Answer: E. Adenosine

Paroxysmal supraventricular tachycardia often terminates spontaneously or with reflex vagal stimulation such as a Valsalva manoeuvre, immersing the face in ice-cold water or carotid sinus massage.

If the effects of reflex vagal stimulation are transient or ineffective, or if the arrhythmia is causing severe symptoms, the treatment of choice is intravenous adenosine. The patient’s ECG should be continuously monitored throughout.

The doses in adults are as follows:
• Initial dose of adenosine is 6 mg by rapid IV bolus
• If unsuccessful, give another dose of adenosine 12 mg by rapid IV bolus
• If unsuccessful, give a further dose of adenosine 12 mg by rapid IV bolus.

If adenosine is ineffective or contra-indicated, intravenous verapamil can be used as an alternative, but it should be avoided in patients recently treated with beta-blockers.

If the patient is haemodynamically unstable, or if the use of drug treatment has failed to restore sinus rhythm, electrical cardioversion will be necessary.

Recurrent episodes of paroxysmal supraventricular tachycardia can be treated by catheter ablation, or prevented with drugs such as flecainide, sotalol, diltiazem or verapamil.

RCEM syllabus reference:
CP3. Palpitations
CC3. Arrhythmias

Answer: A. Proximal humerus

Intraosseous access is indicated in a trauma, burns or resuscitation setting and:
• Other attempts at venous access fail or;
• They will take longer than one minute to carry out

It is the recommended technique for circulatory access in paediatric cardiac arrest (APLS 6th edition). It can also be used in any situation where blood sampling or intravenous access is urgently needed, and cannulation is difficult and time-consuming. It is a temporary measure to allow stabilisation and facilitation of definitive, long-term intravenous access.

The potential complications of intraosseous access include:
• Compartment syndrome
• Infection
• Fracture

The contraindications to intraosseous access include:
• Use on the side of definitely fractured bones (due to risk of compartment syndrome)
• Use on limbs with possible proximal fractures
• Use at sites of previous attempts
• Osteogenesis imperfecta
• Osteopetrosis

There are numerous potential sites of insertion, including:
• Proximal humerus – 1 cm above the surgical neck
• Proximal tibia – anterior surface, 2-3 cm below the tibial tuberosity
• Distal tibia – 3 cm proximal to the most prominent aspect of the medial malleolus
• Femoral – Anterolateral surface, 3 cm above the lateral condyle
• Iliac crest
• Sternum

RCEM syllabus reference:
RP4. Major trauma
RP7. Shock

Answer: E. High-flow oxygen via a non-rebreathe mask

This patient displays signs of decompression sickness (DCS), otherwise known as ‘The Bends’. DCS occurs when gas bubbles form in tissues and/or the blood during or after a decrease in environmental pressure. In the UK, this is most commonly seen in divers. 90% of cases of DCS appear within 30 minutes – 6 hours and will occur during or after ascent. 50% of these cases will present within the first hour. Rarely, there may be a longer latent period from 24 to 36 hours.

DCS can present with a myriad of clinical presentations as bubbles can form in most body parts, including:
• Limb or joint pain – deep ache type pain, worse in arms and on movement or palpating
• Girdle pain – pain coming from the back and spreading to the abdomen
• Neurological symptoms such as tingling, weakness, poor coordination, memory loss, unconsciousness
• Chest pain and breathless
• Rash – often mottled called cutis marmorata
• Constitutional symptoms such as malaise, lethargy and headache

Currently, there are no specific diagnostic tests, investigations or imaging techniques which would confirm or exclude a diagnosis of DCS.

Management in the Emergency Department is oxygen. All patients should be started on high flow at 15 L/min via a non-rebreathe mask regardless of oxygen saturation. It is also recommended to call the national diving accident helpline for expert advice, where a decision regarding decompression therapy can be discussed. A chest X-ray to look for a pneumothorax or pulmonary oedema and oral or IV fluids also often form part of the initial management.

Decompression therapy is the definitive treatment for DCS. The patient is re-pressurised in a chamber, breathing 100% oxygen at a high partial pressure.

Do not give Entonox (50% nitrous oxide/50% oxygen) under any circumstance, as the nitrous oxide is highly soluble and will increase the inert gas load, making symptoms of DCS worse. Similarly, avoid painkillers, as this can also worsen symptoms.

Although a CT may be indicated for some neurological presentations, in the context of a recent dive and other manifestations of DCS, this would not be considered necessary in the immediate management.

Acetazolamide has no role to play in the treatment of DCS. It can be used prophylactically and as a treatment for high-altitude illness.

RCEM syllabus reference:
EnvC4. Decompression sickness

Answer: A. Age under 12 years

Codeine phosphate is a weak opiate that can be used to relieve mild to moderate pain where other painkillers such as paracetamol or ibuprofen have proved ineffective. It can also be used in the treatment of acute diarrhoea and dry or painful coughs.

The following are contra-indications to the use of all opioids:
• Acute respiratory depression
• Comatose patients
• Head injury (opioid analgesics interfere with pupillary responses vital for neurological assessment
• Raised intracranial pressure (opioid analgesics interfere with pupillary responses vital for neurological assessment)
• Risk of paralytic ileus

The following are specific contra-indications to the use of codeine phosphate:
• In children under 12 years due to the significant risk of respiratory side effects
• In patients of any age who are known to be ultra-rapid metabolisers of codeine (CYP2D6 ultra-rapid metabolisers)
• In breastfeeding mothers because it can pass to the baby through breast milk, and mothers vary considerably in their capacity to metabolise codeine. There is, therefore, a significant risk of opioid toxicity in the infant.

Codeine should only be used to relieve acute moderate pain in children older than 12 if it cannot be relieved by other painkillers such as paracetamol or ibuprofen alone. A significant risk of serious and life-threatening adverse reactions has been identified in children with obstructive sleep apnoea who received codeine after tonsillectomy or adenoidectomy.

RCEM syllabus reference:
PC1. Analgesics

Answer: A. Proximal radioulnar joint

Infants and young children are particularly prone to subluxation of the head of the radius at the proximal radioulnar joint. This is often referred to as a ‘pulled elbow’ as it typically occurs following a quick pull on the child’s arm.

The sudden pulling of the arm tears the attachment of the annular ligament, where it is loosely attached to the neck of the radius. The radial head then moves distally, partially out of the torn annular ligament. The proximal part of the ligament may become trapped between the head of the radius and the capitellum of the humerus.

The arm is typically held motionless at the child’s side, with them refusing to move it. The arm is often held in slight flexion with pronation and adduction, and there is often tenderness over the radial head on palpation.

Reduction of a subluxated radial head is easily performed in the Emergency Department, and complications are rare. There are two typical manoeuvres, supination and pronation. Using the supination technique, the forearm is twisted or rotated outwards; this can also be followed by flexion of the elbow. Using the pronation technique, the forearm is twisted or rotated inwards. Both methods are generally safe and effective, although bruising can occur, and they can be painful.

RCEM syllabus reference:
TP7. Limb and joint injury
TC2. Limb and joint injury including bony and musculo-tendinous injuries and complications