What is the cause of a syncopal episode in a patient with anemia (indicated by low Red Blood Cell (RBC) count and hematocrit), hyponatremia (low sodium), and impaired renal function (elevated Blood Urea Nitrogen (BUN))?

From the Guidelines

The patient's syncopal episode should be immediately managed with intravenous fluid resuscitation and further investigation into the underlying cause of anemia, as the recent 2021 guidelines from the British Society of Gastroenterology 1 emphasize the importance of addressing iron deficiency and anemia in patients with chronic kidney disease. The patient's laboratory findings show mild anemia (low RBC count of 3.45 and hematocrit of 32.9%), mild hyponatremia (sodium 131 mEq/L), and elevated BUN (23 mg/dL) suggesting possible dehydration. Some key points to consider in the management of this patient include:

• Immediate management should include placing the patient in a supine position with legs elevated, ensuring airway patency, and monitoring vital signs.
• Intravenous fluid resuscitation with normal saline should be initiated to address potential dehydration and improve blood pressure, as recommended by the 2017 ACC/AHA/HRS guideline for the evaluation and management of patients with syncope 1.
• The anemia should be further investigated with additional tests including iron studies, vitamin B12, and folate levels.
• A thorough history and physical examination are essential to determine the cause of syncope, which could be related to the anemia, dehydration, cardiac arrhythmias, or vasovagal response.
• An ECG should be performed to rule out cardiac causes, as suggested by the 2017 ACC/AHA/HRS guideline 1.
• The patient should be advised to rise slowly from sitting or lying positions to prevent orthostatic hypotension.
• The mild hyponatremia may improve with fluid resuscitation, but sodium levels should be monitored. The European consensus on the diagnosis and management of iron deficiency and anaemia in inflammatory bowel diseases 1 provides a framework for understanding the potential causes of anemia in this patient, including iron deficiency, anemia of chronic disease, and other mechanisms. However, the most recent and highest quality study, the 2021 British Society of Gastroenterology guidelines 1, should be prioritized in guiding the management of this patient's anemia and syncopal episode.

From the Research

Syncopal Episode and Laboratory Results

The patient presented with a syncopal episode and laboratory results showing:

• RBC: 3.45
• Hematocrit: 32.9
• Sodium: 131
• Chloride: 95
• BUN: 23
• Bilirubin total: 0.2

Anemia Evaluation

According to 2, anemia is a common condition that can be detected through laboratory evaluation, including a complete blood cell count (CBC). The patient's low RBC and hematocrit levels suggest anemia. Further evaluation, such as a peripheral blood smear, reticulocyte count, and iron panel, may be necessary to determine the cause of anemia.

Causes of Anemia

3 states that anemia can be caused by decreased production of hemoglobin or red blood cells, or by increased consumption and blood loss. The patient's laboratory results do not provide a clear indication of the cause of anemia. However, the low sodium level (131) may suggest dehydration, which can contribute to anemia.

Dehydration and Anemia

4 discusses the clinical definition of dehydration and its treatment. Dehydration can lead to anemia, and the patient's low sodium level may indicate dehydration. However, further evaluation is necessary to determine the severity of dehydration and its contribution to anemia.

Differential Diagnosis

5 emphasizes the importance of differential diagnosis in guiding the diagnostic process. In this case, the patient's syncopal episode and laboratory results suggest anemia, dehydration, and possibly other underlying conditions. A comprehensive differential diagnosis should include uncommon as well as common diseases to ensure accurate diagnosis and treatment.

Potential Next Steps

Based on the patient's laboratory results and clinical presentation, potential next steps may include:

• Further evaluation of anemia, including a reticulocyte count and iron panel
• Assessment of dehydration and its contribution to anemia
• Differential diagnosis to rule out other underlying conditions
• Consideration of treatment options, such as iron supplementation or lactoferrin, as discussed in 6