What Causes Obtunded Behavior in Humans?

Obtundation in humansA number of medical disorders can cause a decrease in alertness, sometimes even posing a risk of injury or death. This Buzzle article deals with obtundation, a condition similar to lethargy, and tells you what its causes actually are.
Did You Know?
Statistics reveal that up to 5% of emergency room visits in urban US hospitals are due to disorders related to consciousness.
The term consciousness describes the ability to be alert, and respond to any changes in our surrounding environment. Under normal circumstances, human consciousness can be of two types – wakefulness, which describes the fully alert state that we function in when not asleep, and sleep, in which the mind and body are temporarily inactive, but can be aroused.

Consciousness is governed by two parts of our brain – the cerebrum and brain stem. The cerebrum interacts with the brain stem and keeps us alert, but it can also modify this level of alertness by taking feedback from our sense organs like the eyes, skin, and ears.

When there is an undesirable change in the blood flow to the brain, or the brain suffers an injury, abnormal states of consciousness may be experienced. As opposed to the two states of normal consciousness, there are a number of abnormal states. One of these altered states of consciousness is obtundation.

What Does Obtundation Mean?

Obtundation is a state in which a person’s consciousness level is moderately reduced due to a medical condition or trauma. Such an individual is less aware of his/her surroundings and is unresponsive, but can be awakened by verbal or physical stimulus. The term obtundation is influenced from the Latin word obtundere, which means to dull or blunt, as such patients exhibit dullness.


► Disorientation
► Unresponsiveness
► Unaware of surroundings
► Response to loud verbal and physical stimulus
► Response takes a long time
► Drowsiness and increased sleep periods
► Response to painful stimuli by vocalization, grimacing, and attempts to remove the stimulus
► Changing posture while sleeping
► Attempts to remove intravenous needles and catheters

Difference Between Obtundation, Lethargy, and Stupor

These terms are the different stages of an altered level of consciousness (ALC). This is a condition where an individual is less aware of the external environment as compared to a fully alert individual. The different stages of ALC, from mild to severe, are lethargy, obtundation, stupor, and coma. Thus, lethargy is a slight decrease in consciousness, and a lethargic person can be awakened by a simple verbal stimulus like shouting. Obtundation involves greater, but still a moderate drop in consciousness levels; such people can be temporarily aroused by repeated verbal or physical stimulus like vigorous shaking, but may become unresponsive again. Stupor is a deep state of unresponsiveness, and such individuals may even need a painful stimulus (like pinching) to awaken them. On the other hand, a comatose patient is completely unresponsive, and does not react even to something that is painful.

What Causes Obtundation?

1. Diseases

Diabetes and its complications
Liver/kidney diseases
African trypanosomiasis (sleeping sickness)
Bubonic plague

2. Events

Head injury
Sleep deprivation for long periods

3. Metabolic Disturbances

Very high/low sodium levels
Very high/low blood pH
Low phosphate levels
Increase in level of carbon dioxide in blood
Low oxygen level in blood

4. Blood Circulation/Heart Problems

Severe heart failure
Very low/high blood pressure
Inflammation of blood vessels

5. Problems in Nervous System

Brain cancer
Infections of the brain, like encephalitis
Encephalopathy (diseases that alter brain structure)
Central pontine myelinolysis (damage of nerve cells in brain stem)

6. Substance Abuse

Alcohol intoxication or poisoning
Overdose of opiates, narcotics, seizure medication, and sedatives
Toxins like hydrocarbons or heavy metals

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