RLE Flashcards
1
Q
What part of the nephron recovers the most sodium and water?
A
proximal tubule
2
Q
What common chemotherapeutic agents cause Fanconi syndrome?
A
ifosfamide, cisplatin
3
Q
Loop diuretics target which receptor?
A
Na-K-2Cl cotransporter
4
Q
Loop diuretics work in what part of the nephron?
A
Loop of Henle
5
Q
Is urine leaving Loop of Henle: hypotonic or hypertonic?
A
hypotonic
6
Q
Thiazide diuretics work at what receptor?
A
Na-Cl cotransporter
7
Q
What is the point of the countercurrent mechanism in the kidney?
A
Retain the ability to increase H2O reabsorption if needed
8
Q
What hormone regulates the ultimate concentration of urine?
A
ADH
9
Q
ADH controls the insertion of what channel?
A
aquaporin-2
10
Q
High ADH: collecting duct permeable or impermeable to water?
A
permeable
11
Q
Low ADH: collecting duct permeable or impermeable to water?
A
impermeable
12
Q
What site of the nephron is responsible for regulation of potassium?
A
collecting tubule
13
Q
What part of the nephron is the major site of magnesium reabsorption?
A
Loop of Henle
14
Q
What part of the nephron regulates urinary calcium excretion?
A
distal tubule
15
Q
Aldosterone-mediated effects occur in what part of the nephron?
A
collecting duct
16
Q
Acidification of the urine occurs in what part of the nephron?
A
collecting duct
17
Q
Tubular glomerular feedback mechanism involves increased detection of what ion by the macula densa?
A
increased chloride
18
Q
Tubular glomerular feedback results in vasoconstriction of what?
A
afferent arteriole
19
Q
2 main functions of the macula densa cells?
A
sense chloride (tubuloglomerular feedback) and mediate renin release from juxtaglomerular cells
20
Q
Renin is released by what cells?
A
juxtaglomerular cells
21
Q
What does renin do?
A
catalyzes angiotensinogen into angiotensin I
22
Q
What does ACE do?
A
catalyzes angiotensin I to angiotensin II
23
Q
What does angiotensin II do to the renal arterioles?
A
efferent > afferent vasoconstriction (maintains GFR)
24
Q
RPF (renal plasma flow) =
A
RPF = (renal arterial pressure - renal venous pressure)/renal vascular resistance
25
FF (filtration fraction) =
FF = GFR/RPF
26
Aldosterone release is stimulated by what hormone?
angiotensin II
27
Units of renal clearance?
volume per time
28
Prostaglandins vasodilate what part of the nephron?
afferent arteriole
29
Why do NSAIDs cause AKI?
inhibit prostaglandins, which vasodilate afferent arteriole (NSAIDs cause unopposed vasoconstriction of afferent arteriole)
30
Creatinine clearance: overestimates or underestimates GFR?
overestimates (some secretion)
31
What medication can be given to inhibit creatinine secretion, so that creatinine clearance is more accurate of GFR?
cimetidine (H2 blocker)
32
Urea clearance: overestimate or underestimate GFR?
underestimates (some reabsorbed)
33
Normal plasma osmolality?
275-290 mOsm/kg
34
Regulation of osmolality occurs primarily via what hormone?
ADH
35
The serum sodium concentration is usually reflective of what?
water balance
36
Aldosterone is synthesized where?
zona glomerulosa (adrenal gland)
37
Effect of aldosterone in distal nephron?
reabsorb Na/Cl (restore volume), secrete K/H
38
Aldosterone works in what cells of the nephron?
principal cells (cortical collecting tubule)
39
What is the main determinant of ADH secretion?
serum osmolality
40
ADH effect via V1 receptor?
vasoconstriction, prostaglandin release (negative feedback)
41
ADH effect via V2 receptor?
aquaporin-2 insertion (collecting duct)
42
V2 ADH receptors mediate release of what clotting factors?
factor 8 and vWF
43
Prostaglandins are derived from the metabolism of what molecule?
arachidonic acid
44
What enzyme catalyzes the production of prostaglandins from arachidonic acid?
cyclooxygenase
45
Prostaglandin effect on renin?
increases renin secretion
46
Aldosterone effect on potassium?
decreases (enhances secretion)
47
Loop diuretics effect on calcium?
increase calcium excretion
48
Loop diuretics effect on potassium?
decrease (increased aldosterone and increased distal flow rate)
49
Thiazide diuretic effect on calcium?
increase reabsorption
50
Spironolactone mechanism of action?
aldosterone receptor antagonist
51
Which part of the nephron is most susceptible to ischemic damage?
medullary thick ascending limb and proximal tubule (S3 segment)
52
In the early proximal tubule, ammonia (NH3) is formed from what?
glutamine
53
NH3 is?
ammonia
54
NH4 is?
ammonium
55
Hyperkalemia leads to what effect on acid secretion?
decreased acid secretion
56
Type 1 RTA is also called what?
distal RTA
57
Mechanism of distal RTA?
H+ secretion impaired
58
What common medication can cause acquired distal RTA?
amphotericin
59
Type 2 RTA is also called what?
proximal RTA
60
Proximal RTA mechanism?
Inability to reabsorb bicarbonate
61
Type 4 RTA mechanism?
aldosterone resistance
62
Which RTA is usually associated with hyperkalemia?
type 4 (aldosterone resistance)
63
Which RTA requires a LOT of bicarbonate to restore acid/base balance?
proximal RTA
64
What is the Na concentration of 0.9% normal saline?
154
65
What is the Na concentration of plasmalyte?
140
66
What is the Na concentration of LR?
130
67
To distinguish nephrogenic from central diabetes insipidus, order what test?
copeptin (surrogate for ADH)
68
Hypernatremia - Free water deficit =
Free water deficit (mL) = 4 mL x kg x [Na change]
69
To correct a 3L free water deficit, how much 0.45% NaCl would be required?
6L (1/2 NS is 50% free water)
70
Na falls by how much for every 100 mg/dL rise in glucose above normal?
Na falls by 1.6 mEq/L
71
Glucocorticoid effect on AVP/ADH?
inhibitory (glucocorticoid deficiency has markedly elevated AVP/ADH)
72
What is another name for AVP?
ADH
73
Vaptan diuretics mechanism of action?
V2 antagonists (inhibit ADH)
74
The diuresis from Vaptans: hypotonic or hypertonic urine?
hypotonic (free water diuresis)
75
Consider giving 25% albumin replacement if albumin is below what value?
<2.0
76
Acidosis should not be treated with bicarbonate until what is normalized?
calcium
77
What is the best oral agent for calcium repletion?
calcium glubionate
78
What common medication causes hypomagnesemia?
amphotericin B
79
Potassium rises how much for every 0.1 unit fall in pH?
potassium rises 0.6 mEq/L
80
Hyperkalemia: decreases or increases resting potential?
decreases (facilitating depolarization)
81
What is the first EKG finding of hyperkalemia?
peaked T waves
82
What EKG lead is most consistently changed in hyperkalemia?
lead II
83
What is the most abundant intracellular anion?
phosphate
84
The normal anion gap is reflective primarily of what negatively charged particle?
albumin
85
Urine anion gap =
urine anion gap = (Na + K) - Cl
86
What does a negative urine anion gap indicate?
NH4+ excretion (appropriate response to acidosis)
87
Modified Schwartz formula for eGFR =
eGFR = (0.413 x Ht)/Creatinine
88
How many stages of AKI are in KDIGO definition?
3 stages (1, 2, 3)
89
Which KDIGO AKI stage is UOP <0.5 mL/kg/hr for 6-12h?
stage 1
90
Which KDIGO AKI stage is UOP <0.5 mL/kg/hr for >12h?
stage 2
91
Which KDIGO AKI stage is Cr increase by 0.3 (or 150-200%)?
stage 1
92
Which KDIGO AKI stage is Cr increase by 200-300%?
stage 2
93
What is the most common cause of AKI in neonates?
congenital heart disease
94
What is the most common cause of AKI in children <5?
ischemic insults
95
What is the most common cause of AKI in children >5 and adolescents?
nephrotoxic agents
96
What region of the nephron is most susceptible to AKI?
S3 segment of medulla
97
What type of AKI: increased FeNa?
intrinsic (hypoxia causes Na-K pump to translocate to opposite membrane, so Na reabsorption decreased)
98
Tumor lysis syndrome causes precipitation of what in the kidneys?
uric acid and calcium phosphate
99
What medication causes a marked reduction in uric acid (for use in tumor lysis syndrome)?
Rasburicase
100
Rasburicase mechanism?
recombinant form of the enzyme urate oxidase (catalyzes uric acid)
101
Allopurinol mechanism?
inhibits xanthine oxidase (inhibits formation of uric acid)
102
Definition of isosthenuria?
Inability to concentrate or dilute the urine
103
Isosthenuria is seen in what type of kidney injury?
ATN
104
What type of AKI: decreased FeNa?
pre-renal
105
What is the FeUrea in a pre-renal injury?
<35%
106
What is the FeUrea in an intrinsic injury?
>50%
107
Insensible fluid losses - composition?
essentially electrolyte-free
108
Mechanism of action of theophylline in AKI?
intrarenal vasodilation via adenosine receptor antagonism
109
Standard HD vs high-efficiency HD: which removes higher-molecular weight products better?
high-efficiency HD
110
What part of the RRT prescription should change if there is risk of dialysis disequilibrium?
Lower blood flow rate (normally 5 mL/kg/min)
111
Extracorporeal blood volume (ie, CRRT prime) should not exceed what percent of total blood volume?
10%
112
Need to use blood prime for CRRT if the circuit volume exceeds what percent of total blood volume?
10%
113
Total blood volume =
70 mL/kg (80 mL/kg in infants)
114
CVVH stands for what?
continuous veno-veno hemofiltration
115
CVVHD stands for what?
continuous veno-veno hemodialysis
116
CVVHDF stands for what?
continuous veno-veno hemodiafiltration
117
CVVH: convection or diffusion?
convection
118
CVVHD: convection or diffusion?
diffusion
119
CVVHDF: convection or diffusion?
both
120
Convection in CRRT works how?
replacement fluid added, creates "solvent drag" across pressure gradient ("french press")
121
Diffusion in CRRT works how?
dialysate added, diffuses down concentration gradient ("tea bag")
122
Large molecular weight solutes (eg, Vancomycin) are cleared better by convection or diffusion?
convection
123
A sieving coefficient of 1 reflects what?
complete permeability
124
A sieving coefficient of 0 reflects what?
complete impermeability
125
A higher sieving coefficient means better or worse clearance?
better
126
What are Kupffer cells?
liver macrophages
127
What are Stellate cells?
liver prefibroblasts
128
What is the most common metabolic cause of ALF in children >5 years?
Wilson disease
129
Wilson disease is caused by what?
copper transport defect (accumulated copper)
130
What disease is associated with Kayser-Fleischer rings?
Wilson disease
131
What type of mushroom can cause ALF?
amanita species (amatoxin)
132
What coagulation factor can differentiate DIC from liver failure?
Factor VIII (low in DIC, normal in ALF)
133
Detection of hepatic recovery can be monitored by measuring the rise of what?
AFP (alpha fetoprotein)
134
What is usually biopsied to detect iron deposition?
salivary glands
135
To prevent toxic hyperammonemia, what organ increases production of glutamine?
skeletal muscle
136
Ammonia complexes with glutamine to form what?
glutamate
137
What compound is increased to counter hyperammonemia?
glutamine
138
What opioid is good for liver failure and why?
Remifentanil (metabolized by esterases)
139
What is indicated in patients with an abnormal PT/INR in ALF?
vitamin K
140
Consider giving FFP to a patient with ALF if their INR is what?
>7 (otherwise correcting mild-moderately elevated could cause procoagulant profile)
141
What grade of HE? Changes in behavior, altered sleep
grade I
142
What grade of HE? spatiotemporal disorientation, inappropriate behavior, asterixis
grade II
143
What grade of HE? marked confusion, stupor, absent asterixis
grade III
144
What grade of HE? comatose
grade IV
145
What common antimicrobial agents can cause acute adrenal insufficiency?
fluconazole, ketoconazole
146
What are the presenting lab values in CAH?
hyponatremia, hyperkalemia, metabolic acidosis
147
How is CAH diagnosed?
Elevated 17-hydroxyprogesterone
148
Which is the active thyroid hormone: T3 or T4?
T3
149
Peripheral conversion of thyroid hormone: T4 to T3 or T3 to T4?
T4 to T3
150
Methimazole mechanism of action?
Prevents T4 to T3 conversion
151
Which drug is liver toxic: Methimazole or PTU?
PTU
152
First line therapy for hyperthyroidism?
Methimazole
153
Mechanism of iodine for treatment of hyperthyroidism?
Prevents release of thyroid hormone from thyroid
154
Euthyroid sick syndrome involves elevation of what thyroid hormone?
reverse T3 (rT3)
155
Why is magnesium deficiency related to hypocalcemia?
magnesium is required for PTH synthesis
156
What medication could be used in SIADH?
tolvaptan (vasopressin receptor antagonist)
157
Pheochromocytomas are associated with what diseases?
MEN2B, VHL (von Hippel-Lindau), NF-1
158
A cortisol level of what is indicative of adrenal insufficiency?
<5
159
Failure of the cortisol to raise (after ACTH stimulation) how much is indicative of adrenal insufficiency?
<18 (should rise more than 18)
160
If hypothyroidism and adrenal insufficiency coexist, which is treated first?
adrenal insufficiency (treating hypothyroidism first can precipitate an adrenal crisis; thyroid hormone may increase cortisol clearance)
161
How quickly do glycogen stores deplete when fasting?
4-6 hours
162
Hyperammonemia with respiratory alkalosis suggests what type of IEM?
urea cycle disorder
163
Hyperammonemia with metabolic acidosis suggests what type of IEM?
organic acidemia
164
Hypoglycemia with hyperketosis suggests what type of IEM?
organic acidemia
165
Hypoglycemia with hypoketosis suggests what type of IEM?
fatty acid oxidation disorder (or hyperinsulinemia)
166
What IEM may cause coagulopathy resulting in spontaneous intracranial hemorrhage mistaken for child abuse?
hypercholanemia (bile acid disorder)
167
Treatment (medications) of hyperammonemic encephalopathy?
Ammonul (nitrogen scavenger), arginine
168
What is Ammonul comprised of?
sodium phenylacetate/sodium benzoate
169
What level of hyperammonemia calls for HD?
>350
