Spondylitic myelopathies: One of the most common causes of gait difficulty in the elderly. Presents as neck and shoulder pain with stiffness, radicular arm pain, and progressive spastic paraparesis with paresthesias and loss of vibration sense; in advanced cases, urinary incontinence may occur. A tendon reflex in the arms is often diminished at some level. Diagnosis is best made by MRI. Treatment is surgical (Chap. 48. Back and Neck Pain).

Vascular malformations: An important treatable cause of progressive or episodic myelopathy. May occur at any level; diagnosis is often suggested by contrast-enhanced MRI (Fig. 188-3), but is confirmed by selective spinal angiography. Treatment is embolization or surgery with occlusion of the major feeding vessels.

Retrovirus-associated myelopathies: Infection with human T-cell lymphotropic virus I (HTLV-I) may produce a slowly progressive spastic paraparesis with variable pain, sensory loss, and bladder disturbance; diagnosis is made by demonstration of specific serum antibody. Treatment is symptomatic. A progressive vacuolar myelopathy may also result from HIV infection.

Syringomyelia: Cavitary expansion of the spinal cord resulting in progressive myelopathy; may be an isolated finding or associated with protrusion of cerebellar tonsils into cervical spinal canal (Chiari type 1). Classic presentation is loss of pain/temperature sensation in the neck, shoulders, forearms, or hands with areflexic weakness in the upper limbs and progressive spastic paraparesis; cough headache, facial numbness, or thoracic kyphoscoliosis may occur. Diagnosis is by MRI; treatment is surgical and often unsatisfactory.

Multiple sclerosis: Spinal cord involvement is common and is a major cause of disability especially in progressive forms of MS (Chap. 190. Multiple Sclerosis).

Subacute combined degeneration (vitamin B₁₂ deficiency): Paresthesias in hands and feet, early loss of vibration/position sense, progressive spastic/ataxic weakness, and areflexia due to associated peripheral neuropathy; mental changes and optic atrophy may be present along with a serum macrocytic anemia. Diagnosis is confirmed by a low serum B₁₂ level, elevated levels of homocysteine and methylmalonic acid. Treatment is vitamin replacement beginning with 1 mg of IM vitamin B₁₂ repeated at regular intervals or by subsequent oral treatment.

Hypocupric myelopathy: Clinically nearly identical to subacute combined degeneration (above) except there is no neuropathy. Low levels of serum copper and usually ceruloplasmin make the diagnosis. Some cases are idiopathic and others follow GI procedures that hinder absorption; excess zinc ingestion is another cause. Treatment is oral copper supplementation.

Tabes dorsalis (tertiary syphilis): May present as lancinating pains, gait ataxia, bladder disturbances, and visceral crises. Cardinal signs are areflexia in the legs, impaired vibration/position sense, Romberg sign, and Argyll Robertson pupils which fail to constrict to light but accommodate.

Familial spastic paraplegia: Progressive spasticity and weakness in the legs occurring on a familial basis; may be autosomal dominant, recessive, or X-linked. More than 30 different loci identified.

Adrenomyeloneuropathy: X-linked disorder that is a variant of adrenoleukodystrophy. Usually, affected males have a history of adrenal insufficiency and then develop a progressive spastic paraparesis. Female heterozygotes may develop a slower progressive myelopathy without adrenal insufficiency. Diagnosis made by elevated very long chain fatty acids in plasma and in cultured fibroblasts. No therapy is clearly effective although bone marrow transplantation and nutritional supplements have been tried.