Acute kidney injury

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What is Acute kidney Injury (AKI)?

Acute Kidney Injury (AKI) is a sudden decline in kidney function that occurs over hours to days. The kidneys lose their ability to filter waste, regulate fluids, electrolytes, and blood pressure effectively. AKI can range from mild and reversible to severe, potentially leading to life-threatening complications if not promptly identified and treated.

AKI often occurs in hospitalized patients or those with severe illness, but it can also develop in the community due to dehydration, infections, or medications that affect kidney function. Early recognition is crucial because rapid intervention can often reverse the injury and prevent permanent kidney damage.

Is Acute kidney injury common?

AKI is relatively common, especially among hospitalized patients, affecting 10–15% of adults in hospital settings. Risk is higher in individuals with chronic kidney disease, diabetes, hypertension, heart disease, or older age. Even mild AKI episodes can increase the risk of future CKD or long-term kidney problems.

Can Acute kidney injury be cured?

In many cases, AKI is reversible if the underlying cause is treated promptly. Recovery may take days to weeks, depending on severity, overall health, and promptness of intervention. However, severe AKI can lead to permanent kidney damage or the need for long-term dialysis.

Causes

What causes Acute Kidney Injury?

AKI typically develops due to one or more of the following:

Prerenal causes

  • Reduced blood flow to the kidneys (e.g., dehydration, heart failure, sepsis, blood loss).

Intrinsic (renal) causes

  • Acute tubular necrosis (ATN), often due to ischemia or toxins (drugs, contrast dye, certain antibiotics).
  • Glomerular diseases, including glomerulonephritis.
  • Interstitial nephritis, often from medications or autoimmune reactions.

Postrenal causes

  • Obstruction of urine flow (kidney stones, enlarged prostate, tumors).

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*Price Effective 12/1/2025
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Follow Up

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Symptoms

What are the symptoms of Acute Kidney Injury?

Symptoms can be subtle and may include:

  • Reduced urine output (oliguria: <0.5 mL/kg/hour for 6 hours is concerning)
  • Swelling in legs, ankles, or around the eyes
  • Fatigue and weakness
  • Nausea or vomiting
  • Confusion or altered mental status
  • Shortness of breath (due to fluid overload)
  • High blood pressure

Severe AKI can lead to electrolyte imbalances, fluid overload, metabolic acidosis, and uremia, which are medical emergencies.

Diagnosis

How is Acute Kidney Injury diagnosed?

Diagnosis relies on laboratory testing, imaging, and sometimes kidney biopsy:

Blood tests

  • Creatinine: Rapid rise indicates decreased kidney function
  • BUN (Blood Urea Nitrogen)
  • Electrolytes (potassium, sodium, bicarbonate)

Urine tests

  • Urinalysis: detects protein, blood, or sediment
  • Urine output monitoring

Imaging

  • Ultrasound: identifies obstruction or structural abnormalities

Other tests

  • Kidney biopsy: sometimes required if intrinsic renal disease is suspected

AKI is staged according to KDIGO guidelines based on serum creatinine rise and urine output to guide management.

Treatment

How is Acute Kidney Injury treated?

Treatment depends on the underlying cause and severity:

Supportive care

  • Correct fluid imbalance (IV fluids for dehydration, diuretics for fluid overload)
  • Adjust medications that affect kidney function
  • Maintain electrolyte balance

Specific interventions

  • Treat underlying infections
  • Remove obstruction (e.g., relieve enlarged prostate, remove stones)
  • Address autoimmune or glomerular causes if present

Advanced therapies

  • Dialysis may be necessary for severe AKI with life-threatening electrolyte disturbances, fluid overload, or uremia.

When to seek urgent care

Seek immediate medical attention for:

  • Chest pain
  • Severe shortness of breath
  • Confusion or altered mental status
  • Rapidly declining urine output

References

  • Kidney Disease: Improving Global Outcomes (KDIGO) — AKI clinical practice guidelines
  • National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK) — Acute Kidney Injury overview
  • Mayo Clinic — Acute kidney injury: symptoms, causes, diagnosis, and treatment
  • National Kidney Foundation — AKI patient education

Medically reviewed by:

Dr. Javeed Siddiqui, MD, MPH

Dr. Siddiqui is the Chief Medical Officer at TeleMed2U responsible for clinical and technical program development as well as maintaining a thriving telemedicine practice in infectious diseases which includes specialized care of Hepatitis and HIV.

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Affordable – with or without insurance

With Insurance

Nephrology

Your copay
Depending on insurance

Without Insurance

*Price Effective 12/1/2025
$169
Initial Visit
$109
Follow Up

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