A 32-year-old man comes to the clinic due to 5 days of severe, watery diarrhea. He recently returned from a trip to Southeast Asia. The patient reports having 8 to 10 loose bowel movements daily. He has been drinking plain water but has not consumed any food or electrolyte solutions. His temperature is 37.1°C (98.8°F), blood pressure is 108/64 mm Hg, and pulse is 104/min. Physical examination shows dry mucous membranes and decreased skin turgor. Laboratory studies show the following:
| Laboratory Test | Result |
|---|---|
| Sodium | 138 mEq/L |
| Potassium | 3.2 mEq/L |
| Chloride | 115 mEq/L |
| Bicarbonate | 15 mEq/L |
| Blood urea nitrogen | 28 mg/dL |
| Creatinine | 1.2 mg/dL |
Based on these findings, which of the following acid-base disturbances is most likely present in this patient?
- Normal anion gap metabolic acidosisCevap
- BHigh anion gap metabolic acidosis
- CMetabolic alkalosis
- DPrimary respiratory acidosis
- EPrimary respiratory alkalosis
Cevap
Normal anion gap metabolic acidosis
This patient's clinical presentation of severe diarrhea has led to significant fluid and electrolyte loss. The serum chemistry shows a low bicarbonate level (), which defines a metabolic acidosis. The next essential step in evaluating any metabolic acidosis is to calculate the serum anion gap using the formula: . For this patient, the calculation is . A normal anion gap is generally between 8 and 12 mEq/L. Therefore, this patient has a normal anion gap metabolic acidosis (NAGMA). This is physiologically consistent with his history of profuse diarrhea, which causes direct gastrointestinal loss of bicarbonate. To maintain electroneutrality, the kidneys retain chloride, resulting in the observed hyperchloremia ().
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Anahtar Kavram
Severe diarrhea causes direct gastrointestinal loss of bicarbonate, resulting in a hyperchloremic, normal anion gap metabolic acidosis.
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