Cirrhosis can envelop the liver if chronic hepatitis advances to end-stage liver disease. Experts estimate that at least half of those with cirrhosis have some degree of hepatic encephalopathy, and research demonstrates that this combination could increase the risk of driving mishaps.
When chronic hepatitis progresses to cirrhosis, an array of additional health concerns can surface. One of the most feared complications of cirrhosis, hepatic encephalopathy, appears to be hard to detect in its early stages. Interfering with a person’s concentration and reaction time, even a slight affliction with this condition poses a major risk for those driving a motor vehicle.
Hepatic encephalopathy (HE) is brain and nervous system damage that can occur as a complication of liver disorders. Ranging from mild to severe, HE causes different nervous system symptoms including changes in:
As seen in cirrhosis, toxic buildup results from reduced blood circulation in the liver. Although the exact cause of HE is unknown, experts concur that it stems from excessive poisons in the bloodstream damaging the central nervous system.
In people with otherwise stable liver disorders, HE may be triggered by:
· gastrointestinal bleeding
· eating too much protein
· renal disease
· medical procedures that bypass blood past the liver
· electrolyte abnormalities (especially a decrease in potassium) – potentially resulting from vomiting, paracentesis or taking diuretics
Hepatic encephalopathy may also be triggered by any condition that results in:
· alkalosis – when there is excess base (alkali) in body fluids
· low oxygen levels in the body
· use of medications that suppress the central nervous system (such as barbiturates or benzodiazepine tranquilizers)
· co-occurring illness
Stages of HE
As liver impairment progresses, an increasing amount of circulating toxins become available for nervous system damage. Likewise, the degree of neurological damage done is characterized in incremental stages. One of the hallmark tests to distinguish hepatic encephalopathy staging is asterixis, otherwise known as flapping tremor. Asterixis is defined by the University of Washington Division of Gastroenterology as the intermittent lapse of posture of the outstretched hands. By using this and other markers, the stages of HE are as follows:
· Stage 0 = Considered sub-clinical, there are no grossly evident changes in personality or behavior, except by special tests of central nervous system function. In addition, there is no asterixis.
· Stage 1 = In this stage, asterixis may be present. Characteristic symptoms are a shortened attention span, impaired handwriting and ability to perform simple arithmetic, impaired sleep and memory and altered mood.
· Stage 2 = Stage 2 is characterized by lethargy and/or apathy, disorientation, inappropriate behavior, slurred speech and obvious asterixis.
· Stage 3 = Evidenced by gross disorientation, semi-stuporous or stuporous behavior, in HE stage 3, asterixis may be difficult to elicit.
· Stage 4a = At this late stage of HE, the patient is in a frank coma. Seizures may occur with fulminant liver failure.
· Stage 4b = When HE is fatal, herniation of the swollen cerebrum protrudes through the base of the skull (foramen magnum).
Evidence Linking Driving Mishaps With HE
In a study divulged in the October 2007 edition of the Journal of American Gastroenterology, researchers evaluated over 100 participants with cirrhosis and compared their motor vehicle accident and traffic violation history to healthy controls. After excluding those from the study taking medication that could potentially interfere with driving ability, participants with cirrhosis, especially those with the early stages of HE, had significantly more motor vehicle accidents and traffic.
Although an estimated 20 to 85 percent of people with cirrhosis develop HE, those in the beginning stages are not always aware of their own central nervous system damage. While everyone with cirrhosis does not have HE, the majority will likely have some evidence of the beginning stages upon specified testing.
According to the study’s authors, “It is well known that hepatic encephalopathy is a complication of cirrhosis. However, the spectrum of impact associated with this complication is not as well recognized by clinicians who care for these patients. Although patients with this complication may have very recognizable and overt evidence of impairment, others may exhibit changes in cognitive function that are too subtle to be detected by the standard neurologic status assessments. Such abnormalities are apparent only with neurophysiologic and neuropsychological testing.” These comments suggest that specific tests are the only way to realize that central nervous system injury is occurring, and that there is an increased risk associated with driving.
What to Look For
If you have cirrhosis but haven’t been evaluated by a neurologist for HE, it is helpful to be familiar with some of this ailment’s earliest signs. Delays in reaction time and abnormal response inhibition are characteristic of stage 1 HE, and can easily impair a person’s driving ability. The generally recognizable symptoms of this stage of brain dysfunction include:
· shortened attention span
· impaired handwriting
· impaired ability to perform simple arithmetic
· impaired sleep and memory
· altered mood
Based on this study, repeated motor vehicle accidents or traffic violations may eventually be added to this list.
If liver disease has progressed to cirrhosis, determining if there is any affect on the brain can help a person make choices to enhance their own wellness and safety. Whether your changes in mood and behavior are or are not indicative of HE, the statistics underlie a need for those with cirrhosis to be extra cautious whenever driving a car.
Bajaj JS, et al, Minimal Hepatic Encephalopathy in Cirrhotic Patients and Its Association with Traffic Violations, American Journal of Gastroenterology, September 2007.
Worobetz, LJ, First Principles of Gastroenterology, (p. 537), AstraZeneca Canada Inc., 2000.
www.medscape.com, Is Minimal Hepatic Encephalopathy Associated With Increased Risk for Motor Vehicle Accidents and Traffic Violations?, David A. Johnson, MD, FACG, FACP, Medscape, 2007.
www.nlm.nih.gov, Hepatic Encephalopathy, National Institutes of Health, 2007.
www.uwgi.org, The Liver and Biliary System: Hepatic Encephalopathy, University of Washington Division of Gastroenterology, 2007.