Chapter 47: Acute Renal Failure and Chronic Kidney Disease
Renal failure is the partial or complete impairment of kidney function resulting in an
inability to excrete metabolic waste products and water.
Renal failure causes functional disturbances of all body systems.
Renal failure is classified as acute or chronic.
ACUTE RENAL FAILURE (ARF)
Acute renal failure (ARF) usually develops over hours or days with progressive
elevations of blood urea nitrogen (BUN), creatinine, and potassium with or without
oliguria. It is a clinical syndrome characterized by a rapid loss of renal function with
ARF is often associated with oliguria (a decrease in urinary output to <400 ml/day).
The causes of ARF are multiple and complex. They are categorized according to similar
pathogenesis into prerenal (most common), intrarenal (or intrinsic), and postrenal causes.
o Prerenal causes are factors external to the kidneys (e.g., hypovolemia) that reduce
renal blood flow and lead to decreased glomerular perfusion and filtration.
o Intrarenal causes include conditions that cause direct damage to the renal tissue,
resulting in impaired nephron function. Causes include prolonged ischemia,
nephrotoxins, hemoglobin released from hemolyzed RBCs, or myoglobin released
from necrotic muscle cells. Acute tubular necrosis (ATN) is an intrarenal
condition caused by ischemia, nephrotoxins, or pigments. ATN is potentially
reversible if the basement membrane is not destroyed and the tubular epithelium
o Postrenal causes involve mechanical obstruction of urinary outflow. Common
causes are benign prostatic hyperplasia, prostate cancer, calculi, trauma, and
Clinically, ARF may progress through four phases: initiating, oliguric, diuretic, and
recovery. In some situations, the patient does not recover from ARF and chronic kidney
disease (CKD) results, eventually requiring dialysis or a kidney transplant.
Fluid and electrolyte abnormalities and uremia occur during the oliguric phase. The
kidneys cannot synthesize ammonia or excrete acid products of metabolism, resulting in
Damaged tubules cannot conserve sodium resulting in normal or below-normal levels of
serum sodium. Uncontrolled hyponatremia or water excess can lead to cerebral edema.
Fluid intake must be closely monitored. Hyperkalemia is a serious complication of ARF. The serum potassium levels increase
because the ability of the kidneys to excrete potassium is impaired. Acidosis worsens
hyperkalemia as hydrogen ions enter the cells and potassium is driven out of the cells.
When potassium levels exceed 6 mEq/L (6 mmol/L) or dysrhythmias are identified,
treatment must be initiated immediately.
Hematologic disorders associated with ARF include anemia due to impaired
erythropoietin production and platelet abnormalities leading to bleeding from multiple
A low serum calcium level results from the inability of the kidneys to activate vitamin D.
When hypocalcemia occurs, the parathyroid gland secretes parathyroid hormone, which
stimulates bone demineralization, thereby releasing calcium from the bones. Phosphate is
also released, leading to elevated serum phosphate levels.
The two most common causes of death in patients with ARF are infection and
The best serum indicator of renal failure is creatinine because it is not significantly
altered by other factors.
Neurologic changes can occur as the nitrogenous waste products increase. Symptoms can
include fatigue and difficulty concentrating, later escalating to seizures, stupor, and coma.
The diuretic phase begins with a gradual increase in daily urine output of 1 to 3 L/day,
but may reach 3 to 5 L or more. The nephrons are still not fully functional. The uremia
may still be severe, as reflected by low creatinine clearances, elevated serum creatinine
and BUN levels, and persistent signs and symptoms.
The recovery phase begins when the GFR increases, allowing the BUN and serum
creatinine levels to plateau and then decrease. Renal function may take up to 12 months
Because ARF is potentially reversible, the primary goals of treatment are to eliminate
the cause, manage the signs and symptoms, and prevent complications while the
Common indications for dialysis in ARF are (1) volume overload; (2) elevated
potassium level with ECG changes; (3) metabolic acidosis; (4) significant change in
mental status; and (5) pericarditis, pericardial effusion, or cardiac tamponade. Hemodialysis (HD) is used when rapid changes are required in a short period of time.
Peritoneal dialysis (PD) is simpler than HD, but it carries the risk of peritonitis, is less
efficient in the catabolic patient, and requires longer treatment times. Continuous
renal replacement therapy (CRRT) may also be used in the treatment of ARF,
particularly in those who are hemodynamically unstable.
Prevention of ARF is primarily directed toward identifying and monitoring high-risk
populations, controlling exposure to nephrotoxic drugs and industrial chemicals, and
preventing prolonged episodes of hypotension and hypovolemia.
The patient with ARF is critically ill and suffers not only from the effects of renal
disease but also from the effects of comorbid diseases or conditions (e.g., diabetes,
The nurse has an important role in managing fluid and electrolyte balance during the
oliguric and diuretic phases. Observing and recording accurate intake and output and
body weight are essential.
Because infection is the leading cause of death in ARF, meticulous aseptic technique is
critical. The nurse should be alert for local manifestations of infection (e.g., swelling,
redness, pain) as well as systemic manifestations (e.g., malaise, leukocytosis) because
an elevated temperature may not be present.
Respiratory complications, especially pneumonitis, can be prevented. Humidified
oxygen; incentive spirometry; coughing, turning, and deep breathing; and ambulation
are measures to help maintain adequate respiratory ventilation.
Skin care and measures to prevent pressure ulcers should be performed because of
edema and decreased muscle tone. Mouth care is important to prevent stomatitis.
Recovery from ARF is highly variable and depends on the underlying illness, the
general condition and age of the patient, the length of the oliguric phase, and the
severity of nephron damage. Good nutrition, rest, and activity are necessary. Protein
and potassium intake should be regulated in accordance with renal function.
The long-term convalescence of 3 to 12 months may cause psychosocial and financial
hardships for the family, and appropriate counseling, social work, and psychiatrist/
psychologist referrals are made as needed. If the kidneys do not recover, the patient
will eventually need dialysis or transplantation.
The older adult is more susceptible than the younger adult to ARF as the number of
functioning nephrons decreases with age.
Causes of ARF include dehydration, hypotension, diuretic therapy, aminoglycoside
therapy, prostatic hyperplasia, surgery, infection, and radiocontrast agents. CHRONIC KIDNEY DISEASE
Chronic kidney disease (CKD) involves progressive, irreversible loss of kidney
CKD usually develops slowly over months to years and necessitates the initiation of
dialysis or transplantation for long-term survival. The prognosis of CKD is variable
depending on the etiology, patient’s condition and age, and adequacy of follow-up.
Uremia is a syndrome that incorporates all the signs and symptoms seen in the various
systems throughout the body in CKD.
In the early stage of renal insufficiency, polyuria results from the inability to
concentrate urine. As the GFR decreases, the BUN and serum creatinine levels
Clinical manifestations of uremia develop. Fatigue, lethargy, and pruritus are often the
early symptoms. Hypertension and proteinuria are often the first signs. Hyperglycemia,
hyperinsulinemia, and abnormal glucose tolerance tests may be seen.
Many patients with uremia develop hyperlipidemia, with elevated very-low-density
lipoproteins (VLDLs), normal or decreased low-density lipoproteins (LDLs), and
decreased high-density lipoproteins (HDLs).
Hyperkalemia results from the decreased excretion by the kidneys, the breakdown of
cellular protein, bleeding, and metabolic acidosis. Potassium may also come from the
food consumed, dietary supplements, drugs, and IV infusions.
Because of impaired sodium excretion, sodium along with water is retained resulting in
dilutional hyponatremia. Sodium retention can contribute to edema, hypertension, and
Metabolic acidosis results from the impaired ability to excrete the acid load (primarily
ammonia) and from defective reabsorption and regeneration of bicarbonate.
Normocytic or normochromic anemia is due to decreased production of erythropoietin.
The most common cause of bleeding is a qualitative defect in platelet function.
Infectious complications are common in CKD. Clinical findings include lymphopenia,
lymphoid tissue atrophy, decreased antibody production, and suppression of the
delayed hypersensitivity response.
The most common cardiovascular abnormality is hypertension, which is usually
present pre-ESRD and is aggravated by sodium retention and increased extracellular
fluid volume. Diabetes mellitus is an additional risk factor. Cardiac dysrhythmias may result from hyperkalemia, hypocalcemia, and decreased
coronary artery perfusion.
Respiratory changes include Kussmaul respiration, dyspnea from fluid overload,
pulmonary edema, uremic pleuritis (pleurisy), pleural effusion, and a predisposition to
Neurologic changes are due to increased nitrogenous waste products, electrolyte
imbalances, metabolic acidosis, axonal atrophy, and demyelination. Depression of the
CNS results in lethargy, apathy, decreased ability to concentrate, fatigue, irritability,
and altered mental ability.
Peripheral neuropathy may result in restless legs syndrome, paresthesias, bilateral
footdrop, muscular weakness and atrophy, and loss of deep tendon reflexes.
The treatment for neurologic problems is dialysis or transplantation. Altered mental
status is often the signal that dialysis must be initiated.
Renal osteodystrophy is a syndrome of skeletal changes that is a result of alterations
in calcium and phosphate metabolism. Osteomalacia is demineralization resulting
from slow bone turnover and defective mineralization of newly formed bone. Osteitis
fibrosa cystica results from decalcification of the bone and replacement of bone tissue
with fibrous tissue.
Pruritus results from a combination of the dry skin, calcium-phosphate deposition in
the skin, and sensory neuropathy.
Both sexes experience infertility and a decreased libido. Sexual dysfunction may also
be caused by anemia, peripheral neuropathy, and psychologic problems, physical
stress, and side effects of drugs.
Personality and beh