The medical field of gastroenterology is the study of the diseases of the human digestive system. Among the organs involved, the liver — in part because it is responsible for removing toxic substances from the omnivorous human diet — is most prone to dysfunction. Hepatology, the study of the diseases of the liver, is a sub-specialty. Whether as an academic discipline at a medical school or in a clinical wing of a private hospital, the two fields are usually combined and abbreviated gastro hepatology.
For most people, the stomach and small intestine are the first organs that come to mind along the digestive tract. The most serious disease to affect these organs is gastroenteritis. Most often caused by viral contamination of food and water, and commonly misnamed “stomach flu,” the inflamed organs cause diarrhea and dehydration. Worldwide estimates from the year 2000 attributed 1.5 million deaths to gastroenteritis, which has long been a leading cause of infant mortality.
Potentially fatal diseases also afflict other less familiar, and more task-specific, gastric organs. Gastro hepatology recognizes that digestion is accomplished by an interconnected system of several organs, and that a diseased link can cause systemic digestive failure. Each organ can be afflicted by external agents, such a microorganisms and toxic chemical compounds. There are unusual hereditary diseases. Complications can arise from both natural organic processes and unnatural cancerous malformations.
The pancreas is both a digestive and endocrine organ. It produces insulin and other hormones that regulate the concentration of sugar in the bloodstream. Type 1 diabetes is a pancreatic disease. The pancreas also produces and secretes digestive enzymes into the small intestine through a tubular duct; this is critical to the final breakdown of carbohydrates, proteins and fats.
The most common serious affliction of the pancreas as a digestive organ is sudden inflammation. There are various causes, including an allergic reaction to a scorpion sting and gallstones. Gallstones are small pebbles of hardened bile that form in the gallbladder, another gastric organ.
Bile, produced by the liver, is stored in the gallbladder. This enzymatic liquid is released into the digestive tract through the biliary tree and bile duct to break apart ingested fats. Gallstones are not uncommon, are usually benign, and can pass intact through the digestive system. If they become too large, however, and obstruct the biliary tree or any of its tubular branches, serious harm will be inflicted on the gallbladder, the pancreas, or the liver.
Gastro hepatology focuses most of its effort on the liver, a large organ critical to human life. The live, for example, is the principle manufacturer of proteins, the so-called “building blocks of life.” In a growing human fetus, the liver makes red blood cells; when bone marrow starts producing red blood cells, the liver switches to the task of destroying older red blood cells. It also produces the coagulants that enable blood to clot and damaged vessels to self-repair.
Relative to human digestion, an additional function of the liver is to recombine the digested components of carbohydrates to create glucose, the sugar that fuels the human body. Vitamins and minerals are stored in the liver. It also breaks down or neutralizes ingested foreign compounds such as alcohol, ammonia, drugs and toxins.
Among the most common liver afflictions handled by the field of gastro hepatology are hepatitis, alcoholism-induced cirrhosis, and damage caused by drugs. Culprits can include abuse of illicit drugs, and unexpected metabolites resulting from the interaction of two incompatible therapeutic drugs. Even toxic levels of common over-the-counter pain relievers can cause liver damage.
There is one particularly bright beacon of medical hope in the field of gastro hepatology. The liver is the only internal human organ capable of regeneration. With just an estimated 20 percent of its tissue and a few critical structures intact, it can in time rebuild itself to nearly 100 percent of its original condition. This feature is advancing the treatment of liver diseases with increasingly successful donor transplant procedures.
