Inclusion Body Myositis

1. Inclusion Body Myositis Gabrielle Wierzbicki Ithaca College Clinical Education I Summer 2010

2. Inclusion Body Myositis • Sporadic inclusion body myositis (IBM) is an acquired inflammatory muscle disease • IBM is considered the most frequent muscle disease affecting individuals over 50 years old • Clinical hallmark of IBM is early weakness and atrophy of the quads, DF, & wrist and finger flexors • The weakness may affect any muscle group, is frequently asymmetrical, and can cause dysphagia

3. Signs & Symptoms • Muscle weakness is gradual, usually over months or years • Proximal and distal muscles are both effected • Falls and tripping are usually the first noticeable signs of IBM • Atrophy of the finger flexors may also cause difficulty with pinching, buttoning, and gripping objects

4. Signs & Syptoms Quadriceps atrophy muscle wasting

5. Etiology • Proteins are assembled in the ER of a cell, and requires the correct sequence of AA to properly assemble proteins. Incorrect sequences create protein misfolding, and an accumulation can cause an inflammatory response • The misfolded proteins activate ERAD (ER activated degradation) and UPR (unfolded protein response) to try to bring the cells back to homeostasis. • There is an abnormal accumulation of the amyloid-β precursor protein and its proteolytic fragment, amyloid-β (Aβ) in vacuoles, called “inclusion bodies”

6. Inclusion Bodies • Granular material found in the vacuoles in muscle fibers • Found to have abnormal amounts of amyloid proteins • Same protein found in Alzheimer’s Disease patients

7. Although IBM is characterized by inflammation, it does not respond well to immunosuppresive therapy • This observation may suggest that IBM is more of a degenerative disease than an autoimmune inflammation myopathy. Inflmmation may be a secondary response, not the primary cause of the disease

8. Treatment • Most patients are not responsive to treatment with anti-inflammatory, immunosuppressive, or immunomodulatory drugs • There are currently no available medications to treat the disease’s progression

9. Therapy Treatment • Exercise training was previously avoided because it was thought to increase the inflammatory response in the effected muscles • New studies have shown the safety of aerobic and resistance training, even at high intensities • Studies have shown that exercise stabilizes and improves muscle performance without increasing the markers for the disease • Physical exercise can result in beneficial results & improvement of QOL • Other modalities may be used for strength gains, such as NMES, vascular occlusion, or whole body vibration

10. Spector et al. • Training program: 3 sets of 10-20 reps 3 times a week x 12 weeks • Knee ext, knee flex, elbow flex, wrist flex • Strength gains ranged from 25%-120% • Most strength gains in the least weakened muscles • No significant changes in fatigue levels or ability to perform daily activities were shown in this study

11. Ulnar Nerve Pathology

12. Brachial Plexus Ulnar nerve: Terminal branch of medial cord, receiving fibers from C7 (some), C8, T1.

13. Anatomical Path • Descends medial arm, passes post. to med. epicondyle of humerus • Enters the forearm by passing between the 2 heads of the FCU and descends the ulnar aspect of forearm. Enters palmar side of hand by passing through Guyon’s canal (ulnar canal) at the wrist

14. Anatomical Path • Palmar cutaneous nerve (sensory for base of medial palm) branches before entering the ulnar canal • On entering the hand, the ulnar nerve is attached to fascia on the anterior surface of the flexor retinaculum as it passes between the pisiform and ulnar artery • Once through the canal, branches into superficial and deep nerves • Superficial branch: motor for palmaris brevis and sensation of digital dorsal aspects of digits IV and V, ulnar side of digit IV, & proximal palm • Deep branch: motor for hypothenar mm, lumbricals (IV & V), interossei, adductor pollicis, deep head of FPB

15. Muscle Innervation • Flexor carpi ulnaris • Ulnar half of flexor digitorum profundus • Intrinsic mm of the hand • Deep head of flexor pollicis brevis • Adductor pollicis (oblique and transverse heads) • Abductor digiti minimi • Flexor digiti minimi brevis • Opponens digiti • 3rd and 4th lumbrical • 1-4 dorsal interossei • 1-3 palmar interossei

16. Sensory Innervation • Palmar aspect of digit V and medial half of digit IV • Fingertips of digits IV and V

17. Ulnar Nerve • The ulnar nerve is referred to as “the nerve of fine movements” • >27% of nerve lesions in UE involve the ulnar n. • Ulnar nerve injuries usually occur: • posterior to medial epicondyle (fx of med. epicondyle) • cubital tunnel (compression between the heads of the FCU) • at the wrist (compression in ulnar canal) • in the hand

18. Cubital Tunnel

19. Cubital Tunnel Syndrome • Compression between the humeral and ulnar heads of the FCU • The nerve is very superficial when it passes posterior to the medial epicondyle, and then dives between the humeral and ulnar heads of the FCU • Entrapment at this location effects the entire innervation of the ulnar n, both sensory and motor functions

20. Guyon’s Canal • Space between the pisiform and hamate bones in the wrist where the ulnar nerve and ulnar artery run into the hand

21. Guyon’s Canal Stenosis • Effects motor level innervation of ulnar n. after passing through Guyon’s canal • Effects the intrinsic hand mm. innervated by the ulnar n. • Does not effect the innervation of the FDP or FCU • Back of hand has normal sensation

23. Nerve Entrapment • Compression at the cubital tunnel will completely impair all function of the ulnar n. (sensory & motor) • Compression at theulnar canal will not effect motor function innervated before the wrist, but will effect sensory distribution of the medial 2 fingers and motor function of the intrinsic mm of the hand

24. What does this mean? • Weakness in wrist flexion accompanied by radial deviation • Weakness in flexion at PIP and DIP jts in digits IV and V • Weak MCP flexion ------------------------------------------------------------------------ • Atrophy of hypothenar eminence • Weakness in pinky flexion, inability to oppose and abduct • Inability to adduct MCP jt of thumb • Inability to abduct and adduct fingers II-V • Numbness/tingling in palm of hand and digits IV and V

25. Claw hand deformity • Inability to extend the IP joints when extending the fingers • Unopposed action of the extensors and FDP because lumbricals of digits IV and V are paralyzed • Lumbricals flex the MCP and extend the IP jts of the digits • Seen especially when patient is asked to extend the fingers • Seen more with Guyon canal stenosis- clawing is more severe

26. Ulnar paradox • Not severe claw hand deformity, but inability to flex DIP and weakness of flexing MCP & PIP of digits IV and V • Seen with higher nerve injuries (cubital tunnel syndrome) • More severe muscle impairment • FDP and lumbricals for digits IV and V are impaired, there is unopposed action of the ED

27. Diagnostic Tests • Froment’s Sign • Tests the integrity of the adductor pollicis muscle (both heads) for ulnar nerve pathology • Last muscle innervated by the deep branch of the ulnar nerve • + sign: flexion at the IP joint of the thumb

28. Diagnostic Tests • Tinel’s Sign at the elbow: • Tests the integrity of the ulnar nerve for compression • Tap the ulnar n. in the groove between the olecranon process & medial epicondyle • + sign: tingling sensation in ulnar distribution of forearm & hand distal to the point of compression

29. Diagnostic Tests • Electrodiagnostic studies can be helpful in determining the severity of the entrapment and finding the exact site of the compression • Electromyography (EMG) and nerve conduction velocity (NCV) examinations can define the type of pathology

30. Therapy Treatment • Reduction of overload, pain, & inflammation • Rest is essential for n. injuries- ↓ inflammation around nerve • Splinting can also be helpful in relieving symptoms • Resting (severe cases 40-60°) or night splinting to put nerve in least stressed position and prevent elbow flex while sleeping (30-45° flexion) • Reduce external pressure on elbow • Elbow pads, examining work area • Pain reducing modalities • Cryotherapy, ultrasound (non-thermal at low intensity), pulsed signal therapy • PROM exercises

31. Therapy Treatment • Strength and normal arthrokinematics • Gradual progression from splint to normal activities and sub-maximal exercise • Goal is for pain-free elbow, forearm, wrist, and finger motion • Gentle ROM (not end-range) and flexibility of arm & shoulder • Joint mobilization (distraction/post glide) if there is ↓ ROM for elbow extension • Also medial/lateral glides for overall jt play & end-range extension • Submax strengthening at very low resistance & high repetitions- promotes muscular endurance & blood flow • Progress to higher resistance, higher repetitions, closed chain exercises, plyometrics • Rotator cuff and UE strengthening to prevent imbalances and maintain strength & ROM

32. Therapy Treatment • Gradual return to activity • Pain free ROM & adequate arm & grip strength required before returning to normal activity • Manual soft tissue techniques, such as active-release, nerve gliding, & scar-tissue mobilization can be used to release scar tissue adhesions on muscle, fascia, and nerves

33. Therapy Treatment • Maintenance • Continued increase in strength, power, and endurance • Continue to return to activity, while also stretching and strengthening • Lasts from 90 days to 1 year after injury • If symptoms persist (pain limiting function, nerve instability, neurological symptoms), the patient is most likely a candidate for surgical intervention

34. Surgical Treatment • Surgery to release the entrapment of the nerve for more severe cases • Decompression- release of ulnar nerve at medial epicondyle by cutting the fascia and aponeurosis • Anterior transposition- placement of the ulnar nerve in front of the elbow • Subcutaneous transposition- releasing the nerve from all potential sites of entrapment as well as placing the nerve in front of the elbow • Submuscular transposition- releasing the nerve from all potential sites of entrapment, & placing of the ulnar nerve in front of the elbow beneath the pronator teres muscle • Intramuscular transposition- ulnar nerve is placed in a muscular tunnel in the pronator teres m. anterior to the elbow • Medial epicondylectomy- medial epicondyle removed and n. placed anterior to the remaining bone

35. References • Ahmed M. Heat Shock Protein Induction as a Therapeutic Strategy for Inclusion Body Myositis. Neuromuscular Disorders: Poster Presentations. 2010: S5-S30. • Askanas V, Engel W.K. Accumulation of amyloid-β (Aβ) and misfolded proteins in muscle fibers suggest that inclusion-body myositis (s-IBM) is a myodegenerative and conformational disorder. Invited Speakers Abstracts. 2005: S25. • Dahlbom K, Lindberg C, Oldfors A. Inclusion Body Myositis: Morphological Clues to Correct Diagnosis. Neuromuscular Disorders. 2002;12: 853-857. • De Salles Painelli V, Gualano B, Artioli G, et al. The Possible Role of Physical Exercise on the Treatment of Idiopathic Inflammatory Myopathies. Autoimmunity Reviews. 2009; 8: 355-359.

36. References • Eriksson M, Lindberg C. Hand Function in Inclusion Body Myositis. Inclusion Body Myositis II and Distal Myopathies: Poster Presentations. 2006: 644-726. • Grey’s Anatomy • Heikkilä S, Viitanen J, Kautiainen H, et al. Rehabilitation in Myositis: Preliminary Study. Physiotherapy. 2001: 87; 301-309. Hereditary • Moore K, Dalley A, Agur A. Clinically Oriented Anatomy. 6th edition. Philadelphia, PA: 2010. • Robertson C, Saratsiotis J. A Review of Compressive Ulnar Neuropathy at the Elbow. Journal of Manipulative and Physiological Therapeutics. 2005; 28: