SBA 300 Paper 5 Flashcards
- An asthmatic 40-year-old woman with myasthenia gravis (MG) presents for a
multi-level lumbar decompression. She was diagnosed with MG 8 years ago,
has difficulty with swallowing solids, and her current medication includes
pyridostigmine 720mg/day and her forced vital capacity (FVC) is 2.9 litres.
Which of the following is most likely to predict her requirement for a period of
postoperative ventilation?
A Bulbar symptoms
B Pyridostigmine use of 720mg/day
C FVC of 2.9 litres
D Duration of disease >6years
E Concurrent history of asthma
- D Duration of disease >6 years
Myasthenia gravis (MG) is an autoimmune disease with a prevalence between 1
in 10,000–100,000. Women are more likely to be affected with a female:male ratio
of 3:2. The disease is caused by IgG antibodies to the post-synaptic acetylcholine
(ACh) receptors at the neuromuscular junction of skeletal muscle. These receptors
are occupied by the antibodies and ultimately destroyed through complement-
mediated immune processes. MG is therefore associated with fatiguing muscle
weakness, as only a limited response to ACh released at the neuromuscular junction
is possible and any subsequent stimulation results in fewer and fewer receptors
available for activation.
The extent of muscle involvement and severity of disease was classified by Osserman
as seen in Table 5.2.15% of patients fall into Class I, the remaining 85% suffer from generalised MG.
Cardiac and smooth muscle is entirely unaffected.
An anaesthetic and surgery can impact on a patient withMG in a number of ways.
The physiological stress in itself can exacerbate symptoms and, for a patient who
may be unable to achieve adequate tidal volumes or cough ordinarily, lack of pre-
operative planning could prove fatal.
There are four recognised risk factors that are associated with an increased likelihood
of requiring a period of postoperative ventilation. - MG duration of >6 years – this has the greatest predictive value
- Concurrent history of chronic respiratory disease
- Pyridostigmine requirements of >750mg/day in the preceding 48 hours
- Forced vital capacity <2.9 litres
Other considerations for trying to predict the need for respiratory support include
surgery – type, length and need for intubation; anaesthetic – general +/– local, need
for muscle relaxation and perhaps reversal; medication – opiate use in a patient
with affected respiratory reserve, drugs such as aminoglycosides or beta-blockers
that can cause an exacerbation of MG and administration of the patient’s normal medication immediately post operatively, i.e. conversion of oral pyridostigmine to
intravenous equivalent doses (30mg orally = 1mg intravenously).
The factor most likely to predict this patient’s requirement for postoperative
ventilation is her duration ofMG of >6 years.
- You are anaesthetising a 68-year-old patient for bowel resection for sub-acute
obstruction. He had been vomiting intermittently for 3 days. After induction of
anaesthesia he became hypotensive so you commenced a noradrenaline infusion
which is currently running at 0.2µg/kg/min. A thoracic epidural has been sited but
only a test dose has been given so far. Blood pressure is 110/70 and capillary refill
time is 4 seconds. An oesophageal Doppler is in situ. Based on the waveform and data shown in Figure 5.1, what is the appropriate first
course of action?
A Increase the noradrenaline infusion
B Commence a dobutamine infusion
C Commence the epidural infusion and leave the noradrenaline
D Commence a GTN infusion and leave the noradrenaline
E Administer 250mL of Hartmann’s solution and decrease the noradrenaline
E Administer 250mL of Hartmann’s solution and decrease
the noradrenaline
The oesophageal Doppler is a minimally invasive cardiac output monitor. The
physical principle underlying the technology is the Doppler Effect, where the
changing frequency of ultrasound waves reflected from red blood cells as they pass
along the descending aorta is used to calculate the blood velocity. The Doppler
equation uses this frequency shift to estimate the velocity of red blood cells as they
pass the probe. By integrating this with time, and taking the area under the curve
(velocity vs time) the velocity time integral can be calculated (VTI). This is a measure
of stroke distance (Figure 5.2, distance=velocity x time). When multiplied by the
aortic cross sectional area the stroke distance gives the volume of blood passing the
probe in a given period of time. The aortic cross sectional area is usually estimated from a normogram based on the
patient’s age, weight and height (which are input by the operator at start up) but can
also be measured with transoesophageal echocardiography. It should be apparent
that not all of the blood ejected via the aortic valve travels in the descending aorta
so a correction factor is used to account for coronary, brachiocephalic, carotid
and subclavian flow to give a figure for stroke volume (SV). Cardiac output is then
calculated by multiplying SV by heart rate.
Correct positioning of the probe gives the characteristic waveform seen above.
Elements of the waveform can be used to indicate left ventricular contractility,stroke volume, preload and afterload. When interpreting data from the oesophageal
Doppler it is important to appreciate the interdependency of the variables.
Peak velocity
The speed at which blood is ejected from the left ventricle is proportional to
inotropy. It declines with age, with normal values for a 20-year-old being around
100 cm/s compared with around 30–60cm/s at the age of 90. The peak velocity
measurement in the patient in question is 22cm/s; almost certainly lower than
expected. As well as reflecting contractility, peak velocity (PV) is inversely related to
afterload for a given level of inotropy.
Stroke distance/stroke volume
Although stroke volume involves the use of an estimated aortic cross sectional area,
the values are almost certainly more familiar to most than those of stroke distance.
The patient in the question has a low stroke volume which should then prompt the
user to think about the causes of this - low preload, pump failure, dysrhythmia, high
afterload, and then to use the other information (both from the Doppler and clinical
sources) to guide treatment. The stroke volume calculated in this example is lower
than would be expected.
FTc = flow time corrected = systolic ejection time corrected for heart rate
This has been used as a measure of preload because the fuller the left ventricle is, the
longer it will contract. However, this assumes a given level of inotropy and afterload
and therefore is susceptible to changes in these variables, not just preload. Normal
FTc is 330-360 ms (based on the assumption that systole occupies around a third of
the cardiac cycle (corrected for a heart rate of 60, so a total cycle time of 1000ms = 1
s). In the patient described above, the FTc is 250 ms so is lower than expected.
Afterload
Changes in afterload will alter the width and peak of the waveform according to the
work undertaken by the left ventricle. An increase in afterload will result in shorter
FTc and lower PV whilst lowering afterload with reduce left ventricular work and
result in higher PV and longer FTc.
Any change in left ventricular dynamics will therefore lead to a change in the shape
of the waveform created (assuming other factors including aortic cross section and
regional blood flow are constant).
To summarise the data from the patient above, he has a good chance of
preoperative hypovolaemia, compounded by surgery and general anaesthesia and
has Doppler data suggestive of: low cardiac output, low stroke volume, low peak
velocity and low FTc.
The most likely clinical explanation for this is that the patient is being over-treated
with a vasoconstrictor (in this case noradrenaline) which is in turn masking
significant hypovolaemia; A is therefore not the correct option. The appropriate first step is therefore option E; to give a fluid bolus and assess response; an appropriate
Doppler response would be widening of the waveform and an increase in the area
under the curve (and so stroke volume). This may allow a reduction in the dose of
catecholamine which in turn will reduce afterload and improve myocardial oxygen
balance and contractility.
Although commencement of the epidural infusion is part of optimal perioperative
management, doing so before correction of hypovolaemia may lead to hypotension
and escalating noradrenaline requirements (a similar scenario may occur with GTN).
It should be noted that epidurals, and indeed anaesthetic agents, will alter the shape
of the Doppler waveform by lowering systemic vascular resistance and therefore
raising FTc, making the waveform appear wider.
Although cardiac index is low, in primary pump failure left ventricular end-diastolic
volume would be expected to increase leading to normal FTc. In addition, the
patient already has a tachycardia, which dobutamine may well exacerbate, and so
option B is not currently advisable.
- A patient in the cardiac intensive care unit suffers a cardiac arrest following three
vessel coronary artery bypass grafting. He has epicardial pacing wires with the box
set to DDD. The monitor shows pulseless electrical activity with pacing spikes.
Cardiopulmonary resuscitation (CPR) is commenced.
What is the most appropriate next step?
A 1mg adrenaline IV
B 300mg bolus of amiodarone
C Institution of external pacing
D Exclusion of a tension pneumothorax
E Turn off the pacemaker
E Turn off the pacemaker
Although the incidence of cardiac arrest post cardiac surgery is low (0.7–2.9%),
survival following an arrest is high, primarily due to a reversible cause often being
present. In up to 50% of cases ventricular fibrillation (VF) is the cause. A protocol
has been developed and published by the European Association for Cardiothoracic
Surgery. In the situation described above, the patient is being paced, so underlying
VF would not be immediately obvious.
Accordingly, the appropriate first step would be to cease pacing, check the
underlying rhythm and defibrillate as indicated. If 3 DC shocks are unsuccessful,
300mg amiodarone can be given whilst preparing for sternotomy.
If no dysrhythmia is present, attention should then turn to other reversible causes
such as tamponade, tension pneumothorax and haemorrhage. Asystole or severe
bradycardia would be treated with pacing (in this instance via the epicardial wires)
or atropine pending immediate sternotomy.
Concurrent management would include verification of endotracheal tube
placement, ventilation with 100% oxygen, CPR and further DC shocks every 2
minutes in the case of an ongoing shockable rhythm.
Immediate use of adrenaline, and especially doses of 1mg, followed by correction
of a reversible cause and restoration of cardiac output may lead to severe rebound
hypertension and consequent bleeding. Answer A would not be an appropriate first
step in this instance.
- A 70-year-old smoker with limited mouth opening having previously undergone
a neck dissection with adjuvant radiotherapy is scheduled for surgery to treat his
right middle lobe tumour. A difficult airway is anticipated and it is likely that post-
operative ventilatory support will be required.
Which of the following is the most appropriate airway management strategy?
A Fibreoptic intubation with a single-lumen tube and a right sided bronchial
blocker
B Fibreoptic intubation with a single lumen tube and a left sided bronchial
blocker
C Videolaryngoscopy and insertion of a left sided double-lumen tube
D Fibreoptic left sided endobronchial intubation with a single-lumen tube
E Awake tracheostomy and insertion of right sided double-lumen endobronchial
tracheostomy tube
A Fibreoptic intubation with a single-lumen tube and a
right sided bronchial blocker
Anaesthetists are often asked to isolate and selectively ventilate a single lung to
improve the surgical field. Lung isolation is achieved by collapsing the lung in the
operative hemithorax and can be achieved by the use of double lumen tubes,
bronchial blockers and endobronchial tubes. Familiarity with the advantages
and disadvantages of these different techniques is important, particularly when
presented with patients who are likely to have a difficult intubation and need post-
operative ventilation.
In the case above, the safest way to establish an appropriate airway is by performing
an awake oral or nasal fibreoptic intubation with a single lumen tube followed
by insertion of a right sided bronchial blocker to collapse the operative lung. A
bronchial blocker is a balloon tipped device which can be inserted down a single
lumen endotracheal tube and be placed under fibrescopic guidance into main
bronchi or lobar segments to cause distal lung deflation. Bronchial blockers can
be useful in patients with difficult airways when there is a plan to ventilate post-
operatively, since a potentially hazardous tube exchange at the end of the operation
is avoided. Compared to double lumen tubes however, bronchial blockers achieve
less reliable and slower lung deflation with an increased likelihood of intra-operative
dislodgement. The inflated balloon also prevents access to the deflated lung for
suctioning or oxygen delivery.
Double lumen tubes consist of a tracheal and an endobronchial tube attached to
one another in parallel thereby allowing isolation of either lung when correctly sited.
They are divided into right and left-sided tubes according to the orientation of the
endobronchial tube within the tracheobronchial tree. Since the right upper lobe
bronchus arises in closer proximity to the carina when compared to the left, there
is a higher risk of inadvertent upper lobe collapse when right sided tubes are used.
Advantages of double lumen tubes over bronchial blockers include the ability to
deflate and re-expand both lungs easily intra-operatively (Table 5.3). There is also
unimpeded access to either lung for bronchoscopy, suctioning and oxygen delivery.
Since double lumen tubes are large diameter and pre-shaped, they may be difficult
to site in patients with a limited mouth opening (case above) or with distorted lower
airway anatomyAn uncut single lumen tracheal tube can be advanced into a bronchus to isolate the
lungs in emergency situations such as an acute contralateral tension pneumothorax or
airway haemorrhage. For elective operations however, the use of double lumen tubes
or bronchial blockers are better choices for controlled lung isolation (Figure 5.3Rarely, patients may require lung isolation via a tracheostomy and double lumen
endobronchial tracheostomy tubes are available for this purpose. In the above
scenario where there has been previous surgery and radiotherapy to the neck, the
formation of a tracheostomy may be technically challenging.
- A 75-year-old man is to have a cystoscopy and bladder biopsy as a day surgery
case. He has a 40 pack year history of smoking. Recent spirometry has shown his
FEV1/FVC is 0.6, and echocardiography has shown an ejection fraction of 40%. He
has been consented for a spinal anaesthetic.
What is the most appropriate solution for the spinal injection?
A Hyperbaric bupivacaine 0.5% 2mL
B Hyperbaric bupivacaine 0.5% 2mL with 300µg diamorphine
C Plain bupivacaine 0.5% 2mL with 10µg fentanyl
D Hyperbaric prilocaine 2% 2mL with 10µg fentanyl
E Hyperbaric lignocaine 2% 2mL with 10µg fentanyl
- D Hyperbaric prilocaine 2% 2mL with 10µg fentanyl
A spinal anaesthetic in this patient with significant respiratory disease avoids the
need for airway manipulation and ventilation, with the risks of increased airway
reactivity, pneumothorax and postoperative respiratory compromise. Selective
spinal anaesthesia is a technique favoured in day surgery that describes a block
concentrated on the operative site and aims for a predominately sensory rather than
complete motor block. In higher risk day surgery patients it allows earlier recovery
and mobilisation and avoids the cardiovascular instability associated with more
extensive spreadThe ideal agent for such a block would:
t have a rapid onset
t provide a dense predictable sensory block
t have a short duration of action to allow early recovery and ambulation
t have a favourable side-effect and safety profile
Hyperbaric prilocaine 2% has been licensed for spinal use in the UK since 2010 and
is now widely accepted as the agent of choice for day surgery. It has both a rapid
onset and resolution of block and confers a higher degree of cardiovascular stability
compared to bupivacaine.
Low doses of hyperbaric bupivacaine can achieve selective blockade but doses
higher than 7mg are associated with urinary retention especially in those having
urology procedures and those older than 70 years. Plain solutions are slightly
hypobaric at 37oC and less predictable as they produce greater variability in spread,
so are less likely to result in a selective block.
Lignocaine has an early onset time and a short duration of action, but has been
associated with TNS (transient neurological symptoms – self-limiting pain and
dysaesthesia in the buttocks) especially after day surgery in the lithotomy position.
Fentanyl acts synergistically with the local anaesthetic allowing reduced dose and
prolonged analgesia. Using small doses (10–25µg) avoids respiratory depression and
is less likely to cause pruritus.
Before attempting to mobilise after a spinal anaesthetic, patients should have
return of perianal sensation, plantar flexion of the foot to pre-operative strength
and proprioception of the big toe, and discharged after voiding and other standard
criteria have been met.
- You are asked to review a confused 72-year-old man in recovery. He has had a
transurethral resection of his prostate for benign prostatic hyperplasia (BPH). A
brief assessment reveals him to be disorientated in time and place, and restless.
Whilst you review his anaesthetic chart he has a short seizure, which resolves
spontaneously.
After assessing his airway breathing and circulation, which of the following would
be the best immediate management:
A Administration 2mg of intravenous midazolam
B Starting an infusion of magnesium sulphate
C Sending an urgent U&Es, FBC and osmolality, and prepare intravenous
lorazepam in case of further seizure
D Administering 20–40mg of intravenous frusemide
E Infusing 1–2mL/kg 3% NaCl
- C Sending an urgent U&Es, FBC and osmolality, and
prepare intravenous lorazepam in case of further seizure
Transurethral resection of the prostate (TURP) is a common procedure, and the best
available treatment for benign prostatic hyperplasia (BPH) with obstructive lower urinary
tract symptoms. TURP syndrome is caused by the absorption of hypotonic irrigation
fluid. The quantity of absorbed fluid is important and the probability of developing TURP
syndrome increases with the following factors which all increase absorption:
t Length of resection, especially >1 hour
t Significant bleeding, implying large quantities of open vessels
t Bladder or prostatic capsular perforation, (fluid is rapidly absorbed from the
peritoneum)
t Height of the irrigation fluid bag. This corresponds to the hydrostatic pressure
within the bladder. Heights >70 cm are unusual
The syndrome is caused by changes in:Volume
This is biphasic in nature. Initially, the circulation absorbs large volumes and there
can be hypertension with a reflex bradycardia. This may also cause signs and
symptoms of volume overload with left sided heart failure and pulmonary oedema.
Later as the irrigation fluid shifts to the extracellular space (due to its hypotonic
composition), there may be a relative hypovolaemia and hypotension. It’s worth
bearing in mind that the first stage of hypertension is often masked by the low
systemic vascular resistance (SVR) state of a spinal sympathetic block.
Treatment of hypervolaemia resulting in left ventricular failure (LVF) involves
frusemide, but hypervolaemia without LVF is better treated with mannitol as this
lowers serum sodium less than frusemide. Hypotension and reduced heart rates are
addressed with vasoconstrictors, calcium and atropine.
Plasma sodium and osmolality
The hyponatraemia of TURP syndrome is mainly dilutional, and produces headaches,
nausea and vomiting, seizures and coma. However, of the two values, osmolality
is by far the more important. This is because rapid falls in osmolality cannot be
countered by pumps in neuronal cell walls, and the cells thus get flooded with water
down its osmotic gradient, leading to cerebral oedema and increased intracranial
pressure. If osmolality is relatively normal, low sodium does not need treatment in an
asymptomatic patient. Sodium should only be corrected slowly to prevent pontine
demyelination, and only correct until symptoms resolve, not to normal values.
Treatment of hyponatraemia should be titrated to symptoms, slowly, not >1mmol/L/
hour. Remember to measure the osmolality also. If the sodium is <120mmol/L, give
3% NaCl (weight in kg x 0.6 x 2 = number of mL 3% NaCl needed to elevate sodium
by 1mmol/L).
Glycine
Although glycine is an inhibitory neurotransmitter, it does have effects increasing
NMDA receptor activity. This can produce the phenomenon of dis-inhibition,
such that the first neurological symptoms may be of irritability and seizures. As
concentrations increase, coma may follow. Due to its physiological antagonist
action at NMDA receptors magnesium is a useful second line treatment for seizures
associated with TURP syndrome.
Treatment of seizures is supportive and if needed involves benzodiazepines such as
lorazepam and if required magnesium.
The first stems A and B suggest treatments primarily focussed on seizure control.
While the possibility of a further seizure should be at the forefront of one’s mind,
a self-terminating isolated seizure may not require treatment. Instead the focus
should be on identifying the severity of the condition and thus determining whether
specific treatment is required, as in stem C. Empirical treatment without knowing the
sodium or osmolarity first may be dangerous (E), and treatment with frusemide (D) is
reserved for heart failure secondary to fluid overload
- An obese 45-year-old woman with progressive conductive hearing loss secondary
to chronic suppurative otitis media is due to undergo tympanoplasty. During the
preoperative safety check list, the team is informed by the surgeon that intubation
and facial nerve monitoring is required.
Which of the following would be the most appropriate to use as part of your
anaesthetic technique?
A Remifentanil infusion
B Ketamine bolus
C Nitrous oxide
D Clonidine infusion
E Magnesium sulphate infusion
A Remifentanil infusion
The middle ear is a delicate air filled cavity containing three ossicles which transmit
sound vibrations from the eardrum to the cochlea. Due to its small size, location
and fragile content, the provision of anaesthesia for surgery to this unique site is
especially challenging.
Maintaining the surgical field is difficult since small amounts of bleeding or
movements can significantly degrade the view during microsurgery. Furthermore,
the use of neuromuscular blocking drugs to provide akinesia is frequently restricted
due to the need for intraoperative facial nerve monitoring. A smooth, cough-free
wake up is desirable to avoid compromising the surgical result, and patients are at
an increased risk of developing post-operative nausea and vomiting.
Remifentanil is the most appropriate drug to use in this scenario since it addresses a
number of problems associated with middle ear surgery anaesthesia in addition to
providing adequate intraoperative analgesia. To minimise blood loss, remifentanil
can be used to rapidly control the blood pressure to deliver safe hypotensive
anaesthesia and a stable pulse in suitable patients. Remifentanil also allows
mechanical ventilation without neuromuscular blocking agents which enables
uninterrupted facial nerve monitoring. Remifentanil also attenuates coughing on
emergence, and if used in conjunction with propofol as part of a total intravenous
anaesthetic, reduces the incidence of post-operative nausea and vomiting.
Ketamine produces intense analgesia and dissociative anaesthesia via NMDA
receptor antagonism at both spinal cord and central sites. It can however cause
hypertension due to an increased sympathetic outflow which can result in bleeding
into the surgical field. Another drawback is the risk of emergence delirium and
coughing due to hypersalivation after extubation. For these reasons, it is not the
most appropriate option.
Nitrous oxide produces analgesia by inducing endogenous opioid release centrally.
Unfortunately, since the relative solubility of nitrous oxide in blood is far greater than
that of nitrogen, it will diffuse into the middle ear cavity at a more rapid rate than
nitrogen can leave. Subsequent raised middle ear pressures can cause displacement
of tympanoplasty grafts and promote nausea and vomiting, making this option
inappropriate.
Clonidine is a central acting presynaptic α2 adrenoceptor agonist with numerous
effects which lend themselves favourably to anaesthesia for middle ear surgery.
Not only does clonidine provide intraoperative analgesia, but also a reduction in
sympathetic outflow and therefore hypotension to minimise blood loss. Its sedative
effects may also contribute to a smooth wake up. In contrast to remifentanil
however, clonidine does not obviate the need to administer neuromuscular blocking
drugs which will interfere with facial nerve monitoring.
Magnesium is a versatile drug also with many favourable pharmacodynamic
properties. As a result of its NMDA receptor antagonism, magnesium provides
analgesia. It also inhibits smooth muscle contraction and has a direct vasodilator
effect which causes hypotension. Magnesium does impede neuromuscular
transmission by inhibiting acetylcholine release at the pre-synaptic nerve terminal, but this is not enough on its own to cause paralysis and allow safe, controlled
ventilation.
- A 63-year-old man with a confirmed inherited pseudocholinesterase deficiency
(EuEa) is attending for his first course of electroconvulsive therapy.
Which of the following drug combinations is most appropriate for his induction of
anaesthesia?
A Propofol and mivacurium
B Propofol and rocuronium
C Propofol and alfentanil
D Thiopentone and rocuronium
E Thiopentone and alfentanil
B Propofol and rocuronium
The choice of anaesthetic agents for ECT depends on the ability to:
t provide rapid onset and recovery from unconsciousness
t provide adequate muscle relaxation to avoid injury from an uncontrolled tonic-
clonic seizure
t have minimal effect on the seizure duration or quality
The original gold standard was methohexital as it has minimal anticonvulsant
properties, rapid induction and recovery, and a wide therapeutic range. However, it
has now been replaced by newer hypnotic agents, and the widespread availability
of propofol, its good cardiovascular stability profile and quick emergence properties,
mean that it is the most commonly used agent. Low doses such as <1mg/kg are
used to avoid reducing duration of seizures. Etomidate may reduce seizure threshold
allowing lower currents to be used, but has a pronounced hyperdynamic response
and long emergence times. Thiopentone reduces the duration of seizures and
there is an increased arrhythmia risk. Inhalational induction with sevoflurane has
a reduced seizure duration compared to methohexital and is time consuming for
the anaesthetist. It is important that whichever agent is chosen, the same one is
used throughout the course of treatment to avoid influencing changes in seizure
threshold. Combining with opioids may reduce seizure duration but overall has an
induction agent sparing effect.
Muscle relaxants are essential in preventing uncontrolled convulsions and
musculoskeletal injury. Succinylcholine is still the most commonly used, typically a
dose of 0.5mg/kg.
Mivacurium is short acting and doses 0.15mg/kg should be used to control
muscle movements. Individuals with variations in the genes coding for the
pseudocholinesterase enzyme exhibit prolonged neuromuscular blockade. 4
alleles are described depending on the degree of enzyme inhibition; normal (Eu),
atypical or dibucaine resistance (Ea), fluoride resistant (Es) and silent (Es). 96% of
the population is homozygotes for the normal gene. Homozygotes for the atypical
or silent gene exhibit prolonged paralysis for up to 4 hours and homozygotes for
the fluoride resistant up to 2 hours. Heterozygotes exhibit mild prolonged paralysis
up to 10 minutes. Both suxamethonium and mivacurium are contraindicated in
cases of pseudocholinesterase deficiency, even in heterozygotes with intermediate
dibucaine numbers. Rocuronium or vecuronium are the most appropriate
alternatives, in view of the increasing availability of sugammadex.
- A 70-year old man is scheduled for foot surgery under general anaesthesia and a
sciatic nerve block. There are no ultrasound machines available and you decide on
a landmark technique to perform the block.
Which one of the following described techniques results in the most proximal
approach to performing a sciatic nerve block?
A Mansour’s approach
B Raj’s approach
C Labat’s approach
D Beck’s approach
E Guardini’s approach
A Mansour’s approach
○ The merger of the anterior rami of spinal nerves L4, L5, S1, S2, S3 and S4 forms the sacral
plexus.
○ This plexus provides sensory and motor innervation to the posterior thigh, most
of the lower leg and the foot.
○ The two most important branches for the lower limb
surgery are the sciatic nerve and the posterior femoral cutaneous nerve of the thigh.
○ The sciatic nerve is derived from the ventral rami of L4–S3 and is the longest and widest nerve in the body. It supplies the posterior thigh and almost the entire lower
limb below the knee. It exits the pelvis through the greater sciatic notch below the
piriformis muscle to enter the lower limb between the ischial tuberosity and the
greater trochanter. The sciatic nerve then descends in the posterior thigh toward the popliteal fossa where it runs posterolateral to the popliteal vessels in the upper part of the fossa.
○ The sciatic nerve is actually a mixture of two nerves from its origin (tibial and common peroneal nerves). In the pelvis, the two nerves are packed together by
connective tissues to form the sciatic nerve. At the proximal pole of the popliteal
fossa, the sciatic nerve divides into its component nerves. Sometimes, the two
components separate early at the upper thigh or even in the pelvis.
○ The posterior femoral cutaneous nerve (PFCN) is found in the pelvis from the anterior rami of S1, S2 and S3. This is purely a sensory nerve and it descends with
the sciatic nerve in the upper part of the thigh. It gives off the inferior cluneal nerve (sensation to the lower buttock), perineal branches (sensation to the external genitalia), and femoral and sural branches (sensation to the back of the thigh and calf). It ends in the popliteal fossa where it anastomoses with the sural nerve.
The most common indications for sciatic nerve block are anaesthesia and
postoperative analgesia for foot and ankle surgery. It is also useful for operations above the knee, and for management of chronic pain conditions in the lower limbs such as sciatic neuropathy.
Various approaches have been described to block the sciatic nerve because of its
deep location and the difficulties associated with positioning.
● Mansour’s parasacral block:
Mansour describes this block in 1993.
• It is the most proximal approach to sciatic nerve and mainly used to provide analgesia following major ankle and foot surgeries. It is more than an isolated sciatic nerve block
because it may block the entire sacral plexus, and this is advantageous for knee and above the knee operations when compared with distal sciatic nerve approaches. It
reliably blocks the two components of sciatic nerve and the PFCN.
The patient is positioned in the lateral decubitus position and a line is drawn connecting the posterior superior iliac spine (PSIS) and the ischial tuberosity. The
point of insertion is 6 cm caudal from PSIS along this line. A 100mm insulated block needle is used because the nerve is deep in this area. The motor response is
inversion and planter flexion (tibial) or dorsiflexion and eversion (peroneal) that can be elicited at a depth of 7–9 cm.
● Labat’s transgluteal approach:
This is a posterior approach to the sciatic nerve (Figure 5.4). The patient is positioned in Sims’ position (lateral decubitus with a slight
forward tilt) with the operative side up and hip flexed. Three lines are drawn. Line 1 is
connecting the PSIS and the greater trochanter (GT), line 2 is extended from the GT
to the sacral hiatus and line 3 is dropped perpendicularly from the midpoint of line 1
to intersect line 2. The needle entry point is where line 3 and line 2 meet. A 100mm
22G block needle is used and inserted perpendicular to all planes. The sciatic motor
response is usually observed at around 5–8 cm depth.
● Raj approach (lithotomy subgloteal): This has the advantages of supine approach to the sciatic nerve and easy landmarks. The patient is posited in a
supine position with both hip and knee flexed. A line is drawn extending from
the greater trochanter and the ischial tuberosity. The sciatic nerve twitches are
elicited by inserting a 100 mm 22G block needle perpendicularly at the line midpoint. (Figure 5.5)
● Beck’s anterior approach:
This approach to a sciatic nerve block has the advantage
of maintaining the patient in the supine position and the lower limb in the neutral
position. A longer needle (150 mm) is needed because the nerve is deep to the
adductors. Three lines are drawn: line 1 connects the anterior superior iliac spine and
the pubic tubercle, line 2 is parallel to line 1 but drawn from the greater trochanter, and line 3 is dropped perpendicularly from the junction of the medial and the
middle thirds of line 1 to intersect line 2. The needle insertion point is where line 3
intersects line 2. This block is technically challenging and requires a deep insertion of
the needle, hence can be a painful block to perform awake (Figure 5.5).
● Guardini’s subtrochanteric approach:
This block uses a lateral approach to the
sciatic nerve with a supine position and neutral lower limb. The point of entry is 4 cm
distal and 2 cm inferior to the greater trochanter. A 100mm 22G needle is used to
perform this block. It is not a common approach because it is technically difficult to
perform and may be painful (Figure 5.6).
● Popliteal approach: this is the most common approach to sciatic nerve because the
nerve is superficial and easy to find either by a peripheral nerve stimulator (PNS) or
ultrasound (US) technique (Figure 5.6).
There are two approaches to PNS guided popliteal block: posterior and lateral. Posterior approach: with the patient prone, a triangle is drawn in the popliteal fossa.
The popliteal crease forms the base, the biceps femoris tendon forms the lateral
border and semimembranosus tendon forms the medial border. A line is drawn
connecting the apex to the midpoint of the base. The needle entry point is 1cm
lateral to this midline and around 7–9cm above the skin crease (base). A 50mm 22G
block needle is used for this block and 25–40mL of local anaesthetic may be used.
In most people, the sciatic nerve divides into tibial and common peroneal nerves
near the apex of the popliteal fossa (8–10cm above the crease). However, in some
patients, as previously mentioned, the nerve separates more proximally. Therefore,
multi-stimulation or US-guided technique is advocated for a successful block.
Lateral approach: with the patient supine and the hip flexed to 30 degrees and the
groove between the vastus lateralis and biceps femoris is palpated. A 100mm 22G
block needle is inserted perpendicularly about 7–9cm above the popliteal fossa
crease. The common peroneal nerve is stimulated in this approach.
Ultrasound guided popliteal nerve block: a linear high frequency US probe is
placed parallel to the popliteal fossa crease. Then the probe is moved proximally
until the popliteal artery pulsation is seen. The sciatic nerve (or its two components)
is generally located lateral and superficial to the popliteal artery. The best place to
inject local anaesthetic is just before the division of the sciatic nerve. This can be
obtained by tracing the two components upwards until a single nerve is seen.
- A 68-year old man with emphysema is listed for elbow surgery under regional
anaesthesia.
Which of the following would be the most appropriate nerve block for this patient?
A Interscalene brachial plexus block
B Supraclavicular brachial plexus block
C Medial infraclavicular brachial plexus block
D Axillary brachial plexus block
E Mid-arm peripheral nerve block
- D Axillary brachial plexus block
Patients undergoing upper limb surgery have several options of anaesthesia,
including local, regional and general anaesthesia. Brachial plexus block represents
the most common use of nerve blocks in current regional anaesthetic practice.
There are different approaches to block the brachial plexus. According to the site of
the surgery they are divided into two groups: blocks above the clavicle (interscalene
and supraclavicular) and blocks below the clavicle (infraclavicular and axillary).
Interscalene blocks are mainly indicated for shoulder and upper arm surgery. This
approach targets the upper roots (C5-C7) and, because of the vertical arrangement
of the brachial plexus roots in the interscalene groove, C8 and T1 nerve roots are
missed, hence the ulnar nerve may not be blocked. Therefore, this approach is
unreliable for hand and forearm surgery. Because the phrenic nerve runs anterior
to the anterior scalene muscle, local anaesthetic injection at this level will almost
always lead to a phrenic nerve blockade and may present a significant problem in
patients with respiratory compromise, while the rare but important side effect of
pneumothorax is also a possibility. The interscalene approach to a brachial plexus
block is therefore is unsuitable in this clinical scenario.
Supraclavicular blocks are performed at the level where the brachial plexus trunks
are in close proximity to each other so the entire upper limb is blocked reliably.
The usual indications of this block are arm and hand surgery, but it can also be
used for shoulder surgery if a suprascapular block is performed separately. Ulnar
sparing might be a problem with the supraclavicular approach because of the
medial location of the inferior trunk in this area; however the use of ultrasound
might overcome this problem. The incidence of pneumothorax in supraclavicular
blocks is high due to the proximity of the brachial plexus to the dome of the pleura
at this level. However, the risk of pneumothorax can be reduced with a modified
approach and the use of ultrasound. This block may present a danger for patients
with respiratory problems such as emphysema, hence should be avoided unless
performed by anaesthetists with extensive skill in this technique.
Infraclavicular blocks are performed at the level of the cords of the brachial plexus
(See Figure 4.1). It blocks each of the three cords of the brachial plexus and therefore
it anesthetises the entire arm successfully. It is a simple block to perform without
the aid of ultrasound; however, the infraclavicular approach to brachial plexus block
is not popular because of the fairly high failure rate and the risk of pneumothorax.
The use of ultrasound significantly improves the success rate of this block but is
remains a difficult procedure to perform. This block is not suitable for patients with
respiratory compromise, again due to the high pneumothorax risk, particularly with
a medial infraclavicular approach.
The safest and the most commonly used and studied brachial plexus approach is
the axillary block. It has few side-effects and usually covers the entire upper limb with the exception of the lateral part of the arm and the forearm, which requires
additional musculocutaneous nerve block. This approach blocks the brachial
plexus terminal branches and depends on the relationship of nerves to the axillary
vessels. It is usually performed for elbow, arm and hand surgery. With no risk of
pneumothorax and phrenic nerve block, the axillary block is the most suitable
brachial plexus approach for patients with respiratory problems and lung diseases,
and is therefore the most appropriate choice of block in this scenario.
Radial, ulnar and median nerves can all be easily blocked in the arm as well.
However, the duration of the regional anaesthesia tends to be shorter than with
brachial plexus blocks. It is also limited by the requirement to block several nerves
and the application tourniquet for most surgery. Therefore, this mid-arm peripheral
nerve block is not the optimal option to consider in this clinical scenario.
- You have been called to assist in the care of a 17-year-old girl who has become
increasingly agitated in the emergency department. She has a history of mental
illness and has recently been behaving strangely. Now her actions are violent and
compromising her safety and that of those around her. You are unable to assess her
formally, and she has not had any blood tests, intravenous access or observations.
Security officers are present, and the emergency department registrar tells you
he would like to perform bloods, a CT head and a lumbar puncture. The plan has
been approved by the girl’s mother and the paediatric consultant.
How will you proceed?
A Use security staff to hold the patient, insert intravenous access, and give 2mg
midazolam and 2µg/kg fentanyl in the room
B Use security staff to hold the patient, and give intramuscular 4mg/kg
ketamine, then transfer to the resuscitation bay
C Do nothing, and refuse to get involved with this case
D Encourage her to take 20mg oral temazepam and review
E Using security staff to hold the patient, transfer to theatre, and perform an
inhalational induction with sevoflurane
- B Use security staff to hold the patient, and give 4mg/kg
ketamine intramuscularly, then transfer to rhesus
The usual tenets of sedation applicable in the elective situation are not necessarily
appropriate in the emergency setting. The important issues here are consent,
holding/restraint as well as the provision of safe sedation.
Consent
At the age of 17 the patient is legally still a child. If she were able to demonstrate
maturity and understanding and be judged to be Gillick competent, she would be
able to give her consent. When it comes to refusing treatment the child may not do
this in the same way, even if competent. A parent may still be able to consent for the
child in this case. In the case of a parent refusing treatment on behalf of their child,
(which the medical team believe is indicated), an interim care order may be granted
by the Courts allowing treatment.
In this scenario, the child lacks capacity. In England a doctor may act to provide
treatment in the best interests of a child, even without parental consent. In this
case parental assent/consent was available. All clinical information should be
nevertheless clearly documented, alongside the reasons for the treatment plan, and
a consent Form 4 could also be used for procedures, e.g. the CT/lumbar puncture.
Holding and restraint
In general, the principle is to use restraint only as a technique of last resort. Minimal force
required for safety (of staff and patient) should be employed, by appropriate numbers of
experienced and trained staff. The plan should be discussed with the parent beforehand,
and opportunity for a discussion with parent and child should exist afterwards.
Answering notes
In this instance, oral medication is impractical (in option D), and as outlined above
the legal case to intervene is clear, ruling out the attractive option of C. This leaves the use of intramuscular, intravenous or inhalational methods alongside minimal
restraint. Most emergency departments would lack the facility of an anaesthetic
machine, thus the degree and duration of restraint needed to transfer this girl to
theatre and perform an inhalational induction makes option E impractical and
dangerous. Holding to achieve intravenous access may be reasonable, but the
choice of agents is not, as the CT scan and bloods should be relatively painless
therefore the fentanyl in option A may not be required, as such the increased
number of agents only serves to increase risks. In addition, a single dose of
midazolam is unlikely to be successful for the duration of the investigations required.
Thus, the option which minimises holding, involves only one agent, and provides an
appropriate duration would be intramuscular ketamine. Thought does have to be
given to inserting intravenous access and establishing safe monitoring for transfer,
which is probably best achieved in a resuscitation area
- A 34-year-old man sustained a traumatic brain injury 3days ago and is currently
intubated and ventilated on the intensive care unit. The nurse informs you during
your daily review that the plasma sodium concentration is 121mmol/L.
What other piece information would be most useful in establishing the cause?
A Urine output volume measurement
B Central venous pressure measurement
C Degree of peripheral oedema
D Urinary osmolarity measurement
E Plasma osmolarity measurement
A Urine output volume measurement
This question is testing your knowledge and reasoning in an attempt to differentiate
between two common causes of hyponatraemia in a patient with a head injury. The
differential diagnosis is between syndrome of inappropriate anti-diuretic hormone
(SIADH) and cerebral salt wasting (CSW).
Hyponatraemia is serious: in-hospital mortality is increased by 2–4 times and a
difference in survival outcome is still present at 1-year follow-up. Correcting the serum
sodium concentration is also hazardous and if done too rapidly may precipitate severe
neurologic complications, such as central pontine myelinosis, which can produce
spastic quadriparesis, swallowing dysfunction and pseudobulbar palsy.
The classic way to differentiate between causes of hyponatraemia is to assess fluid
balance (see Table 5.4).
CSW is a condition that is poorly understood. Proposed mechanisms include
increased sympathetic activity causing a higher glomerular filtration rate and excess
atrial natriuretic peptide (ANP) and brain natriuretic peptide (BNP) release resulting
in reduced renal water re-absorption.
It occurs most commonly in traumatic brain injury and presents in the first week
after injury and is normally self-limiting. The key clinical feature is hypovolaemia
with a high urine output production. The serum osmolarity may be normal or high
and urinary sodium is usually raised. The management involves replacing sodium
and water with 0.9% sodium chloride and if symptoms develop (anorexia, confusion,
unconsciousness and seizures) hypertonic saline may be indicated.
SIADH occurs as a result of traumatic brain injury, sub-arachnoid haemorrhage, brain
tumors and meningitis. Excess ADH results in increased water absorption from the
collecting duct of the nephron. The key clinical feature is hypervolaemia and low
urinary volume. The plasma has a low serum osmolarity due to the dilutional effect
of excess water and the urine osmolarity is usually high. The management involves
restricting water intake.In the intensive care unit great care is paid to getting the ‘numbers’ right. The fluid
balance is often adjusted according to a planned daily target. Central venous
pressure is of dubious benefit and a discrete value as is offered here is unhelpful.
Peripheral oedema may be multi-factorial and may be apparent even in the presence
of intravascular volume depletion. Osmolarity measurements are important in
making the diagnosis but in both differential diagnoses it may be normal and a
urinary sodium concentration is the more discerning test.
Considering the available options in the question above, urine output is the most
important piece of information: a high urine volume being produced in CSW and a
low urine volume being produced in SIADH.
- A 13-year-old boy presented to the emergency department with acute severe asthma
1 hour ago. His usual peak expiratory flow (PEF) is 68%, and takes long acting E2
agonist and high dose corticosteroid inhalers with montelukast tablets. You arecalled for advice as despite 4 x 2.5mg nebulised salbutamol, 500µg nebulised
ipratropium and 40mg of soluble prednisolone the patient’s PEF remains 35%
predicted, respiratory rate 32 per minute, speaking words, Spo2 93% on 10L/min of
warm humidified supplemental oxygen and transcutaneous carbon dioxide level of
5.1kPa.
Which of the following should be the next intervention?
A Rapid sequence induction using thiopentone and suxamethonium following
by positive pressure ventilation on an anaesthetic machine using isoflurane to
maintain anaesthesia and ease bronchoconstriction
B Commence an intravenous salbutamol infusion at 10µg/minute
C Give 20mmol of intravenous magnesium sulphate over 10–20 minutes
D Give a further 5mg nebulised salbutamol
E Give a loading dose of 5mg/kg aminophylline followed by an infusion at
500µg/kg/hour
- C Give 20mmol of intravenous magnesium sulphate over
10–20 minutes
This child has acute severe asthma and has failed to respond adequately despite
optimal first line therapy. Though at risk of further deterioration, the severity of his
current condition does not warrant intubation and positive pressure ventilation
– both of which may be hazardous. There is no evidence to support an additional
dose of nebulised salbutamol, or the use of intravenous bronchodilators. The next intervention likely to reverse his current pathophysiology is intravenous
(as opposed to nebulised) magnesium sulphate although the optimal regime
remains controversial.
- During the high dependency unit ward round you are called to the bedside of a 64-year-old gentleman with a background of hypertension who is awaiting primary angioplasty planned for the following day after being admitted with a non-ST
segment elevation myocardial infarction. He is feeling anxious and has central chest pain. The heart rate has recently increased to 150 beats per minute and the blood pressure is 90/60mmHg. The ECG shows atrial fibrillation and widespread ST segment depression.
What is your immediate course of action?
A Ring the anaesthetist on call and arrange for direct current (DC) cardioversion in theatre
B Ring the anaesthetist on call and arrange for direct current (DC) cardioversion on the HDU
C Administer amiodarone 300mg intravenously over 30 minutes
D Administer 2 g intravenous magnesium and optimise the serum potassium concentration
E Ring the cardiologist on call and organise an urgent angiography
- D Administer 2 g intravenous magnesium and optimise
the serum potassium concentration
○ Atrial fibrillation (AF) is a common problem in the critical care environment with up to 15% of medical critical care patients developing AF at some point during their stay.
The risk factors for developing AF are:
Patient factors:
t
• Age >65 years old
• Disease severity
• Hypertension
• Previous AF
• Congestive heart failure
• Chronic obstructive pulmonary disease
• Previous use of calcium-channel blockers, beta-blocker or angiotensin-converting enzyme-inhibitor and withdrawal of catecholamine infusions
Acute illness:
• Hypoxia
• Cardiac ischaemia
• Sepsis or systemic inflammatory response syndrome
• Fluid shifts (hypervolaemia and hypovolaemia)
• Low serum magnesium and potassium Iatrogenic
• Intra-cardiac catheter: central line or pulmonary artery catheter
○ AF probably occurs as a result of a final atrial insult (the last straw) on the
background of chronic disease most commonly hypertensive or ischaemic
myopathy. A sudden change in atrial dimensions as a result of filling pressures (either too high with fluid or too low with dehydration and sepsis), a change in electrochemical gradients across the myocyte (potassium and magnesium flux) or an ischaemic event are the common precipitating factors.
○ In health the atria contribute around 10% of cardiac output, increasing to 30% during exercise. This is well tolerated in patients with normal left ventricular function but in patients who depend on the higher filling pressures, loss of the ‘atrial kick’ results in low cardiac output. In addition the tachycardia results in poorer coronary blood flow and increased myocardial oxygen demand, which can result in even poorer ventricular performance. Patients in AF stay longer in ICUs and have an increased mortality in a general population but a causative relationship is hard to prove in medical or cardiac ICUs.
Management of acute compromised AF (as in this scenario) is not that easy from an exam point of view: most intensivists practice on their experience and there are no randomised controlled trials to base your decisions on. Advanced Life Support guidelines suggest direct current (DC) cardioversion in the peri-arrest scenario and all critical care recommendations are based on a mixed group of studies, which compare effective treatments. So what do you do?
In summary, the available evidence suggests:
• Magnesium is more effective than amiodarone in restoring sinus rhythm, equally effective as amiodarone at achieving rate control and is safe
• Amiodarone infusion converts AF into sinus rhythm in 70% of cases in the first 12 hours in medical critical care patients and 75% within 48 hours in general ICU population
• In a mixed population with left ventricular impairment amiodarone did not cause significant haemodynamic compromise but transient hypotension may occur in systemic illness
• The success rate of DC cardioversion in post-surgical and medical critical care patients is low and the recurrence rate is high
• Digoxin is not effective in this population
○ Given the information above, and that the single best answer questions test judgment and reasoning (not just recall of life-support algorithms) the question can be re-visited. DC cardioversion requires sedation, which takes time to organise no matter where you do it. It also has a low chance of success in this patient group and a high chance of recurrence as the presumed ischaemic focus has not been dealt with. Expediting the angiography may be prudent but you must stabilise the patient first. The choice between amiodarone and magnesium is less obvious, but given that
magnesium causes less hypotension and is at least as effective as amiodarone at rate and rhythm control, this is the most appropriate first step.
- A 72-year-old man on the intensive care unit has an APACHE II score of 48.
Which of the following variables is the most heavily weighted in intensive care
severity of illness scoring systems?
A Age
B Glasgow coma scale
C Systolic blood pressure / dose of vasopressor
D Pao2:Fio2 (PF ratio)
E Arterial lactate concentration
- B Glasgow coma scale
Most scoring systems use the Glasgow coma scale (GCS) or include data from the
GCS to assess the degree of neurological system failure. Furthermore, the GCS
frequently makes up a large component of the acute physiology score or equivalent.
For example, GCS constitutes 25% of the physiological score in Acute Physiology
and Chronic Health Evaluation (APACHE) II, 20% in APACHE III and 22% in Simplified Acute Physiology Score (SAPS) II. The explanation for this is that in multivariant
analysis of admission physiological variables, GCS is often the most highly predictive
of hospital mortality
- A 6-week-old boy presents with a 3-day history of progressive non-bilious vomiting and poor feeding. An ultrasound scan confirms the diagnosis of pyloric stenosis.
The capillary blood gas is shown in Table 5.1.The paediatric surgical team wants to perform an urgent pyloromyotomy. The infant last fed 12 hours previously.
The immediate anaesthetic management of this infant should be:
A Perform a rapid sequence induction because of delayed gastric emptying
B Insert a nasogastric tube to aspirate any residual gastric content before
induction of anaesthesia
C Postpone anaesthesia and surgery until the infant is adequately fluid
resuscitated and the acid-base balance corrected
D Perform a caudal block after induction of anaesthesia to minimise analgesic
opioid requirement
E Arrange for postoperative intensive care monitoring because of increased risk
of apnoea
- C Postpone anaesthesia and surgery until the infant is
adequately fluid resuscitated and the acid-base balance
corrected Pyloric stenosis is not a surgical emergency, but is a medical emergency. Gastric outlet obstruction and vomiting of gastric acid cause dehydration, hypovolaemia and a hypokalaemic, hyponatraemic, hypochloraemic metabolic alkalosis. Pre-operative rehydration and correction of acid-base and electrolyte abnormalities should be the immediate treatment goal.
There is little or no gastric emptying with pyloric stenosis. Aspirating the gastric content with a nasogastric tube and performing a rapid sequence induction are sensible precautions, but are not be the immediate anaesthetic management.
There is increased risk of postoperative apnoea with pyloric stenosis. Using local or regional anaesthesia to minimise postoperative analgesic opioid requirement and arranging close post operative monitoring are sensible, but are not the immediate anaesthetic management.
- A 6-year-old boy is admitted with fulminant hepatic failure, bleeding oesophageal varices, ascites and marked splenomegaly.
His liver function tests show an elevated bilirubin, alanine transaminases and aspartate transaminases. He has low albumin, prolonged prothrombin time and examination of his cornea on slit lamp examination demonstrate a brown, dark ring encircling his iris.
Which of the following is the most likely diagnosis for this clinical picture?
A Alpha-1 antitrypsin deficiency
B Wilson’s disease
C Primary biliary cirrhosis
D Haemochromatosis
E Sclerosing cholangitis
- B Wilson’s disease
○ Kayser-Fleischer rings (brown or dark rings encircling the iris) are pathognomonic of Wilson’s disease which is an autosomal recessive inherited disorder characterised by toxic accumulation of copper in the liver and brain. The ATP7B enzyme prevents excessive accumulation of copper by either combining it with caeruloplasmin and releasing it into the bloodstream, or secreting it in the bile. The functions of this enzyme are affected in Wilson’s disease, causing the toxic accumulation of copper in the blood.
Children usually present with hepatic complications such as hepatitis, cirrhosis or fulminant hepatic failure. Adults tend to present with neurophsychiatric signs including dysarthria, tremors, seizures, migraine, ataxia, cognitive decline and behavioral disturbances.
Kayser-Fleischer rings are caused by deposition of copper in the Descemet’s
(basement) membrane and can be visualised by slit lamp examination. Treatment for Wilson’s disease consists of administering chelating agents like penicillamine or in extreme cases hepatic transplantation.
○ Alpha-1 antitrypsin is a protease inhibitor and its deficiency leads to cholestasis and pulmonary symptoms including emphysema.
○ Primary biliary cirrhosis is caused by damage of interlobular bile ducts, leading to cholestasis coupled with portal hypertension and cirrhosis.
○ Haemochromatosis is caused by increased iron absorption and deposition in the liver, heart or pancreas.
○ Primary sclerosing cholangitis is inflammation of intra- and extra-hepatic ducts, which leads to liver failure and death.
