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Drug overdose and abuse
• Activated charcoal is ineffective in the case of iron,
lithium, alcohol and cyanide poisoning or overdose.
• Whole bowel irrigation is not routinely recommended
but can be considered in iron overdose or in the case of
enteric-coated drugs.
Removal of the drug from the gastrointestinal tract is
controversial. The potential benefits of reducing drug absorption may be outweighed by the hazards of the methods used (e.g. aspiration of stomach contents) or may
cause a paradoxical increase in drug absorption. It should
be considered only for people who present early, are fully
conscious with a protected airway and are at risk of significant harm because of the poisoning. Induced emesis is not
recommended. Gastric lavage should be undertaken only
within 1 hour of ingestion.
Increase elimination of drug
Elimination of drugs can be increased by urinary alkalinization or through extracorporeal circuits, including haemodialysis, or haemoperfusion. Urinary alkalinization increases
renal excretion of mildly acidic drugs. It is used in severe
salicylate, phenobarbital and amphetamine overdose. A
high urinary output is required, and fluid balance, electrolyte levels and acid–base status should be monitored very
carefully.
Extracorporeal circuits are used when the clinical condition fails to respond to maximum supportive care, or when
the serum level of the drug is known to result in significant
risk of organ failure and the rate of extracorporeal clearance exceeds that of endogenous hepatic or renal clearance.
Haemodialysis is especially useful for overdose of salicylate,
lithium, alcohol and polyethylene glycol. With haemoperfusion, blood passes through a cartridge containing a sorbent,
and can enable the removal of protein-bound drugs (e.g.
phenytoin and tricyclic antidepressants).
PARACETAMOL OVERDOSE
Paracetamol overdose is the most common agent of intentional self-harm, and the most common cause of acute
liver failure. Overdose, even in small amounts, can cause
fatal liver damage. To prevent this, paracetamol should be
suspected as a component of all overdoses. Plasma concentrations should be measured and compared against a nomogram (paracetamol treatment graph); see Fig.38.1. Patients
with plasma concentrations above the treatment line are at
risk of liver damage and require antidote treatment with
N-acetylcysteine. It is important to know the time the
paracetamol was consumed, whether the intake of the drug
was staggered and whether it was a mixed overdose. Certain
individuals are at higher risk of paracetamol-induced liver
disease, including patients who are malnourished, have
preexisting liver disease, chronic alcoholism or HIV, or are
taking liver enzyme inducing drugs (e.g. phenytoin, carbamazepine). Treatment includes giving activated charcoal if
the individual presents within 1 hour. Paracetamol levels are
measured 4 hours after ingestion; if serum levels are above
the treatment line, infusion of N-acetylcysteine is commenced. This infusion lasts around 24 hours. In the context
of paracetamol overdose with a delayed presentation (>8
hours), N-acetylcysteine infusion should be started immediately until a drug level is available. Following the overdose
the patient should be closely monitored, with careful attention to liver function test levels, glucose level and international normalized ratio (INR). A rising INR >2 at 24 hours
should prompt discussion with a specialist liver centre. In
the context of a staggered overdose, patients presenting
with evidence of severe toxicity or fulminant hepatic failure,
N-acetylcysteine infusion should be started immediately.
Specific antidotes
Advice for the management of overdose of any drug or ingestion of any poison can be obtained 24 hours a day from
several poisons information centres run by the National
Poisons Information Service. Each emergency department
and hospital switchboard will have a list of national numbers, as well as access to the National Poisons Information
Service online database and TOXBASE, which provides a
vast amount of detailed information.
Table38.1 summarizes the features and management of
overdose of some of the more common drugs.
Psychiatric and social assessment
Once the acute event and medical management is completed, the patient's psychiatric state, ongoing risk of
suicide and social circumstances should be assessed, however trivial the overdose may have appeared. Where appropriate, psychiatrists and social care workers should be
involved.
388
ILLEGAL DRUGS
Because of their nature, there is often less information
available on the treatment of adverse effects associated with
illicit drugs. In addition, new drugs emerge and quickly become widely used. TOXBASE is very useful in this regard.
Table38.2 details some of the features seen with com-
monly used illegal drugs.
ALCOHOL MISUSE AND WITHDRAWAL
Alcohol is widely used throughout the world. The lifetime
incidence of alcohol dependence in the United Kingdom
is 4%, and more than 24% of the English population consumes alcohol in a way that is potentially, or actually, harmful to their well-being. Alcohol misuse is a huge problem
Alcohol misuse and withdrawal
120
0.8
Time (hours)
Plasma-paracetamol concentration (mmol/litre)
Plasma-paracetamol concentration (mg/litre)
3838
110
100
90
80
70
60
50
40
30
20
10
Fig.38.1 Paracetamol nomogram. (Reprinted with permission from the Royal College of Emergency Guidance. https://
www.rcem.ac.uk/docs/Paracetamol%20Overdose/Annex%201_The%20treatment%20nomogram%20and%20
Annex%202_Technical_info.pdf.)
in terms of morbidity, mortality and healthcare costs. The
CAGE questionnaire is commonly used as a screening tool
for alcohol problems.
Treatment line
0
0246810
0.7
0.6
0.5
0.4
0.3
0.2
0.1
0
12 14 16 18 20 22 24
• Systemic complications; for example:
• Gastrointestinal: gastritis, oesophagitis, varices,
alcoholic liver disease (see Chapter 29).
• Cardiovascular: arrhythmia, cardiomyopathy,
COMMUNICATION
The CAGE questionnaire:
• Have you ever felt you needed to cut down on
your drinking?
• Has anyone ever annoyed you by criticizing your
drinking?
• Have you ever felt guilty about your drinking?
• Have you ever needed a drink in the morning –
an ‘eye-opener’ – to make yourself feel better?
A positive answer to any of these questions is
indicative of possible alcohol dependence.
hypertension.
• Respiratory: increased incidence of pneumonia and TB
due to reduced clearance of pathogens.
• Neurological: cortical atrophy, cerebellar degeneration,
peripheral neuropathy, Wernicke encephalopathy/
Korsakoff syndrome.
• Endocrine: gynaecomastia, testicular atrophy,
osteoporosis.
• Increased risk of cancer, particularly oesophageal and
head and neck cancers.
Alcohol withdrawal
Patients experiencing alcohol withdrawal are difficult to
treat and, despite initial willingness, often self-discharge.
The standard treatment is a course of benzodiazepines, usu-
Alcohol misuse can result in acute intoxication, problems
associated with alcohol withdrawal and systemic complications of alcohol use:
• Acute intoxication: alcohol causes euphoria and
reduced inhibition. In greater quantities it may cause
reduced conscious level, respiratory depression, atrial
fibrillation, hypoglycaemia and hypotension.
• Alcohol withdrawal: tremor, sweating, tachycardia,
irritability, agitation, hallucinations, delusions, seizures.
Symptoms usually start within 24 hours of the last
alcohol intake.
ally chlordiazepoxide, which is slowly reduced over several
days; most hospitals have a dosing protocol. The Clinical
Institute Withdrawal Assessment for Alcohol (CWIA) scale
is used to quantify the severity of the alcohol withdrawal
syndrome and to guide the patient’s chlordiazepoxide requirement. Delirium tremens, or delirium- associated alcohol withdrawal, is a severe form of withdrawal which
occurs in approximately 5% of patients who undergo ethanol withdrawal. Delirium tremens is associated with a
high risk of morbidity and death. The onset is usually between 2 and 5days following cessation of alcohol intake.
389
Drug overdose and abuse
Features include severe tremor, clouding of consciousness,
delusions, tachycardia, agitation, fever and severe hallucinations (mainly visual but can be tactile or auditory and
often cause extreme fear). Delirium tremens is treated by
calming and reorientation of the patient, and use of oral
benzodiazepines, lorazepam being first line. If seizures occur, these should be treated with intravenous benzodiazepines. Occasionally antipsychotics such as haloperidol are
required for severe withdrawal psychosis.
RED FLAG
If seizures occur in a patient withdrawing from
alcohol, consider if there is another intracranial
disorder. These patients are at higher risk of
subdural haemorrhages.
Wernicke encephalopathy/ Korsakoff psychosis
Wernicke encephalopathy is an acute life-threatening neurological syndrome consisting of confusion, ophthalmoplegia and ataxia. The most common cause is thiamine
deficiency associated with alcoholism. If not treated, it can
lead to irreversible amnesia: Wernicke–Korsakoff psychosis. This is a late neuropsychiatric syndrome characterized
by memory loss and confabulation.
Heavy alcohol consumption can affect absorption of thiamine (vitamin B1), and people with alcoholism can be at
risk of this condition despite having a normal balanced diet.
To avoid this thiamine in the form of Pabrinex (IV vitamin
B with ascorbic acid) should be administered intravenously
for a minimum of 48 hours, and for 1week in the case of
Wernicke encephalopathy, followed by oral administration
of thiamine and vitamin B replacement.
RED FLAG
If thiamine deficiency is suspected, thiamine
should be replaced before glucose is replaced.
Prolonged carbohydrate administration without
thiamine supplementation has been reported to
precipitate Wernicke encephalopathy.
Long-term treatment
Regular psychosocial input is essential. This may include
counselling, cognitive behavioural therapy and self-help
groups (e.g. Alcoholics Anonymous). Once withdrawal has
been completed, there are three currently recommended
pharmacological aids which can be considered along with
individual psychological intervention:
• Naltrexone: a partial agonist at opioid receptors. It
reduces the pleasurable effects from alcohol; it reduces
cravings, and is associated with a lower relapse rate. It
is useful in patients who are binge drinkers.
• Acamprosate (calcium acetyl homotaurinate): This
blocks γ-aminobutyric acid receptors and reduces
N-methyl-d-aspartate excitation. It reduces cravings
and does not interact with alcohol. It can be given after
detoxification to maintain stabilization.
• Nalmefene: This is used in individuals with
alcohol dependence without physical withdrawal
symptoms and who do not require immediate
detoxification.
Chapter Summary
• In a patient with an overdose it is important to establish the risk of the overdose. What
drugs were taken? Was it a mixed overdose? How many tablets were taken and at what
time? Was it staggered?
• Establish whether the intent was suicide or a call for help. Planned suicide attempts with
no intention to be found represent the highest risk. All patients should be seen by a
psychiatrist following an overdose.
• Always consider whether an overdose has been taken in an unconscious patient. Assess
the patient with a systematic ABC approach. Assess the conscious level and consider if
the patient can protect their own airway.
• Paracetamol and salicylate levels should be measured in all patients suspected of taking
a drug overdose.
• Specific drug overdoses have specific treatments. TOXBASE is a very useful guide.
• Alcohol misuse is common. Screen all patients for alcohol dependence and consider the
need for oral benzodiazepines to prevent alcohol withdrawal in hospitalized patients.
Have a low threshold to give thiamine replacement to reduce the risk of the patient
developing a Wernicke–Korsakoff syndrome.
390
Further reading
3838
FURTHER READING
Battista, E., 2012. Crash Course: Pharmacology, fourth ed. Mosby,
Edinburgh.
National Institute for Health and Clinical Excellence, 2004. Self-
harm. Clinical guideline CG16. Available online at: http://www.
nice.org.uk/CG16.
National Institute for Health and Clinical Excellence, 2011. Alcohol
dependence and harmful alcohol use. Clinical guideline CG115.
Available online at: http://www.nice.org.uk/CG115.
Vale, J.A., Bradberry, S.M., Bateman, D.N., 2010. Poisoning by
drugs and chemicals. In: Warrell, D.A., Cox, T.M., Firth, J.D.
(Eds.), Oxford Textbook of Medicine. fifth ed. Oxford University
Press, Oxford, pp. 873–922.
391
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SELF-ASSESSMENT
Single best answer (SBA) questions � � � � � � � � � � � � � � � � 395
Extended-matching questions (EMQs) � � � � � � � � � � � � � � 409
SBA answers � � � � � � � � � � � � � � � � � � � � � � � � � � � � 421
EMQ answers � � � � � � � � � � � � � � � � � � � � � � � � � � � � 431
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Single best answer (SBA)
questions
Chapter28 Respiratory system
1. A 51-year-old builder was involved in a high-speed
road traffic incident. Basic first aid was provided
at the scene according to advanced trauma life
support principles and he was subsequently
transferred to hospital. Whilst the builder was being
formally assessed, one of the FY2 doctors in the
emergency department noticed the patient's oxygen
saturations had dropped to 85%. He is concerned
the patient may have a tension pneumothorax.
Which one of the following is not a feature of a
tension pneumothorax?
A. The trachea is deviated towards the affected
side.
B. Increased percussion note over the
pneumothorax.
C. Asymmetrical expansion of the chest.
D. Absent/diminished breath sounds over the
pneumothorax.
E. A raised jugular venous pressure.
2. A 51-year-old Pilates instructor experienced a
bimalleolar fracture of her ankle which required open
reduction and internal fixation. The operation was
a success, and she was discharged with a 3-week
course of low-molecular-weight heparin (LMWH).
Four weeks after the operation she developed
progressive shortness of breath and a dry cough.
She attended the emergency department, where
a CT pulmonary angiogram revealed large bilateral
pulmonary embolisms (PEs). Which one of the
following statements would be correct regarding
pulmonary embolus?
A. The S1Q3T3 pattern is the most common EKG
abnormality.
B. This case is unusual since haemoptysis is the
most common symptom.
C. It is rarely associated with undiagnosed
malignancy.
D. One of the earliest signs is a resting tachycardia.
E. It requires 1year of warfarin therapy.
3. A 17-year-old girl is admitted to hospital with a
wheeze and severe dyspnoea. Which one of the
following statements is true with regard to the
assessment and management of an acute asthma
attack?
A. The peak flow measure is unhelpful.
B. A normal Paco2 level is reassuring.
C. Intravenously administered magnesium may be
indicated.
D. Death is extremely rare.
E. Intravenous bronchodilator therapy is much
better than nebulized therapy.
4. A 67-year-old gardener presents to his general
practitioner with a 3-day history of productive cough,
fevers and anorexia. On examination the patient
has coarse crackles at the right base with bronchial
breathing. The GP suspects this is pneumonia and
refers the patient to be seen in hospital for a CXR
and blood cultures. Which one of the following does
not score a point in the severity assessment for
community-acquired pneumonia?
A. Blood urea level greater than 7 mmol/L.
B. Systolic blood pressure greater than 90 mmHg.
C. Respiratory rate greater than 30 per minute.
D. Confusion.
E. Age more than 65years.
5. A 72-year-old retired car mechanic presents
with a 6-month history of weight loss, cough
and occasional haemoptysis. A CXR reveals a
mass in the right hemithorax with associated
hilar shadowing. A CT scan is performed, and
subsequent bronchoscopy and biopsy makes the
diagnosis of squamous cell carcinoma of
the lung. Which one of the following statements
is true regarding squamous cell carcinoma of
the lung?
A. It is associated with the syndrome of
inappropriate antidiuretic hormone secretion.
B. It is associated with hypercalcaemia.
C. It is the most common cause of Eaton–Lambert
myasthenic syndrome.
D. Chemotherapy is the mainstay of treatment.
E. It rarely metastasizes to bone.
6. A 60-year-old man presents with a 3-month history
of worsening shortness of breath and a dry cough.
He has never smoked. A CXR is ordered and shows
diffuse peripheral infiltrate opacifications. Which
of these drugs is most likely to be associated with
interstitial lung disease?
A. Amiodarone.
B. Amoxicillin.
C. Doxycycline.
D. Enalapril.
E. Sotalol.
395
Single best answer (SBA) questions
7. A 46-year-old woman with a known diagnosis of
sarcoidosis presents to the emergency department
with worsening dyspnoea. A chest X-ray (CXR) is
performed, and she is subsequently reported as
having stage 3 pulmonary sarcoidosis. Which one of
the following is the CXR most likely to show?
A. A pleural effusion.
B. Bilateral hilar lymphadenopathy.
C. Bilateral hilar lymphadenopathy with
reticulonodular shadowing.
D. Fibrocystic sarcoidosis typically with upward hilar
retraction, cystic and bullous change.
E. Bilateral pulmonary infiltrates.
8. A 19-year-old student is brought by ambulance to
the emergency department with severe dyspnoea.
His peak flow is 100 L/min (normally 650 L/min). His
respiratory rate is 40 per minute, and auscultation of
his chest reveals barely audible breath sounds. His
mother tells you that he had been hyperventilating
for approximately 30 minutes before admission.
What would you expect the arterial blood gas result
to be?
A. pH 7.29, Paco2 6.3 kPa, Pao2 9.2 kPa,
bicarbonate 45 mmol/L.
B. pH 7.51, Paco2 7.9 kPa, Pao2 9.6 kPa,
bicarbonate 37 mmol/L.
C. pH 7.39, Paco2 5.3 kPa, Pao2 7.1 kPa,
bicarbonate 30 mmol/L.
D. pH 7.51, Paco2 2.0 kPa, Pao2 9.6 kPa,
bicarbonate 14 mmol/L.
E. pH 7.57, Paco2 3.2 kPa, Pao2 10.2 kPa,
bicarbonate 27 mmol/L.
9. A 56-year-old publican is admitted to the emergency
department with dyspnoea. Whilst he is waiting to
be seen by the doctor, the nurse administers oxygen
through a nasal cannula at 2 L/min as his oxygen
saturations were 89%. Which one of the following
most accurately reflects the fraction of oxygen
inspired (Fio2)?
A. 98%.
B. 50%.
C. 35%.
D. 28%.
E. 24%.
10. A 65-year-old man presents with a 1-month history
of shortness of breath and pleuritic chest pain. He
also reported a 6 kg weight loss in the past few
months. He has a medical history of hypertension.
He used to be a textile factory worker. On the basis
of the history, which statement is true regarding the
most likely diagnosis?
A. The patient has a tumour of the lung
parenchyma.
B. The condition usually accompanies pulmonary
asbestosis.
C. Diagnosis is achieved by observing pleural
plaques on CXR or CT.
D. The condition has a good prognosis.
E. Diagnosis may result in compensation for the
patient and/or family.
11. A 45-year-old originally from sub-Saharan Africa
presents to the emergency department with a
history of progressively worsening shortness of
breath. On further questioning he admits to having
a cough productive of sputum with occasional
haemoptysis and night sweats. Amongst other
tests a sputum sample is sent for culture, including
AAFB. This comes back positive, and tuberculosis
(TB) is diagnosed. What is the appropriate drug
treatment?
A. Six months of combination therapy: rifampicin,
isoniazid, pyrazinamide and ethambutol
for 4months followed by isoniazid and
pyrazinamide alone for 2months.
B. Twelve months of combination therapy:
rifampicin, isoniazid, pyrazinamide and
ethambutol for 4months followed by rifampicin
and pyrazinamide alone for 2months.
C. Six months of combination therapy: rifampicin,
isoniazid, pyrazinamide and streptomycin
for 4months followed by rifampicin and
pyrazinamide alone for 2months.
D. Six months of combination therapy: rifampicin,
isoniazid, pyrazinamide and ethambutol
for 4months followed by rifampicin and
pyrazinamide alone for 2months.
E. Six months of combination therapy: Rifampicin,
isoniazid, pyrazinamide and ethambutol for
4months followed by rifampicin and isoniazid
alone for 2months.
12. An 86-year-old man with a history of chronic
obstructive pulmonary disease (COPD) is brought
in to the emergency department from a nursing
home with acute onset shortness of breath. On
examination he is alert and maintaining his own
airway, but he is visibly in respiratory distress,
gasping for air, and using accessory muscles of
respiration with a respiratory rate of 36 per minute.
His temperature is 38.5°C. His oxygen saturations
are 88% on 15 L of oxygen through a non-rebreather
mask. He is tachycardic with a pulse of 110. His
blood pressure is 120/80 mmHg. What is the initial
treatment?
A. Continue with oxygen alone. Perform further
investigations before commencing other
treatment as management will depend on the
underlying diagnosis.
396
Single best answer (SBA) questions
B. Get senior help. Raise the edge of the bed.
Change the oxygen delivery system to a venturi
mask. Commence back-to-back nebulized
bronchodilator therapy and intravenously
administer hydrocortisone.
C. Get senior help. Raise the edge of the
bed. Commence back-to-back nebulized
bronchodilator therapy, intravenous fluids and
empirical antibiotics.
D. Bleep the anaesthetist so the patient can be
intubated.
E. Try simple manoeuvres to improve the
patient’s oxygenation such as raise the edge of
the bed and suction of excessive secretions.
Continue with oxygen and give nebulized
salbutamol. If there is no improvement, consider
intravenously administered magnesium and
hydrocortisone. Reassess the patient after every
intervention.
13. For the case in the previous question, what is the
least useful initial test that you could request?
A. Arterial blood gas (ABG).
B. Chest X-ray (CXR).
C. Full blood count, urea and electrolytes,
C-reactive protein.
D. CT pulmonary angiogram.
E. Urine dip.
14. A 63-year-old comes to the emergency department
with pleuritic chest pain and shortness of breath.
He returned from a trip to visit his family in Australia
2days ago. It was a long-haul flight lasting over 15
hours. A pulmonary embolism (PE) is suspected,
and a CT pulmonary angiogram is ordered. What
investigation should be performed before the scan
can take place?
A. Kidney function tests.
B. Chest X-Ray (CXR).
C. D-dimer.
D. Liver function tests.
E. V./Q. scan.
15. A 25-year-old goes to see her GP with a dry cough
and some shortness of breath. She has a fever and
feels generally unwell with flulike symptoms. She
returned from a summer holiday in Spain 6days
ago. She has a diagnosis of type 1 diabetes mellitus,
for which she has an insulin pump. She is a smoker.
Considering the history, what pathogen causing
pneumonia should you be worried about?
A. Streptococcus pneumoniae
B. Mycoplasma tuberculosis
C. Influenza virus
D. Legionella pneumophila
E. Methicillin-resistant Staphylococcus aureus
Chapter29 Gastrointestinal and
hepatobiliary systems
1. A 67-year-old man underwent an
oesophagogastroduodenoscopy (OGD) for reflux
symptoms. Barrett oesophagus was diagnosed.
Which one of the following statements regarding this
condition is true?
A. Approximately 25% of cases will progress to
adenocarcinoma.
B. The condition predominantly affects the middle
third of the oesophagus.
C. The condition is asymptomatic in most cases.
D. The condition is treated surgically in the first
instance.
E. The condition is characterized by dysplasia
from squamous cell epithelium to columnar cell
epithelium.
2. A 43-year-old midwife presents with constant,
epigastric pain radiating to the back. She had been
suffering with intermittent episodes of right upper
quadrant (RUQ) pain for the previous 6months.
Serum amylase level is 1400 U/mL. A diagnosis of
suspected pancreatitis is made. Which one of the
following statements is true?
A. A serum amylase level of more than 2500 U/mL
indicates severe pancreatitis.
B. The most likely cause is gallstones.
C. The Rockall score is used to assess severity.
D. A recognized early complication of pancreatitis is
pseudocyst formation.
E. Pancreatitis is the only possible diagnosis.
3. A 58-year-old person with alcoholism with known
cirrhosis presents with copious haematemesis.
A variceal bleed is suspected. Which one of the
following statements is true for the management of a
large upper gastrointestinal (GI) tract haemorrhage?
A. A detailed history and examination is a priority.
B. A large bleed causes an immediate decrease in
haemoglobin concentration.
C. A large bleed causes a decrease in urea
concentration.
D. The investigation of choice is a CT scan.
E. Rebleeding carries higher mortality.
4. A 24-year-old primary school teacher presents with
abdominal pain and bloody diarrhoea. He has a
colonoscopy which shows features of ulcerative
colitis (UC). Which one of the following features is
associated with UC?
A. Transmural inflammation.
B. Pseudopolyps.
C. Perianal lesions.
D. Skip lesions.
E. More common in smokers.
397