Ten-year prognosis of Puumala hantavirus-induced acute interstitial nephritis.

Nephropathia epidemica (NE) is a hemorrhagic fever with renal syndrome caused by Puumala hantavirus. Its long-term prognosis is considered favorable. There are, however, some reports about subsequent hypertension, glomerular hyperfiltration, and proteinuria after previous hantavirus infection. Therefore, we studied 36 patients 5 and 10 years after acute NE, with 29 seronegative controls. Office blood pressure, ambulatory 24-h blood pressure (ABP), glomerular filtration rate (GFR), and proteinuria were examined. Hypertensive subjects were defined as those patients having increased ambulatory or office blood pressure, or receiving antihypertensive therapy. Office blood pressure was used to define hypertension only if ABP was not determined. At 5 years, the prevalence of hypertension was higher among NE patients than in controls (50 vs 21%, P=0.020). At 10 years, the difference between the groups was no more significant (39 vs 17%, P=0.098). Five years after NE, patients showed higher GFR (121+/-19 vs 109+/-16 ml/min/1.73 m(2), P=0.012) and urinary protein excretion (0.19 g/day, range 0.12-0.38 vs 0.14 g/day, range 0.09-0.24, P=<0.001) than controls. At 10 years, there were no more differences in GFR or protein excretion between the groups (GFR: 113+/-20 vs 108+/-17 ml/min/1.73 m(2), P=0.370; proteinuria: 0.14 g/day, range 0.07-0.24 vs 0.13 g/day, range 0.06-0.31, P=0.610). In conclusion, the 10-year prognosis of NE is favorable, as glomerular hyperfiltration and slight proteinuria detected at 5 years disappeared during the longer follow-up. However, the possibility exists that NE may predispose some patients to the development of hypertension.

Kidney ultrasound and Doppler ultrasound findings during and after acute urinary retention.

OBJECTIVE: To evaluate changes in kidney ultrasound and Doppler ultrasound images during and subsequent to acute urinary retention (AUR). METHODS: Twenty-five men with a mean age of 69 years suffering AUR for a mean of 31 h were studied by measuring serum creatinine, creatinine clearance and renal ultrasound. Renal Doppler ultrasound was applied in 19 of these cases and all patients were followed for 6 months after acute retention was relieved. RESULTS: During AUR hydronephrosis was noted in three patients; this disappeared during follow-up. During the acute period, after 1 month and after 6 months the average resistive indexes (RI) were 0.71, 0.70 and 0.69, respectively. The changes were not statistically significant. During follow-up, the proportion of patients with normal RI increased from 42 to 64%. Median serum creatinine was normal during retention and follow-up. Median creatinine clearance was reduced during retention and became normal during follow-up (P < 0.05). No correlation was found between RI and serum creatinine at any time-point, nor was any correlation noted between RI and creatinine clearance during retention or at the 1-month follow-up; at 6 months, however, there was a significant inverse correlation between them (P = 0.01). CONCLUSION: AUR caused elevation of RI, which may be interpreted as diminished renal blood flow. Although in the majority of patients it recovered after treatment, elevated RI was still found in one third of the patients, possibly due to previous chronic bladder outlet obstruction. Our findings stress the importance of both fast release of AUR and effective treatment of its cause.

Long-term renal dysfunction in patients with acute urinary retention.

OBJECTIVE: Acute urinary retention (AUR) causes bilateral renal obstruction, which has been found to affect kidney function. This study evaluated both glomerular and tubular renal function in the long term after the resolution of AUR. MATERIAL AND METHODS: Renal function in 15 patients affected by AUR and found still to evince renal dysfunction 6 months afterwards was re-evaluated approximately 18 months after the episode. The bladder outlet obstruction was treated and all patients voided normally at 6 month control. RESULTS: The percentage of patients suffering from lowered creatinine clearance and elevated alpha1-microglobulin excretion increased during follow-up from AUR up to 6 and 18 months (46% to 57% to 79% and 42% to 71% to 100%, respectively). In addition, daily protein excretion was abnormally high in 69% of patients at the 18 month follow-up. In most cases the abnormalities found in renal function were mild. CONCLUSION: Patients evincing renal dysfunction 6 months after AUR showed permanent impairment in tubular function, whereas glomerular permeability had partially recovered. Although this may be explained in part by chronic obstruction prior to AUR and although the impairment was mild in most cases, these findings stress the importance of urgent treatment of AUR to avoid the development of renal failure.

Characteristics of protein excretion in patients with acute urinary retention.

OBJECTIVE: To evaluate changes in protein leakage in the glomerular filtration barrier, and in the ability of the tubule to reabsorb proteins during and after acute urinary retention (AUR). PATIENTS AND METHODS: Glomerular and tubular function was investigated in 24 men during AUR (mean age 68 years, mean retention time 31 h and mean retention volume 1140 mL) who were then followed for 6 months by measuring the urinary excretion of glomerular and tubular proteins, and the glomerular filtration rate (GFR). Retention was relieved by inserting a suprapubic catheter and the cause of retention treated one month later. No patient had a previous renal disease or diabetes. RESULTS: During AUR, and after 1 and 6 months, albuminuria was detected in 100%, 92% and 54% of patients, and increased excretion of alpha1-microglobulin in 52%, 36% and 58%, of IgG in 79%, 58% and 40%, and of IgG4 in 67%, 42% and 20%, respectively. The mean GFR was normal during retention and during the follow-up. CONCLUSION: AUR causes disturbances in both the glomerular filtration and tubular reabsorption of proteins. Albuminuria and increased excretion of IgG, IgG4 and alpha1-microglobulin occurred in most patients during AUR. After relieving retention, the albuminuria and elevated alpha1-microglobulin excretion persisted, indicating slight glomerular dysfunction and a permanent defect in the proximal tubule to reabsorb proteins. This could be caused partly by previous chronic obstruction. AUR should be relieved immediately and the basic cause treated effectively to prevent further deterioration of renal function.

Adequate seroresponse to influenza vaccination in dialysis patients.

BACKGROUND: Hemodialysis (HD) patients are immunocompromised, and they have been shown to react suboptimally to recommended vaccinations. Advances in dialysis therapy and other supportive measures may theoretically result in better immune system functions. Clinical evidence supporting this theory has, however, not been presented. With influenza vaccination response, we tried to address this question. METHODS: 42 HD and 15 continuous ambulatory peritoneal dialysis (CAPD) patients were vaccinated with a trivalent influenza vaccine, and the seroresponses at 5 weeks were measured. The results were compared with those of similarly vaccinated 20 nephrology outpatient clinic patients with varying degrees of renal insufficiency and those of 31 cardiac patients with normal renal function. RESULTS: The dialysis patients had higher prevaccination titers of hemagglutination-inhibiting (HI) antibodies to all three vaccine virus antigens than the other groups due to more frequent previous vaccinations. The dialysis patients exhibited lower antibody increases, but an almost comparable proportion of them reached a protective antibody level (HI titers > or =40) 5 weeks after vaccination [A/H3N2: 61% (cardiac patients), 35% (nephrology outpatient clinic patients), 67% (CAPD), and 36% (HD); A/H1N1: 71, 70, 80 and 60; B: 97, 90, 80, and 76%, respectively]. Among the HD group, all patients receiving parenteral calcitriol except 1 (83%), but only 50% of the other HD patients produced protective antibody titers at least to two out of three vaccine virus antigens. No other patient- or HD treatment-associated parameter was significantly related to the vaccination-induced antibody response. CONCLUSIONS: We conclude that influenza vaccination of dialysis patients according to current recommendations may be effective. Additionally, our results suggest that parenteral calcitriol treatment may augment the immune response of HD patients even in a clinically relevant way, an effect so far shown only in in vitro studies.

Does uremia interfere with HbA1c results in the FPLC method with Mono S cation exchanger?

To study the effect of uremia on hemoglobin A1c determination by the Mono S FPLC method, samples from uremic patients, with and without diabetes, and controls, were analysed with a modified chromatography with enhanced resolution. Besides specific HbA1c, four minor peaks could be seen, included in routine HbA1c values. Two of these differed in concentration in the patient groups studied: a shoulder-like peak close to the specific HbA1c (S fraction) and a slightly less cationic minor peak (M fraction). Both S and M peaks were higher in uremic than in nonuremic subjects, but the M peak was associated more with diabetes. In the nondiabetic group, the mean routine HbA1c value was 0.8% units higher in uremic than nonuremic individuals. The specific HbA1c was nondependent on uremia. Thus, in uremic patients, there seems to be falsely elevated HbA1c values, mainly because of small interfering hemoglobin fractions, not specific HbA1c.

Pharmacokinetics of clodronate in peritoneal dialysis patients.

OBJECTIVE: To study the pharmacokinetics of clodronate in patients on continuous ambulatory peritoneal dialysis (CAPD). DESIGN: A single intravenous dose pharmacokinetic study. SETTING: University hospital. PATIENTS: Ten CAPD patients (3 female, 7 male, age 39-79 year, median 55). METHODS: Clodronate disodium in serum, urine, and dialysate was collected for 24 hours and analyzed by capillary gas chromatography with mass-selective detection. RESULTS: Only 7% of the infused dose of clodronate was eliminated through peritoneal dialysis during 24 hours. Clearance via CAPD (CL[CAPD]) was 2.4 +/- 0.6 mL/min, which was less than 10% of the total serum clearance (CL(tot), 26.0 +/- 19.3 mL/min). Even the kidneys were a more important route of elimination than CAPD in those patients with residual diuresis of more than 500 mL/24 hr. However, in all patients most of the clodronate serum clearance (77% +/- 13%) took place via routes other than peritoneal dialysis or kidneys, that is, via nonrenal-non-CAPD clearance (CL[NRD]). CL(NRD) most likely represents the part of the drug deposited in the skeleton. There was a positive correlation between CL(NRD) and the plasma intact parathyroid hormone concentration. CONCLUSIONS: CAPD removed clodronate poorly from the circulation. Most clearance took place via routes other than CAPD or kidneys. This CL(NRD) most likely represents the skeletal deposition of the drug, and this is related to the severity of hyperparathyroidism. When treating CAPD patients with hyperparathyroid bone disease, the administration of clodronate should be adjusted as in those subjects with severe renal failure.