[Hyperkalemia: the new killer?]

Hyperkalemia is now commonly observed due to several associated factors such as old age, diabetes, congestive heart failure, renal insufficiency and drugs such as spironolactone used to improve cardiac function. Moreover, the easily prescribed new antiinflammatory drugs COX2 selective inhibitors in these patients lead to a very acute risk for vital hyperkalemia development. This review insists on the prevention of such potentially reversible disorder.

[News about phosphorus metabolism]

Phosphorus is mainly present in the serum as phosphate which is the principal intracellular anion, essential for the organism, in particular through its role in the production of ATP. In plasma, only inorganic phosphorus (Pi) is measured. In this article, we will review new information about the regulation of Pi at the intestinal, osseous and mainly renal levels. The various cotransporters sodium-phosphorus (Na-Pi) will also be examined and the molecular regulation mechanisms approached. Finally, illustration of Pi physiology will be given through various clinical examples.

Primary amyloidosis (AL) as a cause of nephrotic syndrome

AL amyloidosis is a rare systemic disease resulting from tissue accumulation of amyloid fibrils derived from monoclonal immunoglobulin light chains. It can disrupt the tissue architecture and consequently cause organ dysfunction. The prognosis is poor with a median survival of 13 months in untreated patients. By illustrating the case of a patient whose AL amyloidosis was detected after presenting a nephrotic syndrome, the characteristics of the disease are reviewed as well as diagnostic criteria and current available therapeutics.

[Blood pressure variability]

Blood pressure variability is a physiological phenomenon influenced by many internal and external factors. This variability could be also influenced by pathological conditions such as arterial hypertension. Two forms must be mainly distinguished: the blood pressure variability at long but also short-term. The latter could only be studied by continuous recordings. From the initial invasive intraarterial approach, it can nowadays be explored by a non invasive system of beat to beat recordings using the infrared photo plethysmography (the FINAPRES system). In this paper, some important questions will be treated such as the interest of measuring blood pressure variability, its cardiovascular prognosis and how therapeutic tools can be applied when it is increased?

Effect of haemodialysis on acoustic shear wave propagation in the skin

BACKGROUND

Diverse skin alterations may develop in patients under chronic haemodialysis. Among them, signs of premature photo-ageing have been described.

AIM

To assess alterations in the physical properties of skin consistent with ageing effects and with cutaneous fluid exchanges during haemodialysis sessions.

METHODS

In the first part of the study, 45 haemodialysed patients were compared to 45 age-, sex- and body-mass-index-matched healthy subjects. In the second part of the study, skin of 30 haemodialysed patients was assessed immediately before and after a haemodialysis session. The speed of ultrasound shear wave propagation was measured in each subject. Series of 16 multidirectional resonance running time measurements (RRTM) were performed on the forehead and/or the volar forearm. They were averaged for each subject. The corresponding intra-individual coefficients of variation were calculated as an estimate of the skin mechanical anisotropy.

RESULTS

In both haemodialysed patients and their matched controls, RRTM values were significantly higher on the forearms than on the forehead. By contrast, no significant difference was found in RRTM values that could be ascribed to chronic haemodialysis. However, RRTM values were significantly increased as an immediate and probably transient effect of haemodialysis sessions. In healthy subjects, ageing was associated with increased RRTM values.

CONCLUSION

Chronic haemodialysis does not appear to influence significantly the functional expression of the dermal ageing process. Subtle fluid movements occurring in the skin during haemodialysis sessions can be assessed by measuring non-invasively the speed of ultrasound shear wave propagation in the skin.

[How to explore... insipidus polyuropolydipsia syndrome]

The finding of a polyuropolydispsic syndrome should prompt a complete biological investigation of its etiology. If polyuria can be a minor sign as in psychiatric disorder, it can also be the first manifestation of diabetes mellitus but also central diabetes insipidus, the latter linked to cerebral tumors, metastases in the hypothalamus, granulomatous disease, but also nephrogenic diabetes insipidus such as chronic renal disease or autoimmune disease. Intracellular dehydration is the major risk in case of a polyuropolydipsic syndrome. Prognosis depends on the capacity to maintain water balance through an intact thirst mechanism. After a brief review of the majority of causes of diabetes insipidus, we propose a diagnosis algorithm to easily make the diagnosis.

[The drug of the month: a new antihypertensive association: Preterax, low doses of ACE inhibitor and thiazide in the same pill]

Preterax is the first fixed very- low - dose combination of an angiotensin--converting enzyme inhibitor and a diuretic for first line treatment of hypertension. Its antihypertensive efficacy is remarkable due to the presence of 2 drugs with additional effects. The tolerance is also excellent, with adverse effects similar to placebo. The 24 h blood pressure control is maintained. If necessary, the dose can be doubled (BiPreterax). The medical practitioner must keep in mind that it is an association of perindopril 2 mg and indapamide 0.625 mg with their own contra-indications. These low dose associations are now recommended as one of the 2 options to initiate an antihypertensive drug treatment, with the hope of an improvement in the percentage of well controlled blood pressure in the hypertensive population. Let us remember that the blood pressure target to be reached is at least < 140/90 mmHg. Up till now, no antihypertensive class has demonstrated a superiority over the others. Only the blood pressure fall magnitude is important to prevent cardiovascular complications.

[The drug of the month: Olmesartan medoxomil]

Olmesartan medoxomil (Belsar, Olmetec) developed by Sankyo Pharma and proposed by Sankyo Pharma but also Menarini is a new angiotensin II ATI receptor blocker. Its indication is the treatment of hypertension. Olmesartan is indeed an antihypertensive agent with an efficacy dependent on the dose from 10 to 40 mg. It is taken once a day, because of a long duration of action. This prodrug has a dual elimination pathway (biliary and renal). The contraindications are the same as for the other sartans. One of its main advantage, besides its rapidly observed efficacy to lower high blood pressure, is its relatively low cost within this family. It has also cardiovascular and renal protective effects. The recommended usual dosage is 20 mg/day.

[Guidelines for the management of arterial hypertension in general practice]

Guidelines for the management of arterial hypertension are regularly updated. This article summarizes the last international guidelines in this field published last year. The decision to initiate an antihypertensive treatment will not only depend on blood pressure levels, but also on global cardiovascular risk assessment.

[New American and European 2003 guidelines for the management of arterial hypertension]

New American and European guidelines have been released in 2003, the purpose of which is to improve the management of arterial hypertension. The decision to treat high blood pressure now mainly relies on the individual cardiovascular risk rather than on the sole blood pressure level. Thus, antihypertensive drugs could be proposed even to normotensive individuals, provided they have a high cardiovascular risk (> 20% at 10 years). On the other hand, grade 1 or 2 hypertensive patients, if their baseline cardiovascular risk is low, will be prescribed antihypertensive drugs only after 3 to 6 months of follow-up. In all cases, individualized non pharmacological means must always be proposed and their use stimulated. The target blood pressure under treatment will be < 140/90 mmHg when the cardiovascular risk is low or moderate, but < 130/80 mmHg when high risk exists. To reach this target, a drug combination is very often necessary, and it frequently includes a low dose of diuretic. To-day, the option of using a low dose biotherapy as an alternative to monotherapy is even proposed as first step antihypertensive treatment. After initiation of treatment, the patient must be regularly followed up and stimulated to decrease his cardiovascular risk to the lowest possible level, following an inclusive approach.

[Clinical case of the month. Rapid atrial fibrillation causing ventricular tachycardia and syncope]

We report a rare case of rapid atrial fibrillation triggering an episode of ventricular tachycardia. We review the literature and discuss the potential mechanisms of the ventricular arrhythmia.

[Management of serum magnesium abnormalities]

Because symptoms associated with hypomagnesia are highly aspecific, this ionic abnormality is rarely searched for although it could be present in as much as 20% of the population. The mode of correction (oral or intravenous) depends on the etiology, severity and clinical consequences of hypomagnesemia. Significant hypermagnesemia only occurs in the presence of renal insufficiency and/or acute excess administration, mainly by the intravenous route. If interruption of administration does not suffice, renal dialysis might become necessary to quickly correct the magnesemium serum levels.

[Prevention of chronic renal failure in the adult]

Chronic renal failure is an unrecognised disease, with an insidious and rather silent development, for which the general practitioners are too often passive. This review would like to insist on the detection of people at risk or with early abnormalities, on the optimal guidelines to slowdown the evolution to more severe and irreversible stages, on the prevention of uremic and cardiovascular complications and on the preparation to end stage renal treatments.

[Can arterial hypertension be prevented?]

Prevalence of arterial hypertension is growing, in particular due to population ageing. Hypertension is a major risk factor for cardiovascular morbidity and mortality. Prevention is conceivable on a theoretical basis by reduction or, if possible, prevention of excess weight, diet modifications, increased physical activity among other means. To be efficient, prevention should include an early detection of patients at risk and a long term assessment of efficacy requiring many efforts from both patients and physicians.

[Abnormalities in serum magnesium concentration]

Magnesium (Mg) therapy is often proposed against stress and to correct asthenia. Thus our aim has been to review the role of Mg, the mechanisms of its homeostasis before detailing the clinical presentations and etiologies of hypo- and hypermagnesemia and their exploration. Hypomagnesemia frequently occurs but is clinically rarely recognized without biological serum ionic determinations because causing atypical signs miming those of other ion deficiencies. Hypermagnesemia is uncommon but often occurs in the presence of renal insufficiency especially with excess of Mg administration.

[Evaluation of glomerular filtration rate in clinical practice]

Glomerular filtration rate (GFR) is the most frequently used parameter to evaluate the renal function. GFR may be estimated with serum creatinine, creatinine clearance based on 24 hours urine collection or Cockcroft formula. All these methods have bias. Other approaches have thus been proposed. The limitations and advantages of isotopic methods and recent mathematical approaches (MDRD formula) are reviewed.

[Cystatin C in the evaluation of renal function]

Glomerular filtration rate (GFR) is the best indicator of renal function. GFR is usually estimated by serum creatinine or the creatinine clearance calculated on urine collected over 24 hours or with the Cockcroft formula. These methods are however limited. Serum creatinine has a very poor sensitivity and urine collection is difficult. Cystatin C is a protease inhibitor produced in a constant manner by nucleated cells. This molecule is freely filtrated by the glomerule and quite completely catabolized in the proximal tubules. Its plasmatic concentration might thus be used to estimate GFR. Presently available data allow to conclude that plasmatic cystatin C is at least as good as serum creatinine to estimate GFR. It is less sensible to changes in body mass. Its determination appears more sensitive to detect early mild changes in GFR. Reference values are presently available for the different methods of determination. Cystatin C plasma level determination is more expensive than routine creatinine plasma determination. In the absence of very significant advantages, this might explain its limited use in daily clinical practice.

[Clinical study of the month. Which initial antihypertensive? Results from the ALLHAT trial]

Antihypertensive therapy is well established to reduce hypertension-related morbidity and mortality, but the optimal first-step therapy is still controversial. The "Antihypertensive and Lipid-Lowering Treatment to Prevent Heart Attack Trial" (ALLHAT) should give such an answer. It is a randomised, double-blind, trial designed to determine whether treatment with either a calcium channel blocker or an angiotensin-converting enzyme inhibitor lowers the incidence of coronary heart disease (CHD) or other cardiovascular disease (CVD) events vs treatment with a diuretic. A total of 33,357 participants aged 55 years or older with mild to moderate hypertension and at least 1 other CHD risk factor were randomly assigned to receive chlorthalidone (12.5 to 25 mg/day; n = 15,255), amlodipine (2.5 to 10 mg/day; n = 9,048) or lisinopril (10 to 40 mg; n = 9,054). The primary outcome combined both fatal CHD and non-fatal myocardial infarction, analyzed by intent-to-treat. Secondary outcomes were all-causes mortality, stroke, combined CHD (primary outcome, coronary revascularization, or angina with hospitalization), and combined CVD (combined CHD, stroke, treated angina without hospitalization, heart failure and peripheral arterial disease). Chlorthalidone was slightly more effective in reducing systolic pressure while amlodipine reduced slightly more effectively diastolic blood pressure. After a mean follow up of 4.9 years, no differences were observed between the three treatments regarding both the primary outcome and the total mortality. Secondary outcomes were similar when comparing amlodipine vs chlorthalidone. A moderately higher 6-year incidence rate of clinically detected heart failure was observed with amlodipine, but without significant influence on mortality. For lisinopril vs chlorthalidone, lisinopril had slightly higher 6-year rates of combined CVD, stroke and heart failure. In conclusion, thiazide-type diuretics are superior in preventing one or more major forms of CVD and offer the advantage to be cheaper. They should be preferred for first-step antihypertensive therapy. However, to reach the recommended blood pressure target, most patients should receive a combination of antihypertensive compounds. Such a combination should always comprise a diuretic agent, in absence of contra-indications.

Belgian peer review experience on the Achille's Heel in haemodialysis care: vascular access

AIMS

In order to improve the supervision and to evaluate the quality of care in dialysis units, a national project was promoted as a Peer Review. It consisted of systematic, continuous and critical evaluation of the care and the application of international guidelines and compared the reality of care with standards.

METHOD

The first chart consisted of the evaluation of infectious episodes of vascular access. This point is particularly relevant since infection represents the second cause of mortality in haemodialysis. A questionnaire concerning each patient was designed. Questions concerned the description of vascular access and the related infectious events. Each questionnaire included 21 items. The project involved 29 dialysis centres, 1,644 patients and 1,775 vascular accesses. The database included 90,525 data.

RESULTS

Among the 29 centres, the native arteriovenous fistula (AVF) is the first choice (67.5%) in vascular access, but the proportion of AVF decreases with age contrary to the catheter, which is more frequently chosen, in older patients. Independent of age, 20% of hospitalisations are among patients with catheters and only 7% among patients with AVF. The RR (relative risk) of being hospitalised (any complication of vascular access) is 1.68 for patients with catheters compared to patients with AVF. The rate of infections does not increase with age but is higher for patients with catheters (RR = 2.26). The number of infections appears to be dependent on the staphylococcus aureus carriage in the year.

CONCLUSIONS

This first step allows each centre to compare itself to others in an anonymous way. This approach should lead to specific recommendations to improve the quality of care in dialysis units.

[Cardiac decompensation, renal function and non-steroidal anti-inflammatory agents]

Thanks to a case report of heart failure in an old people with a cardiovascular history treated by the new coxib-inhibitors, we would like to remember and insist to the risk of renal and cardiac complications which appear to be the same as those with the non specific antiinflammatory drugs. Old age, diuretic or converting enzyme inhibitor treatment, heart failure, liver insufficiency, nephrotic syndrome are risk factors for acute renal failure and cardiac failure during such treatment.

[Arterial hypertension and tachycardia: monitoring the patient's personal drug therapy]

The case report of a young patient with an increase in blood pressure and heart rate offers the opportunity to discuss the clinical guidelines to explore and treat high blood pressure. The value of the 24 h blood pressure monitoring and the need for precise information on all drugs taken are stressed.

[How I investigate...a refractory hypertension]

Hypertension is a cardiovascular risk factor which needs a good evaluation before treatment. When this latter is decided, the target is to normalize high blood pressure. This requires a complete information of the patient; the latter will also receive individualized non pharmacological advices and, also, possibly different antihypertensive drugs. When blood pressure does not normalize, one must check the blood pressure measurement technique, the compliance to treatment and potential pharmacologic interferences. Secondary hypertension is only considered if resistance to therapy cannot be found. It should be remembered that obesity and sleep apnea disorders are responsible of many instances of refractory hypertension.

Diagnostic criteria for renovascular hypertension

Renovascular hypertension is a clinical situation characterized by high blood pressure in the presence of renal ischemia mainly related to atherosclerotic or fibromuscular dysplasic narrowing of the renal artery (ies). This diagnosis is often "a posteriori" validated, because the discovery of a significant renal artery stenosis is not obligatory responsible of the blood pressure elevation. This article proposes a diagnostic strategy for exploring patient with this suspected secondary cause of hypertension before proposing an invasive approach (intra-arterial angiography) possibly followed by a revascularization. However, the methods for exploring such population are mainly based on patient characteristics and local expertise and habits. These must thus be individualized. First, clinical symptoms or signs frequently associated with hypertension and renal artery stenosis must be searched. If present, a non invasive and functional exploration of the renal arteries is to be proposed (Captopril radioisotope renography, colour duplex sonography) followed by magnetic resonance angiography or spiral computer tomography angiography if the clinical suspicion index is moderate or high. If this is very high, an intra-arterial arteriography could immediately be performed if not too dangerous. On the opposite site, if the clinical index is low, it is recommended to follow clinically and to treat risk factors.

[Hypertension and arteriopathy]

High blood pressure as other factors of atherosclerosis is a well-known risk factor for development of peripheral arterial disease. A patient characterized by an isolated systolic hypertension and a low ankle/arm systolic blood pressure ratio very often presents coronary heart disease. Practising exercise (such as walking), stoping smoking and following an adapted diet are recommended. Hypertension treatment must be considered as a secondary prevention approach with a blood pressure normalisation as a target. All the different classes of antihypertensive drugs can be used, but with a marked preference for angiotensin converting enzyme (with caution for the renal artery stenosis risk) and for betablockers to improve the potential coronary heart disease (care is needed in the presence of severe peripheral arterial disease).