Kidney Disease
Terminology
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CRF: Chronic Renal Failure
ARF: Acute Renal Failure
ESRD: End stage renal disease
ESRF: End stage renal failure
GFR: Glomular filtration rate
Azotemia: Retention of nitrogenous waste
products as renal insufficiency develops
The Kidney
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Three of the biggest jobs that the kidneys have are:
(1) to cleanse the blood,
(2) to regulate and maintain an appropriate fluid and
chemical balance in the body, and
(3) to produce the urine.
Each of these functions is closely related to the other two,
not only because each involves the removal or addition of
fluid and chemicals from the blood, but also because each
of these functions takes place in the kidney's nephrons.
The starting point in the nephron for each of these
functions is the glomerulus. It is the "gateway" that the
blood must pass through in order to be cleansed by the
kidneys.
The Kidney
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There are 1 million nephrons in each kindey
The kidney has an innate ability to maintain
GFR by hyperinfiltration and compensatory
hypertophy of the remaining healthy
nephrons
Acute Renal Failure
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is a rapidly progressive loss of renal function, generally
characterized by oliguria (decreased urine production,
quantified as less than 400 mL per day in adults, less than
0.5 mL/kg/h in children or less than 1 mL/kg/h in infants);
and fluid and electrolyte imbalance. AKI can result from a
variety of causes, generally classified as prerenal, intrinsic,
and postrenal. An underlying cause must be identified and
treated to arrest the progress, and dialysis may be
necessary to bridge the time gap required for treating these
fundamental causes
Causes of ARF
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Prerenal causes of AKI are those that decrease effective blood flow to
the kidney. These include systemic causes, such as low blood volume,
low blood pressure, and heart failure, as well as local changes to the
blood vessels supplying the kidney (clots, stenosis…)
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Sources of damage to the kidney itself are dubbed intrinsic. Intrinsic
can be due to damage to the glomeruli, renal tubules, or interstitium.
Common causes of each are glomerulonephritis, acute tubular necrosis
(ATN), and acute interstitial nephritis (AIN), respectively
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Postrenal is a consequence of urinary tract obstruction. This may be
related to benign prostatic hyperplasia, kidney stones, obstructed
urinary catheter, bladder stone, bladder, ureteral or renal malignancy
Chronic Renal Failure
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The most common causes of CKD are
diabetes mellitus, hypertension, and
glomerulonephritis.Together, these cause
approximately 75% of all adult cases
http://www.youtube.com/watch?v=ikGl7DPX
UK0&feature=related
Chronic Renal Failure
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Presence of markers of kidney damage for three
months, as defined by structural or functional
abnormalities of the kidney with or without
decreased GFR, manifest by either pathological
abnormalities or other markers of kidney damage,
including abnormalities in the composition of blood
or urine, or abnormalities in imaging tests.
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The presence of GFR <60 mL/min/1.73 m2 for
three months, with or without other signs of kidney
damage as described above.
Am J Kidney Dis 2002; 39:S1
Diabetes
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A group of metabolic diseases in which a person has high blood sugar,
either because the body does not produce enough insulin, or because
cells do not respond to the insulin that is produced. This high blood
sugar produces the classical symptoms of polyuria (frequent urination),
polydipsia (increased thirst) and polyphagia (increased hunger).
There are three main types of diabetes:
Type 1 diabetes: results from the body's failure to produce insulin, and
presently requires the person to inject insulin.
Type 2 diabetes: results from insulin resistance, a condition in which
cells fail to use insulin properly, sometimes combined with an absolute
insulin deficiency.
Gestational diabetes: is when pregnant women, who have never had
diabetes before, have a high blood glucose level during pregnancy. It
may precede development of type 2 DM.
GFR
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Volume of fluid filtered from the renal glomerular capillaries into the
Bowman's capsule per unit time.
Glomerular filtration rate (GFR) can be calculated by measuring any
chemical that has a steady level in the blood, and is freely filtered but
neither reabsorbed nor secreted by the kidneys. The rate therefore
measured is the quantity of the substance in the urine that originated
from a calculable volume of blood
The GFR test measures how well your kidneys are filtering a waste
called creatinine, which is produced by the muscles. When the kidneys
aren't working as well as they should, creatinine builds up in the blood.
Stages of CKD
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Stage 1*: GFR >= 90 mL/min/1.73 m2
 Normal or elevated GFR
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Stage 2*: GFR 60-89 (mild)
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Stage 3: GFR 30-59 (moderate)
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Stage 4: GFR 15-29 (severe; pre-HD)
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Stage 5: GFR < 15 (kidney failure)
Am J Kidney Dis 2002; 39 (S2): S1-246
Epidemiology
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19 million Americans have CKD
Approx 435,000 have ESRD/HD
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Annual mortality rate for ESRD: 24%
Am J Kidney Dis 2002; 39(S2): S1-246
Signs & Symptoms
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General
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 Fatigue & malaise
 Edema
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 Anorexia
 Nausea/vomiting
 Dysgeusia
Ophthalmologic
 AV nicking
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HTN
Heart failure
Hyperkalemia
Pericarditis
CAD
Skin
 Pruritis
 Pallor
Cardiac
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GI
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Neurological
 MS changes
 Seizures
Uremia
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Is the clinical and laboratory syndrome,
reflecting dysfunction of all organ systems
as a result of untreated or undertreated
acute or chronic renal failure
Changes in the blood
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The kidneys work to filter toxins and waste
products out of the blood. When kidney
function declines, waste products begin to
build up within the blood. Creatine and urea
build up. Phosphate also accumulates in the
blood. A build up of hydrogen ions may also
occur, leading to acidosis.
Changes in electrolytes
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Because of the resulting changes to the
blood chemistry, the electrolyte balance of
the blood and cells is disrupted. Fluid
retention also results. Often fluid retention is
the first noticeable sign that the kidneys are
beginning to shut down. The resulting water
weight gain and edema in the hands and
feet signal that the kidneys are not removing
waste products and fluids as they should.
Pulmonary Edema
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as acute renal failure worsens, fluids continue to
build within the body and may begin to collect in
the air sacs of the lungs. This condition, known as
pulmonary edema, can result in difficulty
breathing, restlessness, anxiety and wheezing.
Untreated pulmonary edema can ultimately lead to
respiratory failure. Most deaths that occur in cases
of renal failure are due to either a systemic
infection or respiratory failure that results from the
initial failure of the kidneys.
Why does edema occur in
patients with kidney disease?
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Edema forms in patients with kidney disease
for two reasons:
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a heavy loss of protein in the urine, or
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impaired kidney (renal) function.
Heavy loss of protein in the
urine
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The heavy loss of protein in the urine (over 3.0
grams per day) with its accompanying edema is
termed the nephrotic syndrome. Nephrotic
syndrome results in a reduction in the
concentration of albumin in the blood
(hypoalbuminemia). Since albumin helps to
maintain blood volume in the blood vessels, a
reduction of fluid in the blood vessels occurs. The
kidneys then register that there is depletion of
blood volume and, therefore, attempt to retain salt.
Consequently, fluid moves into the interstitial
spaces, thereby causing pitting edema.
Heavy loss of protein in the
urine
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The treatment of fluid retention in these
patients is to reduce the loss of protein into
the urine and to restrict salt in the diet. The
loss of protein in the urine may be reduced
by the use of ACE inhibitors and angiotensin
receptor blockers (ARB's). Both categories
of drugs, which ordinarily are used to lower
blood pressure, prompt the kidneys to
reduce the loss of protein into the urine.
Impaired kidney (renal)
function
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Patients who have kidney diseases that impair
renal function develop edema because of a
limitation in the kidneys' ability to excrete sodium
into the urine. Thus, patients with kidney failure
from whatever cause will develop edema if their
intake of sodium exceeds the ability of their
kidneys to excrete the sodium. The more
advanced the kidney failure, the greater the
problem of salt retention is likely to become. The
most severe situation is the patient with end-stage
kidney failure who requires dialysis therapy.
Management
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Identify and treat factors associated with
progression
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HTN
Proteinuria
Glucose control
Treat pulmonary edema (Bipap)
Hypertension
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Target BP
 <130/80 mm Hg
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Consider several anti-HTN medications with
different mechanisms of activity
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ACEs/ARBs
Diuretics
CCBs
HCTZ (less effective when GFR < 20)
Metabolic changes with CKD
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Hemoglobin/hematocrit 
Bicarbonate 
Calcium
Phosphate 
PTH 
Triglycerides 
Metabolic changes…
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Monitor and treat biochemical abnormalities
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Anemia
Metabolic acidosis
Mineral metabolism
Dyslipidemia
Nutrition
Anemia
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Common in CRF
HD pts have increased rates of:
 Hospital admission
 CAD/LVH
 Reduced quality of life
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Can improve energy levels, sleep, cognitive
function, and quality of life in HD pts
Treating Anemia
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Epoetin alfa (rHuEPO; Epogen/Procrit)
 HD: 50-100 U/kg IV/SC 3x/wk
 Non-HD: 10,000 U qwk
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Darbepoetin alfa (Aranesp)
 HD: 0.45 g/kg IV/SC qwk
 Non-HD: 60 g SC q2wks
Metabolic acidosis
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Muscle catabolism
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Metabolic bone disease
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Sodium bicarbonate
 Maintain serum bicarbonate > 22 meq/L
 0.5-1.0 meq/kg per day
 Watch for sodium loading
 Volume
 HTN
expansion
Mineral metabolism
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Calcium and phosphate metabolism
abnormalities associated with:
 Renal osteodystrophy
 Calciphylaxis and vascular calcification
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14 of 16 ESRD/HD pts (20-30 yrs) had
calcification on CT scan
3 of 60 in the control group
NEJM 2000; 342(20): 1478-83
Nutrition
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Think about uremia
 Catabolic state
 Anorexia
 Decreased protein intake
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Consider assistance with a renal dietician
CV disease
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70% of HD patients have concomitant CV
disease
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Heart disease leading cause of death in HD
patients
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LVH can be a risk factor
Kidney Int 1995; 47(1): 186-92
Acid Base Balance
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http://www.youtube.com/watch?v=i_pTaTve
CCo&feature=related