A brain bleed, also known as an intracranial hemorrhage, involves bleeding within the skull, often resulting from a head injury. When blood accumulates inside the skull, it exerts pressure on the brain. This pressure can prevent oxygen and nutrients from reaching brain tissues, potentially causing damage. Any bleeding inside the skull or brain constitutes a medical emergency.
Types of Brain Bleeds After Head Injury
Head injuries can lead to several types of brain bleeds, each defined by its location within the skull.
One type is an epidural hematoma, where blood collects between the skull and the dura mater, the outermost protective membrane covering the brain. This bleed often involves a ruptured artery, leading to rapid blood accumulation.
Another common type is a subdural hematoma, which occurs when blood gathers between the dura mater and the arachnoid membrane, the layer directly beneath the dura. Subdural hematomas usually result from tears in bridging veins, which bleed more slowly than arteries. These can be classified as acute, subacute, or chronic, depending on how quickly symptoms develop.
A subarachnoid hemorrhage involves bleeding into the subarachnoid space, the area between the brain and its surrounding membranes. Bleeding in this region can be caused by trauma. An intracerebral hemorrhage refers to bleeding directly within the brain tissue itself, which can occur in various parts of the brain following a head injury.
The Critical Timeline for Symptom Onset
Symptoms of a brain bleed are not always immediate following a head injury and can be delayed by hours, days, or even weeks. The specific type of bleed and the rate at which blood accumulates largely determine when signs begin to appear.
Epidural hematomas are known for a “lucid interval,” where an injured person may briefly lose consciousness, then regain alertness and seem fine, only to experience a rapid decline hours later. This period of apparent normalcy can last from a few minutes to several hours, typically within 2 to 6 hours, though it can extend up to 24 hours. The swift deterioration is due to the high-pressure arterial bleeding quickly compressing the brain.
Subdural hematomas exhibit varying timelines for symptom onset. Acute subdural hematomas cause severe symptoms that typically appear within minutes to hours after the head injury. Subacute subdural hematomas have a slower rate of bleeding, and their symptoms may emerge over days or even weeks following the trauma. Chronic subdural hematomas, more common in older individuals, can develop very slowly, with symptoms not appearing until weeks or even months after a minor head injury, which the person may not even recall.
Subarachnoid hemorrhages can cause a sudden, severe headache, often described as a “thunderclap” headache, appearing almost immediately. However, other symptoms might evolve over several hours. Intracerebral hemorrhages can also have a sudden onset of symptoms, or they may progress gradually over minutes to hours depending on the location and size of the bleed.
Recognizing Warning Signs
After a head injury, observing specific signs and symptoms can indicate a potential brain bleed. A severe or worsening headache is a common symptom, often accompanied by confusion or disorientation. Individuals might also exhibit slurred speech, difficulty waking up, or unusual behavioral changes such as increased irritability or memory loss.
Physical indicators include repeated episodes of nausea and vomiting. Weakness or numbness on one side of the body, problems with balance, or dizziness are important signs. Vision changes, such as blurred or double vision, or pupils that are unequal in size, are concerning. Seizures or any loss of consciousness, even brief, are serious warning signs. A stiff neck can also be present.
In infants and young children, symptoms can differ. Parents should watch for:
Persistent crying
Refusal to eat
Unusual sleepiness
A bulging soft spot on the head
Lethargy
Irritability
Feeding difficulties
Abnormal eye movements
When to Seek Immediate Medical Attention
If a head injury involves loss of consciousness, confusion, or any of the warning signs discussed, immediate medical evaluation is necessary. This applies even if symptoms seem minor or appear hours or days after the initial impact.
It is important to call emergency services or go to the nearest emergency room without delay if a brain bleed is suspected. Driving oneself or an injured person to the hospital is not advisable, as emergency medical services can provide care en route. Inform medical staff about the head injury, including when it occurred and any symptoms observed. Prompt medical attention can significantly improve outcomes.