Pick ‘n’ Mix Week 3 February 2023

Estimated Reading Time: 6 minutes

We are really grateful to Trudie Pestell for sharing this fabulous education initiative that she has been producing for University Hospital Southampton Emergency Department for a while.

Each week we will bring you some clinical pearls to add in to your knowledge and understanding with links to other resources as well as an OSCE of the week.


An acute impairment in gas exchange between the lungs and the blood causinghypoxia with or without hypercapnia. There are two types, and you may need an arterial blood gas (please use local anaesthetic) to tell the difference.

Type 1

Type 2


Hypoxaemia (PaO2< 8kPA or 60 mmHg)

Hypoxaemia (PaO2< 8kPA or 60 mmHg)

Carbon Dioxide

Normocapnia (PaCO2 <6.0kPA or 45mmHg)

Hypercapnia (PaCO2>6.0kPa or 45mmHg)


  • Ventilation-perfusion(V/Q) mismatch(most common)
  • Alveolar
  • Hypoventilation
  • Diffusion impairment
  • Shunt
  • Inability to sense increasing arterial CO2 levels
  • Increased CO2production
  • Increased dead space
  • Decreased tidal volume
  • Pump failure


  • Bronchoconstriction
  • Pulmonary oedema
  • Pulmonary embolism
  • ARDS
  • Pneumonia
  • Atelectasis
  • COPD
  • Neuromuscular disease
  • Head trauma
  • Sedation
  • Chest wall dysfunction
  • Upper airway obstruction


  1. ABC (obviously)
  2. Supplemental oxygen
  3. Treat underlying causes
  4. Consider non invasive ventilation
  • Usually occurs in the first 24 hours of treatment
  • A cytokine mediated systemic reaction in reponse to dead spirochetes
  • Self-limiting and usually resolves within 24–48 hours, but it is important to counsel patients on this side effect, as it may mean people discontinue treatment.

The case of the droopy face a sore ear

The beginning:

A 79 year old female is brought into ED by her son. He noticed that last night, her speech was ‘a little funny’. This morning, the left side of her face was droopy. All four limbs are moving well and there is no cognitive impairment.

You note an ipsilateral (same-sided) facial weakness on the left, and a vesicular looking rash in her left ear canal, which is very sore on examination. She keeps turning her head to right, saying she can’t hear very well out of her left ear since it became sore last week.

Ramsey – Hunt Syndrome – a reactivation of varicella zoster virus in the geniculate ganglion of cranial nerve VII.

Full recovery is more likely if antiviral treatment is started within 72 hours of onset of symptoms. They may also need symptomatic treatment for other symptoms.

More information is available on the excellent DermNet

OSCE of the Week – Cranial Nerves

Use this to practise your abdominal examination. Remember there are resources for lots more system examinations here.




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