CHRONIC KIDNEY DISEASE
Chronic kidney disease (CKD) is the progressive and irreversible destruction of the kidneys. The kidneys are essential parts of your body.
They have several functions, including:
- Helping maintain the balance of minerals and electrolytes in your bodies, such as calcium, sodium, and potassium.
- Playing an essential role in the production of red blood cells.
- Maintaining the delicate acid-base balance of your blood.
- Excreting water-soluble wastes from your body.
Causes of Chronic Kidney Disease
The most common causes of CKD are high blood pressure and diabetes.
Each kidney contains about 1 million tiny filtering units called nephrons.
Any disease that injures or scars these filtering units can cause kidney disease.
Diabetes and high blood pressure can both damage your nephrons.
High blood pressure can also damage the blood vessels of your kidneys, heart, and brain.
This is key because blood vessel diseases are generally dangerous to your kidneys.
The kidneys are highly vascularized, meaning they contain lots of blood vessels.
Autoimmune diseases such as lupus can damage blood vessels and can make antibodies against kidney tissue.
There are various other causes of CKD. Polycystic kidney disease is a hereditary cause of CKD.
Glomerulonephritis can be due to lupus.
It can also appear after a streptococcal infection.
The risk of CKD increases for those over the age of 65. It runs in families.
It’s more likely to occur in African-Americans, Native Americans, and Asian-Americans.
Other risk factors for CKD include:
- cigarette smoking
- high cholesterol
- diabetes (types 1 and 2)
- autoimmune disease
- obstructive kidney disease, including bladder obstruction caused by benign prostatic hyperplasia (BPH)
- cirrhosis and liver failure
- narrowing of the artery that supplies your kidney
- kidney cancer
- bladder cancer
- kidney stones
- kidney infection
- the systemic lupus erythematosus (SLE)
- vesicoureteral reflux, which occurs when urine flows back into your kidney
Symptoms of Chronic Kidney Disease
CKD doesn’t cause any symptoms until most of your kidney is destroyed.
Once the kidney is severely damaged, the symptoms of CKD can include:
- swelling around your eyes, which is called periorbital edema
- swelling of your legs, which is called pedal edema
- shortness of breath
- vomiting, especially in the morning and after eating
- a urine-like odor to your breath
- bone pain
- abnormally dark or light skin
- an ashen cast to your skin, which is called uremic frost
- mental cloudiness
- numbness in your hands and feet
- restless leg syndrome
- brittle hair and nails
- weight loss
- a loss of muscle mass
- muscle twitching and cramps
- easy bruising and bleeding
- blood in your stools
- excessive thirst
- low level of interest in sex, impotence
- sleep apnea
- You may also have the symptoms of any diseases that are contributing to your kidney problems
The diagnosis of CKD starts with a medical history. A family history of kidney failure can raise suspicions, as can a history of high blood pressure or diabetes. However, other tests are necessary to confirm that you have CKD.
Complete Blood Count (CBC)
A complete blood count (CBC) can show anemia. Your kidneys make erythropoietin, which is a hormone.
This hormone stimulates your bone marrow to make red blood cells.
When your kidney is severely damaged, your ability to make erythropoietin decreases.
This causes a decline in red blood cells known as anemia.
CKD can affect your electrolyte levels. Potassium may be high and bicarbonate levels may below if you have CKD.
There may also be an increased acid in the blood.
Blood Urea Nitrogen (BUN)
Blood urea nitrogen (BUN) can become elevated when your kidney starts to fail.
Normally, your kidney clears the products of protein breakdown from your blood.
However, after kidney damage, these byproducts build up.
Urea is one byproduct of protein breakdown.
Urea is what gives urine its odor.
As kidney function declines, your creatinine increases. This protein is also related to muscle mass.
Parathyroid Hormone (PTH)
The kidney and the parathyroid glands interact through the regulation of calcium and phosphorus.
A change in kidney function affects the release of PTH.
This affects calcium levels throughout your body.
When your kidney progresses to end-stage renal disease (ESRD), it no longer excretes enough phosphorus and it impairs vitamin D synthesis.
Your bones may release calcium.
This causes your bones to become weak over time.
Renal Flow and Scan
This is an imaging study of kidney function.
This noninvasive test provides images to help determine whether there’s an obstruction.
Additional tests for CKD include:
- a kidney biopsy
- a bone density test
- an abdominal CT scan
- an abdominal MRI
Treatment for Chronic Kidney Disease
CKD is chronic and irreversible.
Treatment focuses on improving the underlying disease.
Treatment can also prevent and manage complications of CKD, such as:
- fluid overload
- congestive heart failure
- brittle bones
- weight loss
- electrolyte imbalance
Control of underlying problems, such as hypertension and diabetes, can slow the progress of kidney damage.
Once your kidney function reduces to 10 percent or less, the symptoms become obvious. At this point, you may need dialysis or a kidney transplant.
ESRD occurs when your kidneys clearly begin to shut down.
The treatment for CKD and ESRD includes:
- quitting smoking if you smoke
- restricting fat in your diet
- restricting salt in your diet to control blood pressure and prevent fluid overload
- restricting protein in your diet (but still getting adequate calories to maintain your weight)
- restricting potassium in your diet
- getting adequate exercise
- getting dialysis to purify your blood
- getting a kidney transplant
- restricting your fluids to prevent fluid overload
- restricting carbohydrates if you have diabetes
- controlling diabetes if you have it
- controlling your blood pressure
- taking iron and vitamin supplements to manage anemia
- getting erythropoietin injections to stimulate the production of red blood cells
- taking calcium and vitamin D supplements
- taking phosphate binders
- taking stool softeners for constipation
- taking antihistamines for itching
You may be more susceptible to infection if you have CKD or ESRD. Doctors recommend that you get the following vaccinations:
- pneumococcal vaccine
- hepatitis B vaccine
- influenza vaccine
- H1N1 (swine flu) vaccine
Renal Replacement Therapy in chronic kidney disease
- Indications for renal replacement therapy in patients with chronic kidney disease (CKD) include the following:
- Severe metabolic acidosis
- Intractable volume overload
- Failure to thrive and malnutrition
- Peripheral neuropathy
- Intractable gastrointestinal symptoms
- In asymptomatic adult patients, a glomerular filtration rate (GFR) of 5-9 mL/min/1.73 m², irrespective of the cause of the CKD or the presence or absence of other comorbidities.
Timely planning for long-term renal replacement therapy for chronic kidney disease
Consider the following:
- Early patient education regarding natural disease progression, different dialytic modalities, renal transplantation, and option to refuse or discontinue chronic dialysis
- Timely elective peritoneal dialysis catheter insertion
- Timely referral for renal transplantation
- Protein restriction
- Protein restriction early in chronic kidney disease (CKD) as a means to delay a decline in the glomerular filtration rate (GFR) is controversial.
- However, as the patient approaches CKD stage 5, this strategy is recommended in adults (but not in children) to delay the onset of uremic symptoms.
- Patients with CKD who already are predisposed to becoming malnourished are at higher risk for malnutrition with overly aggressive protein restriction.
- Malnutrition is a well-established predictor of increased morbidity and mortality in the population with end-stage renal disease (ESRD) and must be avoided if possible.
- Salt restriction
- Reduction in salt intake may slow the progression of diabetic CKD, at least in part by lowering blood pressure.
- A meta-analysis found that dietary salt reduction significantly reduced blood pressure in type 1 and type 2 diabetes, with results comparable to those of single-drug therapy.
- This finding is consistent with other evidence relating salt intake to blood pressure and albuminuria in hypertensive and normotensive patients.
- The dietary sodium recommendation for the general population in public health guidelines is less than 5-6 g daily.
- Children and adults with tubulointerstitial diseases may experience salt wasting, and the salt restriction would not usually be required in that situation.
- Other dietary restrictions
The following dietary restrictions may also be indicated:
- Phosphate restriction starting early in CKD
- Potassium restriction
- Sodium and water restriction as needed to avoid volume overload
- Fruits and vegetables
A study by Goraya et al showed that increasing the amount of alkali-inducing fruits and vegetables in the diet may help to reduce kidney injury.
In this report, 30 days of a diet that included fruits and vegetables, in amounts calculated to reduce dietary acid by half, resulted in decreased urinary albumin, N-acetyl β-D-glucosaminidase, and transforming growth factor β in patients with moderately reduced estimated GFR as a result of hypertensive nephropathy.
Nutritional guidelines for chronic kidney disease
The National Kidney Foundation’s Kidney Disease Outcomes Quality Initiative (KDOQI) issued a clinical practice guideline for Nutrition in Chronic Renal Failure, as well as a 2008 revision of recommendations for Nutrition in Children with CKD.
For adult patients on maintenance dialysis, the KDOQI guidelines recommend routine assessment of the following nutritional parameters:
- Pre dialysis or stabilized serum albumin: Monthly
- Percentage of usual post-dialysis (hemodialysis) or post drain (peritoneal dialysis) body weight: Monthly
- Percentage of standard (National Health and Examination Survey II [NHANES II]) body weight: Every 4 months
- Subjective global assessment: Every 6 months
- Dietary interview and/or diet diary: Every 6 months
- Protein Equivalent of Total Nitrogen Appearance normalized to body weight. Monthly with hemodialysis; every 3-4 months with peritoneal dialysis.
- Consultations and Long-Term Monitoring
Consultations for the management of patients with chronic kidney disease (CKD) may include the following:
- Early nephrology referral (decreases morbidity and mortality)
- Renal dietitian
- Surgery for permanent vascular access or for peritoneal catheter placement
- Referral to the renal transplant center
- Patients with CKD should be referred to a nephrologist early in the course of their disease and have continued nephrologist follow-up until initiation of chronic renal replacement therapy, during dialysis, and after kidney transplantation.
- Moreover, a multidisciplinary approach to care, including involvement of the nephrologist, primary care physician, renal dietitian, nurse, and social worker, should be initiated early in the course of CKD, with close patient follow-up.
- How Can I Prevent Chronic Kidney Disease?
You can’t always prevent CKD. However, controlling conditions like high blood pressure and diabetes can help. You should get regular screenings for CKD if you’re at high risk. Getting an early diagnosis of CKD can help slow its progress.
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