CKD Stage I (Normal)

CKD Stage II (Normal)

CKD Stage III (GFR 30-60)

CKD Stage IV (GFR 15-30)

CKD Stage V - ESRD (GFR <15)

BUN/Cr ratio >20

Urine osmolality high

High specific gravity on urinalysis

Urine sodium <20

Fractional excretion of sodium (FENa) < 1%

What lab value is most commonly used to assess acute kidney injury?

What is the mortality rate of sepsis related acute kidney injury?

serum creatinine

70%

List the common causes of pre-renal failure.

A patient with ________ would be able to successfully donate their kidneys, as the organs would be fine after transplantation into a new patient?

Volume Depletion (hypo-perfusion) - diarrhea, poor intake, vomiting, diuretics

Renal Hypoperfusion from organ dysfunction - Heart and Liver failure

Systemic hypo-perfusion - peripheral dilation à Sepsis

Intra-Renal Vasoconstriction - Hepato-renal syndrome (hormonal imbalance)

kidney itself fine - body bad - transplant kidney and it works fine

Loss of Auto-regulatory Capacity - NSAID’s, ACE inhibitors, contrast

Define oliguria.

What type of imaging would be especially valuable for kidney assessment?

When is a kidney biopsy indicated for definitive diagnosis?

oliguria - excretion of <500cc/24hrs

renal ultrasound

Nephrotic syndrome

Greater than 3 grams protein

Positive serological work up

Rapidly Progressing renal failure

What are the two primary causes of chronic kidney disease?

Which disorders are typically nephritic vs. those that are nephrotic?

1. Diabetes

2. Hypertension

Nephritic: IgA Nephropathy, MPGN, Cryoglobulinemia, Systemic Lupus – proliferative, Anti – GBM, ANCA vasculitis, Post - Infectious

Nephrotic: Membranous Nephropathy, FSGS (focal segmental glomerulosclerosis), Minimal Change Disease (assume MCD with kids having proteinuria), Myeloma Kidney, Diabetes

A - refractory acidosis

E - severe electrolytes abnormalities (K)

I - intoxications (ethylene glycol)

O - refractory volume overload (CHF)

U - uremic complications (mental status)

intra-renal failure:

(observed value depends on etiology)

high in Acute Tubular Necrosis (ATN)

low in Glomerulonephritis (GN)

The fractional excretion of sodium (FE_Na) is the percentage of the sodium filtered by the kidney which is excreted in the urine. In clinical use, the fractional excretion of sodium can be calculated as part of the evaluation of acute renal failure in order to determine if hypovolemia or decreased effective circulating plasma volume is a contributor to the renal failure. Measurement of the urine sodium concentration provides information on the integrity of tubular reabsorptive function. Low urine sodium concentration thus indicates not only intact reabsorptive function but also the presence of a stimulus to conserve sodium.

FE_Na can be useful in the evaluation of acute renal failure and oliguria. Low fractional excretion indicate sodium retention by the kidney, suggesting pathophysiology extrinsic to the urinary system such as volume depletion or decrease effective circulating volume (e.g. low output heart failure). Higher values can suggest sodium wasting due to acute tubular necrosis or other causes of intrinsic renal failure. The FE_Na may be affected or invalidated by diuretic use, since many diuretics act by altering the kidney's handling of sodium.

Pre-renal failure (inflow)

Hypo-perfusion: Volume depletion, Cardiac failure, Sepsis (peripheral dilation), Renal vasoconstriction

Signs/Sx:

Volume depleted states-thirst, tachycardia, weight loss, low bp

Volume expanded states-crackles, JVD, edema, pulm. congestion

intrinsic renal failure (internal)

Acute Glomerulonephritis; Tubular damage (severe hypotension, myoglobin); Interstitial Nephritis (allergic, infectious, autoimmune); Vasculitis

Aberrant FeNa (high in ATN/low in GN) - Urine sodium is variable; U/A micro (RBC’s, casts, protein)

post-renal failure (outflow)

Obstruction (Stones, Hypertrophy of prostate, Cancer, Strictures/fibrosis); Papillary necrosis