Hypothyroid Myopathy Differential Diagnoses

Updated: Apr 07, 2015
  • Author: Divakara Kedlaya, MBBS; Chief Editor: Stephen Kishner, MD, MHA  more...
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Diagnostic Considerations

Myasthenia gravis

Myasthenia gravis has been associated with Graves disease and hypothyroidism. [27] Patients present with proximal muscle weakness that may be fatigable. Eventually, they can have dysphagia and respiratory distress.

Other metabolic, mitochondrial, and inflammatory myopathies

Glycogen metabolism deficiencies: These conditions are divided into dynamic and static deficiencies.

Dynamic myopathies: Manifestations of these disorders include exercise intolerance, pain, muscle cramps, and myoglobinuria.

  • Type V - Phosphorylase (McArdle disease)
  • Type VII - Phosphofructokinase (Tarui disease)
  • Type VIII - Phosphorylase B kinase
  • Type IX - Phosphoglycerate kinase
  • Type X - Phosphoglycerate mutase
  • Type XI - Lactate dehydrogenas

Static deficiencies: These disorders are associated with fixed weakness, but not with exercise intolerance or myoglobinuria.

  • Type II - Alpha-1,4 glucosidase (acid maltase)
  • Type III - Debranching
  • Type IV - Branching

Lipid metabolism deficiencies: These disorders can be accompanied by the following dynamic or static manifestations:

  • Carnitine palmitoyl transferase
  • Primary systemic/muscle carnitine deficiency
  • Secondary carnitine deficiency (eg, beta-oxidation defects, medications [such as valproic acid])
  • Purine metabolism deficiencies (eg, myoadenylate deaminase deficiency)

Mitochondrial myopathies

  • Pyruvate dehydrogenase complex deficiencies (eg, Leigh syndrome)
  • Progressive external ophthalmoplegia
  • Kearns-Sayre syndrome
  • Mitochondrial encephalopathy with lactic acidosis and strokelike episodes
  • Myoclonic epilepsy and ragged red fibers
  • Mitochondrial neurogastrointestinal encephalomyopathy
  • Mitochondrial depletion syndrome
  • Leigh syndrome and neuropathy, ataxia, or retinitis pigmentosa
  • Succinate dehydrogenase deficiency

Channelopathies are also differential diagnoses for myopathy.

Inflammatory myopathies are important differentials as well and may be difficult to differentiate from pure endocrine causes, including a heterogenous group of acquired, nonhereditary disorders characterized by muscle weakness and inflammation indicated by muscle biopsy.

Idiopathic inflammatory myopathies

  • Polymyositis
  • Dermatomyositis
  • Inclusion body myositis
  • Overlap syndromes with other connective tissue disease
  • Sarcoidosis and other granulomatous myositis conditions
  • Beh ç et syndrome
  • Inflammatory myopathies and eosinophilia
  • Focal myositis
  • Myositis ossificans

Bacterial infections

  • Staphylococcus aureus
  • Escherichia coli
  • Yersinia species
  • Legionella
  • Gas gangrene ( Clostridium welchii)
  • Leprous myositis
  • Lyme disease

Viral infections

  • Acute influenza or other viral infections
  • Retrovirus-related myopathies (human immunodeficiency virus [HIV], human T-cell leukemia virus type 1)
  • Hepatitis B and C
  • Postpolio syndrome

Parasitic infections

  • Trichinosis
  • Toxoplasmosis
  • Cysticercosis

Fungal infections

  • Candida species
  • Cryptococcus species
  • Sporotrichosis species

Differential Diagnoses