General Flashcards
What is hypovolaemia?
Overall fluid deficit in the body
What are three general causes of hypovolaemia?
- Poor fluid intake
- Excessive fluid loss
- Third space loss of fluid
What is third space loss of fluid?
Where fluid remains in the body but has shifted from the intravascular space to another compartment within the body
What is hypervolaemia?
Excess of fluid in the body
What is hypervolaemia also known as?
Fluid overload
What are the symptoms of fluid overload?
- Rapid weight gain
- Pitting oedema in arms, legs and face
- Swelling in the abdomen
- SOB secondary to pulmonary oedema
- High BP
What are the early symptoms of hypovolaemia?
- Headache
- Fatigue
- Weakness
- Thirst
- Dizziness
- Sunken eyes
- Dry, less elastic skin
What are the more severe symptoms of hypovolaemia?
- Oliguria
- Cyanosis
- Abdominal and chest pain
- Hypotension
- Tachycardia
- Cold peripheries
- Altered mental status
- Weak, thready pulse
What is severe hypovolaemia also known as?
Hypovolaemic shock
What is normal urine output for an adult?
0.5-2ml/kg body weight per hour
Na concentration in mild hyponatraemia:
130mmol/L
Na concentration in moderate hyponatraemia:
125-129mmol/L
Na concentration in severe hyponatraemia:
<125mmol/L
What are the clinical features of hyponatraemia?
- Gait instability
- Falls
- Concentration and cognitive defects
- Nausea
- Vomiting
- Headache
- Confusion
- Reduced consciousness
- Seizures
- Cardiorespiratory arrest
What is the biggest danger in hyponatraemia?
Cerebral oedema
What are the potential causes of hyponatraemia if the urinary Na is >30mmol/L?
- SIADH
- AVP (ADH)-like drugs
- Salt-wasting
- Vomiting
- Hypoadrenalism
- Cerebral salt-wasting
What is SIADH?
Syndrome of inappropriate ADH secretion (SIADH) is characterised by hyponatraemia secondary to the dilutional effects of excessive water retention.
What are the potential causes of hyponatraemia if the urinary Na is <30mmol/L?
- Heart failure
- Portal hypertension
- Nephrotic syndrome
- Hypoalbuminaemia
- Third space loss
- GI loss (D&V)
- Previous diuretic use
In mild-moderate hyponatraemia you treat with _____ _________.
Fluid restriction
What is the management of severe hyponatraemia?
1) Give hypertonic saline with close monitoring and serial blood tests
2) After a 5mmol/L rise stop infusion and treat according to the underlying diagnosis
Na concentration in hypernatraemia:
> 145mmol/L
If urine osmolality < plasma osmolality look for ________ ________.
Diabetes insipidius
What are the causes of low volume hypernatraemia?
- Sweating
- Vomiting
- Diarrhoea
- Diuretics
- Kidney disease
What are some causes of normal volume hypernatraemia?
- Fever
- Extreme thirst
- Diabetes insipidus
- Lithium
What are some causes of high volume hypernatraemia?
- Hyperaldosteronism
- Excessive IV saline
What are the ECG changes seen in hyperkalaemia?
- Tall-tented T waves
- Small P waves
- Widened QRS leading to a sinusoidal pattern and asystole
What are the causes of hyperkalaemia?
- AKI
- Metabolic acidosis
- Addison’s disease
- Rhabdomyolysis
- Massive blood transfusion
- Burns or other severe injuries
- Poorly controlled diabetes
What drugs can cause hyperkalaemia?
- Beta blockers
- K sparing diuretics
- ACE inhibitors
- Angiotensin II receptor blockers
- Spironolactone
- Ciclosponrin
- Heparin
What are the symptoms of chronic hyperkalaemia?
- Muscle weakness
- Numbness
- Tingling
- Nausea
What are the symptoms of acute-onset hyperkalaemia?
- Heart palpitations
- Dyspnoea
- Chest pain
- Nausea/vomiting
K concentration in hyperkalaemia:
> 5.5mmol/L
At what levels does hyperkalaemia become an emergency?
Greater than 6.5mmol/L
What is the treatment for hyperkalaemia in patients with ECG changes?` Why are they used?
IV calcium salts to stabilise the resting cardiac membrane potential.
How can hyperkalaemia be treated?
- IV calcium salts
- IV insulin combined with an infusion of glucose
- Nebulised β-2 adrenoceptor agonists can augment the effects of the insulin and glucose
Why does hyperkalaemia tend to be associated with acidosis?
Because as K levels rise fewer hydrogen ions can enter the cell.
Mild hypokalaemia levels are:
<3.5mmol/L
Sever hypokalaemia levels are:
<2.5mmol/L
What are the symptoms of mild hypokalaemia?
- Hypertension
- Abnormal heart rhythm
What are the symptoms of severe hypokalaemia?
- Muscle weakness
- Myalgia
- Tremor
- Muscle cramps
- Constipation
- Flaccid paralysis
- Hyporeflexia (absence of reflexes)
What are the causes of hypokalaemia?
- Diarrhoea
- Excessive perspiration
- Vomiting
- Pancreatic fistulae
- Adenoma
- Drugs
- Diabetic ketoacidosis
- Polyuria
- Magnesium deficiency
- Primary hyperaldosteronism (Conn’s syndrome)
- Cushing’s syndrome
- Renal tubular acidosis
What medications cause hypokalaemia?
- Loop diuretics
- Thiazide diuretics
- Amphotericin B
- Cisplatin
- Acetazolamide
What is the management of hypokalaemia?
- Correct any other underlying electrolyte abnormalities such as magnesium deficiency
- Administer KCL in NaCl solution at a maximum rate of 20mmol/hour
What are the likely causes of hypokalaemia when seen with metabolic alkalosis?
- Vomiting
- Thiazide and loop diuretics
- Cushing’s syndrome
- Conn’s syndrome (primary hyperaldosteronism)
What are the likely causes of hypokalaemia when seen with metabolic acidosis?
- Diarrhoea
- Renal tubular acidosis
- Acetazolamide
- Partially treated diabetic ketoacidosis
What are the likely causes of hypokalaemia when seen with hypertension?
- Cushing’s syndrome
- Conn’s syndrome (primary hyperaldosteronism)
- Liddle’s syndrome
- 11-beta hydroxylase deficiency*
What are the likely causes of hypokalaemia when seen with hypotension?
- Diuretics
- GI loss (e.g. Diarrhoea, vomiting)
- Renal tubular acidosis (type 1 and 2)
- Bartter’s syndrome
- Gitelman syndrome
What are the ECG features of hypokalaemia?
- U waves
- Small or absent T waves (occasionally inversion)
- Prolonged PR interval
- ST depression
- Long QT
Rhyme to remember ECG changes in hypokalaemia:
In hypokalaemia, U have no Pot and no T, but a long PR and a long QT
