Sensory disturbances are frequently present. They consist in local areas of hyperæsthesia, more frequently of anæsthesia, numbness of the hands and fingers or of the feet, formication of the surface of the body and limbs, and burning or neuralgic pains in the face, chest, and extremities. The pains in the limbs are almost characteristic. They are acute and persistent, neuralgic in character, but not localized to particular nerve-tracts. They are more common in the legs than in the arms, and occupy by preference the calves of the legs and the flexor muscles between the elbows and the wrists. They do not implicate the joints, are not aggravated to any grave extent by movement, and are often temporarily relieved by gentle frictions. The pains of chloralism have been described as like encircling bands above the wrists and ankles.
Sensations of chilliness alternating with flashes of heat are experienced. The temperature is, in the absence of complications, normal. Excessive doses are followed by a reduction of one or more degrees Fahrenheit, lasting several hours.
Among the motor disturbances are the following:
Tremor.—This symptom is not common. It is neither so pronounced nor so distinctly rhythmical as that of alcoholism or the opium habit. It is increased upon voluntary effort. It affects chiefly the hands and arms and the tongue.
Palsy.—Loss of power in the lower extremities has been observed in a number of instances. It varies in degree from paresis to complete paraplegia. Its occurrence may be gradual or sudden. It passes away upon the discontinuance of the habit. In many respects this condition resembles alcoholic paraplegia.
Impairment of Co-ordinating Power.—Ataxic phenomena are sometimes present. The patient has difficulty in walking in the dark, cannot stand with his eyes closed, has trouble in buttoning his clothes, and the like.
Impairment or Abolition of the Knee-jerk.—In a man aged fifty, who had taken thirty to sixty grains of chloral hydrate at night for eighteen months, the writer observed complete loss of the knee-jerk, which, however, reappeared in the course of a few weeks after the discontinuance of the drug.
In rare cases epileptiform seizures have occurred.
Chloral produces in certain individuals, even as the result of a single dose, congestion and irritation of the conjunctiva. Apart from this idiosyncrasy, its habitual use not infrequently causes conjunctivitis. This affection is occasionally of a severe grade and accompanied by œdema of the eyelids and great photophobia. Retinal congestion has been noted by several observers. Amblyopia, disappearing upon the cessation of the habit, has also been observed.