Definition.—A hereditary disease, appearing between the third and fifteenth years, and characterized by ataxia, impaired speech, nystagmus or paraplegia, and accompanied by changes in the lateral and posterior columns of the spinal cord. Friedreich first described the disease in 1861.
Etiology.—Heredity.—Although a single case may occur in a family, the occurrence of two or more in the same family is characteristic, and ten cases have been reported in a single family. There is generally a history of consanguinity, nervous disorders, inebriety, or nervous irritability, and is probably due to defective or feeble development. The infectious fevers have preceded the disease, though most likely a coincidence rather than a possible cause.
Pathology.—The most characteristic lesion is the diminution in size of the spinal cord. There is extensive sclerosis in the posterior and lateral, columns of the cord, and degeneration to slight extent in the anterior columns. Extending upwards the sclerosis may involve the medulla.
Symptoms.—The first ataxic symptoms develop in the lower extremities, though the gait is somewhat different from locomotor ataxia. There is more of a swaying, staggering, or irregular gait, and less of a stamping character. When the upper extremities are involved, the movements are irregular and jerky, resembling chorea. Irregular movements may occur in arms or legs even when the patient is at rest. There may also be irregular swaying of the head.
Impairment of speech early develops. At first it may be difficulty in enunciation, as in stuttering, or a syllable or word is missed, until finally an unintelligible mumble results. Although the face is more or less expressionless, the intellect remains unaffected, though late in the disease there may be mental impairment. Romberg's symptom is generally present, and a peculiar deformity of the foot develops, known as the "pes cavus," a stumpy foot with the arch exaggerated, and the toes extended, the great toe being abnormally prominent. There may also be deformity of the hand.
Spinal curvature may also follow. The sphincters are not involved; there are no trophic changes in skin or joints, no optic neuritis, nor crises. Late in the disease paralysis appears.
Diagnosis.—Usually there is no difficulty in recognizing the disease, there generally being two or more cases in the same family; the age of the patient, between three and fifteen, the irregular shuffling gait, the deformity of the foot, and the imperfect speech, being characteristic.
Prognosis.—This is unfavorable as to cure, though the life may be prolonged twenty, thirty, or more years.
Treatment.—But little can be hoped for in treating this disease, other than in maintaining the general health. Hygienic measures, fresh air, and a liberal diet are to be secured.