Diarrhea: Clinical Meaning

Colitis (Ulcerative Colitis)

Ulcerative colitis is a chronic inflammatory bowel disease causing long-lasting inflammation and ulcers in the digestive tract, primarily affecting the colon and rectum. It leads to abdominal pain, diarrhea with blood, and urgency.

Hyperthyroidism

Hyperthyroidism occurs when the thyroid gland produces too much thyroid hormone, speeding up metabolism. It causes weight loss, rapid heartbeat, anxiety, tremors, and heat intolerance. Graves' disease is the most common cause.

Endometriosis

Endometriosis is a condition where tissue similar to the uterine lining grows outside the uterus. It causes chronic pelvic pain, especially during menstruation, and can lead to infertility. It affects approximately 10% of reproductive-age women.

COVID-19

COVID-19 is an infectious respiratory disease caused by the SARS-CoV-2 virus. Symptoms range from mild (fever, cough, fatigue) to severe (pneumonia, respiratory failure). Long COVID affects some patients with persistent symptoms lasting months.

Colorectal Cancer

Colorectal cancer develops in the colon or rectum and is the third most common cancer globally. Risk factors include age over 50, family history, inflammatory bowel disease, and diet high in red/processed meat.

Typhoid Fever

Typhoid fever is caused by Salmonella typhi, transmitted through contaminated food and water, causing sustained fever, abdominal pain, and rose spots. Antibiotic treatment is effective; vaccination is recommended for travellers to endemic areas.

HIV/AIDS

HIV (Human Immunodeficiency Virus) destroys CD4 T-cells, progressively weakening the immune system until AIDS develops. Antiretroviral therapy suppresses viral load to undetectable levels, enabling near-normal life expectancy.

Norovirus (Stomach Flu)

Norovirus is the leading cause of acute gastroenteritis worldwide, spreading through contaminated food, water, and surfaces. It causes sudden-onset vomiting, diarrhea, and stomach cramps lasting 1-3 days; hydration is the mainstay of treatment.

Salmonellosis

Salmonellosis is a foodborne illness caused by Salmonella bacteria, typically from contaminated poultry, eggs, or raw produce. Symptoms include diarrhea, fever, and abdominal cramps beginning 6-48 hours after exposure; most resolve within a week.

Crohn's Disease

Crohn's disease is a chronic inflammatory bowel disease that can affect any part of the GI tract from mouth to anus, causing abdominal pain, diarrhea, and malnutrition. Skip lesions and transmural inflammation are pathological hallmarks.

Celiac Disease

Celiac disease is an autoimmune reaction to gluten that damages the small intestine villi, impairing nutrient absorption. Symptoms include diarrhea, bloating, weight loss, and fatigue; strict gluten-free diet is the only treatment.

Irritable Bowel Syndrome (IBS)

IBS is a functional gastrointestinal disorder causing recurrent abdominal pain related to defecation, with altered stool frequency or consistency. It affects up to 15% of the population; dietary changes, stress management, and symptom-specific medications help.

Diverticulitis

Diverticulitis occurs when diverticula (small pouches in the colon wall) become inflamed or infected, causing left lower quadrant pain, fever, and bowel changes. Uncomplicated cases are treated with antibiotics; perforation or abscess may require surgery.

Colon Polyps

Colon polyps are growths on the inner lining of the colon that are usually asymptomatic but can develop into colorectal cancer over time. Colonoscopy is the gold standard for detection and polypectomy; surveillance intervals depend on polyp type and size.

SIBO (Small Intestinal Bacterial Overgrowth)

SIBO occurs when excessive bacteria colonize the small intestine, causing bloating, abdominal pain, diarrhea, and malabsorption. It is diagnosed with breath testing and treated with antibiotics and dietary modification.

Dumping Syndrome

Dumping syndrome occurs after gastric surgery when food moves too quickly from the stomach into the small intestine, causing nausea, diarrhea, sweating, and dizziness after meals. Dietary modifications and slower eating are primary management strategies.

Microscopic Colitis

Microscopic colitis causes chronic watery diarrhea with normal colonoscopy appearance but characteristic changes on biopsy (collagenous or lymphocytic colitis). NSAIDs, PPIs, and smoking are risk factors; budesonide is effective treatment.

Mesenteric Ischemia

Mesenteric ischemia is inadequate blood supply to the small intestine, causing severe abdominal pain out of proportion to physical findings. Acute mesenteric ischemia is a surgical emergency; chronic forms cause postprandial pain and weight loss.

Mast Cell Activation Syndrome

MCAS involves recurrent episodes of mast cell mediator release causing allergic-type symptoms (flushing, urticaria, hypotension, GI symptoms, anaphylaxis) without consistent triggers. Antihistamines and mast cell stabilizers are the foundation of treatment.

Giardiasis

Giardiasis is a common intestinal infection caused by the protozoan parasite Giardia lamblia, transmitted through contaminated water or food. It presents with chronic diarrhoea, bloating, and malabsorption, and is treated with metronidazole or tinidazole.

Strongyloidiasis

Strongyloidiasis is caused by Strongyloides stercoralis, a soil-transmitted nematode capable of autoinfection and chronic persistence for decades. In immunocompromised patients, hyperinfection syndrome can be life-threatening. Ivermectin is the treatment of choice.

Food Poisoning

Food poisoning is an illness caused by consuming contaminated food or water. Symptoms typically begin within hours to days of exposure and range from mild discomfort to severe dehydration.

Lactose Intolerance

Lactose intolerance is the inability to fully digest lactose due to insufficient lactase enzyme production. It causes digestive symptoms after dairy consumption but is manageable.

Salmonella Infection

Salmonellosis is a common bacterial food poisoning caused by Salmonella bacteria. It typically causes diarrhea, fever, and stomach cramps beginning 12-72 hours after infection.

Diverticulitis

Diverticulitis occurs when small pouches (diverticula) that form in the digestive tract become inflamed or infected. It causes abdominal pain and can lead to serious complications.