Chronic Kidney Disease (CKD) Pathophysiology

The video begins by defining chronic kidney failure, also known as chronic kidney disease, as a condition where there is an irreversible loss of nephrons, the functional units of the kidneys. This can lead to a toxic state in the body. The anatomy of the kidneys is reviewed, including their connection to the ureter, bladder, and major blood vessels. The causes of chronic kidney failure are discussed, which include acute kidney injury, hypertension, diabetes, and other kidney diseases like polycystic kidney disease. Acute kidney failure is highlighted as potentially reversible and is categorized into pre-renal, intra-renal, and post-renal causes, each with specific contributing factors. The video also explains how hypertension can lead to chronic kidney failure by causing thickening of blood vessels and a decrease in the glomerular filtration rate, eventually activating the renin-angiotensin-aldosterone system.

The second paragraph delves into the most common cause of chronic kidney failure: diabetes, and its complication, diabetic nephropathy. The changes observed in diabetic nephropathy include mesangial expansion, proliferation, foot process effacement, glomerular basement membrane thickening, and sclerosis. These changes are linked to high blood glucose levels, which lead to the overproduction of reactive oxygen species and oxidative stress. The video illustrates how the loss of nephrons results in increased blood flow to the remaining functional nephrons, causing glomerular hyperfiltration. Over time, this hyperfiltration can lead to further sclerosis and loss of nephrons, continuing the cycle of kidney damage. The clinical manifestations of chronic kidney failure, such as uremia, are also introduced.

This section of the video addresses the clinical manifestations of chronic kidney failure, focusing on the disruptions in sodium and water balance, and potassium balance. A decrease in glomerular filtration rate (GFR) leads to increased retention of sodium and water, causing high blood pressure and peripheral edema. The importance of fluid restriction and the dangers of vomiting and diarrhea in patients with chronic kidney failure are emphasized. Additionally, the decrease in GFR results in hyperkalemia due to increased potassium retention, which can cause muscle weakness and ECG changes. The loss of nephrons also leads to a decrease in aldosterone production, disrupting the sodium-potassium pump and exacerbating potassium retention. The use of potassium-sparing diuretics and ACE inhibitors is cautioned against in this context.

The video continues by discussing metabolic acidosis, which occurs when the capacity to excrete hydrogen and generate bicarbonate is diminished in chronic kidney failure. This condition can lead to bone decalcification and other complications. The role of the nephron in maintaining the body's pH balance is explained, and the consequences of its failure are outlined. Mineral imbalance and osteodystrophy are also covered, with the loss of nephrons leading to decreased calcitriol production, hypocalcemia, and secondary hyperparathyroidism. The latter contributes to bone breakdown and osteodystrophy. Uremia, a condition characterized by high levels of urea in the blood due to kidney failure, is described, including its neurological and dermatological symptoms. The video concludes by summarizing the clinical manifestations of chronic kidney failure and thanking viewers for their attention.