Ps-c26-6: hypertension due to hydronephrosis secondary to igg4-related disease

Background: Immunoglobulin G4-related disease (IgG4-RD) is an immune-mediated fibroinflammatory condition that is capable of affecting multiple organs. It can present as an inflammatory pseudotumor in various organs. Patients may present with normo- or hypertension (HT) and urinary tract obstruction (UTO). Hydronephrosis (HN) leads to HT by overloading vessels or activating the renin-angiotensin system. Case presentation: A 53-year-old man presented with a two week history of abdominal pain. At admission, his blood pressure (BP) was 208/112 mmHg. His physical examination was otherwise unremarkable. Laboratory data and imaging revealed post-renal azotemia. HN was identified due to a mass around the aorta causing bilateral ureteric compression. The right ureter was considered to be more recently compressed because the left kidney cortex was more extensively thinned compared to the right kidney, respectively. Insertion of a double J stent in the right ureter led to improve urinary output with an attendant reduction of weight of 7 kg. Renal function also improved substantially (serum creatinine 5.66 mg/dL at admission; 1.34 mg/dL post-stent insertion). Initial treatment included intravenous nicardipine, followed oral nifedipine and telmisartan. With the above interventions, HT normalized to 132/71 mmHg in nine days. Finally, only telmisartan was required to maintain normal BP upon discharge. Biopsies of a salivary gland, the lip, and a cervical lymph node were non-diagnostic. The abdominal mass was not biopsied. Urine cytology was negative for malignancy three times. Serum lactate dehydrogenase was within normal limits, whereas soluble interleukin-2 receptor was elevated at 1,730 U/mL. IgG4-RD was considered as the likely cause. In accordance with current international diagnostic criteria for IgG4-RD, there was: 1) no exclusion criteria, 2) elevated serum IgG4 level, 3) hypocomplementemia, and 4) circumferential soft tissue around the infrarenal aorta. Oral corticosteroid therapy was prescribed. At 40 days post-discharge, follow-up imaging showed a slight reduction in the size of the soft tissue mass. Hypocomplementemia also showed improvement. Conclusion: HT was induced by UTO secondary to suspected IgG4-RD. It is reported that HT due to IgG4-RD occur in over one third of cases. Pathophysiology of HT includes renal parenchymal disease and HN. Laboratory data at admission revealed that the plasma renin activity and plasma aldosterone concentration were normal. His BP was ameliorated after urinary output improved, despite using antihypertensive monotherapy. Thus, we suspected that volume overload due to UTO led to HT. We suggest that HN should be considered as a differential diagnosis for the cause of HT.