A 56 year old woman re-presents to the ED with profound right arm weakness, one day after having been assessed and treated for five days of right shoulder pain. She is a right-handed accountant, who had just been discharged after uncomplicated elective coronary artery grafting, on a background of hypertension and type 2 Diabetes. She had no prior shoulder problems or arthritis.
The pain had initially commenced three days post-op and had been mild but after discharge had worsened, being maximal over the lateral shoulder and unresponsive to oxycodone and paracetamol. There had been no known trauma, other joints involved or associated symptoms. The notes from her previous examination stated that she had been afebrile, with tenderness over the deltoid, full active ROM, and no neurovascular abnormalities in the arm. Investigation with a plain radiograph had been normal, but a shoulder ultrasound had shown the following:
Radiologist report
Appearances strongly suggest a small full thickness tear of the distal supraspinatus tendon measuring approximately 5mm, with substantial bursal thickening. On abduction, there is no obvious impingement and the patient’s pain does not worsen.
Conclusion:
Small full thickness cuff tear with bursal thickening.
Analgesia had been improved by NSAIDs and a sling, and a phone consultation with an Orthopaedic surgeon had led to offer of a steroid/LA injection, but this had been declined by the patient. She had been discharged with the diagnosis of Supraspinatus tendinitis/tear, and an outpatient follow up with the surgeon scheduled for three days later.
When now (unexpectedly) reviewing her in the ED, she is sitting comfortably supporting her right arm with her left, and complains of severe weakness in the arm. She is unable to lift it actively and is pain free with normal observations. Her shoulder to inspection appears normal, but there is no active abduction at all, weak external rotation and flexion, and normal power in extension and internal rotation. There is full passive ROM and neurovascular examination reveals normal pulses, tone, power and reflexes in the limb, with diminished sensation in the right axillary nerve distribution.
These findings are most consistent with loss of axillary nerve function, and I admit to being stumped when confronted with this complete change in her symptoms and findings. Her first presentation had been dominated by pain with no neurological features and the second the reverse. I wondered if she had somehow sustained an injury during her surgery, something akin to “Saturday night palsy”, so discussed it with her surgeon. He had seen CAGs surgery complicated by lower brachial plexus root neuropraxia as a result of retraction of the chest, but he hadn’t seen this kind of shoulder problem before. He suggested I call a neurologist and consider an MRI. The MRI radiologist advised that they would routinely wait six weeks after surgery such as this with sternal wires for non-emergent problems. So I then called the aforementioned orthopaedic surgeon and a neurologist who both immediately knew the diagnosis on the clinical story alone.
This condition is “Brachial neuritis” or “Parsonage-Turner syndrome” an acute idiopathic neuropathy with predominantly motor rather than sensory findings. It presents initially with severe pain in the shoulder followed by weakness affecting various branches of the brachial plexus, with the upper trunk most commonly affected. (anatomy reminder) The condition can be bilateral, and 80% of patients will recover function although this may take two years.
I hadn’t heard of this condition before and a search of the standard EM texts wasn’t so helpful with only Tintinalli including it. I suspect this might be because many of these patients would be referred direct to neurologists rather than ED. I’ve posted this case mainly to share my illumination of something completely new, particularly given the puzzling nature of the presentation (use of dogma no. 3 didn’t help me this time) And the supraspinatus tear? Just an incidental finding that succeeded in throwing us off the scent!
Reference
Wheeless’ textbook of Orthopaedics
One of the neurologists diagnosed this at Charlies last year -- it was the first I’d heard of it then… It was obviously a no brainer for him!
The incidental supraspinatus tear was a heck of a red herring.
C
Great case. Thanks for sharing.