Nausea and vomiting are common symptoms following a concussion, often occurring as the brain reacts to the chemical and physical changes caused by a head impact. While a single episode of vomiting or a persistent feeling of nausea can be a normal part of the body’s response to a minor head injury, these symptoms must be monitored closely to ensure they do not worsen over time. Understanding the difference between expected recovery symptoms and critical red flags is essential for anyone caring for a person with a suspected brain injury.
What We’ll Discuss in This Article
- The biological reasons why head injuries trigger nausea and vomiting.
- The difference between a single episode of vomiting and repeated occurrences.
- How the vestibular system and brain chemistry contribute to feeling sick.
- Monitoring protocols for children and adults during the first 48 hours.
- Specific signs that indicate vomiting is a medical emergency.
- Tips for managing nausea during the initial stages of concussion recovery.
Why Concussions Cause Nausea and Vomiting
Nausea and vomiting after a head injury occur because the brain’s delicate internal environment is disrupted by the force of the impact. When the brain moves rapidly inside the skull, it can affect the areas responsible for controlling the “vomiting centre” and the vestibular system, which manages balance and spatial orientation. According to the NHS, a concussion is a temporary injury to the brain caused by a bump, blow, or jolt to the head.
This disruption creates a sensory mismatch where the signals sent to the brain regarding movement and position do not align with what the eyes see. This conflict often results in a feeling of motion sickness or general nausea. Additionally, the chemical changes that happen at a cellular level as the brain attempts to repair itself can lead to a general feeling of malaise and gastric distress.
Differentiating Between Minor and Serious Symptoms
In the context of a minor head injury, a person may feel sick or vomit once shortly after the event, which is often a result of the shock and physical trauma. However, clinicians draw a significant distinction between a one off event and repeated vomiting. The National Institute for Health and Care Excellence provides guidelines on the clinical assessment of head injuries to identify when vomiting indicates increased pressure on the brain.
Repeated vomiting, especially if it is forceful or occurs several hours after the initial injury, is a major red flag. This can suggest that there is swelling or bleeding inside the skull that is putting pressure on the brain tissue. While nausea is a common and often lingering symptom of a minor concussion, vomiting more than once requires an immediate emergency medical assessment to rule out more serious complications.
Comparison of Nausea and Vomiting Severity
The following table helps categorise the level of concern regarding sickness symptoms following a head impact.
| Symptom Pattern | Clinical Category | Recommended Action |
| Feeling sick (nausea) | Minor symptom | Rest and monitor at home. |
| Vomiting once | Minor symptom | Monitor closely for 48 hours. |
| Repeated vomiting | Red flag symptom | Immediate emergency medical care. |
| Vomiting with drowsiness | Serious emergency | Call 999 immediately. |
| Projectile vomiting | Serious emergency | Call 999 immediately. |
Managing Nausea During Recovery
The primary treatment for nausea following a concussion is rest, as physical and mental exertion can make the feeling of sickness worse. Avoiding bright lights, loud noises, and digital screens can help reduce the sensory load on the brain, which often decreases the intensity of nausea. It is important to stay hydrated by taking small, frequent sips of water, as dehydration can mimic and worsen the feelings of dizziness and sickness.
During the first 48 hours, the person should not be given any medication to stop vomiting unless specifically directed by a doctor, as these medicines can mask the progression of the injury. If nausea is accompanied by a mild headache, paracetamol is usually the recommended choice for pain relief. Avoiding alcohol is mandatory, as it interferes with brain healing and significantly increases the likelihood of nausea and imbalance.
Sickness Symptoms in Children and Infants
In children, vomiting is a very common response to any type of physical trauma or stress, but it must still be treated with high vigilance after a head injury. Parents should look for other signs accompanying the sickness, such as excessive crying, changes in eating habits, or a lack of interest in play. In infants, projectile vomiting or a refusal to nurse can be early indicators of a more significant brain injury.
Because children may not be able to describe the feeling of nausea, caregivers should watch for “non-verbal” cues like paleness, lethargy, or a sudden quietness. If a child vomits more than once or seems unusually drowsy after being sick, they must be taken to an emergency department for a professional evaluation. The 48-hour monitoring window is particularly important for children due to the developing nature of their brains and thinner skull bones.
When Vomiting Indicates a Medical Emergency
While nausea is a frequent part of a concussion, specific patterns of vomiting move the situation into a life threatening category. These symptoms suggest that the intracranial pressure is rising, which can lead to permanent brain damage if not treated. If vomiting is combined with a worsening headache, confusion, or weakness in the limbs, the situation is critical.
If a person becomes difficult to wake after being sick, or if they experience a seizure, this indicates a severe head injury. In these cases, the focus shifts from managing a concussion to emergency interventions. Always trust your instincts if the person’s condition seems to be deteriorating, regardless of whether they have only vomited once or multiple times.
Conclusion
Nausea and a single episode of vomiting are common symptoms of a concussion as the brain manages the chemical disruption of an impact. However, repeated vomiting is a serious red flag that requires immediate clinical intervention to rule out internal bleeding or swelling. Monitoring these symptoms during the first 48 hours is the most effective way to ensure a safe recovery. If you experience severe, sudden, or worsening symptoms, call 999 immediately.
Is it normal to feel sick for a week after a concussion?
Nausea can persist for several days as the brain restores its chemical balance, but it should gradually improve with rest.
Why does looking at my phone make me feel sick?
The bright light and fast movement on a screen can trigger nausea because your brain is struggling to process sensory information while healing.
Can I eat normally if I feel nauseous?
It is best to stick to light, bland foods and clear fluids until the nausea subsides to avoid further upsetting your system.
Is one episode of vomiting an emergency?
Usually, a single vomit immediately after the injury is not an emergency if the person is otherwise alert, but they must be monitored closely.
What is the difference between nausea and vertigo?
Nausea is the feeling of wanting to be sick, while vertigo is the false sensation that you or your surroundings are spinning.
Can a concussion cause vomiting hours after the hit?
Yes, delayed vomiting can occur, and if it happens more than once, it is a sign that you need an urgent medical assessment.
Should I stop my child from crying if they feel sick?
Crying is a natural response, but if the crying becomes inconsolable or is followed by repeated vomiting, seek medical help immediately.
Authority Snapshot (E-E-A-T Block)
This article provides factual, safe public health information regarding the symptoms of head injuries. It was reviewed by Dr. Stefan Petrov, a UK-trained physician with extensive experience in emergency medicine and diagnostic care. The content follows the clinical assessment and safety standards established by the NHS and NICE to help the public recognise and manage concussions safely.
