Nephrology Flashcards
This is secreted by the kidneys and promotes productions of the protein Angiotensin I
Renin converts angiotensin into angiotensin I
and angiotensin converting enzyme AKA ACE converts angiotensin I into angiotensin II
The active form of vitamin D that is produced by the kidneys
1,25-Dihydroxycholecalciferol
Blood seen on dipstick but no red cells on urinalysis: explanation?
Hemolysis or rhabdo (which produces myoglobin) in urine to test positive for blood on dipstic
This is the protein that is tested in a urine dip when looking at protein
Albumin
A notable protein that will not be tested with urine dipstick
Bence-jones protein is not tested by dip stick, if you are working up a patient for MM do not be encouraged by negative protein on dip stick
Interstitial nephritis is commonly tested on boards. you commonly see WBCs and no bacteria on urinalysis. What type of white blood cell is commonly elevated in these cases?
Eosinophils
Knee jerk: Red blood cell casts
Glomerulonephritis
Knee jerk: brown muddy casts
Acute tubular necrosis
Knee jerk: WBC casts
Pyelonephritis
four factors that are used to calculate the modern “eGFR” as determined by the MDRD equation displayed in most hospitals
Serum creatinine
age
sex
X1.2 if african american (more muscle mass on average)
186 * serum creatinine - (1.154age) - (0.203-.742 if female) * (1.1212 if african american)
eGFR as determined by the MDRD equation will ______ (under or over estimate) eGFR if a patient is obese
The Modification of Diet in Renal Disease (MDRD) and Chronic Kidney Disease and Epidemiology (CKD-EPI) equations do not include total weight but have been reported to also overestimate GFR in obese patients
(the AAFP board review course archive has this backwards! oops…)
Basically, these patient will produce more creatinine which is multiplied by 186 in the MDRD equation.
(Michels WM, Grootendorst DC, Verduijn M, Elliott EG, Dekker FW, Krediet RT: Performance of the Cockcroft-Gault, MDRD, and new CKD-EPI formulas in relation to GFR, age, and body size. Clin J Am Soc Nephrol 5: 1003–1009, 2010)
this measurment is often less effective at measuring true GFR than the MDRD equation but is more useful with dosing medications as it takes weight into account
Creatinine clearance
via the cockcroft-gault equasion
cutoff for nephrotic range proteinuria on 24 hour collection
> 3 grams
minimal criteria for AKI
increase in creatinine greater or equal to 0.3 in 48 hours
increase greater or equal to 1.5 times baseline in 7 days
And the one I never remember the numbers:
urine volume <0.5mL/kg/hr for more than 6 hours
most common cause of AKI in an adult?
- Stones
- Diuretic induced volume loss
- ATN
- Acute interstitial nephritis
- ATN!
45% of AKIs are ATN which includes hypotension and sepsis! as well as surgery, burns, nephrotoxins, ischemia
21% prerenal 13% acute on chronic kidney disease 10% obstruction including stones and BPH 4% glomerulonephritis 2% interstitial nephritis 1% thromboembolic disease
What does MPGN stand for
Membranoproliferative glomerularnephritis, a type of nephritic syndrome
Knee jerk: Fever, Rash, urine eosinophils after starting a new medication
Acute interstitial nephritis. Treatment is get rid of drug. Consult neph for +/- steroids if its bad