Bartter Syndrome
An inherited kidney disorder that causes excessive salt loss
Quick Facts
- Type: Inherited kidney disorder
- Core problem: Kidneys lose too much salt and potassium
- Onset: Often in infancy or early childhood
- Blood pressure: Usually normal or low, not high
Overview
Bartter syndrome is a rare inherited disorder of the kidneys. It is caused by faults in the tiny channels and transporters that the kidneys use to reabsorb salt. As a result, the kidneys lose too much sodium, potassium, and chloride into the urine. This salt wasting leads to a characteristic pattern of low blood potassium, a chemical imbalance called metabolic alkalosis, and a tendency to dehydration.
Unlike many causes of these imbalances, blood pressure in Bartter syndrome is usually normal or low rather than high. The condition is present from birth and often appears in infancy or early childhood, though milder forms can be recognized later. There is no cure, but careful, lifelong management of fluids and minerals allows many people to do well.
Symptoms
Symptoms depend on the type and severity and often begin early in life.
- Excessive urination and strong thirst
- Dehydration and salt craving
- Muscle weakness, cramps, and fatigue from low potassium
- Poor growth and feeding difficulties in infants and children
- Constipation
- In some severe early forms, problems beginning before birth with excess fluid around the baby
Because young children may not be able to describe their symptoms, signs such as poor weight gain, frequent wet diapers, and dehydration are important clues.
Causes
Bartter syndrome is caused by inherited changes in genes that control salt handling in a specific part of the kidney's filtering units.
- Genetic basis: Faults in one of several genes affect the transporters and channels that reabsorb salt. Different genes cause different types of the syndrome.
- Inheritance: Most forms are inherited in a recessive pattern, meaning a child receives a faulty gene from each parent.
- Salt wasting: The underlying defect prevents the kidney from reclaiming salt properly, setting off the chain of mineral and fluid imbalances.
The condition is divided into types, with the early-onset (antenatal) forms generally more severe than those that appear later (classic Bartter syndrome).
Risk Factors
- A family history of Bartter syndrome
- Parents who are both carriers of the gene change
- Parents who are blood relatives, which increases the chance of recessive conditions
Diagnosis
Diagnosis is based on the pattern of blood and urine results, supported by genetic testing.
- Blood tests: Showing low potassium, the alkalosis pattern, and usually normal or low blood pressure.
- Urine tests: Demonstrating high levels of salt and other minerals being lost in the urine.
- Hormone tests: Renin and aldosterone are often raised as the body tries to hold on to salt.
- Genetic testing: Can confirm the diagnosis and identify the specific type.
Doctors also distinguish Bartter syndrome from similar disorders and from secret use of diuretics or vomiting, which can mimic it.
Treatment
There is no cure, so treatment focuses on replacing lost minerals and reducing salt loss to control symptoms and support growth.
- Potassium replacement: Oral potassium supplements to correct and maintain potassium levels.
- Salt and fluid: Generous sodium and fluid intake to keep up with losses and prevent dehydration.
- Medicines to reduce salt wasting: Certain anti-inflammatory medicines and potassium-sparing agents can lower the kidney's salt loss in some types.
- Magnesium replacement: When magnesium is also low.
- Specialist follow-up: Regular kidney specialist care, with attention to growth in children and ongoing monitoring of blood chemistry.
Prevention and Self-Care
- Bartter syndrome is inherited and cannot be prevented, but its complications can be reduced with consistent treatment
- Taking potassium and other supplements exactly as prescribed
- Maintaining good fluid and salt intake, especially during hot weather or illness
- Seeking prompt care during vomiting, diarrhea, or fever, when imbalances can worsen quickly
- Genetic counseling for families to understand inheritance and recurrence risk
When to See a Doctor
People with Bartter syndrome need regular specialist follow-up. Seek urgent care if you or your child develop:
- Signs of significant dehydration, such as very little urine, sunken eyes, or extreme thirst
- Severe muscle weakness or an irregular heartbeat from very low potassium
- Persistent vomiting or diarrhea that prevents keeping down fluids and supplements
In infants, poor feeding, lethargy, and few wet diapers are important warning signs that need prompt evaluation.
Frequently Asked Questions
What is Bartter syndrome?
Bartter syndrome is a rare inherited kidney disorder in which the kidneys lose too much salt into the urine. This causes low potassium, a chemical imbalance called metabolic alkalosis, and a tendency to dehydration, usually with normal or low blood pressure.
How is Bartter syndrome different from high blood pressure conditions?
Many conditions that cause low potassium also raise blood pressure, but in Bartter syndrome blood pressure is usually normal or low. This is because the basic problem is salt loss rather than salt retention, which helps distinguish it from disorders like hyperaldosteronism.
When does Bartter syndrome appear?
It is present from birth and often shows up in infancy or early childhood with excessive urination, dehydration, salt craving, and poor growth. Some severe forms cause problems before birth, while milder forms may be recognized later in life.
Can Bartter syndrome be cured?
There is no cure, but the condition can be managed for life by replacing lost potassium and other minerals, maintaining generous salt and fluid intake, and using medicines that reduce the kidney's salt loss. Regular specialist follow-up is important.
Is Bartter syndrome inherited?
Yes. It is caused by changes in genes that control salt handling in the kidney and is usually passed on in a recessive pattern, meaning a child inherits a faulty gene from each parent. Genetic counseling can help families understand the risk.
References
- MedlinePlus, U.S. National Library of Medicine. Bartter syndrome.
- National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK). Kidney disease.
- Genetic and Rare Diseases Information Center (GARD). Bartter syndrome.