The Link Between Chronic Pain, Nausea and Vomiting

Table of Contents

1. Pain Signals
2. Triggers for Pain-Related Nausea and Vomiting
3. Address the Source of Chronic Pain to Manage Nausea and Vomiting

Chronic pain, a complex condition that persists for more than six months, affects over 24% of adults in the U.S. It is not just a physical sensation, but a multifaceted experience that can cause various symptoms, including nausea and vomiting. Chronic pain and nausea share overlapping pathways in the central nervous system (CNS) and the autonomic nervous system (ANS). While the specific path may differ for various health conditions, the experience of nausea and vomiting is a typical response when the brain receives signals from chronic pain.

Pain Signals

The gut-brain axis is the continuous communication network between the gastrointestinal tract and the brain. This axis involves more than the digestive system. It also includes:

• The spinal cord
• The brainstem
• Vagal nerves in the parasympathetic nervous system that connect the brain to various organs, controlling functions like digestion and the immune system
• The limbic system, which is involved in emotions and memory
• The interoception region, where the brain processes internal bodily signals
• The autonomic nervous system is responsible for involuntary bodily functions
• Motor outputs

Certain areas, like the brainstem, are key sites for producing nausea or vomiting. The brainstem’s components include the vagal nerves, the solitary tract (fiber bundle) that carries sensory information, and a cluster of nerve cells called the dorsal motor nucleus that controls bodily functions.

Cells in the mucous in the gastrointestinal tract, the nervous system in the tract’s wall, and the vagus and splanchnic nerves that carry autonomic signals and run along each side of the spinal column are also involved. When you feel pain so bad that you throw up, it is likely due to the autonomic nervous system responding by releasing stress hormones and activating other systems that disrupt the gut-brain signaling system.

Other pain pathways also exist. For example, pain may be caused by nerve damage or inflammation outside the gut-brain axis. Neuropathic pain due to diabetes or inflammatory pain caused by fibromyalgia or arthritis can also trigger pain signals that lead to nausea and vomiting.

Triggers for Pain-Related Nausea and Vomiting

Why does pain cause vomiting or nausea? Pain and nausea feelings are processed in the brainstem, and the triggers for nausea and vomiting have various sources. Nausea and vomiting are biological responses. In response to pain, the brain triggers the release of serotonin as a stress response, followed by the production of cortisol as an anti-inflammatory. Serotonin is a neurotransmitter that stimulates gut and brain receptors that produce nausea and vomiting. Cortisol is a stress hormone that disrupts the digestive process.

Nausea can result from various health ailments, while vomiting is controlled by the brain’s autonomic nervous system (ANS). As mentioned, there are times when a health condition outside the gut-brain axis is linked to pain and nausea.

For example, back pain and nausea are linked. A back condition causing pain may irritate a vagus nerve that runs alongside the spine, which causes the brain to respond. Referred pain can also lead to nausea and vomiting because the nerves in the body are connected. An issue in the muscles or spine sends pain signals that affect the stomach, leading to nausea and vomiting.

Some of the common conditions causing chronic pain that frequently lead to nausea and vomiting include the following.

Migraine

Migraines are complex and more than headaches. They are still not fully understood, but common symptoms include nausea and vomiting. Research has found that migraines are marked by abnormal nerve and chemical signaling and abnormal activity in the brain’s blood vessels.

Back pain

Many conditions can cause back pain. They include gastrointestinal issues causing radiating pain, kidney problems, and spinal issues like herniated discs. It can be a two-way street. Pain related to the gastrointestinal system may radiate to the back, or a back problem may cause pain to radiate to the digestive system. Sometimes, a back condition irritates the vagus nerve, which is involved in digestion, and triggers a response like nausea. Musculoskeletal inflammation can also lead to back pain and nausea as chemicals are released that disrupt the digestive system. These health issues can cause pain so bad it makes you nauseous or leads to vomiting, an involuntary response due to something in the digestive system.

Fibromyalgia

Fibromyalgia is a health condition in which people experience widespread chronic pain. It may have many symptoms, but it is often associated with back pain and gastrointestinal issues like constipation and bloating. People with fibromyalgia have increased pain sensitivity. Researchers have found evidence that the signaling in neural pathways is altered.

Fibromyalgia frequently causes nausea, likely due to gastrointestinal conditions often present, like irritable bowel syndrome, or symptoms like tension headaches.

Chronic pancreatitis

The pancreas produces the enzymes needed for digesting food. When inflamed, the pancreas cannot properly digest food because the enzymes cannot reach the intestine. The trapped enzymes can slowly damage the pancreas. The symptoms of chronic pancreatitis include pain in the abdomen that spreads to the back and nausea and vomiting.

These are not the only conditions linking chronic pain with nausea and vomiting. For example, cancer pain and opioid use can disrupt the digestive system.

Address the Source of Chronic Pain to Manage Nausea and Vomiting

Nausea and vomiting are frequent consequences of chronic pain because pain and these symptoms share neurological and physiological pathways. Pain sets off a series of events that impact signals sent through the network of nerves, including in the gastrointestinal system. It is crucial to work with a pain management specialist to determine the best intervention to manage the pain and its symptoms. Many pharmacological and non-pharmacological treatments are available today to help manage chronic pain and reduce nausea and vomiting episodes.

Sources

1. https://www.cdc.gov/nchs/products/databriefs/db518.htm
2. https: //pmc.ncbi.nlm.nih.gov/articles/PMC8198651/
3. https://www.ncbi.nlm.nih.gov/books/NBK560504/
4. https://pmc.ncbi.nlm.nih.gov/articles/PMC4263906/
5. https://www.ninds.nih.gov/health-information/disorders/migraine
6. https://pmc.ncbi.nlm.nih.gov/articles/PMC4699282/
7. https://www.niams.nih.gov/health-topics/fibromyalgia
8. https://pmc.ncbi.nlm.nih.gov/articles/PMC3394355/
9. https://www.nhs.uk/conditions/chronic-pancreatitis/