eMedicine Specialties > Physical Medicine and Rehabilitation > Muscular Dystrophy

Becker Muscular Dystrophy: Differential Diagnoses & Workup

Author: Benjamin R Mandac, MD, Chief of Physical Medicine and Rehabilitation, Medical Director of Pediatric Rehabilitation, Kaiser Permanente at Santa Clara
Contributor Information and Disclosures

Updated: Apr 18, 2008

Differential Diagnoses

Congenital Muscular Dystrophy
Congenital Myopathies
Emery-Dreifuss Muscular Dystrophy
Facioscapulohumeral Dystrophy
Kugelberg Welander Spinal Muscular Atrophy
Limb-Girdle Muscular Dystrophy

Other Problems to Be Considered

Duchenne muscular dystrophy
Distal muscular dystrophy
Scapulohumeral dystrophy
Spinal muscular atrophy
Toxic or metabolic disorders
Spinal cord tumors
Inflammatory myopathy

Workup

Laboratory Studies

  • After a thorough history has been taken and a physical examination has been performed, a diagnosis of BMD may be confirmed with the following lab study sequence:
    • Serum creatine kinase shows moderate-to-severe elevation (that is, 5-100 times the normal level).
    • Dystrophin gene deletion analysis shows specific exon deletions in about 98% of cases. Test methods include the multiplex polymerase chain reaction, southern blot analysis, and fluorescent in situ hybridization.
    • Muscle biopsy with dystrophin antibody staining demonstrates the presence of dystrophin in variable percentages. This may be helpful in the young child with no maternal history.
    • Laboratory evaluation is generally confirmatory if the patient possesses a phenotype that is consistent with muscular dystrophy and has a family history of BMD. Laboratory and phenotypic expression confirm sporadic cases. A clinical picture of muscular dystrophy, coupled with a preserved ambulatory status beyond age 16 years, is consistent with a diagnosis of BMD.
  • Other laboratory studies that may be indicated include the following:
    • Liver function screen for aspartate transaminase and alanine transaminase
    • Muscle biopsy
    • Standard histology

Imaging Studies

  • Spinal radiographs may be performed to follow the progression of scoliosis, particularly during adolescence.

Other Tests

  • Electromyography may be indicated.
    • Expect normal nerve conduction with possible borderline-to-low motor evoked responses.
    • Expect increased insertional activity with myopathic motor unit action potentials (ie, short duration, low-to-normal amplitude, rapid recruitment, decreased units).
    • An electrodiagnostic study will facilitate a distinction between a muscular and a primary nerve process (eg, anterior horn cell disease, hereditary polyneuropathies).
    • Electromyography also may assist in identifying which muscle groups would be optimal for biopsy.
  • An electrocardiogram/echocardiogram may show cardiomyopathy and/or arrhythmia. Dilated cardiomyopathy manifests after age 20 years; the risk progressively increases with age.
  • Pulmonary function testing may reveal bellows failure caused by progressive weakness.
  • Associated restrictive disease may be seen with scoliosis or a poorly compliant chest.

Histologic Findings

Standard muscle biopsy alone does not support a diagnosis of BMD. Histologic changes — specifically, findings of degenerating muscle fibers, a variation in fiber size, focal necrosis, regeneration, and a proliferation of connective tissue, as well as fatty replacement of degenerated muscles — point to a muscular dystrophy.

More on Becker Muscular Dystrophy

Overview: Becker Muscular Dystrophy
Differential Diagnoses & Workup: Becker Muscular Dystrophy
Treatment & Medication: Becker Muscular Dystrophy
Follow-up: Becker Muscular Dystrophy
References
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References

  1. Becker PE, Kiener F. [A new x-chromosomal muscular dystrophy.]. Arch Psychiatr Nervenkr Z Gesamte Neurol Psychiatr. 1955;193(4):427-48. [Medline].

  2. Becker PE. Two families of benign sex-linked recessive muscular dystrophy. Rev Can Biol. Sep-Dec 1962;21:551-66. [Medline].

  3. Angelini C, Fanin M, Pegoraro E, et al. Clinical-molecular correlation in 104 mild X-linked muscular dystrophy patients: characterization of sub-clinical phenotypes. Neuromuscul Disord. Jul 1994;4(4):349-58. [Medline].

  4. Gurvich OL, Tuohy TM, Howard MT, et al. DMD pseudoexon mutations: splicing efficiency, phenotype, and potential therapy. Ann Neurol. Jan 2008;63(1):81-9. [Medline].

  5. Ashton EJ, Yau SC, Deans ZC, et al. Simultaneous mutation scanning for gross deletions, duplications and point mutations in the DMD gene. Eur J Hum Genet. Jan 2008;16(1):53-61. [Medline].

  6. Arahata K, Beggs AH, Honda H, et al. Preservation of the C-terminus of dystrophin molecule in the skeletal muscle from Becker muscular dystrophy. J Neurol Sci. Feb 1991;101(2):148-56. [Medline].

  7. Koenig M, Beggs AH, Moyer M, et al. The molecular basis for Duchenne versus Becker muscular dystrophy: correlation of severity with type of deletion. Am J Hum Genet. Oct 1989;45(4):498-506. [Medline]. [Full Text].

  8. Schwartz M, Hertz JM, Sveen ML, et al. LGMD2I presenting with a characteristic Duchenne or Becker muscular dystrophy phenotype. Neurology. May 10 2005;64(9):1635-7. [Medline].

  9. Cardiovascular health supervision for individuals affected by Duchenne or Becker muscular dystrophy. Pediatrics. Dec 2005;116(6):1569-73. [Medline]. [Full Text].

  10. Emery AE, Skinner R. Clinical studies in benign (Becker type) X-linked muscular dystrophy. Clin Genet. Oct 1976;10(4):189-201. [Medline].

  11. Holloway SM, Wilcox DE, Wilcox A, et al. Life expectancy and death from cardiomyopathy amongst carriers of Duchenne and Becker muscular dystrophy in Scotland. Heart. Oct 11 2007;[Medline].

  12. Young HK, Barton BA, Waisbren S, et al. Cognitive and Psychological Profile of Males With Becker Muscular Dystrophy. J Child Neurol. Dec 3 2007;[Medline].

  13. Grootenhuis MA, de Boone J, van der Kooi AJ. Living with muscular dystrophy: health related quality of life consequences for children and adults. Health Qual Life Outcomes. 2007;5:31. [Medline]. [Full Text].

  14. Hayes J, Veyckemans F, Bissonnette B. Duchenne muscular dystrophy: an old anesthesia problem revisited. Paediatr Anaesth. Feb 2008;18(2):100-6. [Medline].

  15. Duan D. Myodys, a full-length dystrophin plasmid vector for Duchenne and Becker muscular dystrophy gene therapy. Curr Opin Mol Ther. Feb 2008;10(1):86-94. [Medline].

  16. Stöllberger C, Finsterer J. Worsening of heart failure in Becker muscular dystrophy after nonsteroidal anti-inflammatory drugs. South Med J. Apr 2005;98(4):478-80. [Medline].

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Further Reading

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Keywords

Becker muscular dystrophy, BMD, muscular dystrophy, X-linked dystrophinopathy, childhood muscular dystrophy, Duchenne muscular dystrophy, DMD, DMD-related dilated cardiomyopathy

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Contributor Information and Disclosures

Author

Benjamin R Mandac, MD, Chief of Physical Medicine and Rehabilitation, Medical Director of Pediatric Rehabilitation, Kaiser Permanente at Santa Clara
Benjamin R Mandac, MD is a member of the following medical societies: American Academy for Cerebral Palsy and Developmental Medicine and American Academy of Physical Medicine and Rehabilitation
Disclosure: Nothing to disclose.

Medical Editor

Elizabeth A Moberg-Wolff, MD, Associate Professor and Pediatric PM&R Fellowship Director, Department of Physical Medicine and Rehabilitation, Medical College of Wisconsin; Program Director, Tone Management and Mobility, Department of Physical Medicine and Rehabilitation, Children's Hospital of Wisconsin
Elizabeth A Moberg-Wolff, MD is a member of the following medical societies: American Academy of Cerebral Palsy and Developmental Medicine and American Academy of Physical Medicine and Rehabilitation
Disclosure: Medtronic Neurological Grant/research funds Speaking and teaching

Pharmacy Editor

Francisco Talavera, PharmD, PhD, Senior Pharmacy Editor, eMedicine
Disclosure: Nothing to disclose.

Managing Editor

Kat Kolaski, MD, Assistant Professor, Departments of Orthopedic Surgery and Pediatrics, Wake Forest University School of Medicine
Kat Kolaski, MD is a member of the following medical societies: American Academy for Cerebral Palsy and Developmental Medicine and American Academy of Physical Medicine and Rehabilitation
Disclosure: Nothing to disclose.

CME Editor

Kelly L Allen, MD, Consulting Staff, Department of Physical Medicine and Rehabilitation, Lourdes Regional Rehabilitation Center, Our Lady of Lourdes Medical Center
Disclosure: Nothing to disclose.

Chief Editor

Denise I Campagnolo, MD, MS, Director of Multiple Sclerosis Clinical Research and Staff Physiatrist, Barrow Neurology Clinics, St. Joseph's Hospital and Medical Center; Investigator for Barrow Neurology Clinics; Director, NARCOMS Project for Consortium of MS Centers, Phoenix
Denise I Campagnolo, MD, MS is a member of the following medical societies: Alpha Omega Alpha, American Association of Neuromuscular and Electrodiagnostic Medicine, American Paraplegia Society, Association of Academic Physiatrists, and Consortium of Multiple Sclerosis Centers
Disclosure: Teva Neuroscience Honoraria Speaking and teaching; Serono-Pfizer Honoraria Speaking and teaching

 
 
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