Renal Function in Primary Hyperparathyroidism

Abstract

Out of 160 consecutive patients operated upon for primary hyperparathyroidism, a follow-up study on renal function could be performed in 139. Clearances of inulin (C_IN) and paraaminohippurate (C_PAH) were determined before and after surgery in 75 of the patients. The average length of postoperative observation was 4.8 years (range 2-11 years) in this group. On average, C_IN and C_PAH were well maintained at the follow-up compared to the preoperative findings. This was true even for the group of patients with abnormal renal function before surgery. Only in two patients was an unequivocal decrease of C_IN demonstrated. In two other subjects, however, serum creatinine showed an increase in the face of equivocal changes in C_IN and C_PAH.

In 64 patients kidney function was evaluated only from the serum creatinine level. The average postoperative period of observation was 5.4 years (range 2-9 years). Renal function had deteriorated in two patients, one of whom suffered from chronic nephritis. Among 13 deceased patients, two had died from uraemia and serum creatinine had increased significantly in a further two.

In summary, a deterioration of kidney function was observed in ten patients. In two of these subjects, however, the cause of the progression of renal damage was uncertain. Except for the patient with nephritis, renal function did not deteriorate but in one patient with a preoperatively normal renal function.

We conclude that, after surgical treatment of hyperparathyroidism, the long-term outcome in terms of renal function may be more favourable than has hitherto been considered. Furthermore, it appears from the present study that the kidney damage in hyperparathyroidism does not deteriorate after surgery unless complicating factors exist, e.g. chronic urinary tract infection with destructive uro-graphic changes and/or severe hypertension.