ions exchange

Question

Hello,
my daughter (10 years, suffering from cystic fibrosis) was found during a visit to the emergency (tarchycardia, low grade fever, loss of sight - she saw only black and red, weakness, tremors of the limbs) to have an abnormally low potassium in the blood. Everything was back to normal after perfusion with potassium chloride. I add that we have already "visited" several times the emergencies and pediatric cardiologist for similar symtoms, ECG was normal, my daughter eats fruits and vegetables that contain potassium. I would like to know where this lack of potassium can come from, is it related to the disease and the ion exchange does not work? How to recognize in time this dysfunction (tachycardia is occurring whenever suddenly, but there must be some other signs before?)?

Thank you for your response

Answer

Hello

Potassium in one of the major body cations (positive-charged ion), along with the sodium and the calcium. There are several causes of low potassium (potassium deficiency) in CF:
- The commonest is the excessive loss in sweat.
- Digestive or alimentary troubles can also lead to potassium deficiency: important diarrhoea, repeated vomiting, alimentary troubles as anorexia and bulimia.
- Some drugs could also cause potassium loss. In the general population, the most common medications that cause low potassium are diuretics but they are not frequently prescribed in CF. Other medications, more frequently prescribed in CF, that can have a similar effect are: some antibiotics (tobramycin, gentamicin), insulin, steroids and bronchodilators.

Moderate potassium deficiency can lead to an increased of the heartbeat (tachycardia), fatigue, muscle weakness, muscle pain and cramps, and headaches.

Even with the sweat-loss, potassium supplementation isn’t systematic in CF, as an equilibrated diet usually compensates. However, for your daughter, a potassium enrichment of the diet seems appropriate. Several foods are rich in potassium as fresh and dried fruits, vegetables and fishes. There are many lists of foods that are rich in potassium available on the web, here one of them: www.passeportsante.net/fr/Nutrition/PalmaresNutriments/Fiche.aspx?doc=potassium_nu.



It seams important to discuss the possible causes of potassium deficiency of your daughter with the medical team that follows her regularly, as such as the appropriate diet/treatment. I hope to have responded to your question,

Best wishes

Harriet Corvol

14.01.2013