66 y/o f with long history of Sjogren’s syndrome and RA presented with hypokalemia, hyponatremia and metabolic alkalosis. She had a TTKG> 10 when her K was 2.9 indicating K wasting. She had normal calcium level and magnesium level. Aldosterone level was elevated and Plasma renin activity was not suppressed.
24 hour urine K was increased and calcium was pending.
We suspected Gitelman syndrome!
I was very hesitant to agree with this diagnosis given the age of onset of symptomatology and the long history of Sjogren syndrome. A diagnosis which will go with her history of autoimmune disorder would have made more sense.
On reviewing Sjogren syndrome related hypokalemia, I understood that,
1) SS can lead to Type 1 RTA (hypokalemia and acidosis) – However, the pt had alkalosis and not acidosis
2) SS can lead to Na wasting and this subsequently leads to K wasting in principle cell(in exchange for sodium). This mechanism is entirely different from RTA
3) Autoantibodies targeted against NCC and subsequently leading to Aquired Gitelman syndrome.
Well, the third possibility sounds reasonable in this clinical setting!
Follow the link to study more about aquired Gitelman in Sjogren syndrome
Update from commentary section
There are other references for the aquired Gittelman Syndrome which I am presenting below.