Mr B, a 42-year-old builder, attended his GP, Dr S, with a three-week history of back pain and left sided sciatica. Dr S found nothing of concern on further questioning or examination, so made a referral for physiotherapy and recommended ibuprofen. Over the next few weeks the pain increased and the patient required diclofenac and cocodamol to control his symptoms.

Two months later, while still waiting for his physiotherapy appointment, the pain got so bad that Mr B called an ambulance and was taken to the Emergency Department (ED), where he was found to have a slight left foot drop and bilateral straight leg raising of 45 degrees. Mr B’s neurology was not examined. The ED doctor thought that this was not sciatica but simple back pain made worse by moving Mr B’s legs. Mr B was sent home with diazepam.

One week later, the pain was even worse and there was now intermittent numbness in both buttocks. Mr B called the out-of-hours GP service and was seen at home by Dr T. He told Dr T that he was able to pass small amounts of urine, and Dr T also recorded “no saddle anaesthesia”. Dr T carried out a very brief examination of the legs which was unremarkable, started tramadol, and advised Mr B to keep active and see his own GP the following day.

Mr B was reviewed by Dr S the next day, who again recorded in the notes: “No red flags, no loss of bowel or bladder function. No saddle anaesthesia.”

Dr S gave Mr B a diclofenac injection and arranged an MRI scan. He too only carried out a very brief examination of the back and legs.

Two days later, due to intolerable pain, Mr B was on his way to the ED again when he suffered urinary incontinence in the ambulance. On admission, he had an MRI scan that showed a large L4/5 central disc pressing on the cauda equina.

Mr B underwent surgical decompression the next day but was left with bilateral foot drop, requiring the use of a wheelchair, and bowel, bladder and sexual dysfunction.

Mr B brought a claim against all the doctors involved in his care. He alleged that they had failed to take a proper history and perform an adequate examination, including assessment of perineal sensation and anal tone. The claim also alleged that they did not give proper regard to bilateral and worsening pain and buttock numbness, and did not refer for urgent assessment.

Expert opinion

Medical Protection instructed an expert GP who was critical of the care provided by both general practitioners. She opined that Dr T did not carry out an adequate assessment after the report of intermittent buttock numbness, and that Dr S conducted a “very severely substandard” examination the next day.

Emergency medicine and orthopaedic experts concluded that the ED doctor’s assessment had been inadequate and were critical of the delay before decompression. They also stated that if Drs S or T had assessed Mr B more thoroughly they would likely have found perineal numbness and/or urinary retention, and the resulting emergency decompression would have left Mr B in a much better condition.

On the basis of the expert opinion, the case was deemed indefensible and was settled for a high sum, shared equally between the hospital, Dr S and Dr T.

Learning points

• Even when referral to physiotherapy has already been made, keep a low threshold for reassessment if things change.
• Issuing analgesia, especially increasing the strength, is an opportunity for reassessment.
• Do not assume that the doctor who saw the patient before you has carried out an adequate assessment, even though nothing might have changed.
• If you ask a patient if they have saddle anaesthesia, make sure they know exactly what that is. It might be useful to ask about rectal function, numbness between the legs or around genitals and anus, and if they have any difficulty getting an erection. 
• Any suggestion of perineal numbness or urinary symptoms mandates a thorough assessment of both. Don’t forget that urinary tract infections can be caused by retention.
• Giving patients information about the red flags for cauda equina in writing can improve safety netting, however it is no substitute for discussing them with the patient and explaining how the different red flags can present and what the symptoms may mean.