A nurse is conducting an assessment on a 70-year-old client who reports progressive fatigue and weakness 3 years after undergoing a total gastrectomy. Which laboratory finding should the nurse anticipate as most characteristic of the expected nutritional deficiency?

A client who is 70 years old and underwent a total gastrectomy 3 years ago now presents with progressive fatigue and weakness. To answer this question correctly, you must link the surgical history directly to the pathophysiology of a specific nutritional deficiency. The stomach's parietal cells produce intrinsic factor (IF), a protein essential for the absorption of vitamin B12 (cobalamin) in the terminal ileum. A total gastrectomy permanently removes the source of intrinsic factor, making it impossible for the body to absorb vitamin B12 from dietary sources or oral supplements. While the liver typically stores several years' worth of vitamin B12, these reserves become depleted over time, which explains the latency of symptoms. The progressive fatigue and weakness reported by the client are classic early systemic manifestations of this developing deficiency.

The connection between total gastrectomy and vitamin B12 deficiency is absolute and irreversible. Without intrinsic factor, vitamin B12 cannot bind to receptors in the ileum for absorption. This leads to a depletion of hepatic stores, which can sustain the body for 1 to 5 years or longer. The case report by Cho et al. highlights this latency, documenting a case of subacute combined degeneration (SCD) that developed 8 years post-gastrectomy, emphasizing that neurological complications can be significantly delayed ^[1]. The deficiency impairs two critical biochemical pathways: the conversion of methylmalonyl-CoA to succinyl-CoA (affecting myelin synthesis) and the conversion of homocysteine to methionine (affecting DNA synthesis and red blood cell maturation). The neurological damage results from the incorporation of abnormal fatty acids into neuronal lipids, leading to demyelination, while the hematologic effects produce megaloblastic anemia, which explains the client’s fatigue and weakness.

The question asks for the most characteristic laboratory finding related to the expected deficiency. While a lab value is not explicitly listed with a number, the options represent clusters of clinical signs that directly reflect underlying laboratory abnormalities.

• Option 1: Petechiae and easy bruising. These signs suggest thrombocytopenia, which is more characteristic of bone marrow suppression, platelet disorders, or liver disease. While severe megaloblastic anemia can cause pancytopenia, this is not the most specific or primary manifestation of vitamin B12 deficiency.


• Option 2: Night blindness and dry skin. This cluster is pathognomonic for vitamin A deficiency. Vitamin A is fat-soluble, and its absorption can be affected by gastric surgery, but the progressive neurological and mucosal symptoms of B12 deficiency are more prominent and specific in this context.


• Option 3: Muscle cramps and tetany. These are classic signs of hypocalcemia, often resulting from hypoparathyroidism or vitamin D deficiency. While calcium absorption can be altered post-gastrectomy, this presentation does not align with the primary defect in intrinsic factor production.


• Option 4: Glossitis and neurological symptoms. This is the hallmark presentation of vitamin B12 deficiency. Glossitis (a smooth, beefy-red, painful tongue) results from the disruption of rapidly dividing epithelial cells due to impaired DNA synthesis. The neurological symptoms, collectively termed subacute combined degeneration (SCD) of the spinal cord, involve demyelination of the dorsal columns (causing paresthesia and loss of proprioception) and lateral corticospinal tracts (causing weakness and spasticity) ^[1]. The systematic review on functional B12 deficiency confirms that neurological complications are a primary and severe consequence of this deficiency .

The case report by Cho et al. is particularly instructive for NCLEX preparation because it underscores the need for lifelong vigilance. Their report of an 8-year latency period before the onset of SCD in a post-gastrectomy patient demonstrates that the absence of early symptoms does not guarantee safety ^[1]. The study by Moreno-Mirón et al. further classifies post-surgical malabsorption as a distinct and critical etiology of vitamin B12 deficiency, reinforcing that patients with this history require permanent parenteral replacement therapy . The neurological symptoms, including paresthesia, ataxia, and cognitive changes, can become irreversible if treatment is delayed, making early recognition of glossitis and subtle neurological signs a critical nursing responsibility.