Repeat imaging for intracranial aneurysms in patients with autosomal dominant polycystic kidney disease with initially negative studies: a prospective ten-year follow-up.

Patients with autosomal dominant polycystic kidney disease (ADPKD) have a higher incidence of intracranial aneurysms (ICA) than the general population. These ICA also rupture at an earlier age in patients with ADPKD and are associated with high morbidity and mortality. In a recent study, 25% of patients with ADPKD with a documented ICA demonstrated a new ICA on follow-up. It is not known, however, whether patients with ADPKD who have had a negative ICA imaging study would demonstrate an ICA on a repeat imaging study. Only 2 (2.6%) of 76 patients with ADPKD with an initially negative study demonstrated an ICA on follow-up, despite the high frequency of risk factors such as hypertension, smoking, and a family history of ruptured ICA. The mean length of follow-up was 9.8 yr (median, 9.7 yr). These findings have important health care and economic implications in following patients with ADPKD.

Hyperkalemia with concomitant watery diarrhea: an unusual association.

Four patients presented to the emergency room with life-threatening hyperkalemia and concomitant watery diarrhea. Hypovolemia, acidosis, and renal insufficiency were present in all 4 cases. In 2 patients, hyperkalemia followed initiation of angiotensin-converting enzyme (ACE) inhibitor therapy, whereas 1 patient experienced hyperkalemia after a dose increase of an ACE inhibitor, and the fourth patient was on continuous ACE-inhibitor therapy at the time of the hyperkalemia episode. Two of the 3 patients with functioning kidneys required hemodialysis to correct the hyperkalemia, whereas the other patient was on long-term hemodialysis therapy. In the 2 patients in whom transtubular potassium (K+) gradients were available, their values ranged far below normal, indicating tubular failure to secrete K+. This abnormality was attributed to decreased distal delivery of sodium and water and to renin/angiotensin II/aldosterone blockade. It has been proposed that aldosterone blockade impairs the capacity of the colonic epithelial cells to secrete K+. In all 4 patients the watery diarrhea ceased in parallel with the correction of serum K+ to normal values. It is suggested that hyperkalemia, most likely by stimulating intestinal motility, induced the watery diarrhea in all 4 patients. The watery diarrhea, however, failed to compensate for the renal tubular failure to secrete K+.

Recurrence of intracranial aneurysms in autosomal-dominant polycystic kidney disease.

BACKGROUND: The natural history of intracranial aneurysms (ICAs) in individuals with autosomal-dominant polycystic kidney disease (ADPKD) is poorly defined. METHODS: We followed twenty ADPKD subjects, eleven with ruptured and nine with intact ICA, for 15.2 +/- 8.1 years (range, 6.0 to 33.2 years). Initial diagnosis was by four-vessel cerebral angiography in eighteen subjects. Follow-up examinations were four-vessel cerebral angiography in fourteen and magnetic resonance angiography (MRA) in six subjects. We examined the occurrence of new ICAs, an increase in size of existing ICAs, recurrent rupture or surgical intervention, and death. RESULTS: Age at initial diagnosis of ICA was 37.7 +/- 10.4 years (range, 20.2 to 53.1 years). Seventeen subjects (85%) had an anterior and three (15%) had a posterior ICA at initial diagnosis. On restudy, five subjects (25%) had a significant change, consisting of new ICAs in a different location in all five and an increase in size of an existing ICA in two of the five. All subjects with ruptured ICA and one subject with intact ICA had undergone surgery at the time of initial diagnosis. Ten subjects (50%) underwent further surgery 8.1 +/- 6.1 years later (1.3 to 17 years). No subject died during follow-up and one subject experienced a recurrent RICA (RICA). We were unable to identify risk factors associated with development of a new ICA or increase in size of an existing ICA. CONCLUSION: Individuals with ADPKD and ICA appear to be at moderate risk for new ICAs and increase in size of existing ICAs; mortality and risk of recurrent rupture, however, appear to be low.