Creatinine, calcium, citrate and acid-base in spinal cord injured patients

The aim of this work was to recognise factors responsible for reduced citrate excretion, previously reported in patients with spinal cord lesions and possibly related to the occurrence of urinary tract stone or catheter blockage. Inter alia, a reference range for creatinine in plasma (34-88 mumol/l) was also obtained. Two groups of subjects were studied. The first group consisted of 64 male inpatients with spinal cord lesions and 20 male control subjects. The second group were 342 spinal patients who attended an outpatient clinic and 31 control subjects. Plasma calcium was within the normal range but higher in patients within 1 year of onset of the cord lesion than it was later or than was found in control subjects. Plasma pH and bicarbonate were within the normal range but higher in the patients than in the control subjects. When patients with urea-splitting infection were omitted the patients had a higher urinary pH and a lower urinary ammonium than the controls. Urinary and plasma citrate were lower in the patients than in the controls. Urinary citrate was related to urinary potassium and creatinine clearance. Fractional renal tubular reabsorption of citrate did not differ between patients with normal renal function and control subjects. Patients with normal glomerular filtration had lower filtered load of citrate than the controls. The coincidence of relative alkalosis and reduced citrate excretion may be relevant to the understanding of catheter blockage and urinary stone formation in spinal cord injured patients.