NEPHROCALCINOSIS AND PROTEINURIA AS SYMPTOMS OF HYPERTENSION IN AN INFANT

Objective: A case report of a 4-month-old boy with nephrocalcinosis and proteinuria, diagnosed with severe hypertension secondary to middle aortic syndrome (MAS) and bilateral renal artery stenosis. Design and method: A 4-month-old boy was first admitted to the Nephrology Department due to nephrocalcinosis and proteinuria (urinary protein concentration: 28-40 mg/dl; protein/creatinine ratio: 3.3 mg/mg). At diagnosis, in addition to the visualization of several (5-6) calcified deposits in all calyx groups in the right kidney and nephrocalcinosis of the marginal portions of the left kidney pyramids and the diagnosis of hypercalciuria (Ca/creatinine ratio: 2.06 mg/mg), there was an asymmetry in kidney size (73 mm left kidney, 53 mm right kidney). Results: On admission, the patient’s blood pressure values corresponded to stage 2 hypertension and exceeded 95th percentile by 23 mmHg. Further diagnostics, including Doppler examination of the aorta and renal vessels and angio-CT of the abdominal vessels, revealed MAS, bilateral renal artery narrowing, stenosis of the superior mesenteric artery, the visceral trunk, and the left vertebral artery. The effective renal plasma flow of the right kidney in dynamic scintigraphy was 30%. Due to the unfavorable location of the lesions, the patient was disqualified from invasive treatment. Oral hypotensive treatment with amlodipine, propranolol, doxazosin, hydrochlorothiazide, furosemide, and spironolactone was administered. Because of symptoms of left ventricular and left atrial overload (elevated NT-proBNP: 1290 pg/ml), an ACE inhibitor (ramipril) in small dose was added with good effect. A gradual reduction in blood pressure values and reduction in NT-proBNP levels (509.3 pg/ml) were achieved without significant deterioration in renal function. Additionally, there was a reduction in proteinuria (protein/creatinine ratio: 0.99 mg/mg) and normalization of calciuria (Ca/creatinine ratio: 0.09 mg/mg). The patient currently demonstrates good blood pressure control and stable renal function.Figure 1. MAS, bilateral renal artery stenosis, superior mesenteric artery, and visceral trunk stenosis (abdominal angio-CT reconstruction) Conclusions: The case underscores the systemic nature of vascular lesions in fibromuscular dysplasia. It also highlights the initial symptoms (hypercalciuria with urolithiasis/nephrocalcinosis, proteinuria), which were related to pressure diuresis in the course of severe hypertension.