[Femoral arteriovenous fistula: a late uncommon complication of central venous catheterization]. / Fistola artero-venosa femorale: rara complicanza tardiva del posizionamento di un catetere venoso centrale per emodialisi.

A 77-year-old woman was admitted due to AV graft thrombosis; given the technical impossibility of performing other native AV fistulas, we chose to insert a tunnelled central venous catheter. Considering the vascular history of the patient, the central venous catheter could not be placed into the internal jugular vein; it was therefore put into the left femoral vein. Following a 3-month-period of the catheter working properly, the patient was hospitalized due to sudden acute pain in the left thigh. In a few days the patient developed an important haematoma with serious anemization in the left lower limb. Ultrasonography showed the presence of a fistula between the left common femoral artery and the femoral vein, leading to the subsequent successful positioning of a stent into the common femoral artery through right trans-femoral access. Angiography examination showed the femoral vein patency along the proximal stretch with respect to the function of the tunnelled venous catheter.

Leptospirosis following a flood in the Veneto area, North-east Italy.

In August 2002, an exceptional flood devastated a suburban area in the surroundings of Vicenza, North-east Italy. A fatal case of haemorrhagic pneumonia, which was presumptively diagnosed as leptospirosis, was observed as a consequence of the inundation. A local seroepidemiological survey was activated thereafter, with the principal aim of evaluating the risk of infection with Leptospirae in the population exposed to the flood. A 6.8% seroconversion rate was found in the population studied; however, the case previously observed remained unique, since an overt outbreak of leptospirosis did not occur.

[Renal function, organic acid transport and protein binding: the three elements defining the response to diuretics in clinical practice: an update]. / Funzione renale, sistema di trasporto degli acidi organici e legame con le proteine.Il triangolo che condiziona la risposta ai diuretici nella pratica clinica: un update essenziale.

Organic anion transporters (OATs), which are expressed in proximal tubule cells, mediate diuretic secretion into tubular fluid. Increased plasma levels of organic anions and urate and metabolic acidosis, i.e. two characteristic features of chronic renal insufficiency, could be factors contributing to diuretic resistance. These limitations demand increasing doses of diuretics up to a maximum level, or the use of a loop diuretic with non-renal metabolism. Diuretic responsiveness in nephrotic syndrome is limited by strong Na+ reabsorption in the distal nephron. Strategies to improve loop diuretic responsiveness include diuretic dosage and the combination of a loop diuretic with a distal acting diuretic. Strategies to limit protein excretion include the use of angiotensin converting enzyme inhibitors or angiotensin receptor blockers and appropriate salt intake limitation.

Mid-dilution: the perfect balance between convection and diffusion.

Although hemodiafiltration (HDF) offers the advantage of increased convective clearance for middle molecules, there is still controversy as to whether reinfusion should occur pre- or post-filter. Mid-dilution hemodiafiltration (MD HDF) is a new HDF technique that uses a special dialyzer, MD190, which allows both pre- and post-reinfusion. While externally the dialyzer looks similar to conventional hemodialyzers, the internal fibers are divided into two bundles by a special annular header that first lets the blood pass through the peripheral bundle in post-dilution, mix with the reinfusion fluid at the opposite end of the dialyzer and then proceed (after pre-dilution) to the dialyzer blood exit. The dialyzer is able to support substantially higher reinfusion rates (10-12 l/h). We have compared the removal characteristics of several small solutes and larger middle-molecular-weight toxins by examining instantaneous clearance at 45 min, the dialysis reduction ratio and total mass removal (by spilling) in a three-center prospective cross-over study. Twenty patients were randomized to a treatment sequence of one-week high-flux bicarbonate hemodialysis (HD) followed by MD HDF, or vice versa. The parameters evaluated included urea, creatinine, beta2-microglobulin, angiogenin, leptin, retinol-binding protein, and the effects on sodium, potassium, bicarbonate and calcium. Blood flow rates ranged between 300-450 ml/min (mean 359 +/- 44 HD, 367 +/- 35 MD HDF). The mean reinfusion for MD HDF was 166 +/-17 ml/min. MD HDF had a significantly better instantaneous clearance for urea (328 +/- 28 vs 277 +/- 40); creatinine (292 +/- 32 vs. 212 +/- 66); phosphate (324 +/- 38 vs. 242 +/- 63); beta2-microglobulin (249 +/- 27 vs. 100 +/- 24); angiogenin (173 +/- 27 vs. 28 +/- 32); and leptin (202 +/- 29 vs. 63 +/- 43). Treatments were well tolerated with no adverse reactions occurring during any of the treatments. The MD HDF filter's unique configuration is designed to deliver high-efficiency HDF with a significant improvement in small and middle molecule removal. MD HDF supports substantially higher ultrafiltration rates, and as such, results in a higher removal of middle-molecular-weight toxins.

[Physical exercise during hemodialysis session: effect on quality of life]. / Contributo dell'esercizio fisico in corso di emodialisi sulla qualità di vita del paziente emodializzato.

There are many studies showing beneficial psychophysical effects of exercise in dialyzed patients. Moreover, it has been suggested that exercise positively correlates with better metabolism, better blood pressure control and with total hemoglobin. In our dialysis unit eight dialyzed patients (average age = 66.7 years), for eight weeks participated in physical training with bike (Reck Moto Med Letto) during dialysis treatment. Controls of glucose metabolism, blood pressure and dialysis efficiency index (Kt/V and URR) at rest and during exercise was performed. All patients responded well to exercise and expressed better muscular performance during and after exercise time. Our study showed in all patients improvement of Kt/V and URR index after physical exercise period, compared to exercise free time (p < 0.005). We suggest that exercise during dialysis treatment is safe and consents either better psychophysical performance or better dialytic efficiency.

[Permanent vascular catheters: Effectiveness and duration of the Ash-Split Cath]. / Cateteri vascolari a permanenza: validità e durata dell'Ash-Split Cath.

In absence of a permanent and useful native arterio-venous fistula, the use of a tunnelled catheter allows dialysis therapy to be carried out. The Ash Split Cath is a recently introduced chronic hemodialysis catheter. An ASC was inserted in nine patients (7.1% of our prevalent dialysis population), for repeated venous thrombosis in seven patients and a poor venous tree in two. The average blood flow rate was 250 +/- 50 mL/minute and the mean venous pressure measured was 140mm Hg +/- 35. Recirculation determined by low flow technique was less than 5% and 4 months after the catheter placement, calculated Kt/V, was 1.2 +/- 0.02. During the follow up we did not document any infection of the exit site or related to the catheter.

[Physiopathology of pre-eclampsia]. / Fisiopatologia della pre-eclampsia.

BACKGROUND: Pre-eclampsia is a pregnancy-specific disorder that presents major health problems for both mothers and babies. It is a major cause of maternal mortality, especially in developing countries, where it may account for 80% of maternal deaths. In this review we have discussed the putative pathogenetic mechanisms of this severe illness. METHODS: Review of the international literature on pre-eclampsia. RESULTS: Pre-eclampsia occurs predominantly in primigravidas and is associated with increased foetal and maternal risk. Generally speaking, one could hypothesise that during pre-eclampsia the oxidative, coagulative and vasomotor balance is altered by increased sensitivity to angiotensin II associated with reduced synthesis of vasodilator prostaglandins, sympathetic nervous system hyperactivity, hyperlipidaemia associated with raised lipoperoxide synthesis and incomplete implant of cytotrophoblast in maternal spiral arteries. General vasoconstriction could then be a consequence with related utero-placental ischaemia and endothelial damage. These features are clinically characterised by arterial hypertension, proteinuria and sodium retention. The predisposition to develop pre-eclampsia seems to be at least partially hereditary and the risk seems to be transmissible through male sons. To explain the susceptibility of some women to develop pre-eclampsia, specific genetic polymorphisms have been associated to increased risk. CONCLUSIONS: Many factors are involved in the pathogenesis of pre-eclampsia. Occasionally these factors seem to act together, sometimes they do not and, consequently, it might be difficult to postulate a common pathogenesis for the disorder. Good obstetrical practice will identify known risk factors but will not enable physicians to determine the risk value for a particular pregnancy. Moreover, we are far from understanding the exact mechanisms involved, let alone acting upon them. The achievement of these objectives constitute a remarkable challenge for research.

[Thoracic lymphadenopathy due to vascular transformation of lymph node sinuses associated with upper limb edema in a chronic hemodialysis patient with congestive heart failure]. / Linfoadenopatia toracica da trasformazione vascolare dei seni linfonodali associata con edema dell'arto superiore in un paziente in emodialisi con insufficienza cardiaca congestizia.

BACKGROUND: Vascular transformation of lymph node sinuses (VTLS) is a rare disorder characterized by transformation of lymph node sinuses into endothelium-lined capillary-like channels. This phenomenon was originally discovered by accident whilst examining regional lymph nodes draining cancer. However, it has been found in association with other conditions associated with lympho venous congestion and distension, such as congestive heart failure (CHF) or even lymphoadenopathy alone. CASE REPORT: We describe the clinical case of a male dialysis patient with CHF (secondary to ischemic-hypertensive cardiac failure) who developed gross edema of the upper left limb on the arteriovenous fistula (AVF) side. Edema appeared within a month after carotid endoarteriectomy following approximately twenty years of chronic hemodialysis. Doppler ultrasound with other investigations showed that subclavian and upper cava veins were patent, but revealed many enlarged lymph nodes in the upper left thorax and in the left axilla. Suspicion of lymphoproliferative disease or metastatic involvement was raised and a lymph node biopsy was performed, revealing VTLS. Bone marrow biopsy and abdominal tomographies showed no mass or a proliferative disorder. Based on a hypothesis of an association between upper limb edema and ipsilateral AVF, the AVF was tied. The upper limb edema decreased dramatically within weeks, whilst RRT was continued by means of a central venous catheter. However, a few months later the patient's condition worsened; he developed relapsing pleural effusions and eventually died. Post-mortem examination revealed severe ischemic-calcific cardiopathy and showed that major thoracic and brachial vessels were patent whilst most thoracic and hilar lymph nodes showed VTLS and fibrosis. CONCLUSIONS: We believe that in our patient CHF was the primary cause of thoracic adenomegaly and that CHF, together with venous hypertension at the left fistula's arm, caused ipsilateral limb edema. Thus, adenomegaly due to VTLS could represent an accompanying feature even in upper limb edema in chronic hemodialysis patients. To our knowledge, this is the first report of such an association. In our patient months were "lost" because we thought that limb edema was secondary to the adenomegaly. It is important that clinicians working in dialysis units are aware that when upper limb edema is present, adenomegaly might just be an accompanying symptom, especially in case of concomitant diagnosis of CHF.

Stomach phytobezoars in two uremic anorexic patients.

Conglomerates of food and mucus or phytobezoars composed of vegetable matter are sometimes found in the stomach in the general population. Reports of phytobezoars in uremic patients are, however, scarce. Here we describe 2 uremic patients in which esophagogastroduodenoscopy was performed due to dyspepsia associated with weight loss and in which stomach phytobezoars were discovered. Theoretically, uremic patients should be at risk for producing bezoars. In fact, these patients frequently present predisposing conditions such as autonomic neuropathy, diabetes mellitus and delayed gastric emptying. Gastric bezoars cause anorexia. Anorexia is a frequent symptom in dialysis patients and is associated with malnutrition. In these patients, malnutrition is strongly associated with mortality and is quite difficult to reverse. Similarly, phytobezoars cause chronic anorexia. We suggest that clinicians working in dialysis units should consider the possibility of a gastric bezoar when evaluating anorexic uremic patients.

Placement, performance and complications of the Ash Split Cath hemodialysis catheter.

A tunneled catheter is the alternative vascular access for those patients in need of hemodialysis who cannot undergo dialysis through an arterio-venous fistula or a vascular graft. This study was undertaken to evaluate the performance of the Ash Split Cath, a 14 French chronic hemodialysis catheter with D-shaped lumens and a Dacron cuff. After tunneling through a transcutaneous portion the catheter enters the venous system, where it splits into two separate limbs. Data regarding catheter positioning, function and adequacy of dialysis were collected from two hemodialysis facilities. Twenty-eight Ash-split catheters were placed in 28 patients, with no complications, and immediate technical success was 100%. Patients were followed up for a total of 7,286 catheter days. No catheter-related infections were observed. Only one catheter failed after 15 days, with a primary catheter patency of 96% for the whole study length. Mean blood flow was 303 +/- 20 ml/min at 1 week after insertion, 306 +/- 17 ml/min at 3 months, 299 +/- 44 ml/min at 6 months, and 308 +/- 16 ml/min at 12 months. With a mean dialysis session duration of 234 +/- 25 minutes, adequate dialysis dose was observed for 96% of catheters, as reflected by a mean urea reduction ratio (URR) of 71% +/- 8 or a mean urea kinetic modeling, or Kt/V, value of 1.51 +/- 0.3 during follow up. In conclusion, compared with previous studies we report the best permanent catheter performance, confirming that the Ash-split catheter is a good alternative for vascular access in hemodialysis patients who are not candidates for surgical A-V fistula or graft placement.

Ash Split Cath in geriatric dialyzed patients.

Vascular access is the essential step in performing hemodialysis in uremic patients. In the absence of a permanent and utilizable native arterio-venous fistula, the use of a tunnelled catheter makes dialysis therapy possible. The Ash Split Cath, a recently introduced chronic hemodialysis catheter, was inserted in five patients (7.1% of our prevalent dialysis population) because of repeated venous thrombosis in three patients and a poor venous tree in two. The mean age of patients was 78 years +/- 7. The average blood flow rate was 250+/-50 ml/minute and the mean venous pressure 140mm Hg +/- 35. Recirculation determined by low flux technique was less than 2%. KT/V calculated 3 months after the catheter placement was 1.2+/-0.02. During the follow-up we did not document any infection of the exit site or related to the catheter. This device is simple to place, gives adequate dialysis treatment and is useful in geriatric dialyzed patients in whom the arterio-venous fistula can no longer be used.

TINU syndrome associated with reduced complement levels.

The TINU syndrome (tubulointerstitial nephritis and uveitis) was first described by Dobrin et al. in 1975. Since then, more than 50 cases have been documented each with diverse immunopathogenetic and genetic characteristics. The aim of this report is to describe a case of TINU associated with reduced complement levels. We profile a 48-year-old white female with persistently reduced C4 complement levels during the acute phase of the pathology and with an unaltered immunologic profile. Renal biopsy evidenced a significant lymphocytic interstitial infiltration. Immunohistochemical studies of the interstitium infiltrates was positive for the presence of the T (CD3) markers (CD4 > CD8). Steroid therapy yielded a complete regression of the symptomatology with normalization of the complement levels. We suggest that it is possible to hypothesize that the various immunologic alterations associated with TINU, including the transient reduction complement levels, may be secondary to multiple inflammatory mechanisms which express themselves throughout the pathology.

Vascular calcification of the venous side of an arterious-venous fistula.

While reports of venous calcifications are scarce, vascular calcifications frequently occur in the arteries of uraemic patients. Venous calcification of an aged arterious-venous (a-v) fistula in a young patient with a long-standing history of hyperparathyroidism was detected on a forearm X-ray. Risk factors for vascular calcifications are still under debate, but calcium-phosphate product appears to be involved in its pathogenesis. We suggest that a-v fistula of patients with hyperparathyroidism history should be monitored as calcifications could be a risk factor for access thrombosis.

Slow maturation of arterio-venous fistula in seven uremic patients: use of Ash Split Cath(R) as temporary, prolonged vascular access.

The temporary vascular access is the essential condition required to perfrom hemodialysis in uremic patients in the absence of a permanent and utilizable vascular access. The cannulation of a central vein with a dual lumen catheter may be useful when a few weeks are required for the maturation of AVF. Longer times for AVF maturation (such as in diabetic patients and in aged patients) impose the use of a tunnelled catheter such as Tesio Catheter or Hickman Catheter which lead to minor complications and more efficient dialysis treatment. The Ash Split Cath(R), a recently introduced chronic hemodialysis catheter, provides dialysis via a transcutaneous portion containing a 14 French cylindrical shaped catheter with D-shaped lumens and a dacron cuff. Due to the slow maturing of AVF, in our Department the Ash Split Cath has been used in 7 uremic patients (3 males and 4 females) who required hemodialysis. The cannulation of the internal jugular vein was performed by an ultrasound assisted technique and the correct catheter position was verified by standard chest X-rays. The average blood flowrates were 250 ml/min, and the mean KT/V calculated in all patients one month after the beginning of the dialytic therapy was 1.09 +/- 0.02. In six patients the catheter was utilized for at least 4 months, in one patient for 8 months. The devices were easily removed when the patient's AVF was functional and usable. We found that the use of the Ash Split Cath as a temporary, prolonged vascular access in uremic patients was op-timal allowing for flexibility in organizing the dialysis treatment schedule and in yielding a good performance in the initial dialysis therapy. Moreover, this device allows, in these patients, a satisfactory dialysis efficiency.

Cannulation of the internal jugular vein: comparison of the classic Seldinger technique and an ultrasound guided method.

Central venous catheterization allows immediate and easy vascular access for hemodialysis. Accidental arterial puncture is the most frequent complication of central vein cannulation and may occur in up to 8% of cases with the classic Seldinger procedure. We compared the Seldinger technique which implies manual localization of the vascular access, and an ultrasound guided technique, to assess whether the latter is an improvement on the Seldinger procedure.

Assessment of adequacy in peritoneal dialysis.

Adequacy of peritoneal dialysis has been less well studied than that of hemodialysis. Fractional urea removal, total creatinine removal, and various indices have been proposed to reflect or predict patient morbidity and mortality. No prospective study has been published in this regard. To evaluate this area further, in addition to reviewing selected literature, 45 continuous ambulatory peritoneal dialysis (CAPD) patients were recruited in two dialysis centers for a prospective study on treatment adequacy. Patients were well rehabilitated and had no peritonitis or hospitalization in the 6 months before the study. Urea and creatinine kinetics were analyzed, as were dietary intake and fluid balance. The weekly Kt/V, calculated to include peritoneal and residual renal clearance (KprT/V), averaged 1.77 with a Kt/V hemodialysis equivalent of 0.59. Patients with residual renal function (58% of the studied population) had an average residual renal clearance of 3.42 mL/min, and had lower steady-state concentrations of urea nitrogen and creatinine in the plasma than patients with no residual renal function. As a consequence, a lower percent excretion of urea and creatinine in the peritoneal fluid was observed in the former patients compared with the latter, where the peritoneal route was the only one for solute excretion. The concentration profiles in blood appear to be the critical factor in achieving the final target of the treatment, ie, the excretion of the overall amount of waste products derived from protein and other metabolic pathways. The constant blood levels in CAPD explain why such a low Kt/V can be adequate whereas, in hemodialysis, a higher Kt/V is required.(ABSTRACT TRUNCATED AT 250 WORDS)