Achlorhydria

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Overview
Achlorhydria and hypochlorhydria refer to states where the production of gastric acid in the stomach is absent or low, respectively. It is associated with various other medical problems.

Signs and symptoms
The decreased acid level itself causes few symptoms, but low acid levels in the stomach are linked with bacterial overgrowth (as the stomach does not kill microbes normally present in food), which can manifest as diarrhoea or decreased absorption of nutrients or vitamins. Risk of particular infections, such as Vibrio vulnificus (commonly from seafood) is increased.

Causes

 * Autoimmune disorders where there is antibody production against parietal cells which normally produce gastric acid.
 * The use of antacids or drugs that decrease gastric acid production (such as H2-receptor antagonists) or transport (such as proton pump inhibitors).
 * A symptom of rare diseases such as mucolipidosis (type IV).
 * A symptom of Helicobacter pylori infection which neutralizes and decreases secretion of gastric acid to aid its survival in the stomach.
 * A symptom of pernicious anemia, atrophic gastritis, VIPomas or of stomach cancer.
 * Radiation therapy involving the stomach.

Diagnosis
90% of all patients with achlorhydria have detectable antibodies against the H+/K+ ATP-ase proton pump. The diagnosis is made if the gastric pH remains high (>4.0) despite maximum pentagastrin stimulation. High gastrin levels are often detected.

Treatment
Treatment focuses on addressing the underlying cause, supplementation of vitamins like vitamin B12 (which is poorly absorbed in the absence of intrinsic factor) in autoimmune disorders, and avoiding foods that may have a high microbial load, and in some cases the use of Betaine hydrochloride has been successful. Usually little or no treatment is necessary. Antibiotics may be needed in significant bacterial overgrowth.

Prognosis
Little is known on the prognosis of achlorhydria, although there have been reports of an increased risk of gastric cancer.