What Is Metabolic Encephalopathy?

A high level of ammonia in the blood is a possible indication of metabolic encephalopathy.

Metabolic encephalopathy or toxic metabolic encephalopathy is a condition in which brain function is disturbed either temporarily or permanently due to different diseases or toxins in the body. Metabolic encephalopathies may be reversible if the preexisting disorders are treated. If left untreated, they may result in brain damage. The common signs and symptoms of metabolic encephalopathy include:

• Delirium is considered the most common symptom of metabolic encephalopathy. It is characterized by confused thinking and disrupted attention usually accompanied by disordered speech and hallucinations.
• Dementia (loss of memory)
• Ataxia (difficulty coordinating with motor tasks such as walking, eating, writing, or some daily activities)
• Jaundice
• Decreased consciousness 
• Coma
• Agitation
• Illusions
• Decreased orientation to surroundings 
• Mood disorders 
• Thought and memory disorders 
• Depression 
• Insomnia
• Nausea/Vomiting
• Heart rhythm disorders
• Breathing problems
• Tremors 
• Seizures
• Vision changes

Preexisting health conditions such as diabetes, liver disease, kidney failure, or heart failure, may lead to the accumulation of toxic products in the body. These may cause brain cell swelling and hamper their function. For example, recurrent abnormal sugar levels in the blood may lead to confusion and even a coma. Metabolic encephalopathy causes include:

• Medications
• Illicit drugs
• Toxic chemicals
• Organ failures such as liver, heart, or kidney failure
• Alcohol
• Dehydration
• Electrolyte imbalance
• Severe constant and recurrent fever episodes 
• High blood pressure
• Low oxygen in the blood
• Infections including sepsis
• Thiamine deficiency
• Old age

A high level of ammonia in the blood is a possible indication of metabolic encephalopathy.

• Metabolic encephalopathy is usually diagnosed through blood, urine, and spinal fluid samples.
• Blood tests may also show if there is an infection or if there are drugs or toxins in the blood.
• Computed tomography (CT) or magnetic resonance imaging (MRI) may be used to rule out any brain-related problems.
• An electroencephalogram (EEG) examination may also be done to rule out any abnormalities in the brain.

The treatment of metabolic encephalopathy requires the management of underlying diseases that emerge from the evaluation of neurological symptoms and signs. Early recognition of the preexisting factor may be essential:

• Delirium should be treated as a medical emergency. 
• Monitoring of respiratory and circulatory functions is a priority, with neurological, laboratory, and neuroimaging evaluations. 
• The patient should be usually placed in a placid, stress-free environment and encouraged to engage in cognitive activities.
• An analgesic may be given for pain control. 
• Antipsychotics such as haloperidol may be given in low doses; however, there may be limitations to this drug.
• Drugs such as quetiapine or olanzapine are being used (without FDA approval).
• Benzodiazepines may be used in cases of alcoholism and cocaine withdrawal. 
• As per research, dexmedetomidine, midazolam, or lorazepam reduces the occurrence and episodes of delirium.
• Patients are maintained on a low-protein diet to lower their blood ammonia levels because ammonia is a by-product of protein metabolism.
• Liver transplantation may be considered in patients with chronic liver cirrhosis.

The recovery of patients with metabolic encephalopathy depends on the cause and type of encephalopathy.

• Recovery usually varies among patients, and a poor prognosis could lead to complete loss of brain function or death.
• Prompt diagnosis and intervention are important as exemplified in the management of hypoglycemic patients.
• Patients given glucose at the onset of symptoms recover completely.
• Delayed treatment may lead to seizures or coma, which may be reversed within hours or days with partial recovery. However, long or multiple delays can be fatal.