Electrolyte Abnormalities Flashcards
1
Q
What is K normally excreted for
A
Exchange for Na
2
Q
What is a fatal level of K
Sequelae [4]
A
> 7
Cause fatal arrhythmias - asystole / VF / cardiac arrest
3
Q
What can cause hyperkalaemia? [3]
A
Decreased excretion
Increased release of intracellular K
Endocrine
4
Q
What causes decreased excretion? [4]
A
Renal failure - AKI or CKD
ACEI / ARB
NSAID
Spironolactone (K sparing diuretic)
5
Q
What causes increased K out of cells? [4]
A
Tumour lysis
Rhabdomyolysis
Metabolic acidosis
BB
6
Q
What are endocrine causes?
A
Addison’s (hypo adrenal)
- Increased K as decreased excretion
- Low Na as decreased reabsorption
- Low BP as low Na
7
Q
What are other causes? Hyperkalaemia
A
Massive blood transfusion
Type 4 renal tubular acidosis seen with DM or CKD
8
Q
What are symptoms of hyperkalaemia? [3]
A
Weakness, Dizzy
Fast irregular pulse
Chest pain, SOB, palpitations
9
Q
What do you need if symptomatic [2]
A
U+E
Urgent dialysis / haemofiltration
10
Q
How do you investigate [4]
A
DRABC
Bloods - U+E
ABG / VBG for K - repeat
ECG for arrhythmia
11
Q
What does ECG show [5]
A
Sinus brady or slow AF Tall tented T waves P wave widens then disappears Broad QRS AV block
12
Q
What should you do if haemodynamically unstable
A
Dialysis
Haemofiltration
13
Q
When do you treat [2]
A
K >6.5
ECG + K>6
14
Q
How do you treat [4]
A
Stop cause / drugs
Calcium gluconate / chloride
Insulin dextrose
Salbutamol
15
Q
What dose calcium gluconate
A
10% 10 mls IV injection
16
Q
What does calcium gluconate do
A
Stabilise myocardium if ECG changes
Gives 30-60 minute protection
17
Q
What dose of insulin dextrose
A
50ml 50%10 units insulin dextrose
Then infusion
18
Q
What does insulin do
A
Shift K internally
Dextrose counteract sugar loss
Must monitor for hypo
19
Q
What dose of salbutamol
A
5-10mg neb
Tachy can limit use
20
Q
What can you use if K not that high [2]
A
Calcium resonium
Used more in CKD to bring down over a few days
21
Q
What do you do if this fails [2]
A
Dialysis / anion exchange
Need to cure cause by getting patient to diuresis potassium out of body
22
Q
Why are diuretics not really used
A
Hypovolaemia
DO NOT use unless overloaded as well
23
Q
How do you prevent [3]
A
Low K
Stop ARB / spironolactone
Treat underlying cause
24
Q
How do you treat renal tubule acidosis [2]
A
HCO3
Fludrocortisone
25
What is emergency hypokalaemia
<2.5
26
What is most common causes of hypokalaemia (usually associated alkalosis but can be due to acidosis) [3]
D+V
Diuretic
Incorrect IV fluid replacement
27
What causes increased loss [4]
Diuretic
D+V
Laxatives
Pyloric stenosis
28
What are endocrine causes [2]
Cushing's
| Conn's
29
What are other causes [7] hypokalemia
```
Alkalosis
Insulin / salbutamol excess
Steroid use
Type 1 and 2 renal tubular acidosis
Tubular defect - Barter
Mg deficiency
Hypokalamic periodic paralysis
```
30
What are the symptoms of hypokalaemia [6]
```
Weakness, Cramps
Hypotonia, Hyporeflexia
Tetany
Palpitations
Light headed
Constipation
```
31
What does hypokalaemia predispose you too [2]
Digoxin toxicity
| Careful if on diuretic
32
What does ECG show? [4] hypokalemia
U wave
Prolonged QT and PR
ST depression
Absent T
33
What will urine potassium show
If renal loss = high
| If extra renal e.g. D+V then low
34
What should you do if renal loss
BP
35
If BP high
Endocrine
Renin-angiotensin ratio
Measure cortisol / creatinine
36
If BP normal
HCO3 levels
37
Acidosis
Tubular acidosis
38
Alkalosis
Tubular defect
| Diuretic
39
How do you treat [5] hypokalemia
```
Correct cause
Oral K if mild
IV K if severe
Monitor in cardiac area
Consider K sparing diuretic
```
40
When would you not give K [2]
If oligouria
| Or as fast bolus - no more than >20mmol / hour
41
What is best indication of long standing low K on diuretic
HCO3
42
What is most common cause of hypernatraemia [4]
| Other causes [3]
Water loss > Na loss
Dehydration
Fluid loss with no replacement - D+V / burns
Incorrect IV fluids
Others:
- DI - decreased ADH so increased water loss
- Osmotic diuresis in diabetic coma
- Primary aldosteronism as increased reabsorption
43
What are symptoms of hypernatraemia [6]
```
Lethargy, Irritable
Weakness
Thirst, Dehydration
Confusion
Coma
Seizure
```
44
What is important in bloods [4]
Increased Na
Increased albumin
Increased urea
Urine osmolarity
45
What else should you do
Water deficit calculator to work out
46
What will dehydration have
High urine osmolality as trying to conserve water
47
What will DI have
Low osmolarity
48
How do you treat hypernatraemia [2]
Oral rehydration
Glucose 5% slow IV guided by output and plasma Na
0.9% saline if hypovolaemia
49
What should you avoid
Hypertonic
50
What do you need to do with regards to fluid and how fast do you go and why [3]
Replace deficiency
Replace ongoing loss and insensible
Replace slowly no > than 0m5 as risk of cerebral oedema (seizure / coma / death)
51
When would you suspect primary aldosteronism [3]
K down
BP up
Alkalosis
52
What does dehydration always have [2]
High Na
| Not the same as hypovolemia
53
What is most common
Hyponatraemia <130mmol
| Either water excess or sodium depletion
54
What is important with regards to hyponatraemia? [2]
FLUID STATUS
Doesn't mean Na depletion
Can just be overloaded so dilutes
55
What causes hypovolaemic (dehydrated) hyponatraemia ? [4]
Urine Na >20
Diuretic
Addison's
Renal failure
Osmolar diuresis -hyperglycaemia
56
What causes hypovolaemic (Dehydrated) but urine Na <20 so lost other than kidney as kidney tried to hold on to Na / osmolarity high
```
D+V
Fistula
Burn, Trauma
Obstruction - 3rd space loss
CF
Heat in extra sport = ongoing ADH release
```
57
What can D+V cause
Low or high Na
58
What drugs should you consider stopping in hyponatremia [4]
Diuretic
SSRI
PPI - omeprazole
ACEI
59
What causes hypervolaemic hyponatraemia - diluted NA [5]
```
Nephrotic
HF
Liver cirrhosis
Renal failure
Polydipsia
```
60
What causes euvolaemic hyponatremia [3]
SIADH
Severe hypothyroid
Glucose-corticoid insufficiency
61
What suggests SIADH
High urine osmolality
| Think known cancer
62
What are symptoms of hyponatremia [6]
```
Confusion, Headache
Anorexia
Nausea
Malaise, Irritable
Weakness, CNS distubrance
Seizure, Encephalopathy
```
63
What is a medical emergency
Rapid changes or acute
64
How should you investigate [3]
Fluid balance
Urine osmolarity
Serum osmolarity
65
What are baseline bloods for cause of hyponatremia [7]
```
Glucose
Lipids
TFT
LFT
Cortisol for Addison
Urine Na+K
Urine osmolality
```
66
How do you test for Addison [2]
Cortisol low
| Short synacthen
67
How do you treat hyponatraemia [2]
Correct cause
| Replace Na and water at same rate
68
What do you do for asymptomatic and chronic hyponatremia [4]
Fluid restriction
ADH antagonist
Diuretic
Hypertonic saline
69
What do you do for acute severe symptomatic [4]
Cautious rehydration
Hypertonic 3% saline or Hartman
150ml over 15 min
Repeat if no improvement
70
What should you not do
Correct more than 10mmol/l in 24 hours
71
When would you consider furosemide
Not hypovolaemic
72
If hypovolaemic
0.9% saline
73
If hypervolaemic [2]
Treat cause- CF / liver /r renal
| Have fluid intake < output if oedema / SIADH / renal failure
74
What do you do if seizure or coma [2]
Hypertonic (1.8%) saline + furosemide
| Aim for gradual increase to 125
75
What may happen if Na corrected rapid [3]
HF
Central pontine myelinolysis
Osmotic demyelination syndrome
76
What does ADH antagonist do (Tolvaptan) [3]
Promote water excretion
No loss of electrolyte
Effective if hypervolaemic or euvolaemic but expensive
77
What can cause inappropriate ADH secretion
```
Tumour - SCLC / pancreas / gut
Empyema
CF
Pneumonia / TB
Drugs
CNS - meningitis / encephalitis / abscess / haemorrhage / stroke
Head trauma
```
78
How do you Dx
```
Assess fluid balance - euvolaemic
Hypotonic hyponatraemia
Urine osmolarity high - high urine Na
CXR
CT head
CAP
Bronchoscopy
```
79
What is Furst formula
Used to see if fluid restriction would be helpful in Rx
| <1 = restrict
80
How does metabolic acidosis cause hyperkalaemia
K and H ions fight to be exchanged for Na in distal tubule
81
What is hypokalaemia associated with [2]
Alkalosis
| So K loss
82
What can hypokalemia be associated with
Acidosis e.g. renal tubular
83
Symptoms of osmotic demyelination syndrome [6]
```
Dysthria
Dysphagia
Paresis
Seizure
Confusion
Coma
```
84
When should fluid intake be less than output in treatment of hyponatraemia [4]
Oedematous states
SIADH
Renal failure
Psychogenic polydipsia
85
Why should you replace fluid slowly in hypernatremia
Risk of cerebral oedema (seizure / coma) as brain loses electrolytes quickly whilst lowering of other electrolytes and water occurs more slowly
86
What causes hypo phosphate [6]
```
Alcohol
Acute liver failure
DKA
Refeeding
Primary hyperparathyroid
Osteomalacia
```
87
What are the consequences of hypophosphate [5]
```
RBC haemolysis
WBC / platelet dysfunction
Muscle weakness
Rhabdomyolysis
CNS dysfunction
```
88
What causes raised ALP physiological [3]
Growing child
Pregnancy
Healing fracture
89
What causes pathological raised [6]
```
Liver
Osteomalcia
Bone mets
Pagets
Renal failure
Hyperparathyroid
```
90
What causes high Ca [2]
Bone mets
| Hyperparathyroid
91
What causes with low Ca [2]
Osteomalacia
| Renal failure
92
What are causes of hypocalcaemia
```
Vit D deficiency (osteomalacia)
CKD
Renal failure
Hypoparathyroid (surgery / thyroiditis)
Pseudohypoparathyroid (insensitive)
Rehabdomyolysis
Mg deficiency
Massive blood transfusion
Acute pancreatitis
```
93
What is calcium needed for
Muscle and nerve function
94
What does hypoca cause [5]
```
Tetany
Parathesia
Increased QT
Trosseau
Chvostek's
```
95
What is tetany [3]
Twitching
Cramping
Spasm
96
If chronic hypoca[2]
Depression
| Cataracts
97
What is trousseau [2]
Carpal spasm when brachial artery occluded when BP cuff above systolic
Wrist flexion and fingers drawn in
98
What is Chvostek
Tapping facial nerve causes facial muscles to twitch
99
How do you treat hypoercalcaemia [3]
IV calcium gluconate 10ml 10% 10 minutes if severe
ECG
Treat cause
100
How do you treat hypercalcaemia [3]
Rehydration
Normal saline
3-4l per day
101
What can be used after [2]
Biphosphonates
| Calcitonin - works quicker
102
What do you give if caused by sarcoid
Steroids
103
What can be used but careful
Loop diuretics if can't tolerate fluid but may worsen other electrolyte imbalances
