From the Guidelines
Gitelman syndrome is characterized by distinct laboratory abnormalities, including hypokalemia, metabolic alkalosis, hypomagnesemia, hypocalciuria, and hypochloremia, with elevated plasma renin activity and aldosterone levels. These findings are a result of the impaired function of the thiazide-sensitive sodium-chloride cotransporter in the distal convoluted tubule, leading to excessive urinary losses of sodium and chloride, and subsequent compensatory mechanisms that result in potassium and hydrogen ion secretion, causing hypokalemia and metabolic alkalosis 1. Key laboratory features include:
- Hypokalemia (low potassium levels)
- Metabolic alkalosis (elevated bicarbonate levels)
- Hypomagnesemia (low magnesium levels)
- Hypocalciuria (decreased calcium excretion in urine)
- Hypochloremia (low chloride levels)
- Elevated plasma renin activity and aldosterone levels as secondary responses to the underlying defect. It's worth noting that some patients with Bartter syndrome, particularly those with BS3, may exhibit features similar to Gitelman syndrome, but the presence of hypercalciuria and nephrocalcinosis can help distinguish between the two conditions 1.
From the Research
Lab Abnormalities in Gitelman Syndrome
The lab abnormalities commonly seen in Gitelman syndrome include:
- Hypokalemic metabolic alkalosis 2, 3, 4, 5, 6
- Hypomagnesemia 2, 3, 4, 5, 6
- Hypocalciuria 2, 3, 4, 5, 6
- Increased activity of renin-angiotensin-aldosterone system 2
- Increased chloride excretion 6
- Hypophosphatemia (occasionally) 6
- Hyponatremia (rarely) 6
- Glucose intolerance/insulin resistance 6
Electrolyte Abnormalities
Electrolyte abnormalities in Gitelman syndrome are characterized by:
- Low plasma potassium concentration (<3.5 mmol/l) 4
- Low serum magnesium concentration 4, 5
- Normal or low blood pressure 2, 3
- Metabolic alkalosis 2, 3, 4, 5, 6
Urinary Abnormalities
Urinary abnormalities in Gitelman syndrome include: