Encephalopathy /ɛnˌsɛfəˈlɒpəθi/ means disorder or disease of the brain . [2] In modern usage, encephalopathy does not refer to a single disease, but rather to a syndrome of overall brain dysfunction; this syndrome can have many different organic and inorganic causes.

Terminology

Encephalopathy is a difficult term because it can be used to denote either a disease or finding (i.e., an observable sign in a patient).

When referring to a finding, encephalopathy refers to permanent (or degenerative) [7] brain injury, or a reversible one. It can be due to direct injury to the brain, or illness remote from the brain. The individual findings that cause a clinician to refer to a patient as having encephalopathy include intellectual disability, irritability, agitation, delirium, confusion, somnolence, stupor, coma and psychosis. As such, describing a patient as having a clinical picture of encephalopathy is not a very specific description.

When referring to a disease, encephalopathy refers to a wide variety of brain disorders with very different etiologies, prognoses and implications. For example, prion diseases, all of which cause transmissible spongiform encephalopathies , are invariably fatal, but other encephalopathies are reversible and can have a number of causes including nutritional deficiencies and toxins.

Signs and symptoms

The hallmark of encephalopathy is an altered mental state. Depending on the type and severity of encephalopathy, common neurological symptoms are loss of cognitive function, subtle personality changes, inability to concentrate, lethargy, and depressed consciousness. Other neurological signs may include involuntary grasping and sucking motions, myoclonus (involuntary twitching of a muscle or group of muscles), asterixis ("flapping tremor" of the hand when wrist is extended), nystagmus (rapid, involuntary eye movement), tremor , seizures , jactitation (restless picking at things characteristic of severe infection), and respiratory abnormalities such as Cheyne-Stokes respiration (cyclic waxing and waning of tidal volume), apneustic respirations and post-hypercapnic apnea .

Causes

There are many types of encephalopathy. Some examples include:

Diagnosis

Blood tests , cerebrospinal fluid examination by lumbar puncture (also known as spinal tap), brain imaging studies, EEG , and similar diagnostic studies may be used to differentiate the various causes of encephalopathy.

Diagnosis is frequently clinical. That is, no set of tests give the diagnosis, but the entire presentation of the illness with nonspecific test results informs the experienced clinician of the diagnosis.

Treatment

Treatment varies according to the type and severity of the encephalopathy. Anticonvulsants may be prescribed to reduce or halt any seizures. Changes to diet and nutritional supplements may help some patients. In severe cases, dialysis or organ replacement surgery may be needed.

Prognosis

Treating the underlying cause of the disorder may improve or reverse symptoms. However, in some cases, the encephalopathy may cause permanent structural changes and irreversible damage to the brain. These permanent deficits can be considered a form of stable dementia . Some encephalopathies can be fatal.

See also