The lower part of the human brain that connects the brain to the spinal cord, is called the brain stem. Although the brain stem is small in size, it plays a key role in the functioning of our body. It serves as a connector between the brain and other organs of our body, and is made up of three parts: midbrain, medulla oblongata and pons. As the brain stem regulates many of the vital functions of our body, any injury to it can be life-threatening.
The Brain Stem and its Functions
All the three parts of the brain stem have special functions to perform, that together contribute to its overall functioning. To have a better understanding of the consequences of brain stem injury, let us first learn about the functions of the three parts of the brain stem.
The midbrain, as the name suggests, is located at the center of the brain, below the cerebral cortex. The following are the functions of the midbrain.
- Controls the visual and auditory systems
- Controls the movement of eye muscles
- Controls the movement of voluntary muscles
- Releases dopamine, a neurotransmitter, which plays an important role in motor and cognition functioning
- Controls the respiratory muscles
- Regulates autonomic functions and awareness
- Regulates body temperature
The medulla oblongata is located in the lower half of the brain stem, and performs the following functions:
- Cardiovascular center regulates heartbeat
- Respiratory center controls the movement of respiratory muscles, including the diaphragm, and regulates the rate of respiration
- Vasomotor center regulates blood pressure
- Reflex centers regulate reflex actions, like sneezing, coughing, swallowing, etc
The pons is a part of the brain stem that is located between the midbrain and the medulla oblongata. Its functions are as follows:
- Controls autonomic functions
- Conducts signals from the cerebrum to the cerebellum and medulla oblongata
- Regulates sleep patterns
- Controls arousal functions like waking up or being alert
Causes of Brain Stem Injury
The brain is a mass of soft tissue that is enclosed within the skull, and is protected by the surrounding cerebrospinal fluid that acts as a shock absorber. Injury to the brain stem can lead to permanent damage, since it regulates almost all the daily activities of our body. Any damage to the brain can be directly related to an injury to the brain stem and hence, the symptoms are similar. Brain injury involves damage to the nerve cells and/or the blood vessels surrounding the brain. Given below are the common causes of brain stem injury.
» A heavy blow on the head can result in the brain twisting on its axis, which can damage the nerve pathways that are the transmission channels for neural impulses and signals. Also, there are chances of the brain hitting against the bones of the skull, causing further damage to the nerve tissues.
» When there is a swelling in any part of the brain stem, it increases the pressure inside the skull. This leads to compression of the brain stem, which may further lead to complications.
» Brain stem injury, or injury to any other part of the brain, can also be a result of infection, tumors, or neurotoxins.
» However, most cases of severe brain injury are a result of trauma caused by motor accidents, falls, gunshots, explosives, injuries incurred during sports, etc. Brain stem injury caused by trauma or a forceful impact on the brain, is termed as traumatic brain injury. Depending on whether the skull is fractured or not, traumatic brain injuries can either be closed head injuries or penetrating injuries. Closed head injuries can be fatal as they cause bleeding inside the skull due to the rupture of blood vessels (intracranial hematoma), concussion (dysfunctioning of the brain), and diffuse axonal injury (injury to the axons).
Signs and Symptoms
The symptoms of brain stem injury can range from mild symptoms to severe ones, and can even prove lethal. Here, we shall learn about the symptoms observed in patients with mild to severe brain stem injuries.
- Loss of consciousness
- Prolonged headache
- Dysphagia or difficulty in swallowing food and water
- Momentary loss of memory
- Reduced levels of concentration
- Sleep apnea and insomnia
- Difficulty in breathing
- Blurred vision
- Depression and anxiety
- Mood swings
- Prolonged loss of consciousness (for several hours)
- Unusual behavior
- Partial/complete loss of memory
- Cognitive dysfunction
- Slurred speech
- Confused state of mind
- Impaired muscle coordination
- Severe persistent headache
- Dilation of pupils
- Nausea and vomiting
- Change in sleep patterns
- Loss of appetite
- Severe depression
- Cardiac arrest
Diagnosis and Treatment
The diagnosis is carried out to detect fractures in the bones of the skull, neck, and spine, by imaging tests such as Computerized Tomography (CT) scan or Magnetic Resonance Imaging (MRI). For the diagnosis of closed head injury, the pressure within the skull (intracranial pressure) is measured with a device known as intracranial pressure monitor.
The injured should receive immediate medical attention to prevent further injury. This is because, damage to brain tissue is irreversible. For a patient with severe head injury, it is important to ensure supply of sufficient oxygen to the brain in order to prevent the death of brain cells. Also, it is vital to monitor the blood pressure, and take adequate measures to keep it stable. For patients with severe injuries, the treatment comprises medications and surgery, if needed. Sometimes, surgery is recommended to relieve the pressure build-up inside the skull. Also, surgery is essential to repair fractures in the skull.
Rehabilitation and Recovery
For patients who have experienced severe brain injuries, rehabilitation is essential to resume a normal life. Depending on the severity of the injury that the patient has suffered from, the rehabilitation therapy generally comprises the following elements:
- Speech therapy: It assists the patient in relearning/improving his communication skills.
- Physiotherapy: It helps the patient stand on his feet, and to learn to walk again.
- Occupational therapy: It helps the patient improve his ability to perform day-to-day activities.
- Recreational therapy: It helps the patient learn the required skills to take up a hobby that can help him enjoy his leisure time.
- Counseling: The counselor listens to the difficulties faced by the patient, and motivates him/her for continuing with the rehabilitation program.
Severe injury to the lower part of the brain, including the brain stem, can cause locked-in syndrome in the patient. This means that the patient is in an altered state of consciousness, where he is aware of his surroundings, but cannot speak or move his body. However, he is able to blink his eyes, and this is how he gradually learns to communicate and respond to his surroundings. There are a few other possible complications that can be a result of injury to the brain stem, and these are given as under.
- Damage to blood vessels, causing blood clots and stroke
- Paralysis of the muscles of the neck and face
- Blindness/double vision
- Loss of hearing ability
- Degenerative brain diseases
Brain stem injury is a very serious health condition that can alter one's life. However, proper medical aid at the right time can prove to be beneficial.
Disclaimer: The information provided in this article is solely for educating the reader. It is not intended to be a substitute for the advice of a medical expert.