Dialysis Complications of Chronic Renal Failure 

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.

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.

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.

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.

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.

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.

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.

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.

For more information, see Chronic Renal Failure.