What is the plan of care for a patient with iron deficiency anemia, hyponatremia, and hyperkalemia?

Plan of Care for 72-Year-Old with Iron Deficiency Anemia, Hyponatremia, and Hyperkalemia

This patient requires immediate oral iron supplementation with ferrous sulfate 200 mg once daily, urgent investigation with upper endoscopy and colonoscopy to identify the source of blood loss, and concurrent management of the severe hyponatremia (sodium 128) and hyperkalemia (potassium 5.4) which take priority over the anemia due to their immediate life-threatening potential.

Immediate Priorities

Address Life-Threatening Electrolyte Abnormalities First

• The severe hyponatremia (128 mEq/L) and hyperkalemia (5.4 mEq/L) require urgent evaluation and correction before focusing solely on anemia management, as these can cause cardiac arrhythmias, seizures, and altered mental status.
• Determine if the patient is on medications causing these abnormalities (ACE inhibitors, ARBs, potassium-sparing diuretics, NSAIDs).
• The low creatinine (0.49) suggests possible malnutrition or muscle wasting, which may contribute to electrolyte disturbances.

Iron Deficiency Anemia Management

Initiate Oral Iron Supplementation

• Start ferrous sulfate 200 mg once daily in the morning on an empty stomach 1, 2.
• Add vitamin C 500 mg with each iron dose to enhance absorption 1.
• Alternate-day dosing (200 mg every other day) can be used if gastrointestinal side effects occur, as this maximizes fractional absorption while reducing side effects 1, 3.
• Alternative formulations (ferrous gluconate or ferrous fumarate) may be substituted if ferrous sulfate is not tolerated 4.

Expected Response and Monitoring

• Hemoglobin should rise by 2 g/dL after 3-4 weeks of treatment 4, 1.
• Continue oral iron for 3 months after hemoglobin normalizes to replenish iron stores 4, 1.
• Monitor hemoglobin and ferritin every 3 months for the first year, then annually 1.
• Failure to respond suggests poor compliance, continued blood loss, malabsorption, or misdiagnosis 4.

When to Consider Intravenous Iron

• Switch to intravenous iron if the patient cannot tolerate at least two different oral iron preparations, or if there is evidence of malabsorption 1, 2.
• IV iron may be needed earlier if compliance is unreliable or if rapid correction is required 1, 2.

Mandatory Investigation for Source of Blood Loss

Gastrointestinal Evaluation

• At age 72, this patient requires both upper endoscopy with small bowel biopsy AND colonoscopy (or barium enema) to identify the source of iron deficiency 4, 1.
• This is critical because 90% of patients over 45 years with unexplained iron deficiency anemia should undergo complete GI evaluation 4.
• Do not assume dietary deficiency alone in an elderly patient—occult GI malignancy or other pathology must be excluded 1.

Additional Testing

• Screen for celiac disease with antiendomysial antibodies and IgA levels 4, 1.
• Check for hematuria to exclude urinary tract sources 4.
• Faecal occult blood testing is not useful as it is insensitive and non-specific 4.

Management of Concurrent Electrolyte Abnormalities

Hyponatremia (Sodium 128)

• Assess volume status and determine if hyponatremia is hypovolemic, euvolemic, or hypervolemic.
• Review medications and discontinue offending agents if present.
• Correct slowly (no more than 8-10 mEq/L in 24 hours) to avoid osmotic demyelination syndrome.

Hyperkalemia (Potassium 5.4)

• Obtain ECG to assess for cardiac effects.
• Discontinue potassium-sparing medications and supplements.
• Consider acute treatment if ECG changes present or potassium continues to rise.
• The combination of low sodium and high potassium suggests possible adrenal insufficiency or medication effect—investigate accordingly.

Common Pitfalls to Avoid

• Do not stop iron supplementation prematurely—continue for 3 months after hemoglobin normalizes to replenish stores, as premature discontinuation leads to rapid recurrence 1.
• Do not prescribe excessive iron doses (>200 mg daily)—this increases side effects and paradoxically reduces absorption due to hepcidin elevation 1.
• Do not skip the GI investigation in elderly patients—assuming dietary insufficiency alone in a 72-year-old risks missing serious pathology like colorectal cancer 1.
• Do not give iron doses in divided amounts throughout the day—single morning doses maximize absorption 3.
• Do not ignore the electrolyte abnormalities—these require concurrent management as they pose immediate risks [@general medical knowledge].

Follow-Up Strategy

• Recheck hemoglobin, ferritin, and electrolytes in 3-4 weeks [@2@, 1].
• If hemoglobin has not risen by 2 g/dL, reassess for compliance, continued blood loss, or malabsorption [4, @2@].
• Schedule GI investigations urgently—do not delay while waiting for iron response [@2@, 1].
• Monitor hemoglobin and MCV every 3 months for one year, then annually [@4