The pathophysiology of delirium remains poorly understood. Risk factors for delirium are cognitive status, demographics, functional status, sensory impairment, decreased intake, drugs, medical comorbidity, primary neurological diseases, environmental, prolonged sleep deprivation, intercurrent illnesses and surgery.

In practical terms, delirium seems to involve an interaction between baseline vulnerability and precipitating factors. Delirium is more common in the elderly because they tend to be more vulnerable at baseline. For a vulnerable elderly person who may have impaired cognition and hearing, and multiple chronic conditions, a single sleeping pill may be enough to trigger delirium.

 

On electroencephalography, patients with delirium show a generalized slowing of background activity, consistent with widespread cortical dysfunction. While the degree of slowing correlates grossly with degree of cognitive impairment, it is nonspecific in terms of underlying etiologies. The slowing pattern reverses when the clinical delirium resolves. Medications are the most common contributors to delirium in the elderly and are the most easily reversible cause.

 

 By Lucy Varghese - 2007