Usefulness of Magnetic Resonance Imaging in the Diagnosis of Juxtaglomerular Cell Tumors: A Report of 10 Cases and Review of the Literature.

Juxtaglomerular cell tumors (JCTs), a rare but potentially curable cause of hypertension, are difficult to diagnose because they may be missed or misidentified as a cyst by computed tomography (CT). Their magnetic resonance imaging (MRI) pattern has not been well described. We report the clinical, biological, and radiologic features of 10 patients with JCTs. Eight were women, and median age was 24.5 years. All had severe hypokalemic hypertension related to marked secondary hyperaldosteronism. Median plasma renin and aldosterone concentrations were 392 (minimum-maximum [min-max], 70.5-4,800) mIU/L and 1,490 (min-max, 671-2,492) pmol/L, respectively. Plasma prorenin concentration was 835.5 (min-max, 133-6,546) mIU/L. Median tumor size was 17.5mm. On CT, JCTs were spontaneously isodense, with little enhancement after contrast media injection. On MRI, JCTs were iso- (7/10) or hypointense (3/10) on T1-weighted images (WIs). On T2-WIs, JCTs were hypointense (2/10), isointense (4/10), or heterogeneously hyperintense (4/10). A thin peripheral "pseudo-capsule" (hypointense on T2-WIs) was observed in 6 of 10 cases. Contrast enhancement was low, slightly heterogeneous, and delayed. On diffusion-WIs, tumors were hyperintense with a restricted apparent diffusion coefficient. When hypertension with secondary hyperaldosteronism remains unexplained after CT, MRI of the kidney should be considered, especially for young women.

Nephropathy in Townes-Brocks syndrome (SALL1 mutation): imaging and pathological findings in adulthood.

BACKGROUND: Townes-Brocks syndrome (TBS) is a rare autosomal dominant disease, resulting from mutation in the developmental gene SALL1. The phenotype encompasses malformations of limbs (triphalangeal thumbs and pre-axial polydactyly), intestine (anal stenosis) and ears (dysplastic ear with perception hearing loss). Renal involvement (hypo-dysplasia, multicystic kidneys or unilateral absence) is observed in almost half of patients and may progress to end-stage renal failure in childhood. METHODS: Herein, we report two adult patients diagnosed with TBS at age 28 and 35. RESULTS: Both exhibited severe chronic renal failure and kidney hypodysplasia by imaging studies while focal and segmental glomerulosclerosis (FSGS) was demonstrated in one case. CONCLUSION: Regular assessment of glomerular filtration rate is mandatory throughout life in all TBS patients.

[The effect of angiotensin-converting enzyme inhibitors on the progression of chronic renal failure]. / Action des inhibiteurs de l'enzyme de conversion sur l'évolution de l'insuffisance rénale chronique.

SEVERAL MECHANISMS: The progression in renal failure first implies hemodynamic mechanisms and among which angiotensin II has a central role, but also an increase in proteinuria and the induction of many inflammatory and mitogenic mediators that enhance fibrosis (TGF-beta), an effect stimulating the thrombotic mechanism. Among these factors of progression in renal failure, hypertension and proteinuria are the two major factors. Proteinuria is "nephrotoxic" and leads to glomerular and tubulo-interstitial lesions. THE ROLE OF ANGIOTENSIN-CONVERTING ENZYME INHIBITORS: Angiotensin-converting enzyme inhibitors (ACE) affect the different mechanisms that lead to glomerulosclerosis: antihypertensive effect, with the normalisation of blood pressure having demonstrated its determining role in the production of nephrosis in various epidemiological studies; hemodynamic effect with a decrease in glomerular capillary pressure, in the filtration fraction, and inhibition of the bradykinin deterioration; antiproteinuric effect superior to that of other anti-hypertensive drugs (excepting angiotensin II-receptor antagonists). Two indications ACE inhibitors have demonstrated their efficacy in slowing the progression of renal failure in two large pathological fields: diabetic nephropathy in which this effect is demonstrated in type I diabetes, although the results are not as obvious in type II diabetes in which the nephropathy is multi-factor. The recent French and American recommendations are that ACE inhibitors should be used in first intention in diabetic nephropathies and aimed at tight blood pressure control; non-diabetic nephropathies Two pivotal studies have demonstrated the efficacy of ACE inhibitors in nephropathies whatever their type. These data have led to propose ACE inhibitors in first intention in patients exhibiting chronic nephropathies, whether hypertensive or not THE COMBINATION WITH OTHER HYPERTENSIVE DRUGS: Calcium channel blockers have a beneficial trophic effect in renoprotection and can be combined with ACE inhibitors, particularly in the case of diabetic nephropathies. ACE inhibitors and angiotensin II-receptor antagonists have comparable effect on hemodynamics and glomerulosclerosis factors. Clinically, the decrease in proteinuria is identical. Endothelin antagonists have also been studied in renoprotection and appear to have a beneficial effect when combined with ACE inhibitors. GLOBALLY: ACE inhibitors remain the only treatment with demonstrated long-term efficacy in the progression of chronic renal failure. However, the concept of renoprotection needs to be widened to all the factors implied in the progression of chronic renal failure, and ACE inhibitors only represent one aspect of treatment. The role of angiotensin II-receptor antagonists, alone or combined, is clearly promising.

Acute renal infarction: a case series.

BACKGROUND AND OBJECTIVES: Renal infarction is an arterial vascular event that may cause irreversible damage to kidney tissues. This study describes the clinical characteristics of patients with renal infarction according to underlying mechanism of vascular injury. DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS: This study retrospectively identified 94 patients with renal infarction diagnosed between 1989 and 2011 with the aim of highlighting potential correlations between demographic, clinical, and biologic characteristics and the etiology of renal infarction. Four groups were identified: renal infarction of cardiac origin (cardiac group, n=23), renal infarction associated with renal artery injury (renal injury group, n=29), renal infarction associated with hypercoagulability disorders (hypercoagulable group, n=15), and apparently idiopathic renal infarction (idiopathic group, n=27). RESULTS: Clinical symptoms included abdominal and/or flank pain in 96.8% of cases; 46 patients had uncontrolled hypertension at diagnosis. Laboratory findings included increase of lactate dehydrogenase level (90.5%), increase in C-reactive protein level (77.6%), and renal impairment (40.4%). Compared with renal injury group patients, this study found that cardiac group patients were older (relative risk for 1 year increase=1.21, P=0.001) and displayed a lower diastolic BP (relative risk per 1 mmHg=0.94, P=0.05). Patients in the hypercoagulable group had a significantly lower diastolic BP (relative risk=0.86, P=0.005). Patients in the idiopathic group were older (relative risk=1.13, P=0.01) and less frequently men (relative risk=0.11, P=0.02). Seven patients required hemodialysis at the first evaluation, and zero patients died during the first 30 days. CONCLUSIONS: This study suggests that the clinical and biologic characteristics of patients can provide valuable information about the causal mechanism involved in renal infarction occurrence.