There are several "neuromuscular diseases", (diseases involving pathology of the nerves affecting muscular function), that can have a large impact on the foot and lower extremity. We'll discuss several of the most common and well-known diseases:
Charcot Marie Tooth Disease
Charcot Marie Tooth Disease is an inherited, progressive neuromuscular disease. It affects men more than women by a ration of 5:1. It involves a muscular atrophy of both the lower extremities (feet and legs) and upper extremities (hands and arms), and patients have a classic appearance of thin "stork" legs, high-arched "cavus" feet and hammertoes.
Conservative treatment ranges from doing nothing in early or modest cases, to making special orthoses, toes splints, and AFO (ankle-foot-orthoses) braces. Surgical intervention to address the hammertoes, high-arched feet, and muscular weakness is sometimes necessary.
Dejerine Sottas Disease is clinically very similar to Charcot-Marie-Tooth Disease. It, too, is characterized by muscle weakness in the legs and feet, high-arched "cavus" feet, and hammertoes, drop foot, and diminished sensation and reflexes. Somewhat distinctive about Dejerine Sottas Disease is its tendency to cause visible enlargement of the nerves. Diagnosis is by nerve biopsy.
Treatment is the same as with Charcot-Marie-Tooth Disease.
Symptoms with Friedreich's Ataxia also mimic Charcot-Marie-Tooth Disease (muscle weakness, cavus feet, hammertoes, drop foot, diminished reflexes and sensation), though Friedreich's Ataxia tends to strike earlier--in childhood. Friedreich's Ataxia also progresses more rapidly and may lead to a greater degree of incapacitation by middle age. There is also an increased tendency for heart problems (hypertrophic cardiomyopathy).
Patients with Roussy-Levy Syndrome also have many of the same symptoms as Charcot-Marie-Tooth Disease, (muscle weakness, cavus feet, hammertoes, drop foot, diminished reflexes and sensation), though Roussy-Levy will commonly create tremors, particularly in the hands.
Resfum's Disease is a result of abnormal processing of the body's fats, causing huge increases in a compound known as phytanic acid. As with the other disease mentioned above, Resfum's Disease may cause muscle weakness, cavus feet, hammertoes, drop foot, diminished sensation and reflexes, but patient's with Resfum's Disease also tend to develop ichthyosis (severe thickening of the outer layers of the skin) and night blindness. The onset of Resfum's Disease is usually preceded by illness and high-fever.
Once a terrible scourge around the world, the polio virus affects the cells in the spinal cord, resulting in varying degrees of diminished reflexes, muscle wasting, weakness, and deformities in the lower extremity.
Myelodysplasia (Spina Bifida)
Myelodysplasia is a spinal cord defect where portions of the spine protrude from their normal location in the spinal cord. Myelodysplasia is most common in the lower lumbar and sacral vertebrae, which affects the nerves heading towards the feet. Symptoms of these conditions include varying degrees of diminished sensation, diminished reflexes, poor muscular tone and balance, ulceration, and bladder dysfunction.
There are four forms of myelodysplasia:
Muscular Dystrophy (MD)
Muscular Dystrophy is a well-known disease characterized by muscle wasting, diminished reflexes, contractures of the feet and altered gait. Diagnosis is usually made by laboratory tests, electromyography, nerve conduction studies and muscle biopsy. There are several types of Muscular Dystrophy with varying genetic causes, including:
Cerebral Palsy (CP)
Cerebral Palsy is a non-progressive disease caused by a lesion in the cerebral portion of the brain. The most frequent cause is from a period of diminished oxygen to a portion of the brain. There are four forms:
Tumours of the Spinal Cord
Tumours in the spinal cord may give a variety of symptoms in the lower extremities, depending upon where the lesion is located and which nerves are affected.