive over several months leaving patient with a fixed impairment of function. Some later develop more extensive MND. If Focal MND is considered as a diagnosis, care should be taken to exclude other causes of focal atrophy.

 

Progressive Bulbar Palsy (PBP) - variant of ALS. Weakness and wasting (atrophy) of muscles innervated by cranial nerves (lips, tongue and voice box). Initial symptoms ore difficulty speaking and swallowing.

 

Progressive Muscular Atrophy (PMA) - variant of ALS involves lower motor neurones. Weakness and wasting of muscles in lower body, particularly the legs. If upper motor neurone symptoms not occur (within 2 years usually) then unlikely that ALS will develop.

 

Pseudobulbar Palsy (PP) - variant of ALS characterised by spastic muscle weakness and loss of muscles innervated by cranial nerves (tongue, throat and face). Eyes not affected. Benign Focal Amyotrophy - variant where muscle weakness and wasting limited to single limb. Early symptoms may resemble ALS.

 

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