Bartter syndrome is a group of similar rare conditions that affect the kidneys. It's genetic, which means it's caused by a problem with a gene.
If you have it, too much salt and calcium leave your body when you pee. It also may cause low levels of potassium and high levels of acid in the blood. If all these are out of balance, you can have many different health problems.
There are two major forms of Bartter syndrome. Antenatal Bartter syndrome starts before birth. It can be very serious, even life threatening. Babies may not grow as they should in the womb, or they may be born too early.
The other form is called classic. It usually starts in early childhood and isn't as severe as the antenatal form. But it can affect growth and cause developmental delays.
Gitelman syndrome is a subtype of Bartter syndrome. It tends to happen later -- usually from age 6 through adulthood.
Symptoms can be different for everyone, even for people with the same condition. Some common ones include:
- Frequent urination
- Generally feeling unwell
- Muscle weakness and cramping
- Salt cravings
- Severe thirst
- Slower than normal growth and development
Antenatal Bartter syndrome may be diagnosed before birth. It can be found if there are signs the baby's kidneys aren't working right or there's too much fluid in the womb.
Newborns with this form of the syndrome may pee very often and can have:
- Dangerously high fevers
- Vomiting and diarrhea
- Unusual facial features such as triangle-shaped face, large forehead, large pointed ears
- Lack of normal growth
- Deafness at birth
Genes carry instructions that help your body work right. Genetic diseases can happen when there's a change in the gene (called a mutation).
At least five genes are linked to Bartter syndrome, and they all play an important role in how your kidneys work -- especially in your ability to take in salt. Losing too much salt through pee (salt wasting) can affect how your kidneys take in other substances, including potassium and calcium.
A lack of balance in these elements can lead to serious problems:
- Too little salt can cause dehydration, constipation, and frequent peeing.
- Too little calcium can weaken bones and cause frequent kidney stones.
- Low blood levels of potassium can cause muscle weakness, cramping, and fatigue.
Diagnosis and Treatment
For children with symptoms of classic Bartter syndrome, a doctor will do a thorough exam along with blood and urine tests. The antenatal form can be diagnosed before birth by testing the amniotic fluid in the womb.
Genetic testing may also be done. Your child's doctor will take blood and possibly small samples of tissue so a specialist can look for mutations.
Once your child is diagnosed, their care may involve a team of specialists, including pediatricians, kidney experts, and social workers. To make sure they keep a healthy balance of fluids and other important things, one or several of these may be recommended:
- Indomethacin, an anti-inflammatory drug that helps their body make less urine
- Potassium-sparing diuretics, which help them keep potassium
- RAAS inhibitors, which help keep them from losing potassium
- Calcium, potassium or magnesium supplements or a combination of them
- Food high in salt, water, and potassium
- Fluids put directly into a vein (for infants with severe forms)
Because there's no cure, people who have Bartter syndrome will need to take certain medications or supplements for life.