"Are muscle cramps and sleepless nights usual with CKD? And how serious is it if kidney function is at 40%?"
Dr Sarah Jarvis says: "The standard measurement for CKD, or chronic kidney disease, is eGFR, or estimated glomerular filtration rate. The lower your eGFR is, the lower your kidney function. A level over 90 is normal; a level of 60-90 is normal unless you have protein in your urine; 45-59 is ‘stage 3A’ CKD; 30-45 ‘stage 3B’; 15-30 is ‘stage 4’ and below 15 is ‘stage 5’, at which level dialysis is usually needed.
However, these definitions can cause unnecessary worry. For instance, as you get older your eGFR drops naturally. Under the present guidelines, this is classified as chronic kidney ‘disease’, but it’s debatable whether this is really ‘disease’ given that it’s part of the normal ageing process. In fact, it’s only a problem if your eGFR is dropping at such a rate that it’s likely to reach stage 5 during your lifetime. So many of my 80-year-old patients have eGFRs of 45 or 50, but their levels are declining very slowly and I reassure them that it’s unlikely to drop enough to cause them any problems in their lifetime
Unfortunately muscle cramps, which are often worse at night and can disrupt your sleep significantly, aren’t uncommon with CKD. If they suddenly get worse, it is worth seeing your doctor, as this may be due to imbalance of the salts in your blood. They tend to be worse in severe CKD, especially in people on dialysis. Some tablets, including ‘water’ tablets (diuretics), nifedipine and statins (to lower cholesterol) also cause or worsen muscle cramps.
Massaging your legs or applying a warm compress can help. You can try propping your lower legs up on a pillow if you sleep on your back, or hanging your feet over the end of the bed if you sleep on your front. Use a duvet rather than sheets and blankets to prevent them from constricting your feet and causing you to point your toes while you’re sleeping.
Regular stretching exercises can also be very helpful. Some doctors recommend doing them before bed, while others feel that performing them regularly three times a day is more effective. Stand 2-3 feet away from the wall, facing it. Lean towards the wall, keeping your feet flat on the floor. It may be worth a trial of cutting out caffeine and alcohol, too."
-Dr Sarah Jarvis