Overview

Bartter Syndrome is a rare inherited disorder that affects the kidneys and disrupts the body's ability to reabsorb certain salts, such as sodium, potassium, chloride, and calcium. Named after the American paediatrician Frederic Bartter, who first described the condition in the 1960s, Bartter syndrome is characterised by electrolyte imbalances, resulting in various symptoms and potential complications.

The medical condition also leads to the inability of the kidney to absorb vital salts such as potassium, calcium, magnesium, sodium, and chloride. The rarity of the disease is 1 case among 1 million people, as per studies.

Causes of Bartter Syndrome

The primary cause behind Bartter syndrome is genetic mutations that affect the functioning of specific transporters and channels in the kidney tubules. These mutations interfere with the reabsorption of salts such as sodium, potassium, etc. This leads to the characteristic electrolyte imbalances seen in Bartter syndrome. Several known genes are associated with Bartter syndrome, and the specific gene involved determines the subtype and severity of the condition.

Here are subtypes of Bartter syndrome and associated genetic issues

- Bartter syndrome type 1: This subtype is caused by SLC12A1 gene mutations, which encode the protein NKCC2 (Na-K-2Cl cotransporter) responsible for salt reabsorption in the thick ascending limb of the loop of Henle.
- Bartter syndrome type 2: This subtype is caused by KCNJ1 gene mutations, which code for the ROMK (renal outer medullary potassium) channel. ROMK is involved in potassium reabsorption in the thick ascending limb of the loop of Henle.
- Bartter syndrome type 3: This subtype is caused by CLCNKB gene mutations, which encode the ClC-Kb chloride channel. The ClC-Kb channel is involved in chloride reabsorption in the thick ascending limb of the loop of Henle.
- Bartter syndrome type 4A: Mutations in the BSND gene, which encodes barttin, result in this subtype. Barttin is an essential accessory protein required for the proper function of chloride channels in the thick ascending limb of the loop of Henle.
- Bartter syndrome type 4B: This subtype is caused by mutations in the CLCNKA gene, which also encodes a chloride channel, ClC-Ka, involved in chloride reabsorption in the thick ascending limb of the loop of Henle.

Symptoms of Bartter Syndrome

- Bartter Syndrome symptoms may vary for each patient depending upon the current health update of the affected individual. However, mentioned below are some of the common symptoms that can help identify the illness in its initial stages:
- Constipation- Constipation is one of the symptoms of a rare kidney ailment. The inability of the kidneys to filter waste from the body and absorb vital nutrients leads to constipation and other medical issues. The affected patient may be unable to carry out routine functions smoothly and may stay agitated for most of the day.
- Weakness- The affected individual may feel sick and unwell to perform daily activities. It happens due to low absorption of vital salts such as potassium, calcium, sodium, and others. The patient needs help to concentrate on daily activities.
- Salt Cravings- Improper balance of vital salts and electrolytes due to the non-functioning of the kidneys may make the affected individual crave salts. The medical condition might also accompany other illnesses such as weakness, constipation, frequent urination, and other similar illnesses.
- Metabolic alkalosis- The excessive loss of chloride from the kidneys can cause a condition known as metabolic alkalosis, characterised by an imbalance in the body's acid-base levels, resulting in symptoms like nausea, vomiting, and weakness.
- Muscle Weakness- Improper kidney functioning due to different underlying kidney ailments can lead to different medical issues. The individual cannot absorb vital nutrients and salts such as potassium, calcium, sodium, and other necessary electrolytes. Low potassium levels can weaken the muscles and make it difficult for the suffering individual to carry out tedious activities or perform normal routine functions in severe stages.
- Severe Thirst- The affected individual feels thirsty even after having enough liquids. The condition happens due to the body's loss of salts and electrolytes. The affected patient might also feel sick and constipated depending upon the health update of the patient. Loss of salts might also make the individual feel the urge to urinate frequently.
- Slow Growth- Children affected by Bartter Syndrome experience slower growth than a healthy child's growth. It happens due to salt wasting and the inability of the kidney to absorb sodium, potassium, calcium, and vital electrolytes. Therefore, children suffering from kidney ailments cannot solve difficult maths equations quickly, unlike healthy kids around them. Often, such kids are also found with abnormal body growth or improper brain functioning due to a lack of important nutrients. The disorder can also be identified in unborn children if their kidneys don't function as they should.
- Excessive urination (polyuria)- Individuals with Bartter syndrome tend to produce large amounts of urine, leading to an increased frequency of urination.

Treatment Options for Bartter Syndrome

Researchers state that there is no permanent cure for this rare kidney ailment. The individual will have to consume the suggested medication for a lifetime to control the disease's symptoms and allow the affected individual to live a normal routine life. Mentioned below are some of the suggested Bartter Syndrome treatment options and medications to lower the symptoms of the disease:

- Indomethacin- The affected individual feels the urge to urinate frequently. Doctors may suggest indomethacin to lower the urge to urinate frequently and make routine functions hassle-free. The condition is usually observed in children. The medication also relieves pain in conditions such as arthritis and gout.
- Potassium Sparing Diuretics- Such diuretics help the affected individual absorb and maintain the potassium in the body. The individual does not feel weakness or frequent urge to urinate.
- Supplements- Doctors suggest including calcium, potassium, and magnesium supplements in the diet to recover the loss of vital nutrients and lower the symptoms of the kidney ailment.
- Electrolyte replacement- Individuals with Bartter syndrome may require oral supplementation of specific electrolytes, such as potassium, sodium, and chloride, to maintain appropriate levels in the body. Dosages are determined based on individual needs and regular monitoring of electrolyte levels.
- Diet- In case of kidney disease, the doctor may suggest consuming foods high in salts, water, and potassium. It is always advisable to make any changes in the diet or medication under a doctor's supervision.

When to consult a Doctor

You can also get in touch with the expert Nephrology doctors at Narayana Healthcare based in your city to get immediate attention and medical support during injuries, health disorders or any other health concern.

Conclusion

Bartter Syndrome is a compilation of different types of kidney diseases(caused by different mutations) affecting the functioning of the organ. As a result, the affected individual's kidney cannot absorb vital salts and electrolytes. Proper and timely medications help lower the disease symptoms and allow the individual to perform routine functions hassle-free.

Reference Links

- https://www.narayanahealth.org/blog/hemolytic-uremic-syndrome-causes-symptoms-and-treatment-options/
- https://rarediseases.org/rare-diseases/bartters-syndrome/
- https://www.webmd.com/children/bartter-syndrome-facts