The Many Causes of Encephalopathy

Encephalopathy is a broad term that refers to diseases affecting the structure or function of the brain. There are a lot of causes of encephalopathy, and it takes many forms; some are present from birth, and others appear much later in life. The condition may resolve when the underlying cause is treated, or it could cause permanent damage or worsen over time.

Wernicke Encephalopathy

Wernicke encephalopathy results from inadequate thiamine levels and carbohydrate ingestion. The most common underlying factor is extreme alcohol intake, which interferes with thiamine absorption in the gut; however, it may result from any condition that causes vitamin B1 deficiency. Neurological changes appear suddenly and include sluggish or unequal pupils, hearing loss, confusion, short steps, and a wide gait.

Chronic Traumatic Encephalopathy

Chronic traumatic encephalopathy (CTE) results from repeated head injuries. Symptoms do not appear right away, often taking years to begin and getting worse over time. They include mood problems and issues with concentration. Studies show that CTE is very common in athletes, especially American football players.

Hashimoto’s Encephalopathy

The cause of Hashimoto encephalopathy is unknown, but experts believe it is related to an autoimmune abnormality. Symptoms vary from person to person but often include confusion, change of mental status, visual hallucinations, and paranoid delusions. Doctors treat the condition with cortisone or immunosuppressive therapy, and with proper treatment, the symptoms typically resolve or improve within a few months of onset.

Hypertensive Encephalopathy

Hypertensive encephalopathy is a rare hypertensive emergency. Patients at risk for this type of encephalopathy have uncontrolled primary hypertension with blood pressures as high as 220/120. Cerebral edema occurs, resulting in symptoms like headaches, seizures, vomiting, restlessness, confusion, balance problems, and, if untreated, coma. These issues typically resolve after the doctor treats the patient to lower their blood pressure.

Glycine Encephalopathy

Glycine encephalopathy is a recessive genetic disorder caused by a buildup of the amino acid glycine in the body, especially in the cerebrospinal fluid. Most patients with this type of encephalopathy have symptoms in the first few days after birth, including lethargy, decreased tone, and jerking. This can progress to apnea and often death. Babies who survive often live with severe mental defects and seizures. There are also mild forms and a late-onset variant, where children present with progressing spastic paralysis with their intellectual functions intact.

Hepatic Encephalopathy

Hepatic encephalopathy can occur in people with liver dysfunction. Blood is not properly filtered in the liver, leading to a buildup of ammonia and other toxins. Signs include a change in mental status, personality changes, intellectual impairment, and in severe cases, cerebral edema and brain stem herniation.

Toxic Metabolic Encephalopathy

Toxic metabolic encephalopathy occurs when something toxic or poisonous prevents the brain cells from behaving normally. Hypoxia, malnutrition, dehydration, medications, environmental toxins, and infection can all cause this type. The prominent symptom is a change in mental status, but toxic metabolic encephalopathy can be difficult to diagnose because doctors must rule out other conditions first.

Infectious Encephalopathies

Infectious encephalopathies can be caused by viral, bacterial, fungal, or parasitic infection, though this is not always the case. This type of encephalitis is characterized by an acute onset of fever, neurological deficits, seizures, and altered mental status. That said, they can also present without fever, which makes diagnosis difficult. Identifying the pathogen is key to effective treatment.

Hypoxic Ischemic Encephalopathy

Hypoxic ischemic encephalopathy (HIE) is caused by a lack of oxygen. While an adult can experience this type of encephalopathy, it is most commonly the result of birth trauma or injury. Newborns with this type of encephalopathy present with a low Apgar score — a five-part newborn test — at delivery. Within 24 hours after birth, apnea and seizures may appear. HIE is the most common cause of cerebral palsy, and it occurs in two to nine of every 1,000 live births.

Uremic Encephalopathy

Uremic encephalopathy is an uncommon form that occurs in patients with acute renal injury or chronic kidney disease. Three types of uremic encephalopathy are classified by the affected part of the brain: cortical or subcortical involvement, basal ganglia involvement, and white matter involvement. Symptoms include sleep disorders, headaches, gait disturbances, nausea, daytime drowsiness, confusion, restlessness, and difficulty speaking.