Achlorhydria and hypochlorhydria are states where the production of hydrochloric acid in gastric secretions of the stomach is absent or low, respectively. Achlorhydria is commonly a complication of some other disease, such as chronic Helicobacter pylori infection or autoimmune pernicious anemia, as well as a possible side effect of long-term use of proton pump inhibitors.

Complications of achlorhydria most frequently include small intestinal bacterial overgrowth and the nutritional deficiencies that can result from it. Rarely, achlorhydria may contribute to formation of gastric cancers or gastric carcinoid tumors.

  • abdominal discomfort
  • early satiety
  • weight loss
  • diarrhea
  • constipation
  • abdominal bloating
  • anemia
  • stomach infection
  • malabsorption of food
  • carcinoma of stomach

Since acidic pH facilitates iron absorption, achlorhydric patients often develop iron deficiency anemia.

Bacterial overgrowth, the most frequent complication of achlorhydria, can cause micronutrient deficiencies such as B12 deficiency and other nutrient deficiencies that result in various clinical neurological manifestations, including visual changes, paresthesias, ataxia, limb weakness, gait disturbance, memory defects, hallucinations and personality and mood changes. Nutritional deficiencies are the most common complication of achlorhydria.

Causes

  • The slowing of the body's basal metabolic rate is associated with hypothyroidism.
  • Pernicious anemia 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).
  • Of these, proton pump inhibitors have the most direct and potent known effect.
  • A symptom of atrophic gastritis or of stomach cancer.
  • Radiation therapy involving the stomach.
  • Gastric bypass procedures such as a duodenal switch and RNY, where the largest acid-producing parts of the stomach are either removed or blinded.
  • VIPomas (vasoactive intestinal peptides) and somatostatinomas are both islet cell tumors of the pancreas.
  • Pellagra, caused by niacin deficiency.
  • Chloride, sodium, potassium, zinc, and/or iodine deficiency, as these elements are needed to produce adequate levels of stomach acid (HCl).
  • Sjögren's syndrome, an autoimmune disorder that destroys many of the body's moisture-producing enzymes.
  • Ménétrier's disease, characterized by hyperplasia of mucous cells in the stomach, also causing excess protein loss, leading to hypoalbuminemia (presents with abdominal pain and edema).
  • Cholera The incidence increases to around 12% in populations over 80 years old. An absence of hydrochloric acid increases with advancing age. A lack of hydrochloric acid produced by the stomach is one of the most common age-related causes of a harmed digestive system.

Among men and women, 27% experience a varying degree of achlorhydria. US researchers found that over 30% of women and men over the age of 60 have little to no acid secretion in the stomach. Additionally, 40% of postmenopausal women have shown to have no basal gastric acid secretion in the stomach, with 39.8% occurring in females 80 to 89 years old. Autoimmune conditions can often be managed with various treatments; however, little is known about how or if these treatments effect achlorhydria.

Long-term usage of medications or drugs

Extended use of antacids, antibiotics, and other drugs can contribute to hypochlorhydria. Proton pump inhibitors (PPIs) are very commonly used to temporarily relieve symptoms and conditions such as gastroesophageal reflux and peptic ulcers.

The "Heidelberg test" is an alternative way to measure stomach acid and diagnose hypochlorhydria/achlorhydria.

A check can exclude deficiencies in iron, calcium, prothrombin time, vitamin B-12, vitamin D, and thiamine. Complete blood count with indices and peripheral smears can be examined to exclude anemia. Elevation of serum folate is suggestive of small bowel bacterial overgrowth. Bacterial folate can be absorbed into the circulation.

Once achlorhydria is confirmed, a hydrogen breath test can check for bacterial overgrowth.

Treatment

Treatment focuses on addressing the underlying cause of symptoms, as well as correction of any nutritional deficiencies, such as vitamin B-12 deficiency and the pernicious anemia that typically accompanies it. Patients with known or suspected H. pylori infection should be followed and endoscopically evaluated over time, due to the risk of recurrence as well as potential gastric malignancy.

Achlorhydria resulting from long-term proton-pump inhibitor (PPI) use may be treated by dose reduction or withdrawal of the PPI. Prudent use of antibacterials now calls for an antimicrobial stewardship policy to manage antibiotic resistance.

See also

  • Atrophic gastritis
  • Fundic gland polyposis
  • Hyperchlorhydria
  • Isopropamide

References