The Clinical Features and Outcomes of Renal Amyloidosis in Tunisia.

Systemic amyloidosis is a rare disease characterized by clinical polymorphism. Indeed, the kidney is the most common organ involved and represents a real turning point in the disease. We aimed to determine the clinicopathological prognostic factors of renal amyloidosis (RA). We conducted a retrospective study including 40 cases with biopsy-proven RA collected in our department over a period of 10 years. Biochemical, demographic, and clinicopathological findings at diagnosis, as well as the follow-up data, were evaluated for each patient. The prevalence of amyloidosis was 2.7 per 100 nontransplant renal biopsies. The mean age at presentation was 55.5 ± 15.6 years with a male-to-female ratio of 1.85. The diagnosis of RA was confirmed by a renal biopsy in 85% of cases. Amyloid A (AA) amyloidosis was the most common type of amyloidosis (65%), and chronic infections ranked first in the panel of etiologies (41%). Amyloid light chain amyloidosis was mainly associated with multiple myeloma (57%). The median patient survival was 59 months versus 12 months for kidney survival. Age and extrarenal localization were independent predictors of mortality, whereas renal failure at presentation significantly influenced renal survival. The results of our study emphasize the rarity but also the severity of RA. AA amyloidosis was the most common type identified, which was mainly caused by chronic infections. Prevention remains the best solution until we can achieve therapeutic advances in inflammatory diseases.

Peritoneal dialysis in Tunisia: complications, technique and patient's survival (twenty-seven years of experience in a single center).

INTRODUCTION: peritoneal dialysis (PD) is a renal replacement therapy method that offers various advantages to end-stage renal disease patients. The aim of our study was to analyze patient characteristics, peritonitis and clinical outcome over a 27-year period of PD in our center. METHODS: retrospective study of incident patients on PD from January 1990 to December 2017. A total of 304 patients were enrolled in the study group. All patients over 15 years of age entering the dialysis program were included in the study. Patients dropping out from PD within three months were all excluded. Biochemical and demographic variables, peritonitis episodes and patient and technique survival were analyzed. RESULTS: the PD prevalence in our center was 4.5% during the study period; the mean age was 46.47 ± 18.6 years; diabetic nephropathy was the main cause of chronic kidney disease: 35.5% (n=108). Cardiovascular disease was the main cause of death: 39.6% (n=34). The peritonitis rate was 0.68 episode per patient-year. Ultrafiltration failure was the most important cause of PD withdrawal: 43% (n=60). Occurrence of peritonitis was the only independent predictor of technique failure: adjusted relative risk [aRR] 5.07, 95% CI 2.69-9.58; p<0.001. The overall non-adjusted patient survival was around 100%, 95% and less than 20% at 1, 4 and 25 years respectively basing on the Kaplan-Meier analysis. The group undergoing renal transplantation had the best survival rate. CONCLUSION: peritonitis remains the most common complication as well as the most provider of technique failure and patient´s transfer to hemodialysis. The technique survival was better in case of absence of peritonitis. However, our series showed the superiority of hemodialysis over PD in terms of overall patient survival.

Hemophagocytic Syndrome in a Pregnant Renal Transplant Recipient Associated With Cytomegalovirus Infection.

Hemophagocytic syndrome is a disorder of the mononuclear phagocytic system resulting in uncontrolled hemophagocytosis and cytokine overproduction. We report the first case of hemophagocytic syndrome, which occurred in a pregnantfemale patient 14 years after kidney transplant who displayed an atypical presentation and who had septic shock following cytomegalovirus infection. The patient, a-39-year-old woman at 27 weeks gestation with end-stage renal disease of unknown etiology, was admitted 14 years after living-donor kidney transplant (donor was her father) with high-grade fever, cough, and pancytopenia. Her immunosuppressant regimen included tacrolimus, azathioprine, and prednisone. Initially, she was hospitalized in the intensive care unit for septic shock without an identifiable focus of infection. She received intravenous broad-spectrum antibiotics before being transferred to our department following optimization of her hemodynamic status. Hemophagocytic syndrome was suspected, and bone marrow aspirate was performed, revealing macrophages with hemophagocytic activity. We confirmed the diagnosis of hemophagocytic syndrome given the presence of more than 5 criteria. We extensively investigated the underlying cause of hemophagocytic syndrome, and we diagnosed cytomegalovirus-induced hemophagocytic syndrome in a pregnant patient receiving immunosuppressive therapy after kidney transplantation. She was treated with corticosteroids and intravenous immunoglobulin. At 31 weeks gestation, she underwent a cesarean section; the baby developed newborn respiratory distress syndrome and died despite adequate resuscitation. We administered ganciclovir for 15 days following an increased cytomegalovirus viral load after delivery, leading to complete recovery.To date, optimal therapeutic and diagnostic guidelines for pregnancy-related hemophagocytic syndrome in female kidney transplant recipients are not well defined, and both patient and allograft survival rates remain low.

Cytomegalovirus Ocular Involvement in a Kidney Transplant Recipient.

Cytomegalovirus remains the most common infection after kidney transplant. We report cytomegalovirus retinitis and anterior uveitis, which developed consecutively within 1 year in a kidney transplant recipient. A 25-year-old man presented 5 months after transplant with decreased visual acuity in his left eye. Fundus examination revealed bilateral areas of necrotizing retinitis with intraretinal hemorrhages. The confirmation of cytomegalovirus disease was based on clinical findings and positive polymerase chain reaction for cytomegalovirus in plasma and in aqueous humor. The patient was treated with intravenous ganciclovir for 21 days and then with valacyclovir for 3 months. The patient's symptoms improved, and fundus examination revealed resolution of retinitis with appearance of retinal scarring. One year later, the patient presented with cytomegalovirus anterior uveitis associated with increased intraocular pressure, which was treated with antiviral agents, antiglaucomatous eye drops, and trabeculectomy. Cytomegalovirus ocular involvement for our immunocompromised patient presented in 2 consecutive forms: bilateral retinitis and anterior uveitis. Early diagnosis and treatment of active cytomegalovirus retinitis and uveitis remain crucial to prevent their progression to irreversible visual impairment.

Mutational Analysis of Agxt in Tunisian Population with Primary Hyperoxaluria Type 1.

BACKGROUND: Primary hyperoxaluria type 1 (PH1) is an autosomal recessive metabolic disorder caused by inherited mutations in the AGXT gene encoding liver peroxisomal alanine:glyoxylate aminotransferase (AGT). PH1 is a clinically and genetically heterogeneous disorder. The aim of our study was to analyze and characterize the mutational spectrum of PH1 in Tunisian patients. MATERIALS AND METHODS: Molecular studies of 146 Tunisian patients suspected with PH were performed by PCR/Restriction fragment length polymorphism (RFLP) to detect seven mutations described as the most common. Direct sequencing for the 11 exons was performed in patients in whom any mutation was not identified. RESULTS: The genetic diagnosis of PH1 was confirmed in 62.3% of patients. The first molecular approach based on PCR/restriction enzyme test was positive in 37.6% of patients, whereas the second molecular approach based on whole gene sequencing was successful in 24% of cases. Twelve pathogenic mutations were detected in our cohort. Two mutations were novel, and five were detected for the first time in Tunisians. The three most frequent mutations were p.Ile244Thr, p.Gly190Arg, and c.33dupC, with a frequency of 43.4%, 21.4%, and 13.1%, respectively. CONCLUSION: The two novel mutations detected in our study extend the spectrum of known AGXT gene mutations. The screen for the mutations identified in this study can provide a useful, cost-effective, and first-line investigation in Tunisian PH1 patients.

BK and JC polyomavirus infections in Tunisian renal transplant recipients.

The aim of this prospective study was to investigate the rate of BK (BKPyV) and JC (JCPyV) polyomavirus infections and their influence on allograft function in Tunisian renal transplant recipients. A total of 72 renal transplant recipients were studied. BKPyV and JCPyV were detected and quantified by real-time PCR in urine and plasma. Demographic and laboratory characteristics were collected for each patient. Polyomavirus DNAuria was detected in 54 (75%) of renal transplant recipients: 26 (36%) had BKPyV DNAuria, 20 (28%) had JCPyV DNAuria, and 8 (11%) had a dual BKPyV/JCPyV DNAuria. BKPyV DNAemia was detected in four (5.5%) patients, whereas no patient had JCPyV viremia. More than 70% of BKPyV and JCPyV infections started within the first 3 months post-transplant. The risk for positive DNAemia was observed in patients with DNAuria level >10(7) copies/ml. BK Polyomavirus-associated nephropathy (BKPyVAN) was observed in two patients. This study highlights the high frequency of BKPyV and JCPyV viruria during the first year post-transplant with the highest incidence observed in the third month. We identified several risk factors that were associated with BKV DNAuria including age, sex of patients, and the use of tacrolimus instead of cyclosporine A at month 3. The use of cyclosporine A instead of tacrolimus was identified as risk factor for JCV viruria in month 3. No statistical difference in the allograft function was found between BKPyV and/or JCPyV infected and uninfected patients.

Development of Limited Sampling Strategies for the Estimation of Tacrolimus Area Under the Curve in Adult Kidney Transplant Recipients According to the Posttransplantation Time.

BACKGROUND: Limited sampling strategies (LSS), using few sampling times after dosing, have been used to reliably predict tacrolimus area under the 12-hour concentration-time curve (AUC). Because the pharmacokinetics of tacrolimus is subject to significant changes over the exposure time to this drug, it can be hypothesized that the reliability of the LSS would also change. This study aimed to develop a reliable and practical LSS allowing the estimation of tacrolimus AUC in Tunisian kidney transplant recipients taking into account the posttransplantation time. METHODS: Thirty Tunisian patients were enrolled into 3 groups (10 in each group) according to the posttransplantation period: period 1: between 1 day and 3 months, period 2: between 3 and 12 months and period 3 over 12 months, as defined by the European consensus conference on the therapeutic drug monitoring of tacrolimus. Samples were collected just before and 0.5, 1, 2, 4, 6, 8, and 12 hours after tacrolimus administration. The full pharmacokinetic profiles obtained from these timed concentration data were used to choose the best sampling times. Error indices (mean absolute prediction error and the root mean squared prediction error) were used to evaluate the predictive performance. RESULTS: Among the 1-point estimations, the C4-predicted AUC showed the highest correlation with the measured one during period 1 and period 2 (r = 0.94 and 0.91, respectively) but not period 3 (r = 0.76). The C0-predicted and the measured AUC become less and less correlated from period 1 to period 3 (r = 0.81, 0.75, and 0.66), respectively. Only the model including the C0/C2 provided a high correlation between predicted and measured tacrolimus AUC regardless of the posttransplant period (r = 0.95, 0.96, 0.98 and root mean squared prediction error = 4.1, 5.8, 4.2 during periods 1, 2, and 3, respectively). CONCLUSIONS: Our data clearly indicate that the predictive performance of LSS is prone to change according to the posttransplantation time. A 2-time point LSS was found to be sufficient to predict tacrolimus AUC. The LSS using C0 and C2 is reliable, accurate, and practical to estimate the AUC of tacrolimus regardless of the posttransplantation time.

Angiogenic activity in the sera of patients with post-kidney transplant erythrocytosis.

Post-kidney transplant erythrocytosis (PTE) is one of the hematological complications in the renal transplant patients. While its pathogenesis still remains to be elucidated completely, a number of therapies are available for the management of PTE. The aim of this prospective study was to investigate whether angiogenesis may be involved in the pathogenesis of post-transplant erythrocytosis by comparing its level with those of different classes of erythrocytosis [polycythemia vera (PV), idiopathic erythrocytosis and secondary erythrocytosis]. The angiogenic activity was evaluated by the assessment of the serum vascular endothelial growth factor (VEGF) levels, as one of circulating angiogenic factor, using a standardized enzyme-linked immunosorbent assay commercial kit in 13 PTE (2 F/11 M), in 75 untreated erythrocytosis non-transplant patients and in 21 healthy subjects controls. The results indicated that VEGF was overproduced in advanced and untreated PV patients and to a lesser degree in idiopathic erythrocytosis thus confirming an increased angiogenic activity. However, there is no evidence of increased angiogenesis in PTE and in secondary erythrocytosis. The absence of angiogenesis in PTE and its presence in PV is another argument that the pathogenesis of these two entities is different.

Cutaneous alternariosis in a renal transplant recipient.

Alternariosis is a fungal infection that is usually described in immunocompromised patients. We report a case of cutaneous alternariosis in a renal transplant recipient caused by Alternaria tenuissima. The diagnosis was supported by histopathologic (ie, yeastlike cells, filamentous structures) and mycologic findings from a cutaneous biopsy. Cutaneous lesions regressed 1 month following a decrease in the dosage of immunosuppressive therapy. The patient also was treated with intravenous amphotericin B followed by oral fluconazole without improvement. Cryotherapy remarkably accelerated healing of the lesions.

Cytomegalovirus ischemic colitis and transverse myelitis in a renal transplant recipient.

We report a rare case of cytomegalovirus (CMV)-associated ischemic colitis and transverse myelitis (TM) occurring precociously after renal transplantation. A 57-year-old male was transplanted with a cadaveric kidney on 5 June 2009. The patient was CMV seropositive and the donor was seronegative. Transplantation was followed shortly by TM, which resulted in paraplegia. The results of magnetic resonance imaging of the spinal cord showed abnormalities. Twenty days after transplantation, he developed abdominal pain with melena and was diagnosed as having CMV-associated ischemic colitis confirmed by colonoscopy and biopsy. Serological data and identification of the viral genome by polymerase chain reaction were confirmatory for CMV. Treatment consisted of intravenous ganciclovir, followed by polyvalent immunoglobulin. The outcome was favorable. Symptomatic CMV infection is relatively common among the renal transplant population. Early colonoscopy is beneficial for making a quick diagnosis and therefore helps to institute a prompt management of CMV colitis. Myelitis is less common in transplant recipients and diagnosis, therefore, was more difficult.

Deafness and blindness in a renal transplant recipient with cryptococcal meningitis.

Infections are a major determinant of outcome in kidney transplantation. Opportunistic pathogens are common in kidney recipients and several organs can be affected. Central nervous system infection in transplant recipients is a medical emergency. There is limited information in the literature concerning post-transplantation cryptococcal infection. Deafness and blindness are not classic findings. We report a case of meningocerebral cryptococcosis complicated by deafness and blindness after kidney transplantation. Physicians need to consider the possibility of Cryptococcus neoformans when symptoms persist despite empiric antimicrobial therapy.

[Post-infectious glomerulonephritis: unusual etiology of postpartum acute renal failure]. / La glomérulonéphrite aiguë postinfectieuse : une cause inhabituelle d'insuffisance rénale aiguë du post-partum.

Severe pre-eclampsia and acute tubular necrosis due to hemorrhagic shock are the major causes of postpartum acute renal failure. Cortical necrosis and haemolytic uraemic syndrome are less frequently. Post-infectious glomerulonephritis as a cause of postpartum acute glomerular disease and renal failure has been rarely reported. We report a patient with postpartum acute glomerulonephritis who presented nephritic syndrome, the diagnosis of which was confirmed by renal biopsy.

Distribution of JC polyomavirus genotypes in Tunisian renal transplant recipients between January 2008 and January 2011.

The polyomavirus JC (JCPyV) is a ubiquitous virus in humans, causing progressive multifocal leukoencephalopathy, a fatal demyelinating disease. JCPyV propagates in the adult kidney and excretes its progeny in urine, from which its DNA can be recovered readily. JCPyV isolates worldwide can be classified into 14 subtypes or genotypes, each associated with a specific geographical region. The European genotypes EU-a-b-c are spread throughout Europe and Mediterranean areas. The major African genotype Af2 is spread not only throughout Africa but also in West and South Asia. A minor African genotype (Af1) occurs in Central and West Africa. Partially overlapping domains in Asia were occupied by various genotypes (e.g., B1-a, -b, -d, B2, CY, MY, and SC). To characterize the subtypes of JCPyV prevalent in Tunisia, the presence of the virus was investigated by real-time PCR in urine samples from 98 renal transplant recipients. For subtype identification, a 610 bp typing region of the JCPyV genome was amplified from each urine sample, and its DNA sequence was determined. In the patients studied, the major African subtype Af2 was the predominant (62.5%), followed by the European subtype EU (33.5%). Only one case clustering with the Asian genotype SC (4%) was identified. The presence of the European subtype with high prevalence in this population suggests that the epidemiological distribution of JCPyV virus sequences in North Africa is related partially to the epidemiological data in Europe.

Brown tumors in dialyzed patients with secondary hyperparathyroidism: report of 16 cases.

Brown tumors (BTs) are relatively uncommon but they are serious complications of renal osteodystrophy. The objective of this study was to analyze the clinical, biological, and radiological characteristics of 16 patients with BTs provoked by secondary hyperparathyroidism (sHPT) and its response to the decrease in parathyroid hormone levels after parathyroidectomy (PTX). The management of that uncommon condition was also reviewed. We conducted a retrospective study including 16 end-stage renal disease patients who underwent subtotal PTX between 1997 and 2007 for severe sHPT with BTs. Our study included 10 men and 6 women, whose average age was 34 years. All patients were on dialysis. Ten of them were on dialysis for more than 5 years. The median duration on dialysis was 84 months. Patients included suffered from swellings associated with functional limitations. BTs had multiple locations in 7 patients. Jaw was the most frequent location (62%). Radiography and tomodensitometry demonstrated a mixed radio lucent and radio-opaque lesions with an expansion of the cortical bone. Bone scan demonstrated an increased uptake of lesions. Chirurgical treatment was indicated in all cases because of severe refractory sHPT with functional limitations and/or disfiguring deformities. In all cases, BTs stopped its progression and even decreased in size. However, it was insufficient in four cases, which required a surgical resection. PTX remains an efficacious approach in resistant cases of sHPT with persistent BTs.

Distribution of BK polyomavirus genotypes in Tunisian renal transplant recipients.

BK polyomavirus (BKV) is a ubiquitous virus in humans that remains latent in the urogenital tract after a primary infection during childhood. The virus, which is reactivated frequently and excreted in urine, can cause nephropathy in renal transplant recipients. BKV sequences are classified into four subtypes (I-IV). Subtype I and IV are divided further into four and six subgroups, respectively. To characterize the subtypes of BKV prevalent in Tunisia, the presence of the virus was investigated by real-time PCR in urine samples from 77 renal transplant recipients. For subtype identification, a DNA fragment in the VP1 coding region, amplified by nested PCR from positive samples, was sequenced and a phylogenetic analysis was performed. In the studied population, subtype I (75.5%), II (14.5%), and IV (2.5%) were identified with a clear predominance of subtype Ib-2 (73%) as observed in European population. This study suggests that in North Africa, the BKV genotype distribution is similar to that of Europe and different from that of sub-Saharan Africa.

Atypical hemolytic uremic syndrome in the Tunisian population.

BACKGROUND: Hemolytic uremic syndrome consists of a triad of acquired hemolytic anemia, thrombocytopenia and renal failure. AIM: Our objectives were to determine epidemiology, clinical and laboratory characteristics of patients with atypical hemolytic uremic syndrome (aHUS) to determine the relationship between the complement protein deficit and aHUS in the Tunisian population. METHODS: We studied retrospectively four cases of atypical HUS in adults admitted in the Nephrology Department of Fattouma Bourguiba Universitary Hospital in Monastir between 2000 and 2008. RESULTS: Three patients had renal failure that required dialysis. One of them received kidney transplantation with no further recurrence of aHUS. Three patients had normal C3, C4, CFH, and FB levels, and in all patients anti-FH autoantibodies were absent. The kidney biopsy of one patient showed in addition to lupus glomerulonephritis histological findings consistent with TMA. A decrease in C3, C4 and CFH levels in this patient was found both before and after the cure. CONCLUSION: Nephrologists should be aware of autoimmune conditions and genetic abnormalities of the complement regulatory genes as possible pathogenic mechanisms in atypical HUS patients.

[Surgical treatment of secondary hyperparathyroidism in patients with chronic renal failure]. / Traitement chirurgical de l'hyperparathyroïdie secondaire chez l'insuffisant rénal chronique.

OBJECTIVE: To identify the indications for subtotal parathyroidectomy (PTX) in secondary hyperparathyroidism (SHPT) and report postoperative, early and late complications of PTX. PATIENTS AND METHODS: We conducted a retrospective study of subjects with chronic renal failure operated in Tunisian hospitals who received subtotal PTX over 10 years from January 1997 to December 2007. We analyzed the clinical, biological and radiological parameters pre- and postoperatively. RESULTS: We included 70 patients with average age of 39.4 years, 55.7% men and 44.3% in dialysis for 7.75 ± 4.8 years before PTX. The initial nephropathy was interstitial in 50% of cases. No cases of diabetic nephropathy have been reported. The clinical signs were bone pain (88.6%), muscle pain (85.6%), pruritus (81.4%). Radiological signs of osteitis fibrosa were observed in the majority of patients mainly resorption of extremities (92.9%), thinning of cortical (85.7%) and osteosclerosis (87.1%). The most common indication of PTX (85.7% of cases) was the persistence of serum PTH of more than 800 pg/ml associated with hypercalcemia and/or hyperphosphatemia refractory to medical treatment. A subtotal PTX (3/4 or 7/8) was performed after ultrasound and scintigraphy in the majority of cases. The histology of the parathyroid glands showed diffuse hyperplasia (51.4%), nodular hyperplasia (45.7%) and adenoma (2.8%). The postoperative evolution was marked by an improvement of the clinical and radiological criteria in 80% of cases. A PTH level of less than 15 pg/ml was rarely observed (10% of cases), and a PTH level of more than 300 pg/ml concerned 13% of patients. We noted a low morbidity and mortality (no cases laryngeal paralysis or cervical hematoma). CONCLUSION: Surgical treatment of SHPT in Tunisia is very effective in our experience. The biological results are comparable to treatment with calcimimetics, not available in Tunisia and whose price is higher. An early treatment of disorders of bone and mineral metabolism should reduce the incidence of SHPT.