CKD & High Uric Acid

CKD & High Uric Acid:

CKD causes high Uric acid due to reduced filtration and tubular excretion. High Uric acid due to CKD usually doesn’t cause gout (due to coexisting acidosis of renal failure which makes Uric acid soluble).

Hyperuricemia due to other cause can lead to renal failure by stones, TIN (Tubulointerstitial Nephritis), ATN and nephrocalcinosis. High Uric acid level in blood correlates with renal involvement (but doesn’t always correlate with joint disease). So higher is serum Uric acid, higher is chance of renal failure. Lowering Uric acid level helps save kidneys.
High Uric acid is also associated with pre-eclampsia, metabolic syndrome and HTN which may also contribute to renal disease.

Diuretics, often needed in renal diseases for controlling water and electrolytes, cause hyperuricemia by increasing reabsorption at proximal tubules ( as hypovolemia reduces GFR and hence increase reabsorption at PCT via Tubuloglomerular feedback) and can make things worse. Diuretics often can’t be avoided so patient will need urate lowering therapy if indicated.

Any urate level above normal level if thought to be the cause of renal disease, needs treatment irrespective of the fact “how high it is” and even if it’s “not so high”. Keep it as low possible. Renal involvement, tophi, recurrent gout or urate level 13mg are indications for treatment.

Uricosuric drugs (Probenecid etc) can’t be used to lower down serum level of Uric acid if kidneys are already involved or 24 hour urinary urate level is 8mg or more. Febuxostat and Allopurinol can be used in CKD and later one may need dose adjustments according to GFR. Steroids (systemic and /or intra articular) are safe to treat gout if patient has CKD. Colchicine isn’t a safe option especially when GFR is less than 30 as it accumulates and can cause fatal toxicity such as Neutropenia etc by marrow suppression as it blocks cell division and cell migration through microtubules inhibition.
NSAIDs are absolutely contraindicated in any renal disease.

ACUTE EPISODE of GOUT IN CKD:
During acute attack of gout in patients with CKD , if gout is limited to 1-2 joints, intra articular steroid injection would be much useful n safe option.
If it’s polyarticular, avoid colchicine & NSAIDs.
Use systemic steroids with adjusting dose of antidiabetic medications. Intermediate acting insulin such as NPH is best to control steroid induced hyper glycemia.
Renal dose of allopurinol can be added once inflammation is controlled or steroids are on board.
Febuxostat is alternate to Allopurinol if later can’t be used.

Any thing more than that, refer to Rheumatology for other options such as pegloticase or IL-1 blocker (Analinra etc).