Transcript ARF.ppsx

Presented by:
Haya M. Al-Malaq
Outlines
• Part I – Lab Evaluation of RF.
• Part II – AG induced ATN.
• Part III – Amphoteracin B induced nephrotoxicity.
• Part IV – Post-renal ARF.
2
Renal Failure
Definition
• It is an abrupt decline in glomerular and tubular function,
resulting in the failure of the kidneys to excrete nitrogenous
waste products & to maintain fluid & electrolyte homeostasis.
• Increase in > 50% over baseline Cr & GFR <10mL/min, or
<25% of normal
• Azotemia is a consistent feature of acute renal failure (ARF),
oliguria (UOP <400-500 mL/d) is not.
• Anuria i.e. UOP < 0.5 ml/kg/h
3
Renal Failure
History & Physical Examination
• Shows the cause of ARF.
• Is the patient on any medications.
• A thorough physical examination in used conjunction with the
history can be invaluable in confirming the cause of ARF.
4
Renal Failure
Applied Therapeutic Chapter 31 Page 5
GFR
GFR:
Normal GFR: 100 ml/min/1.72m2
6
Renal Failure
Glomerular Filtration Rate (GFR)
• The total kidney GFR is equal to the sum of the filtration rate
of all the functioning nephrones and represent the total
functional mass of the kidney.
• It is a reliable index that can be used to evaluate the
progression of renal disease.
• Markers that are freely filtered at the glomerulus are best
indicator for accurate measurement of GFR (ideally should be
inert, freely filtered without secretion, reabsorption
metabolism or production by tubules)
7
Renal Failure
BUN
• BUN is produced by the liver, transported in the blood,
excreted by the kidneys.
• The conc. of BUN reflects KF b/c it is completely filtered,
reabsorbed & secreted.
• ARF, CRF r the common cause of elevated BUN.
• Normal BUN level (8-18 mg/dl or 3.0-6.5 mmol/l).
8
Renal Failure
BUN
• Do NOT quantify the extent of kidney dysfunction.
• Hi prot intake or catabolism, GI bleeding, hydration status,
terminal stage of liver disease all affect BUN level.
9
Renal Failure
Creatinine & Creatinine Clearance
• Most widely used clinical measurement of CLcr.
• Produced at a constant rate of non-enzymatic hydrolysis of muscle
stores.
• So individual muscle mass, age, sex are predictors of Cr production.
• It is freely filtered & about 10-20 % secreted.
• Cimetidine & trimethoprim inhibit Cr secretion & so increase SrCr
with out affecting GFR.
10
Renal Failure
Determination of CLcr by Cockcroft-Gult
Equation
CLcr =
(140 – Age) (IBW)
(72) (SrCr in mg/dl)
* 0.85 in females
Male IBW= 50 + ( 2.3 * height > 60 inches )
Female IBW= 45 (2.3 * height > 60 inches )
11
Renal Failure
Limitation of this method is that it produce falsely high CLcr in
the early stages of ARF & falsely low CLcr when ARF is
resolving.
CG is also in accurate in patients that have low muscle mass as
elderly, obese, or cachectic.
12
Renal Failure
Determination of CLcr by 24 Hour Urine
Collection
CLcr (ml/min) =
Uv (ml) * Ucr (mg/dl)
0.5 (SrCr1 + SrCr2)
SrCr1(mg/dl)= at the beginning of urine collection
SrCr2 (mg/dl)= at the end of urine collection
13
Renal Failure
Limitation of this method is that the accuracy of the calculation
depends on the accuracy of the urine collection process.
14
Renal Failure
Applied Therapeutic Chapter 31 Page 14
Case
• H.H is a 43 yo 80 kg man being treated for G-ve septic shock.
• HPI:
• He was admitted to the hospital 6 days ago but he has spent
the last 3 days intubated in the medical respiratory ICU b/c of
hypotension, respiratory failure and altered mental status.
• Hospital course:
• Since admission he has received ceftriaxone 2g/d, gentamycin
140 mg IV q8hrs.
16
Renal Failure
Case
•
•
•
•
Admission labs:
BUN 13 mg/dl (8-18)
SrCr 0.9 mg/dl (0.5-1.2)
WBC 23,500 cells/mm3 (4000-9000) with left shift (90%
PMN & 12% Bands)
• Serial bl & urine & sputum culture were +ve for Acinetobacter
Baumanii sensitive to ceftriaxone & gentamycin.
• In addition to the previous antibiotics current medications
include norepinephrine IV 18 g/min, pancuronium 0.02 mg/kg
IV q3hrs, famotidine 20 mg IV q12hrs, lorazepam IV 2mg/hr.
17
Renal Failure
Case
• H.H VS include T 38.6 oC; BP 90/40 mmHg; P 135 beats/min;
RR 20 breaths/min
•
•
•
•
•
18
New Labs:
BUN 65
SrCr 5.4
WBC 16,500 with left shift.
Over the last 2 days the urine output started to decline & today
is 700 ml/24 hrs (1,500-2,500).
Renal Failure
Case
•
•
•
•
•
•
•
•
19
Urine analysis & electrolytes:
Na 55 mEq/L (20-40)
Cr 26 mg/dl (50-100)
Many WBC (0-5)
3% RBCs casts (0-1%)
Granular casts (-ve)
Osmolality 250 mOsm/kg (400-600)
Sr genta Cp 15 mg/dl (6-10), Ct 9.1 mg/dl (<2)
Renal Failure
Case
• Given the history and lab data what is the source of HH ARF?
• How does AG induced ATN presents & what is the MOA?
• Is extended interval AG dosing less nephrotoxic than multiple
daily dosing?
20
Renal Failure
Applied Therapeutic Chapter 31 Page 15
Case
• H.H remained febrile for the next several days despite being
covered by broad spectrum AB.
• His gentamycin & ceftriaxone were stoped 3 days ago &
imipenem 500mg IV q12hrs was started.
• Today he is febrile 39 oC, blood fungal culture optained 5
days ago was positive for candida tropicalis sensitive only to
Ampho B.
• Labs : BUN 75; SrCr 6.1; WBC 17,500 , UOP 600 ml/day *
3d
22
Renal Failure
Case
• Are there any concerns with administration of Ampho B to
H.H if he still remains in ATN?
• How do lipid based Ampho B products reduces
nephrotoxicity?
23
Renal Failure
Applied Therapeutic Chapter 31 Page 16
Classification
25
Renal Failure
Causes & Symptoms
• Obstruction of urine flow by stone, malignancy (prostate,
cervix), prostatic hypertrophy, bilateral ureter stricture and
bladder outlet obstruction (as in prostatic hypertrophy).
• Onset of S & S are gradual; presents as decreased force of
urine stream, dribbling, or polyurea.
• Drugs my ply a role in crystal formation so should be included
in the differential diagnosis.
26
Renal Failure
Nephrolithiasis
• Common with genetic
predisposition.
•
•
•
•
•
•
27
Risk factors:
Low urine volume.
Hypercalciuria.
Hyperoxaluria.
Hyperuricosuria.
Chronic hi or lo urine PH.
• Types:
• Calcium stones (70-80%).
• Struvite (Mg Al ph, 2-20%,
can result in irreversible
kidney damage).
• Uric acid (chemotherapy
pts).
• Crystal (rare herditory
disorder).
Renal Failure
Presentation & Treatment
• TA is a 48yo man, ER
• Cc: sharp pain radiating to the groin, dysuria, hematouria,*4hr
similar to a previous episode of Ca nephrolithiasis.
• HPI:
• On questioning he admits that he had not been drinking much
fluids over the past wk owing to a busy work schedule and his
urine volume has been markedly lower than usual.
28
Renal Failure
Presentation & Treatment
•
•
•
•
Labs:
BUN 34 mg/dl (5-20)
SrCr 1.5 mg/dl (0.5-1.2)
Urine sampled showed large amount of Ca oxalate crystals
which indicates that the pt passed a kidney stone.
• What Sub & obj data suggest nephrolithiasis and how to
prevent this from occurring in the future?
• Can drugs crystallize the urine & cause ARF?
29
Renal Failure