Symptom Finder - Alkalosis
ALKALOSIS (INCREASED pH)
The differential diagnosis of alkalosis, like acidosis, begins with using the
physiologic model of production, excretion, or degradation.
Production: Bicarbonate is produced in the kidneys. Excessive production of bicarbonate occurs in primary or secondary aldosteronism where the hormone aldosterone induces increased bicarbonate production and excessive excretion of the hydrogen (H+) ion in exchange for sodium (Na+) reabsorption. The same mechanism occurs in exogenous steroid administration and Bartter syndrome.
Excretion: This mechanism should help recall salicylate toxicity and hyperventilation as causes of alkalosis. In these conditions, the pH is raised because of excessive excretion of CO2 through the lungs. Excessive excretion of acid also occurs in pyloric stenosis, intestinal obstruction, and other causes of excessive vomiting leading to alkalosis.
Prolonged nasogastric suctioning may lead to alkalosis by the same mechanism. Chronic antacid use, various diuretics, and Cushing disease may also induce alkalosis.
Approach to the Diagnosis
Taking a drug history and noting hyperventilation or vomiting during the clinical evaluation will assist in the diagnosis. Serial electrolytes, arterial blood gases, and drug screen are first-line laboratory tests to assist in the diagnosis.
Other Useful Tests
1. CBC (intestinal obstruction)
2. Urinalysis (renal calculi, salicylates)
3. Chemistry profile (aldosteronism, diuretic use)
4. Serum amylase and lipase levels (acute pancreatitis with vomiting)
5. Flat plate of the abdomen (intestinal obstruction)
6. Chest x-ray (pneumonia, pulmonary infarction)
7. Gastroscopy (pyloric stenosis)
8. Plasma renin and aldosterone levels (aldosteronism)
9. Urine aldosterone (primary aldosteronism)
10. Endocrinology consult
11. CT scan of the abdomen (adrenal hyperplasia or adenoma)
12. Surgery consult
The differential diagnosis of alkalosis, like acidosis, begins with using the
physiologic model of production, excretion, or degradation.
Production: Bicarbonate is produced in the kidneys. Excessive production of bicarbonate occurs in primary or secondary aldosteronism where the hormone aldosterone induces increased bicarbonate production and excessive excretion of the hydrogen (H+) ion in exchange for sodium (Na+) reabsorption. The same mechanism occurs in exogenous steroid administration and Bartter syndrome.
Excretion: This mechanism should help recall salicylate toxicity and hyperventilation as causes of alkalosis. In these conditions, the pH is raised because of excessive excretion of CO2 through the lungs. Excessive excretion of acid also occurs in pyloric stenosis, intestinal obstruction, and other causes of excessive vomiting leading to alkalosis.
Prolonged nasogastric suctioning may lead to alkalosis by the same mechanism. Chronic antacid use, various diuretics, and Cushing disease may also induce alkalosis.
Approach to the Diagnosis
Taking a drug history and noting hyperventilation or vomiting during the clinical evaluation will assist in the diagnosis. Serial electrolytes, arterial blood gases, and drug screen are first-line laboratory tests to assist in the diagnosis.
Other Useful Tests
1. CBC (intestinal obstruction)
2. Urinalysis (renal calculi, salicylates)
3. Chemistry profile (aldosteronism, diuretic use)
4. Serum amylase and lipase levels (acute pancreatitis with vomiting)
5. Flat plate of the abdomen (intestinal obstruction)
6. Chest x-ray (pneumonia, pulmonary infarction)
7. Gastroscopy (pyloric stenosis)
8. Plasma renin and aldosterone levels (aldosteronism)
9. Urine aldosterone (primary aldosteronism)
10. Endocrinology consult
11. CT scan of the abdomen (adrenal hyperplasia or adenoma)
12. Surgery consult