Sprue is a medical term used to describe a group of chronic digestive conditions characterized by damage to the small intestine, which leads to a severe inability to absorb nutrients, a process known as malabsorption. This disruption results in a range of systemic health problems stemming from long-term nutritional deficiencies.
Defining Sprue and its Types
The term “sprue” primarily refers to two distinct conditions that cause similar damage to the small intestine lining. These conditions are differentiated by their cause and the geographic location where they are typically acquired.
Celiac sprue, which is the historical name for Celiac Disease, is an autoimmune disorder triggered by the ingestion of gluten, a protein found in wheat, barley, and rye. In genetically predisposed individuals, consuming gluten provokes an immune response that mistakenly attacks the small intestinal lining. This reaction leads to the flattening and destruction of the finger-like projections called villi, which are responsible for absorbing nutrients.
Tropical sprue is a separate condition that causes similar damage to the small intestinal villi but occurs exclusively in tropical or subtropical regions, such as the Caribbean, Southern India, and Southeast Asia. While the exact cause remains unknown, it is thought to be an acquired disorder resulting from a chronic infection by certain types of bacteria. Unlike Celiac sprue, tropical sprue is not an autoimmune reaction to gluten and is commonly treated with a combination of antibiotics and nutritional supplements.
Common Symptoms and Health Consequences
Malabsorption first manifests in the digestive tract with a set of characteristic gastrointestinal symptoms. Patients commonly experience chronic diarrhea, along with abdominal cramping, bloating, and excessive gas.
A defining feature of malabsorption is steatorrhea, characterized by stools that are pale, bulky, foul-smelling, and often appear greasy because they contain unabsorbed fat. Over time, the lack of nutrient absorption leads to severe systemic health consequences. Weight loss and chronic fatigue are common due to the inability to absorb macronutrients like fats and carbohydrates. The malabsorption of specific micronutrients, such as iron and vitamin B12, often results in anemia. Furthermore, a lack of calcium and Vitamin D absorption can lead to osteomalacia or osteoporosis, weakening the bones and increasing fracture risk.
Diagnosis and Management Approaches
Diagnosing sprue involves a combination of blood tests and a definitive procedure to examine the small intestine. For Celiac sprue, blood tests look for specific autoantibodies, most commonly the tissue transglutaminase IgA (tTG-IgA) antibody. Because a small percentage of people with Celiac disease are IgA deficient, total serum IgA levels are often checked to ensure the antibody test is accurate.
The conclusive step for diagnosing both Celiac and Tropical sprue is an upper gastrointestinal endoscopy with a small intestine biopsy. The biopsy allows doctors to microscopically examine the intestinal lining for villous atrophy, which is the flattening of the villi that confirms severe damage and malabsorption. For Tropical sprue, blood tests confirming deficiencies in folic acid and vitamin B12, combined with a history of travel to an endemic region, strongly support the diagnosis.
For Celiac sprue, the treatment involves a strict, lifelong exclusion of gluten from the diet, which allows the small intestine to heal and the villi to regenerate. Compliance with the gluten-free diet is paramount for resolving symptoms and preventing long-term complications. Tropical sprue is typically managed with a prolonged course of antibiotics, such as tetracycline, often lasting several months to eliminate the presumed bacterial infection. Additionally, patients with Tropical sprue require supplements, particularly high doses of folic acid and vitamin B12, to correct the severe deficiencies caused by the disease.