December
2005
Volume 2, Issue
3
Table
of contents:
From the editor
Editorial
Meet
the team
Dr
Sijmen Arend
Duursma
Original
Contribution/Clinical Investigation
Increased
leukocyte
rigidity in the elderly
Parkinson's
disease
and related movement disorders
Models
and Systems
of Elderly Care
Study
of Relation
between Knowledge,
Attitude and Practice
of the Elderly with
Their General Health in
Tehran
Education
and
Training
Renal
Failure
Conference
5th European
Congress of
Biogerontology
Abdulrazak
Abyad MD,
MPH, MBA,
AGSF
Editorial office:
Abyad Medical Center &
Middle East Longevity
Institute
Azmi Street, Abdo Center,
PO BOX 618
Tripoli, Lebanon
Phone: (961) 6-443684
Fax: (961) 6-443685
Email:
aabyad@cyberia.net.lb
Lesley Pocock
medi+WORLD International
572 Burwood Road,
Hawthorn 3122
AUSTRALIA
Phone: +61 (3) 9819 1224
Fax: +61 (3) 9819 3269
Email:
lesley@mediworld.com.au
Renal Failure
Andrew comes in requesting a 'thorough going over' as his brother recently died from an AMI. You decide to check his renal function amongst his investigations and to your surprise his serum creatinine is 210 umol/? (0.21 mmol/L) [normal <120 umol/L].
You have
no record of a previous level.
| 1. Question | Answer |
|
You decide to follow this up with some further tests. Which of the following would be useful: Click on the above items for feedback |
MSU |
We determine that Andrew has stable renal impairment, with a serum creatinine on repeat testing of 205 umol/L.
A dipstick
showed only +protein and no blood and a follow-up MSU was unremarkable.
The ECG showed some latheral T wave incersion consistent with 'ischaemia
or a strain pattern'.
| 2. Question | Answer |
|
You
decide to image his Click on the above items for feedback |
Renal ultrasound |
The kidneys are a little small (right 9.5 cm, left 9 cm) but there is no other abnormality found. It appears likely that Andrew has chronic renal impairment with no reversable component. A Nephrologist feels that he has advanced nephrosclerosis (the not so beginning of the end of the spectrum of benign nephrosclerosis) as a result of his long history of hypertension and other vascular risk factors. He has been advised that his kidneys will continue to deteriorate over the next 3-6 years, at which point he will probably need dialysis.
| 3. Question | Answer |
|
What are the factors that will influence his rate of progression over the next few years? Select
one only.
Click on the above items for feedback |
Tight blood pressure control |
As Andrew’s renal failure progresses he will also need attention to the following factors.
Control
of calcium and phosphate
High phosphate levels may cause itch but more importantly will slowly
cause deterioration in Andrew's bones with the developement of 'renal
osteodystrophy'. Control of phosphate with phosphate binders such as calcium
carbonate and the later introduction of calcitriol are likely to be needed.
Control
of anaemia
Most patients
with renal failure develop anaemia (except for about half of the patients
with polycystic kidneys). This is usually not related to levels of iron,
B12 or folate, although deficiencies of these need to be excluded. Usually
this anaemia responds to erythropoietin (or EPO) therapy. EPO is given
as a subcutaneous injection, once or twice a week and the patients nearly
always require supplemental iron therapy, often even intravenous iron
therapy, due to the high induced levels of red cell production. Correcting
the anaemia improves many of the symptoms of advanced renal failure and
may help protect the heart from left ventricular hypertrophy.
Ongoing
control of his blood pressure, diet and lipids.
Deterioration
in BP control can quickly translate into a rapid decline in renal function.
Preparation
for dialysis, and if appropriate, transplantation (probably not in this
case)
Preparation
for dialysis involves an extensive education programme, construction of
an AV fistula in the forearm, and maintenance of otherwise good general
health. Poorly controlled ischaemic heart disease in particular makes
dialysis difficult.
Once on dialysis, Andrew has a mortality rate of about 13-16% per year (or about 15-20 deaths per 100 patient years). This figure is much higher if he happens to have diabetes.
| A
strict low-protein diet
Low-protein diets have been through several phases. Low-protein diets certainly reduce the symptoms of more advanced renal failure (or more specifically 'uraemia') but will not have such benefit for Andrew. The average Australian diet contains 1-1.5 gm/kg of protein per day. Restricting this to about 0.7 gm/kg day may well help slow the rate of progression of his renal failure (Click here to view Figure). However, a prolonged period of time on a low-protein diet, especially if not closely supervised, may result in some degree of malnutrition and thus moderate protein restriction only is usually recommended (e.g. 0.8 gm/kg/day). With more advanced renal impairment, patients often autorestrict their protein intake via a loss of appetite. Renal Function vs Time
In
most renal conditions renal function deteriorates at a steady rate.
The use of antihypertensives and to a lesser extent, low protein
diets, slows this rate of deterioration. |
| Total
avoidance of salt
Avoidance of salt is a useful adjunct to BP control. How far do you go? Patients should be warned that it takes at least 4-6 weeks to become accustomed to a very low salt diet. If this is tolerated, well and good, but many patients end up eating very little under this restriction and are probably better off eating some salt. It should also be remembered that some renal conditions result in salt (and water) wasting, especially predominantly tubular disorders such as analgesic nephropathy and reflux nephropathy (whereas the glomerular disorders tend to retain salt and water). A diuretic may be an alternative to a low salt diet. |
|
There is no question that tight blood pressure control is very important (Click here to view Figure). We have known for some time that the rate of progression of renal failure due to most renal diseases is slowed by blood pressure control. Recent trials have confirmed this and suggested even tighter margins with lower target blood pressures. Target levels close to 120-130/80-85 should be kept in mind. Renal Function vs Time
In most renal conditions renal function deteriorates at a steady rate. The use of antihypertensives and to a lesser extent, low protein diets, slows this rate of deterioration. |
| Absolute
requirement for an ACE-Inhibitor
ACE-Inhibitors appear to offer benefit over and above simple blood pressure control, compared to other antihypertensive agents. Having said this some recent trials have suggested that if blood pressure control is tight then the differences are less and that other antihypertensive agents (especially beta-blockers) may offer equal benefits. Most nephrologists currently prefer to use ACE-Inhibitors as a first choice but accept other agents as good alternatives if ACE-Inhibitors can't be used (e.g. due to renal artery stenosis, rising creatinine, hyperkalaemia, drug reactions, cough). Angiotensin-II receptor blockers may offer similar benefits to ACE-Inhibitors but there is not enough data available yet to confirm this. |
| Maintaining
a low cholesterol
Maintaining a low cholesterol is probably beneficial. This issue has not been addressed in a large-scale manner specifically in terms of rate of progression of renal failure. However, we know that progression is at least in part related to intra-renal haemodynamics and the state of the intra-renal vasculature. Diminishing any deterioration in the state of these vessels will be helpful and so the nephrologists have 'borrowed' these concepts from the cardiologists. Exact target levels have not been defined but prudence suggests that a total cholesterol below 5.0 mmol/l would be wise. |
