11.2: Clinical I Flashcards
Definition of AKI?
Any of the following renal changes within 48 hours:
- Serum Cr. increase > .3 mg/dl
- % increase serum Cr. > 50%
- Oliguria 6 hours
What is RRT?
- Renal replacement therapy: Dialysis
What is AKI often associated with?
- Critically ill patients
- Septic patients: 50% with bacteremic septic shock
- MSOD: mult. syst. organ dysfunction
3 categories of AKI?
- Prerenal
- Intrinsic renal
- Postrenal
Types of prerenal failure / azotemia?
- Absolute decrease in BV: hemorrhage / depletion
- Low ECV: relative decrease in BV: CHF / cirrhosis
- Renal stenosis / occlusion
- Impaired autoregulation: NSAID/ACEI/ARB
Types of intrinsic renal failure?
- Vascular
- Acute glomerular disease
- AIN: acute interstitial nephritis
- ATN: acute tubular necrosis
Types of postrenal failure
- Bladder outlet obstruction
- Bilateral ureteral obstruction
- Unilateral ureteral obstruction
Most common causes of AKI?
- Prerenal azotemia
- Ischemic ATN
* **75% of all cases
- Thought that prerenal azotemia becomes ischemic ATN
What is prerenal azotemia?
- Appropriate physiologic response to renal hyperperfusion: success not failure
What does prerenal azotemia progress to?
Ischemic ATN
What is normal renal autoregulation in response to drop in BP? What mediates this?
- Dilation of afferents: NO and prostaglandins
2. Constriction of efferents
What antagonizes auto dilation of renal afferents? efferents
Affernets: COX I/II inhibitors: NSAIDS
Efferents: ACEI / ARBs
What is the NSAID effect?
- NSAIDs cause tonic constriction of renal afferent
- If volume / ECV drops, kidney is compromised as cannot respond
- Drop in GFR
Who is at greatest risk for postrenal failure?
- Older men with prostate disease
- Solitary kidney
- Intra abdominal pelvic cancer
What is post renal intervention sequelae?
- Post obstructive diuresis > 4L / day
- Lose ability to concentrate urine - Hyper K / Cl RTA that can become chronic
How do diagnose postrenal failure?
- Physical exam: dullness to percusion in superpubic area, fullness / discomfort here
- Easier in skinny ptn.
- Urge to urinate when push in area - Increased post void residual volume: ultrasound
- Hard to tell with ascites
Two types of ATN?
- Ischemic
- Nephrotoxic
* *Sepsis surgery and toxic exposures can cause
Two types of AIN?
- Drug associated
2. Non drug associated
Vascular causes of intrinsic renal failure?
- Malignant Htn.
- HUS / TTP
- Vasculitis
Definition of malignant HTN?
- BP > 180 / 120
- Evidence of end organ damage must be occurring
What is hypertensive urgency?
High BP but not yet any sign of end organ injury
Two general types of glomerular diseases?
- Nephritic: Inflammatory, sedimentation, blood, casts
2. Nephrotic: Proteinuria
Main causes of drug related acute interstitial nephritis?
Medications:
- PPIs
- NSAIDs
- Antimicrobials
Classic triad of Acute interstitial nephritis?
- Fever
- Rash
- Peripheral eosinophilia: urine too
