Chronic kidney disease (CKD) is a health condition that involves reduced function of the kidneys. There are various causes of reduced kidney function and the severity of the condition can vary greatly.
It is estimated that approximately 10% of all individuals have some degree of chronic kidney disease. It can develop at any individual of any age, but is more common among the elderly and females.
Signs and Symptoms
Initially, there are few noticeable symptoms of reduced kidney function because the body naturally has greater kidney function than is required. However, as chronic kidney disease progresses and the renal function continues to decline, several symptoms may become evident. These may include:
- Urination changes: frequent urination at night, painful urination, cloudy or foamy urine appearance
- Peripheral edema: swelling in the hands and feet due to reduced excretion of bodily fluids
- Fatigue: feeling tired due to anemia for reduced production of erythropoietin (EPO) in the kidneys
- Itchy skin: waste products build up in the blood and can cause significant itching
- Loss of appetite and weight: accumulation of waste products in the blood can cause loss of appetite, nausea and vomiting and lead to weight loss
- Dyspnea: shortness of breath due to associated anemia or fluid build-up in the lungs
- Dizziness: linked to reduced supply of oxygen to the brain
Chronic kidney disease is usually diagnosed with a simple blood test to estimate the volume of blood that is filtered by the kidneys in a given time.
The estimate glomerular filtration rate (eGFR) can be calculated from the concentration of creatinine in a blood sample to estimate the volume of blood that is filtered through the glomeruli in the kidneys per minute. A healthy person typically has an eGFR greater than 90 mL/min and less than this begins to indicate impaired kidney function.
There are five stages of chronic kidney disease, categorized as follows:
- Stage 1 (G1): normal eGFR (>90 mL/min) with evidence of kidney damage from other tests.
- Stage 2 (G2): slightly decreased eGFR (60-89).
- Stage 3a (G3a): mildly decreased eGFR (45-59) with mild to moderate decrease in kidney function.
- Stage 3b (G3b): moderately decreased eGFR (30-44) with moderate to severe reduction in kidney function.
- Stage 4 (G4): severely decreased eGFR (15-29) with severe reduction in kidney function and possible symptoms evident.
- Stage 5 (G5): severely decreased eGFR (<15) and referred to as renal failure.
As it is normal for the eGFR to very slightly over time, it is necessary to take several measurements at different times to confirm a diagnosis of chronic kidney disease.
A general practitioner can treat most cases of chronic kidney disease in the early stages of disease without referral to a specialist. However, referral to a specialist is often beneficial for patient with stage 4 or stage 5 CKD.
Initially, it is important to identify and address any underlying conditions that may be causing the function of the kidneys to worsen. Specifically, diabetes and hypertension are common causes of the disease and lifestyle modifications or medications can be beneficial to manage these factors.
The next phase of treatment is to prevent or slow the progression of disease. It is important to avoid use of medications that are linked to worsening of kidney function, such as non-steroidal anti-inflammatory drugs (NSAIDs). Additionally, ensuring weight and blood pressure is in the normal range is also beneficial.
Patients with CKD are more likely to be affected by cardiovascular disease (CVD) and, therefore, it is worthwhile to prevent related complications if possible. This includes lifestyle modifications such as adopting a healthy diet and exercise habits, in addition to appropriate medications, if required.