A case series of falciparum malaria-induced acute renal failure

Falciparum malaria is a disease of tropical climates which affects 270 million people annually and has an overall mortality of 1%. While the incidence of acute renal failure in malaria is less than 1%, mortality is reported to be as high as 45% in those with renal failure. We report the clinical course and outcome in 5 patients with falciparum malaria-induced acute renal failure treated at the Singapore General Hospital between June and July 1997. All 5 males, with mean age of 35.2 +/- 13.1 years, were admitted with history of fever and reported travel to a known malarious zone. Mean laboratory parameters upon admission included serum creatinine 725 +/- 515 mumol/L and serum urea 47 +/- 31 mmol/L. Three patients with hypotension on admission were started on haemodiafiltration, of whom 2 were subsequently converted to haemodialysis as their haemodynamics improved. Two remaining patients were started on intermittent bicarbonate haemodialysis. The overall mortality in our series was 20%, with 1 patient having died of complications of adult respiratory distress syndrome, disseminated intravascular coagulation and multiorgan failure. The remaining 4 survived and recovered their renal function. The single patient mortality occurred in the patient with admission serum creatinine of 1632 mumol/L, a value significantly higher than that of the 4 patients who survived (mean serum creatinine, 499 +/- 106 mumol/L, P < 0.002). These results suggest that falciparum malaria associated with acute renal failure is associated with a high morbidity, but early presentation and intervention with appropriate antimalarial and renal replacement therapy is associated with improved survival and recovery of renal function.

Preliminary results of heart-beating and non-heart-beating donor kidney transplants--the Singapore experience

Renal transplantation is the ideal renal replacement therapy for treatment of end stage kidney failure but its limitation is the constant shortage of cadaveric donors. While the traditional source of cadaveric kidneys is procurement from heart-beating donors, organ procurement from non-heart-beating donors (NHBD) would help in coping with the rising demand for organs. However various important legal, logistic and technical constraints have limited the implementation of such a procurement programme. Nevertheless, prolonged warm ischaemic times in procuring kidneys from NHB donors may affect the viability of these organs and adversely affect overall outcome after transplant. Fifty-three consecutive patients who underwent renal allotransplantation (Tx) between January and December 1994 at the Singapore General Hospital were retrospectively reviewed. Outcomes after renal transplantation among 25 heart-beating donor (HBD) and 28 NHBD were compared. Despite significant differences in donor age (23.7 +/- 11.0 and 34.1 +/- 7.9, P = 0.001), first warm (0 and 22.2 +/- 9.0 minutes) and cold ischaemic times (12.8 +/- 6.7 and 5.2 +/- 5.0 hours, P = 0.001) between the HBD and NHBD groups, the two-year patient and graft survivals were very similar in both groups (100% versus 98% and 98% versus 96%). The incidence of delayed graft function (DF) was also comparable between the HBD (41%) and the NHBD (50%) Tx. These results suggest that NHBD is a viable source for kidney transplants and comparable patient and graft survivals can be achieved if the first warm and cold ischaemic times are kept to the minimum.

Renal transplantation in cyclosporine-treated recipients at the Singapore General Hospital

1. The 5-year patient and graft survival rates for live-donor renal transplants undergoing transplantation with CsA-based immunosuppression at the Singapore General Hospital from 1985-1999 were 97.0% and 91.6%, respectively. The 5-year patient and graft survival rates for cadaveric renal transplant recipients from the same institution were significantly lower at 91.6% and 79.4%, respectively. Long-term graft survival as described by half-lives (T1/2) were 28.6 years and 20.4 years for live-donor and cadaveric grafts, respectively. 2. Tissue matching had no impact on graft or patient survivals in either live-donor or cadaveric renal transplants. However, sensitisation was associated with significantly worse graft survival in cadaveric transplant recipients. 3. Primary cadaveric transplant recipients enjoyed significantly better graft survival rates than retransplanted recipients (5-year survival rates of 80.1% and 65.0%, respectively; p = 0.032). 4. Among cadaveric renal transplant recipients, a single acute rejection episode was associated with worse long-term graft survival (T1/2 of 14.6 years and 37.0 years for those with and without rejection, respectively, p = 0.001). Likewise, delayed graft function was associated with worse overall graft survival (5-year graft survival rates of 70.7% vs. 86.8% in patients with and without DGF, respectively, p < 0.001). 5. Among cadaveric transplant recipients with a functioning kidney at 5 years after transplantation, 61.4% had normal renal function with serum creatinine levels < 141 mumol/L while 33.9% had mild renal dysfunction with SCr of 141-250 mumol/L. 6. The high graft and patient survival rates in this Asian population as reported from this single centre study may be attributed to selection of younger patients without overt ischaemic heart disease for transplantation and to good patient compliance to CsA therapy. Thus, recipient selection and ensuring patient compliance to treatment are key strategies in optimizing the use of a scarce resource such as organ transplants.

Partial sequence analysis of the hepatitis C viral genome in Singapore patients

The distribution of hepatitis C viral (HCV) genotypes in Singapore has not been previously determined. We studied the sera of 40 Singapore patients which were PCR-positive for HCV. The HCV genotypes were determined by direct sequencing of amplified sequences of the 5' non-coding region, after reverse transcription. Of the 40 samples, 35/40 (87.5%) were of HCV type 1, 2/40 (5.0%) were of type 2 and 3/40 (7.5%) were of type 3. The most common HCV genotype in this study was the type 1 genotype. Our results confirm the wide geographical distribution of HCV genotypes.

The impact of percutaneous renal biopsies on clinical management

Percutaneous renal biopsy (PRB) is now standard practice in clinical nephrology. One hundred consecutive non-transplant PRBs performed on adult patients at the Department of Renal Medicine, Singapore General Hospital, between January and August 1990, were analysed to examine the impact and complications of PRBs in a single institution. The study population consisted of 37 male and 63 female patients with a mean age of 32 +/- 11.9 years. The most frequent indications for PRB were systemic lupus erythematosus with renal involvement (41 patients), haematuria and proteinuria (27 patients) and the nephrotic syndrome (26 patients). Histological diagnoses included lupus nephritis in 45 patients, IgA nephritis in 19 patients, minimal change/focal global sclerosis in 14, non-IgA mesangioproliferative glomerulonephritis in seven and other histologies in the remainder. Eighty-two of our patients received renal-specific therapy, including 72 who received prednisolone or other immunosuppression, and 11 who received persantin and warfarin, in contrast to only 18 patients who received non-specific therapy including diuretics, antihypertensive drugs or dialysis. PRB led to change in therapy in 54% of all our patients, including 42 who had immunosuppressive drugs added to their therapeutic regimen and 11 who were commenced on persantin and/or warfarin. Complications of the procedure were minimal with flank pain in 6% and gross haematuria in 4%. As the inherent risks of inappropriate immunosuppression are well established, these results suggest that PRBs have a major impact on clinical management.

Cytomegalovirus infection in renal transplant patients with hepatitis B--case report

Cytomegalovirus (CMV) infection in Hepatitis B carrier renal transplant patients who are immunosuppressed can be easily overlooked especially in those presenting with jaundice and liver failure. Recognising hepatitis due to CMV in renal transplant patients who are also hepatitis B carriers is important therapeutically as measures for the treatment and prevention of CMV infection are already available. This is especially so as Hepatitis B has a moderately high prevalence in this part of the world. We describe our clinical experience of cytomegalovirus infection in two renal transplant patients who are also asymptomatic hepatitis B carriers.

Results of total hip replacement in renal transplant recipients

A vascular necrosis of the femoral head associated with steroid immunosuppression is a cause of significant morbidity in renal transplant recipients. We review the results of 30 total hip replacements in 20 renal transplant recipients with a mean follow-up of 6.3 years. The mean age at the time of surgery was 35 years. The average Hospital for Special Surgery Hip Score was 17 points before operation and 32 points after operation. Fourteen hips were rated excellent and 12 hips rated good. There were four failures--one hip was revised for symptomatic loosening and three prosthesis were removed for infection. Twenty-seven of the hip replacements were subjectively rated as satisfactory by the patient. There was no significant difference in post-operative hip scores between cemented and uncemented prostheses. Total hip replacement in renal transplant recipients in this study has shown good long term result with a revision rate of about 3%. Late infection was a major problem with an incidence of 13%. Prophylactic antibiotics must be used whenever there is a risk of haematogenous seeding from transient bacteremia in these immunosuppressed patients. Use of uncemented prosthesis may make future revision arthroplasty easier.

The impact of HLA match transfusions and presensitization on renal transplantation in the cyclosporine era

The successful engraftment of a renal transplant is dependent on multiple factors, immunological factors being of major importance. Specifically, histocompatibility, lymphocytotoxic antibodies and pretransplant blood transfusions have been shown to play a major role in determining graft outcome in renal transplant recipients receiving Azathioprine-Prednisolone immunosuppression. The impact of the immunosuppressive drug, Cyclosporine on graft outcome in relation to established risk factors were examined among 116 cadaveric and 34 living related renal allograft recipients from our center. Histoincompatibility and pretransplant blood transfusions did not significantly affect graft survival among cadaveric transplant recipients. Similarly, graft survival was not significantly different between two haplotype-matched and less well-matched living-related graft recipients (75% versus 96.5% respectively). On the other hand, lymphocytotoxic antibodies remained a major risk factor for immunologically mediated graft loss among cadaveric graft recipients (48.0% versus 92.2% four year graft survival among those with and without antibodies respectively). These results suggest that Cyclosporine has abrogated some immunological risk factors in renal transplantation.

The immunosuppressive antagonism of low doses of FK506 and cyclosporine

Clinical immunosuppression with potentially toxic agents may be optimized by combining drugs that act synergistically at low doses. The studies presented herein attempted to apply this strategy to the macrolide FK506 and the endecapeptide cyclosporine, which similarly inhibit T cell responses but display distinctive arrays of toxic side effects. The interaction between these agents was subjected to rigorous pharmacologic analysis using the median effect and combination index equations to determine synergistic, antagonistic, or additive drug interactions. FK506 and CsA showed pharmacologic antagonism in inhibiting in vitro proliferation upon phytohemagglutinin, anti-CD3 antibody, and mixed lymphocyte reaction (MLR) stimulation, and interleukin 2 generation by activated normal human peripheral blood lymphocytes. The antagonistic relationship was confirmed in vivo using low doses of FK506 in combination with CsA to treat Wistar-Furth recipients of heterotopic Buffalo rat cardiac allografts, a major plus minor histocompatibility barrier. This antagonistic relation suggests that FK506/CsA combination therapy does not permit dose reduction of the individual drugs to mitigate toxic complications.