Uremia, which literally means urea in the blood is an excessive amount of metabolism waste products that should be excreted in urine accumulating in the blood. It is a syndrome associated with electrolyte, fluid, and hormone imbalances and other metabolic abnormalities that usually develop in conjunction with renal failure.
Definition & Facts
Uremia often develops with chronic kidney disease (CKD) and may be defined as an excessive amount of protein and amino acid metabolism waste products like creatinine and urea in the blood that are typically excreted in urine.
Uremia is the result of insufficient function of the kidneys and is usually present as a result of renal failure or along with chronic kidney disease. This syndrome is a complication of acute kidney failure and chronic kidney disease that occurs when waste products like urea build up in the body as the kidneys cannot eliminate them efficiently.
These waste products can become toxic to the body when they reach high levels. Uremia can affect any part of the body with symptoms ranging from vomiting and nausea to cardiovascular disease, seizures, and unexplained weight loss.
Symptoms & Complaints
The classic signs of the clinical syndrome include extreme fatigue, progressive weakness, loss of appetite with vomiting and nausea, muscle loss, tremors, frequent shallow respiration, and poor mental function.
Without intervention, the syndrome will worsen and lead to coma, stupor, and eventually death. As uremia is usually due to kidney failure, the symptoms often occur with signs of kidney failure. Patients may report itching, dry skin with uremic frost (or excretion of urea through the skin that leaves a whitish deposit), hypertension, coronary artery disease, anemia, anorexia, restless legs syndrome, muscle cramps, headaches, confusion, impotence, and increased sensitivity to infectious diseases.
Some people with uremia report non-specific symptoms that become chronic and progressively worse over time. Because symptoms are often non-specific, it can be difficult to diagnose the condition in young children. In severe cases, uremia patients can develop spontaneous bleeding that may include increasing bleeding from an underlying disorder, trauma, or gastrointestinal bleeding. Low electrolyte levels can also cause cardiac arrest.
Uremia can occur once creatine levels fall below 10-20 mL/min. Uremic syndrome is the result of chronic kidney disease or acute renal failure in which the kidneys are no longer able to eliminate waste products, allowing them to build up in the blood.
Patients with poorly controlled diabetes mellitus and/or high blood pressure are at an increased risk of developing kidney disease and renal failure, both of which may lead to uremia. Other risk factors in the development of kidney disease include smoking, alcohol use disorder, and being over the age of 60.
Patients who have kidney disease and fail to control it through regular exercise and a diet low in protein, potassium, and salt may develop uremia if their kidney disease worsens.
Uremia can be caused by decreased blood flow to the kidneys (which may be the result of dehydration, low blood pressure (hypotension), or congestive heart failure). Uremia can also be caused by acute injury and chronic kidney failure, tubular necrosis, and other kidney diseases.
Diagnosis & Tests
An accurate physical examination and medical history are important in determining whether uremia is chronic or acute. Causes may be identified in the case of acute uremia for a higher chance of recovering normal renal function. A physical exam will check for signs of the condition, such as pallor which is a very pale appearance.
The primary test for diagnosing uremia is a basic metabolic panel with phosphorus and serum calcium to evaluate a patient's blood urea nitrogen, creatinine, CFR, potassium, calcium, sodium, and phosphate levels. Uremia presents as elevated levels of creatinine and urea. Calcium levels are usually low and phosphate and potassium levels are usually elevated.
A diagnostic exam will also evaluate thyroid and parathyroid functions and check for anemia. A 24-hour urine test can be used as an alternative to check creatinine levels, but this test is not very accurate. The most reliable test is a radioisotope test to determine GFR (glomerular filtration rate). Accurate diagnosis is important to rule out similar conditions such as anemia and diabetic nephropathy.
Treatment & Therapy
If treated quickly, uremia can be reversible. If it is not treated soon, permanent damage to the kidneys can occur and kidney failure may result. Treating uremia usually requires hospitalization and begins with treating the injury to the kidney to prevent nitrogen waste from building up in the blood. The primary treatment for uremia is kidney dialysis that can relieve the symptoms and artificially remove waste products from the blood until normal kidney function is restored.
In some cases, hydration therapy, blood pressure medication, and/or blood transfusion may be necessary. Ongoing treatment could include dietary changes, and ongoing dialysis after the acute symptoms of uremia are addressed. A low-protein diet may help alleviate some symptoms of the condition and it may be recommended for people with mild to moderate renal failure.
Prevention & Prophylaxis
Preventing and managing kidney disease is the only effective way to avoid uremia. Patients who aggressively manage high blood pressure and diabetes with exercise, diet, and prescription medications may be able to prevent kidney failure completely and retain as much kidney function as possible. Hypertension and diabetes dramatically increase the risk of developing kidney disease and reducing the risk factors for those conditions.