# Situation: A 58-year-old woman had a total gastrectomy for gastric adenocarcinoma 10 days ago. She now eats small meals and is preparing for discharge. She has no diabetes. Because of the type of operation she had, which replacement will she need for the rest of her life?

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> subject: Nursing Practice IV — Care of Clients with Problems in Nutrition and Gastrointestinal, Metabolism and Endocrine, Perception and Coordination

## 문제

Situation: A 58-year-old woman had a total gastrectomy for gastric adenocarcinoma 10 days ago. She now eats small meals and is preparing for discharge. She has no diabetes.

Because of the type of operation she had, which replacement will she need for the rest of her life?

## 보기

1. Folic acid tablets
2. Vitamin K injections
3. Potassium chloride tablets
4. Vitamin B12 injections **✔ 정답**

**정답: 4**

## 해설

The stomach's parietal cells make intrinsic factor, which is needed to absorb vitamin B12 in the ileum. After total gastrectomy, intrinsic factor is lost, so lifelong vitamin B12 is given by injection (or high-dose oral per prescriber), and iron, calcium, and vitamin D are monitored.

## 심화 해설

Core mechanism

The parietal cells of the gastric body normally produce intrinsic factor, a glycoprotein that binds dietary vitamin B12 and permits its absorption in the terminal ileum. A total gastrectomy removes all parietal cells, so intrinsic factor is permanently absent. Without it, vitamin B12 cannot be absorbed through the physiologic route, and deficiency develops over months to years as hepatic stores are depleted [1][2].

Because the loss of intrinsic factor is permanent, vitamin B12 replacement must continue for life. The classic replacement route is intramuscular injection, which bypasses the ileal absorptive defect entirely [1][3]. High-dose oral vitamin B12 has been studied as an alternative because approximately 1% of an oral dose can be absorbed by passive diffusion independent of intrinsic factor, but parenteral administration remains the standard clinical approach [1][3].

Why the other options are incorrect

Folic acid absorption occurs primarily in the proximal small intestine and does not require intrinsic factor. Total gastrectomy does not eliminate the folate absorptive surface, so routine lifelong folic acid tablets are not mandated by the operation itself. Vitamin K is a fat-soluble vitamin absorbed in the small intestine with bile salts; total gastrectomy does not remove the intestinal absorptive site, and vitamin K injections are not a standard lifelong requirement. Potassium chloride is an electrolyte supplement used for specific losses such as vomiting, diarrhea, or diuretic therapy; total gastrectomy does not create a permanent need for potassium replacement in the absence of ongoing losses.

Clinical timing and monitoring

Vitamin B12 deficiency does not appear immediately after surgery. Hepatic stores can sustain levels for months to years, which is why a patient may be discharged without symptoms yet still require scheduled supplementation [2][4]. Deficiency is defined in the cited studies as a serum vitamin B12 level below 200 pg/mL or an elevated urine methylmalonic acid above 3.8 mg/gCr [2]. Regular replacement intervals are associated with better maintenance of normal levels than irregular or symptom-driven dosing [2].

Watch out! Neurologic and psychiatric manifestations of B12 deficiency can emerge years after total gastrectomy, including subacute combined degeneration and acute mental status changes, even when hematologic abnormalities are mild or absent [4]. Key point! The need for vitamin B12 after total gastrectomy is lifelong and is not cured by dietary changes alone, because the absorptive defect is structural and permanent.

| Comparison | Total gastrectomy consequence | Replacement need |
| --- | --- | --- |
| Intrinsic factor | Permanently absent | Lifelong vitamin B12 injection or high-dose oral therapy |
| Iron absorption | Reduced due to rapid transit and decreased acid | Monitored; replaced only if deficiency develops |
| Calcium and vitamin D | Risk of malabsorption and bone loss | Monitored; supplemented as indicated |
| Folate | Absorption largely preserved | Not routinely required for life |

The priority for discharge planning after total gastrectomy is to establish a scheduled vitamin B12 replacement regimen. Intramuscular injection is the most widely used form because it does not depend on any gastrointestinal absorptive mechanism [1][2][3].References (research sources)

- [1]Oral vitamin B₁₂ after total gastrectomy for gastric cancer: mapping the evidence.Research articleRogaczewski P, Janiak M, Durślewicz J, Koper K, Borowczak J. (2026) · DOI: 10.1007/s10120-026-01745-8

- [2]Effect of Vitamin B12 Replacement Intervals on Clinical Symptoms and Laboratory Findings in Gastric Cancer Patients after Total Gastrectomy.Research articlePark SH, Eom SS, Lee H, Eom BW, Yoon HM, Kim YW (2023) · DOI: 10.3390/cancers15204938

- [3]Oral vitamin B12 replacement: an effective treatment for vitamin B12 deficiency after total gastrectomy in gastric cancer patients.Research articleKim HI, Hyung WJ, Song KJ, Choi SH, Kim CB, Noh SH (2011) · DOI: 10.1245/s10434-011-1764-6

- [4]Acute Mental Disorder Caused by Vitamin B12 Deficiency Eight Years After Total Gastrectomy.Research articleTsubaki T, Morikawa M, Goi T, Hirono Y (2024) · DOI: 10.7759/cureus.68507

## 임상 시나리오

Post-Total Gastrectomy Vitamin B12 ReplacementLifelong parenteral therapy after loss of intrinsic factor
Total gastrectomy permanently removes parietal cells, eliminating intrinsic factor production. Without intrinsic factor, dietary vitamin B12 cannot be absorbed in the terminal ileum, so deficiency develops over months to years as hepatic stores deplete.

Replacement must continue for life. The standard route is intramuscular injection, which bypasses the ileal absorptive defect entirely. High-dose oral vitamin B12 may be considered because approximately 1% of an oral dose is absorbed by passive diffusion independent of intrinsic factor, but parenteral administration remains the standard clinical approach.

Also monitor iron, calcium, and vitamin D levels after total gastrectomy, as these nutrients may require supplementation due to altered digestion and absorption.

CautionDo not rely on oral vitamin B12 as first-line therapy unless specifically prescribed; the passive diffusion route is unreliable for most patients. Assess for neurological symptoms of B12 deficiency, which may occur without significant anemia.

## 핵심 개념

- **Intrinsic factor** — A glycoprotein secreted by gastric parietal cells that binds vitamin B12 and enables its absorption in the terminal ileum.
- **Total gastrectomy** — Surgical removal of the entire stomach, resulting in permanent loss of parietal cells and intrinsic factor production.
- **Vitamin B12 deficiency** — Develops months to years after total gastrectomy as hepatic stores are depleted, causing megaloblastic anemia and neurological symptoms.
- **Parietal cells** — Cells in the gastric body that produce both hydrochloric acid and intrinsic factor.
- **Parenteral replacement** — Administration of a substance by injection, bypassing the gastrointestinal absorptive defect.

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