Eosinophilia-Myalgia Syndrome

1. See Also
   1. Fibromyalgia
2. Associated Conditions
   1. Hypothyroidism
3. Pathophysiology
   1. Linked to L-Tryptophan usage
4. Symptoms
   1. Myalgias (Uniformly present)
      1. Rapid onset with persistent pain
      2. Severe and incapacitating pain
      3. Associated with muscle spasms (esp. calves, Abdomen)
      4. Associated with perceived weakness
      5. Exacerbated by movement
   2. Arthralgias (73%)
   3. Pruritus
   4. Non-productive cough with Dyspnea (59%)
   5. Neuropathy (27%)
      1. Paresthesia or Hypesthesia (e.g. Burning sensation)
5. Signs
   1. Rash (60%)
   2. Peripheral Edema (59%)
      1. Cutaneous non-Pitting Edema
   3. Periorbital edema (28%)
   4. Fever (36%)
   5. Alopecia (28%)
   6. Hepatomegaly (5%)
   7. Thickened skin (32%)
6. Labs
   1. Complete Blood Count (CBC)
      1. Elevated Peripheral Eosinophil Count
      2. Leukocytosis (85%)
   2. Aldolase increase (46%)
   3. Creatine Kinase increase (10%)
   4. Erythrocyte Sedimentation Rate (ESR) increased (33%)
   5. Liver Function Test (LFT) abnormality (43%)
   6. Antinuclear Antibody (ANA) frequently positive
      1. Speckled pattern most common
7. Radiology: Chest XRay findings
   1. Infiltrates (17%)
   2. Pleural Effusions (12%)
8. Differential Diagnosis
   1. Polymyositis
   2. Polymyalgia Rheumatica
   3. Trichinosis
   4. Polyarteritis Nodosa
   5. Churg Strauss
   6. Systemic Sclerosis
   7. Hypereosinophilic syndrome
9. Diagnosis: Criteria from CDC Cases
   1. Peripheral Eosinophil Count >1000 cells/mm
   2. Severe myalgias that interfere with daily activity
   3. Exclude other diagnoses
      1. Infection
      2. Neoplastic Disease
      3. Other diagnosis responsible
10. Management
    1. General Therapies
       1. Systemic Corticosteroids
          1. Not uniformly effective
          2. Unlikely effective if no response by 4-6 weeks
          3. Predictors of response
             1. Edema
             2. Eosinophilia
          4. High doses are required initially
       2. Other experimental therapies
          1. Methotrexate
          2. Vitamin B6
          3. Cyclosporine
          4. Cyclophosphamide
          5. Plasmapheresis
    2. Myalgias and Muscle spasms (very difficult to treat)
       1. Quinine sulfate
       2. Tricyclic Antidepressants
       3. Methocarbamol
       4. Cyclobenzaprine
       5. Dantrolene
       6. Baclofen
       7. Benzodiazepines
       8. Narcotics Analgesics may be needed
       9. Chronic Pain Management
11. Reference
    1. Freundlich (1993), 1150-7
    2. Hertzman (1995) J Rheumatol 22(1):161-3 [PubMed]
    3. Swygart (1990) JAMA 264:1698-1703 [PubMed]