PMR/GCA/polymyositis/dermatomyositis Flashcards
Polymyalgia Rheumatica (PMR)
general
Etiology
Most common chronic inflammatory condition in older adults
Primarily affects proximal muscles and joints, causing disability
Closely associated with giant cell arteritis
Many consider the two disorders to be aspects of the same process
May occur independently or concomitantly
Polymyalgia rheumatica is more common than giant cell arteritis
Commonly affects:
Patients > 50 years of age
♀>♂
Incidence:
↑ with age
Peak incidence – 70-80 years
More likely to develop in patient with HLA-DR4 and after adenovirus or parvovirus B-19 infection
First described in 1888 and referred to as “senile rheumatic gout”
This not a myopathy
Polymyalgia rheumatica
Hallmark S/Sx’s
Hallmark symptoms:
Proximal muscle and joint pain
Most severe in the neck, shoulders, upper back, and buttocks
Develops over weeks to months
Synovitis, bursitis, tenosynovitis
Proximal muscle stiffness
Typically in the morning lasting > 60 minutes
After prolonged sitting or reclining
Muscle tenderness
Shoulder involvement in 95% of cases
Synovitis: synovium of a joint becomes inflamed(swollen)
Bursitis: painful swelling of a small, fluid-filled sac called a bursa; bursa cushion the bones, tendons, and muscles near joints
Tenosynovitis: broad term describing the inflammation of the fluid-filled synovium within the tendon sheath
Polymyalgia rheumatica
Systemic symptoms
Fever
Night sweats
Fatigue
Anorexia
Weight loss
No weakness
Weakness may develop later (disuse atrophy)
Patients with complain of trouble with getting out of bed or performing daily activities
Often will have to “roll out of bed”
Polymyalgia rheumatica
Dx
No definitive test for polymyalgia rheumatica
Other possible causes for symptoms must be ruled out (diagnosis of exclusion)
Labs:
Inflammatory Markers:
ESR
Normal ESR for a patient’s age is best calculated as age/2 for men, and age+10/2 for women
Mean ESR is 65 mm per hour
>100 mm per hour raises concern for concomitant giant cell arteritis or underlying malignancy
CRP- not dependant on age
Often elevated when ESR is normal
More sensitive than ESR
Less affected by age
CK should be normal- there is not muscle destruction (not a myopathy)
Electromyography (EMG)…should this test be normal
Polymyalgia rheumatica
Normal ESR for a patient’s age is best calculated as
age/2 for men, and age+10/2 for women
Mean ESR is 65 mm per hour
Polymyalgia rheumatica
Tx
Corticosteroids
Prednisone 15-20 mg PO once daily
Dramatic improvement within hours to a day (supports the diagnosis)
If giant cell arteritis is also present, prednisone dosing will need to be higher
Taper prednisone to the lowest clinically effective dose as symptoms subside
Mean length of treatment is 1.8 years
Monitor for steroid complications (diabetes, hypertension, osteoporosis)
Methotrexate 10-15 mg PO once weekly
Used in patients who have frequent recurrences
Folic acid 1 mg daily
Use of bisphosphonates, specifically alendronate (Fosamax) and risedronate (Actonel), can increase bone mineral density and decrease vertebral fractures in patients on long-term glucocorticoid therapy
polymyalhia rheumatica
Giant Cell Arteritis
General
Also known as temporal arteritis
Most common type of vasculitis in adults
Affects medium and large arteries with a predilection for the extracranial carotid branches
More serious condition than polymyalgia rheumatica
Common affects:
♀>♂
Incidence:
↑ with age
Peak incidence - 70-80 years
GCA
Patho
Caused by the deposition of immune complexes in the involved arteries (those containing elastic tissue), resulting in a local immune response
Eliciting cause of this immune system reaction is not known
? Initiating viral pathogen
Intimal hyperplasia and luminal obstruction leads to ischemic manifestations
May be localized, multifocal, or widespread
GCA
S/Sx
Headache (85%)
Most common initial and frequent symptom
Involves the temporal and occipital region(s)
Burning or boring-type pain
Tenderness of arteries (temporal artery)
Swollen, nodular and/or erythematous
Jaw claudication
Weakness in the muscles of mastication (inflammation of the maxillary artery)
Onset with chewing and relieved by rest
Visual symptoms
Diplopia, blurring, or amaurosis fugax → blindness
Loss of vision occurs within hours to days
Contralateral eye is often affected within one to two weeks
Jaw claudication and visual symptoms are ischemic warning signs
Amaurosis fugax: painless temporary loss of vision in one or both eyes
GCA
Systemic symptoms:
Fever
Fatigue
Anorexia
Weight loss
GCA
Suspicion of Dx
Suspicion based on history and physical examination
Suspected in patients> 50 if any of the following develops, especially if they also have symptoms of systemic inflammation:
A new type of headache
Any new symptom or sign compatible with ischemia of an artery above the neck
Jaw muscle pain during chewing
Temporal artery tenderness
Unexplained subacute fever
GCA
Dx
Inflammatory markers
ESR
A normal ESR does not exclude giant cell arteritis
CRP
Temporal artery biopsy
Obtained within one week of starting treatment
Performed on the patient’s most symptomatic side
Sample of 1-2 cm; up to 5 cm, increase the yield
Negative biopsy does not rule out disease as temporal arteritis does not affect arteries in a continuous fashion; if suspicion remains high, obtain a color-duplex US of the temporal artery or an MRI with contrast of the cranial vessels
GCA
Tx
Medical emergency due to neuro-ophthalmic complications
Referral to rheumatology
Corticosteroids
Uncomplicated disease
Prednisone 40-60 mg daily
Complicated disease (visual disturbances)
methylprednisolone (Solu-Medrol) 500-1,000 mg IV daily for 3-5 days, then Prednisone 60 mg PO daily
If symptoms lessen,prednisone can be tapered gradually
Most patients require at least 2 years of treatment with corticosteroids
Prevention of long-term corticosteroid adverse events
PPI for gastrointestinal protection
Antiresorptive drug (bisphosphonate) to increase bone mass and prevent osteoporosis
To reduce exposure to corticosteroids (adjunctive agent)
Methotrexate
Tocilizumab – interleukin-6 inhibitor
Low-dose aspirin
Decrease cerebrovascular complications
81 mg PO daily
If there is symptomatic relapse with tapering of steroids, immediately increase the steroid dose and start tocilizumab or a DMARD until symptoms resolve; these patients will need a longer steroid taper
GCA
Polymyositis (PM)
General
Autoimmune inflammatory myopathy caused by T cell-mediated (CD8 T cells) muscle injury
Tends to present between 30-60 years; smaller peak around age 15
♀>♂
Etiology is unknown - Idiopathic
Possible genetic predisposition
HLA-A1, HLA-B8, HLA-DR3
Environmental factors
Infections: HIV, Hepatitis B & C
Drug-induced: ACE inhibitors, D-penicillamine, Hydralazine
Associated medical conditions
Malignancy
Connective-tissue disorders
Polymyositis
Muscle weakness:
Develops gradually over weeks to months
Symmetric, involving proximal muscles
Particularly evident when:
Climbing stairs
Brushing hair
Rising from a seated position
Reaching for overhead objects
Holding up the head
Pharyngeal weakness causing dysphagia
Associated myalgias occur in a small percentage of patients
Complaints of aches or cramps
Distal muscle involvemnt and facial muscle involvement can with advanced
small amount of pain. WEAKNESS.
Polymyositis – weakness, normally without pain; muscle destruction
Polymyalgia rheumatica – painful muscles, without weakness; no muscle destruction
Polymyositis
Other S/Sx
Arthralgias or arthritis:
Symmetric
Joints commonly involved:
Knees
Wrists
Hands
Raynaud’s phenomenon may be present
Constitutional symptoms:
Weight loss
Fatigue
Low-grade fever
Polymyositis
Labs and Dx
Labs:
CBC
Leukocytosis
Thrombocytosis
Inflammatory markers
↑ Erythrocyte sedimentation rate (ESR)
↑ CRP
ANA positivity
Nonspecific and not diagnostic
Seen in ⅓ of patients
Muscle enzymes
↑↑ CK – 50x normal; level is a good indicator of disease activity
Myositis-specific antibody testing:
Anti-signal recognition protein (anti-SRP) antibodies
Anti-Jo-1 antibodies
Electromyography (EMG):
Helps to support the diagnosis
Muscle biopsy:
Confirms the diagnosis
know your antibodies
Polymyositis
Tx
High-dose systemic glucocorticoids (1st-line)
50% of patients with PM will not respond to steroids alone
Therapy is usually needed for 9–12 months
Slowly tapered off
Levels of muscle enzymes are monitored to determine response to therapy
Immunosuppressive therapy
Methotrexate, azathioprine
Used in conjunction with glucocorticoid therapy
IV immunoglobulin (IVIG)
Patients with severe life-threatening weakness (severe dysphagia, respiratory insufficiency)
Polymyositis - complications
Malignancy
Usually detected within the 1st year of diagnosis
Observed in men > 60 years of age with severe systemic involvement
Common cancers: non-Hodgkin’s lymphoma, and bladder, lung, breast, ovarian, stomach, pancreatic, prostate, and colorectal cancer
Patients diagnosed with PM should be evaluated for possible underlying malignancy
Polymyositis
Respiratory complications:
Interstitial lung disease → pulmonary hypertension and cor pulmonale
Aspiration pneumonia due to dysphagia
Polymyositis
Adverse effects of medical therapy:
Corticosteroid therapy
Osteoporosis and compression fractures
Insulin resistance → diabetes mellitus
Hypertension
Immunosuppression therapy
Opportunistic infections
Upper respiratory tract infections and pneumonia
Skin infections
Dermatomyositis (DM)
general
Typical sx
An autoimmune inflammatory myopathy resulting from immune-complex deposition in the muscle capillaries
Patients present with symptoms similar to those observed in PM
Also exhibit characteristic cutaneous manifestations (heliotrope rash, Gottron’s sign, Gottron’s papules)
Diagnosis is based on clinical presentation and antibody evaluation, and may be confirmed with biopsy
Management includes systemic glucocorticoids, immunosuppressants, and screening for malignancy
Dermatomyositis
Cutaneous Manifestations
Heliotrope rash:
Pathognomonic feature
Erythematous/violaceous rash around the upper eyelids
Periorbital edema
Gottron’s papules:
Pathognomonic feature
Symmetric
Erythematous/violaceous papules
Located on the dorsal metacarpophalangeal and interphalangeal joints
Facial erythema:
“Butterfly” pattern that mimics the malar rash of lupus
Involves the nasolabial folds
Gottron’s sign:
Erythematous/violaceous macules or patches
Often on extensor surfaces (hands, elbows, knees, and ankles)
Nail changes:
Dilated capillary loops at the proximal nailfold
Periungal erythema
Cuticle hypertrophy
Calcinosis cutis (common in children)
Deposition of calcium within the skin
Polymyositis VS polymyalgia rheumatica
Polymyositis – weakness, normally without pain; muscle destruction
Polymyalgia rheumatica – painful muscles, without weakness; no muscle destruction
