Encephalopathy means disorder or disease of the brain. Encephalopathy refers to a syndrome of overall brain dysfunction; which in the case of Lyme encephalopathy is caused by Lyme disease.
The hallmark of encephalopathy is an altered mental state. Characteristic is impairment of cognition, attention, orientation, sleep-wake cycle, and consciousness.
Encephalopathy was not included in the CDC case definition of Lyme disease which means there is no agreed-upon definition. In 1990 Logigian and colleagues listed the chronic neurologic abnormalities of Lyme encephalopathy as memory loss, depression, sleep disturbance, irritability and difficulty finding words.
Coyle and colleagues from State University New York, Stony Brook Medical School, conducted a prospective, controlled study to characterize neurologic and neurobehavioral manifestations of Lyme disease in the North America.
Those with chronic disease had a different constellation of major symptoms, such as concentration difficulties, fatigue, mood disturbance, memory loss, sleep problems, word-finding difficulties, confusion and stiff neck. They had more cognitive, mood, and joint disturbances; more severe symptoms; and more current depression, anxiety, and adjustment problems.
However, it was the acute disease patients who were more likely to show objective cognitive deficits. However, objective tests often do not agree with patients perceptions. This is especially true for memory in depression.
A study from Logigian in 1997 concluded that if a definition of Lyme encephalopathy is restricted to cognitive testing, it fails to identify 38% of the patients with central nervous system abnormalities.
Signs of Lyme encephalopathy
Signs of central nervous system involvement have included abnormalities in the cerebrospinal fluid such as pleiocytosis, abnormal brain scans such as single photon emission computed tomography (SPECT), magnetic resonance imaging (MRI) or electroencephalogram (EEG), antibody production in the cerebrospinal fluid or a positive polymerase chain reaction (PCR) for Borrelia burgdorferi DNA or a positive culture.
Patients often complain of 'brain fog' to describe the effects of Lyme encephalopathy. Symptoms such as concentration problems, memory problems, word-finding difficulties, depression, anxiety and other mood disturbances, sleep problems and stiff neck are often reported and can all be manifestations of Lyme encephalopathy.