Definition

Acute kidney injury (previously known as acute kidney failure) is a condition of the kidneys characterized by the loss of their ability to effectively remove excess salts, fluids, and metabolic waste products from the blood. The kidneys play a crucial role in eliminating these substances from the body.

When the kidneys fail to perform their filtering and excretory functions, fluid and waste products can accumulate, posing a serious risk to the body. This accumulation can lead to imbalances in electrolytes and an increased mortality risk.

Acute kidney injury typically occurs in individuals receiving hospital treatment and can develop rapidly, manifesting within hours, days, or weeks. Patients with severe illnesses requiring intensive care are at the highest risk of developing acute kidney injury.

While acute kidney injury can be life-threatening and necessitate intensive treatment, it is reversible. This means that if the patient's overall health improves, kidney function may potentially recover.

Causes

Acute kidney injury (AKI) can occur for several reasons. Some of these include:

• Acute tubular necrosis (a structural kidney injury)
• Severe or sudden dehydration
• Exposure to certain toxins or medications that are toxic to the kidneys
• Autoimmune kidney diseases such as acute nephritis syndrome and interstitial nephritis (kidney infections)
• Urinary tract obstruction (blocked urinary tract)

Additionally, decreased blood flow to the kidneys can impair their function. Medical conditions that can lead to decreased blood flow include:

• Low blood pressure
• Burns
• Dehydration
• Bleeding
• Trauma
• Septic shock
• Certain serious illnesses
• Surgical procedures

Furthermore, several medical conditions can cause blockages in the blood vessels of the kidneys, leading to acute kidney failure. These conditions include:

• Hemolytic uremic syndrome
• Idiopathic thrombocytopenic purpura (a disorder causing easy bruising or bleeding)
• Malignant hypertension (hypertensive urgency where blood pressure can reach 180/120 mmHg or higher)
• Transfusion reactions
• Scleroderma

Risk factor

Several factors can increase the risk of AKI, including:

• Advanced age
• Hospitalization, especially for serious illnesses requiring intensive care
• Blockage of blood vessels in the arms or legs (peripheral artery disease)
• Pre-existing kidney disease
• Liver disease
• Diabetes, especially with poorly controlled blood sugar levels
• High blood pressure
• Heart failure
• Obesity
• Cancer and its treatments
• Undergoing or post-operative cardiac, abdominal surgery, or bone marrow transplantation, which can also increase the risk of acute kidney injury

Symptoms

The symptoms of acute kidney failure may include:

• Decreased urine output, although it may sometimes remain normal
• Fluid retention, leading to swelling in the legs, ankles, back, or feet
• Shortness of breath
• Irregular heartbeats
• Chest pain
• Bad breath
• Fatigue
• Hip pain
• Tremors in the hands
• Easy bruising
• Changes in consciousness or mood, especially in the elderly
• Decreased appetite
• Decreased sensation, especially in the hands and feet
• Prolonged bleeding
• Seizures or coma in severe cases
• Nausea and vomiting
• High blood pressure
• Metallic taste in the mouth

Diagnosis

The diagnosis of acute kidney failure can be established through medical interviews, physical examinations, and, if necessary, additional diagnostic tests.

During a medical interview, the doctor will inquire about the symptoms experienced by the patient. If the symptoms suggest acute kidney failure, the doctor will perform a physical examination. In cases of acute kidney failure, the doctor may observe swelling in the body, especially around the eyelids and ankles.

To confirm the diagnosis, the doctor may perform several additional tests, including:

• Measurement of urine output: This test measures the amount of urine excreted over 24 hours.
• Urine tests: Analyzing a urine sample to detect abnormalities that may indicate acute kidney failure.
• Blood tests: These tests assess kidney function by measuring the levels of urea and creatinine in the blood, which are indicators of acute kidney failure.
• Imaging studies: such as ultrasound (USG) and CT scans, can be conducted to visualize the kidneys more clearly or to determine if there is any obstruction in the urinary tract.
• Kidney biopsy: In some cases, the doctor may take a sample of kidney tissue to examine it under a microscope.

Management

The therapy for AKI depends on the underlying cause, intending to restore kidney function to normal and prevent fluid accumulation and metabolic waste products. Several approaches may be taken in cases of acute kidney injury:

• Diet: Your doctor may recommend limiting fluid intake and certain foods to reduce the buildup of waste products normally eliminated through the kidneys. A high-carbohydrate, low-protein, low-salt, and low-potassium diet may be advised.
• Medications: Prescribed medications may include antibiotics to prevent concurrent infections. Diuretic medications can help the kidneys eliminate excess fluid, and calcium and insulin may be administered to lower high blood potassium levels if necessary.
• Dialysis: If needed, your doctor may recommend dialysis, which can be temporary. Dialysis helps remove waste products and excess fluids from the blood when the kidneys cannot perform this function adequately.

Complications

Some complications that can occur as a result of acute kidney failure include:

• Chronic kidney failure
• Heart damage
• Nervous system damage
• End-stage kidney disease
• High blood pressure

Prevention

Acute kidney failure is often difficult to predict or prevent. However, you can reduce your risk by taking care of your kidneys:

• Follow medication instructions: Pay attention to your medications' dosing and usage instructions. Follow your doctor's advice carefully, as some medications can interfere with kidney function.
• Consult your doctor: Talk to your doctor about how to care for your kidneys, especially if you have chronic conditions such as high blood pressure and diabetes. Undergo regular treatment for chronic diseases to prevent kidney failure.
• Maintain a healthy lifestyle: Adopting a healthy lifestyle, including regular exercise, eating a balanced diet, and avoiding excessive alcohol consumption, can contribute to overall kidney health.

When to see a doctor?

If you experience worsening symptoms such as swelling spreading from the eyelids and ankles, as well as a reduction or cessation of urine production, it is advisable to consult the doctor. You may consider seeing a doctor in internal medicine (internist) or nephrologist specializing in kidney and hypertension conditions.

The doctor will conduct a medical interview, physical examination, and possibly additional diagnostic tests to establish an accurate diagnosis of the underlying disease. This comprehensive approach will help plan appropriate management strategies tailored to your needs.

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