Diarrhea and a Host of Symptoms: What's the Cause?

When diarrhea is accompanied by a laundry list of additional symptoms — weight loss, fatigue, weakness and stomach pain — it can be extremely debilitating. But what can trigger such discomforting symptoms? As it turns out, there's no one answer.

​Read more:​ 5 Possible Causes of Diarrhea That Lasts for 5 Days or More

Several very different health conditions could be responsible for diarrhea and a host of other symptoms. These include:

​Hepatitis A.​ The viral liver disease hepatitis A is one possible diagnosis stemming from this array of symptoms. According to Cedars Sinai, because it is highly contagious and typically spread by person-to-person contact, you're most likely to contract hepatitis A by touching contaminated objects, consuming infected food or drinks or having sex with an infected partner.

While symptoms can vary in type and severity, you may experience fatigue, loss of appetite, upset stomach, vomiting or diarrhea and belly pain, among other symptoms.

​West Nile virus.​ According to the Centers for Disease Control and Prevention (CDC), the West Nile virus, which is spread by mosquito bites, is another potential cause. Though most people never develop symptoms, about a fifth of people infected with this virus develop fever, headaches, diarrhea, vomiting and body aches, the CDC notes. They usually make a full recovery, though fatigue and weakness can linger for several weeks or even months.

Of those infected, the CDC says, about 1 in 150 develops potentially fatal nervous system complications, such as encephalitis (brain inflammation) or meningitis (spinal cord and brain membrane inflammation).

​Inflammatory bowel disease​ (IBD). This is another condition that could cause you a mix of severe diarrhea, fatigue, weight loss and abdominal pain, according to Mayo Clinic. IBD involves chronic inflammation of the digestive tract, and it includes ulcerative colitis and Crohn's disease.

Here, too, more than one possible cause exists, such as:

​C. coli infection.​ Among possible bacterial causes, CDC experts point to infections caused by the spiral-shaped campylobacteraceae family of microbes, including so-called C. coli infections.

You could contract such infections by eating contaminated foods, including contaminated milk or water and undercooked poultry. Symptoms can include diarrhea (often bloody), stomach pain, fever and, sometimes, nausea or vomiting, with dehydration occurring in more severe cases. Symptoms generally develop within 10 days of initial infection.

Such infections are a major cause of bacterial disease the world over, the CDC says, accounting for 96 million cases in 2010 alone, with an estimated 1.3 million cases in the United States each year.

​Salmonella infection.​ Diarrhea, fever and stomach cramps — sometimes with nausea, vomiting or headache — also can result from the bacterial infection salmonella, CDC says. Because the bacteria live in the intestines of both animals and humans, infection can result from contact with infected animals and their surroundings, as well from consumption of contaminated food or water, CDC explains,

Whether brought on by bacteria, viruses, parasites or their toxins, food poisoning is a phenomenon often at the root of diarrhea. According to the Mayo Clinic, cross-contamination is usually the culprit, and if you consume raw or ready-to-eat uncooked foods like produce, you could be at risk.

With food poisoning, it's often hard to pinpoint the exact cause, given that contamination can occur at any juncture, from harvesting to storage to shipping to food prep, the Mayo Clinic adds. What isn't difficult, however, is identifying your telltale symptoms.

"Food poisoning usually takes about six to eight hours after eating the contaminated food to result in diarrhea and vomiting, and sometimes fever," explains Lona Sandon, PhD, RDN, a dietitian/nutritionist and associate professor in the Department of Clinical Nutrition at the University of Texas Southwestern Medical Center at Dallas. "But when it happens, you know it because this is your body's way of getting the offending pathogen out as quickly as possible."

That point is seconded by St. Louis-based dietitian Connie Diekman, RD, MEd, a food and nutritionist consultant and former president of the Academy of Nutrition and Dietetics.

"Since much of the immune system is found in the intestinal tract, the intestines work to try to eliminate the bacteria," she says. And that explains the diarrhea, she says, because "with diarrhea, we get rid of the bacteria."

The problem? "With it go other nutrients and, of course, fluids," Diekman points out. And that raises the risk for dehydration, and the severe fatigue and weakness that can ensue. "Which is why consuming fluids is so important."

​Read more:​ What Really Happens to Your Body When You're Dehydrated