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Medical Mystery: What's causing weight loss, distended abdomen?

A middle-aged man came to Einstein Medical Center Philadelphia after enduring seven months of diarrhea and joint pain. He'd lost a great deal of weight, even though his diet was normal. A physical examination showed him to be severely debilitated, with muscle wasting and a markedly distended abdomen. Four liters of fluid were removed from his abdomen for therapeutic and diagnostic purposes.

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A middle-aged man came to Einstein Medical Center Philadelphia after enduring seven months of diarrhea and joint pain.

He'd lost a great deal of weight, even though his diet was normal. A physical examination showed him to be severely debilitated, with muscle wasting and a markedly distended abdomen. Four liters of fluid were removed from his abdomen for therapeutic and diagnostic purposes.

The most common causes of that kind of fluid accumulation - called ascites - are liver disease, kidney disease, and malignancy.

Alcohol abuse or hepatitis can also cause scarring of the liver that blocks blood flowing through it, creating pressure that forces fluid into the abdomen.

Certain types of kidney disease can lead to fluid overload, and cancer that spreads to the abdomen can cause lining cells to produce fluid in response to the irritation.

Laboratory tests revealed two clues - anemia and a low serum albumin, a protein in blood plasma - suggesting the problem could be any of those three conditions.

The albumin protein maintains the osmotic pressure that keeps the fluid within blood vessels rather than diffusing into tissues and pooling in the abdomen. A low value results when a diseased liver doesn't make enough albumin or from kidney disease, when albumin spills into the urine. Malnutrition from a malignancy can also cause anemia and low albumin production.

But other lab tests - involving liver enzymes and electrolytes and the kidney's waste products - indicated the liver and kidneys were functioning normally. Diagnostic imaging also showed a normal liver and kidney, and no evidence of abdominal cancer.

What, then, was causing this patient's symptoms?

The weight loss and chronic diarrhea suggested a possible malabsorption syndrome, in which the small intestine can't absorb fat and protein from food. Stool studies did reveal unabsorbed fat in the patient's intestines.

To confirm the diagnosis, doctors performed an upper endoscopy, in which a lighted, flexible tube is inserted through the mouth to examine the esophagus, stomach, and parts of the intestine.

Again, the study was normal.

But tissue samples were sent to the laboratory for further analysis. And that's where the mystery got more interesting.

Solution:

When Einstein pathologist Ronald Miick examined tissue from the small intestine, he noted it was filled with macrophages, a type of inflammatory cell that absorbs bacteria and cleans up debris. That suggested an infection.

Was it an atypical manifestation of mycobacteria, which causes tuberculosis but can cause other symptoms? Or was it histoplasmosis, an infection caused by breathing in spores of a fungus often found in soil with significant bird droppings?

It was neither.

Using special stains on the biopsy, Miick identified pink staining granules inside the inflammatory cells, confirming his suspicion of Whipple's disease.

These granules represented ingested remnants of Tropheryma whippelei, the bacterium that causes Whipple's disease. The disease is extremely rare; there are only 12 to 30 cases reported annually worldwide. Experts aren't sure how the disease is spread. It seems to be more common in farmers and others who toil outdoors and have frequent contact with soil and sewage wastewater.

Our case was particularly puzzling because fluid in the abdomen appears even more rarely - in only 5 percent of cases - making the diagnosis that much harder to make.

A subsequent physical examination revealed the patient had enlarged lymph nodes in the groin, which strengthened the diagnosis.

The infection is named for Dr. George Hoyt Whipple, who discovered it in 1907. Whipple's disease is a chronic disorder that involves multiple organs and often shows up in the intestine, causing a triad of symptoms: diarrhea, weight loss, and malabsorption.

However, digestive symptoms are often preceded for months or years by other symptoms, such as joint pain.

In retrospect, the patient's arthritis was an overlooked clue.

Without treatment, the bacterial condition is usually fatal because it is systemic and can involve almost all the organs, including the brain, heart, lungs, eyes, kidney, liver, spleen, lymph nodes, and bone marrow.

Within a month of being treated with antibiotics, the patient's diarrhea and joint pain resolved, and he regained a significant amount of weight. The months of suffering he'd endured came to an end.

Nancy Young is chair of pathology and laboratory medicine at Einstein Healthcare Network.