Chapter 28: Acute Kidney Injury and Chronic Kidney Disease Flashcards
1
Q
Acute Kidney Injury
A
- formerly called acute kidney failure
- known as AKI
- Broad spectrum of kidney disease ranging form minor changes in renal function to complete renal failure requiring renal replacement therapy
2
Q
Sudden reduction of kidney function causes
A
- disruptions in fluid, electrolyte, and acid-base balances
- retention of nitrogenous waste products (comes from breakdown of protein which leads to eleveted BUN)
- increased serum creatine
- decreased glomerular filtration rate (GFR)
3
Q
Acute Kidney Injury additional info
A
- results in characteristic alterations in laboratory tests of blood and urine
- Renal function monitored by serum creatine and calculated GFR (serum creatine is most reliable lab testing to identify renal failure)
- Retention of metabolic wastes (azotemia/uremia); monitored by the BUN, produces widespread systemic effects (uremic syndrome)
4
Q
Etiology and Pathophysiology of Acute Kidney Injury
A
- abrupt reduction in renal function producing an accumulation of waste materials in the blood
- May be due to aging, associated with comorbidities, or due to insults to the kidney
- 3 sites of disruption (1. renal perfusion 2. urine flow distal to the kidney 3. circumstances within the kidney blood vessels, tubules, glomeruli, or interstitium)
- Distinction between the sites of disruption helps determine appropriate therapy
5
Q
Prerenal Kidney Injury
A
- Due to conditions that diminish perfusion of the kidney (hypovelemia, hypotension, heart failure, renal artery obstruction, fever, vomiting, diarrhea, burns, overuse of diuretics, edema, ascites, and drugs including ACE inhibitors, angiotensin II blockers, and NSAIDs)
- Characterized by low GFR, oliguria (less than 30 ccs urine/hr), high urine specific gravity and osmolality, and low urine sodium
- prolonged prerenal ARF leads to acute tubular necrosis
6
Q
Postrenal Kidney Injury
A
- due to obstruction within the urinary collecting system distal to the kidney (stones); elevated pressure in the bowman capsule; impedes glomerular filtration
- clinical findings based on duration of the obstruction
- Prolonged postrenal ARF leads to acute tubular necrosis (intrinsic) and if continues leads to irreversible kidney damage
7
Q
Intrinsic/Intrarenal Kidney Injury
A
- due to primary dysfunction of the nephrons and the kidney itself
- most common problem withing the renal tubules resulting in ACUTE TUBULAR NECROSIS (ATN); may also occur with glomerular, vascular, or interstitial etiologies
- ATN causes include nephrotoxic insult and ischemic insults
- Vascular Pathophysiological processes include decreased renal blood flow, hypoxia, and vasoconstriction
- tubular pathophysiological processes include inflammation and reperfusion injury, causes casts, obstructs urine flow, tubular backleak
- can repair itself or if injury is sustained leads to end-stage renal disease
8
Q
Clinical Presentation of Acute Tubular Necrosis
A
- Divided into three phases (prodromal, oliguric, and post-oliguric)
- clinical presentation varies with the phase
- laboratory findings can help differentiate prerenal from intrinsic/intrarenal kidney injury
9
Q
Prodromal Phase
A
- normal or declining urine output
- serum BUN and creatine begin to rise
- Insult to the kidney has occurred and the duration of this phase will vary depending on cause of injury, amount of the toxin ingested, and duration and severity of the hypotension
10
Q
Oliguric Phase
A
- may last up to 8 weeks with usual urine output 50-400 mL/day
- characterized by oliguria and progressive uremia; decreased GFR; Hypervolemia (have signs and symptoms of fluid excess, hyperkalemia, and uremic syndrome)
- typically may last 1 to 2 weeks
- dialysis may be required
11
Q
Post-Oliguric Phase
A
- termination of oliguric phase represents renal recovery
- sadly, not all recover from it
- urine volume increases (diuresis); tubular function impaired and azotemia continues
- fluid volume deficit until kidneys recover
- may last 2 to 10 days, full recovery takes around 1 year
(full recovery shows normal levels of BUN and creatine. Usually a degree of renal insufficiency persisits)
12
Q
Chronic Kidney Disease
A
- Outcome of progressive an irrevocable loss of functional nephrons
- Progressive processes (Chronic Kidney Disease - chronic renal failure - end stage renal disease) (ESRD requires dialysis) (#1 REASON FOR ESRD IS HAPETIC NEUROPATHY)
- a global health problem often linked with other comorbidities, primarly hypertension and diabetes mellitus (highest risk for developing CKD)
- Defined as decreased kidney function or kidney damage of 3 months duration based on blood tests, urinalysis, and imaging studies
- also defined as GFR
13
Q
Risk Factors of Chronic Kidney Disease
A
- diabetes
- hypertension
- recurrent pyelonephritis
- glomerulonephritis
- family history of CKD
- History of exposure to toxins
- age over 65
- ethnicity
14
Q
Pathophysiology of Chronic Kidney Disease
A
- PROGRESSIVE AND IRREVERSIBLE
- GFR reduction occurs with nephron loss (kidneys compensate until 75% to 80% of nephrons are damaged/nonfunctional)
- Progression is monitored by a staging system
- 5 stages of progression and with each higher stage the GFR and kidney function declines
15
Q
Stages of Chronic Kidney Disease
A
- Stage 1 and stage 2 focuses on minimizing risk factors
- stage 3 symptoms may be starting to appear and treatment may be needed
- in stage 4 planning for dialysis or transplant should begin
- in stage 5 renal replacement therapy needed or death will ensue
