Lethargy is an extreme lack of energy along with drowsiness. This state can be a sign of great fatigue but also of a physical or mental illness. A lethargic state in the baby or the child is a warning sign and should lead to a prompt medical consultation. 

The word lethargy comes from the Greek lethée (forgetfulness) and argia (rest, inactivity). It indicates a state of inertia, drowsiness, extreme nonchalance. In medicine, this term is used to refer to a very significant decrease in the activity of a person. Lethargy is thus a state of extreme fatigue, a lack of energy, which leads to use the organism to a minimum, more or less marked by drowsiness. A lethargic state can be linked to fatigue but also reveal an underlying pathology. 

In adults, lethargy is manifested by significant inactivity, a life in slow motion or even drowsiness, abnormal and prolonged deep sleep.

In babies or children, lethargy can manifest itself by a number of signs: staring into space, great weakness (the child can no longer cry or cry, does not play, does not smile), loss of tone (he is limp and he does not hold his head when you try to sit him down), difficulty being awake, no reaction when talking to him). 

A lethargic state in a baby or a child should require urgent medical attention. 

Lethargy can have many causes, physical or mental. Fatigue linked to a poor lifestyle (late bed, alcohol or narcotics advice) can lead to a lethargic state. 

All serious illnesses can lead to lethargic state. Depression can also accompany lethargy. The end of life is also accompanied by a lethargic state with drowsiness, in the last weeks / days. 

When the lethargic state is linked to a physical illness the cause is treated. If lethargy is associated with depression, antidepressant therapy combined with therapy is initiated. 

If the lethargic state is linked to fatigue without a pathological cause, a change in lifestyle can make it possible to get out of the lethargic state: eat a healthy diet, practice regular physical exercise, make sure you get a sufficient amount of sleep , avoid narcotics and excessive alcohol consumption.