DOCUMENTATION IV

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MOTOR NEURON DISEASESI. General Medical Background

A. Definition A group of conditions or diseases that produce dysfunction of the motor neurons, resulting in weakness and muscle wasting.

These include diseases or conditions that affect the upper (corticobulbar and corticospinal) motor neurons, the bulbar and spinal lower motor neurons, or both.B. Classification

Motor neuron diseases can be classified in a number of ways.

For easier grasp of the concept of motor neuron diseases, it will be presented here based on the location of pathophysiological involvement:a. Upper Motor Neuron Disorders Primary lateral sclerosis

Tropical spastic paraparesis

Lathyrism

Epidemic spastic paraparesis

Familial (hereditary) spastic paraplegia

b. Combined Upper and Lower Motor Neuron Disorders Classic amyotrophic lateral sclerosis (ALS)

Familial ALS

Western Pacific ALS parkinsonism dementia complex

Groote Eylandt motor neuron disease

Postencephalitic (encephalitis lethargica) ALS Juvenile inclusion body ALS

c. Lower Motor Neuron Disorders Spinal (bulbospinal muscular) atrophies Infantile forms of spinal or bulbospinal muscular atrophies

Acute infantile spinal muscular atrophy

Chronic infantile spinal muscular atrophy

Juvenile and adult forms of spinal or bulbospinal muscular atrophies Juvenile and adult proximal spinal muscular atrophy

Bulbar disease of childhood

Distal spinal muscular atrophy

Adult forms of bulbar and bulbospinal muscular atrophies Scapuloperoneal (fascioscapuloperoneal) muscular atrophy Chronic bulbospinal muscular atrophy of late onset

Monomelic (segmental) spinal muscular atrophy

Monoclonal gammopathy and motor neuron disease

Cancer and motor neuron disease

Poliomyelitis and post-polio syndrome

C. Epidemiology

The incidence of MND is approximately 15 out of 100,000 people.

Men have a slightly higher incidence rate than women.

Approximately 5,600 cases are diagnosed in the U.S. every year.

By far the greatest risk factor is age, with symptoms typically presenting between the ages of 50-70.

Most common motor neuron disease worldwide is amyotrophic lateral sclerosis. In 2000, the Philippines and the Western Pacific was declared poliomyelitis-free. However, survivors of poliomyelitis infection, particularly of the paralytic type, who undergo post-polio syndrome are the main concerns for rehabilitation.D. Etiology

The cause(s) of most motor neuron diseases are unknown, but some factors have been implicated, such as: Environmental

Toxic

Viral

GeneticE. Pathophysiology / Pathomechanics

Each motor neuron disease has its own sites of predilection. Pathophysiologic changes may vary but all affect the motor neurons which undergo processes of degeneration. Skeletal muscles are innervated by a group of neurons (lower motor neurons) located in the ventral horns of the spinal cord which project out the ventral roots to the muscle cells. These nerve cells are themselves innervated by the corticospinal tract or upper motor neurons that project from the motor cortex of the brain.

On macroscopic pathology, there is a degeneration of the ventral horns of the spinal cord, as well as atrophy of the ventral roots. In the brain, atrophy may be present in the frontal and temporal lobes.

On microscopic examination, neurons may show spongiosis, the presence of astrocytes, and a number of inclusions including characteristic "skein-like" inclusions, bunina bodies, and vacuolisation.

There is a role in excitotoxicity and oxidative stress, presumably secondary to mitochondrial dysfunction.F. Clinical Manifestation(s) Symptoms may include:

Difficulty swallowing Limb weakness Slurred speech Impaired gait Facial weakness

Muscle cramps Additional signs/symptoms may be present which are specific to each motor neuron disease.G. Complication(s) Respiration problems may occur but this usually happens in the later stages of the disease. Death is usually due to respiratory complications. Other complications are primarily due to loss of neuromusculoskeletal function, such as: Atrophy Contractures

H. Diagnosis

The diagnosis of motor neuron disease is made from a physical examination, an EMG study, and a pattern of finding and excluding other diseases which allows a physician, particularly a neurologist, to establish a diagnosis and to determine which form of the disease is present.

I. Differential Diagnosis

Motor neuron diseases may manifest as upper, lower, or combined upper and lower motor neuron lesion signs/symptoms. To differentiate, the following table may be useful:Upper Motor Neuron LesionLower Motor Neuron Lesion

WeaknessSpasticFlaccid

AtrophyNo significant atrophySignificant

Fasciculations / fibrillationsAbsentPresent

ReflexesHyperreflexiaHyporeflexia

Babinskis SignMay be presentAbsent

If a mixture of the above signs occurs, the lesion would most probably be a combined upper and lower motor neuron disease. Furthermore, it is best to tabulate the different motor neuron diseases to be able to compare each particularly as to the following:d. Definitione. Epidemiology, particularly demographic factorsf. Etiologic factor(s)

g. Pathophysiology

h. Clinical manifestation(s), including peculiarities

i. Possible complications

j. Useful diagnostic procedures

k. Prognosis

J. Prognosis

The prognosis for people living with a motor neuron disease varies depending on the type.

For somesuch as people with ALSthe outcome is terminal.

At this time there is no cure for motor neuron disease Over the last ten years, it appears that people with motor neuron diseases are living longer because of improved care and increased knowledge of the disease.II. Medical Management

K. Pharmacologic

L. Medical / Surgical

III. Physical Therapy Examination, Evaluation & Diagnosis

M. Points of Emphasis in Examination

N. Problem List

O. Physical Therapy Diagnosis

IV. Physical Therapy Prognosis (including Plan of Care) & Intervention

P. Plan of Care

Q. Interventions