Rifabutin-Induced SIADH and Leucopenia in a Renal Transplant Recipient with Genitourinary Tract Tuberculosis: A Case Report and Review of the Literature.

Tuberculosis (TB) infection of the genitourinary tract (GU TB) is rare in renal transplant recipients, with only a few published case series. GU TB is difficult to diagnose with or without immunosuppression but must always be suspected in any patient with unexplained sterile pyuria. As GU TB is associated with graft rejection, prompt diagnosis and treatment are vital. Treatment is challenging, as rifampicin, the most effective drug used to treat tuberculosis, is a significant inducer of cytochrome P-450 3A metabolism, with the potential to cause significant reductions in the serum levels of calcineurin inhibitors. For this reason, rifabutin, a weaker cytochrome P-450 3A inducer, with similar efficacy against TB, is sometimes used as an alternative to rifampicin in transplant recipients. We present a renal transplant patient diagnosed with GU TB, treated with a regime containing rifabutin, who subsequently developed profound hyponatremia and leucopenia. Serum and urine biochemistry was consistent with a diagnosis of the syndrome of inappropriate antidiuretic hormone secretion (SIADH). Both SIADH and leucopenia resolved with rifabutin cessation. This is the first report of biochemically proven, idiosyncratic SIADH and leucopenia associated with the use of rifabutin in the treatment of GU TB in a renal transplant recipient.

Deceased donor kidney transplantation in New Zealand: use and audit of a survival prediction tool.

AIMS: New Zealand follows the guideline that only patients with projected five-year survival of 80% are listed for deceased donor kidney transplantation. An algorithm derived from US data estimates survival after transplantation, however, this may not be as applicable to the New Zealand population. We review use of the US derived algorithm in New Zealand. We assessed accuracy of scores calculated by referring units and audited whether the system is applied in New Zealand. METHODS: Data on 422 patients assessed for transplantation was entered into the algorithm to calculate a projected survival score. Scores were generated by an independent investigator and compared with those calculated by local units. Scores and demographics of listed and not-listed patients were also compared. RESULTS: Three hundred and twenty-five of 420 (77%) patients assessed were accepted onto the New Zealand transplant list. Mean estimated five-year survival in listed patients was 89.4% compared to 79.8% in those not accepted (p<0.0001). Listed patients were younger and less likely to have coronary artery disease (CAD). There was no significant difference in scores calculated by the independent assessor and referring centres (p=0.185). CONCLUSION: The algorithm is universally and accurately used. Future studies are required to determine the validity of the system in New Zealand patients.

Communicating projected survival with treatments for chronic kidney disease: patient comprehension and perspectives on visual aids.

BACKGROUND: Mortality in end stage renal disease (ESRD) is higher than many malignancies. There is no data about the optimal way to present information about projected survival to patients with ESRD. In other areas, graphs have been shown to be more easily understood than narrative. We examined patient comprehension and perspectives on graphs in communicating projected survival in chronic kidney disease (CKD). METHODS: One hundred seventy-seven patients with CKD were shown 4 different graphs presenting post transplantation survival data. Patients were asked to interpret a Kaplan Meier curve, pie chart, histogram and pictograph and answer a multi-choice question to determine understanding. RESULTS: We measured interpretation, usefulness and preference for the graphs. Most patients correctly interpreted the graphs. There was asignificant difference in the percentage of correct answers when comparing different graph types (p = 0.0439). The pictograph was correctly interpreted by 81% of participants, the histogram by 79%, pie chart by 77% and Kaplan Meier by 69%. Correct interpretation of the histogram was associated with educational level (p = 0.008) and inversely associated with age > 65 (p = 0.008). Of those who interpreted all four graphs correctly, there was an association with employment (p = 0.001) and New Zealand European ethnicity (p = 0.002). 87% of patients found the graphs useful. The pie chart was the most preferred graph (p 0.002). The readability of the graphs may have been improved with an alternative colour choice, especially in the setting of visual impairment. CONCLUSION: Visual aids, can be beneficial adjuncts to discussing survival in CKD.

Rare genetic variants in Shiga toxin-associated haemolytic uraemic syndrome: genetic analysis prior to transplantation is essential.

We present a case of haemolytic uraemic syndrome (HUS) in a 16-year-old female with serological evidence of acute Escherichia coli O157:H7 infection. She progressed to established renal failure and received a deceased donor kidney transplant. Shiga toxin-associated HUS (STEC-HUS) does not recur following renal transplantation, but unexpectedly this patient did experience rapid and severe HUS recurrence. She responded to treatment with the terminal complement inhibitor eculizumab and subsequent genetic analysis revealed a rare variant in a complement gene. This highlights the importance of genetic analysis in patients with STEC-HUS prior to renal transplantation so that management can be individualized.

Successful treatment of hypercalcaemia associated with a CYP24A1 mutation with fluconazole.

Mutations in CYP24A1, encoding the vitamin D 24-hydroxlase enzyme, are known to cause a range of clinical phenotypes and presentations including idiopathic infantile hypercalcaemia and adult-onset nephrocalcinosis and nephrolithiasis. In the context of raised or borderline high serum calcium levels, suppressed PTH and persistently elevated 1,25 dihydroxy vitamin D levels, this rare condition should be considered. We present a case where this biochemical pattern was seen and mutations in CYP24A1 were confirmed. We were able to successfully control serum calcium levels and reduce urinary calcium excretion by treatment with low-dose fluconazole, which inhibits vitamin D-synthesizing enzymes (including 25-hydroxylases and 1-α-hydroxylase) thereby reducing levels of 1,25-dihydroxy vitamin D.