The most common causes of shoulder pain arise from the shoulder itself. These include rotator cuff disorders, arthritis and adhesive capsulitis. However, there are also a number of structures that can cause referred pain to the shoulder.
Dysfunctions of the cervical spine, particularly cervical spondylosis and disc prolapse, may cause shoulder pain. Thoracic outlet syndrome in which either bony or muscular abnormalities cause compression of the brachial plexus may also present as shoulder pain. Occasionally distal arm pathology can radiate back to the shoulder.
Diaphragmatic irritation can result in pain that radiates to the shoulder. This can occur in cases of biliary colic, liver abscess, ectopic pregnancy, pelvic inflammatory disease, subcostal abscess and intestinal perforation. It can also be caused by mesothelioma and pleural secondaries.
Systemic diseases, notably polymyalgia rheumatica, can present with shoulder girdle pain. There is the possibility of involvement of the shoulder region in primary or secondary malignancy. Apical lung cancers, secondaries from distant malignancies and myeloma can all present with shoulder pain. Finally, pain in the mediastinum can result in shoulder pain.
The patient history should include the onset and characteristics of pain and any circumstances in which it changes. Any restriction of movement by pain should be noted as should any history of shoulder trauma.
If referred pain is a possibility, the patient should be asked about pre-existing or new symptoms away from the shoulder. These could be specific, such as abdominal or respiratory symptoms, or more generalised, including fever, sweats and weight loss. In women, a gynaecological history may suggest a pelvic aetiology.
The patient's previous medical history is also important. They should be asked about conditions such as diabetes, respiratory disease, ischaemic heart disease and cancer.
Recent abdominal surgery may increase the possibility of subcostal abscess. The patient's medication may include drugs such as NSAIDs, which increase the risk of intestinal perforation. Patients with a history of smoking and alcohol use should be assessed for respiratory and hepatic disease.
Caution is needed when interpreting history. Although stiffness and pain on movement might reduce the possibility of referred pain, cervical and brachial plexus pathology may be increased by movements. Likewise the absence of central chest pain may not exclude acute MI.
In patients over 65 years, recent onset of pain with bilateral upper arm tenderness and/or morning stiffness may indicate polymyalgia rheumatica.
Local examination should include inspection of the skin, bony contour of the shoulder and chest, and assessment of musculature for wasting. The active, passive and resisted movement at the shoulder should be tested. In addition the supraclavicular fossa should be examined for tumours and lymphadenopathy.
The neck should be examined for range of movement and to see if moving it is painful.
If the patient has pain that radiates below the elbow, Spurlings test is applicable. This involves putting the patient's neck in extension with the head turned towards the affected side. If pressing down on the head increases the symptoms, cervical spondylosis is more likely.
Another useful test is Adson's test for thoracic outlet syndrome. The patient's arm is gradually elevated in an abduction arc with the examiner's fingers held on the patient's radial pulse. As the arm is abducted, patients must turn their head away from the tested side and take a deep breath. If the pulse disappears as the arm is abducted beyond 90 degs, the test is positive for impingement. The test can be repeated with the head turned toward the examined side.
The rest of the examination is dependent on the history but may include a thorough respiratory examination and abdominal palpation for possible sources of diaphragmatic irritation.
If the shoulder pain is thought to come from the neck a cervical X-ray may help with diagnosis, but it is not a reliable way of assessing severity.
If a respiratory cause is suspected then an urgent chest X-ray is needed. This may also be able to detect a cervical rib, if thoracic outlet syndrome is suspected. Other investigations include a FBC test for infection, inflammation and haematological malignancies, and LFTs for hepatic and biliary conditions. In suspected biliary disease, an ultrasound may confirm the presence of gallstones.
In patients aged over 60 with recent onset of shoulder girdle pain, an ESR can exclude polymyalgia rheumatica.
The underlying condition should be treated. Conditions such as MI, suspected ectopic pregnancy, subcostal abscess or intestinal perforation may require immediate admission.
Malignancies should be referred under the two-week rule. Polymyalgia will require treatment with steroids and investigation for thyroid disease. Cervical spondylosis and thoracic outlet syndrome may be treated with analgesia and physiotherapy, although both sometimes require surgical intervention.
Dr Spinks is a GP in Strood, Kent
- Not all shoulder pain comes from damage to the shoulder.
- Common origins of referred pain include the neck, brachial plexus, diaphragm and mediastinum.
- Lung cancer and other malignancies can present as shoulder pain.
- Some causes may need emergency admission or urgent referral.
- Mitchell C, Adebajo A, Hay E et al. Shoulder Pain: diagnosis and management in primary care BMJ 2005; 331: 1,124-8.
- Hosie G. Polymyalgia Rheumatica. Arthritis Research Campaign. 2003: www.arc.org.uk/arthinfo/medpubs/6521/6521.asp
- Woodward T W, Best T M. The painful shoulder: part I. Clinical evaluation. Am Fam Physician 2000; 61: 3,079-88.