Footnotes

• Contributors The authors NW and CR were involved clinically in the case. The concept for this work was envisaged by SC. The letter was first drafted by MM. The algorithm was created by SC and CR. All authors were involved in editing and reviewed the final version of the letter. The author SC will act as guarantor for this work.

• Competing interests None.

• Patient consent Obtained.

• Provenance and peer review Not commissioned; internally peer reviewed.