Case:04 Weakness

85 year old man with an insidious onset of weakness, noticed in the last few months.

While he was away in Canada he noticed that he didn't have the strength to go up the stairs. Before the he also noticed that he had weakness in his hands. He has noticed that his weakness is progressing. He has ongoing difficulty climbing stairs, needing to hold onto the handrail but going down the stairs is OK. He needs to use his arms to get out of chairs. He can still walk on the flat, and has been walking 4km every day for 10 years - still able to do that. He struggles to lift things. His legs feel clumsy with putting on socks and trousers. He has difficulty opening jars and can't press aerosol sprays.

Overall the lower limb symptoms are more pronounced than the upper limb symptoms. He has had three falls in the last three months. He has had to call the ambulance each time because he hasn't been able to get up on his own. He hasn't had any difficulty in swallowing or breathing, no double vision, no eyelid drooping.

He gets frequent cramps in his hands and legs but overall the weakness is his main complaint, not pain.

He also noticed that his feet have been numb in the last year or so. It started with his toes but has moved more proximally.

PMHx

Vasomotor rhinitis
Psoriasis
Osteoarthritis
History of obesity, now overweight
Gout
Left ventricular hypertrophy
Atrial fibrillation
Hypertension
Bilateral hip joint replacements
Cataract surgery

Medications

Atorvastatin 40mg
Metoprolol 47.5mg
Spironolactone 25mg
Candesartan 8mg
Aspirin 100mg

Social history

Lives in a retirement village
Wife has Alzheimers, she has recently gone into care in a dementia unit

No fasciculations
Marked atrophy proximal lower limbs, quadriceps worse than hamstrings, thighs 38cm bilaterally. Below knee musculature possible mild wasting left tibialis anterior only.
Possible atrophy bilateral forearm flexors, right worse than left.
Lower limb strength: Proximal lower limb weakness with hip flexion 4-/5, hip extension 4+/5, knee flexion 4/5, knee extension 4/5. Distal myotomes normal.
Upper limb strength: Mild weakness right extension 4-/5. Keygrip mild weakness, finger flexors moderate weakness, 5th finger abduction mild weakness, wrist extension normal. Left distal weakness worse than right. Proximal upper limb strength normal.
Reduced pinprick sensation soles of feet only
Vibration sense absent wrists, knees, ankles toes.
Cranial nerve examination normal.

CK 360 and 432 (sequential days)
Myositis antibody panel negative (including HMG-CoA reductase and cN-1A)
ANA negative
CRP and ESR normal
HbA1c 43
B12 normal 305

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MRI bilateral femur report

bilateral hip replacements causes substantial metallic artefact obscuring the hip joints, supperior adductor muscles, and small external rotators.
Bilateral trochanteric bursal effusions
Prominent T2 high signal bilatearl vastus lateralis, gracilis, anterior adductor magnus, biceps femoris.
T1 fatty atrophy primarily of vastus lateralis
No bone oedema
Findings consistent with acute muscle inflammation involving both the quadriceps and adductor compartments. Findings are consistent with an inflammatory myopathy however MRI is non specific for the cause of myositis. MRI can guide biopsy if clinically appropriate.

Symptoms and signs are consistent with a diagnosis of inclusion body myositis with the proximal lower limb and distal upper limb pattern of painless progressive weakness in an elderly man. The CN-1A antibodies are positive in only 60% of IBM cases. There is no treatment or cure for IBM. The best management is regular exercise and physiotherapy.

He also has a separate age related length dependent peripheral neuropathy.