Chronic kidney disease (CKD) is a progressive condition where the kidneys gradually lose their ability to filter waste, excess fluids, and toxins from the blood. As kidney function declines over months or years, a wide range of complications can develop, affecting many organs and systems in the body. These complications arise because the kidneys play crucial roles beyond just filtering blood—they regulate blood pressure, balance minerals and electrolytes, produce hormones, and maintain acid-base balance. When these functions are impaired, the consequences can be serious and multifaceted.
One of the most common complications of CKD is **high blood pressure (hypertension)**. The kidneys help regulate blood pressure by controlling fluid balance and releasing hormones that constrict or dilate blood vessels. When kidney function deteriorates, this regulation falters, often causing or worsening hypertension. High blood pressure, in turn, accelerates kidney damage, creating a vicious cycle. It also increases the risk of heart disease and stroke, which are leading causes of death in people with CKD.
Another major complication is **anemia**, a condition characterized by a low number of red blood cells or hemoglobin. Healthy kidneys produce erythropoietin, a hormone that signals the bone marrow to make red blood cells. In CKD, reduced erythropoietin production leads to fewer red blood cells, causing fatigue, weakness, and shortness of breath. Anemia also contributes to heart strain and worsens overall quality of life.
**Bone disease and mineral imbalances** are also frequent in CKD. The kidneys regulate calcium and phosphate levels and activate vitamin D, which is essential for bone health. When kidney function declines, phosphate builds up in the blood, calcium levels drop, and vitamin D activation decreases. This imbalance causes bones to become weak, brittle, and prone to fractures—a condition known as renal osteodystrophy. Patients may experience bone pain and deformities.
**Fluid retention and swelling (edema)** occur because failing kidneys cannot remove excess water and salt efficiently. This leads to swelling in the legs, ankles, feet, and sometimes the face or hands. Fluid overload can also cause high blood pressure and strain the heart, potentially leading to congestive heart failure.
**Electrolyte disturbances** are common and can be dangerous. For example, potassium levels often rise (hyperkalemia) because the kidneys cannot excrete potassium properly. High potassium can cause life-threatening heart rhythm abnormalities. Other imbalances include low calcium, high phosphate, and acid-base disturbances (metabolic acidosis), which can cause muscle weakness, breathing difficulties, and worsen bone disease.
**Nerve damage (neuropathy)** is another complication. Toxins that accumulate due to poor kidney filtration can damage nerves, leading to symptoms like numbness, tingling, burning sensations, or weakness, especially in the hands and feet. This can affect mobility and quality of life.
**Cardiovascular disease** is the leading cause of death in CKD patients. Besides hypertension, CKD causes changes in blood vessels and the heart muscle, increasing the risk of heart attacks, heart failure, and strokes. The buildup of waste products and inflammation contributes to atherosclerosis (hardening of arteries).
**Gastrointestinal symptoms** such as nausea, vomiting, loss of appetite, and weight loss often appear in advanced CKD. These symptoms result from toxin buildup and metabolic imbalances, making nutrition challenging and further weakening the patient.
**Skin problems** like persistent itching (pruritus) and dryness are common due to waste accumulation and mineral imbalances. Skin may also show changes such as dryness, discoloration, or nail abnormalities.
**Sleep disturbances** including restless legs syndrome and insomnia are frequently reported. These may be linked to nerve damage, anemia, and metabolic changes.
In advanced stages, **uremic syndrome** can develop, where high levels of waste products in the blood cause widespread symptoms including confusion, difficulty concentrating, seizure
