A concussion is a mild traumatic brain injury that temporarily affects brain function. It results from a head or body impact causing the brain to move rapidly within the skull, leading to chemical changes and sometimes damage to brain cells. While concussions can cause a range of symptoms, they typically do not cause a fever. If a fever develops after a head injury, it is an important symptom that indicates a cause other than the concussion itself.
Concussions and Body Temperature Regulation
The body’s internal temperature is regulated by the hypothalamus, a part of the brain. This area functions like a thermostat, monitoring temperature and making adjustments to maintain a stable internal environment, known as homeostasis. It coordinates responses like sweating or shivering to balance heat production and loss.
Concussions involve temporary alterations in brain function, rather than widespread structural damage that would disrupt the hypothalamus. The injury causes the brain to move within the skull, leading to chemical changes. While a head injury can sometimes lead to mild inflammation, a significant or persistent fever is not a direct result of a concussion.
Fever After Head Injury: Other Causes
A fever following a head injury often points to a serious underlying issue that requires prompt medical evaluation. One cause is an infection, such as meningitis, an inflammation of the membranes surrounding the brain and spinal cord. Infections can arise from open wounds, skull fractures, or bacteria entering the bloodstream. Meningitis symptoms can include fever, severe headache, and neck stiffness.
Another cause of fever after head trauma is a severe brain injury, such as a subarachnoid hemorrhage. This involves bleeding around the brain, which can disrupt the hypothalamus or trigger an inflammatory response leading to fever. Fever is common in patients with subarachnoid hemorrhage, and in many cases, an infectious source cannot be identified, suggesting a direct neurological cause.
A fever could also stem from a systemic infection unrelated to the head injury, such such as the flu or a common cold. Individuals with brain injuries may be more susceptible to various infections, including urinary tract infections or respiratory infections, which can manifest with fever. Environmental factors, such as heatstroke, could also cause an elevated body temperature if the head injury occurred in a hot environment, leading to the body’s inability to regulate its temperature effectively.
When to Seek Urgent Medical Care
Any fever after a head injury is a warning sign warranting immediate medical attention. A medical professional must evaluate the situation to rule out serious underlying conditions. Beyond fever, other symptoms signal the need for urgent medical care.
Red flag symptoms include a headache that worsens or does not go away, repeated vomiting, or seizures. Changes in consciousness, such as loss of consciousness, difficulty staying awake, or unusual drowsiness, require immediate attention. Other signs are slurred speech, confusion, weakness or numbness, and changes in pupil size or vision problems. Clear fluid draining from the nose or ears, or neck stiffness, indicate a potentially serious injury requiring prompt medical assessment.