Letargia

Letargia is a state of reduced arousal and responsiveness, lying between wakefulness and sleep. It is a symptom rather than a distinct disease, signaling an underlying medical, metabolic, or environmental cause that dampens wakefulness or alertness.

Signs and symptoms include marked drowsiness, slow speech and movements, reduced attention and reaction time, and diminished responsiveness to stimuli. In some cases response to pain may be blunted. Letargia can occur with varying depth of consciousness and may progress to stupor or coma if the underlying condition worsens.

Common causes are broad and include medical illnesses (infections such as sepsis or meningitis; metabolic disturbances like hypoglycemia, hyponatremia, hepatic or renal failure; endocrine disorders such as hypothyroidism or adrenal insufficiency), neurological events (stroke, brain tumor, intracranial hemorrhage, CNS infections), medications or substances (benzodiazepines, opioids, sedatives, alcohol, illicit drugs), sleep deprivation, dehydration, and malnutrition. Age, chronic illness, and acute stress can increase risk.

Evaluation typically involves a clinical history and physical examination, vital signs, and targeted investigations. Basic tests may include blood glucose, electrolyte panel, kidney and liver function, complete blood count, infection markers, and, if indicated, urine analysis, imaging studies, lumbar puncture, or drug screens. Differential diagnosis includes fatigue, somnolence, delirium, stupor, and coma.

Management focuses on diagnosing and treating the underlying cause while ensuring patient safety. This may entail airway and breathing support, hydration, correction of metabolic abnormalities, antimicrobial therapy when appropriate, adjustments of sedating medications, and supportive care. Prognosis varies with the etiology and timeliness of intervention.