ureemia

Uremia is a clinical syndrome that results from severe kidney dysfunction, in which the kidneys are no longer able to adequately clear waste products from the blood. It reflects the accumulation of uremic toxins and disturbances in fluid, electrolyte, and acid-base balance caused by reduced glomerular filtration rate (GFR).

Causes and pathophysiology: Uremia most commonly occurs in the setting of advanced chronic kidney disease or after acute kidney injury requiring dialysis. When GFR falls below approximately 15 ml/min, retention of nitrogenous wastes such as urea and creatinine, along with middle-molecule and protein-bound toxins, as well as disturbances in phosphate, potassium, calcium, and acid-base balance, contribute to systemic symptoms.

Clinical features: Uremia presents with fatigue, anorexia, nausea, vomiting, and weight loss. Cognitive changes, irritability, pruritus, and sleep disturbances are common. In advanced disease, patients may develop pericarditis, neuropathy, encephalopathy, edema, and severe hypertension or fluid overload.

Diagnosis and differential: Laboratory findings include elevated blood urea nitrogen and creatinine, metabolic acidosis, and electrolyte abnormalities (notably hyperkalemia and hyperphosphatemia with hypocalcemia). The syndrome is distinguished from azotemia by its broader systemic manifestations and accompanying symptoms.

Management and prognosis: Renal replacement therapy is the cornerstone of treatment, via long-term dialysis (hemodialysis or peritoneal dialysis) or kidney transplantation. In eligible patients, transplantation offers potential cure. Non-dialysis management focuses on symptom control and slowing progression through dietary modifications, phosphate binders, iron and erythropoiesis-stimulating agents for anemia, bicarbonate therapy for acidosis, and control of blood pressure and comorbid conditions. Emergent dialysis is indicated for life-threatening complications such as refractory acidosis, severe hyperkalemia, pulmonary edema, or uremic encephalopathy. Without dialysis, uremia is life-threatening; dialysis and transplantation improve survival but do not restore normal kidney function.