Encephalopathy: Types, Causes, Symptoms, Stages & Treatment

Hepatic encephalopathy can occur when your liver stops filtering toxins from your blood.

• The causes ofencephalopathyare numerous and varied; they include infections, anoxia, metabolic problems, toxins,drugs, physiologic changes,trauma, and other causes.
• Encephalopathy is a general term that refers to brain disease, damage, or malfunction.
• The major symptom of encephalopathy is an altered mental state.
• Encephalopathy is often considered a complication of a primary problem such as alcoholiccirrhosis,kidney failure, or anoxia.
• Early treatment of many types of encephalopathy can eliminate, reduce, or halt the symptoms of encephalopathy.
• Often, cases of encephalopathy can be prevented by avoiding the many primary causes.
• There are several types of encephalopathy such as chronic traumatic encephalopathy (CTE) andhepatic encephalopathy.
• 慢性创伤性脑病(CTE):德generative disease of the brain (a form of brain damage) that occurs in athletes or others who have experienced repetitiveconcussionsor other trauma to the brain.

Encephalopathy is a term that refers to brain disease, damage, or malfunction. Encephalopathy can present a very broad spectrum of symptoms that range from mild, such as somememory lossor subtle personality changes, to severe, such asdementia,seizures,coma, or death.

In general, encephalopathy is manifested by an altered mental state that is sometimes accompanied by physical manifestations (for example, poor coordination of limb movements).

The term encephalopathy, in most cases, is preceded by various terms that describe the reason, cause, or special conditions of the patient that leads to brain malfunction. For example, anoxic encephalopathy means brain damage due to lack of oxygen, andhepatic encephalopathymeans brain malfunction due toliver disease.

Additionally, some other terms either describe body conditions or syndromes that lead to a specific set of brain malfunctions. Examples of these are metabolic encephalopathy and Wernicke's encephalopathy (Wernicke's syndrome). There are over 150 different terms that modify or precede "encephalopathy" in the medical literature; the purpose of this article is to introduce the reader to the main categories of conditions that fall under the broad term of encephalopathy.

The causes of encephalopathy are both numerous and varied. Examples of causes of encephalopathy include:

• infectious (bacteria,viruses, parasites, or prions),
• anoxic (lack of oxygen to the brain, including traumatic causes),
• alcoholic (alcoholtoxicity),
• hepatic (for example,liverfailure orliver cancer),
• uremic (renal orkidney failure),
• metabolic diseases (hyper- or hypocalcemia, hypo- or hypernatremia, or hypo- or hyperglycemic),
• brain tumors,
• toxic chemicals (mercury, lead, or ammonia),
• alterations in pressure within the brain (often from bleeding, tumors, or abscesses), and
• poornutrition(inadequate vitamin B1 intake oralcohol withdrawal).

These examples do not cover all of the potential causes of encephalopathy but are listed to demonstrate the wide range of causes.

Although numerous causes of encephalopathy are known, the majority of cases arise from several major categories (some examples in parentheses):

• infection (HIV,Neisseria meningitides,herpes, andhepatitis Bandhepatitis C),
• liver damage (alcohol and toxins),
• brain anoxia or brain cell destruction (including trauma), and
• kidney failure (uremic).

Some drugs may cause encephalopathy; for example, posterior reversible encephalopathy syndrome (PRES) may occur due to the use of drugs liketacrolimusandcyclosporine. This syndrome manifests with symptoms ofheadache,confusion, andseizures.

Despite the numerous and varied causes of encephalopathy, at least one symptom present in all cases is analtered mental state.The altered mental state may be subtle and develop slowly over years (for example, inhepatitisthe decreased ability to draw simple designs, termed apraxia) or be profoundly obvious and develop rapidly (for example, brain anoxia leading tocomaor death in a few minutes). Often, symptoms ofaltered mental statuscan present as inattentiveness, poor judgment, or poor coordination of movements.

Other serious symptoms that may occur include:

• lethargy,
• dementia,
• seizures,
• tremors,
• muscle twitching andmyalgia,
• Cheyne-Stokesrespiration(an alteredbreathingpattern seen with brain damage and coma), and
• coma.

Often the severity and type of symptoms are related to the severity and cause of the brain disease or damage. For example, alcohol-induced liver damage (alcoholiccirrhosis) can result in involuntaryhand tremors(asterixis), while severe anoxia (lack of oxygen) may result in a coma with no movement.

Other symptoms may not be as severe and maybe more localized such as cranial nerve palsies (damage to one of the 12 cranial nerves that exit the brain). Some symptoms may be very subtle and result from repeated injury to the brain tissue. For example, chronic traumatic encephalopathy (CTE), due to injuries like concussions repeatedly sustained by football players and others who play contact sports, may cause slow changes over time that are not easily diagnosed. Such injury may lead to chronicdepressionor other personality changes that can result in life-changing consequences.

Even infants and children can suffer encephalopathy. Similar symptoms can occur in the perinatal period if the neonate had any compromise to brain blood flow during its development.

• Rasmussen'sencephalitisis a rare disease that is seen in children that progresses to intractable seizures if untreated. It may be due to autoantibody development.
• Another rare form of encephalopathy that usually develops in younger people (about ages 4-20 years) is theMELAS syndrome("Mitochondrial Encephalopathy, Lactic Acidosis,Stroke-like episodes") due to faulty DNA in the patient's mitochondria (a tiny part within the cell that is responsible for energy conversion).

Diagnosis of encephalopathy is usually made with clinical tests done during the physical examination (mental status tests, memory tests, and coordination tests) that document an altered mental state. In most cases, findings on clinical tests either diagnose or presumptively diagnose encephalopathy. Usually, the diagnosis occurs when the altered mental state accompanies another primary diagnosis such as chronicliver disease, kidney failure, anoxia, or many other diagnoses.

Consequently, physicians may utilize several different tests at the same time to diagnose both the primary condition (the cause of encephalopathy) and the encephalopathy itself. This approach to diagnosis is done by most physicians, because encephalopathy is a complication that occurs because of a primary underlying health problem. The most frequently utilized tests are listed below with some of the major primary causes the tests may help diagnose the condition:

• Complete blood countorCBC(infections or loss of blood)
• Blood pressure(high orlow blood pressure)
• Metabolic tests (blood levels ofelectrolytes, glucose, lactate, ammonia, oxygen, andliver enzymes)
• Drugs or toxin levels (alcohol,cocaine,amphetamines, and many others)
• Blood and body fluid cultures and analyses (infections of many types)
• Creatinine(kidney function)
• CT andMRIscans (brain swelling, anatomical abnormalities, or infections)
• Dopplerultrasound(abnormal blood flow to tissues or abscesses)
• Encephalogram orEEG(brain damage or abnormal brain wave patterns)
• Autoantibody analysis (dementiacaused by antibodies that destroy neurons)
• Review of the person's medications as some medications (for example, cyclosporine) may be responsible for symptoms

This list is not exhaustive, and not all of the above tests need to be done on every patient. Specific testing is usually ordered by the treating physician according to the symptoms and history of the patient.

治疗脑病随primary cause of the symptoms. Consequently, not all cases of encephalopathy are treated the same.

Some examples of different "encephalopathy treatments" for different causes:

• Short-term anoxia (usually less than two minutes):Oxygen therapy
• Long-term anoxia:Rehabilitation
• Short-term alcohol toxicity:IV fluids or no therapy
• Long-termalcohol abuse(cirrhosis or chronic liver failure):Orallactulose, low-protein diet, antibiotics
• Uremic encephalopathy (due to kidney failure):To correct the underlying physiologic cause,dialysis,kidney transplant
• Diabetic encephalopathy:Administration of glucose to treathypoglycemiaandinsulinto treathyperglycemia
• Hypo- or hypertensive encephalopathy:Medications to raise (for hypotensive) or reduce (for hypertensive) blood pressure

The key to treatment of any encephalopathy is to understand the basic cause and thus design a treatment plan to reduce or eliminate the cause(s).

有一种diffic脑病ult or impossible to treat—static encephalopathy (an altered mental state or brain damage that is permanent). The best that can be done with static encephalopathy is, if possible, to prevent further damage and implement rehabilitation to allow the individual to perform at his or her highest possible functional level.

Complications of encephalopathy vary from none to profound mental impairments that lead to death. The complications can be similar in some cases. Also, many investigators consider encephalopathy itself to be a complication that arises from a primary health problem or primary diagnosis.

Complications depend on the primary cause of encephalopathy and can be illustrated by citing a few examples from the wide variety of causes:

• Hepatic (liver) encephalopathy (brain swelling with herniation, coma, death)
• 代谢encephalopathy (irritability, lethargy,depression, tremors; occasionally, coma or death)
• Anoxic encephalopathy (wide range of complications, from none in short-term anoxia to personality changes, severe brain damage to death in long-term anoxic events)
• Uremic encephalopathy (lethargy,hallucinations, stupor, muscle twitching, seizures, death)
• Hashimoto's encephalopathy (confusion, heat intolerance, dementia)
• Wernicke's encephalopathy (mental confusion,memory loss, decreased ability to move eyes)
• Bovine spongiform encephalopathy (BSE) or "mad cow disease" (ataxia, dementia, and myoclonus or muscle twitching without any rhythm or pattern)
• Shigellaencephalopathy (headache,stiff neck,delirium, seizures, coma)
• Infectious causes of pediatric encephalopathy (irritability, poor feeding, hypotonia or floppy baby syndrome, seizures, death)

The best way to understand potential complications is to discuss these with the diagnosing doctor who can discuss the possible problems associated with the specific cause(s) of the type of encephalopathy.

The prognosis for a patient with encephalopathy depends on the initial causes and, in general, the length of time it takes to reverse, stop, or inhibit those causes. Consequently, the prognosis varies from patient to patient and ranges from complete recovery to a poor prognosis that often leads to permanent brain damage or death.

This highly variable prognosis is exemplified by patients that get encephalopathy from hypoglycemia. If patients with hypoglycemia are given glucose at the first signs of encephalopathy (for example, irritability, mild confusion), most patients recover completely. Delays in correcting hypoglycemia (hours to days) may lead to seizures or coma, which may be halted by treatment with complete or partial recovery (minimal permanent brain damage). A long delay or multiple delays in treatment can lead to a poor prognosis with extensive brain damage, coma, or death.

Although the symptoms and time frame vary widely from patient to patient and according to the initial causes of encephalopathy (see above sections for examples of causes), the prognosis of each case usually follows the pattern described in thehypoglycemicexample above and depends upon the extent and rapidity with which the underlying cause is treated. The doctor or team of doctors treating the underlying cause of encephalopathy can offer the best information on the individual's prognosis.

Many cases of encephalopathy can be prevented. The key topreventionis to stop or limit the chance of developing any of the multitudes of causes of encephalopathy. If encephalopathy develops, the quicker the underlying cause is treated, the more likely that severe encephalopathy can be prevented.

Examples of prevention (and situations to avoid) are listed below:

• Diabetic encephalopathy:Follow your prescribeddiabetes managementplan, including taking glucose measurements when appropriate. Take all medications as directed.
• Hepatic encephalopathy:Avoid alcohol intoxication, drug overdoses, and IV injections of illegal drugs.
• Anoxic encephalopathy:Prevent choking on food. Avoid risky behavior that could lead to head and neck trauma. Avoid exposure to carbon monoxide.
• Hypertensive encephalopathy:Monitor blood pressure; take antihypertensive medication as directed and do not stop medications or change medication without consulting a doctor.
• Infectious encephalopathy:Avoid physical contact with individuals known to be infected with organisms that may cause encephalopathy such asN. meningitidisorShigella.
• Uremic encephalopathy:Do not skip or avoid scheduled dialysis. Take all medications as directed and have frequent assessments of mental status.

Methods for prevention of encephalopathy are about as numerous as the underlying causes; however, some cases of encephalopathy may not be preventable (for example, congenital and accidental traumatic encephalopathy).

• Wernicke Encephalopathy
• Hepatic Encephalopathy
• Hypertensive Encephalopathy
• Mad Cow Disease
• Kidney Failure
• Confusional States and Acute Memory Disorders
• 脑电图在痴呆和脑病