Achlorhydria

Overview

Achlorhydria is the absence of hydrochloric acid (HCl) secretion in the stomach. It may be partial (hypochlorhydria) or complete. Gastric acid is essential for digestion, absorption of nutrients (iron, vitamin B12, calcium), and protection against pathogens.

Causes include:

• Chronic atrophic gastritis (often autoimmune).

• Helicobacter pylori infection.

• Long-term proton pump inhibitor (PPI) therapy.

• Pernicious anemia (autoimmune destruction of parietal cells).

• Gastric surgery (gastrectomy, vagotomy).

• Zollinger–Ellison syndrome treatment (after aggressive acid suppression).

Complications: iron deficiency anemia, vitamin B12 deficiency, bacterial overgrowth, gastric neoplasia.

---

Treatment Options

1. Treat Underlying Cause

• H. pylori eradication:

  • Triple therapy (14 days):

    • Clarithromycin 500 mg PO BID + Amoxicillin 1 g PO BID (or metronidazole 500 mg BID if penicillin-allergic) + PPI (omeprazole 20 mg PO BID).

• Autoimmune gastritis/pernicious anemia:

  • Vitamin B12 replacement:

    • Cyanocobalamin 1000 mcg IM monthly or oral 1000–2000 mcg daily.

• Drug-induced (long-term PPI use):

  • Reduce or discontinue PPI if possible; switch to H2 blocker if needed.

• Post-surgical: nutritional monitoring and supplementation.

---

2. Nutritional Support

• Iron supplementation:

  • Ferrous sulfate 325 mg PO TID with vitamin C to enhance absorption.

• Calcium and vitamin D supplementation to prevent bone loss.

• Folic acid 1 mg PO daily if deficiency suspected.

---

3. Symptomatic / Supportive Measures

• Digestive enzyme supplementation (e.g., pancreatic enzyme capsules) if maldigestion present.

• Probiotics to reduce risk of small intestinal bacterial overgrowth (SIBO).

• Dietary modifications:

  • Frequent, small meals.

  • Avoid foods difficult to digest (excessive fats, processed meats).

---

Monitoring & Follow-Up

• CBC, iron studies, vitamin B12, folate every 6–12 months.

• Endoscopy with biopsy in chronic atrophic gastritis (risk of gastric carcinoma).

• Bone density monitoring in long-standing achlorhydria.

---

Key Notes

• Achlorhydria is a clinical sign, not a standalone disease → always search for the cause.

• Long-term achlorhydria increases risk of gastric adenocarcinoma and neuroendocrine tumors.

• Lifelong nutritional monitoring and supplementation are often required.