Symptoms of Acute Renal Failure

Acute renal failure, known today as acute kidney injury (AKI), is the sudden and often temporary loss of kidney function. It is a condition that develops rapidly over the course of several hours or days and typically occurs in people who are critically ill and already in the hospital.

As the kidneys stop functioning, waste products meant to be filtered from the blood begin to accumulate, setting off a cascade of symptoms including decreased urination, nausea, fatigue, shortness of breath, and swelling due to the retention of fluid.

Some cases of AKI will only have subtle symptoms that are barely felt. Others may be severe and even life-threatening.

Frequent Symptoms

Acute renal failure, now known as acute kidney injury (AKI), doesn’t always cause symptoms and may only be detected by lab tests or sudden changes in urinary output.

Many of the characteristic symptoms of AKI are related to a condition known as uremic encephalopathy in which the accumulation of urea, creatinine, and other substances in the blood trigger disturbances in the brain, affecting not only bodily functions but mental processes, as well.

Other symptoms are caused by imbalances in potassium or fluid levels which directly impact the heart, circulation, and blood pressure.

The common signs and symptoms of AKI may include:

• Decreased urine output
• Swelling of the legs, ankles, and feet (edema)
• Shortness of breath (dyspnea)
• Fatigue
• Loss of appetite
• Nausea and vomiting
• Irregular heartbeats (arrhythmia)
• Chest pain or pressure
• Easy or unusual bleeding (caused by low platelets)
• Confusion
• Seizures
• Coma

Severe cases can lead to death, mostly due to complications of sepsis, respiratory failure, or multiple organ failure.

Prerenal AKI Symptoms

Acute kidney injury can occur for any number of reasons but is broadly classified as being either prerenal (caused by decreased blood flow to both kidneys), intrinsic (caused by damage to the kidneys), or postrenal (due most often to a urinary tract obstruction).

While each will lead to the same outcome—the build-up of toxic waste in the body—the underlying impairment will carry its own set of symptoms, of which AKI would be considered a complication.

The underlying causes can often be differentiated by their symptoms.

Examples of this include:

• Severe dehydration symptoms may include sunken eyes, dry skin, decreased skin elasticity, dry mouth and eyes, rapid heart rate (tachycardia), and dizziness or lightheadedness when standing or sitting up ( orthostatic hypotension).
• Heart failure symptoms may include bulging neck veins, cracking or rattling sounds in the lungs (pulmonary rales), tachycardia, heart palpitations, shortness of breath when lying down, abdominal swelling (ascites), and a persistent cough or wheezing with pink-tinged phlegm.
• Liver cirrhosis symptoms may include ascites, yellowing of the eyes and skin (jaundice), spider veins (spider angioma), sweet- or ammonia-smelling urine, and engorged veins on the surface of the abdomen radiating from the navel (caput medusae).

Intrinsic AKI Symptoms

The most common cause of intrinsic AKI is kidney damage related to such conditions as glomerulonephritis, acute tubular necrosis, and acute interstitial nephritis.

Among some of the differentiating symptoms:

• Glomerulonephritis, the inflammation of blood vessels in the kidneys, may cause symptoms such as pink or bloody urine (hematuria), foamy urine from excess protein (proteinuria), and swelling of the face, hands, feet, and abdomen.
• Acute tubular necrosis (ATN), a condition in which kidney tissues begin to die from the lack of oxygen, can manifest with such symptoms as deep and persistent muscle pain, muscle spasms, a sensation of pins and needles (neuropathy), generalized swelling of the body, and confusion or delirium.
• Acute interstitial nephritis (AIN), the swelling of tissue in between the kidney tubules (often caused by a drug reaction or autoimmune disease), may be accompanied by fever, hematuria, generalized swelling of the body, vomiting, confusion, and a rash (if drug-related).

Postrenal AKI Symptoms

The most common cause of postrenal AKI is a urinary tract obstruction which can be caused by an enlarged prostate gland (benign prostatic hyperplasia), kidney stones, bladder stones, or cancer of the kidneys, bladder, or prostate.

• Benign prostatic hyperplasia (BPH) symptoms include dribbling after urination, excessive urination at night (nocturia), frequent urination, a sense of incomplete bladder clearance, persistent urge to urinate (urinary urgency), or weak urine flow.
• Kidney and bladder stone symptoms include an intense lower abdominal or flank pain, hematuria, cloudy urine, a burning sensation during urination (dysuria), difficulty urinating, and pain or discomfort in the testicles or penis in men.
• Cancer symptoms may include weight loss, hematuria, dysuria, urinary urgency, weak urinary flow, inability to urinate, lower back pain on one side, and bone pain.

When to See a Doctor

While AKI may not cause symptoms and only be discovered when evaluating an unrelated illness, there are certain signs and symptom that may suggest acute kidney failure.

While these symptoms can be caused by any number of medical conditions, none should be considered "normal." It is important to have them checked out.

On the other hand, you should seek immediate emergency care if you experience any of the following:

• Changes in the level of consciousness, including extreme sleepiness, difficulty waking up, or fainting
• Chest pain
• Difficulty breathing
• Severe nausea and vomiting
• Inability to urinate
• Severe bleeding of any sort