Doppler visualization of ureteric jets in unilateral hydronephrosis in children and adolescents.

OBJECTIVE: to evaluate Doppler visualization of ureteric jets in the assessment of unilateral kidney collecting system dilatation in children and adolescents. METHODS AND PATIENTS: color Doppler ultrasonography was performed in 27 patients with hydronephrosis (11 female, 16 male, age range 3-21 years, mean age 10.5+/-4.4). Nine had acute obstruction due to ureteral calculus, seven had obstructive hydronephrosis due to uretero-pelvic junction (UPJ) stenosis, and 11 had non-obstructive hydronephrosis. Doppler was also performed in 32 healthy children (15 boys and 17 girls, age 2-17 years, mean age 7.8+/-3.9), who represented the control group. RESULTS: in the control group jets were visible in 57 out of 64 ureteric units (89%). The mean frequency of jets in healthy children was 4.1 jets per min. In all children with hydronephrosis, jets were visible in 25 out of 27 normal ureteric units (92.6%), and their mean frequency was 4.5 jets per min. In children with acute unilateral colic, ureteric jets were completely absent in eight of nine patients (89%). In children with obstructive hydronephrosis, due to UPJ stenosis, jets were absent in five out of seven patients (71.4%), and in children with non-obstructive hydronephrosis jets were absent in three out of eleven patients (27.3%). When jets are visible, their frequencies are much lower on the obstructed side as compared with normal side, while in cases of nonobstructive dilatation frequency of jets is similar on both sides. CONCLUSION: absence of jets in patients with acute obstruction due to ureteral calculus, strongly correlates with high-grade obstruction. In children with UPJ stenosis, presence of ureteric jet does not exclude significant obstruction, but the frequency of jets on the obstructed side is much lower as compared with the unaffected side. When there is absence of jet from the dilated side or significant asymmetry in jet frequency, hydronephrosis is likely to be obstructive.

Hypokalemic metabolic alkalosis--three case reports.

The two most common forms of inherited normotensive hypokalemic metabolic alkalosis are Bartter's and Gitelman's syndromes. Bartter's syndrome typically present with normal or increased calcium excretion. Hypomagnesemia occurs in only one third of affected individuals. In contrast, hypomagnesemia and hypocalciuria are considered hallmarks of Gitelman's syndrome. In most patients, the symptom of muscle weakness and polyuria occur early in life, which may be attributed to potassium depletion. Despite hyperaldosteronism, the patients tend to be normotensive, which is at least explained by vascular hyperresponsiveness to prostaglandins. Therapeutic approaches to Bartter's and Gitelman's syndromes include potassium supplementation, prostaglandin synthesis inhibitors (nonsteroid anti-inflammatory agents), aldosterone antagonists and converting enzyme inhibitors. Three patients with hypokalemia, normal blood pressure, metabolic alkalosis, hyperreninemia and hyperaldosteronism are described. Two patients had Bartter's syndrome and one patients had Gitelman's syndrome.

Renal vascular resistance in essential hypertension: duplex-Doppler ultrasonographic evaluation.

Duplex Doppler ultrasonography has been validated as a noninvasive method to evaluate hemodynamic features of renal blood flow in renal and intrarenal arteries in patients with various renal diseases. The significance of duplex Doppler sonography in the evaluation of renal vascular resistance in essential hypertension has not yet been clearly determined. The aim of the present study was to evaluate the renal vascular resistance in patients with essential hypertension by measuring intrarenal arterial resistance (RI) and to correlate RI with renal functional tests and other clinical and laboratory data. Duplex Doppler ultrasonography was used to measure RIs in intrarenal arteries in 128 patients with essential hypertension and 61 age-matched normotensive control examinees. The renal vascular resistance index (RI) was determined by use of Doppler ultrasound. Hypertension was classified according to the 1997 Joint National Committee Guidelines (JNC-VI). Mean RI in hypertensive patients was 0.66 +/- 0.05 (+/- sd) and in healthy controls 0.60 +/- 0.03 (+/- sd) (p = 0.0001). RI correlated significantly with patient's age (r = 0.577, p = 0.001), duration of hypertension (r = 0.335, p= 0.001), stage of hypertension according to the JNC-VI classification (r = 0.315, p = 0.006), creatinine clearance (r = -0.383, p = 0.001), systolic blood pressure (SBP, r = 0.41, p = 0.001) and mean blood pressure (MBP, r = 0.30, p = 0.002). RI values did not correlate significantly with plasma renin concentration (r = -0.198 NS), diastolic blood pressure (DBP, r = 0.17, p = 0.06), and cardiac pulse (r = -0.10, p = 0.16). Multiple regression analysis showed that independent variables for RI were the patient's age (multiple R = 0.53, signif. F = 0.001) and systolic blood pressure (multiple R = 0.57, signif. F = 0.03). The renal Doppler resistance index (RI) is increased in essential hypertension and it correlates with renal functional tests as well as with patient's age, duration of hypertension, with a stage of hypertension according to the JNC-VI classification, and with systolic and mean blood pressure. The increased renal vascular resistance (RI) in hypertensive patients could be a sign of developing hypertensive nephrosclerosis and consequently renal failure. The utilization of the renal vascular resistance index (RI), provides a new noninvasive parameter in the followup of patients with essential hypertension.