Understanding Bartter Syndrome

There are several conditions that require patients to monitor their salt and sodium levels, and many of them remain relatively unknown among the general population. One set of relatively rare conditions that require an increase in dietary sodium is Bartter Syndrome. 

What is Bartter Syndrome?

Despite the name, Bartter Syndrome is not a single syndrome – rather, it is a group of syndromes, all of which affect the kidneys and are genetic. 

There are two major types of Bartter Syndrome^[1]:

• Antenatal Bartter Syndrome: This is a version of the syndrome where the effects appear before a child’s birth, during pregnancy. This version of Bartter Syndrome is extremely serious and can be life-threatening, as it prevents the normal development of the child in the womb.

• Classic Bartter Syndrome: This form of the syndrome occurs after birth. It isn’t as severe as Antenatal Bartter Syndrome but can cause severe issues, including growth and developmental delays. 

Bartter Syndrome essentially prevents your body from holding on to salt and calcium. People with this syndrome experience the loss of extremely high levels of these minerals in their urine, which can lead to a host of dangerous and potentially debilitating symptoms. 

Symptoms of excessive salt loss include: 

• Polyuria: Resulting in increased urination, causing a vicious cycle of losing even more salt and calcium^[2]
• Dehydration: The human body needs a balanced intake of salts and water to stay hydrated. Excessive loss of either causes dehydration.
• Constipation
• Hypercalciuria: In which some of the calcium excreted by the body is deposited in the kidneys instead of leaving the body through the urine. This leads to a hardening of the kidney tissue.
• Muscle weakness and cramping
• Low levels of blood potassium
• Inner ear abnormalities

Bartter Syndrome is either diagnosed before birth (antenatal) or after birth (classic). It shows up in the child from infancy and can lead to dangerous levels of urination for infants. Other symptoms that affect infants and can be used as a way to diagnose Bartter Syndrome include:

• Vomiting and diarrhea
• Unusual facial features
• Dehydration and dangerously high fevers
• In rare cases, deafness at birth that is caused by inner ear abnormalities

What Causes Bartter Syndrome? 

As mentioned above, Bartter Syndrome is a genetic disorder. It is an autosomal recessive disorder^[3], meaning that both parents must be carriers of the disorder, though they may not have the disorder themselves. 

In rare cases, it may be an X-linked recessive disorder, which means the illness is passed down from a carrier mother to the child. In such cases, only a boy child would show symptoms of the disorder – girl children would be carriers instead. This is because, in males (XY), there is only one X gene, and any illnesses carried on that gene affect the person. In a female (XX), there are two X genes, and if the illness is recessive (as Bartter Syndrome is), the other, unaffected X gene essential prevents the illness from “activating,” ensuring the child is unaffected themselves – but a carrier for the illness^[4].

In most cases of Bartter Syndrome, a mutation in any one of at least five genes is linked to the illness, depending on the type of Bartter Syndrome a child has. All these genes play an important role in ensuring normal kidney function in healthy individuals, especially in regulating the kidneys’ role in the reabsorption of salt. Mutations in any one (or all) of these genes affect the ability of the kidneys to reabsorb salt, leading to excess salt being excreted in the urine. 

This also impacts the absorption of a range of other minerals, especially potassium and calcium, resulting in the major symptoms of Bartter Syndrome. 

• Lack of salt in the body causes dehydration, excess urination, and constipation
• Lack of calcium results in weaker bones and kidney stones
• Lack of potassium in the blood results in weakness in the muscles, cramps, and excess fatigue and tiredness

It should be noted that these gene abnormalities are the only ones that are known to scientists so far. There are some individuals who do not have these abnormalities but still have Bartter Syndrome. The cause of the disorder in these individuals is unknown and is still being researched. 

Treating Bartter Syndrome

As a chronic disease, there is currently no cure for Bartter Syndrome. However, there are ways to mitigate and manage the symptoms so that people with this disorder can lead a relatively normal life. With proper management, the long-term prognosis for people with Classic Bartter Syndrome, in particular, is good[5].

The first step in treatment is getting a positive diagnosis. Diagnosis may involve genetic tests, as well as blood and urine tests. For children with suspect Antenatal Bartter Syndrome, it may also involve tests of the amniotic fluid of the womb. 

It should be noted that there are a host of other conditions that seem to have the symptoms of Classic Bartter Syndrome but are not the same, including:

• Gitelman Syndrome
• EAST Syndrome
• Pseudo-Bartter Syndrome
• Autosomal Dominant Hypocalcemia Type 1

For this reason, a positive diagnosis is essential before treatment.

Following a positive diagnosis, your child’s doctors will work to address the specific symptoms that are present in your child. Not all affected individuals show all symptoms, so treatment is highly personalized. 

Some treatment options include medication that can help your body retain potassium and reduce urine production. For infants, treatment may involve direct injections of fluids in the body, especially if they have a severe case of Bartter Syndrome. As infants cannot increase fluid and salt intake, fluids injected into the veins are the only option. 

Additionally, treatment can also involve supplementation of the minerals lost by the body in excessive amounts – that is, calcium, magnesium, salt, and potassium. Especially for salt and potassium (and water), management often involves dietary changes to increase dietary salt and potassium intake. 

However, increasing dietary salt and potassium intake through food is not always possible, especially with young children who are often picky about their meals. One option is to supplement dietary intake with salt and potassium capsules, such as Klaralyte tablets. Each tablet contains 250 mg of salt and 50mg of potassium and can be had with water. 

Your doctor will advise how much to increase your consumption of these minerals. Additionally, since water is lost through urination, management of Bartter Syndrome will also generally involve an increase in water consumption. Again, your medical team will be able to advise how much water to drink daily.

Conclusion

Treatment and management of Bartter Syndrome should always be done under medical supervision. Your doctor will be able to advise which, if any, of these strategies are a fit for your child’s symptoms. Alternatively, they may put you on another treatment plan, dependent on symptoms.

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