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 Dialysis Complications of Chronic Renal Failure

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PostSubject: Dialysis Complications of Chronic Renal Failure    Mon Jun 13, 2011 5:31 pm

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Dialysis Complications of Chronic Renal Failure

Overview


The
population of patients receiving dialysis in the United States is large
due to universal government funding for treatment of end-stage renal
disease (ESRD), and patients with ESRD are encountered on a regular
basis in US emergency departments. According to one estimate in 2001, of
patients with ESRD in 2010, 520,240 would be dialysis patients, and the
forecasted Medicare expenditures were projected to increase to $28.3
billion by 2010.[1] As
of the first quarter of 2009, there was an actual prevalence of
561,454, which reflects a decreasing incidence compared with the earlier
projection. Various problems are related to vascular access in
patients on hemodialysis and to abdominal catheters in patients using
continuous ambulatory peritoneal dialysis (CAPD). These vascular access
complications are similar to those seen in any patient with a vascular
surgical procedure (eg, bleeding, local or disseminated intravascular
infections [DIC], vessel [graft] occlusion). The native peripheral
vascular system is also affected with higher rates of amputation and
revascularization procedures, and a peritoneal dialysis catheter
subjects patients to the risks of peritonitis
and local infection, because the catheter acts as a foreign body and
provides a portal of entry for pathogens from the external environment. For more information, see Chronic Renal Failure.
Next Section: Electrolyte Abnormalities

Electrolyte Abnormalities

Electrolyte abnormalities may result from renal disease itself or as an iatrogenic complication.
Hyperkalemia

Hyperkalemia
is the most common clinically significant electrolyte abnormality in
chronic renal failure. This condition is uncommon when patients with
end-stage renal disease (ESRD) are compliant with treatment and diet,
unless an intercurrent illness such as acidosis or sepsis develops. A
history of hyperkalemia requiring treatment or poor compliance with
treatment should lower the threshold for ordering a potassium level. Serum
potassium levels usually should be measured in patients with chronic
renal failure or ESRD who present with a systemic illness or major
injury. Serum potassium rises when the serum is acidemic, even though
total body potassium is unchanged. Hyperkalemia is usually asymptomatic
and should be treated empirically when suspected and when arrhythmia or
cardiovascular compromise is present. Electrocardiography (ECG)
may be useful in diagnosis of suspected hyperkalemia. Severely peaked T
waves are a relatively specific finding, although this is not a very
sensitive test for hyperkalemia in the setting of chronic renal failure.
Widening of the QRS complex indicates severe hyperkalemia and must be
treated aggressively and rapidly. Similar "hyperacute" T-waves may be
seen early in acute MI. The ECG below shows large T

waves and wide QRS complex.



The
tracing shows a wide QRS and very large T waves. In the setting of a
minimally symptomatic patient with renal failure, this must be treated
as hyperkalemia until the potassium level is not elevated. Hyperkalemia
may be completely asymptomatic until a lethal arrhythmia occurs. Calcium
salts are the most rapid acting of the agents used to treat
hyperkalemia.
Hyponatremia, hypocalcemia, and hypermagnesemia

Iatrogenic
complications related to fluid administration (fluid overload) or
medications are frequently encountered in patients in renal failure.
Dilutional hyponatremia may cause mental status changes or seizures. Hypocalcemia or hypermagnesemia
may cause weakness and life-threatening dysrhythmias. Neuromuscular
irritability is seen with hypocalcemia and may present as tetany or
paresthesia. Hypermagnesemia causes neuromuscular depression with
weakness and loss of reflexes. Acidosis may present as shortness of
breath due to the work of breathing from compensatory hyperpnea.
Previous

Dialysis Dysequilibrium Syndrome

Dialysis
dysequilibrium syndrome is a common neurologic complication seen in
dialysis patients that is characterized by weakness, dizziness,
headache, and in severe cases, mental status changes. The diagnosis is
one of exclusion; a prime characteristic of this syndrome is that it is
nonfocal.
Previous

Infection

Patients
with an arteriovenous fistula or graft should have the site examined
regularly. Vascular access problems include infections, which are
usually manifest with typical signs and symptoms such as local pain,
redness, warmth, or fluctuance. Fever may be present without local
signs. Clotting of the vascular access presents as loss of normal bruit
or palpable thrill. There may be signs or symptoms of distal limb
ischemia.
CAPD-associated peritonitis

Peritonitis
is common in patients who are being treated with CAPD, occurring
approximately once per patient year. Patients present with generalized
abdominal pain, which may be mild, or complain of a cloudy effluent.
Localized pain and tenderness suggest a local process, such as
incarcerated hernia or appendicitis. Severe generalized peritonitis may
be due to a perforated viscus as in any other patient. Fever is often
absent. The diagnosis of CAPD-associated peritonitis is confirmed
by culture of effluent dialysate (ie, peritoneal fluid), which should
be ordered before empiric treatment. Presumptive diagnosis is based on a
peritoneal fluid white blood cell (WBC) count of greater than 100/mL or
a positive Gram stain. The effluent is often cloudy when peritonitis is
present, and this appearance accurately predicts elevated WBC counts.
In patients without peritonitis, WBC counts of 0-50/mL with a
mononuclear predominance are considered normal. Cell counts are usually
much higher with predominant polymorphonuclear neutrophils (PMNs) when
peritonitis is present.
Previous
Next Section: Electrolyte Abnormalities

Hemorrhage

Patients
may present after dialysis or minor trauma with bleeding from their
vascular access site. Active bleeding can also occur from the incisional
wound of a newly placed fistula or graft. The bleeding can usually be
controlled with elevation and firm but nonocclusive pressure. In the
immediate postdialysis period, protamine may be needed to reverse the
effect of heparin (routinely used in dialysis to prevent clotting). Note
that life-threatening bleeding may occur. Anemia is inevitable
in chronic renal failure because of loss of erythropoietin production.
Abnormalities in white cell and platelet functions lead to increased
susceptibility to infection and easy bleeding and bruising. This
condition results in fatigue, reduced exercise capacity, decreased
cognition, and impaired immunity.
Vascular access aneurysms or pseudoaneurysms

Aneurysms
or pseudoaneurysms may form and progressively enlarge to compromise the
skin overlying the site of venous access. These present as localized
swelling, which may be pulsatile, and are often chronic. A rapid
increase in size may indicate active bleeding.
Previous
Next Section: Electrolyte Abnormalities

Treatment and Management Considerations

Peripheral
hemodialysis access sites may be used to draw blood or infuse
medications and fluids in an emergency when no other access is
available. A central venous access device may be used with the usual
precautions. In an immediately life-threatening emergency, the following
procedure may be used. The site should not be used for routine
intravenous access.

  • Do not use a tourniquet.
  • Avoid puncturing the back wall of the vessel.
  • Carefully
    secure all intravenous (IV) catheters; infusions may need to be under
    pressure because of relatively high pressures at the access site.
  • Apply firm but nonocclusive pressure for 10-15 minutes after accessing a peripheral hemodialysis access site.
  • Document presence of a thrill before and after procedure.
Consider consultation with a nephrologist and/or vascular surgeon for the following problems:

  • Need for urgent dialysis
  • Significant deterioration from baseline renal function
  • CAPD-associated peritonitis or catheter-associated infection
  • Infection, obstruction, or expanding aneurysm/pseudoaneurysm of the vascular access
Other problems that may arise in the dialysis patient include the following:

  • Changes in calcium and phosphorus metabolism, acidosis
  • Lipid disorders
  • Pericarditis
  • Serositis
  • Gout, pseudogout
  • Hypothyroidism, seizures, fractures
  • Accelerated hypertension
  • Infertility, impotence, spontaneous abortion
  • Bleeding, gastrointestinal mucosal ulcerations, arteriovenous malformations
Hypotension and Shock

Hypotension
in dialysis patients may be due to any of the causes encountered in any
other patient. Consider serious causes such as bleeding, cardiac
dysfunction, and sepsis. While ruling out more serious causes, IV
isotonic saline in small bolus doses (approximately 200 mL) may be used
for treatment. IV fluids should not be administered except for
cases of frank shock. When used, the preferred regimen is small bolus
doses (approximately 200-250 mL) with reevaluation for effect between
doses. Lactated Ringer solution should not be used because of the
potassium content.
Cardiac Dysfunction

Cardiac arrest in a
patient with chronic renal failure or ESRD may be due to hyperkalemia.
Consider treatment with IV calcium and IV bicarbonate while awaiting
laboratory confirmation. Nebulized albuterol may also be used for
temporary lowering of serum potassium levels, when appropriate. Consider
pericardial tamponade, especially in the setting of pulseless
electrical activity (PEA). If tamponade is suspected, consider
pericardiocentesis. Nitrates (oral or topical) can be temporarily effective for patients with fluid overload.
Hemorrhage


Bleeding
may be due to uremic coagulopathy or from anticoagulation during
hemodialysis. In the latter case, the heparin effect may be reversed
with protamine. Desmopressin (DDAVP) by nasal, subcutaneous, or IV
routes and cryoprecipitate are effective in correction of uremic
coagulopathy. Applying firm but nonocclusive pressure for 10-15 minutes
best treats bleeding from a vascular access site. Infection and Peritonitis

CAPD-associated
peritonitis is often treated with a loading dose of parenteral
antibiotic, followed by a period of intraperitoneal antibiotics. A
systematic review found that IV antibiotics are not needed.[2] Institutions
that treat CAPD patients may have a standard protocol for treatment. In
most cases, the patient's nephrologist should be consulted, especially
if there is no institutional consensus on optimal treatment. When there
is also evidence of local infection around the catheter, systemic
antibiotics should be used.
Previous
Next Section: Electrolyte Abnormalities

Outcome of Patients on Dialysis

The
mortality rate of dialysis patients is approximately 20% despite
careful attention to fluid and electrolyte balance or other treatment.
More than 30% of patients who begin dialysis die within the first year
of the initiation of treatment. The most common cause of sudden death in
patients with ESRD is hyperkalemia, which is often encountered in
patients after missed dialysis or dietary indiscretion. In addition, the
cardiovascular mortality is 10-20 times higher in dialysis patients
than in the normal population. All-cause mortality in dialysis patients
older than 65 years is more than 6 times the general population.[3] The
morbidity and mortality of dialysis patients is much higher in the
United States compared with most other countries, which s is probably a
consequence of selection bias. Due to liberal criteria for receiving
government-funded dialysis in the US and rationing (both medical and
economic) in most other countries, US patients receiving dialysis are on
the average older and sicker than those in other countries.

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