Diuretic MAG3 scintirenography in children with HIV nephropathy: diffuse parenchymal dysfunction

HIV nephropathy (HIVN) is prevalent in 15%-56% of HIV-infected children and induces mild to severe progressive nephropathy.

METHODS

A total of 33 renal diuretic scintirenographic studies with 99mTc-mercaptoacetyltriglycine (MAG3) were reviewed and analyzed from 23 HIV pediatric patients, 21 of whom had HIVN with varying degrees of renal impairment. Results were compared with 10 studies of control patients of matching ages. Visual interpretation of images and renograms as well as semiquantitative analyses were performed. Variables compared were size of kidneys, time of peak and one-half peak activities, residual (or retained) cortical activity at 20 min, ratio of cortical activity at 2.5-20 min, and ratio of kidney activity to kidney plus background activity at 2 min. The results of MAG3 renal studies were also compared with laboratory data pertaining to creatinine clearance in all patients and with sonography in 17 patients.

RESULTS

In most patients with HIVN (18/21), the kidneys were larger than normal, with a diffuse parenchymal dysfunction (decreased uptake, slow processing, and increased retention of activity) and flat renograms, findings similar to those observed in other diffuse parenchymal diseases. In all patients with HIVN, semiquantitative analysis (paired t test) showed statistically significant differences from control patients for all variables. On ANOVA, a statistically significant correlation was found between most scintigraphic parameters and the severity of renal impairment. Of the 17 concurrent sonographic studies in HIVN patients, 7 showed no abnormalities, whereas the results of scintigraphy were abnormal.

CONCLUSION

Diuretic MAG3 scintirenography shows nonspecific diffuse parenchymal dysfunction in pediatric patients with HIVN. Such dysfunction may provide corroborative evidence of HIVN and should be recognized when the test is performed for standard indications. Further work is necessary to prove that the test has indeed the high sensitivity and good correlation with the seventy of HIVN suggested in this population; the test may be useful to follow up the progression of disease and the effect of treatment.

ACE inhibition scintigraphy in the management of hypertension in children

Angiotensin converting enzyme (ACE) inhibition scintirenography was performed to help establish the diagnosis and plan treatment of renovascular hypertension (RVH) in 57 hypertensive pediatric patients, 33 infants and 24 children older than 1 year. In 16 of 33 hypertensive infants, ACE inhibition scintirenography established the diagnosis of RVH from renal ischemia (due to aortic or renal arterial thrombi). Two scintigraphic criteria were used for the diagnosis of RVH: criterion I, ischemic and damaged kidney (a non-functioning kidney on or off ACE inhibition) and criterion II, ischemic but not damaged kidney (ACE inhibition induced deterioration of function of the kidney). When criterion I was present and the contralateral kidney was normal, ACE inhibitors could be used for treatment of hypertension without deterioration of renal function; kidneys satisfying criterion I eventually involuted or manifested growth arrest and frequently caused persistent RVH, even after resolution of the thrombus, requiring nephrectomy. When criterion II was present bilaterally, or it was associated with criterion I contralaterally, the use of antihypertensive drugs other than ACE inhibitors was necessary in order to prevent renal insufficiency or failure from ACE inhibitors. However, kidneys with criterion II showed normal growth and, following retraction or dissolution of the aortic thrombus, hypertension resolved. In 2 of 24 hypertensive children older than 1 year, the test was diagnostic of branch renal artery stenosis; RVH was cured by selective angioplasty. ACE inhibition scintirenography is useful in the evaluation and planning of treatment in children with hypertension and may predict the outcome of therapy and ultimate renal function.

Fungal peritonitis in pediatric patients

Fungal peritonitis (FP) is a rare complication of peritoneal dialysis (PD). Although treatment with fluconazole (FCZ) has improved catheter survival and preservation of the peritoneal membrane, FP still carries a high morbidity and mortality in pediatrics. High-risk factors for FP include previous usage of systemic antibiotics and recurrent bacterial peritonitis. A prospective experience in the treatment of FP was conducted at the University of Miami/Jackson Children's Hospital from 1992 to 1997. All patients received either oral or intravenous loading dose of FCZ (5-7 mg/kg) followed by intraperitoneal (i.p.) FCZ (75 mg/L). Amphotericin B (amp B) was added when clinical sepsis was present. A total of 6 patients had FP (all Candida sp.; mean age: 6 years). Two of these patients were neonates with Tenckhoff-catheter placement at less than 1 week of age. Five patients achieved sterilization of the peritoneal fluid. One patient required catheter removal (C. tropicalis). The 2 neonates were infection free for 29 and 41 days, respectively, but both died of superimposed bacterial sepsis. The remaining 4 patients survived and completed 6 weeks of FCZ treatment. Two have had preservation of the peritoneal membrane for more than 1 year. The other 2 were switched to hemodialysis. We conclude that FCZ is an effective treatment for fungal peritonitis in pediatric patients. Adjunct therapy with amp B is usually necessary if sepsis is present. Although eradication of the fungus is possible in a majority of cases, neonates and immunocompromised hosts remain at high risk for morbidity and mortality.