It is a rare genetic disorder that causes the kidney to excrete magnesium, sodium, potassium and chloride into the urine rather than reabsorb it into the blood stream. This is caused by a component of the kidney, called the distal convoluted tubule, being either absent or very underactive.
Significant amounts of salt and potassium are lost in the urine and this can affect muscle function and energy levels. However, symptoms may not be obvious or particularly troublesome during childhood.
Patients with Gitelman’s syndrome may first seek medical advice during their adolescent or teenage years, when they are feeling more lethargic and tired than their peers. An associated finding is that this condition tends to cause blood pressure to be abnormally low.
People with this condition have been born with it. Our bodies have two copies of every gene and parents will each pass one of their own pair of genes on to their children.
If they are both carriers of Gitelman’s syndrome they will have one affected gene and one unaffected. Their children will have a one in four chance of inheriting the affected gene from both parents. However, if one parent has the condition and the other neither has it nor is a carrier, their children will not inherit it.
Patients are referred by their GPs when their blood tests demonstrate low potassium and low magnesium, accompanied by clinical signs of lower than average blood pressure and excessive tiredness. At their first consultation in hospital, arrangements will be made for them to undergo genetic testing for Gitelman’s syndrome.
It is treated with supplements of potassium and magnesium in tablet form. In addition, Amiloride or Triamterene are often prescribed, as they encourage the body to hold on to the sodium and potassium salts which would otherwise be lost in excess.
This is probably the only condition where doctors would encourage a liberal amount of salt to be added to the diet. Patients are also encouraged to eat fruits and vegetables that are high in potassium, among which are bananas, avocado pears, sweet potatoes and spinach. Coconut water is also rich in potassium.
Most patients with Gitelman’s syndrome choose to be reviewed as hospital out patients on an annual basis, since their condition is unusual and they like to keep in touch with a specialist to discuss any concerns. Care between these visits is normally at the GP’s surgery.