Uremia

What uremia is

When kidney function falls to roughly 10 to 15% of normal or less, the kidneys cannot remove waste products from protein breakdown (including urea), excess acid, potassium, phosphate and fluid. These "uremic toxins" affect almost every organ. Doctors use azotemia to describe high urea and creatinine on blood tests; uremia describes the symptoms that come with it.

Causes

• Chronic kidney disease: most commonly from diabetes and high blood pressure; also glomerulonephritis and polycystic kidney disease
• Acute kidney injury: severe dehydration, sepsis, certain medicines, contrast dye, muscle breakdown
• Urinary tract obstruction: enlarged prostate, stones or tumors blocking both kidneys

Symptoms

General

• fatigue and weakness
• loss of appetite, nausea and vomiting, weight loss
• metallic taste and ammonia-like ("uremic") breath
• generalized itching
• trouble sleeping and restless legs
• muscle cramps and twitching
• swelling of legs and around the eyes
• shortness of breath from fluid overload or anemia
• reduced urine output (though some people pass normal volumes)

Brain and nerves

• poor concentration, memory problems
• confusion, drowsiness, and in severe cases seizures and coma (uremic encephalopathy)
• tingling and numbness in feet (uremic neuropathy)

Heart and blood

• uremic pericarditis: inflammation around the heart causing chest pain and a rubbing sound; an indication for urgent dialysis
• bleeding tendency from poorly functioning platelets
• anemia
• high blood pressure

Skin and bones

• pale or yellowish-brown skin
• in very advanced, untreated cases, a white powder of urea crystals on the skin (uremic frost), now rare
• bone disease from mineral imbalance and secondary hyperparathyroidism

Diagnosis

• blood urea nitrogen (BUN) and creatinine: markedly raised
• estimated glomerular filtration rate (eGFR): usually below 15 mL/min in uremia
• electrolytes: high potassium (hyperkalemia), low bicarbonate (metabolic acidosis), high phosphate, low calcium
• blood count: anemia
• urine tests: protein, blood
• kidney ultrasound: size of kidneys, signs of obstruction
• ECG and echocardiogram for pericarditis or potassium effects

Treatment

Dialysis

Dialysis removes toxins, excess fluid and potassium:

• hemodialysis: usually 3 sessions a week at a center or at home
• peritoneal dialysis: daily exchanges using the abdominal lining as a filter, done at home

Urgent dialysis is needed for uremic pericarditis, encephalopathy, dangerous potassium or acid levels, or fluid overload not responding to medicines.

Kidney transplant

A transplant offers the best long-term survival and quality of life for suitable patients. Living donor transplants can sometimes be done before dialysis is needed.

Managing complications

• low-potassium and low-phosphate diet, and protein and fluid limits as advised by a renal dietitian
• phosphate binders, vitamin D analogs, bicarbonate
• medicines and iron for anemia
• blood pressure control
• treating itching with moisturizers and specific medicines such as difelikefalin for people on dialysis

Conservative kidney management

Some people, particularly older adults with other serious illnesses, choose supportive care without dialysis, focused on symptom control and quality of life.

Prevention

• control blood pressure and blood sugar
• avoid unnecessary NSAIDs and nephrotoxic medicines in kidney disease
• regular kidney function checks if at risk
• early referral to a kidney specialist and timely planning for dialysis access or transplant

Frequently asked questions

What are the symptoms of uremia?

Common symptoms include fatigue, nausea, vomiting, loss of appetite, itching, a metallic taste, ammonia-like breath, muscle cramps, swelling and difficulty concentrating. Severe uremia can cause confusion, seizures, bleeding and chest pain from pericarditis.

What is the difference between uremia and azotemia?

Azotemia means high levels of nitrogen waste products such as urea and creatinine in the blood. Uremia is the clinical syndrome of symptoms and complications caused when these toxins build up from kidney failure.

Can uremia be reversed?

If caused by acute kidney injury or a blockage, uremia can resolve when kidney function recovers. In chronic kidney failure, dialysis or transplant controls uremia but does not restore the native kidneys.

What does uremic breath smell like?

Uremic breath often smells like ammonia or urine, and people may notice a metallic taste. It is caused by urea breaking down into ammonia in the saliva.