What is the difference between comatose and catatonic

Toxic substances may be taken into the body for example, by consuming or inhaling them. Or they may be produced in the body as a waste product of normal processes but are not broken down and removed as they normally are.

The brain consists of the cerebrum, brain stem, and cerebellum. Each half hemisphere of the cerebrum is divided into lobes. Periods of impaired consciousness can be short or long. The degree of impairment can range from slight to severe.

Doctors use various terms to describe the different levels of consciousness:. Lethargy is a slight reduction in alertness or mild mental fogginess clouding of consciousness. People tend to be less aware of what is happening around them and to think more slowly than usual. They may appear tired. Obtundation, an imprecise term, refers to a moderate reduction in alertness or moderate clouding of consciousness. Delirium Delirium Delirium is a sudden, fluctuating, and usually reversible disturbance of mental function.

It is characterized by an inability to pay attention, disorientation, an inability to think clearly People cannot pay attention or think clearly. They are disoriented and may not know where they are or what time it is.

They may be overly alert, attentive, and able to think clearly one moment and be sluggish, distracted, and confused the next. Altered mental status, a very imprecise term, is sometimes used by doctors to refer to a change in consciousness, such as lethargy, obtundation, delirium, or sometimes stupor or coma. Stupor is an excessively long or deep state of unresponsiveness. People can be aroused from it only briefly by vigorous stimulation, such as repeated shaking, loud calling, or pinching.

Coma is a state of complete unresponsiveness except for certain automatic reflexes. People cannot be aroused at all. Their eyes stay closed. People in a deep coma lack purposeful responses, such as moving a limb away from something that hurts. The various levels of impaired consciousness—lethargy, obtundation, stupor, and coma—have the same causes, of which there are many. A toxic substance, such as carbon monoxide Carbon Monoxide Poisoning Carbon monoxide poisoning is common.

Symptoms may include headache, nausea, drowsiness, and confusion. The diagnosis is based on blood tests. Carbon monoxide detectors, adequate venting of furnaces A drug, such as alcohol Alcohol Alcohol ethanol is a depressant. Consuming large amounts rapidly or regularly can cause health problems, including organ damage, coma, and death. Genetics and personal characteristics may Opioids are used to relieve pain, but they Using prescription A metabolic abnormality, such a very low blood sugar level hypoglycemia Hypoglycemia Hypoglycemia is abnormally low levels of sugar glucose in the blood.

Hypoglycemia is most often caused by drugs taken to control diabetes. Much less common causes of hypoglycemia include other Urination and thirst are A disorder that makes nerve cells in the brain malfunction and communicate less well, such as liver failure Liver Failure Liver failure is severe deterioration in liver function.

Liver failure is caused by a disorder or substance that damages the liver. Most people have jaundice yellow skin and eyes , feel tired Kidney failure is the inability of the kidneys to adequately filter metabolic waste products from the blood.

A severe infection in or around the brain, such as meningitis Introduction to Meningitis Meningitis is inflammation of the layers of tissue that cover the brain and spinal cord meninges and of the fluid-filled space between the meninges subarachnoid space. Meningitis can be An abscess may form in the brain when bacteria from an infection elsewhere in the head or in the bloodstream or from a wound enter the brain A severe infection elsewhere in the body, such as sepsis Sepsis and Septic Shock Sepsis is a serious bodywide response to bacteremia or another infection plus malfunction or failure of an essential system in the body.

Septic shock is life-threatening low blood pressure Severe or prolonged seizures Seizure Disorders In seizure disorders, the brain's electrical activity is periodically disturbed, resulting in some degree of temporary brain dysfunction. Many people have unusual sensations just before a seizure Inadequate blood flow to the brain, as occurs when the heart stops cardiac arrest Cardiac Arrest and CPR Cardiac arrest is when the heart stops pumping blood and oxygen to the brain and other organs and tissues.

Sometimes a person can be revived after cardiac arrest, particularly if treatment is Head injuries Overview of Head Injuries Head injuries that involve the brain are particularly concerning. Common causes of head injuries include falls, motor vehicle crashes, assaults, and mishaps during sports and recreational activities A concussion may involve a loss of consciousness, can occur without obvious damage to brain structures Disorders that increase pressure within the skull intracranial pressure , including certain brain tumors Overview of Brain Tumors A brain tumor can be a noncancerous benign or cancerous malignant growth in the brain.

It may originate in the brain or have spread metastasized to the brain from another part of the body Examples are. A very low level of oxygen in the blood, as occurs in respiratory lung failure Respiratory Failure Respiratory failure is a condition in which the level of oxygen in the blood becomes dangerously low or the level of carbon dioxide in the blood becomes dangerously high.

Conditions that block Blood delivers oxygen and essential nutrients such as fats, sugars, minerals, and vitamins to the body's tissues. Thus, when blood flow to the brain is decreased, the brain is deprived of oxygen and essential nutrients. The brain may also be deprived of oxygen when the lungs are not functioning normally, as occurs in respiratory failure.

The brain can be deprived of nutrients when a disorder such as hypoglycemia causes levels of nutrients in the blood to be low. Having diabetes Diabetes Mellitus DM Diabetes mellitus is a disorder in which the body does not produce enough or respond normally to insulin, causing blood sugar glucose levels to be abnormally high.

When blood sugar levels are very high, people become dehydrated Dehydration Dehydration is a deficiency of water in the body. Vomiting, diarrhea, excessive sweating, burns, kidney failure, and use of diuretics may cause dehydration.

People feel thirsty, and as dehydration When blood sugar levels are low, the brain is deprived of its main source of energy sugar and can malfunction or become damaged.

Over time, diabetes damages the blood vessels and nerve cells in the brain. As a result, the brain may not get enough oxygen, and brain tissue may die. Other disorders can cause cells throughout the body to malfunction. Often, brain cells are affected the most. These disorders include. Liver failure Liver Failure Liver failure is severe deterioration in liver function.

An underactive thyroid gland hypothyroidism Hypothyroidism Hypothyroidism is underactivity of the thyroid gland that leads to inadequate production of thyroid hormones and a slowing of vital body functions. Facial expressions become dull, the voice A very low or high body temperature hypothermia Hypothermia Hypothermia is a dangerously low body temperature.

Hypothermia is often regarded as a cold injury, because it can be caused or made worse by exposure to cold surroundings. Being in an environment See also Overview of Heat Disorders. Heatstroke can develop after Very low or high levels of calcium Overview of Calcium's Role in the Body Calcium is one of the body's electrolytes, which are minerals that carry an electric charge when dissolved in body fluids such as blood, but most of the body's calcium is uncharged.

See also Electrolytes carry an electric charge when dissolved in body fluids such as blood Thiamin deficiency Thiamin Deficiency Thiamin deficiency causing beriberi and other problems is most common among people whose diet mainly consists of white rice or highly processed carbohydrates in developing countries and among Other common causes are disorders that affect the areas of the brain that control consciousness.

These disorders include the following:. A head injury Overview of Head Injuries Head injuries that involve the brain are particularly concerning.

Strokes Complications of stroke A stroke occurs when an artery to the brain becomes blocked or ruptures, resulting in death of an area of brain tissue due to loss of its blood supply cerebral infarction and symptoms that Any disorder that increases pressure within the skull intracranial pressure can impair consciousness.

A mass in the brain, such as an accumulation of blood hematoma , a tumor, or an abscess, can impair consciousness indirectly by putting pressure on the areas of the brain that control consciousness. A structural abnormality, which may be present at birth, can block the flow of cerebrospinal fluid in the brain, increasing pressure within the skull. Cerebrospinal fluid is the fluid that flows through the tissues covering the brain and spinal cord and fills the spaces within the brain.

A large mass can push the brain against the relatively rigid structures inside the skull, damaging brain tissue. If the areas of the brain that control consciousness are affected, stupor or coma results. If the pressure is high enough, the brain may be forced through a small natural opening in the relatively rigid sheets of tissue that separate the brain into compartments. This life-threatening disorder is called brain herniation Herniation: The Brain Under Pressure Head injuries that involve the brain are particularly concerning.

Herniation can further damage brain tissue, making an already dire condition worse. Having had a stroke or having another disorder that affects brain function makes the brain more susceptible to other disorders that can impair consciousness. Commonly, consciousness is impaired by drinking too much alcohol Alcohol Alcohol ethanol is a depressant. For example, setting a broken bone in a cast or giving antibiotics for an infected joint helps reduce pain In addition to making brain cells function slowly, alcohol and some drugs can damage brain cells indirectly.

They can slow breathing so much that the oxygen level in blood becomes low enough to cause brain damage. Taking several drugs to treat several disorders is also a common cause, partly because taking several drugs increases the risk of interactions between drugs. Overdoses of marijuana Marijuana Marijuana cannabis is a drug made from the plants Cannabis sativa and Cannabis indica that contain a psychoactive chemical called deltatetrahydrocannabinol THC.

Marijuana produces a dreamy Occasionally, taking certain antipsychotic drugs Antipsychotic drugs Schizophrenia is a mental disorder characterized by loss of contact with reality psychosis , hallucinations usually, hearing voices , firmly held false beliefs delusions , abnormal thinking This syndrome is characterized by muscle rigidity, fever, and high blood pressure, as well as changes in mental function such as confusion and lethargy.

Occasionally, people who have a psychiatric disorder or those who are psychologically stressed may appear unresponsive. For example, people who learn that they have cancer or that their spouse is going to leave them may collapse and not respond when they are spoken to or touched.

Yet, such people may be aware of what is happening around them, and their brain may be functioning normally. Based on the results of the examination Diagnosis Stupor is unresponsiveness from which a person can be aroused only by vigorous, physical stimulation. Coma is unresponsiveness from which a person cannot be aroused and in which the person's Aging alone does not increase the risk of impaired consciousness.

However, age-related changes make impaired consciousness in older people a particular concern see Essentials for Older People: Stupor and Coma Essentials for Older People: Coma and Stupor Stupor is unresponsiveness from which a person can be aroused only by vigorous, physical stimulation.

For example, some disorders that are more common among older people such as high blood pressure or diabetes can increase the risk of impaired consciousness if another problem develops. Dehydration Dehydration Dehydration is a deficiency of water in the body. Development of a new disorder such as stroke or heart failure or worsening of a disorder they already have. Consciousness is impaired to varying degrees. People in a stupor are usually unconscious but can be aroused with vigorous stimulation.

People in a coma are unconscious, with their eyes closed, and they cannot be aroused. The pattern of breathing is usually abnormal. People may breathe too rapidly, too slowly, too deeply, or irregularly.

Or they may alternate between these abnormal patterns. Blood pressure may increase or decrease, depending on the cause of the impaired consciousness. For example, if a head injury causes massive bleeding in the brain, pressure within the skull rapidly increases, and blood flow to the brain decreases.

The nerves that control blood pressure respond by increasing blood pressure to try to maintain normal blood flow to the brain. If the cause of impaired consciousness is a severe infection, severe dehydration, major blood loss, drug overdose, or cardiac arrest, blood pressure decreases dramatically. Muscles may contract and remain contracted in unusual positions. For example, the head may be tilted back with the arms and legs extended—a position called decerebrate rigidity.

Or the arms may be flexed with both legs extended—a position called decorticate rigidity. Or the entire body may be limp.

Sometimes muscles contract sporadically or involuntarily. The eyes may be affected. One or both pupils of the eyes may be widened dilated and may not react to changes in light. Or the pupils may be tiny. The eyes may not move or may move in abnormal ways.

The disorder that is impairing consciousness may cause other symptoms. For example, if the cause is meningitis infection of the layers of tissue covering the brain and spinal cord , early symptoms may include fever, vomiting, headache, and a painful, stiff neck that makes lowering the chin to the chest difficult or impossible.

Being unable to move immobilization for a long time, as occurs in coma, can also cause problems, such as pressure sores, nerve damage in the limbs, blood clots, and urinary tract infections see Problems Due to Bed Rest Problems Due to Bed Rest Staying in bed for a long time without regular physical activity, as may occur in a hospital, can cause many problems.

See also Problems Due to Hospitalization. A leg injury, leg surgery, Doctors can tell that consciousness is impaired based on observation and examination. Doctors try to identify the parts of the brain that are impaired and the cause of impairment because treatment differs and because impairment may progress, leading to coma and brain death.

Stupor is diagnosed when vigorous, repeated attempts arouse the person only briefly. Coma is diagnosed when the person cannot be aroused at all and the eyes remain closed. People who become stuporous or comatose must be taken to the hospital immediately because either state may be caused by a life-threatening disorder.

Health care practitioners try to identify the cause and provide emergency medical care at the same time. For example, a quick test is done to estimate the blood sugar level.

Then if people have a low blood sugar level which can quickly and permanently damage the brain , it can be treated immediately. A stuporous or comatose person cannot communicate. So the doctor usually checks whether the person is wearing a medical alert identification bracelet or necklace, which may suggest the cause. The doctor may check the person's wallet, purse, or pockets for medical identification such as a hospital identification card or drugs, which may also help identify the cause.

Thus, a person with a disorder that increases the risk of stupor or coma such as diabetes or a seizure disorder should carry or wear some form of medical identification. The doctor asks any witnesses of the change in consciousness about the circumstances in which it occurred and any other symptoms the person had. For example, if the person's limbs jerked repeatedly when consciousness was affected, the cause may have been a seizure. The doctor also talks to family members and friends, who should honestly provide emergency medical personnel or the doctor with any relevant information about the person, which includes the following:.

Whether the person uses drugs prescription and recreational , alcohol, or other toxic substances and which ones are used. Whether the person has or has had any infections, other disorders such as diabetes, high blood pressure, a seizure, or a thyroid, kidney, or liver disorder , or other symptoms such as headaches or vomiting.

Whether they have any hunches about what might be the cause for example, if the person was recently depressed or talked about suicide. This information can help doctors identify possible causes and helps them assess how likely the person is to recover. Many such causes would not be identified, even with extensive diagnostic testing, if this information was unavailable. For example, if people have eaten unusual foods, the cause may be a toxin such as those in poison mushrooms.

If people have traveled recently, the cause may be an infection that is common in the area they visited. If empty pill containers or drug paraphernalia were found nearby, the cause may be a drug overdose. If a drug or toxic substance was ingested, family members or friends should give a sample of that substance or its container to the doctor.

Information from friends and family members is often more helpful in determining the cause of coma than diagnostic tests. Information from the family and friends is usually valuable and is more likely to lead to the correct diagnosis than examination or testing.

For example, no test can rule out all possible drug overdoses. Body temperature is checked. An abnormally high temperature may indicate infection, heatstroke, or an overdose of a drug that stimulates the body such as cocaine or an amphetamine. An abnormally low temperature may indicate prolonged exposure to cold, an underactive thyroid gland, alcohol intoxication, a sedative overdose or, in older people, infection.

Black eyes, cuts, bruises, or leakage of cerebrospinal fluid the fluid that surrounds the brain from the nose or ears suggests a head injury.

Fever with a rash often suggests an infection, such as sepsis a serious bodywide response to a bloodstream infection or a brain infection. Certain odors on the breath suggest diabetic ketoacidosis Diabetic Ketoacidosis Diabetic ketoacidosis is an acute complication of diabetes that occurs mostly in type 1 diabetes mellitus.

Symptoms of diabetic ketoacidosis include nausea, vomiting, abdominal pain, and a characteristic A thorough neurologic examination Neurologic Examination When a neurologic disorder is suspected, doctors usually evaluate all of the body systems during the physical examination, but they focus on the nervous system. Examination of the nervous system—the This examination helps doctors determine. If people are unconscious, doctors try to rouse them first by speaking to them, then by touching their limbs, chest, or back.

If these measure do not work, doctors use stimuli that cause discomfort or pain, such as pressure on a nail bed or a pinch. If people open their eyes or grimace when a painful stimulus is applied or if they purposefully withdraw from it, consciousness is not severely impaired. If people can make sounds, the cerebral hemispheres are functioning to some degree. If the eyes open, some parts of the brain stem are probably functioning.

Doctors sometimes use a standardized scoring system, such as the Glasgow Coma Scale, to help track changes in a person's level of consciousness. This scale assigns points based on responses to stimuli. Eye movement, speech, and movements are evaluated. This scale is a relatively reliable, objective measure of how unresponsive people are. Abnormal breathing patterns can provide clues to which parts of the brain are malfunctioning.

Checking responses to painful stimulation can help determine whether parts of the brain and spinal cord are malfunctioning. When coma is present, using painful stimuli may trigger unusual body positions. For example, the head may be tilted back with the arms and legs extended called decerebrate rigidity. Or the arms may be flexed with both legs extended called decorticate rigidity. This test helps identify the area of the brain that is not functioning normally. Limpness of the entire body and no movements in response to pain are the worst possible response.

They indicate severe dysfunction in the central nervous system brain and spinal cord. However, if muscle tone and movements return, the cause may be a reversible one, such as a sedative overdose.

Automatic reflexes Reflexes When a neurologic disorder is suspected, doctors usually evaluate all of the body systems during the physical examination, but they focus on the nervous system.

Doctors check for differences in the strength of reflexes in different parts of the body. This information sometimes helps them identify which areas of the brain are not functioning normally. All automatic reflexes are normal if unresponsiveness is caused by a psychiatric disorder that does not impair consciousness.

The eyes also provide important clues about how well the brain stem is functioning and what may be impairing consciousness. Doctors check the position of the pupils, their size, their reaction to bright light, their ability to follow a moving object in people who are alert and awake , and the appearance of the retina.

Normally, pupils widen dilate when light is dim and become smaller constrict when light is shined on them. However, the pupils may not respond normally to light in people in a coma.

How the pupils respond to light or whether they respond helps doctors determine the cause of the coma. Doctors also examine the inside of the eye with an ophthalmoscope Ophthalmoscopy A person who has eye symptoms should be checked by a doctor.

However, some eye disorders cause few or no symptoms in their early stages, so the eyes should be checked regularly every 1 to If findings suggest that the pressure within the skull is increased, doctors do imaging tests immediately to check for swelling, bleeding, a structural abnormality that blocks the flow of cerebrospinal fluid, or a mass in the brain such as a tumor, an accumulation of blood, or an abscess. If test results indicate increased pressure, doctors may drill a small hole in the skull and insert a device into one of the fluid-filled spaces ventricles in the brain.

This device is used to reduce the pressure and monitor it during treatment. If the person is unconscious, gently flushing ice-cold water into one ear, then the other ear and observing eye movements called caloric testing. Caloric testing is done only if people are unconscious and doctors cannot check eye movements any other way. If people are conscious, flushing ice-cold water into their ear can cause severe vertigo Dizziness and Vertigo Dizziness is an inexact term people often use to describe various related sensations, including Faintness feeling about to pass out Light-headedness Dysequilibrium feeling off balance or Blood levels of substances including sugar, electrolytes such as sodium , alcohol, oxygen, minerals such as magnesium , and carbon dioxide are measured.

The result is that someone will be sleepy when awake and may sleep through a great deal of the day. Although people in a coma may appear to be sleeping, real sleep is actually quite different. For example, while sleeping, you are able to turn over or move your arm.

Comatose patients cannot do this. Lesions such as a stroke in certain parts of the brain, including the anterior cingulate gyrus, result in someone who appears to be alert but does not understand what is going on around them and does not move spontaneously. Advanced stages of dementia result in akinetic mutism. Abulia is a kind of extreme lack of incentive due to damage to the pathways that are responsible for motivation.

The result is a person who does not and cannot do much of anything. The degree of abulia can vary, but in extreme cases the person will not move, speak or even eat or drink, thereby resembling akinetic mutism. In less severe cases, an abulic person can be coaxed to follow simple commands, though they will not do this without encouragement. Catatonia is a psychiatric disorder in which a person appears unresponsive but has an otherwise normal neurological exam.

People with catatonia may demonstrate unusual behavior, such as catalepsy, which is keeping seemingly uncomfortable limb positions for a prolonged amount of time. Also, people with catatonia can have repetitive motions that appear similar to a seizure, even though their electroencephalograph EEG is normal. Catatonia may result from psychiatric disorders such as bipolar disorder or schizophrenia.

Technically, locked-in syndrome is not an impairment of consciousness, although it can mimic one. A person who is locked in is unable to move or communicate with the outside world but remains perfectly awake and alert.

For instance, a stroke in the brainstem can cause nearly entire body paralysis and may cause the patient to appear comatose. Depending on the cause, the person may be able to communicate with eye movements. While it may be difficult, every effort must be made to distinguish a comatose or vegetative patient from one who is locked in. How well a patient does with any of these conditions depends on many factors, not the least of which is a correct diagnosis.

Neurologists must take care to correctly diagnose these conditions, as each is caused by different underlying diseases and may respond to different treatments. Sign up for our Health Tip of the Day newsletter, and receive daily tips that will help you live your healthiest life.

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Read our editorial process to learn more about how we fact-check and keep our content accurate, reliable, and trustworthy. Hal Blumenfeld, Neuroanatomy through Clinical Cases. Sunderland: Sinauer Associates Publishers Jerome B. Posner and Fred Plum. Plum and Posner's Diagnosis of Stupor and Coma.

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