Consequences of a Traumatic Brain Injury

In addition to short-term problems (pain, confusion, vision disturbance), TBI is a risk factor for later development of neurodegenerative diseases such as Alzheimer's disease, Parkinson's disease, and amyotrophic lateral sclerosis (ALS). Even mild brain injuries and concussions, especially if they are repeated, are suspected to lead chronic traumatic encephalopathy (CTE).

How are Complications From a TBI Treated?

Postconcussion Syndrome

Within days to weeks of a head injury approximately 40 percent of TBI survivors develop troubling symptoms called post-concussion syndrome (PCS). A person need not have suffered a concussion or loss of consciousness to develop the syndrome and many people with mild TBI suffer from PCS. Symptoms include headache, dizziness, vertigo (a sensation of spinning around or of objects spinning around the person), memory problems, trouble concentrating, sleeping problems, restlessness, irritability, apathy, depression, and anxiety. These symptoms may last for a few weeks after the head injury. The syndrome is more common in individuals who had psychological symptoms, such as depression or anxiety, before the injury. Treatment for PCS may include medicines for pain and psychological conditions, and counseling to develop coping skills.


About 25 percent of patients with brain contusions or hematomas and about 50 percent of patients with penetrating head injuries develop seizures within the first 24 hours of the injury. These seizures generally stop within a week. Doctors typically only treat these seizures if they continue beyond a week. Seizures occurring more than one week after injury are referred to as post-traumatic epilepsy and are treated with medications. The medications may need to be taken by the survivor for months or years following the injury.

(Note: Brain contusions occur when the head is slammed hard against something. The head injury can create a hematoma or subdural hematoma. A hematoma is the swelling of fluid (blood) in the brain and a subdural hematoma is bleeding between the inner and outer sheath of the skull. Head trauma may affect other parts of the body for a short time or permanently.)


Our brains continually produce and drain a fluid called cerebrospinal fluid (CSF). When the brain is injured the drainage of CSF may be blocked causing a build-up. This condition is called hydrocephalus. The build-up of fluid can lead to increased pressure in the brain. Hydrocephalus may begin during the early stages of TBI but not be apparent until much later. However, it usually is diagnosed within the first year after the injury. Symptoms can include a decreased level of consciousness, changes in behavior, lack of coordination or balance, and loss of the ability to hold urine. Treatment may include draining CSF through a small plastic tube called a shunt. The shunt typically runs under the skin from the head to the abdomen, where the fluid drains and is reabsorbed by the body.

Leakage of CSF

Skull fractures can tear the membranes that cover the brain, leading to leakage of CSF. While the leaking fluid may be trapped between the membranes that surround the brain, it may also leak out of the nose or ears. Surgery may be necessary to repair the fracture and stop the leakage.


Tears that let CSF out of the brain cavity can also allow air and bacteria into the cavity. An infection of the membrane around the brain is called meningitis and is a dangerous complication of TBI. Most infections develop within a few weeks of the initial trauma and result from skull fractures or penetrating injuries. Standard treatment includes antibiotics and sometimes surgery to remove the infected tissue.

Damaged Blood Vessels in the Brain

Any injury to the head or brain usually results in some damage to blood vessels in the brain. While the body usually quickly repairs damage to small blood vessels, an injury to larger vessels can result in serious complications. Damage to a major artery supplying blood to the brain can cause a stroke in one of two ways: 1) bleeding from an artery (called a hemorrhagic stroke), or 2) a blood clot that forms in an injured artery. When a clot forms in a major artery it can block blood flow, depriving the area that the artery supplies with blood of needed oxygen and nutrients (known as an ischemic stroke). Symptoms of a blood clot in the head include headache, vomiting, seizures, paralysis on one side of the body, and semi-consciousness.

Surgery is necessary to repair an injured blood vessel that causes a hemorrhagic stroke. Ischemic strokes can be treated with a drug that dissolves clots (a thrombolytic drug) if the stroke is diagnosed within a few hours of the beginning of symptoms and there is no evidence of bleeding in the brain. The drug can be given intravenously or through a tube (catheter) that is inserted into an artery in the groin and then advanced to the brain and then into the clogged artery, where the medication is administered through the catheter. Administering the drug through a catheter at the site of the clot yields has a higher chance of success than giving it intravenously. The catheter method is usually performed only at stroke centers by a team of specialists.

Cranial Nerve Injuries

Cranial nerves run from the brain through openings in the skull and to areas in the head such as the eyes, ears, and face. Skull fractures, especially at the base of the skull, can injure cranial nerves. The seventh cranial nerve, called the facial nerve, is the most commonly injured cranial nerve in TBI. An injured facial nerve can result in paralysis of facial muscles. When facial muscles are paralyzed, facial expressions such as smiling will not be symmetrical. Nerve injuries may heal spontaneously. If they do not, surgery may, in certain circumstances, be able to restore nerve function.


Pain is a common symptom of TBI and can be a significant complication for conscious patients in the period immediately following a TBI. Headache is the most common type of pain, but other kinds of pain can also occur.

Complications for Unconscious Patients

Patients who are unconscious, in a coma, or in a vegetative state can get bed or pressure sores of the skin, repeated bladder infections, pneumonia or other life-threatening infections, and the failure of multiple organs, such as the kidneys, lungs, and heart.

General Trauma

When a TBI occurs there is usually trauma to not only the brain but other parts of the body as well. Care of these injuries can complicate treatment of and recovery from the TBI.

What Disabilities Can Result From a TBI?

Disabilities resulting from a TBI depend upon the severity of the injury, the location of the injury, and the age and general health of the individual.

Cognitive Disabilities

“Cognition” describes the processes of thinking, reasoning, problem solving, information processing, and memory. Most patients with severe TBI, if they recover consciousness, suffer some cognitive disability. People with moderate to severe TBI have more problems with cognitive deficits than survivors with mild TBI, but a history of several mild TBIs (for example, a football player) may have a cumulative effect. Recovery from cognitive deficits is greatest within the first six months after the injury and is usually more gradual after that. Most improvements can be expected within two years of the injury.


The most common cognitive impairment among severely head-injured survivors is memory loss, characterized by some loss of older memories and the partial inability to retain new memories. Some of these patients may experience post-traumatic amnesia, which can involve the complete loss of memories either before or after the injury.

Concentration and attention

Many survivors with even mild to moderate head injuries who experience cognitive deficits become easily confused or distracted and have problems with concentration and attention.

Executive functioning

Many individuals with a mild to moderate TBI also have problems with higher level, so-called "executive" functions, such as planning, organizing, abstract reasoning, problem solving, and making judgments. This disability may make it difficult to return to the same job or school setting the individual was in before the injury.

Language and communication

Language and communication are frequent problems for TBI survivors. Some individuals have trouble recalling words and speaking or writing in complete sentences (called non-fluent aphasia). They may speak in broken phrases and pause frequently. They are usually aware of what is happening and may become extremely frustrated.

Other survivors may speak in complete sentences and use correct grammar but for the listener the speech is pure gibberish, full of invented or meaningless words (called fluent aphasia). TBI survivors with this problem are often unaware that they make little sense and become angry with others for not understanding them.

Other survivors can think of the appropriate language but cannot easily speak the words because they are unable to use the muscles needed to form the words and produce the sounds (called dysarthria). Speech is slow, slurred, and garbled.

Akinetic Mutism

Impairment of the Senses

Many TBI survivors have problems with one of the five senses, especially vision. They may not register what they are seeing or may be slow to recognize objects. Some individuals develop tinnitus, a ringing or roaring in the ears. Others may develop a persistent bitter taste in the mouth or complain of a constant foul smell. Some TBI survivors feel persistent skin tingling, itching, or pain. Although rare, these conditions are hard to treat.

Impairment of Hand-Eye Coordination

TBI survivors often have difficulty with hand-eye coordination. Because of this, they may be prone to bumping into or dropping objects or may seem generally unsteady. They may have difficulty driving a car, working complex machinery, or playing sports.

Emotional and Behavioral Problems

TBI survivors can have emotional and behavioral problems. Family members often find that personality changes and behavioral problems are the most difficult disabilities to deal with. Emotional problems can include depression, apathy, anxiety, irritability, anger, paranoia, confusion, frustration, agitation, difficulty sleeping, and mood swings. Problem behaviors may include aggression and violence, impulsiveness, loss of inhibitions, acting out, being uncooperative, emotional outbursts, childish behavior, impaired self-control, impaired self awareness, inability to take responsibility or accept criticism, being concerned only with oneself, inappropriate sexual activity, and alcohol or drug abuse. Sometimes TBI survivors stop maturing emotionally, socially, or psychologically after the trauma, which is a particularly serious problem for children and young adults. Many TBI survivors who show psychiatric or behavioral problems can be helped with medication and psychotherapy.

See also Inflammation and Neuroprotection in Traumatic Brain Injury

What Other Long-Term Problems Can be Associated With a TBI?

Alzheimer's Disease (AD)

AD is a degenerative disease in which the individual suffers progressive loss of memory and other cognitive abilities. Recent research suggests an association between head injury in early adulthood and the development of AD later in life; the more severe the head injury, the greater the risk of developing AD. Some evidence indicates that a head injury may interact with other factors to trigger the disease and may hasten the onset of the disease in individuals already at risk.

Parkinson's Disease and Other Motor Problems

Parkinson's disease may develop years after TBI if the part of the brain called the basal ganglia was injured. Symptoms of Parkinson's disease include tremors, rigidity or stiffness, slow movement or inability to move, a shuffling walk, and stooped posture. Despite many scientific advances in recent years, no cure has yet been discovered and the disease progresses in severity.

Other movement disorders that may develop after TBI include tremor, uncoordinated muscle movements, and sudden contractions of muscles.

Learn about the kinds of TBI recovery and rehabilitation used for survivors.