Encephalopathy Health Article

Symptoms

The hallmark of encephalopathy is altered mental state. In mild cases, hypoxia can cause an altered mental state, which includes symptoms such as motor incoordination, poor judgment, and inattentiveness. Mild cases have no lasting effects. Patients who have severe hypoxia or anoxia (total lack of oxygen delivery, usually from cardiac arrest) lose consciousness within seconds. Other symptoms of encephalopathy include lethargy, nystagmus (rapid, involuntary eye movement), tremor, dementia, seizures, myoclonus (involuntary twitching of a muscle or group of muscles), muscle weakness and atrophy, and loss of ability to speak or swallow. An early and characteristic feature of hepatic encephalopathy is called constitutional apraxia, which is inability to reproduce simple designs such as a star. Patients with liver failure may exhibit a symptom called asterixis, an involuntary jerking tremor of the hands.

Diagnosis

The diagnosis of encephalopathy depends on the presence of acute or chronic liver disease; altered mental state such as confusion, stupor, or coma; symptoms of central nervous system damage; and abnormal wave patterns on an encephalogram. Diagnostic tests that may be utilized to establish the diagnosis include, but are not to limited to: complete blood count; liver function tests; ammonia and glucose levels; lactate levels (often elevated due to impaired tissue perfusion and because of decreased clearance by the liver); arterial blood gases (may reveal hypoxemia); kidney function tests; blood cultures (to detect infectious agents); virology testing (for hepatitis); neuroimaging studies; and ultrasound studies.

Treatment team

The causes of encephalopathies are broad. Additionally, the symptoms are also broad, ranging from mild changes of consciousness to coma or death. Therefore, the treatment team can consist of a broad spectrum of specialists that can include, but is not limited to, an internist, oncologist, pulmonologist, critical care physician, radiologist, hepatologist (specialist in liver diseases), and surgeon. The disorder can also occur in the pediatric ages or even at birth. In these critical situations, specialists in pediatric critical care, a neonatologist, and a perinatologist (specialist in maternal-fetal health) would be involved.

Treatment

Hypoxia or anoxic encephalopathy is an emergency, and immediate measures are necessary to prevent further damage to the brain and to restore breathing and circulation. It is necessary to treat hepatic encephalopathy early to prevent long-term damage. Specific treatment for hepatic encephalopathy is aimed at eliminating toxic substances and/or treatment of the primary illness that caused encephalopathy. Elimination of toxins such as ammonia can be accomplished by decreasing absorption of protein from the gut. By giving the patient a compound called lactulose, absorption of ammonia can be decreased. Persons with hepatic encephalopathy should not consume protein, and constipation should be avoided. Uremic encephalopathy caused by chronic renal failure is treated with transplantation or dialysis.

Recovery and rehabilitation

Recovery is an emergency for all patients with severe hypoxia or anoxia. Vital functions such as breathing, cardiac function, and delivery of oxygen-rich blood to the brain should be restored within two to five minutes. If anoxia persists for more than two minutes, there will be permanent and severe damage to the brain.

Clinical trials

There are four active government-sponsored clinical trials that are recruiting patients. There is a phase III clinical trial concerning birth asphyxia (hypoxic-ischemic encephalopathy) in infants up to six hours old. A phase II clinical trial is investigating the neuroimaging findings associated with persistent encephalopathy caused by the tick-transmitted infection called Lyme's disease (persistent Lyme encephalopathy). A third study is investigating a genetic form of familial dementia that causes encephaolpathy due to neurodegeneration of brain tissue. A fourth study investigates a disorder called neuronal ceroid lipofuscinosis (NCLS), which is a common heritable form of encephaopathy that occurs in one of 12,500 children. Detailed information about each of these studies can be obtained online from the website <http://www.clinicaltrials.gov>.

Prognosis

The outcome for patients who present with symptoms of encephalopathy depends on the cause. If the cause can be corrected in time, the outcome can be favorable. However, if encephalopathy is a manifestation of more advanced chronic disease, or if it is part of a rapidly fulminating disorder, the outcome can be poor and death may ensue due to the primary cause.

Special concerns

Persons who present with encephalopathy have advanced disease or the beginning of an advanced disease process. Vigilance on the part of the primary care provider is necessary to take all precautions to prevent this process.

BOOKS

Goetz, Christopher G., et al. (eds). Textbook of Clinical Neurology, 1st ed. Philadelphia: W.B. Saunders Company, 1999.

Goldman, Lee, et al. Cecil's Textbook of Medicine, 21st ed. Philadelphia: WB. Saunders Company, 2000.

Noble, John, et al. (eds). Textbook of Primary Care Medicine, 3rd ed. St. Louis: Mosby, Inc., 2001.

Rakel, Robert A. Textbook of Family Practice, 6th ed. Philadelphia: WB Saunders Company, 2002.

Rosen, Peter. Emergency Medicine: Concepts and Clinical Practice, 4th ed. St Louis: Mosby Year Book, Inc., 1998.