It has been four years since the Supreme Court's judgment in Montgomery v Lanarkshire Health Board 2015 SC (UKSC) 63 and there is still satellite litigation on exactly how the decision should be interpreted. In Johnstone v NHS Grampian [2019] CSOH 90 the court has once again determined that what treatment options are "reasonable" is to be judged using the ordinary test for medical negligence and not by what a patient would consider reasonable.

Mr Johnstone has acromegaly, a syndrome where the pituitary gland produces too much growth hormone. In 2010 his growth hormone levels had risen to double normal levels. An MDT meeting studied Mr Johnstone's MRI scan and decided that he had a tumour in his pituitary gland. They recommended active treatment.

The pursuer met Mr Kamel who discussed the treatment options open to him. The outcome was that the pursuer should undergo further surgery, which he did in 2011. Following the operation Mr Johnstone developed a post-operative leak of CSF and meningitis.

Mr Johnstone alleged he was not fully informed of all possible treatment options. He said he had not been warned of the potentially life-threatening risks of surgery. He had not been given the option of no treatment and would undoubtedly have chosen radiosurgery, not surgery, if he had known it was risk-free. As a result he had not been able to give informed consent.

Mr Kamel denied this. His said that he had thoroughly explained all available options, including doing nothing.

The first issue was a factual one. There was a dispute between Mr Johnstone and Mr Kamel about what risks were explained. The evidence of Mr Johnstone, his wife, and Mr Kamel all differed. The court favoured the contemporaneous note dictated by Mr Kamel following his meeting with the pursuer prior to the 2011 surgery. This note was held to be a fair summary of the meeting and set out treatment options and associated risks and benefits. This included the risk of post-operative CSF leakage and meningitis.

The court also found that Mr Kamel had given the pursuer the option of no treatment. However, if he had not, he would have been under no obligation to do so. The MDT meeting had determined that active treatment was necessary. Mr Johnstone did not argue, on a Hunter v Hanley basis, that no ordinarily competent MDT exercising reasonable skill and care could have reached that decision. As active treatment was necessary the option of no treatment was not a reasonable option.

It is now beyond doubt that a patient must be informed of all reasonable treatment options. But it is also equally clear that what counts as "reasonable" is determined by a reasonable body of medical opinion. The role of the expert in consent cases is not dead.

The case also highlights the importance of detailed contemporaneous clinical records. While recent case law indicates that such records will not always be preferred, a doctor's evidence of discussions is going to have much more weight when backed up in writing.