This lecture was conducted during the Nephrology Unit Grand Ground by a Sub-intern under Nephrology Division, Department of Medicine in King Saud University. Nephrology Division is NOT responsible for the content of the presentation for it is intended for learning and /or education purpose only.

Tameem M. Ashry

Contents Definition Types Causes Symptoms/Complications

Definition The functions of the kidney are: Removal of waste BP control Electrolyte balance Miscellaneous Vit D synthesis Erythropoetin

Definition Thus, failure of the kidney means inability of the kidney to carry out these functions. It is usually measured-with relative accuracy-by the serum creatinine, BUN and GFR. Acute Renal Failure is failure with rapid decline.

Types The causes of ARF (such as shock or ischemia) act through three main mechanisms of pathology: Prerenal ↓BP,↓Blood flow (ex: HUS) Renal (Intrinsic) Usually a result of Prerenal (ATN) and sometimes Postrenal Glomerular disease Postrenal Obstruction

Causes Prerenal Anything that decreases BP or blood volume with an effect on the kidney. Examples: CHF-↓ blood flow and ↓ pressure =↓perfusion to kidneys too Shock-poor kidney perfusion In later stages the body may sacrifice the kidney to maintain the blood supply to the brain and heart Occlusion- atherosclerosis Fibromuscular dysplasia-thickening of the artery walls

Causes Renal Anything that eventually causes renal damage Examples: ATN (Acute Tubular Necrosis) #1 cause is ischemia (see prerenal failure) Prerenal failure examples: Occlusion Glomerular Disease Wegener’s, Poststreptococcal Interstitial Allergic Interstitial Nephritis

Causes Postrenal Least common Why? Always caused by obstruction and… We have two kidneys So… Both obstructed One functional kidney

Symptoms/Complications 1. ECF volume expansion Due to kidney mistaking initial ischemia for hypovolemia 2. Hyperkalemia Failure means the kidney can no longer excrete K+ 3. Metabolic Acidosis Decreased excretion of H+ too 4. Hypocalcemia and Hyperphosphatemia Where is Vit. D finished? ↑PTH 5. Uremia ↓excretion of nitrogenous waste

Symptoms/Complications The following numbers are results of the causes listed on respective points from the last slide: 1. Causes→Pulmonary Edema #s 1 and 2 are the most common early phase mortal complications 2. Causes → Cardiac arrest 3. Causes → nonspecific symptoms (pain, headache) 4. Causes → Bone demineralisation 5. Causes → Pericarditis, coagulopathy

Thank You I hope it helped!