Hand pain: red flags and pitfalls

Introduction

Many pathologies can cause pain in the hand and a review article inevitably risks turning into a long list. Causes of pain are categorised below, initially by severity within pathologic groups for example infective or neurologic, to establish a core knowledge base. Careful history and a methodical examination of the painful hand will aid the physician in diagnosis. Caution must be exercised with any history of trauma as it is easy to miss a fracture or divided tendon with inevitable medicolegal consequences.

Differential diagnosis

Severe pain may be caused by infection, nerve entrapment, acute inflammatory or degenerative joint disease.

Infection

Infection generally presents acutely with local signs including redness, swelling and markedly decreased active and passive range of motion in digit or joint. In addition, there may be signs of systemic upset. Pus within a space such as joint (septic arthritis), flexor tendon sheath or within a fascial compartment is exquisitely painful and requires urgent surgical intervention.

Nerve entrapment

Classically carpal tunnel syndrome (median nerve entrapment at the level of the wrist) causes night symptoms such as paraesthesia. Patients wake and shake their hands or lower them out of bed in an effort to relieve symptoms. During the day elevation, for example whilst driving, can cause exacerbation of symptoms and the pain can also travel into the forearm or even to the shoulder. This is the commonest form of compression neuropathy with an incidence of 3% across the population.¹ It regularly occurs alongside other hand pathologies eg. base of thumb osteoarthritis.²

As the neuropathy worsens, fine manipulative tasks become more difficult (eg. picking up coins or doing up buttons) and sensibility to the thumb, index and middle finger is permanently altered. Possible treatments for carpal tunnel syndrome are splints, steroid injection or surgical decompression. In practice surgical decompression (usually under local anaesthesia) gives excellent long term relief to the majority,³ with splints and injection used in mild cases.

Ulnar nerve symptoms generally caused by cubital tunnel syndrome (entrapment of the ulnar nerve at the elbow – the second most common compression neuropathy) causes numbness and paraesthesia in the little and ring finger with eventual wasting of the small muscles of the hand leading to loss of dexterity, weakened key pinch and ‘clawing’ hyperextension of the ring and little finger metacarpophalangeal joints with proximal interphalangeal joint flexion.

Inflammatory arthropathy

Inflammatory change is most often gout or pseudogout related, the latter classically affecting the wrist. It is hard to differentiate from infection locally (inflamed wrist with redness and decreased movement) although gout won’t show systemic signs. Joint aspiration with microscopic examination of synovial fluid can prove the diagnosis showing uric acid crystals present in gout and calcium pyrophosphate crystals in pseudogout. Gout can affect distal interphalangeal joints with x-rays often confirming joint destruction, and white deposits (tophi) may form.

Rheumatoid arthritis may affect any synovial lined area (joints, flexor or extensor tendons). Its first presentation is variable but synovial proliferation leads to deformity of the wrist and digits and occasionally tendon rupture such as extensor tendons to little, ring finger and thumb and flexor tendon to the thumb. Extensor tendon rupture presents with a ‘dropped finger’ and all should be referred acutely to a hand surgeon.

Stenosing tenosynovitis

Also known as De Quervain’s disease, this inflammatory thickening of the tendon sheath affects the long extensor and abductor of the thumb in the first extensor compartment of the wrist. It typically causes severe pain and swelling along the radial side of the wrist. Treatment involves restriction of movement with splints, steroid injection and, in the more severe cases, surgical decompression.

Osteoarthritis

Primary osteoarthritis affects distal interphalangeal joints with classical nodular swellings (Heberdens’ nodes) which are painful. Degenerative change weakens the joint capsule resulting in a mucous cyst and causing nail changes. The associated deformity represents the bane of many an ageing female patient’s hands. Proximal interphalangeal joint involvement may be isolated but quite disabling. Wrist degenerative change is often secondary to previous injury such as scaphoid non-union or scapholunate ligament disruption. However a minor injury can cause a sudden symptomatic increase although x-rays reveal long standing change.

Most commonly it is the base of thumb that becomes painful (1st carpometacarpal joint) with decreased pinch strength and deformity affecting a third of post menopausal female patients but only 6% of men.^4,5

Hand trauma

Sudden onset pain in the hand is always a cause for concern. Where associated with blunt or sharp trauma, fracture or division of tendon, nerve or ligament must be considered. Sharp trauma can be especially misleading as what may superficially appear to be a tiny cut misleads as to the depth of penetration and possibility of tendon or nerve division. Joint penetration (eg. punch injury over the metacarpal joint) can cause bacterial inoculation and septic arthritis.

Other painful problems include a diverse range of conditions. Dupuytrens disease which is ultimately a fibrous contracture of the palmar fascia, often has tender nodules initially forming in the palm and this affects grip.

Triggering of a digit caused by thickening of the annular pulley (entrance of the tunnel system containing the digital flexor tendons) is a common diagnosis causing mechanical symptoms.

The locked digit (in flexion) needs to be forcibly straightened to recover movement and this action is painful. It is often worse first thing in the morning. Early onset, especially in diabetic or rheumatoid hands is marked by severe tenderness over with steroid the base of the fingers (palmar aspect) where isolated synovitis is present around the flexor tendon at the tunnel entrance.

Complex regional pain syndrome can affect the hand after surgery, closed distal radial fracture or even a minor injury. Allodynia (disproportionate pain), redness and hyperesthesia with swelling and stiffness of the whole joint are typical features.⁶ Early diagnosis with effective pain management and referral to a hand therapist is vital and it is essential to avoid aggravating exercises and activities.

History and examination

With so many possible diagnoses, careful history looking at speed of onset, site of pain and exacerbating/relieving factors must be considered. Examination requires careful palpation correlated with knowledge of basic anatomy. Remember, the examiners thumb tip is larger than some carpal bones so be specific as possible when examining the carpus-tenderness over the 1st carpometacarpal joint or just proximal and dorsal, the scaphotrapezial joint, may help distinguish osteoarthritis of these joints.

After careful palpation of bony structure to reveal bone or joint pathology, thoughts should turn to the ligaments and tendons. Thumb stability is vital to pinch strength and this can be compromised by the acute injury such as ulnar collateral injury at the metacarpophalangeal joint (skiers thumb) or degenerative changes. The long flexor tendons cause flexion of the distal and proximal interphalangeal joints of the fingers with one to the thumb interphalangeal joint. Open or closed injury may cause tendon division (eg. forced extension of a finger distal interphalangeal joint as it flexes may lead to flexor digitorum avulsion ‘rugger jersey finger’.

Tendons should be tested methodically with resisted flexion at thumb interphalangeal and finger distal interphalangeal joints. The fingers should then be held in extension to block the effect of flexor digitorum profundus releasing one finger at a time to check for flexor digitorum superficialis function at the proximal interphalangeal joint.

The extensors can also be damaged in closed injuries – commonly at the distal interphalangeal joint where inability to actively extend

represents a mallet deformity, or at the proximal interphalangeal joint where the central slip insertion can be avulsed producing a later Boutonniere deformity (flexion at the PIPJ, extension at the DIPJ). These injuries are often missed and once joints stiffen become very difficult to treat.

The Finkelstein’s provocative test is a useful diagnostic tool for tenosynovitis. Grasping the thumb and ulnar deviating the hand sharply causes pain over the radial styloid.

Nerve function is next to be tested with a sensory and motor test for the median and ulna nerves. The median nerve supplies sensation to the radial three digits and innervates the abductor pollicis brevis muscle (found at the base of the thumb, palmar aspect), which may be wasted in severe carpal tunnel syndrome.

The ulnar nerve supplies sensation to the little finger and the majority of the small muscles of the hand (intrinsics) tested by asking the patient to spread or abduct their fingers against resistance. The radial nerve has no motor power in the hand supplying sensation to the dorsoradial aspect.

It is important to remember neck involvement as the cause of more distal presenting symptoms. A radicular pattern of involvement can point to a more proximal underlying cause such as cervical nerve root entrapment.

A localised painful swelling with a positive Tinel sign may indicate a nerve sheath tumour, typically lying within the digital nerves.

Finally consider vascularity. Raynaud’s phenomenon is vasospasm of the digit with the marked colour change and pain with reperfusion. It may be primary (Raynaud’s disease) or secondary when there is an underlying cause eg. Embolic and occlusive disease.⁷ Rarely an iatrogenic arteriovenous shunt for dialysis can lead to ‘steal’ syndrome with pain, pulp tip necrosis and poor wound healing due to diversion of the hand’s arterial inflow.

Investigations

Plain x-ray of the hand and wrist is probably the most helpful aid for the diagnosis and management of the degenerate hand. Getting the correct views is the key. Two views for trauma is ideal and in finger trauma it is mandatory to ask for a true lateral to exclude fractures and joint subluxation. When dealing with a suspected scaphoid fracture, because of its twisted shape, this nasty little bone must be imaged with a specific sequence of views as all too easily a fracture line can be missed.

Ultrasound is a useful modality to help diagnose closed injuries for example in cases of tendon avulsions and ligamentous ruptures.

Nerve conduction studies can be very useful to confirm and grade carpal and cubital tunnel syndrome especially where symptoms are difficult to interpret.

Blood tests include white cell count and inflammatory markers for suppurative infection and inflammatory conditions. Don’t forget to check thyroid levels as a possible cause of carpal tunnel syndrome⁸ and consider late onset diabetes or inflammatory arthropathy in those presenting with multiple trigger digits.⁹

Top tips

• Treat all trauma with great suspicion and have a low threshold for an x-ray. It is surprisingly easy to miss a dislocated or subluxed finger joint.
• Even the humble mallet finger, an extension lag of the distal interphalangeal joint, may be associated with a bony avulsion fracture and subluxation that needs surgical intervention.
• Even the smallest laceration may cause an underlying tendon or nerve injury – test any structure that runs in the vicinity.
• Any hand infection left untreated can cause stiffness and compromised function long term. Be aggressive with treatment and refer early.
• Trigger finger is common but occasionally confused with extensor tendon subluxation where a finger cannot be extended without assistance – watch the dorsum of the metacarpophalangeal joint carefully as the tendon ‘jumps’ back to its normal position. Unlike a trigger finger, the proximal interphalangeal joint is held straight.

Red flags

• Acute redness, swelling, pain on passive stretch and loss of movement due to a digital flexor tendon sheath infection requiring urgent surgical debridement.
• Failure to actively flex or extend a passively mobile joint means a tendon rupture which could be ‘closed’ ie. No sharp trauma.
• Glomus tumours are a rare cause of intense pain in the finger tip and under the nail. A bluish discoloration may be present but often there is nothing to find on clinical examination. They are cold intolerant and MRI with gadolinium will reveal them.¹⁰
• A rapidly expanding painful lump in the hand may indicate a malignant process (eg. Sarcoma) and needs urgent referral.
• Bone destruction can occur through primary or secondary tumour (eg. lung metastasis) and is painful.
• Scaphoid tenderness always mandates an x-ray with an appropriate request giving the radiologist as much information as possible eg. date of injury.

Case report

A 56 year old female shop assistant presented to her GP with pain in her right dominant thumb of gradual onset over the last 18 months. Examination found tenderness at the base of the thumb and difficulty with pinch grip due to pain. A diagnosis of primary osteoarthritis of the thumb base was made, analgesics were prescribed and she was provided with a removable thumb splint. Four weeks later she returned to report that her pain was slightly improved but she experienced tingling in the thumb and index finger. Further examination revealed subtle wasting of the thenar eminence and a positive Phalens test (maintained flexion of the wrist causing worsening of median nerve paraesthesia). The pain remained at the base of the thumb.

The patient was referred with a diagnosis of carpal tunnel syndrome and thumb base osteoarthritis. On review in clinic the symptoms and signs of carpal tunnel were confirmed but the base of thumb pain was more extensive and X-rays showed not just thumb 1st carpometacarpal (1st CMC) but also scaphotrapezialtrapezoid (STT) joint osteoarthritis. The carpal tunnel syndrome was confirmed by nerve conduction studies.

Because work was a priority this patient chose to have carpal tunnel decompression under local anaesthetic and injection of the 1st CMC and STT joints with steroid under image intensifier guidance at the same time. She returned to work two weeks later. In future she may require surgery for the thumb osteoarthritis but recovery is prolonged.

This case illustrates that dual pathology can exist in the hand and treatment depends on individuals needs.

Conclusion

The hand is a complex functional unit that must be approached with knowledge of the conditions that can disable it and be examined with attention to anatomic detail. Simplify by examining each anatomic group ”bone, joint, tendon, nerve and vessels. Delay in diagnosis may significantly affect final outcome so if in doubt seek urgent advice.

Key points

• Careful history and a methodical examination of the painful hand will aid the physician in diagnosis.
• The symptoms presenting in the hand may be reflective of a systemic disease
• Severe pain may be caused by infection, nerve entrapment, acute inflammatory or degenerative joint disease.
• Possible treatments for carpal tunnel syndrome are splints, steroid injection or surgical decompression.
• Inflammatory change is most often gout or pseudogout related, the latter classically affecting the wrist.

---

Mr Shakeel Dustagheer  Hand Fellow, Norfolk and Norwich University Hospital NHS Trust

Mr Adrian Chojnowski Consultant Orthopaedic Surgeon, Norfolk and Norwich University Hospital NHS Trust

Email [email protected]

---

References

1. Atroshi I, Gummesson C, Johnsson R, et al. Prevalence of carpal tunnel syndrome in a general population. JAMA 1999; 282(2): 153-58
2. Florack TM, Miller RJ, Pellegrini VD, et al. The prevalence of carpal tunnel syndrome in patients with basal joint arthritis of the thumb. J Hand Surg Am 1992; 17(4): 624-30
3. Katz JN, Keller RB, Simmons BP, et al. Maine Carpal Tunnel Study: outcomes of operative and nonoperative therapy for carpal tunnel syndrome in a communitybased cohort. J Hand Surg Am 1998 Jul; 23(4): 697-710
4. Armstrong AL, Hunter JB, Davis TR. The prevalence of degenerative arthritis of the base of the thumb in post-menopausal women. J Hand Surg Br 1994; 19(3): 340-41
5. Haara MM, Heliovaara M, Kroger H, et al. Osteoarthritis in the carpometacarpal joint of the thumb. Prevalence and associations with disability and mortality. J Bone Joint Surg Am 2004; 86-A(7): 1452-57
6. Soucacos PN, Diznitsas LA, Beris AE, et al. Reflex sympathetic dystrophy of the upper extremity. Clinical features and response to multimodal management. Hand Clin 1997; 13(3): 339-54
7. Koman LA, Ruch DS, Paterson Smith B, Smith TL. Vascular Disorders Green’s Operative Hand Surgery 2005; 2303-2304
8. Roquer J, Cano JF. Carpal tunnel syndrome and hyperthyroidism. A prospective study. Acta Neurol Scand 1993; 88(2): 149-52
9. Griggs SM, Weiss AP, Lane LB, et al. Treatment of trigger finger in patients with diabetes mellitus. J Hand Surg Am 1995; 20(5): 787-89
10. Walsh JJ, Eady JL. Vascular tumors. Hand Clin 2004; 20(3): 261-vi.