Confirmation bias in medical referrals: an unusual presentation of pain at the base of the skull.

A middle-aged woman was referred to the admitting medical team with sudden onset pain at the base of the skull. Initial differentials included subarachnoid haemorrhage and meningitis. Due to the referral of a patient presenting with occipital headache, there was a confirmation bias by the medical team in the initial assessment of this patient, and alternative diagnoses were not considered in the first instance. On review by a medical consultant, pathology in the upper neck was proposed as a cause for the pain. Dedicated CT imaging of the neck revealed acute calcification of the longus colli muscle. This is a usually benign self-limiting condition which is managed in the first instance with non-steroidal anti-inflammatory drugs. Acute calcification of the longus colli is a rare and poorly recognised condition. It should be considered as a potential differential for patients presenting with neck pain, particularly in the presence of odynophagia and mildly elevated inflammatory markers. Cognitive bias should be considered during initial assessment of patients to help reduce premature closure when forming differential diagnoses.