Renal Diseases (Exam III-Mordekai) Flashcards
1
Q
Which vertebrae are the kidney’s typically situated between?
A
T12 - L4
2
Q
Which kidney is slightly more inferior/caudal? Why?
A
Right kidney is more inferior to accommodate the liver.
3
Q
What stimulates erythropoietin release from the kidneys?
A
Inadequate O₂ to the kidneys
4
Q
How much of CO do the kidneys receive?
A
20 - 22% ( 1-1.25L/min)
5
Q
What is Azotemia?
What causes it?
A
- Abnormally high levels of nitrogen containing compounds in the blood such as urea and creatinine.
- Azotemia is causes by dysfunctional kidneys.
6
Q
Where are your osmolality sensors located?
What occurs when you have hyperosmolality?
A
- Anterior Hypothalamus
- Hypothalamus signals pituitary gland to stimulate thirst and secrete ADH.
7
Q
What degree of hyponatremia would give you pause for surgery?
A
Less than 125 mg/dL
8
Q
6 listed here, theres alot more though
What are some conditions (discussed in lecture) that can cause hyponatremia?
A
- Prolonged diuretic use
- SIADH
- Acute or chronic renal failure
- Vomiting/diarrhea
- Insufficient aldosterone
- Excessive H₂O intake
9
Q
5 treatments. Na+ correction should not exceed?
How would hyponatremia be treated?
A
This is highly dependent on underlying pathology.
- Treatment of underlying disease
- NS
- Hypertonic Saline- 80ml/15 hours
- Lasix
- Mannitol
Na+ correction should not exceed 1.5meq/L/Hr
10
Q
What pathology could occur with rapid over-correction of hyponatremia?
A
Osmotic Demyelination Syndrome (“Locked-in Syndrome”)
11
Q
At what degree of hypernatremia would you typically cancel surgery?
A
155 mg/dL or greater
12
Q
7 listed
What are common causes of hypernatremia?
A
- Insufficient replacement of water loss
- Excessive sweating
- DI
- Gi losses
- Overcorrection of hyponatremia
- Poor oral intake
- too much bicarb
13
Q
What is the complication from rapid correction of hypernatremia?
A
There is little evidence of morbidity from rapid hypernatremia correction. 0.5 mmol/L/hr to an absolute change of 10 mmol/L/day would be best to avoid cerebral edema, seizures, and other neurological sequelae.
14
Q
Severe hyponatremia/hypernatremia both result in what?
A
Seizures, coma, and death
15
Q
What are normal levels of serum potassium?
A
3.5 - 5 mg/dL
16
Q
Excessive intake of what food is known to cause hypokalemia?
A
Licorice
17
Q
When does hypokalemia need to be treated with K⁺ repletion?
A
Serum K⁺ < 3 mg/dL
18
Q
What types of symptoms are generally seen with hypokalemia?
A
Cardiac & neuromuscular
19
Q
What EKG sign is seen with hypokalemia?
A
“U”-waves
20
Q
What other lab(s) needs to be check when replenishing K⁺ ?
A
Serum Phosphorus and Mg⁺⁺
21
Q
A patient presents with a gun shot wound to the thorax necessitating exploratory thoracostomy. The patient’s serum K⁺ level is 5.7 mg/dL, what do you do?
A
- Emergent surgery so proceed and treat the hyperkalemia
If the surgery was not emergent you would treat the K⁺ til it was below 5 mg/dL.
22
Q
What are hyperkalemia’s effects on on EKG?
What about on the cardiac cellular membrane?
A
- Peaked “T” Waves
- ↑ Vᵣₘ and ↓ APD (action potential duration)
- HYPERkalemia HYPOpolarizes the cell membrane
23
Q
CH BIG K
What is the treatment for hyperkalemia?
Avoid what?
A
“CH BIG K”
- Calcium gluconate (1° treatment)
- Hyperventilation
- Bicarbonate
- Insulin
- Glucose
- Kayexelate
Avoid succs, LR & K containing fluids
24
Q
Best measure of what?
What is a normal GFR?
A
- 125 - 140 mL/min
- Best measure of renal function overtime
25
# Correlates w/? Influenced by?
What is normal serum creatinine?
| Double serum creatinine causes what change to GFR?
* 0.6 - 1.2 mg/dL
* Correlates w/ muscle mass
* Can be influenced by high protein diet, supplements, muscle breakdown --> having a baseline is critical
* Double serum creatinine can decrease GFR by 50% acutely
26
What is better for acute monitoring of renal function, GFR or creatinine?
- Creatinine for acute monitoring
- GFR for chronic/trending
27
What populations would have lower creatinine levels?
Who would have higher?
- ↓ in women and elderly
- ↑ in body builders
28
What is the normal BUN:Creatinine ratio?
10:1
29
What is normal urine specific gravity?
1.001 - 1.035
30
# Affected by? High vs low?
What is normal BUN?
* 10- 20 mg/dL
* Affected by diet and intravascular volume
* low= malnourished or fluid overload
* high= dry, high protein diet
31
Large amounts of what macromolecule would be suggestive of glomerular injury?
protein
32
What is the primary metabolite of protein metabolism in the liver?
Urea
*Amino acids → ammonia → urea*
33
Which of these two compounds is subject to filtration at the glomerulus?
- Creatinine
- Urea
Trick question. Both are subject to filtration
34
Which of these two compounds is subject to reabsorption in the nephron?
- Creatinine
- Urea
Urea is reabsorbed unlike creatinine ( and therefore can't be used to measure GFR)
35
What would a BUN:Creatinine ratio of greater than 20:1 indicate?
Pre-renal Azotemia
36
What is normal urine output in adults?
1 mL/kg/hr
37
Your pre-operative patient has had less than 500 mLs of urine output in the past 24 hours. How would you classify this patient?
Oliguric
38
What's the greatest risk factor for AKI?
Pre-existing renal disease
39
# Four
What lab values would be indicative of acute kidney injury?
- Serum creatinine increase by > 0.3 mg/dL w/in 48hrs
- Serum creatinine increase by 50% w/in 7 days
- 50% decrease in creatinine clearance
- Oliguria (although not always seen)
40
# And treatment? If untreated?
What is the most common cause of pre-renal AKI?
Renal Hypoperfusion
*shock, burns, trauma, blood loss, aortic clamping, etc.*
Tx by restoring renal blood flow
If untreated --> renal azotemia
41
# Other lab values we would see?
What is a typical BUN:Creatinine ratio in intra-renal AKI?
* < 15:1
* Decreased urea reabsorption in proximal tubule--> decreased BUN
* Low creatinine clearance, high serum creatinine
* Low GFR --> late sx
42
Why are urea levels (in the urine) higher in intra-renal AKI?
Whole nephron is failing so **urea is not being reabsorbed in the PCT.**
43
What is the cause of intra-renal AKI?
Renal parenchymal (inner kidney) damage
*ATN, glomerulonephritis, CKD, etc.*
44
What is the cause of post-renal azotemia?
Urinary tract blockage
45
What BUN:Creatinine ratio is typically seen in post-renal AKI?
- Initial: > 15:1
- Chronic = ↓ BUN:Cr
46
What is the most common neurological complication of AKI?
Uremic Encephalopathy
47
# 4
What are the most common cardiac complications of AKI?
1. Volume Overload → Heart Failure / Pulmonary Edema
2. Electrolyte Imbalances → Arrhythmias
3. Uremia → Pericarditis
4. Hypertension --> Can worsen LV hypertrophy
48
# Two major complications
What are the most common hematologic complications of AKI?
* Anemia
- Due to decreased EPO & hemodilution
-
* The relationship between vWF and platelets is disrupted by uremia --> Uremic toxins interfere with platelet glycoprotein receptors that are needed for vWF-mediated adhesion and aggregation.
49
# 5
What are the most common metabolic complications of AKI?
- **Hyperkalemia**
- H₂O & Na⁺ retention
- ↓ albumin
- Metabolic acidosis
- Hyperparathyroidsm (this is actually more commonly seen in CKD)
50
Benefit of Prophylactic Na+ bicarb in CKD patients?
* Decreases formation of free radicals
* Chronic acidosis can lead to tubulointerstitial injury and fibrosis, accelerating CKD progression.
51
What are the leading causes of ESRD?
- DM
- HTN
52
On average, GFR decreases by _____ per decade starting from age 20.
10 ml/min
53
It is usually helpful to assume that everyone with CKD also has this condition.
CAD
54
What drugs are often used to combat chronic kidney disease?
ACEi's and ARBs
55
How do ACEi's and ARBs help treat CKD?
- Decrease systemic & glomerular HTN
- Decrease proteinuria
- Decrease glomerular sclerosis
56
What antihypertensive drugs need to be held on the day of surgery to decrease the risk of intraoperative hypotension?
ACEi's & ARBs
57
Which populations are at a higher risk for silent MI?
Women and diabetics
58
# Which patient population is likely to be dyslipidemic?
What lab values reflect dyslipidemia?
- Triglycerides > 500
- LDL > 100
59
What are the indications for dialysis?
- Volume overload
- ↑K⁺
- Severe metabolic acidosis
- Symptomatic uremia
- Drug overdose
60
What is the most common adverse event associated with dialysis?
Hypotension
61
What is the leading cause of death in dialysis patients?
Infection
62
When would peritoneal dialysis be preferred to hemodialysis?
PD is preferred for patients who can't tolerate large fluid shifts (*CHF or unstable angina*)
63
What two things reduce the risk of pre-renal azotemia?
- Maintain MAP > 65mmHg
- Appropriate hydration
64
Excessive use of 0.9% NaCl leads to what condition?
Hyperchloremic metabolic acidosis
65
Which of the following fluids are associated with increased risk of renal injury?
- Crystalloids
- Colloids
- Starches
Starches
66
Treating oliguric AKI patients with diuretics helps improve their condition via diuresing toxic metabolic byproducts of the AKI. T/F?
False. Diuretics in a oliguric AKI can further the renal injury.
67
This drug maintains GFR and urine output better than norepinephrine and neosynephrine via preferential constriction of the efferent arteriole.
Vasopressin
68
How is idiopathic hypercalciuria treated?
Thiazide diuretics
69
Why might you want to do regional or GA with paraplegic patients undergoing bladder surgeries?
To avoid autonomic dysreflexia.
70
# Stored where? % bound to albumin? How does pH affect? Normal iCal?
Calcium
* 99% stored in bone, 1% in ECF
* 60% is bound to albumin and inactive
* Only iCal is considered physiologically active
-Normal: 1.2-1.38mmol/L
* Alkalosis --> ↑ Ca++ binding to albumin -->↓ Decreased iCal
* Acidosis --> ↓ Ca++ binding to albumin--> ↑ Increased iCal
71
# 3
Hormones that regulate Ca++
* PTH: Increase GI absorption, renal reabsorption, and regulates bone & plasma levels
* Vitamin D: Increases GI absorption of Ca++
* Calcitonin: Promotes storage of Ca++ in bone
72
Causes of Hypo/Hyper Ca++
**HypoCa++**
* Low PTH secretion; thyroid problem or complication of parathyroid surgery --> can lead to laryngospasm
* Low Mg++, Low Vit. D
* Renail failure
* MTP
**HyperCa++**
* Hyperparathyroid: Ca++ <11
* Cancer: Ca++ >13
73
Life-threatening symptom of hypoCa++
Post-parathyroidectomy-hypocalcemia induced laryngospasm
74
HyperMg++
* Very uncommon; due to overtreatment of pre-eclampsia/eclampsia or pheochromocytoma
tx w/ diuresis, IV Ca++, dialysis
75
Medullary Cortex vs Inner Medulla
**Medullary Cortex:**
* Outer layer
* Receives 85-90% of RBF
**Inner Layer:**
* Most vunerable for developing necrosis in response to HoTN
76
# Normal, filtered and not what? most reliable measure of?
Creatinine Clearance
* 110-140ml/min
* Creatinine freely filtered and not reabsorbed
* Most reliable measure of GFR
77
IVC Collapsibility Indicates...
>50% collapsibility indicates fluid deficit
78
Hallmark of AKI?
* Azotemia; buildup of nitrogenous products such as urea and creatinine
79
# 2 medical conditions and predisposed to what?
CKD Cardiovascular Effects
* Systeminc HTN
* Dyslipidemia
* Predisposed to MI
80
# Many anesthetics are what? Need to avoid what kind of metabolites?
Anesthesia & CKD
* Many anesthetics are lipid soluble and reabsorbed by renal tubular cells
* Give agents not dependent on renal elimination
* Avoid active metabolites
-Morphine
-Demerol
81
# Two conditions
CKD Hematologic Effects
* Anemia (Target Hgb 10)
* Platelet dysfunction
*
82
# K+? Dialysis needs to happen when?
Preoperative Concerns For Renal Disease
| Prophylaxis of what? Blood loss stimulates what?
* K+ <5.5 for elective sx
* Dialysis pts need to be dialyzed w/in 24 hours prior to surgery
* Aspiration prophylaxis
* Blood loss stimulates SNS, resulting in decreased renal blood flow
