achlorhydria

Achlorhydria
Classification and external resources
Hydrogen chloride (major component of gastric acid)
ICD-10	K31.8
ICD-9	536.0
DiseasesDB	29513
eMedicine	med/18
MeSH	D000126

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 can cause symptoms similar to gastroesophageal reflux disease, and impairs protein digestion by inhibiting the activation of the enzyme pepsin, whose activation is dependent upon a low gastric pH. Furthermore, 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.^[1]
• A symptom of pernicious anemia, atrophic gastritis, VIPomas or of stomach cancer.
• Radiation therapy involving the stomach.
• Gastric Bypass procedures such a Duodenal Switch and RNY, where the largest acid producing parts of the stomach are either removed, or blinded.
• VIPoma (vasoactive intestinal peptide) a neuroendocrine tumor of the pancreas.

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 of symptoms. Many health practitioners recommend meal-time supplementation with Betaine Hydrochloride to increase gastric acidity and allow for proper digestion. Supplementation with minerals and vitamins like vitamin B12 (which is poorly absorbed in the absence of intrinsic factor) is usually recommended to compensate for malabsorption of nutrients, and foods with high microbial loads are usually avoided. Because the acidity of the stomach is a primary defense against infection of the gastrointestinal tract, antifungals and antibiotics may be needed to treat recurring infections.

Prognosis

Little is known on the prognosis of achlorhydria, although there have been reports of an increased risk of gastric cancer.^[2]

References

1. ^ El-Omar EM, Oien K, El-Nujumi A, et al (1997). "Helicobacter pylori infection and chronic gastric acid hyposecretion". Gastroenterology 113 (1): 15–24. doi:10.1016/S0016-5085(97)70075-1. PMID 9207257. 
2. ^ Svendsen JH, Dahl C, Svendsen LB, Christiansen PM (1986). "Gastric cancer risk in achlorhydric patients. A long-term follow-up study". Scand. J. Gastroenterol. 21 (1): 16–20. doi:10.3109/00365528609034615. PMID 3952447. 

See also

• Hyperchlorhydria
• Isopropamide
• Fundic gland polyposis