Sodium- and chloride values not clear

Question

Our 16-year-old daughter had a sweat test done, because her height is only 1.48 cm (I myself have only 1.56cm height). The sodium value was 68 and the chloride value 39. We have had these values alreday for the second time. She however does not have any symptoms, in spite of panic attacks with dyspnea from time to time. Half a year ago, the pancreas has been investigated, the values were super. And x-ray of the lung had been done and this was not suspicious, they said that this however has no meaning.
Are there other reasons why these values are increased? The physicians do not seem to be too worried, however, me and my daughter, we are!
Best regards,

Answer

Dear questioner,
thank you for your request. The sweat test of your daugher has definitely not a clear pathologic result. The chloride values is borderline (norm: chloride smaller than 30 mmol/l, borderline area between 30 and 59 mmol/l, pathological (=speaks for CF) 60 mmol/l or over 60 mmol/l). For making the diagnosis of CF, only the chloride value is accepted. It is very important, that the test has been done at a certified CF-center and the chloride value was measured by the so-called "pilocarpine ionotophoresis". If this was not the case, it should be repeated at such a center.
A borderline sweat test can occur in case of malnutrition of all sorts. Please talk to your pediatrician, if there are any signs for that in your daughter.
Furthermore it shoudl be clarified, if other reasons (i.a. atopic eczema, insufficiency of the adrenal gland, byler's syndrome (=progressive, familiar intrahepatic cholestasis), glycogenosis, hypoparathyreoidism, mucopolysaccharidosis, nephrogenic diabetes insipidus) than CF might be underlying, that also have an increased chloride value in the sweat.
If I understand you right, the sweat test had been done, because your daughter is smaller than you. The height of the father would be important, in order to determine the inherited target value of height. The inherited target value can be calculated for your daughter from your height and the height of the father divided by two and minus 6.5 cm; than +/- 8cm.
(example: mother 156cm, father 165cm, inherited target area of height of your daughter: 156cm + 165cm devided by two = 160.5 cm; minus 6.5 cm = 154 cm +/- 8cm, therefore 146cm-162 cm. Than your daughter would still be in the lower range of the target height.
There are many reasons for the height of your daugher. An x-ray of the hand would be important, to see, if your daughter is still growing or not. Probably your daughter is only developing late, and the bones have not reached their full growth yet. Please discuss with your pediatrician an investiagtion respectively an investiagtion at a specialized department (pediatric endocrinology).
Also, the reasons for her panic attacs with dyspnea have to be identified. Are these occuring during sleep, she might have stops of breathing during sleep. Then an investiagion in the sleep laboratory would be helpful.
If the problems occur during the day, these things should also be discussed: young women develop sometimes cramps of the vocal cord, a so-called vocal cord dysfunction. As reasons, reflux of acid gastric fluid on the vocal cord or emotional stress are discussed. Both can be treated, the first by acid blocker drugs, the second by learning how to relax. The diagnosis can be made by endoscopy of the larynx. If not yet happend, please contact a psychologist.
It seems to be importand to find out the reason of the symptoms small height and panic attacs. If no signs of CF or airway symptoms can be found or a malnutrition (with impaired absorption of the nutrients from the gut), a borderline sweat test should not worry you. In case the physicians suspect CF, one can do an genetic investiagation.
I hope to have helped you further,
Best regards,
PD Dr. Sabina Schmitt-Grohé

03.04.2017