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Inflammatory posterior interosseous nerve palsy in a patient with psoriatic arthropathy
Journal of Plastic, Reconstructive & Aesthetic Surgery (2011) 64, e205ee207
CASE REPORT
Inflammatory posterior interosseous nerve palsy in a patient with psoriatic arthropathy Erden Ali a,*, Robert Colac ¸o d ¸o b, Patrick Gillespie c, C. Bernard Colac a
Department of Plastic and Reconstructive Surgery, The Lister Hospital, Stevenage, UK University of Bristol School of Medicine, UK c Department of Plastic & Reconstructive Surgery, Addenbrooke’s University Hospital, Cambridge, UK d Rheumatology Unit, Central Middlesex Hospital, Park Royal, London, UK b
Received 9 February 2011; accepted 27 March 2011
KEYWORDS Posterior interosseus nerve; Nerve palsy; Psoriasis; Psoriatic arthropathy; Mononeuritis; Peripheral mononeuropathy
Summary Psoriasis is a chronic, relapsing, inflammatory skin disorder with a strong genetic basis. Five patterns of psoriatic arthritis have been identified: asymmetrical oligoarticular arthritis, symmetrical polyarthritis, distal interphalangeal arthropathy, arthritis mutilans and spondylitis with or without sacroiliitis. Extra-articular disease is uncommon. We report a rare case of an inflammatory posterior interosseus nerve palsy in a patient with known psoriatic arthropathy, where investigation warranted medical treatment over a surgical approach. The commonest cause of posterior interosseus nerve palsy is entrapment at the proximal forearm. Other possible aetiologies include extension of elbow synovitis as described in rheumatoid arthritis, trauma eg. Monteggia fractures, tumours and iatrogenic injuries. We discuss the diagnostic dilemma and the management issues for upper limb surgeons. ª 2011 British Association of Plastic, Reconstructive and Aesthetic Surgeons. Published by Elsevier Ltd. All rights reserved.
Introduction There are several distinctive clinical variants of psoriasis with the plaque type being the most common. Up to 10e20% of patients with plaque psoriasis also experience psoriatic arthritis (PsA).
PsA is an inflammatory seronegative spondyloarthropathy. Joint and skin symptoms occur simultaneously in approximately 15% of people with the disease. In 60% of people the cutaneous manifestations precede the arthritis and in 25%, of those with psoriasis, the arthritis appears first. PsA may mimic rheumatoid arthritis or ankylosing spondylitis.
* Corresponding author. Tel.: þ44 1438 781 535; fax: þ44 1438 284 660. E-mail address: [email protected] (E. Ali). 1748-6815/$ - see front matter ª 2011 British Association of Plastic, Reconstructive and Aesthetic Surgeons. Published by Elsevier Ltd. All rights reserved. doi:10.1016/j.bjps.2011.03.039
e206
E. Ali et al.
A strong genetic predisposition does exist. Approximately eight genetic susceptibility loci (PSORS I-VIII) have been observed.1 The most important locus is considered to be psoriasis susceptibility 1 (PSORS1) locus located on chromosome 6 and can be seen in up to 50% of psoriasis cases.2 Extra-articular disease includes neuropathies, but are less common than in seropositive rheumatoid arthritis. In this case we describe a peripheral mononeuritis of the posterior interosseous nerve (PIN). The PIN is the deep motor branch of the radial nerve and supplies all the extrinsic wrist extensors except extensor carpi radialis longus. Compression or injury to the radial nerve can occur at any point along its course from the brachial plexus. It is thought that compression to the PIN occurs after branches to the wrist extensors and the radial sensory nerve have emerged. Most commonly, this occurs at the supinator muscle at the proximal forearm.3 Clinically, a palsy of the PIN usually presents with weakness or paralysis of the wrist and digital extensors.
Case report We report the case of a 56 year old man who was diagnosed with mild skin psoriasis and psoriatic arthropathy twenty years ago. He had tried several disease modifying antirheumatic drugs and was found to be intolerant of azathioprine, sulfasalazine and methotrexate. He was being maintained on leflunomide 10 mg once daily but was still restricted with neck stiffness and persistent synovitis at metacarpophalangeal joints, proximal interphalangeal joints and both elbows. In April 2008, the patient gradually became unable to extend his right wrist (Figure 1A,B,C). The patient was seen by the plastic surgery department where clinical examination suggested a PIN palsy. Movement at the elbow joint had not changed and the patient did not describe any new or worsening neck symptoms. Exploration was delayed until further investigations were performed in order to ensure that the aetiology was established before potentially unnecessary operative intervention was undertaken. The patient was then referred to the rheumatology department where needle electromyography (EMG) was requested and confirmed the diagnosis. Biceps, triceps, flexor digitorum superficialis (FDS) and extensor carpi radialis longus (ECRL) were used as controls and demonstrated normal motor units and recruitment patterns. Only single motor unit activity was demonstrated in extensor digitorum communis, extensor indicis and extensor carpi ulnaris characterising the lesion as severe. Magnetic resonance imaging (MRI) was then used to exclude any possible nerve entrapment at the cervical spine, elbow or wrist, this combined with the EMG results attributed the aetiology to a vasculitis and not nerve compression. The patient was then managed as having an inflammatory mononeuritis (presumed secondary to microvascular inflammation) of the PIN. In June 2008, infliximab (anti tumour necrosis factor (TNF) therapy) was introduced as a further immunosuppressive therapy to leflunomide. The patient was seen in the out-patient department in August 2008 after having completed three courses of anti-TNF therapy where it was
Figure 1 Images to demonstrate the patient’s inability to fully extend the right wrist. (A) Right lateral view comparing extension of the left and right wrists, (B) lateral/oblique view of the right wrist, (C) oblique view of the right wrist. In all the images, the patient’s psoriatic rash is visible.
revealed he had improved wrist extension and had returned to playing golf. There was a gradual improvement in wrist extension and over a period of approximately eighteen months he had progressed to almost full wrist extension. At present, the patient has 0e5 of extensor lag and has improved significantly with anti-TNF medication and hand
Inflammatory posterior interosseous nerve palsy in a patient with psoriatic arthropathy therapy. Grip strength and TIP-pinch strength are comparable with the contra- lateral side. The patient does not report any functional deficit but did develop an exacerbation of the cutaneous manifestation of the disease post medical treatment with infliximab.4 This subsequently improved with oral steroids.
Discussion After its emergence from the supinator muscle, the PIN may be compressed before it bifurcates into medial and lateral branches. This would lead to a complete paralysis of digital extensors and manifest clinically with dorsoradial deviation of the wrist on attempted extension, secondary to extensor carpi ulnaris paralysis and preservation of ECRL function. If compression occurs after the bifurcation, selective paralysis of muscles occurs. Compression of the medial branch causes paralysis of the extensor carpi ulnaris, extensor digiti quinti, and extensor digitorum communis. Compression of the lateral branch causes paralysis of the abductor pollicis longus, extensor pollicis brevis, extensor pollicis longus, and extensor indicis proprius. The commonest cause of a PIN palsy is compression and this was excluded by MRI. History and electrophysiological studies differentiate between nerve entrapment and a vasculitis. Acute onset of paralysis often associated with neuropathic pain and isolated muscle fasciculations compared with a more progressive history are indicative of a vasculitic lesion or nerve compression respectively.5 With a vasculitis, EMG performed up to 3 weeks from the onset of symptoms shows normal conduction velocities and reduced response amplitudes. EMG performed at a later stage shows fibrillations and polyphasic motor unit potentials due to collateral reinnervation. Conversely, in cases of compression, distal axonal degeneration is difficult to elicit and conduction velocities are slowed.5 The palsy was considered inflammatory in origin and recovery of extensor function occurred during treatment with anti-TNF therapy. It should be noted that etanercept (anti-TNF therapy) has conversely been linked with development of a peripheral mononeuropathy within the context of an inflammatory arthritis.6 Differentials may include a focal myopathy7 or more commonly an extensor tendon rupture, which historically may have warranted radiographic investigations with an injection of Renograffin R8 but now can be excluded with MRI. Rheumatoid arthritis has previously been reported as the cause of PIN palsy due to synovitis of the extensor tendon sheath or from a neuropathy caused by occlusion of the epineural arteries, leading to ischaemic nerve lesions after fibrinoid necrosis and inflammatory infiltration of vessel walls has occurred.8e13 Although there are reports in the literature of inflammatory psoriatic polyneuropathies,14 we believe this is the first report of a psoriatic mononeuritis, not related to compression neuropathy. In the reported case, clinical examination and further investigations excluded compression and medical treatment was instigated. Despite a cutaneous exacerbation of the underlying disease, most likely related to the management of the mononeuropathy, the patient has shown excellent recovery of function.
e207
We report the case of an inflammatory PIN palsy in a patient with known psoriatic arthropathy where the symptoms improved with immunosuppressive therapy. This case highlights that psoriatic arthropathy may be associated with extra-articular disease. When compression of the PIN is diagnosed, surgical exploration and release of the nerve is the commonest treatment for simple mechanical compression. The literature for patients with idiopathic PIN palsy suggests waiting for approximately 6 months before proceeding to exploration. This case highlights the diagnostic dilemma posed to plastic surgeons in a patient who presents with a clinical PIN palsy on a background of inflammatory arthropathy. Differential diagnoses includes extensor dysfunction/rupture which warrants exploration and repair however imaging techniques and investigations such as EMG ensure a diagnosis is established prior to unnecessary surgery.
Conflict of interest statement None.
Acknowledgments The authors would like to thank Professor Jagdeep Nanchahal (Imperial College Health Care) for providing patient data.
References 1. American Academy of Dermatology. Guidelines of care for the management of psoriasis and psoriatic arthritis -Section 1. Overview of psoriasis and guidelines of care for the treatment of psoriasis with biologics; 2008. 2. Scho ¨n MP, Boehncke WH. Psoriasis. NEJM 2005;352:1899e912. 3. Dang AC, Rodner CM. Unusual compression neuropathies of the forearm, part I: radial nerve. J Hand Surg Am 2009;34(10):1906e14. 4. Di Lernia V, Guareschi E. Successful treatment of hand and foot psoriasis with infliximab. Dermatol Online J 2010;16(7):8. 5. Chan JK, Kennett R, Smith G. Posterior interosseous nerve palsy in rheumatoid arthritis: case report and literature review. J Plast Reconstr Aesthet Surg 2009;62(12):e556e60. 6. Hanaoka BY, Libecco J, Rensel M, Hajj-Ali RA. Peripheral mononeuropathy with etanercept use: case report. J Rheumatol 2008;35(1):182. 7. Erdem S, Demerci M, Tan E. Focal myopathy mimicking posterior interosseous nerve syndrome. Muscle Nerve 2001;24:969e72. 8. Chang LW, Gowans JDC, Granger CV, Millender LH. Entrapment neuropathy of the posterior interosseous nerve e A Complication of rheumatoid arthritis. Arthritis Rheum 1972;15(4):350e2. 9. Muramatsu K, Tanaka H, Taguchi T. Peripheral neuropathies of the forearm and hand in rheumatoid arthritis: diagnosis and options for treatment. Rheumatol Int 2008;28(10):951e7. 10. Gorson KC. Vasculitic neuropathies: an update. Neurologist 2007 Jan;13. 12e9. 11. Said G, Lacroix C. Primary and secondary vasculitic neuropathy. J Neurol 2005;252. 633e41. 12. Sivri A, Guler-Uysal F. The electroneurophysiological evaluation of rheumatoid arthritis patients. Clin Rheumatol 1998;17. 416e9. 13. Lanzillo B, Pappone N, Crisci C, et al. Subclinical peripheral nerve involvement in patients with rheumatoid arthritis. Arthritis Rheum 1998;41. 1196e202. 14. Narayanaswami P, Chapman KM, Yang ML, Rutkove SB. Psoriatic arthritis-associated polyneuropathy: a report of three cases. J Clin Neuromuscul Dis 2007;9(1):248e51.
CASE REPORT
Inflammatory posterior interosseous nerve palsy in a patient with psoriatic arthropathy Erden Ali a,*, Robert Colac ¸o d ¸o b, Patrick Gillespie c, C. Bernard Colac a
Department of Plastic and Reconstructive Surgery, The Lister Hospital, Stevenage, UK University of Bristol School of Medicine, UK c Department of Plastic & Reconstructive Surgery, Addenbrooke’s University Hospital, Cambridge, UK d Rheumatology Unit, Central Middlesex Hospital, Park Royal, London, UK b
Received 9 February 2011; accepted 27 March 2011
KEYWORDS Posterior interosseus nerve; Nerve palsy; Psoriasis; Psoriatic arthropathy; Mononeuritis; Peripheral mononeuropathy
Summary Psoriasis is a chronic, relapsing, inflammatory skin disorder with a strong genetic basis. Five patterns of psoriatic arthritis have been identified: asymmetrical oligoarticular arthritis, symmetrical polyarthritis, distal interphalangeal arthropathy, arthritis mutilans and spondylitis with or without sacroiliitis. Extra-articular disease is uncommon. We report a rare case of an inflammatory posterior interosseus nerve palsy in a patient with known psoriatic arthropathy, where investigation warranted medical treatment over a surgical approach. The commonest cause of posterior interosseus nerve palsy is entrapment at the proximal forearm. Other possible aetiologies include extension of elbow synovitis as described in rheumatoid arthritis, trauma eg. Monteggia fractures, tumours and iatrogenic injuries. We discuss the diagnostic dilemma and the management issues for upper limb surgeons. ª 2011 British Association of Plastic, Reconstructive and Aesthetic Surgeons. Published by Elsevier Ltd. All rights reserved.
Introduction There are several distinctive clinical variants of psoriasis with the plaque type being the most common. Up to 10e20% of patients with plaque psoriasis also experience psoriatic arthritis (PsA).
PsA is an inflammatory seronegative spondyloarthropathy. Joint and skin symptoms occur simultaneously in approximately 15% of people with the disease. In 60% of people the cutaneous manifestations precede the arthritis and in 25%, of those with psoriasis, the arthritis appears first. PsA may mimic rheumatoid arthritis or ankylosing spondylitis.
* Corresponding author. Tel.: þ44 1438 781 535; fax: þ44 1438 284 660. E-mail address: [email protected] (E. Ali). 1748-6815/$ - see front matter ª 2011 British Association of Plastic, Reconstructive and Aesthetic Surgeons. Published by Elsevier Ltd. All rights reserved. doi:10.1016/j.bjps.2011.03.039
e206
E. Ali et al.
A strong genetic predisposition does exist. Approximately eight genetic susceptibility loci (PSORS I-VIII) have been observed.1 The most important locus is considered to be psoriasis susceptibility 1 (PSORS1) locus located on chromosome 6 and can be seen in up to 50% of psoriasis cases.2 Extra-articular disease includes neuropathies, but are less common than in seropositive rheumatoid arthritis. In this case we describe a peripheral mononeuritis of the posterior interosseous nerve (PIN). The PIN is the deep motor branch of the radial nerve and supplies all the extrinsic wrist extensors except extensor carpi radialis longus. Compression or injury to the radial nerve can occur at any point along its course from the brachial plexus. It is thought that compression to the PIN occurs after branches to the wrist extensors and the radial sensory nerve have emerged. Most commonly, this occurs at the supinator muscle at the proximal forearm.3 Clinically, a palsy of the PIN usually presents with weakness or paralysis of the wrist and digital extensors.
Case report We report the case of a 56 year old man who was diagnosed with mild skin psoriasis and psoriatic arthropathy twenty years ago. He had tried several disease modifying antirheumatic drugs and was found to be intolerant of azathioprine, sulfasalazine and methotrexate. He was being maintained on leflunomide 10 mg once daily but was still restricted with neck stiffness and persistent synovitis at metacarpophalangeal joints, proximal interphalangeal joints and both elbows. In April 2008, the patient gradually became unable to extend his right wrist (Figure 1A,B,C). The patient was seen by the plastic surgery department where clinical examination suggested a PIN palsy. Movement at the elbow joint had not changed and the patient did not describe any new or worsening neck symptoms. Exploration was delayed until further investigations were performed in order to ensure that the aetiology was established before potentially unnecessary operative intervention was undertaken. The patient was then referred to the rheumatology department where needle electromyography (EMG) was requested and confirmed the diagnosis. Biceps, triceps, flexor digitorum superficialis (FDS) and extensor carpi radialis longus (ECRL) were used as controls and demonstrated normal motor units and recruitment patterns. Only single motor unit activity was demonstrated in extensor digitorum communis, extensor indicis and extensor carpi ulnaris characterising the lesion as severe. Magnetic resonance imaging (MRI) was then used to exclude any possible nerve entrapment at the cervical spine, elbow or wrist, this combined with the EMG results attributed the aetiology to a vasculitis and not nerve compression. The patient was then managed as having an inflammatory mononeuritis (presumed secondary to microvascular inflammation) of the PIN. In June 2008, infliximab (anti tumour necrosis factor (TNF) therapy) was introduced as a further immunosuppressive therapy to leflunomide. The patient was seen in the out-patient department in August 2008 after having completed three courses of anti-TNF therapy where it was
Figure 1 Images to demonstrate the patient’s inability to fully extend the right wrist. (A) Right lateral view comparing extension of the left and right wrists, (B) lateral/oblique view of the right wrist, (C) oblique view of the right wrist. In all the images, the patient’s psoriatic rash is visible.
revealed he had improved wrist extension and had returned to playing golf. There was a gradual improvement in wrist extension and over a period of approximately eighteen months he had progressed to almost full wrist extension. At present, the patient has 0e5 of extensor lag and has improved significantly with anti-TNF medication and hand
Inflammatory posterior interosseous nerve palsy in a patient with psoriatic arthropathy therapy. Grip strength and TIP-pinch strength are comparable with the contra- lateral side. The patient does not report any functional deficit but did develop an exacerbation of the cutaneous manifestation of the disease post medical treatment with infliximab.4 This subsequently improved with oral steroids.
Discussion After its emergence from the supinator muscle, the PIN may be compressed before it bifurcates into medial and lateral branches. This would lead to a complete paralysis of digital extensors and manifest clinically with dorsoradial deviation of the wrist on attempted extension, secondary to extensor carpi ulnaris paralysis and preservation of ECRL function. If compression occurs after the bifurcation, selective paralysis of muscles occurs. Compression of the medial branch causes paralysis of the extensor carpi ulnaris, extensor digiti quinti, and extensor digitorum communis. Compression of the lateral branch causes paralysis of the abductor pollicis longus, extensor pollicis brevis, extensor pollicis longus, and extensor indicis proprius. The commonest cause of a PIN palsy is compression and this was excluded by MRI. History and electrophysiological studies differentiate between nerve entrapment and a vasculitis. Acute onset of paralysis often associated with neuropathic pain and isolated muscle fasciculations compared with a more progressive history are indicative of a vasculitic lesion or nerve compression respectively.5 With a vasculitis, EMG performed up to 3 weeks from the onset of symptoms shows normal conduction velocities and reduced response amplitudes. EMG performed at a later stage shows fibrillations and polyphasic motor unit potentials due to collateral reinnervation. Conversely, in cases of compression, distal axonal degeneration is difficult to elicit and conduction velocities are slowed.5 The palsy was considered inflammatory in origin and recovery of extensor function occurred during treatment with anti-TNF therapy. It should be noted that etanercept (anti-TNF therapy) has conversely been linked with development of a peripheral mononeuropathy within the context of an inflammatory arthritis.6 Differentials may include a focal myopathy7 or more commonly an extensor tendon rupture, which historically may have warranted radiographic investigations with an injection of Renograffin R8 but now can be excluded with MRI. Rheumatoid arthritis has previously been reported as the cause of PIN palsy due to synovitis of the extensor tendon sheath or from a neuropathy caused by occlusion of the epineural arteries, leading to ischaemic nerve lesions after fibrinoid necrosis and inflammatory infiltration of vessel walls has occurred.8e13 Although there are reports in the literature of inflammatory psoriatic polyneuropathies,14 we believe this is the first report of a psoriatic mononeuritis, not related to compression neuropathy. In the reported case, clinical examination and further investigations excluded compression and medical treatment was instigated. Despite a cutaneous exacerbation of the underlying disease, most likely related to the management of the mononeuropathy, the patient has shown excellent recovery of function.
e207
We report the case of an inflammatory PIN palsy in a patient with known psoriatic arthropathy where the symptoms improved with immunosuppressive therapy. This case highlights that psoriatic arthropathy may be associated with extra-articular disease. When compression of the PIN is diagnosed, surgical exploration and release of the nerve is the commonest treatment for simple mechanical compression. The literature for patients with idiopathic PIN palsy suggests waiting for approximately 6 months before proceeding to exploration. This case highlights the diagnostic dilemma posed to plastic surgeons in a patient who presents with a clinical PIN palsy on a background of inflammatory arthropathy. Differential diagnoses includes extensor dysfunction/rupture which warrants exploration and repair however imaging techniques and investigations such as EMG ensure a diagnosis is established prior to unnecessary surgery.
Conflict of interest statement None.
Acknowledgments The authors would like to thank Professor Jagdeep Nanchahal (Imperial College Health Care) for providing patient data.
References 1. American Academy of Dermatology. Guidelines of care for the management of psoriasis and psoriatic arthritis -Section 1. Overview of psoriasis and guidelines of care for the treatment of psoriasis with biologics; 2008. 2. Scho ¨n MP, Boehncke WH. Psoriasis. NEJM 2005;352:1899e912. 3. Dang AC, Rodner CM. Unusual compression neuropathies of the forearm, part I: radial nerve. J Hand Surg Am 2009;34(10):1906e14. 4. Di Lernia V, Guareschi E. Successful treatment of hand and foot psoriasis with infliximab. Dermatol Online J 2010;16(7):8. 5. Chan JK, Kennett R, Smith G. Posterior interosseous nerve palsy in rheumatoid arthritis: case report and literature review. J Plast Reconstr Aesthet Surg 2009;62(12):e556e60. 6. Hanaoka BY, Libecco J, Rensel M, Hajj-Ali RA. Peripheral mononeuropathy with etanercept use: case report. J Rheumatol 2008;35(1):182. 7. Erdem S, Demerci M, Tan E. Focal myopathy mimicking posterior interosseous nerve syndrome. Muscle Nerve 2001;24:969e72. 8. Chang LW, Gowans JDC, Granger CV, Millender LH. Entrapment neuropathy of the posterior interosseous nerve e A Complication of rheumatoid arthritis. Arthritis Rheum 1972;15(4):350e2. 9. Muramatsu K, Tanaka H, Taguchi T. Peripheral neuropathies of the forearm and hand in rheumatoid arthritis: diagnosis and options for treatment. Rheumatol Int 2008;28(10):951e7. 10. Gorson KC. Vasculitic neuropathies: an update. Neurologist 2007 Jan;13. 12e9. 11. Said G, Lacroix C. Primary and secondary vasculitic neuropathy. J Neurol 2005;252. 633e41. 12. Sivri A, Guler-Uysal F. The electroneurophysiological evaluation of rheumatoid arthritis patients. Clin Rheumatol 1998;17. 416e9. 13. Lanzillo B, Pappone N, Crisci C, et al. Subclinical peripheral nerve involvement in patients with rheumatoid arthritis. Arthritis Rheum 1998;41. 1196e202. 14. Narayanaswami P, Chapman KM, Yang ML, Rutkove SB. Psoriatic arthritis-associated polyneuropathy: a report of three cases. J Clin Neuromuscul Dis 2007;9(1):248e51.