I am a 70 year old board certified otolaryngologist who retired with bad knees and osteoarthritis. I use a cane in order to walk with the bad knees. I am 5' 7" in height and weigh usually about 179#. I had some 2-3+ pre-tibial swelling of my lower legs with increased weight to 185#. My vascular physician explains I have incompetent valves in my superficial leg veins. He gave me Lasix 20mg tabs to use when the swelling becomes troublesome. Because the Lasix diuresis lowers the blood levels of potassium, I was given potassium chloride 20 meq ER to take when I use the Lasix. On Sunday 12/27 6AM I took 10 Lasix tabs and within 6 hours I had diuresis of 9 pounds of fluid. I had no troubling symptoms until 48 hours later when I had sudden moderate muscular cramping pain in my right deep buttock pushing into my right hip and 30 minutes later was causing similar pain in the posterior thigh deep to the femur. At this time I did not suspect any relationship of these symptoms to the diuresis. Calling my orthopedist, he advised local heat for 5 minutes followed by ice for 30 seconds, then repeat as needed. There was some benefit. The next day the area was quite sore which I treated with Naproxen 550mg PO. Last night I went to the movie theater to see Star Wars and while sitting comfortably without moving much, was nearly 2 hours into the movie when I had sudden severe muscular spasm of what felt to be my entire right thigh. I was forced out of my seat with great pain. I slowly and painfully walked in the halls. At about 5-10 minutes the spasm loosened up and the pain decreased from severe to moderately severe. When I got home, the pain was lessened so I could think about the possible causes.
My best analysis of all I have shared above with you is a diagnosis of hypokalemia. Since the diuresis 5 days ago, I have taken 7 tabs of potassium chloride 20 meq ER. I thought that my sitting on my right hip and thigh without moving much for nearly 2 hours may have predisposed these muscles to have a lower potassium level than when walking and moving, thus making them more susceptible to severe spasm while leaving the other muscle groups alone.
Questions: Do you like my diagnosis? If not, what you think? What do you advise? Should I continue taking the KCl?

PS: The only place in Chico California where I can get a complete metabolic blood panel and electrolytes until Monday is thru the ER in Enloe Hospital with a minimum of 3 hours wait. If you would order the blood tests for me at Enloe Laboratory (530) 332-7360, I would go there now for the results.
You have my deepest gratitude for your kindness in considering my medical condition.
Larry R Bartschi, MD
530-894-6000
Fax 530-894-6009