Subcutaneous heparin is commonly used for prophylaxis of deep vein thrombosis. Heparin induced hypoaldosteronism can lead to hyperkalemia and natriuresis. These side effects are more common in elderly, renal insufficient and diabetic patients. We present a case with heparin induced hyperkalemia in a patient with diabetes.
An 85 year old lady with insulin dependent diabetes mellitus of 32 years duration with peripheral neuropathy was admitted under the vascular surgeons with extensive gangrene and ulceration of the left lower limb and an ulcer of the right foot. Initial investigations were as follows:
Hb- 93gm/l ; WBC 11,900 ; PLT 609,000 ; INR 1.3 ; APTR 1.43 ; Na 133 mmol/l K 4.5mmol/l ; Creatinine 82 micromol/l .
She was treated with broad spectrum antibiotics and started on unfractionated heparin 5000u sc twice daily. she required a left below knee amputation . Three days later she developed chest pain and shortness of breath.
Arterial blood gases: ph 7.43, Pco2 5.11, Po2 9.32, Hco3 25.6mmol/l,
Glucose 15.3mmol , lactate 0.9mmol/l, Na 123mmol/l, K 6.1mmol/l. Despite active management of her hyperkalemia, it persisted. Short Synacthen test was normal . Urine:ph 5.2 , Na 69mmol, k 24mmol, osmolality 438millosmols/kg .
Plasma renin 21.5mu/l (5-47mu/l), aldosterone 2.7ng/l (10-160ng/l).
Her heparin was stopped because of hyperkalemia and 3 days later her serum electrolytes were Na132mmol/l, k 4.7mmol/l.
Subsequently while still awaiting a femoral artery/ anterior tibial by-pass graft she again developed chest pain, shortness of breath and was restarted on low molecular weight heparin. Two days later her, serum electrolytes were as follows:
Na136mol/l, k 5.80mmol/l, urea 19mmol/l, creatinine 118micromol/l.
ABG: ph 7.34, Pco2- 5.94, P02- 5.02, Hco3 23.4mmol/l, Be -0.8. V/Q scan and spiral CT chest showed no evidence of pulmonary emboli and heparin was stopped.She was discharged home after operation with plasma: Na 135mmo/l, K 5.20mmol/l, creatinine 135micromol/l, aldosterone 57ng/l, renin 73mu/l.
At outpatient follow up, her serum Na 135mmol, k 4.40mmol/l,
Aldosterone 123ng/l (10- 160ng/l).