Bartter syndrome and the more common Gitelman syndrome result from deranged sodium chloride reabsorption. In Bartter syndrome, the defect is in the ascending thick limb of the loop of Henle. In Gitelman syndrome, the defect is in the distal tubule. In both syndromes, the impairment of sodium chloride reabsorption causes mild volume depletion, which leads to increases in renin and aldosterone release, resulting in potassium and hydrogen losses. In Bartter syndrome, there is increased prostaglandin secretion as well as a urinary concentrating defect due to impaired generation of the medullary concentration gradient. In Gitelman syndrome, hypomagnesemia and a low urinary calcium excretion are common. In both disorders, sodium wasting contributes to a chronic mild plasma volume contraction reflected by a normal to low BP despite high renin and angiotensin levels.

The features at clinical presentation vary (see Table: Some Differences Between Bartter Syndrome and Gitelman Syndrome).

Both syndromes are usually autosomal recessive, although sporadic cases and other types of familial patterns can occur. There are several genotypes of both syndromes; different genotypes can have different manifestations.

Bartter syndrome tends to manifest prenatally or during infancy or early childhood. Gitelman syndrome tends to manifest during late childhood to adulthood. Bartter syndrome can manifest prenatally with intrauterine growth restriction and polyhydramnios. Different forms of Bartter syndrome can have specific manifestations, including hearing loss, hypocalcemia, and nephrocalcinosis, depending on the underlying genetic defect. Children with Bartter syndrome, more so than those with Gitelman syndrome, may be born prematurely and may have poor growth and development postnatally, and some children have intellectual disability.

Most patients have low or low-normal BP and may have signs of volume depletion. Inability to retain potassium, calcium, or magnesium can lead to muscle weakness, cramping, spasms, tetany, or fatigue, particularly in Gitelman syndrome. Polydipsia, polyuria, and vomiting may be present.

In general, neither Bartter syndrome nor Gitelman syndrome typically leads to chronic renal insufficiency.

Bartter syndrome and Gitelman syndrome should be suspected in children with characteristic symptoms or incidentally noted laboratory abnormalities, such as metabolic alkalosis and hypokalemia. Measurement of urine electrolytes shows high levels of sodium, potassium, and chloride that are inappropriate for the euvolemic or hypovolemic state of the patient. Diagnosis is by exclusion of other disorders:

Definitive diagnosis is through genetic testing, which is rarely done because of factors such as the large number of known mutations, large gene size, and prohibitive cost.

A 24-h measurement of urinary calcium or the urine calcium/creatinine ratio may help distinguish the two syndromes; the levels are typically normal to increased in Bartter syndrome and low in Gitelman syndrome.

Because renal prostaglandin E2 secretion contributes to the pathogenesis in Bartter syndrome, NSAIDs (eg, indomethacin 1 to 2 mg/kg po once/day) are helpful; patients are also given potassium-sparing diuretics (eg, spironolactone 150 mg po bid or amiloride 10 to 20 mg po bid). Potassium-sparing diuretics alone are used in Gitelman syndrome. Low-dose ACE inhibitors can help limit the aldosterone-mediated electrolyte derangements. However, no therapy can completely eliminate potassium wasting, and potassium supplementation (KCl 20 to 40 mEq po once/day or bid) is often necessary. Magnesium supplements may also be needed.

Exogenous growth hormone can be considered to treat short stature.