Calcium-sensing-related gene mutations in hypercalcaemic hypocalciuric patients as differential diagnosis from primary hyperparathyroidism: detection of two novel inactivating mutations in an Italian population.

BACKGROUND: Inactivating mutations of the calcium-sensing receptor (CaSR), of the G-protein subunit α11 (GNA11) and of the adaptor-related protein complex 2, sigma 1 subunit (AP2S1) genes are responsible for familial hypocalciuric hypercalcaemia (FHH). The aim of this study was to analyse prevalence and pathogenicity of CaSR, GNA11 and AP2S1 mutations in patients with an FHH phenotype and to compare them with a sample of patients with primary hyperparathyroidism (PHPT) in order to identify the most useful laboratory parameter for a differential diagnosis. METHODS: Patients with an FHH phenotype were studied with polymerase chain reaction amplification and direct sequencing of the entire CaSR, GNA11 and AP2S1 coding sequences. Novel mutations were introduced in a Myc-tagged human wild-type (WT) CaSR cDNA-expressing vector, and functional assay was performed on human embryonic kidney cells evaluating expression and function of mutated proteins. RESULTS: Among 16 FHH patients, none had an inactivating GNA11 or AP2S1 mutation while 3 (18.8%) carried a CaSR mutation and 10 (62.5%) at least one CaSR polymorphism. Within the latter group, 7 of 10 patients had more than one polymorphism (4.1 ± 2.1 per patient). Two novel CaSR mutations [c.2120A>T (E707V) and c.2320G>A (G774S)] were identified: the E707V mutation prevented CaSR expression (western blot), whereas the G774S mutation determined a reduced receptor sensitivity to calcium (IP3 assay). PHPT patients showed significantly (P < 0.001) higher serum calcium, parathyroid hormone, urinary calcium and calcium-creatinine clearance ratio (CCCR) and significantly lower serum phosphate than FHH ones. CONCLUSIONS: FHH should be clearly differentiated by PHPT to avoid unnecessary surgery: CCCR could be a useful screening tool while genetic analysis should include the two novel CaSR mutations herein described. The role of multiple polymorphisms deserves further investigation in patients with an FHH phenotype.

[Monocentric experience of left atrial appendage occlusion among patients with advanced chronic kidney disease and non-valvular atrial fibrillation].

Atrial fibrillation is the most common cardiac disorder among chronic nephropathic patients. Possible therapeutic approaches include the use of anticoagulants, which are able to reduce the risk of thromboembolism but lead to an increasing bleeding risk, especially in this cohort of patients. Also, novel oral anticoagulant agents (NAO), due to their mainly renal clearance, are a relative contraindication in advanced renal disease. As an alternative to the oral anticoagulant therapy, left atrial appendage occlusion seems a promising opportunity in high risk, difficult to manage patients. Since there is limited evidence of LAAO in advanced chronic renal disease or dialysis patients, we report here a monocenter experience on 12 patients (6 of which in regular dialytic treatment) with a median clinical follow-up of fourteen months (3-22 months).

[Preliminary report on the Covid-19 outbreak in Valle d'Aosta dialysis centers].

Valle d'Aosta, Italy's smallest region, faced a Covid-19 epidemic trend of absolute relevance. In line with data concerning the local general population, the predominance of the illness among uremic patients has been high. The authors report here preliminary data on the spread of this disease within the region and on the clinical trend of the infected patients who needed to be hospitalised.

[Monoclonal gammopathy of renal significance and membranoproliferative glomerulonephritis: a complex relationship with promising therapeutic opportunities].

In the last few years, the increasing awareness of the complex interaction between monoclonal component and renal damage has determined not only a new classification of the associated disorders, called Monoclonal Gammopathy of Renal Significance (MGRS), but has also contributed to emphasize the importance of an early diagnosis of the renal involvement, which is often hard to detect but can evolve towards terminal uraemia; it has also pointed at the need to treat these disorders with aggressive regimens, even if they are not strictly neoplastic. The case described here presented urinary abnormalities and renal failure secondary to a membranoproliferative glomerulonephritis (MPGN), with intensively positive immunofluorescence (IF) for monoclonal k light chain and C3, and in the absence of a neoplastic lympho-proliferative disorder documented on bone marrow biopsy. After the final diagnosis of MGRS, the patient was treated with several cycles of a therapy including dexamethasone, cyclophosphamide and bortezomib, showing a good functional and clinical response.

[Severe multifactorial hyponatremia]. / Severa iponatremia a genesi multifattoriale.

Hyponatremia is the most common electrolyte disorder observed in hospitalized patients. The most severe forms are neurological and potentially fatal emergencies; yet increased morbidity, length of hospital stay and costs associated with less severe forms are aspects of major concern. Nephrologists are frequently consulted regarding the therapeutic management and the key pathophysiological issues of hyponatremia, as this latter aspect represents a true challenge in an emergency setting. We report a case of a woman admitted to the emergency room for gait instability caused by a very severe multifactorial hyponatremia with a favourable clinical outcome.

[What if it is not an acute pyelonephritis? A monocentric experience of renal infarcts]. / Quando non è una pielonefrite acuta: esperienza monocentrica di infarti renali.

BACKGROUND: Often the reduced contrast enhancement on CT renal imaging is radiologically interpreted as acute pyelonephritis (PNA), but it is the task of the clinician to assess a possible differential diagnosis such as a renal infarct and look for a cause. METHODS: In our experience (2010-2013), we hospitalized 51 patients with radiological imaging consistent with acute pyelonephritis in native kidneys. However, three of these cases result, after a second look, to be ischemic lesions, only sometimes complicated by over-infections (Tabella 1). FIRST CASE: a woman hospitalized for fever and flank pain with blood culture positive for Klebsiella Pneumoniae. Antibiotic therapy allowed a clinical-laboratory improvement, but after 45 days persisted a focal wedge to the CT scan. The labs showed a anemia due to a sickle cell disease (SLC). The overview was finally interpreted as a renal infarct secondary to a sickle cell anemia, initially complicated by over-infection. SECOND CASE: a men hospitalized for a acute flank pain. The CT scan showed a left renal infarct and a partial renal artery thrombosis, resulting in abuse of cannabinoids and LAC positivity.Third case: a woman hospitalized for flank pain and slight movement of inflammatory markers. CT showed a cuneiform area in the right kidney not vascularized, that did not resolved after prolonged antibiotic therapy. The labs evidence a heterozygous mutation of prothrombin and MTHFR causing the renal infarction. CONCLUSIONS: 6% of radiographic imaging consistent with acute pyelonephritis concealed an underlying infarct, due to a unknown state of thrombophilia. The presence of hypovascular imaging to the TC scan, therefore, requires a differential diagnosis between PNA and infarct, especially in the case of atypical development.

[An unusual case of acute aminophylline intoxication]. / Un caso inusuale di intossicazione acuta da aminofillina.

Theophylline/aminophylline use for asthma and chronic obstructive pulmonary disease has declined over time, as new and safer therapies developed. However, theophylline/aminophylline overdose can occur. Hereby it is described an unusual case of severe aminophylline intoxication due to mesodermic injections treated with CVVHDF session.

[Acute pielonephritis and renal abscesses in Piedmont and Aosta Valley]. / Indagine sulla pielonefrite acuta e sugli ascessi renali in Piemonte e Valle d'Aosta.

The Piedmont Group of Clinical Nephrology compared the activity of 18 nephrology centers in Piedmont and Aosta Valley as regards acute pielonephritis (APN). Data from more than 500 cases per year of APN were examined. The microbial spectrum of APN consists mainly of Escherichia coli and Klebsiella pneumoniae. Diagnosis was based on both clinical and radiological criteria in most of the centers (computed tomography-CT o Magnetic Resonance Imaging-MRI). In four centers diagnosis was made with the radiological criteria and in one center only with the clinical features. CT and MRI were performed in about 47% and 44% of cases respectively. Urine culture was positive in 22 up to 100% of cases. The most commonly used antibiotics were fluoroquinolones (ciprofloxacin or levofloxacin) and ceftriaxone (50% of centers) or amoxicillin/clavulanic acid (25% of centers). In 75% of the centers, patients received a combination of two antibiotics (aminoglycoside in 22% of them ). In 72% of the centers, almost 50% of the patients were re-examined, while 38.8% of centers re-examined all the patients. Renal ultrasound was inappropriate to identify abscesses. The mean of patients in whom renal abscesses were detected by CT or MRI was 18.2%. The analysis shows a high variability in the way of diagnosing and treating APN in Piedmont and Aosta Valley regions. This suggests that even if APN is a frequent pathological condition, practical recommendations are required.