A 23 year old male presents to the emergency department with sudden onset breathlessness and right sided chest pain that occurred while he was scuba diving. On general inspection, he is noted to 6'4" tall. His heart rate and blood pressure is normal, trachea is central, the right side of the chest is very resonant to percussion. There are reduced breath sounds on the right side of his chest on auscultation.

What is the most likely diagnosis?

Options:
explanation: Primary pneumothoracies are more common in tall, thin, young men and scuba diving is a significant risk factor due rapid expansion of the lungs when ascending from a dive. Examination findings are also much in keeping with a pneumothorax, with hyper-resonance and reduced breath sounds on the affected side. This represents air in the pleural space that is more resonant than the surrounding lung tissue and a reduction in functioning lung tissue, which that is being compressed by surrounding free air. This patient will likely be managed by needle aspiration, as they are symptomatic with breathlessness. They will also likely be advised to avoid scuba diving in future
name: Pneumothorax
label: a
answer: yes
explanation: Pulmonary embolism characteristically presents with sudden onset pleuritic chest pain. However, pneumothoracies can also present with sudden onset pleuritic pain. When considering the risk factors and examination findings in this case, pneumothorax is the most likely diagnosis as pulmonary embolism does not present with these examination findings
name: Pulmonary embolism
label: b
answer: no
explanation: Tension pneumothorax is a life-threatening condition that should always be considered in anyone with suspected pneumothorax. However in this case this patient has a normal heart rate and blood pressure and their trachea is central. In the presence of a well patient with normal observations and a central trachea, it is very unlikely to be a tension pneumothorax, therefore a pneumothorax is a more appropriate single best answer
name: Tension pneumothorax
label: c
answer: no
explanation: Pleural effusion is fluid in the pleural space, in contrast to pneumothorax which is air in the pleural space. Therefore examination findings are slightly different. They may also present with reduced breath sounds on the affected side, but on percussion they would present with a "stony" dullness, when compared to the other side. This is because the fluid in the pleural space is denser than the surrounding lung tissue. The examination findings are more in keeping with a pneumothorax in this case. In addition, this case does not suggest a clear causative factor for a pleural effusion e.g. pneumonia, heart failure, inflammatory disease, whereas there is a clear causative factor for a pneumothorax
name: Pleural effusion
label: d
answer: no
explanation: Bullous lung disease is a good differential for pneumothorax, especially in a patient with co-existing chronic obstructive pulmonary disease (the most common cause of bullous disease). However, in a 23 year old patient, it is a very unlikely that this patient will have COPD or any bullous disease. Therefore a primary pneumothorax in previous healthy lung tissue is the most likely diagnosis
name: Bullous lung disease
label: e
answer: no

Correct answer: a