A concussion can make your stomach hurt. While head injuries are primarily known for their impact on brain function, causing symptoms like headaches or dizziness, their effects can extend throughout the body, including the digestive system. Gastrointestinal distress is a recognized aspect of recovery for some individuals after a concussion.
The Brain-Gut Connection
The brain and the gut are in constant, bidirectional communication through what is often referred to as the “brain-gut axis.” This complex network involves direct physical connections, such as the vagus nerve, which acts like a major highway carrying signals in both directions between the brain and the digestive tract. Beyond nerves, this communication also involves chemical messengers like hormones and neurotransmitters. Many neurotransmitters, including serotonin, are produced in the gut, influencing both digestive function and mood.
This intricate connection explains why emotional states, like stress or anxiety, can manifest as physical symptoms in the stomach, such as butterflies or nausea. The gut’s own nervous system, the enteric nervous system (ENS), sometimes called the “second brain,” operates locally but also responds to signals from the brain and the autonomic nervous system. This constant dialogue shows how a brain injury, like a concussion, can disrupt normal digestive processes.
How Concussions Affect the Gut
A concussion can disrupt the autonomic nervous system (ANS), which controls involuntary bodily functions including digestion. The ANS has two main branches: the sympathetic nervous system (“fight-or-flight”) and the parasympathetic nervous system (“rest-and-digest”). After a concussion, increased sympathetic activity can lead to an imbalance, altering gut motility and reducing stomach acid and digestive enzyme production. This dysregulation can cause various digestive issues, such as stomach cramps, heartburn, bloating, gas, diarrhea, constipation, and abdominal pain.
The vagus nerve, a major component of the parasympathetic nervous system, plays a role in regulating digestion. A concussion can impair or overstimulate the vagus nerve’s function, leading to symptoms like nausea, gastroparesis (slowed stomach emptying), and even irritable bowel syndrome (IBS). This nerve directly connects the brain to the stomach, and its dysfunction can disrupt the coordinated movements of the digestive tract.
Brain injuries can also trigger a systemic inflammatory response that extends beyond the brain and affects the gut. This inflammation can lead to increased intestinal permeability, sometimes called “leaky gut,” where the gut lining becomes more permeable to toxins and pathogens. Such changes can alter the gut microbiome, the community of bacteria residing in the intestines, potentially leading to an imbalance that further contributes to gut inflammation and digestive problems.
The physical and psychological stress associated with a concussion can exacerbate gut symptoms through the activation of the hypothalamus-pituitary-adrenal (HPA) axis, which releases stress hormones like cortisol. Elevated cortisol levels can contribute to digestive difficulties and dysbiosis, an imbalance in gut microbes. Indirect effects also play a role, including changes in diet due to nausea or loss of appetite, medication side effects, or sleep disturbances commonly experienced after a concussion.
Associated Concussion Symptoms
Stomach pain after a concussion is often one symptom among a broader range of effects. Concussions can manifest with a variety of cognitive symptoms, such as confusion, difficulty concentrating, feeling “in a fog,” and problems with memory. Individuals might experience amnesia around the event that caused the concussion. These cognitive changes can sometimes be subtle and not appear immediately after the injury.
Physical symptoms are also common, including headaches, dizziness, and fatigue or drowsiness. Sensitivity to light and noise, blurred vision, and ringing in the ears are frequently reported. Balance problems and nausea or vomiting, particularly early on, are also recognized signs of a concussion.
Beyond physical and cognitive changes, concussions can lead to emotional and behavioral symptoms. These may include irritability, anxiety, feeling more emotional than usual, or even sadness and depression. Sleep disturbances, such as sleeping more or less than usual, or trouble falling asleep, are also common.
When to Consult a Doctor
Seeking medical attention after a head injury is important, even if symptoms seem mild. If you or someone you know experiences a head injury, it is advisable to see a healthcare professional within one to two days for evaluation. Children and adolescents should be seen by a professional trained in pediatric concussions.
Immediate emergency care is necessary if certain red flag symptoms appear after a head injury. These include:
- Repeated vomiting or nausea.
- A headache that worsens or does not go away.
- Any loss of consciousness lasting longer than 30 seconds.
- Seizures or convulsions.
- Slurred speech.
- Weakness or numbness in the arms or legs.
- Changes in behavior like increasing confusion, restlessness, or agitation.
- Any fluid or blood draining from the nose or ears.
- Vision changes such as one pupil being larger than the other.
For persistent stomach pain, ongoing concussion symptoms that do not improve, or any new or worsening symptoms, a medical evaluation is recommended. Only a medical professional can accurately diagnose a concussion, assess the extent of the injury, and rule out other potential causes for symptoms. Rest is generally advised for recovery, and avoiding activities that worsen symptoms is also helpful.