Acute Kidney Injury (AKI) | Etiology, Pathophysiology, Clinical Features, Diagnosis, Treatment

The video begins with an introduction to acute kidney injury (AKI), explaining its causes and effects on the body. The kidneys' role in excreting metabolic waste products like urea and creatinine is discussed, along with the consequences when their function is impaired due to injury. The importance of understanding different types of AKI, including pre-renal, intra-renal, and post-renal, is emphasized to grasp the topic comprehensively.

This paragraph delves into pre-renal AKI, which is caused by reduced blood flow to the kidneys. Conditions like heart failure, liver failure, and sepsis are highlighted as potential causes. The discussion covers how these conditions lead to decreased effective arterial blood volume, consequently affecting kidney function and leading to an increase in blood urea nitrogen (BUN) and creatinine levels, as well as a decrease in urine output.

The focus shifts to situations where low total body volume, rather than low effective arterial blood volume, leads to AKI. Causes such as severe vomiting, diarrhea, dehydration, excessive sweating, severe burns, and blood loss are discussed. The paragraph explains how these conditions reduce the total blood volume, lowering blood pressure and perfusion to the kidneys, which can induce AKI.

The paragraph discusses large vessel blockages as a cause of pre-renal AKI. It covers conditions like atrial fibrillation (AFib) leading to clot formation, renal artery stenosis, and renal artery fibro muscular dysplasia. These blockages reduce blood flow to the kidneys, resulting in AKI, with a focus on the importance of understanding the renal artery's role in kidney perfusion.

Intrarenal AKI, caused by direct damage to the kidney tubules or blood vessels, is explored. The paragraph covers the most common cause, acute tubular necrosis (ATN), and its association with prolonged low blood flow, certain medications like aminoglycosides and vancomycin, and conditions like sepsis. The impact of these factors on kidney function and the development of casts that block kidney tubules is detailed.

The video outlines the diagnostic process for AKI, including differentiating between pre-renal, intra-renal, and post-renal causes. It emphasizes the importance of patient history, physical examination, urinalysis, urine electrolytes, and imaging studies like renal ultrasound or CT scans. The paragraph also touches on the KDIGO guidelines for defining AKI based on creatinine levels and urine output.

This paragraph covers the treatment strategies for different types of AKI. It discusses managing pre-renal AKI through diuretics and inotropic agents, treating intra-renal AKI by addressing the underlying cause such as nephrotoxin exposure or hemolysis, and post-renal AKI treatment which may involve medication adjustments or procedures like catheterization. The role of dialysis in severe cases is also introduced.

The video concludes with a discussion on complications associated with intra-renal AKI, such as severe acidosis, hyperkalemia, drug intoxication, and volume overload. It explains that in cases where the kidneys fail to recover, dialysis may be necessary. The two main types of dialysis, continuous renal replacement therapy (CRRT) and intermittent hemodialysis, are described, along with the situations in which each is used.