Acute Kidney Injury Explained : Causes - Stages And Prevention

In this article, we’re discussing acute kidney injury (AKI) — what it is, its causes, and how it's managed.

What is Acute Kidney Injury?

AKI is a sudden, often reversible, decline in the glomerular filtration rate (GFR), leading to elevated levels of blood urea nitrogen (BUN) and creatinine.

According to KDIGO guidelines, AKI is defined by any of the following:

1. An increase in creatinine of ≥26.5 micromoles per liter within 48 hours.
2. An increase in creatinine to ≥1.5 times the baseline within the past 7 days.
3. Reduced urine output: Less than 0.5 milliliters per kilogram per hour for over 6 hours.

In essence, AKI reflects an abrupt, reversible decline in kidney function that leads to increased BUN and creatinine levels.

Stages of AKI

AKI progresses through stages based on the severity of kidney function impairment:

• Stage 1:

  • Creatinine increase to 1.5–1.9 times baseline or ≥26.5 micromoles per liter.
  • Urine output <0.5 mL/kg/hr for 6–12 hours.

• Stage 2:

  • Creatinine increase to 2–2.9 times baseline.
  • Urine output <0.5 mL/kg/hr for >12 hours.

• Stage 3:

• Creatinine increase to ≥3 times baseline or ≥352.6 micromoles per liter.
• Urine output <0.3 mL/kg/hr for >24 hours, or dialysis is required.
• GFR reduction to <35 mL/min/1.73m².

Causes of AKI

AKI can be classified into three main categories based on the origin of the dysfunction:

1. Prerenal Causes

These involve reduced blood flow to the kidneys, often due to:

• Decreased cardiac output (e.g., myocardial infarction, pericardial tamponade).
• Shock (systolic BP <90 or diastolic BP <60 mmHg), caused by dehydration, hemorrhage, or fluid loss.
• Arterial obstruction (e.g., renal artery stenosis).
• Medications:
  • ACE inhibitors/ARBs cause efferent vasodilation.
  • NSAIDs reduce blood flow by pre-glomerular vasoconstriction.

2. Intrarenal Causes

These result from direct kidney damage, categorized by kidney structures:

• Glomerular damage: Glomerulonephritis.
• Tubular injury:
  • Ischemic or nephrotoxic acute tubular necrosis (ATN).
  • Myeloma cast nephropathy.
• Interstitial damage: Often drug-induced or caused by conditions like sarcoidosis.
• Vascular issues: Renal vein thrombosis or thrombotic microangiopathies.

3. Postrenal Causes

These occur due to urine flow obstruction, leading to kidney damage, such as:

• Kidney stones (renal calculi) anywhere along the urinary tract.
• Malignancies causing blockage.
• Benign prostatic hyperplasia (BPH) or urethral strictures, causing urinary retention and hydronephrosis.

Differentiating Prerenal, Intrarenal, and Postrenal AKI

Diagnostic clues can help identify the cause:

• Prerenal AKI:

  • BUN
    ratio >20.
  • Fractional excretion of sodium (FENa) <1%.
  • Urine osmolality >500 mOsm/kg.
  • Bland urine sediment.

• Intrarenal AKI:

  • BUN
    ratio <20.
  • FENa >2%.
  • Urine osmolality <400 mOsm/kg.
  • Granular casts in urine sediment.

• Postrenal AKI:

• Symptoms include inability to urinate or pain (renal colic).
• Imaging (e.g., ultrasound) may show hydronephrosis or dilated ureters.

Prevention and Management of AKI

Key strategies include:

1. Identifying high-risk patients (e.g., those with chronic kidney disease).
2. Avoiding nephrotoxic drugs (e.g., NSAIDs, ACE inhibitors/ARBs).
3. Ensuring adequate hydration in prerenal cases.
4. Monitoring drug levels for nephrotoxic medications (e.g., aminoglycosides, vancomycin).
5. Minimizing the use of IV contrast in at-risk patients or providing proper hydration if contrast is necessary.

Kidney Infection Signs & Symptoms You Should NEVER Ignore | Acute Pyelon...

What is Acute Pyelonephritis?

Acute pyelonephritis refers to a bacterial infection and inflammation of the kidney. It is a relatively common condition affecting the kidneys, often caused by an ascending urinary tract infection (UTI), also known as cystitis. In some cases, a UTI progresses upward through the urinary tract, ultimately infecting and inflaming the kidneys.

Certain groups are more at risk of developing pyelonephritis, including women, pregnant individuals, and those with recurrent kidney stones.

Symptoms of Kidney Infection

The symptoms of acute pyelonephritis typically appear within hours or over the course of a day. Here are the most common signs and symptoms:

1. Flank Pain

   • Flank pain is a hallmark symptom, felt on one side of the back near the bottom edge of the rib cage, where the kidneys are located.
   • This pain may also be referred to as costovertebral angle (CVA) tenderness, which clinicians can detect by gently tapping this area.

2. Fever and Chills

   • As a kidney infection is bacterial in nature, it often causes fever and chills.

3. Nausea and Vomiting

   • These symptoms frequently occur due to the severity of the infection. Patients often feel very unwell and may experience reduced appetite (anorexia), compounding their discomfort.

4. Hematuria (Blood in the Urine)

   • Hematuria, which can be microscopic or macroscopic, is a common finding. In most cases, blood in the urine is not visible to the naked eye but can be detected through a urine test. This occurs due to irritation caused by the infecting organisms. Hematuria is more common in females and affects about 30–40% of patients with pyelonephritis.

5. Abdominal Pain

   • Abdominal pain, including epigastric pain (above the belly button) or lower abdominal pain, may occur. This can sometimes result from referred pain from the kidney or an associated UTI.

6. Urinary Symptoms

   • Symptoms related to an underlying UTI may accompany pyelonephritis, such as:
     • Dysuria: Pain or burning sensation during urination.
     • Urinary Urgency: A frequent urge to urinate.
     • Urinary Frequency: Frequent urination with small volumes, even when the bladder is empty.

Rare and Severe Complications

In severe cases, complications can arise, including:

• Bacteremia: Bacteria entering the bloodstream, potentially causing systemic infection.
• Sepsis or Septic Shock: A life-threatening response to infection, potentially leading to organ dysfunction.
• Acute Renal Failure: Damage to the kidney that reduces its function.

Summary

Kidney infections or acute pyelonephritis present with a range of symptoms, from flank pain and fever to nausea, vomiting, and urinary issues. Early recognition and treatment are essential to prevent severe complications, such as sepsis or kidney failure.

Kidney (Renal) Disease Signs & Symptoms

In this article, we’ll cover the signs and symptoms of kidney disease, also known as renal disease. We’ll look at a range of symptoms, starting from early-stage kidney disease up to kidney failure. Let’s begin with one of the most common symptoms: changes in urination patterns.

Urinary changes are often one of the earliest signs. For example, some kidney conditions may cause an increase in urine volume, leading to more frequent urination. Conversely, in more advanced stages of kidney disease, urine output may decrease. Additionally, conditions affecting the kidneys can lead to foamy urine, indicating the presence of protein, or even blood in the urine, a condition known as hematuria.

Another notable sign of kidney disease is peripheral edema, which appears as swelling, often in the lower limbs. This happens because fluid builds up in tissue spaces due to volume overload, often associated with advanced kidney disease. When the kidneys aren’t removing enough fluid, it can accumulate in tissues. Peripheral edema is also common in nephrotic syndrome, where the loss of albumin - a protein that helps regulate fluid - leads to fluid retention in tissues.

Kidney disease can also cause hypertension, or high blood pressure, due to increased blood volume from inadequate fluid removal. This excess fluid may also lead to shortness of breath, known as dyspnea, if it accumulates in the chest cavity and around the lungs. Additionally, some patients may experience chest pain, often related to fluid overload.

Other symptoms of kidney disease include sleep issues, often caused by increased toxins in the bloodstream. Individuals may struggle to fall asleep, wake frequently, or feel fatigued during the day. This fatigue, partly due to accumulated toxins, is also linked to anemia, which we’ll discuss shortly. Anemia in kidney disease is due to the kidney’s decreased ability to produce erythropoietin (EPO), a hormone that stimulates red blood cell production. With less EPO, fewer red blood cells are produced, leading to fatigue.

Muscle twitching and spasms can also occur, resulting from electrolyte imbalances since the kidneys play a key role in maintaining electrolyte balance. Low calcium and high phosphate levels, common in kidney disease, can contribute to these spasms.

As kidney function declines, urea - a byproduct of protein metabolism accumulates in the blood, causing uremia. This elevated urea can lead to complications, such as uremic pericarditis (inflammation of the pericardium) and uremic encephalopathy (brain dysfunction that can cause delirium or confusion). Uremic encephalopathy may present with asterixis, a tremor or "flapping" of the wrists due to postural instability.

Pruritus, or severe itching, is another symptom, often resulting from high urea levels. Patients may develop scratch marks, also known as uremic pruritus. Uremia can also cause nausea, vomiting, and a loss of appetite, which may lead to weight loss.

Finally, kidney disease can lead to platelet dysfunction due to uremia, increasing the risk of bleeding. Despite normal platelet counts, the platelets may not function properly, leading to symptoms such as bleeding gums, easy bruising, and nosebleeds. Superficial bleeding may appear as petechiae (small red spots) or purpura (larger purple spots) on the skin.

I hope you found this article informative. 

Skin Tags (Acrochordons) Causes - Risk Factors - Symptoms - Diagnosis An...

Skin Tags (Acrochordons) Causes - Risk Factors - Symptoms - Diagnosis And Treatment 

Skin tags, also called acrochordons, are common, benign skin growths that frequently appear in the general population. Various factors increase the likelihood of developing skin tags, including aging and specific health conditions such as obesity and diabetes. 

In this video we will explore additional risk factors, theories behind why skin tags form, associated signs and symptoms, diagnostic methods, and treatment options available to clinicians. We hope you find this lesson informative. If you do, please like and subscribe for more content like this - https://www.youtube.com/watch?v=kL2hMNeP7PY

How to Remove Skin Tags AT HOME | Get Rid of Skin Tags NOW

Skin tags, otherwise known as acrochordons, soft fibromas, or fibroepithelial polyps are harmless growths that can appear anywhere on your skin, but often develop on the neck, eyelids, or underarms. They Usually appear on areas with a lot of friction and areas where the skin overlaps itself, like the neck folds for example. Which is a very common place. And they hang from the surface of the skin on a thin piece of tissue called a stalk - https://www.youtube.com/watch?v=OUzo9X-7RV8

What Causes Skin Tags? Are Skin Tags Normal?

There are estimates that almost 50 to 60% of adults will develop at least one skin tag in their lifetime. The probability of their occurrence actually increases when youre about 40 years old. I think a good place to start is finding out why they keep occurring. If you figure out why they keep occurring, you can spend less time on removing them. And there are about 4 reasons. The first is if you have unmanaged diabetes, second: obesity, third is: metabolic syndrome, and fourth is: if you have a family history of skin tags. Treating these underlying conditions, especially if there is insulin resistance involved in the body, can be a great place to start. 

12 Best Foods to REVERSE Kidney Damage & BOOST Kidney Health

Discover the top 12 foods that can help reverse kidney damage and promote long-term kidney health! 🥗 Kidneys play a vital role in cleansing toxins, balancing electrolytes, and maintaining blood pressure. With millions at risk for chronic kidney disease, knowing which foods to incorporate into your diet is essential.

In this video, we’ll cover each food’s unique benefits—like red bell peppers for antioxidants, garlic for its anti-inflammatory effects, and berries to help prevent urinary tract infections. Learn how these ingredients can reduce kidney stress, regulate blood sugar, and improve overall wellness. Paired with lifestyle choices and medical guidance, these foods can be a game-changer for anyone looking to support kidney health naturally.

#kidneyhealth 

#healthykidneys 

#ckd 

Be sure to watch to the end to understand how these foods work with your kidneys’ natural functions to prevent kidney disease. Whether you’re looking to prevent kidney damage, manage existing kidney conditions, or just understand more about how your kidneys keep your body healthy, this guide is for you! Remember to subscribe and join us on the journey to a healthier you. 🌿

What Causes Skin Tags? (What SKIN TAGS Really Mean)

Did you know those tiny skin tags might be telling you more than you think about your health? In this short, discover the surprising link between skin tags and serious metabolic health risks that many people—and even some doctors - are unaware of. 

Millions of people have skin tags, but few realize that their presence could signal a deeper, underlying issue such as metabolic syndrome, insulin resistance, or even prediabetes. Learn why these small skin growths appear and how changing your diet could make a big difference. Watch to find out more and see real results from viewers who’ve tackled this issue naturally!

If you've noticed more skin tags appearing or simply want to know more about their causes, this video is for you. Subscribe for more health insights that make a real impact. Leave a comment with your own experiences - let’s connect and spread the knowledge on wellness tips that work