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Bartter syndrome
Classification and external resources

Scheme of renal tubule and its vascular supply.
ICD-10 E26.8
ICD-9 255.13
OMIM 601678 241200 607364 602522
DiseasesDB 1254
eMedicine med/213 ped/210
MeSH D001477

Bartter syndrome is a rare inherited defect in the thick ascending limb of the loop of Henle. It is characterized by low potassium levels (hypokalemia), decreased acidity of blood (alkalosis), and normal to low blood pressure. There are two types of Bartter syndrome: neonatal and classic. A closely associated disorder, Gitelman syndrome, is milder than both subtypes of Bartter syndrome.

Contents

Features

In 90% of cases, neonatal Bartter syndrome is seen between 24 and 30 weeks of gestation with excess amniotic fluid (polyhydramnios). After birth, the infant is seen to urinate and drink excessively (polyuria, and polydipsia, respectively). Life-threatening dehydration may result if the infant does not receive adequate fluids. About 85% of infants dispose of excess amounts of calcium in the urine (hypercalciuria) and kidneys (nephrocalcinosis), which may lead to kidney stones. In rare occasions, the infant may progress to renal failure.

Patients with classic Bartter syndrome may have symptoms in the first two years of life, but they are usually diagnosed at school age or later. Like infants with the neonatal subtype, patients with classic Bartter syndrome also have polyuria, polydipsia, and a tendency to dehydration, but normal or just slightly increased urinary calcium excretion without the tendency to develop kidney stones. These patients also have vomiting and growth retardation. Kidney function is also normal if the disease is treated,[1] but occasionally patients proceed to end-stage renal failure. Bartter's syndrome consists of hypokalaemia, alkalosis, normal blood pressures, and elevated plasma renin and aldosterone. Numerous causes of this syndrome probably exist. Diagnostic pointers include high urinary potassium and chloride despite low serum values, increased plasma renin, hyperplasia of the juxtaglomerular apparatus on renal biopsy, and careful exclusion of diuretic abuse. Excess production of renal prostaglandins is often found. Magnesium wasting may also occur.

Diagnosis

People suffering from Bartter syndrome present symptoms which are identical to those of patients who are on loop diuretics like furosemide.

The clinical findings characteristic of Bartter syndrome are hypokalemia, metabolic alkalosis, and normal to low blood pressure. These findings may also be caused by:

  • Chronic vomiting: These patients will also have low urine chloride levels
  • Abuse of diuretic medications (water pills): The physician must screen urine for multiple diuretics before diagnosis is made.
  • Magnesium deficiency: These patients will also have low serum and urine magnesium

Patients with Bartter syndrome may also have elevated renin and aldosterone levels.[2]

Prenatal Bartter syndrome can be associated with polyhydramnios.[3]

Pathophysiology

Bartter syndrome is caused by mutations of genes encoding proteins that transport ions across renal cells in the thick ascending limb of the nephron.[1]

Bartter and Gitelman syndromes can be divided into different subtypes based on the genes involved:[4]

Name Bartter type Associated gene mutations Defect
neonatal Bartter's syndrome type 1 NKCC2 Na-K-2Cl symporter
neonatal Bartter's syndrome type 2 ROMK thick ascending limb K+ channel
classic Bartter's syndrome type 3 CLCNKB Cl- channel
Bartter's syndrome with sensorineural deafness type 4 BSND[5] Cl- channel
Bartter's syndrome associated with autosomal dominant hypocalcemia type 5 CASR[6] calcium-sensing receptor
Gitelman's syndrome - SLC12A3 (NCCT) Sodium-chloride symporter

Treatment

While patients should be encouraged to include liberal amounts of sodium and potassium in their diet, potassium supplements are usually required, and spironolactone is also used to reduce potassium loss. [7]

Nonsteroidal antiinflammatory drugs (NSAIDs) can be used as well, and are particularly helpful in patients with neonatal Bartter's syndrome.

Angiotensin-converting enzyme (ACE) inhibitors can also be used.

Prognosis

The limited prognostic information available suggests that early diagnosis and appropriate treatment of infants and young children with Classic Bartter Syndrome may improve growth and perhaps neurointellectual development. On the other hand, sustained hypokalemia and hyperreninemia can cause progressive tubulointerstitial nephritis, resulting in end-stage-renal disease (Kidney failure). With early treatment of the electrolyte imbalances the prognosis for patients with Classic Bartter Syndrome is good.

History

The condition is named after Dr. Frederic Bartter, who, along with Dr. Pacita Pronove, first described it in 1960 and in more patients in 1962.[2][8][9][10]

Related conditions

  • Bartter and Gitelman syndromes are both characterized by hypokalemia, normal to low blood pressure, and hypochloremic metabolic alkalosis.[11]

References

  1. ^ a b Rodriguez-Soriano J (1998). "Bartter and related syndromes: the puzzle is almost solved". Pediatr Nephrol 12 (4): 315–27. doi:10.1007/s004670050461. PMID 9655365.  
  2. ^ a b Bartter FC, Pronove P, Gill JR Jr, MacCardle RC (1962). "Hyperplasia of the juxtaglomerular complex with hyperaldosteronism and hypokalemic alkalosis. A new syndrome". Am J Med 33: 811–28. doi:10.1016/0002-9343(62)90214-0. PMID 13969763.   Reproduced in Bartter FC, Pronove P, Gill JR, MacCardle RC (1998). "Hyperplasia of the juxtaglomerular complex with hyperaldosteronism and hypokalemic alkalosis. A new syndrome. 1962". J. Am. Soc. Nephrol. 9 (3): 516–28. PMID 9513916.  
  3. ^ Dane B, Yayla M, Dane C, Cetin A (2007). "Prenatal diagnosis of Bartter syndrome with biochemical examination of amniotic fluid: case report". Fetal. Diagn. Ther. 22 (3): 206–8. doi:10.1159/000098719. PMID 17228161. http://content.karger.com/produktedb/produkte.asp?typ=fulltext&file=000098719.  
  4. ^ Naesens M, Steels P, Verberckmoes R, Vanrenterghem Y, Kuypers D (2004). "Bartter's and Gitelman's syndromes: from gene to clinic". Nephron Physiol 96 (3): p65–78. doi:10.1159/000076752. PMID 15056980.  
  5. ^ Zaffanello M, Taranta A, Palma A, Bettinelli A, Marseglia GL, Emma F (2006). "Type IV Bartter syndrome: report of two new cases". Pediatr. Nephrol. 21 (6): 766–70. doi:10.1007/s00467-006-0090-x. PMID 16583241.  
  6. ^ Vezzoli G, Arcidiacono T, Paloschi V, et al. (2006). "Autosomal dominant hypocalcemia with mild type 5 Bartter syndrome" (). J. Nephrol. 19 (4): 525–8. PMID 17048213. http://www.sin-italy.org/jnonline/Vol19n4/525.html.  
  7. ^ "Bartter Syndrome: Tubular and Cystic Kidney Disorders: Merck Manual Home Edition". http://www.merck.com/mmhe/sec11/ch146/ch146i.html. Retrieved 2007-12-31.  
  8. ^ Proesmans W (2006). "Threading through the mizmaze of Bartter syndrome". Pediatr. Nephrol. 21 (7): 896–902. doi:10.1007/s00467-006-0113-7. PMID 16773399.  
  9. ^ synd/2328 at Who Named It?
  10. ^ http://www.whonamedit.com/synd.cfm/2328.html
  11. ^ Gitelman HJ, Graham JB, Welt LG (1966). "A new familial disorder characterized by hypokalemia and hypomagnesemia". Trans Assoc Am Physicians 79: 221–35. PMID 5929460.  

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