Why Is Bartter Syndrome Called Salt Wasting Nephropathy?
This article discusses about an inherited pathological condition of the kidneys called Bartter Syndrome. In this syndrome, there is progressive loss of potassium from the body through urine resulting in several complications. In this article, we will discuss about the causes, symptoms, and various treatments rendered for Bartter Syndrome and also get to know why is Bartter Syndrome also known as Salt Wasting Nephropathy or Potassium Wasting.
How Is Bartter Syndrome Defined?
- Congenital Disease- Bartter's Syndrome is an inherited medical condition. Kidney consists of defective renal tubules.1
- Abnormal Renal Tubule- Renal tubule excretes excessive potassium and chloride, which results in reduced potassium and chloride levels.
- Hypokalemia- Low potassium and chloride level causes metabolic alkalosis.2
- Types of Bartter Syndrome- Bartter Syndrome are expressed as Classic and Neonatal Bartter Syndrome.
- Neonatal Bartter Syndrome- Needs prompt and appropriate treatment. The condition is an emergency.
- Classic Bartter Syndrome-
- Symptoms become significant during school age.
- Symptoms consist of polyuria, polydipsia, and dehydration.
- History of Kidney Stone- Caused by increased urinary calcium resulting in formation of kidney stones.
- Phenotype- There are at least three phenotypes that have been identified. They are as follows:
- Classic Bartter Syndrome
- The Gitelman Variant
- The Antenatal Variant
Causes of Bartter Syndrome
As stated, Bartter Syndrome or Salt Wasting Nephropathy is a group of closely knitted disorders, which affect the kidneys.
- There are five gene defects, which have been proven to be associated with Bartter syndrome.1
- This condition is congenital and is present before birth.
Why Is Bartter Syndrome Known As Salt Wasting Nephropathy or Potassium Wasting?
- Hypokalemia- Bartter Syndrome is caused by a pathological condition of the kidneys where the kidneys are unable to absorb sodium.
- Hyper Aldosterone level- Individuals with Bartter syndrome start to lose excessive sodium via urine resulting in elevation of aldosterone levels, which makes the kidney discard excessive potassium from the body.
- Potassium Wasting- Barter Syndrome is known as potassium wasting because potassium is discarded in urine resulting in hypokalemia.This phenomenon is called potassium wasting or salt wasting nephropathy.
- Alkalosis- This condition also affects the acid balance in blood resulting in a condition called Hypokalemic Alkalosis, which is responsible for causing excessive calcium in the urine.2
What Is Neonatal Bartter Syndrome?
- Mother of carrying fetus with Neonatal Bartter Syndrome secretes excessive amount of amniotic fluid (polyhydramnios).
- Diagnosis is confirmed after birth following blood and urine examination.
- Infant suffering with Neonatal Bartter Syndrome urinate (polyuria) and drink (polydipsia) excessive fluid.
- Large amount of calcium (hypercalciuria) is excreted in urine, which result in formation of kidney stone.
Symptoms of Bartter Syndrome
Bartter Syndrome commonly occurs in childhood years. Some of the symptoms of Bartter Syndrome are as follows-
- Growth retardation or failure to thrive,3
- Increased urinary frequency
- Kidney stone
- Muscle cramping
Diagnosis of Bartter Syndrome
Blood Examination for Bartter Syndrome
- Hypokalemia- Low serum or blood potassium level
- Hypocalcemia- Low serum calcium level
- Low serum chloride level
- Elevated aldosterone level
- Metabolic alkalosis
- Increased plasma renin
Urine Examination for Bartter Syndrome
- Elevated potassium, calcium, and chloride levels in urine
Renal Biopsy for Bartter Syndrome
- Hyperplasia of juxtra-glomerular apparatus.
Diagnostic Criteria for Bartter Syndrome
- Low serum potassium and high urine potassium level
- Low serum chloride and urine chloride level
- Low serum calcium and high urine calcium level.
- Increased plasma renin
- Renal biopsy
Treatment for Bartter Syndrome
Maintain Potassium Level-
- To treat Bartter Syndrome, it is imperative to maintain adequate potassium levels in the body.
- This can be done by following a potassium rich diet or taking potassium supplements.
- Apart from potassium supplements, people also may need magnesium supplements and medications, which prohibit excretion of potassium from the kidney.
- Sodium intake should be closely monitored.
Diuretics For Bartter Syndrome-
- Spironolactone- Spironolactone diuretic spares potassium loss. If treated with spironolactone then child should be given adequate fluid to prevent dehydration.
Anti-inflammatory Medications For Bartter Syndrome-
- High doses of NSAIDs are also used to treat Bartter Syndrome.
Anti-Hypertensive Medications For Bartter Syndrome-
- Ace Inhibitors- Angiotensin converting enzyme inhibitors are used to treat hypertension and hyperkalemia.
Prognosis of Bartter Syndrome
- Early diagnosis and treatment of Bartter Syndrome may prevent long term complications like neurointellectual function.
- Children with early growth retardation may improve and start growing normally with proper treatment.4
- Most of the people with Bartter Syndrome get better with treatment and few may end up with end stage renal disease.
1. Autosomal dominant hypocalcemia with mild type 5 Bartter syndrome.
Vezzoli G1, Arcidiacono T, Paloschi V, Terranegra A, Biasion R, Weber G, Mora S, Syren ML, Coviello D, Cusi D, Bianchi G, Soldati L.
J Nephrol. 2006 Jul-Aug;19(4):525-8.
2. Use of calcium excretion values to distinguish two forms of primary renal tubular hypokalemic alkalosis: Bartter and Gitelman syndromes.
Bettinelli A1, Bianchetti MG, Girardin E, Caringella A, Cecconi M, Appiani AC, Pavanello L, Gastaldi R, Isimbaldi C, Lama G, et al.
J Pediatr. 1992 Jan;120(1):38-43.
3. Classic Bartter syndrome: a rare cause of failure to thrive in a child.
Vieira H1, Mendes L, Mendes P, da Silva JE.
BMJ Case Rep. 2012 Jun 28;2012. pii: bcr0220125888.
4. Long-term follow-up of patients with Bartter syndrome type I and II.
Puricelli E1, Bettinelli A, Borsa N, Sironi F, Mattiello C, Tammaro F, Tedeschi S, Bianchetti MG; Italian Collaborative Group for Bartter Syndrome.
Nephrol Dial Transplant. 2010 Sep;25(9):2976-81.