Occupational Overuse Syndrome

Occupational overuse syndrome is a term for work related pain and disability of the upper limbs, neck and shoulders, often diffuse and without a clear structural lesion, in people with repetitive or sustained physical tasks. It is multifactorial and has a strong biopsychosocial component.

Types. Type 1 has a defined condition such as a tendinopathy or nerve entrapment. Type 2 is a diffuse, non-specific regional pain syndrome.

Epidemiology. Reported widely in keyboard, packing, sewing and checkout work, and in musicians and dentists. Women are affected more often.

Risk factors. Repetition, static load, poor workstation set up, tight deadlines, low job control, job dissatisfaction, and poor sleep and mood.

Course. Many settle with early task change; some become chronic with widespread pain and work absence.

Pathophysiology.

Sustained muscle activity and microtrauma cause local muscle overload and tendon strain. Central pain processing becomes sensitised in chronic cases.

Psychosocial stress increases muscle tension and pain perception, and sustains disability.

• Aching, burning or fatigue in the forearm, wrist, shoulder or neck during and after tasks.
• Tenderness over muscles and tendons, reduced grip and endurance.
• Sleep disturbance, anxiety and low mood in chronic cases.
• Examination may be normal apart from tenderness.

Red flags.

• Constant night pain, fever, weight loss or a history of cancer.
• Progressive weakness, wasting or myelopathic signs.
• Marked depression or suicidal thoughts.

• Task and workplace history, symptom pattern, psychosocial factors and prior treatment.
• Examination to exclude specific lesions, with neurological and shoulder assessment.
• Investigations only when a specific cause is suspected: blood tests, ultrasound, nerve conduction studies.
• Screen mood and sleep; assess work ability.

Differential diagnosis. Specific tendinopathies, nerve entrapment, cervical radiculopathy, thoracic outlet syndrome, inflammatory arthritis, fibromyalgia, hypothyroidism, depression with somatic pain.

• Early, graded task modification and workstation ergonomics; keep working in modified duties where possible.
• Graded exercise, physiotherapy and pain education; cognitive behavioural therapy for persistent pain and distress.
• Paracetamol 1 g orally every 6 hours as needed, maximum 4 g in 24 hours (3 g if under 50 kg, chronic alcohol excess or liver disease), for the shortest period that controls pain. Monitor liver function with prolonged use. Reduce dose in hepatic impairment; extend dosing interval when eGFR is under 30.
• Persistent pain with sleep disturbance: amitriptyline 10 mg orally at night, increased by 10 mg every 1 to 2 weeks as tolerated to 30 to 50 mg at night, maximum 75 mg at night. Review at 6 to 8 weeks and stop if there is no benefit. Monitor sedation, anticholinergic effects, postural hypotension and mood; baseline ECG when over 40 years or with cardiac risk. Avoid after recent myocardial infarction, with arrhythmia, in angle closure glaucoma or urinary retention, and with other serotonergic drugs. Start at 10 mg and cap at 50 mg in older adults; reduce dose in hepatic impairment; no renal adjustment. Evidence for benefit is limited.
• Avoid opioids and prolonged rest.

Monitoring. Review at 4 to 6 weeks, then every 3 months; track pain, function and work status.

Referral and escalation. Occupational physician and physiotherapy; pain clinic or psychology for chronic disabling pain; urgent review for red flags; notification and compensation where required.

Special groups. Pregnancy: avoid amitriptyline unless benefit outweighs risk. Older adults: lowest dose and slow titration.