A 72 y/o male with pulmonary fibrosis develops an aspergillis fungal infection i
ID: 3474087 • Letter: A
Question
A 72 y/o male with pulmonary fibrosis develops an aspergillis fungal infection in the lungs. His physician prescribes amphotericin B (1.25 mg/kg, IV) for 4 days, followed by oral dosing for 14 days. Because of the potential renal complications, blood and urine measurements were taken at prior to and 15 min following administration of amphotericin B:
Blood
Pretreatment
Post-treatment
Urine
Pretreatment
Post-treatment
Na+ (mEq/L)
142
139
Na+ (mEq/L)
110
260
K+ (mEq/L)
4.2
4.0
K+ (mEq/L)
80
225
Mg2+ (mg/dL)
1.7
1.4
Mg2+ (mg/day)
19
45
Ca2+ (mg/dL)
8.9
8.6
Ca2+ (mg/day)
105
101
HCO3 (mEq/L)
26
24
HCO3
1.7
1.6
Creatinine (mg/dl)
1.1
2.0
Creatinine (mg/dL)
92
88
PAH (mg/ml)
0.013
0.02
PAH (mg/ml)
5.5
4.9
Glucose (mg/dL)
85
94
Glucose
0
0
BUN (mg/dL)
14
43
Volume (ml/min)
1.38
1.15
pCO2 (mmHg)
40
38
Osmolarity (mOsm/L)
650
625
pH
7.39
7.39
pH
6.8
7.1
A) What is the GFR prior to and after treatment with amphotericin B? (3pts) Include calculations
B) What is the cause of the change in GFR? (2pts)
Blood
Pretreatment
Post-treatment
Urine
Pretreatment
Post-treatment
Na+ (mEq/L)
142
139
Na+ (mEq/L)
110
260
K+ (mEq/L)
4.2
4.0
K+ (mEq/L)
80
225
Mg2+ (mg/dL)
1.7
1.4
Mg2+ (mg/day)
19
45
Ca2+ (mg/dL)
8.9
8.6
Ca2+ (mg/day)
105
101
HCO3 (mEq/L)
26
24
HCO3
1.7
1.6
Creatinine (mg/dl)
1.1
2.0
Creatinine (mg/dL)
92
88
PAH (mg/ml)
0.013
0.02
PAH (mg/ml)
5.5
4.9
Glucose (mg/dL)
85
94
Glucose
0
0
BUN (mg/dL)
14
43
Volume (ml/min)
1.38
1.15
pCO2 (mmHg)
40
38
Osmolarity (mOsm/L)
650
625
pH
7.39
7.39
pH
6.8
7.1
Explanation / Answer
A.GFR is nothing but glomerular filteration rate which is assessed before and following amphotericin B administration.It is a process of 24 hour urine collection which was performed for sodium, potassium and magnesium determination.Pathalogic examination is done on kidneys.
Induction of amphitericin B has a significant decrease in GFR. 4 days after amphotericin B injection, the GFR was significantly higher in patient when compared with control.There was also no significant differences between the groups in sodium, potassium and magnesium urine excretion after amphotericin B injection.
If dosing for GFR is 50-80, standard loading dose for all levels of renal function will be GFR>70ml/min.By using standard dose GFR 50-60ml/min, it is calculated as GFR ×0.18 mg/kg.
Then calculation for GFR 56ml/min will be,
56× 0.18= 10mg/ kg.
Then, according to this peak is monitered.
B.The changes in systemic blood pressure would cause change in PGC and thus changes occurs in GFR.Decreased MAP is detected by arterial baroreceptors which further leads to activation of sympathetic nervous system and constriction of afferent arteriole and there by GFR is decreased.
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