Loose Bowel Movements – Diagnosis of Causes Based on Symptoms

The term loose bowel movements refer to watery stool and abnormally frequent bowel movements which are collectively referred to as diarrhea. There are many different causes of diarrhea and it can be difficult to isolate the exact cause in acute cases. Most of the time the diarrhea passes after a few days without any complications. However, understanding the cause of the diarrhea can help with the treatment and prevention of future episodes.

Read more on watery stool.

Find the Cause of Diarrhea from Symptoms

It is difficult to isolate the exact cause of diarrhea solely based on the symptoms. There is a large degree of overlap of the concomitant symptoms among the different causes of loose bowel movements. The only way to know the exact cause of diarrhea is to conduct the relevant tests for diarrhea.

Causes of Diarrhea in Newborns

A newborn normally psses stool up to 8 to 10 times a day. Diarrhea with the following symptoms may be due to causes discussed below:

  • Fever and vomiting with diarrhea is usually due to infections and particularly viral infections (rotavirus) and less commonly due to other microbes.
  • Mild diarrhea: overfeeding.
  • Skin rash, strain to vomiting (gagging), irritability, diarrhea:allergy to cow’s milk or soy formula;
  • Diarrhea in first 3 days of life could be due to congenital diseases of the liver, pancreas, biliary tract, small or large intestine.

Infant and Toddler Diarrhea


  • Fever, vomiting, diarrhea: rotavirus; less commonly: bacteria, parasites, middle ear and urinary tract infections, intusussception, hemolytic-uremic syndrome;
  • Mild diarrhea: newly introduced food, liquid starvation diet,food allergies, antibiotics.

Although diarrhea is not a symptom of teething, many parents find a change in bowel habit when children are experiencing new teeth erupt. This could be related to the pain response.


  • Diarrhea with undigested food particles without other symptoms may be due to consuming excessive amounts of certain foods and beverages like fruit juices (toddler’s diarrhea).
  • Constipation, alternating with diarrhea: bowel disturbances that can occur after acute diarrhea.
  • Coughing, hives, face flushing, watery/bloody diarrhea: food allergy;
  • Skin rash, underweight, watery/bloody diarrhea: intestinal parasites, including intestinal worms, celiac disease, autoimmune enteropathy; rarely: Crohn’s disease, ulcerative colitis, tuberculosis, AIDS, cystic fibrosis, congenital diseases of biliary tract, liver, pancreas or intestine, surgery of small intestine, marasmus, kwashiorkor, zinc deficiency.
  • Diarrhea faked by child’s caregiver (usually mother): factitious diarrhea, Munchausen by Proxy Syndrome (1).

Diarrhea in Older Children and Adults


  • Sudden diarrhea: bacterial, viral or protozoal infections, the ingestion of toxins or poisons including heavy metals, and drug-induced diarrhea. Also refer to explosive diarrhea.
  • Mild (recurrent) diarrhea: stress, medications, bowel investigation or surgery, parasites, appendicitis, diarrhea in pregnancy.
  • Diarrhea after eating with vomiting: food poisoning (spoiled or contaminated food, mushrooms, tropical fish, alcohol), consuming poisonous plants or with acute gastroenteritis.


  • Diarrhea after eating: IBS,lactose intolerance,food allergies, rapid gastric emptying (dumping syndrome), carcinoid syndrome;
  • Mild chronic diarrhea: fructose malabsorption, diabetes, alcoholism,pregnancy;rarely: collagenous/lymphocytic colitis, neuroendocrine tumors;
  • Weight loss, bloody diarrhea, recurrent fever, skin rash: Crohn’s disease, ulcerative colitis, typhoid fever, chronic infection (tuberculosis, AIDS, HSV, CMV);
  • Weight loss, bloating, pale loose stool: malabsorption due to gallbladder, liver or pancreatic disease, Crohn’s disease, celiac disease, small intestinal bacterial overgrowth (SIBO) , chronic infection, or laxative abuse; rare: tropical sprue, Whipple disease, intestinal lymphoma, systemic sclerosis, amyloidosis.
  • Mucus in the bowel movement: IBS, parasites
  • White coated tongue, fatigue, sugar craving, anal itching: candida (see other candida symptoms);
  • Diarrhea after travel: parasites, tropical sprue;
  • Constipation/diarrhea in children: encopresis, post-infectious irritable bowel syndrome;
  • Weakness, dizziness, salt craving: dehydration or Addison’s disease;
  • Irritability, sweating, bulging eyes, enlarged thyroid, weight loss, diarrhea: hyperthyroidism;
  • Leg swelling, mucous diarrhea: protein-losing enteropathy (in ulcerations of the esophagus, stomach or duodenum, Crohn’s disease, intestinal lymphangiectasia, tuberculosis, lymphoma, congestive heart failure, carcinoid syndrome etc), (2).

A diagnosis of irritable bowel syndrome and specifically diarrhea-predominant IBS is made when there are no identifiable causes of chronic diarrhea despite its presence. This has to also be accompanied by symptoms like episodes of abdominal pain.

Typical Causes of Diarrhea in Old People


  • Constipation and/or diarrhea: diverticulitis, ischemic colitis, partial obstruction of the colon or small intestine (fecal impaction, polyps, cancer, adhesions);
  • Pins and needles sensations in hands and feet, early satiety, diarrhea, blurred vision, difficult swallowing, urine retention/incontinence, fainting, etc: autonomic neuropathy (in diabetes, alcoholism, Parkinson’s disease, vit B12/folate deficiency, Sjögren syndrome, SLE, amyloidosis);
  • Diarrhea after eating: carcinoid, VIPoma;
  • Mild constant diarrhea: small intestinal bacterial overgrowth, intestinal lymphoma, systemic sclerosis.

Abdominal Pain and Diarrhea

Exact location of abdominal pain may help in finding the cause of diarrhea.

  • Upper right quadrant: gallbladder, biliary tract, liver disease; rarely: duodenal, pancreatic disease;
  • Upper middle abdomen: gastric, duodenal, pancreatic disease;
  • Upper left quadrant (rarely): gastroenteritis, pancreatic disease;
  • Lower right quadrant: Crohn’s disease, appendicitis;
  • Lower left quadrant: Ulcerative colitis, diverticulitis, ischemic colitis; rarely: colorectal cancer.

Causes of right side and left side abdominal pain.

How Can a Doctor Find the Cause of Diarrhea?

A thorough case history and medical examination may suffice in finding the possible cause of loose bowel movements. It is therefore important to provide sufficient information to a doctor about the events and foods preceding the onset of diarrhea in particular. Blood tests, stool tests and imaging studies may also be conducted to make or confirm a diagnosis.

History. A doctor may ask you:

  • When did diarrhea start?
  • Color and consistency of the stool, any blood or mucus?
  • Is diarrhea related to meals, stress, or daytime? Any recent travel in tropics?
  • Fever, abdominal pain or other symptoms?
  • Diet, alcohol intake?
  • Chronic disease, medications, recent investigation or surgery?
  • Family members: anyone has diarrhea or chronic disease?

Physical examination. Doctor will look for signs of underlying disease:

  • Skin: rash, jaundice, pale skin, scaling, turgor;
  • Abdomen: distension or lumps, enlarged liver or spleen, painful spots;
  • Neck: enlarged thyroid, lymph nodes;
  • Rectal examination: internal hemorrhoids, polyps, inflamed skin around the anus, fistula.

Related Articles:


  1. Munchousen by proxy syndrome  (kidshealth.org)
  2. Protein losing enteropathy  (emedicine.com)
About Jan Modric (209 Articles)
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