Acute Kidney Disease

Acute Kidney Disease

Introduction / Overview

Acute Kidney Disease (AKD) is a sudden decline in kidney function that develops within days to weeks. The kidneys, which normally filter waste products and regulate fluid, electrolytes, and blood pressure, are unable to perform these functions properly. AKD is often used as an umbrella term that includes Acute Kidney Injury (AKI)—a rapid but potentially reversible impairment—and also describes the transitional phase between AKI and Chronic Kidney Disease (CKD).

AKD is important because it may be life-threatening if not recognized and treated promptly. It often complicates other serious medical conditions, increases the risk of chronic kidney problems, and significantly impacts overall health outcomes. Early diagnosis and timely treatment are key to improving recovery.

Anatomy / Background

The kidneys are paired organs located on either side of the spine, just below the rib cage. Each kidney contains about one million nephrons—tiny filtering units responsible for removing toxins and balancing body fluids.

In AKD:

  • Glomeruli (filtration structures) may fail to filter blood effectively.

  • Tubules (responsible for reabsorbing essential substances) may become damaged.

  • Blood vessels supplying the kidneys may be compromised.

When the kidneys fail suddenly, waste products (like urea and creatinine), fluids, and electrolytes build up in the body, leading to complications such as high potassium (hyperkalemia), metabolic acidosis, swelling, and hypertension.

Causes / Etiology

AKD can arise from multiple factors, broadly categorized into three groups:

1. Pre-Renal Causes (Reduced Blood Flow to Kidneys)

  • Severe dehydration (from vomiting, diarrhea, bleeding, or burns)

  • Low blood pressure (shock, sepsis, heart failure)

  • Use of certain medications (NSAIDs, ACE inhibitors, ARBs) that reduce kidney blood flow

2. Intrinsic (Renal) Causes (Direct Kidney Damage)

  • Acute glomerulonephritis (inflammation of kidney filters)

  • Acute tubular necrosis (damage to kidney tubules due to toxins or prolonged ischemia)

  • Drug toxicity (antibiotics, chemotherapy drugs, contrast dyes)

  • Autoimmune diseases (lupus nephritis, vasculitis)

3. Post-Renal Causes (Obstruction of Urine Flow)

  • Kidney stones

  • Enlarged prostate (benign prostatic hyperplasia)

  • Tumors compressing urinary tract

  • Blood clots in the urinary system

Symptoms / Clinical Presentation

Symptoms vary depending on the cause and severity, but common presentations include:

  • Decreased urine output (oliguria) or, rarely, no urine (anuria)

  • Swelling in legs, ankles, or around the eyes

  • Shortness of breath due to fluid accumulation

  • Fatigue, weakness, or confusion

  • Nausea, vomiting, or loss of appetite

  • Chest pain or palpitations (due to electrolyte imbalance)

  • High blood pressure

  • In severe cases: seizures, coma, or cardiac arrest

Diagnosis

Diagnosis of AKD involves a combination of clinical evaluation, laboratory testing, and imaging:

  1. Medical History & Physical Examination

    • Assess fluid status, blood pressure, medication use, recent infections, or toxin exposure.

  2. Laboratory Tests

    • Serum Creatinine & eGFR: To assess kidney filtration capacity.

    • Blood Urea Nitrogen (BUN): Elevated in kidney dysfunction.

    • Electrolytes: Potassium, sodium, calcium, phosphate.

    • Urinalysis: Checks for protein, blood, or signs of infection.

  3. Imaging Studies

    • Ultrasound: Detects obstruction, kidney size, and structure.

    • CT Scan or MRI: For detailed imaging when required.

  4. Kidney Biopsy (select cases)

    • Used when intrinsic kidney disease (e.g., glomerulonephritis) is suspected.

Treatment Options

Treatment focuses on addressing the underlying cause, restoring kidney function, and preventing complications.

Non-Surgical Management

  • Fluid Replacement or Restriction: Depending on whether dehydration or fluid overload is present.

  • Medications:

    • Diuretics for fluid overload

    • Medications to control potassium levels (insulin with glucose, calcium gluconate, potassium binders)

    • Blood pressure control agents

  • Nutritional Support:

    • Low-sodium, low-potassium, and low-protein diet

  • Discontinuing Nephrotoxic Drugs: Avoiding harmful medications such as NSAIDs or certain antibiotics.

Surgical / Procedural Treatments

  • Relief of Obstruction: In post-renal AKD, procedures may include inserting a urinary catheter, stent placement, or surgery to remove kidney stones or tumors.

  • Dialysis: Used in severe or refractory cases when kidneys cannot filter blood adequately.

Procedure Details (if surgical or procedural)

Dialysis

  • Step 1: Vascular access is established via a catheter, fistula, or graft.

  • Step 2: Patient’s blood is drawn and passed through a dialysis machine.

  • Step 3: Waste products, excess fluid, and toxins are filtered out.

  • Step 4: The cleansed blood is returned to the body.

  • Sessions are usually performed several times a week until kidney function recovers or a long-term plan is made.

Obstruction Relief (e.g., Kidney Stone Removal)

  • Step 1: Imaging confirms obstruction site.

  • Step 2: A stent or catheter may be placed to restore urine flow.

  • Step 3: Definitive surgery (lithotripsy, prostate surgery, or tumor removal) is performed if needed.

Postoperative Care / Rehabilitation

Recovery depends on the underlying cause and treatment:

    • Monitoring: Regular checks of urine output, blood pressure, and lab values.

    • Medication Adjustments: Close supervision of diuretics, blood pressure drugs, or dialysis schedule.

    • Nutritional Counseling: Diet tailored to kidney function and electrolyte balance.

    • Infection Prevention: Careful catheter management in patients requiring dialysis.

    • Gradual Rehabilitation: Patients may regain full or partial kidney function over days to weeks.

Risks and Complications

If untreated or poorly managed, AKD can lead to:

  • Permanent kidney damage and progression to CKD

  • Fluid overload causing pulmonary edema and heart failure

  • Severe electrolyte disturbances (especially high potassium) leading to cardiac arrest

  • Uremic complications (confusion, seizures, pericarditis)

  • Increased susceptibility to infections

  • Mortality in severe or untreated cases

Prognosis

The prognosis of AKD varies widely:

  • Favorable: Many patients recover fully if treated promptly and underlying causes are reversible.

  • Partial Recovery: Some patients may regain partial function but remain at risk for CKD.

  • Poor Outcome: Delayed treatment, severe underlying illness, or prolonged obstruction can result in end-stage renal disease requiring long-term dialysis.

When to See a Doctor

Seek urgent medical attention if you experience:

  • Sudden decrease in urine output

  • Severe swelling of legs, face, or abdomen

  • Uncontrolled high blood pressure

  • Persistent nausea, vomiting, or confusion

  • Chest pain, palpitations, or difficulty breathing

  • Known risk factors (diabetes, hypertension, heart failure) with new or worsening kidney-related symptoms

Prompt evaluation can be lifesaving.

Conclusion

Acute Kidney Disease (AKD) is a serious but often reversible condition if recognized early and treated appropriately. Understanding its causes, recognizing symptoms, and seeking timely medical care are crucial to preventing complications. With proper management—including fluid balance, medications, procedures to relieve obstruction, or dialysis—many patients recover kidney function. If you notice warning signs, consult a healthcare professional immediately to ensure the best possible outcome.