A concussion, classified as a mild traumatic brain injury (mTBI), results from a jolt or blow to the head or body that causes the brain to move rapidly within the skull. This sudden movement can stretch and damage brain cells, leading to temporary chemical changes that disrupt normal brain function. While a concussion is a brain injury, a fever is generally not a typical symptom associated with it.
Understanding Concussion and Fever
A fever is not commonly associated with a concussion because concussions are primarily functional injuries, involving a temporary disruption of brain function and energy metabolism, rather than direct tissue damage or infection. While head trauma can sometimes cause a “neurogenic fever” due to inflammation or a faulty immune response, this is not a universal or typical concussion symptom. Some individuals with traumatic brain injury (TBI) may experience neurogenic fever, which is a fever with a neurological basis rather than an infection. This type of fever is generally an acute or short-term symptom, but it can indicate a more complicated recovery.
Typical Concussion Symptoms
Concussion symptoms can vary widely among individuals and may not always appear immediately, sometimes taking hours or even days to manifest. Physical symptoms often include headaches, dizziness, balance problems, nausea, vomiting, fatigue, drowsiness, blurred vision, and sensitivity to light or noise. Cognitive symptoms affect thinking and mental processing, such as difficulty concentrating, memory issues, feeling foggy or slowed down, and confusion. Emotional changes are also common, including irritability, anxiety, sadness, depression, or sudden mood swings. Sleep-related disturbances can involve feeling excessively tired, having trouble falling asleep, or sleeping more or less than usual.
When a Fever After Head Injury is a Concern
While a fever is not a typical symptom of a concussion, its presence after a head injury is a serious indicator and requires immediate medical evaluation. It can signal underlying complications more severe than a concussion alone. One significant concern is intracranial hemorrhage, which is bleeding in or around the brain. When blood enters brain tissue, its breakdown products can trigger an inflammatory response, leading to the release of cytokines that elevate body temperature. Fever following brain hemorrhage can indicate the severity of the bleeding and is sometimes associated with poorer outcomes.
Another serious cause for fever after a head injury is an infection, such as meningitis or encephalitis. Meningitis is an inflammation of the membranes surrounding the brain and spinal cord, while encephalitis involves inflammation of the brain tissue itself. These infections can occur if a head injury creates a break in the skin or skull, allowing bacteria or other pathogens to enter the nervous system. Symptoms of meningitis and encephalitis often include a sudden fever, severe headache, stiff neck, nausea, vomiting, and changes in behavior or consciousness.
The fever might also be due to unrelated systemic issues, such as a common cold or flu, but it is always safer to rule out head injury complications first. Seeking emergency medical care is necessary if a fever is present after a head injury, especially if accompanied by other concerning symptoms. These include:
- A headache that worsens or does not subside
- Repeated vomiting
- Seizures
- Increasing confusion
- Slurred speech
- Weakness or numbness in the limbs
- Changes in pupil size
Professional medical evaluation is necessary to identify the cause of the fever and ensure appropriate and timely treatment.