Chronic kidney disease: signs, tests and everyday management

Chronic kidney disease (CKD) is a long-term condition in which the kidneys do not work as well as they should. This article explains who is at risk, how it is found, how it is managed and when to seek help, using information from the US National Institute of Diabetes and Digestive and Kidney Diseases, MedlinePlus, the US CDC and the NHS.

1. Introduction

The kidneys filter waste and extra fluid out of the blood. In CKD, the kidneys are damaged or have a structural problem, so waste and fluid can build up ^[1]. The damage usually happens slowly over months or years, although a sudden event can sometimes start it ^{[1, 2]}. The NIDDK notes that advanced, long-lasting CKD typically cannot be reversed, and in some people it leads to kidney failure ^[1]. The CDC adds that not everyone with kidney disease reaches kidney failure, and that treatment can slow its progress ^[3].

CKD is common. The CDC estimates that more than 1 in 7 adults in the United States has it, and that most do not know ^[3]. The NHS also describes it as common, more so with older age and in people of black or South Asian origin ^[4].

2. Causes and risk factors

Diabetes and high blood pressure are the two most common causes and account for most cases ^[2]. The NHS lists several other conditions that strain the kidneys, often in combination ^[4]:

• High cholesterol and kidney infections
• Glomerulonephritis, which is inflammation of the kidneys
• Autosomal dominant polycystic kidney disease, an inherited condition
• Blockages to urine flow, such as repeated kidney stones or an enlarged prostate
• Long-term regular use of certain medicines, including lithium and a group of painkillers called NSAIDs

MedlinePlus adds autoimmune disorders such as lupus, some toxic chemicals and urine flowing backward into the kidneys ^[2]. The NIDDK lists heart and blood vessel disease, a family history of kidney disease and older age as risk factors, and says the longer someone has diabetes or high blood pressure, the higher the risk ^[1].

3. Signs and symptoms

Most people with early CKD feel well. The NIDDK says many have no symptoms until the disease is advanced, and for many people blood and urine tests are the only way to detect it ^[1]. When the disease is more advanced, the NIDDK lists loss of appetite, nausea, tiredness or sleep problems, trouble concentrating, changes in how often you pass urine, foamy urine, itching, muscle cramps and swelling of the legs, feet or ankles ^[1]. The NHS also lists shortness of breath and blood in the urine ^[4]. These signs are not specific to CKD, so a doctor needs to look for the cause.

4. Diagnosis and tests

Blood and urine tests are the main way to confirm CKD. The CDC explains that the blood test measures a waste product called creatinine and the urine test checks for protein ^[3]. A urinalysis can show protein or other changes sometimes months or years before symptoms appear ^[2]. Depending on the case, a doctor may also arrange scans such as an ultrasound, or a kidney biopsy, to find the cause ^[2]. The NHS says test results are used to give the disease a stage, where a higher number means more serious CKD, and that people at higher risk, for example with diabetes or high blood pressure, may be advised to have regular testing ^[4].

5. Treatment and management

The NHS states that there is no way to make CKD disappear, but treatment can relieve symptoms and slow progression ^[4]. Your doctor decides what is right for you. Approaches described by the sources include:

• Treating the cause. Managing diabetes and high blood pressure can help slow progression ^[1]. MedlinePlus says blood pressure control slows further damage and that certain blood pressure medicines are often used, with a personal target set by your provider ^[2].
• Lifestyle changes. These include not smoking, regular exercise after checking with a provider, and limiting salt ^[2].
• Eating plan. The CDC advises working with a dietitian on a kidney-healthy plan ^[3]. MedlinePlus says this may mean limiting fluids, protein, phosphorus or potassium in some people ^[2].
• Treating complications. CKD can cause anaemia (a low red blood cell count), mineral and bone problems and a higher chance of heart disease ^{[1, 2]}.
• Vaccines. MedlinePlus lists hepatitis A and B, flu, pneumococcal and COVID-19 vaccines as part of care ^[2].
• Dialysis or transplant. In advanced disease these may be needed. MedlinePlus says dialysis is typically considered when about 10 to 15 percent of kidney function remains, and doctors discuss it in advance ^[2].

Always check with your provider before taking over-the-counter medicines, vitamins, herbs or supplements, and make sure every provider knows you have CKD ^[2]. The CDC also recommends including a nephrologist, a kidney doctor, on your care team ^[3].

6. Prevention and self-care

The CDC and NIDDK suggest these steps to protect the kidneys ^{[1, 3]}:

• Keep blood pressure at the target your doctor sets and keep blood sugar in range if you have diabetes.
• Stay physically active and aim for a healthy weight.
• Eat a healthy diet.
• Stop smoking.
• Avoid medicines that can injure the kidneys, and take prescribed medicines as directed.
• Get tested if you are at risk, and encourage at-risk relatives to be tested.

7. Special groups

The NIDDK notes that CKD is less common in children ^[1]. It also says some groups have higher rates of advanced kidney disease, possibly linked to higher rates of diabetes and high blood pressure ^[1]. CKD can also bring stress and depression, and the NIDDK advises talking with a health professional about coping ^[1].

8. When to see a doctor

See a doctor if you are at risk and have never had a kidney test. Also see a doctor for tiredness, swelling, foamy or bloody urine or changes in passing urine that do not go away ^{[1, 4]}. If you already have CKD, tell your doctor if symptoms worsen, such as chest pain, shortness of breath or worsening swelling ^[1].

In an emergency, call your local emergency number (112 in India, 911 in the United States).

9. Conclusion

CKD often develops quietly, so testing is the key to finding it early. Controlling blood pressure and blood sugar, avoiding smoking, eating well and following your care team's advice can slow its progress and protect the heart. Your doctor will decide which tests and treatments suit you.