Explosive or severe diarrhea is diarrhea in overdrive. The contractions of your bowels that help you pass feces become stronger and more forceful. Your rectum fills with more volume than it can contain. Often, large amounts of gas accompany severe diarrhea. This increases the ejection and loudness of the bowel movement.

Diarrhea is defined as bowel movements of a more liquid consistency, or an increase in the number or volume of bowel movements. The World Health Organization (WHO) is more specific, defining diarrhea as three or more loose or liquid stools a day.

Approximately 75 percent of your stool is made of water. The other 25 percent is a combination of:

• undigested carbohydrates
• fiber
• protein
• fat
• mucus
• intestinal secretions

As feces travel through your digestive system, fluids and electrolytes are added to their content. Normally, your large intestine absorbs the excess fluid.

When you have diarrhea, though, digestion speeds up. Either the large intestine isn’t able to absorb the rush of fluid or more than the usual amount of fluids and electrolytes are secreted during digestion.

Diarrhea is a symptom that occurs with a number of conditions. The most common causes for severe diarrhea include:

Bacterial and viral infection

Bacteria that cause diarrhea-producing infections include salmonella and E. coli. Contaminated food and fluids are common sources of bacterial infections.

Rotavirus, norovirus, and other kinds of viral gastroenteritis, commonly referred to as “stomach flu,” are among the viruses that can cause explosive diarrhea.

Anyone can get these viruses. But they’re especially common among school-age children. And they’re common in hospitals and nursing homes, and on cruise ships.

Parasitic infection

Parasites like Giardia lamblia and cryptosporidium can cause severe diarrhea, particularly in people with weakened immune systems. As with viral and bacterial causes, these parasites are spread when there’s direct or indirect contact between feces and the mouth.

These parasites are found in contaminated drinking water, recreational waters, and food. Day care centers, where caregivers may not wash their hands well enough after changing diapers, are particularly vulnerable to outbreaks.

Diseases of the bowel

Diarrhea is a common problem for people who have an inflammatory bowel disease (IBD), Crohn’s disease or ulcerative colitis, or celiac disease.

Medications

Many medications can cause diarrhea. Antibiotics, certain medications used to treat heartburn and acid reflux, and chemotherapy drugs are frequent culprits.

Allergies or food intolerance

Diarrhea often occurs when you are allergic to, or have an intolerance of, certain foods, like the lactose found in dairy products.

Explosive diarrhea is usually short-lived. But there are complications that require medical care. These include:

Dehydration

Loss of fluids from diarrhea can cause dehydration. This is a particular concern in infants and children, older adults, and people with compromised immune systems.

An infant can become severely dehydrated within 24 hours.

Chronic diarrhea

If you have diarrhea for more than four weeks, it’s considered chronic. Your doctor will advise testing to determine the cause of the condition so it can be treated.

Hemolytic uremic syndrome

Hemolytic uremic syndrome (HUS) is a rare complication of E. coli infections. It occurs most often in children, though adults, particularly older adults, can get it, too.

HUS can cause life-threatening kidney failure if not treated promptly. With treatment, most people fully recover from the condition.

Symptoms of HUS include:

• severe diarrhea, and stools that may be bloody
• fever
• abdominal pain
• vomiting
• decreased urination
• bruising

Diarrhea is common. It’s estimated that adults in the United States experience 99 million episodes of diarrhea each year. Some people are at greater risk and include:

• children and adults who are exposed to feces, especially those who are involved in changing diapers
• people who travel to developing countries, particularly in tropical regions
• people taking certain medications, including antibiotics and medications used to treat heartburn
• people who have bowel disease

Diarrhea normally clears up within a few days without treatment. But you should see your doctor if you have the following symptoms:

• diarrhea lasting longer than two days or 24 hours in a child
• signs of dehydration, including excessive thirst, dry mouth, reduced urination, or dizziness
• blood or pus in your stool, or stool that’s black in color
• a fever of 101.5 °F (38.6 °C) or greater in an adult, or 100.4 °F (38 °C) or higher in a child
• severe abdominal or rectal pain
• diarrhea at night

Your doctor will ask questions about your symptoms, including:

• how long you’ve had diarrhea
• if your stools are black and tarry, or contain blood or pus
• other symptoms you’re experiencing
• medications you’re taking

You doctor will also ask about any clues you may have as to the cause of the diarrhea. Clues could be a food or fluid you suspect may have something to do with your illness, travel to a developing country, or a day of swimming in a lake

After providing these details, your doctor may:

• do a physical examination
• test your stool
• order blood tests

In many cases, treatment will involve managing your symptoms while you wait for the diarrhea to pass. The primary treatment for severe diarrhea is to replace fluids and electrolytes. Electrolytes are the minerals in your body fluid that conduct the electricity your body needs to function.

Drink more fluids, like water, and juice, or broths. Oral hydration solutions, such as Pedialyte, are formulated specifically for infants and children, and contain important electrolytes. These solutions are also available for adults. Find a great selection here.

You can use over-the-counter (OTC) anti-diarrheal medications if your stool isn’t black or bloody, and you don’t have a fever. These symptoms indicate you may have a bacterial infection or parasites, which can be made worse by antidiarrheal medications.

OTC medications should not be given to children under the age of two unless approved by a doctor. If your infection is bacterial, your doctor may prescribe antibiotics.