CHAPTER 13. CHRONIC KIDNEY DISEASE
Michael J. Germain and Debra E. Heidrich
DEFINITIONS AND INCIDENCE
Chronic kidney disease (CKD) is defined as kidney damage or impaired renal function that persists for 3 or more months (National Kidney Foundation [NKF], 2002). The severity of the disease is staged based on the level of kidney function as measured by the glomerular filtration rate (GFR) (Table 13-1). In the United States, it is estimated that 80,000 people are diagnosed with CKD annually, 20 million people are living with this disease, and an additional 20 million people are at increased risk (Coresh, Astor, Greene et al., 2003; NKF, 2006; United States Renal Data System [USRDS], 2005). The incidence and prevalence of CKD in the United States have been rising steadily, likely due to the increased prevalence of obesity and type 2 diabetes and an increasingly elderly population.
Stage | Description | GFR (ml/min/1.73 m 2) |
---|---|---|
1 | Kidney damage with normal or increased GFR | ≥90 |
2 | Kidney damage with mild decrease in GFR | 60-89 |
3 | Moderate decrease in GFR | 30-59 |
4 | Severe decrease in GFR | 15-29 |
5 | Kidney failure | <15 or dialysis |
The most advanced stage of CKD is end-stage renal disease (ESRD). Patients with ESRD require dialysis or transplantation to survive (Zandi-Nejad & Brenner, 2005). In 2003, about 450,000 patients in the United States had ESRD, of whom 325,000 were being treated with dialysis and the remaining 128,000 received a kidney transplant (USRDS, 2005). There were 82,588 deaths attributed to ESRD in 2003, and about 13.5% of these patients were receiving care from a hospice at the time of their deaths (USRDS, 2005).
Risk factors for CKD include diabetes, hypertension, and family history of kidney disease. In addition, African Americans, Hispanics, Pacific Islanders, Native Americans, and people over the age of 65 are at increased risk (NKF, 2006). Cardiac disease is the single greatest cause of mortality in the ESRD population (USRDS, 2005). Older patients with ESRD and CHF have an annual mortality rate of about 60% and an expected survival of less than 6 months. This emphasizes the importance of palliative care and end-of-life planning for this group of patients (Germain & Cohen, 2001).
Patients with chronic renal failure have a high symptom burden. A study by Wiesbord, Fried, Arnold et al. (2005) showed that the median number of symptoms for patients with ESRD receiving chronic hemodialysis was nine, with the severity of each averaging 3 on a scale of 1 to 5. Dry skin, fatigue, itching, and bone and/or joint pain were reported by at least 50% of patients. The overall symptom burden and severity were each correlated directly with impaired quality of life and depression.
Increasing evidence accrued in the past decades indicates that the adverse outcomes of chronic kidney disease, such as kidney failure, cardiovascular disease, and premature death, can be prevented or delayed through early detection and initiation of interventions to slow progression. Methods to slow the progression of CKD include optimal control of hypertension, optimal management of diabetes and hyperlipidemia, avoidance of nephrotoxins, cessation of smoking, and the use of medications that block the production of or effect of angiotensin II (Shaver, 2004).
ETIOLOGY AND PATHOPHYSIOLOGY
The two main causes of chronic kidney disease are diabetes (43%) and hypertension (26%). Other conditions that affect the kidneys are glomerulonephritis, inherited diseases (e.g., polycystic kidney disease), interstitial nephritis and/or pyelonephritis, and secondary glomerulonephritis (e.g., lupus nephritis) (Shaver, 2004). Obstructions due to kidney stones, tumors, or an enlarged prostate gland in men also can lead to kidney damage.
Each human kidney contains about 1 million nephrons, consisting of the renal corpuscle (glomerulus) and renal tubules, that function to maintain homeostatic functions of the body (Kumar, 2004) (Table 13-2). Insult to the kidney causes acute inflammation of glomeruli leading to a cascade of proteinuria, glomerular sclerosis, interstitial fibrosis, and, eventually, permanent nephron damage. In response to a reduction in renal function, the remaining nephrons adapt with hyperfiltration. For this reason, patients can lose up to 75% of GFR with no pronounced symptoms (Shaver, 2004). The hyperfiltration causes glomerular capillary hypertension, which leads to glomerular sclerosis and nephron death. The glomerular capillary hypertension is maintained by the renin-angiotensin-aldosterone system (Zandi-Nejad & Brenner, 2005). The kidneys lose their ability to concentrate urine adequately, putting patients at risk for dehydration. As the GFR further declines, the body is unable to rid itself of excess water, salt, and other waste products, and serum urea nitrogen and creatinine levels increase (Molzahn, 2005a). The process of nephron death, hyperfiltration, and additional nephron death means that CKD tends to be progressive. This progression, however, may be slowed with optimal management.
Function | Mechanism | Affected Elements |
---|---|---|
Waste excretion | Glomerular filtration | Urea, creatinine |
Tubular secretion | Urate, lactate, drugs (diuretics) | |
Tubular catabolism | ||
Electrolyte balance | Tubular NaCl absorption | Volume status, osmolar balance |
Tubular K + secretion | Potassium concentration | |
Tubular H + secretion | Acid-base balance | |
Tubular water absorption | Osmolar balance | |
Tubular calcium, phosphate, magnesium transport | Calcium, phosphate, magnesium homeostasis | |
Hormonal regulation | Erythropoietin production | Red blood cell mass |
Vitamin D activation | Calcium homeostasis | |
Blood pressure regulation | Altered sodium excretion | Extracellular volume |
Renin production | Vascular resistance | |
Glucose homeostasis | Gluconeogenesis | Glucose supply (maintained) in prolonged starvation |
CKD is a common microvascular complication of diabetes. Microangiopathy affecting the afferent and efferent arterioles of the nephron causes glomerulosclerosis. This leads to scarring of the glomerulus, tubules, and interstitium of the kidney and an increase in intraglomerular pressure. Microalbuminuria occurring about 10 to 15 years after the diagnosis of diabetes (preclinical diabetic nephropathy) is an early marker of developing diabetic nephropathy. With progression of the disease, more and more protein is excreted in the urine and renal insufficiency ensues (Barnett & Braunstein, 2004; Molzahn, 2005b).
A sustained systemic high blood pressure leads to nephrosclerosis. There is a direct correlation between the duration and degree of hypertension and the severity of renal damage. Kidney disease can also lead to hypertension. For example, hypertension may result from the kidney’s decreasing ability to excrete salt and water when glomeruli are damaged (Molzahn, 2005b). Thus, a vicious cycle occurs as the renal damage causes hypertension and hypertension worsens renal damage.
ASSOCIATED SYMPTOMS
Many people have no symptoms of declining renal function until their kidney disease is advanced, that is, stage 4 or 5. Uremia affects every organ system and is likely due to multiple factors, including retained molecules, deficiencies of important hormones, and metabolic factors (Shaver, 2004). Table 13-3 shows the major manifestations of uremia.
System | Manifestations |
---|---|
Nervous | Central |
Irritability | |
Insomnia | |
Lethargy | |
Anorexia | |
Seizures | |
Coma | |
Peripheral | |
Glove and stocking sensory loss | |
Restless leg | |
Footdrop or wrist drop | |
Musculoskeletal | Muscle weakness |
Gout and pseudogout | |
Renal osteodystrophy | |
Hematologic | Anemia |
Bleeding disorders | |
Leukocyte dysfunction | |
Gastrointestinal | Anorexia |
Nausea | |
Vomiting | |
Disturbance of taste | |
Gastritis | |
Peptic ulcer | |
Gastrointestinal bleeding | |
Cardiovascular | Cardiomyopathy |
Arrhythmias | |
Pericarditis | |
Accelerated atherosclerosis | |
Pulmonary | Noncardiogenic pulmonary edema |
Pneumonitis | |
Pleuritis | |
Acid-base/electrolytes | Anion gap acidosis |
Hyperkalemia | |
Fluid overload | |
Hypocalcemia | |
Hyperphosphatemia | |
Hypermagnesemia | |
Endocrine/metabolism | Hyperparathyroidism |
Increased insulin resistance | |
Amenorrhea | |
Impotence | |
Hyperlipidemia | |
Skin | Pruritus |
Yellow pigmentation |
HISTORY AND PHYSICAL EXAMINATION
History includes identification of those patients at high risk for CKD, including patients with any family history of CKD and those with diabetes, hypertension, recurrent urinary tract infections, urinary obstruction, or a systemic illness that affects the kidneys (Snyder & Pendergraph, 2005). The history should also include the onset of any of these high-risk diseases, the treatments used to manage the disease over time, and the effectiveness of these treatments.
Patients with a diagnosis of renal disease may present in various ways. In addition to the signs and symptoms of uremia as presented in Table 13-3, physical findings that might suggest the presence of renal disease include the following:
▪ Skin: itching from uremia with related excoriations
▪ Eyes: optic fundi changes or alterations (severe hypertension)
▪ Ears: hearing loss (associated with hereditary nephritis)
▪ Chest: pericardial rub (pericarditis); diminished lung sounds (pleural effusion) or rales (congestive heart failure)
▪ Urinary: enlarged kidneys (polycystic kidney disease); flank pain; enlarged bladder (bladder outlet obstruction)
▪ Peripheral vascular: peripheral edema; anasarca
▪ Musculoskeletal: joint pain; arthritis; bone pain; muscle weakness
▪ Mental status: changes in cognition; asterixis
DIAGNOSTICS
Several diagnostic tests may be required to identify the cause of CKD and to monitor the progression of the disease over time. The following may provide valuable information (Veterans Hospital Administration/Department of Defense [VHA/DoD], 2001):
▪ Urinalysis
▪ Quantitative proteinuria
▪ Complete blood count
▪ Na +, K +, Cl −, CO 2, blood urea nitrogen, serum creatinine, glucose, Ca 2+, PO 4−, albumin, total protein
▪ Estimated GFR
▪ Cholesterol
▪ Kidney ultrasound
To evaluate for urinary tract obstruction
To estimate the size of the kidney
To evaluate for polycystic kidney disease
The following laboratory data may be helpful to identify complications in stages 3 and 4 CKD (Snyder & Pendergraph, 2005):
▪ Hemoglobin to identify anemia
▪ Red blood cell indexes, reticulocyte count, iron studies, and fecal occult blood test to rule out other causes of anemia
▪ Serum electrolytes to identify hyperkalemia, hyponatremia, and acidosis
▪ Calcium, phosphorus, and parathyroid hormone levels to identify hypocalcemia, hyperphosphatemia, and secondary hyperparathyroidism
▪ Serum albumin and total protein levels to identify hypoalbuminemia and decreased levels of immunoglobulins in patients with nephritic levels of proteinuria or signs of malnutrition
INTERVENTIONS
When CKD is diagnosed, it is important for the patient and family to understand the illness and its management, taking into account the nature of the disease in the context of patient and family values and wishes. Aggressive management of CKD involves using interventions to slow or arrest disease progression. As mentioned earlier, these interventions include optimal control of hypertension, optimal management of diabetes and hyperlipidemia, avoidance of nephrotoxins, cessation of smoking, and the use of medications that block the production of or effect of angiotensin II. Angiotensin-converting enzyme inhibitors and angiotensin II receptor blockers lower blood pressure and demonstrate a nephroprotective effect beyond that of their ability to lower blood pressure (Shaver, 2004). Restricting dietary protein may slow CKD progression, but protein malnutrition must be avoided.
Renal impairment affects medication selection and dose. Nephrotoxic drugs should be avoided, and medications eliminated via the urine may require dose reduction. Table 13-4 lists dosage modifications for selected medications when used in patients with renal failure.
NSAIDs, Nonsteroidal anti-inflammatory drugs. | ||
*Due to the potential for accumulation of active metabolites, dosage reduction or opioid rotation may be required over time. |
||
Data from Neely, K.J. & Roxe, D.M. (2000). Palliative care/hospice and the withdrawal of dialysis. Journal of Palliative Medicine, 3(1), 57-67; and Shaver, M.J. (2004). Chronic renal failure. In T.E. Andreoli, C.C. Carpenter, R.C. Griggs, et al. (Eds.). Cecil essentials of medicine (6th ed., pp.301-310). Philadelphia: Saunders. | ||
Major Dosage Reduction | Minor or No Dosage Reduction | Avoid Usage |
---|---|---|
Antibiotics
Aminoglycosides
Penicillin
Cephalosporins
Sulfonamides
Vancomycin
Quinolones
Fluconazole
Acyclovir/ganciclovir
Foscarnet
Imipenem
Others
Digoxin
Procainamide
H 2 antagonists
Metoclopramide
Meperidine
Codeine
Propoxyphene
|
Antibiotics
Erythromycin
Nafcillin
Clindamycin
Chloramphenicol
Isoniazid/rifampin
Amphotericin B
Aztreonam/tazobactam
Doxycycline
Others
Antihypertensives
Benzodiazepines
Diphenhydramine
Haloperidol
Prochlorperazine
Phenytoin
Lidocaine
Quinidine
Spironolactone
Triamterene
Opioids*
|
Antibiotics
Nitrofurantoin
Nalidixic acid
Tetracycline
Others
NSAIDs
Aspirin
Sulfonylureas
Lithium carbonate
Acetazolamide
|
Patients with ESRD require kidney replacement therapy to survive, either some form of dialysis (home peritoneal dialysis, home hemodialysis, in-center hemodialysis) or a renal transplantation. Hemodialysis is associated with significant symptom burden, leading some patients, especially the elderly and those with multiple comorbid medical conditions, to decline dialysis. Those who decide to forgo dialysis should be referred to a hospice program and receive maximal palliative care (Moss, 2001).
Offering the patient a trial of dialysis for 3 to 6 months may be an acceptable choice for those with a limited prognosis (Cohen, Germain, & Poppel, 2003).
Over time, some patients who are on dialysis may elect to stop treatment. Often, this decision is due to (1) failure to thrive despite aggressive intervention, (2) poor quality of life as defined by the patient, or (3) worsening of comorbid complications (amputations, calciphylaxis, stroke, CHF), terminal illness (malignancies, AIDS, etc), or acute catastrophic illness. Death after dialysis withdrawal usually occurs quickly. Studies of patients who withdrew from dialysis showed that the time to death after stopping dialysis was less than 30 days, with a median of 8 to 10 days (Cohen, McCue, Germain et al., 1995; Neely & Roxe, 2000). The presumed immediate cause of death in most of these patients was uremia, which is often described as a painless and peaceful death. However, patients who stop dialysis are at high risk for delirium and accumulation of toxic metabolites of certain medications; these symptoms should be anticipated and appropriately managed. Box 13-1 provides a helpful checklist to use when patients elect to withhold or withdraw from dialysis.
Box 13-1
1. Identify patient who may benefit from withdrawal.
a. Estimate prognosis; share with patient and family.
b. Poor quality of life
c. Pain unresponsive to treatment
d. Progressive untreatable disease (e.g., cancer, dementia, AIDS, peripheral vascular disease, CHF)
e. Unable or unwilling to tolerate further dialysis
2. Discuss goals of care with patient and family and review advanced care planning/advanced directives.
3. Ask patient/family if they are satisfied with quality of life on dialysis.
4. Discuss possible treatable symptoms and their palliation.
a. Rule out depression.
b. Assess for secondary gain by family.
5. Make explicit that dialysis withdrawal is an option.
6. Reassure that dialysis withdrawal can be a peaceful death.
7. Allow time for discussion.
8. Let the patient and family know the decision is reversible at any time.
9. Once the decision has been made to withdraw from dialysis, outline a plan with the patient and family.
10. Offer options of spiritual/religious support.
11. Discuss location at which patient will be most comfortable in last few days (home, hospice, nursing home, hospital).
12. Stop nonpalliative medications and order palliative medications.
13. Make hospice referral.
14. Reinforce continued availability of clinician.
15. Arrange bereavement services.
Symptom relief should be a priority for all patients throughout the course of treatment for CKD. Table 13-5 lists medications that may be helpful for common CKD-related symptoms.
Symptom | Treatment | Dosage | Comments |
---|---|---|---|
Cramps | Quinine | 260-325 mg oral | Limit to three doses daily |
Vitamin E | 400 IU oral | ||
Carnitine | 1000-2000 mg IV during dialysis | Also used for cardiomyopathy and refractory anemia | |
Restless legs | Clonazepam | 0.5-2 mg oral at bedtime as needed | |
Carbidopa-levodopa | 25-100 mg oral at bedtime as needed | ||
Pergolide | 0.05 mg oral daily up to 0.2 mg oral four times daily | ||
Bromocriptin | 2-20 mg oral at bedtime | ||
Gabapentin | 100 mg every other day up to 300 mg three times daily | ||
Clonidine | 0.1-1.0 mg oral at bedtime | ||
Pruritus | Skin moisturizer | ||
Hydrourea cream | |||
UVB light | |||
H 1 antagonist (any) | |||
Activated charcoal | 6 g oral four times daily × 8 wk | ||
Lidocaine | 100 mg IV during dialysis | Potential for seizure | |
Ondansetron | 4 mg oral twice daily | Expensive | |
Plasmapheresis | 3-4 exchanges | ||
Hypotension (intradialytic or persistent) | Alterations to dialysis bath, temperature, sodium, or ultrafiltration | ||
Midodrine | 2.5-10 mg oral three times daily as needed or predialysis | ||
Sertraline | 25-50 mg oral predialysis | ||
Ketotifen | 100 mg IV on dialysis | Mast cell stabilizer, not available in the United States | |
Fatigue | Methylphenidate | 5-10 mg oral AM and noon |
CONCLUSION
CKD is an increasingly common disorder in the United States. Although the progression of this disease can be slowed by early intervention, CKD is often diagnosed at a late stage because signs and symptoms do not become evident until significant kidney damage occurs. Cardiovascular disease is a common complication of CKD and is associated with a high mortality. Patients with ESRD require kidney replacement therapy with either dialysis or a kidney transplant to survive. Patients with CKD experience a high symptom burden throughout the continuum of care and require aggressive palliative symptom management to promote comfort and enhance quality of living.
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