LETARGIA. – A hypnoid state that may be observed in the course of organic diseases of the nervous system (epidemic encephalitis, sleeping sickness), in hysteria (v.), in nervous forms (v.), and in hysteria in particular; in the latter, it is sometimes related to convulsive crises, but often independent of them.
In spontaneous forms, after an initial phase of headache, though not constant, the patient suddenly falls into a deep sleep (hysterical apoplexy of Debove and Achard) or else lapses into drowsiness and apathy that progressively intensify until the state of lethargy is reached. At a superficial examination, the individual appears simply asleep; in reality, muscular relaxation is not complete, the muscles of mastication are slightly but distinctly contracted, and a fine palpebral tremor is frequent. In some cases, catatonic schizophrenic states have been mistaken for lethargy. The face may be pale or even livid; in general, the pulse and respiration are slow, to the point of respiratory arrest lasting several minutes (apparent death in hysterics). In a case cited by Binswanger from Pfendler, respiration ceased for 48 hours with the disappearance of all signs of life; in such cases, tragic errors may occur (v. MORTE). Examination of sensitivity shows complete anesthesia; sometimes, however, stimulation of hyperesthetic zones provokes reflex defensive movements that may interrupt the crisis. Moreover, during lethargy, spontaneous movements, probably automatic, are also observed; cutaneous and corneal reflexes may be abolished, while tendon reflexes are usually preserved.
The individual usually swallows food placed in the mouth; at times, however, pharyngeal and esophageal reflexes are absent, making feeding difficult. Awakening is sudden or gradual, accompanied by laughter, weeping, or disconnected speech. Amnesia for everything that occurred during the state is frequent, though not rarely patients recall with precision what took place around them. The duration of lethargy may vary from hours to days; in Krauss’s case, it reached 32 days; Jolly speaks of hysterical sleep lasting for months, Pfendler for years. Authors of the second half of the last century (Briquet, Charcot, Richer) distinguished three hypnoid states (catalepsy, lethargy, somnambulism) and various types of lethargy; today such subdivisions seem too artificial, and a unitary framework within hypothalamic vegetopathies is preferred.
Lethargy is classically observed in the oculo-letargic form of von Economo’s epidemic encephalitis, in which the patient is seized by marked drowsiness from which he can be relatively easily aroused; upon awakening, he is oriented, but left to himself, he falls back into the lethargic state; often he falls asleep again as soon as his position is changed, sometimes while eating. In this disease, lethargy may alternate with states of agrypnia (persistent insomnia), with considerable restlessness, especially at night. In the second stage of sleeping sickness (African trypanosomiasis, caused by Trypanosoma gambiense transmitted by the bite of the tsetse fly), a state of lethargy is frequent, generally intense, often irreversible and resistant to treatment.