diarrhea specialist tests overview

Overview

This overview covers the tests a specialist (like a gastroenterologist) might use to find the cause of long-lasting or severe diarrhea. Diarrhea means loose, watery bowel movements. When it doesn't go away on its own, your doctor may recommend specialist tests to look for underlying problems.

Chronic diarrhea is fairly common. It affects about 1 in 20 adults at some point. Specialist tests are only needed when the cause isn't clear or symptoms are severe.

It can affect people of any age, but it is more common in adults over 60 and in people with conditions like irritable bowel syndrome (IBS) or inflammatory bowel disease (IBD).

Symptoms

Common symptoms

• Loose, watery stools three or more times a day for weeks
• Urgent need to use the bathroom
• Cramping or belly pain
• Bloating or gas

Symptoms in children

• Frequent, watery bowel movements
• Signs of dehydration: dry mouth, fewer wet diapers, crying without tears
• Refusing to drink or eat
• Fussiness or unusual sleepiness

Symptoms in older adults

• Diarrhea that lasts more than a few days
• Feeling very weak or dizzy when standing
• Weight loss without trying
• Changes in thinking or confusion

Causes

Main causes

• Infections from bacteria, viruses, or parasites
• Food intolerances, such as lactose or gluten sensitivity
• Inflammatory bowel disease (Crohn's disease or ulcerative colitis)
• Irritable bowel syndrome (IBS)
• Side effects of some medications (like antibiotics or laxatives)

Risk factors

• Recent travel to areas with poor sanitation
• Weakened immune system (from illness or medications)
• Family history of IBD or celiac disease
• Taking antibiotics in the past few months
• Drinking untreated water or eating undercooked food

When to see a doctor

See a doctor urgently if:

• If you have diarrhea and signs of dehydration that don't improve
• If you see blood in your stool
• If you have severe pain or high fever

Book a routine appointment if:

• If diarrhea lasts more than 3 days for adults or more than 2 days for children
• If you have unexplained weight loss
• If you have a chronic condition like diabetes or IBD

Diagnosis

A specialist will start by asking about your symptoms, medical history, and any recent travel or food. They may then order tests to narrow down the cause.

Tests that may be done

• Stool test: checks for bacteria, parasites, or blood
• Blood test: looks for signs of infection, inflammation, or celiac disease
• Hydrogen breath test: helps find lactose intolerance or bacterial overgrowth in the gut
• Colonoscopy or flexible sigmoidoscopy: a camera tube to look inside the large intestine
• Imaging (CT scan or MRI): detailed pictures of the bowel

What to expect at your appointment

Most tests are simple and painless. For a colonoscopy, you'll need to drink a special liquid the day before to clear your bowel. The doctor will explain each test and what you need to do to prepare.

Treatment

Treatment depends on the cause. Many cases of chronic diarrhea improve with diet changes, medications, or treating the underlying condition. Your doctor will create a plan tailored to you.

Self-care at home

• Drink plenty of fluids to avoid dehydration (water, clear broths, oral rehydration solutions)
• Eat bland foods like bananas, rice, applesauce, toast (BRAT diet)
• Avoid alcohol, caffeine, dairy, and fatty or spicy foods until symptoms improve
• Rest and wash hands often to prevent spreading infections

Medical treatments

Doctors may prescribe antibiotics for bacterial infections, anti-inflammatory drugs for IBD, or medications to slow bowel movements. Always follow your doctor's advice and never take medicine for diarrhea without checking with them first.

When is surgery considered?

Surgery is rarely needed for diarrhea. It may be considered if the cause is a structural problem like a blockage or damage from IBD that doesn't respond to other treatments.

Living with this condition

If you have chronic diarrhea, plan ahead: know where bathrooms are, carry a change of clothes and wipes, and talk to your employer or school about your condition.

Lifestyle tips

• Keep a food diary to identify triggers
• Stay hydrated throughout the day
• Avoid foods that make symptoms worse
• Consider stress management techniques, as stress can worsen diarrhea

Diet and exercise

A balanced diet with plenty of fibre may help, but if you have a food intolerance, you may need to avoid certain foods. Gentle exercise like walking can improve digestion, but listen to your body and rest when needed.

Mental health and emotional wellbeing

Chronic diarrhea can be embarrassing and stressful. It may affect your social life or mood. It's okay to ask for help – you're not alone.

Prevention

Not all cases can be prevented, but you can lower your risk by washing hands well, drinking safe water, cooking food thoroughly, and avoiding foods you know you cannot tolerate.

Complications

If left untreated

• Dehydration (loss of fluids and salts)
• Malnutrition (not getting enough nutrients)
• Weight loss
• Kidney problems from dehydration

Long-term outlook

With the right diagnosis and treatment, most people with chronic diarrhea get better. Even long-term conditions like IBD can be managed so that symptoms are controlled. You can live a full, active life.

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