Altered level of consciousness in the context of "Lethargy"

Diarrhea (American English), also spelled diarrhoea or diarrhœa (British English), is the condition of having at least three loose, liquid, or watery bowel movements in a day. It often lasts for a few days and can result in dehydration due to fluid loss. Signs of dehydration often begin with loss of the normal stretchiness of the skin and irritable behaviour. This can progress to decreased urination, loss of skin color, a fast heart rate, and a decrease in responsiveness as it becomes more severe. Loose but non-watery stools in babies who are exclusively breastfed, however, are normal.

The most common cause is an infection of the intestines due to a virus, bacterium, or parasite—a condition also known as gastroenteritis. These infections are often acquired from food or water that has been contaminated by feces, or directly from another person who is infected. The three types of diarrhea are: short duration watery diarrhea, short duration bloody diarrhea, and persistent diarrhea (lasting more than two weeks, which can be either watery or bloody). The short duration watery diarrhea may be due to cholera, although this is rare in the developed world. If blood is present, it is also known as dysentery. A number of non-infectious causes can result in diarrhea. These include lactose intolerance, irritable bowel syndrome, non-celiac gluten sensitivity, celiac disease, inflammatory bowel disease such as ulcerative colitis, hyperthyroidism, bile acid diarrhea, and a number of medications. In most cases, stool cultures to confirm the exact cause are not required.

A neurological disorder is any disorder of the nervous system. Structural, biochemical or electrical abnormalities in the brain, spinal cord, or other nerves can result in a range of symptoms. Examples of symptoms include paralysis, muscle weakness, poor coordination, loss of sensation, seizures, confusion, pain, tauopathies, and altered levels of consciousness. There are many recognized neurological disorders; some are relatively common, but many are rare.

Interventions for neurological disorders include preventive measures, lifestyle changes, physiotherapy or other therapy, neurorehabilitation, pain management, medication, operations performed by neurosurgeons, or a specific diet. The World Health Organization estimated in 2006 that neurological disorders and their sequelae (direct consequences) affect as many as one billion people worldwide and identified health inequalities and social stigma/discrimination as major factors contributing to the associated disability and their impact.

Lethargy is a state of tiredness, sleepiness, weariness, fatigue, sluggishness, or lack of energy. It can be accompanied by depression, decreased motivation, or apathy. Lethargy can be a normal response to inadequate sleep, overexertion, overworking, stress, lack of exercise, improper nutrition, drug abuse, boredom, or a symptom of an underlying illness or disorder. It may also be a side effect of medication or caused by an interaction between medications and alcohol. It may also be an altered level of consciousness.

When part of a normal response, lethargy often resolves with rest, adequate sleep, decreased stress, physical exercise, and good nutrition. Its symptoms, however, can last days or even months, so it can be a sign of a recent underlying illness or infection if it does not resolve normally.

Hyponatremia or hyponatraemia is a low concentration of sodium in the blood. It is generally defined as a sodium concentration of less than 135 mmol/L (135 mEq/L), with severe hyponatremia being below 120 mEq/L. Symptoms can be absent, mild or severe. Mild symptoms include a decreased ability to think, headaches, nausea, and poor balance. Severe symptoms include confusion, seizures, and coma; death can ensue.

The causes of hyponatremia are typically classified by a person's body fluid status into low volume, normal volume, or high volume. Low volume hyponatremia can occur from diarrhea, vomiting, diuretics, and sweating. Normal volume hyponatremia is divided into cases with dilute urine and concentrated urine. Cases in which the urine is dilute include adrenal insufficiency, hypothyroidism, and drinking too much water or too much beer. Cases in which the urine is concentrated include syndrome of inappropriate antidiuretic hormone secretion (SIADH). High volume hyponatremia can occur from heart failure, liver failure, and kidney failure. Conditions that can lead to falsely low sodium measurements include high blood protein levels such as in multiple myeloma, high blood fat levels, and high blood sugar.

Methanol toxicity (also methanol poisoning) is poisoning from methanol, characteristically via ingestion. Symptoms may include an altered/decreased level of consciousness, poor or no coordination, vomiting, abdominal pain, and a specific smell on the breath. Decreased vision may start as early as twelve hours after exposure. Long-term outcomes may include blindness and kidney failure. Ingestion of as little as 3.16 grams of methanol can cause irreversible optic nerve damage, and the oral LD50 for humans is estimated to be 56.2 grams.

Methanol poisoning most commonly occurs following the drinking of windshield washer fluid. This may be accidental or as part of an attempted suicide. Toxicity may also rarely occur through extensive skin exposure or breathing in fumes. When the body breaks down methanol it results in the creation of metabolite byproducts such as formaldehyde, formic acid, and formate which cause much of the toxicity. The diagnosis may be suspected when there is acidosis or an increased osmol gap and confirmed by directly measuring blood levels. Other conditions that can produce similar symptoms include infections, exposure to other toxic alcohols, serotonin syndrome, and diabetic ketoacidosis.

Alertness is a state of active attention characterized by high sensory awareness. Someone who is alert is vigilant and promptly meets danger or emergency, or is quick to perceive and act. Alertness is a psychological and physiological state.

Lack of alertness is a symptom of a number of conditions, including narcolepsy, attention deficit hyperactivity disorder, chronic fatigue syndrome, depression, Addison's disease, and sleep deprivation. Pronounced lack of alertness is an altered level of consciousness. States with low levels of alertness include drowsiness.

Obtundation is mild to moderate alertness reduction (altered level of consciousness) with decreased interest in the environment and slower than normal reactivity to stimulation. It is distinguished from the much stronger states of unresponsiveness of stupor and coma. Obtundation typically occurs as a result of a medical condition or trauma.

There is a wide range of potential causes including head injury, interruption of blood circulation, impaired oxygenation or carbon dioxide toxicity (hypercapnia); central nervous system (CNS) infections, drug intoxication or withdrawal, post-seizure state, hypothermia, and metabolic derangements such as hypoglycemia, hyponatremia, and hypercalcaemic crisis.

Hepatic encephalopathy (HE) is an altered level of consciousness as a result of liver failure. Its onset may be gradual or sudden. Other symptoms may include movement problems, changes in mood, or changes in personality. In the advanced stages, it can result in a coma.

Hepatic encephalopathy can occur in those with acute or chronic liver disease. Episodes can be triggered by alcoholism, infections, gastrointestinal bleeding, constipation, electrolyte problems, or certain medications. The underlying mechanism is believed to involve the buildup of ammonia in the blood, a substance that is normally removed by the liver. The diagnosis is typically based on symptoms after ruling out other potential causes. It may be supported by blood ammonia levels, an electroencephalogram, or computer tomography (CT scan) of the brain.