A 53-year-old woman is being treated for tuberculosis with INH and rifampin.For the above patient with new symptoms, select the most likely acid base disorder.
**Core Concept:** Acid-base disorders are conditions in which the balance of acids and bases in the body is disrupted, leading to alterations in pH and bicarbonate levels. The most common acid-base disorders include respiratory acidosis, respiratory alkalosis, and renal acidosis/alkalosis. Tuberculosis treatment with INH (isoniazid) and rifampin can cause renal dysfunction and electrolyte imbalances.
**Why the Correct Answer is Right:** The correct answer is renal acidosis (option D) because INH and rifampin can cause renal tubular dysfunction leading to impaired renal acidification. This results in an increased base deficit and a decreased serum bicarbonate level, which is characteristic of renal acidosis.
**Why Each Wrong Option is Incorrect:**
A. Respiratory acidosis (option C) is incorrect because tuberculosis treatment does not directly affect the respiratory system.
B. Respiratory alkalosis (option B) is incorrect because the treatment does not lead to increased carbon dioxide levels or respiratory compensation.
Electrolyte imbalances, such as hypokalemia or hypomagnesemia, are not the primary concern in the context of this question. Although these electrolyte issues can contribute to acid-base imbalances, they are not the primary cause in this case.
**Clinical Pearl:** In patients receiving INH and rifampin for tuberculosis treatment, close monitoring of renal function and electrolyte levels is crucial. Early detection and management of renal dysfunction can prevent the development of more severe acid-base disturbances.
**Correct Answer: Renal Acidosis (Option D)**
The correct answer, renal acidosis, occurs due to the impaired renal tubular function induced by INH and rifampin. These drugs can cause hypomagnesemia, which can lead to renal tubular dysfunction. This results in inadequate renal acidification, causing a decrease in serum bicarbonate level and an increase in base excess, both of which are seen in renal acidosis.