Diarrhea is characterized by loose, watery stools that occur more frequently than usual. It is often accompanied by abdominal cramps, which can range from mild to quite painful. Diarrhea and abdominal cramping occur due to abnormalities in the gastrointestinal tract that result in increased motility and excess fluid secretion.
What causes diarrhea?
There are several potential causes of diarrhea:
- Infection – Bacterial, viral, or parasitic infections can disrupt the intestines and lead to diarrhea. Common culprits include norovirus, Salmonella, Campylobacter, C. difficile, and Giardia.
- Medications – Antibiotics, laxatives, chemotherapy drugs, antidepressants, and heart medications can sometimes cause diarrhea as a side effect.
- Dietary changes – Eating too much fiber, artificial sweeteners, greasy foods, or other triggers can cause loose stools.
- Diseases – Conditions like irritable bowel syndrome (IBS), Crohn’s disease, ulcerative colitis, celiac disease, and other malabsorption disorders can lead to chronic diarrhea.
- Food intolerances – Lactose, fructose, or gluten intolerance can make it difficult to digest certain foods, resulting in diarrhea.
- Stress and anxiety – The gut is highly sensitive to emotions and stress. Anxiety and emotional distress can overstimulate the gut and cause diarrhea.
What causes the abdominal cramps and pain?
The abdominal cramps and pain associated with diarrhea occur due to:
- Increased motility – Diarrhea speeds up the passage of stool through the intestines. The rapid contractions of the intestinal muscles produce cramping sensations.
- Inflammation – Infections and other conditions like IBS, IBD, and celiac disease cause inflammation in the intestines, leading to pain and hypersensitivity.
- Intestinal spasms – The intestines go through episodes of spastic, uncoordinated contractions during diarrhea. This causes painful cramps.
- Trapped gas – The rapid transit of stool does not allow enough time for gas to be passed, resulting in bloating and abdominal discomfort.
- Loss of fluids/electrolytes – Dehydration and electrolyte imbalances due to fluid loss can cause muscle spasms and painful cramps throughout the body.
What happens in the intestines during diarrhea?
Here is an overview of the changes that take place in the intestines during diarrhea:
- Increased secretion – The intestines secrete more fluid than normal, resulting in watery stool.
- Decreased absorption – Nutrients and electrolytes are not properly absorbed due to the rapid transit of stool.
- Altered motility – Peristalsis moves faster, forcing out loose stools more frequently.
- Irritation and inflammation – Infections, toxins, and conditions like IBD cause irritation and gut inflammation.
- Disrupted microbiome – Diarrheal illnesses disrupt the balance of intestinal bacteria.
These processes result in loose, watery stools, abdominal cramping, bloating, and urgency to pass stool.
What causes the painful abdominal cramps during diarrhea?
The abdominal cramps are a result of the following intestinal processes:
- Increased muscle contractions – The intestinal muscles contract more frequently and forcefully to propel the loose stools out, resulting in cramping sensations.
- Inflammation – Irritation and inflammation make the intestines hypersensitive, lowering the threshold for painful spasms and cramps.
- Spasms – The intestinal muscle cells can go through uncoordinated, spastic contractions that cause sudden, painful cramps.
- Trapped gas – The rapid movement of stool does not allow enough time for gas to be expelled, leading to gas buildup and bloating.
- Electrolyte imbalances – Loss of fluids and electrolytes like potassium and sodium cause muscle spasms and painful cramping.
Role of serotonin
Serotonin is a neurotransmitter that helps control intestinal motility and sensitivity. Diarrhea often disrupts serotonin signaling in the gut, contributing to cramping and pain.
Why do the cramps come and go in waves?
The abdominal cramps tend to come and go in waves rather than being constant because:
- The intestines go through alternating cycles of contraction and relaxation. Cramps occur during the contraction phase.
- Muscle spasms are episodic rather than continuous. Periods of spasms alternate with periods of calm.
- Pain receptors become fatigued during cramping, temporarily dulling the sensation. But they regain sensitivity again when the cramps subside.
- The amount of irritants and fluid in the intestines varies, causing intermittent stimulation of the nerves.
- Trapped gas and bloating come and go as the gas gets slowly pushed through.
The cyclical nature of intestinal cramping prevents the pain from being constant. But it also means that diarrhea cramps can return just as one bout subsides.
Are cramps always present with diarrhea?
No, abdominal cramping does not necessarily accompany all cases of diarrhea. Mild forms may not cause much cramping. Cramps are also less common in certain types of diarrhea:
- Osmotic diarrhea – Caused by malabsorption of sugars and laxative abuse. The stool contains unabsorbed compounds that draw water into the intestines by osmosis.
- Secretory diarrhea – Caused by bacterial enterotoxins and hormone disorders. The intestines secrete excess fluids without disrupting motility.
- Sluggish motility – Stool transit is actually slower than normal, though contents are very loose.
In these types of diarrhea, the lack of intestinal hurry, cramping, and irritation results in less severe or no abdominal cramps.
Risk factors for severe cramping
Cramping and pain tend to be more pronounced when diarrhea is accompanied by:
- High fever
- Bloody stool
- Severe dehydration
- Underlying conditions like IBD, IBS, celiac disease
- Toxic megacolon
- Intestinal ischemia
- Inflammation and ulcerations
- Rectal pain and tenesmus (feeling of incomplete evacuation)
These signs can indicate a more serious illness and should be evaluated promptly by a doctor.
Does the intensity of cramps correlate with stool frequency?
Yes, often the severity of abdominal cramping correlates with the frequency of diarrhea:
- Mild cramping may occur with 2-3 loose stools per day.
- Moderate cramping may occur with 4-6 watery stools per day.
- Severe cramping may occur with 6+ frequent, liquid stools per day.
However, this depends on the individual. Some people experience intense cramps even with mild diarrhea. Others have frequent diarrhea with minimal cramping.
Conclusion
In summary, diarrhea cramps are caused by:
- Intestinal hurry and hypermotility
- Inflammation and irritation
- Muscle spasms and contractions
- Trapped gas and bloating
- Fluid/electrolyte disturbances
These processes stimulate the intestinal pain nerves, provoking painful muscle cramps that come and go in cycles. While unpleasant, the cramps are usually temporary and improve once the diarrhea resolves.