Clinical presentation
How does Parsonage Turner Syndrome clinically present?
Parsonage Turner syndrome typically presents as severe shoulder and arm pain that starts over hours or on waking and lasts for weeks. It is associated with sensory symptoms, muscle weakness and atrophy. There is often an associated prodromal viral illness or other triggering factors such as surgery, childbirth or vaccination.
Clinical presentation of many patients (n=199) with idiopathic form of Parsonage-Turner syndrome (hereditary, n=47) has been studied by Nens van Alfen et al, Brain, 2006.1 The symptoms, course and prognosis of this disorder provides greater insight into the broad clinical spectrum of the disorder. Generally, the course of the patients’ pain manifests itself in three consecutive phases occurring before and alongside muscle weakness and atrophy.
Phases of pain
1. Acute painful phase
· Pain can start suddenly (within a few hours) within the shoulder region or the upper extremity, occurring mostly in one extremity (71.5%) but it can occur bilaterally (28.5%).
· Severe pain (median numeral rating scale pain of 8 at onset, 9 and peak).
· Pain worse at night and caused sleep disturbances in 93.5%.
· Pain associated with increased mechanical sensitivity of the affected nerves in 80% of men, 97.4% women.
· Overall median duration of the pain was 19.5 days, lasting twice as long in men (median 45 days) versus 21 days in women.
2. Continuous neuropathic painful phase
· Present in 76.5% of patients
· Neuropathic stabbing or shooting pains usually elicited by movement or lying on the affected limb.
· Often lasting from a few weeks to several months.
3. Persisting Musculoskeletal type of pain phase
· Present in 65.1% of patients
· Usually localized to the origin or insertion of the paretic or compensating muscles, especially in the periscapular, cervical and occipital regions.
· Pain can also develop because of glenohumeral joint pathology associated with paresis of rotator cuff muscles, decreased movement or frozen shoulder development.
On follow-up, 29% patients developed chronic, usually therapy-resistant, continuous pains in the previously affected region.
Muscular Weakness and Atrophy
· Average time from pain to onset of weakness was 14 days in men and 8 days in women (not statistically significant).
· First signs of weakness appeared:
o first 24hours (34%)
o 1 to 7 days (39%)
o 1 to 2 weeks (14%)
o More than 2 weeks (13%) [in patients with typical onset of pain]
· Paresis severity progressed further in 30% cases, developing over the following days (28%), weeks (53%) and months (19%).
· Distribution of paresis of the upper part of the brachial plexus was most common (71%), either with involvement of the long thoracic nerve (50%) or without (21%).
· Females have greater involvement of the middle and lower parts of the brachial plexus than males (23% vs 10%).
· Frequency of the muscles affected:
o Infraspinatus (72%)
o Serratus anterior (70%)
o Supraspinatus (66%)
o Biceps Brachii (61%)
o Wrist extensors (47%)
o Deltoid (46%)
o Finger extensors (36%)
o Thumb extensors (27%)
o Trapezius (20%)
o Pectoralis major (15%)
o Sternocleidomastoid (7%)
Sensory Symptoms
· Sensory symptoms reported by 69% patients and found on examination in 78% patients.
· Hypaesthesia was the most common complaint (46%), followed by a combination of paraesthesia and hypaesthesia in 39%, and paraesthesia only in 14%.
· Lateral shoulder and/or arm most common (49%), fingers and hand (21%), medial forearm (18%), neck, back and scapula (6%) and other (6%).
References
1. Nens van Alfen & Baziel G. M. van Engelen. The clinical spectrum of neuralgic amyotrophy in 246 cases, Brain, 2006, 129, 438–450. https://doi.org/10.1093/brain/awh722