Lethargy - Causes and Symptoms

Definition

Lethargy is a pathological state characterized by deep sleep.

This condition is associated with:

Complete relaxation of muscle tone;
Slowing of psychic functions.
Absence or minimal ability to react to stimuli;

If awakened, the patient tends to go back to sleep immediately afterwards.

In severe cases, lethargy can develop into a comatose state.

The causes can be different. Lethargy is often due to injuries and pathologies of the nervous system that affect the hypothalamus-mesencephalic area, such as tumors, vascular accidents and infectious encephalitis (eg African trypanosomiasis).

Other possible causes are metabolic alterations, such as hypoglycemia, liver failure, acidosis, alcoholism and chronic carbon monoxide poisoning. Furthermore, this state of deep sleep can occur in the presence of hypothyroidism, anemia and polycythemia.

Lethargy can also fall within the symptomatic framework of some forms of depression.