When That Pain In Your Stomach Really Is In Your Head

Gut issues can be caused by brain injury.

As with certain forms of limbic encephalitis,142,148,149 limbic encephalopathy resulting from mefloquine intoxication may also progress to involve the brainstem,40 and consequently users of mefloquine may experience numerous physical symptoms, including nausea and emesis, which are broadly referable to interconnected limbic and brainstem centers.150Additional probable brainstem symptoms reported with mefloquine use include vertigo, disequilibrium, nystagmus, photophobia, and accommodative dysfunction suggestive of involvement of the vestibuloocular nuclei40,70,151; paresthesias of the extremities and face,43,45,70,152 suggestive of posterior column153 or trigeminal nerve nuclei involvement; autonomic dysfunction including temperature sensitivity,39 bradycardia, bradypnea, and postural orthostatic tachycardia syndrome45,154,155; and gastrointestinal complaints including abdominal pain,156 esophageal dysmotility, anorexia,45 and diarrhea, signaling possible involvement of the vagus nerve dorsal motor nuclei. Rare reports of anticholinergic syndrome157 may indicate further brainstem involvement.

Elspeth Cameron Ritchie, Jerald Block and Remington Lee Nevin
Journal of the American Academy of Psychiatry and the Law Online June 2013, 41 (2) 224-235; Psychiatric Side Effects of Mefloquine: Applications to Forensic Psychiatry

If you were to ask somebody what they thought might cause a person to have the diarrhea, chances are you wouldn’t hear brain damage. A stomach virus might come to mind, or maybe Taco Bell for lunch, but brain damage? Wouldn’t even crack the top five I’d bet.

But surprisingly enough, diarrhea can be caused by brain damage, as can a number of other gastrointestinal complaints. This is because the brain has a direct link to your digestive system via the vagus nerve, the longest nerve in the human body.

vagus nerve

Biology 101: The Nervous System

The human body is to large degree controlled unconsciously by the autonomic nervous system. These are the nerves that control the internal organs, including the blood vessels, stomach, intestine, liver, kidneys, bladder, genitals, lungs, pupils, heart, and sweat, salivary, and digestive glands. 

The autonomic nervous system is comprised of two parts, the parasympathetic nervous system and the sympathetic nervous system. It is through the sympathetic nervous system that the “fight or flight” response is controlled, while the parasympathetic nervous system is sometimes called the “rest and digest” system.

All of the nerves in the body either go through or originate in the brain stem. The vagus nerve is one of twelve cranial nerves that send messages to the entire body. It originates in the brain stem, and travels down the visceral tract and branches out to serve the larynx and esophagus, the trachea, lungs, and heart, as well as most of the digestive tract.


In the digestive tract, its function is to stimulate the involuntary contractions which assist in the movement of food through it. If the nerve is stimulated at certain points, like in the esophagus, it can trigger a reaction which causes fainting, as the President George W. Bush found out in 2002 after eating a pretzel.

Bush Faints While Eating A Pretzel


Brainstem damage due to quinoline toxicity.

Across the globe, many thousands now have chronic quinoline encephalopathy, or quinism, as a result of taking the anti-malarial drugs mefloquine or tafenoquine. The exact number isn’t known but is likely to be in the tens of thousands at least.

A very significant minority of the people who took the drug suffered damage to their brainstems. As a result, there is a disruption in communication between the brain and some of the body’s systems, and those with quinism suffer from a wide range of symptoms as a result. Some of these symptoms involve the digestive tract, with complaints like trouble swallowing,indigestion, heartburn, stomach pain, and diarrhea.


PTSD vs. quinism

It is routine for someone with quinism to be diagnosed as having PTSD, since the two share a number of symptoms and these symptoms are psychological in nature (ie depression, rages, etc.).

What distinguishes quinoline toxicity is the presence of physical symptoms which are the result of damage to the brainstem. Such things as tinnitus, sudden headache, tingling or loss of feeling in the extremities, indigestion, heartburn, and diarrhea are among the physical symptoms that are not manifest in a diagnosis of PTSD.

Diagnosed with PTSD but have these symptoms?

If you’ve taken mefloquine or tafenoquine, have been diagnosed with PTSD, and have the above symptoms, it is a good indicator that you actually have chronic quinoline encephalopathy and you should discuss this with your physician.

For more information

Visit the Quinism Foundation at https://quinism.org/ to learn more about quinism or to make a donation.

3 thoughts on “When That Pain In Your Stomach Really Is In Your Head

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