Simple pressure measurement is not reliable in detection of access stenosis in native AV fistulas.

Dynamic arterial and venous pressures (PA, PV) are used as the simplest tools to assess vascular access quality (VAQ). An increased PV over three consecutive dialyses is believed to indicate a stenosis, a rule devised for synthetic grafts (AVG) but not adequately validated for AV fistulas (AVF). In this study dynamic PV and static intra-access pressure (calculated by means of the simplified formula PIA=(PA+PV)/2) changes were evaluated in 46 accesses in which balloon angioplasty had to eventually be performed. The whole group consisted of 30 forearm AVF, 5 upper arm AVF and 11 AVG. Pressures were compared in each patient at a time of satisfactory access flow (QVA) and immediately before the angioplasty and pressure difference over that period (deltaPV, deltaPIA) evaluated. Despite a significant drop in QVA over the follow-up interval in both AVF and AVG, the mean deltaPV and deltaPIA in AVF were only several mm Hg and the chosen threshold limit of 20 mmHg was exceeded in approximately 10% of patients only. The results in the AVG group were, however, very different: The mean deltaPV and deltaPIA were close to 20 mmHg and almost 60% of patients in the AVG group exceeded this limit. Evaluation of PIA did not improve stenosis detection in either group. It is concluded that PV and/or PIA monitoring may be useful to detect a stenosis in AVG but not in AVF.

[Tuberculosis in patients with chronic kidney failure]. / Tuberkulóza u pacientu s chronickým selháním ledvin.

BACKGROUND: In a retrospective study we analysed the incidence of tuberculosis (tb) in end-stage renal disease patients undergoing dialysis treatment at the Department of Medicine Strahov, General University Hospital, 1st Medical Faculty, Charles University, Prague. Study included patients who died and were autopsied from 1991 till 2000. METHODS AND RESULTS: Active tb was found in 11 cases (4 men and 7 women, age 56 to 84 years) from the total of 275 patients, i.e. in 4%. The results confirmed the increased risk of tb in our group as compared to general population. Tuberculosis was diagnosed of in 2 patients before they died and in 3 patients there was a suspicion of tb before the death. In 6 cases tb was found during autopsy. Unlike the non-dialysed population, where pulmonary tb has the highest incidence (in Czech republic 75%), in the studied group extrapulmonary forms of tb were predominant (9 patients, i.e. 81.8% had some form of extrapulmonary tb). Miliary tb was found in 8 cases (72.7%). Because the symptoms of tb are unspecific and they are not pathognomonic, they were masked by other, already known diseases in patients with multiple co-morbidities. The low number of cases of tb diagnosed before death represents a serious problem. Obviously, it is difficult to prove tb unambiguously, even when such possibility is taken into account. CONCLUSIONS: In differential diagnosis, we always have to bear in mind the possibility of the patient having tb. In examination algorithm we have to concentrate on both pulmonary and extra-pulmonary forms of tb.

[Renal bone disease]. / Renální kostní choroba.

Renal bone disease is a serious complication associated with chronic renal failure. The pathogenetic mechanisms are very complicated. The disorder develops as a result of hypophosphataemia, hypocalcaemia and calcitrol deficiency already during the period when renal functions decline below 50%. Formerly the form with an excessive bone turnover predominated, nowadays we encounter ever more frequently so-called a dynamic bone disease. A serious manifestation are extraosseous calcifications. In treatment phosphate binding substances in the gastrointestinal tract are involved (along with other provisions, correcting hypophosphataemia), supplementation of calcium in case of hypocalcaemia correction of metabolic acidosis and administration of the active vitamin D metabolite (continuously as supplementation in deficient endogenous production, in a pulsatile pattern with the aim to suppress the activity of parathyroid bodies). In case of "resistant" hyperparathyroidism surgery is indicated (parathyroidectomy). Treatment of the dynamic form is not known, prevention of suppression of excessive parathyroid activity is important. New trends in the treatment of renal bone disease are non-calcium phosphate binding substances in the gastrointestinal tract, vitamin D analogues (with a lower hypercalcaemic potential) and calcium mimetics.

[The calciphylaxis syndrome as a complication of chronic kidney failure. 6 case reports and literature review]. / Syndrom kalcifylaxe jako komplikace chronického selhání ledvin. Popis sesti kasuistik a literární prehled.

Calciphylaxis is a rate complication of unknown pathogenesis in patients with end stage renal disease. It is characterized by calcification of tunica media of small arteries associated with intimal fibrosis and thrombus formation which leads to the development of skin and subcutaneous tissue necrosis. Superinfection of skin lesions is a common consequence of this syndrome which may lead to the sepsis. The prognosis of this condition in serious. We performed a retrospective study of 6 subjects (4 men and 2 women) in the age of 35 to 59 years. We followed the parameters of calcium-phosphate metabolism, presence of calciphylaxis risk factors and the effect of parathyreoidectomy. Five patients were on hemodialysis, one had a kidney transplant. Skin and subcutaneous tissue necrosis were present in all subjects. The serum levels of parathormone were either high, normal or low, levels of calcium were normal or slightly elevated and phosphate levels were high or normal. Calcium was substituted before calciphylaxis development in 5 patients, calcitriole in 3 of therm. Five patients underwent parathyroidectomy. Three patients died (all of sepsis), one patient had the lower into amputation for infected lesions and the remaining two achieved regression. Our findings do support the hypothesis that calcium and calcitriole administration participates in development of calciphylaxis. Fatal prognosis of the once infections skin lesions was also proved.