Metabolic Alkalosis: What Is the Cause?

In the April issue of the American Journal of Kidney Diseases, Yi et al present an interesting teaching case of metabolic alkalosis from an unsuspected ingestion.  A pathophysiologic approach to this alkalosis includes the use of urine pH and anion gap.

There are multiple causes of metabolic alkalosis, and we have developed a set of anagrams to explore these causes. Test your knowledge!

An anagram is a type of word play, a set of jumbled letters that can be rearranged to find a hidden answer (original word/phrase). For example, “main party here (1 word)”is an anagram for “hypernatremia.” Each anagram is followed by a hint meant to intellectually direct the reader towards the correct answer. The number of words that would form the final answer is indicated in parentheses next to the anagram.

1.SIR, MY DOLL ENDED! (2 words)

An otherwise healthy 22-year-old man was found to have an elevated blood pressure of 152/90 mm Hg on a pre-employment checkup. His electrolyte panel showed a serum sodium of 144 mmol/L, potassium of 2.8 mmol/L, and serum carbon dioxide of 30 mmol/L. An arterial blood gas revealed a pH of 7.52, PCO2 of 45 mmHg, and bicarbonate of 32 mmol/L. Further workup revealed low plasma renin and aldosterone levels, normal cortisol level, low urinary aldosterone level, and normal urinary cortisol level. After an extensive battery of tests, a rare genetic disorder was diagnosed.  He was started on amiloride, a drug that is a specific inhibitor of the channel that is over expressed in this syndrome.

2. RANDOMLY SILK LIKE ‘EM (3 words)

A 68-year-old woman with past medical history of hypertension, peptic ulcer disease, and osteopenia presented to the hospital with acute onset of nausea, vomiting, constipation, and dizziness. Her medications include hydrochlorothiazide 25 mg daily, metoprolol 50 mg daily, and calcium carbonate 500 mg three times daily. A basic metabolic panel demonstrated a serum sodium of 138 mmol/L, potassium 3.2 mmol/L, chloride of 92 mmol/L, serum carbon dioxide 34 mmol/L, serum urea nitrogen 30 mg/dL, creatinine 1.8 mg/dL, eGFR 34 ml/min/1.73m2, and total serum calcium 11 mg/dL. What is the cause of the patient’s hypercalcemia and metabolic alkalosis?

3. CROATION COOK INSTALLS (2 words)

A 75-year-old man with congestive heart failure presented to his physician with worsening dyspnea on exertion, 3+ bilateral lower extremity swelling, and complaints of increased weight gain.  The physician decided to increase furosemide from 20 mg orally every 24 hours to 80 mg orally every 12 hours over the course of one week. On reevaluation, the patient had dramatically less swelling and improved exertional tolerance. Repeat blood work revealed a potassium of 3.0 mmol/L and an elevated bicarbonate of 30 mmol/L. The patient’s blood pressure was 107/80 mm Hg. What is the most likely diagnosis to explain the mechanism for the elevated bicarbonate in this patient?

4. AXE OR AN AVERSION (2 words)

 An 18-year-old woman is evaluated for metabolic alkalosis. Her urinary pH is 8 and urine anion gap is 60 mEq/L. You suspect a clandestine behavior in the individual. This disease entity is one such cause of induced behaviors.

 

Here’s to a fruitful learning experience!

Questions prepared by Mohini Alexander, MD, and Ezra Israel, MD, Nephrology Fellows, Hofstra NSLIJ School of Medicine

Edited by Kenar D. Jhaveri, MD, eAJKD Blog Editor

Answers can be found here.

To view the article abstract or full-text (subscription required), please visit AJKD.org.

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