1. Acute and Chronic Renal Failure
Niazy B Hussam Aldin

2. INTRODUCTION TO ACUTE RENAL FAILURE or injury
acute kidney failure is the rapid loss your kidneys' ability to remove waste and help balance fluids and electrolytes in your body. In this case, rapid means less than 2 days. And it may progress to end stage renal disease, uremic syndrome, and death without treatment.  In most cases ARF is usually asymptomatic and is diagnosed when screening of hospitalized patients reveals a recent increase in serum blood urea nitrogen and creatinine. Recent Research's-  The term acute renal failure (AKI) has largely replaced acute renal failure (ARF), reflecting the recognition that smaller decrements in kidney function that do not result in overt organ failure. The term ARF is now reserved for severe AKI, usually implying the need for renal replacement therapy.

24. Electrolyte Abnormalities
Excretion of Na+ is initially increased, probably due to natriuretic factors
As glomerular filtration rate (GFR) falls, FeNa rises
Maintain volume until GFR <10-20mL/min, then edema
Renal failure with nephrotic syndrome, early edema
Cannot conserve Na+ when GFR <25mL/min, and FeNa rises with falling GFR
3. Tubular K+ secretion is decreased
Aldosterone mediated. Also increased fecal loss of K+ (up to 50% of K ingested)
Cannot handle bolus K+, avoid drugs high K+
Do not use K+ sparing diuretics

25. Bone Metabolism
↓GFR leads to ↑ phosphate ↓ calcium + acidosis
In addition,↑ tubular resorption Ca+ ↑ hypocalcemia
Other defects include acidosis and decreased dihydroxy-vitamin D production
Bone acts as a buffer for acidosis, leading to chronic bone loss in renal failure
Low vitamin D causes poor calcium absorbtion and hyperparathyroidism (high PTH)
Increased PTH maintains normal serum Ca2+ and PO42- until GFR <30mL/min
Chronic hyperparathyroidism and bone buffering of acids leads to severe osteoporosis

26. Other abnormalities
Slight hypermagnesemia with inability to excrete high magnesium loads
Uric acid retention occurs with GFR <40mL/min
Vitamin D conversion to dihydroxy-Vitamin D is severely decreased
Erythropoietin (EPO) levels fall and anemia develops
Accumulation of normally excreted substances, "uremic toxins", MW daltons

27. Associated Problems and Treatment
Immunosuppression
Patients with CRF, even pre-dialysis, are at increased risk for infection
Cell mediated immunity is particularly impaired
Hemodialysis seems to increase immunocompromise
Complement system is activated during hemodialysis
Patients with CRF should be vaccinated aggressively

28. Hypertension
Blood pressure control is very important to slowing progression of renal failure
About 30% of end-stage renal disease (ESRD) is related to hypertension
Overall risk of CRF with creatinine >2.0mg/dL is ~2X in five years with HTN
Patients with grade IV (severe) HTN have 22X increased risk vs. normal for CRF
Targetted mean pressure 92-98mm Hg in patients with renal failure and proteinuria
Patients with HTN and albuminuria >1gm/day, blacks, diabetics have higher ESRD risk

30. Note- All cases of both chapter 17and 18 are included