Pseudohypertrophy

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Pseudohypertrophy
Other namesfalse enlargement
Drawing of boy with Duchenne muscular dystrophy.png
Drawing of seven-year-old boy with Duchenne muscular dystrophy. There is pseudohypertrophy of the lower limbs.
Symptoms Weakness
Causesmuscle disease, nerve disease

Pseudohypertrophy, or false enlargement, is an increase in the size of an organ due to infiltration of a tissue not normally found in that organ. [1] It is commonly applied to enlargement of a muscle due to infiltration of fat or connective tissue, [2] famously in Duchenne muscular dystrophy. This is in contrast with typical muscle hypertrophy, in which the muscle tissue itself increases in size. [2] Because pseudohypertrophy is not a result of increased muscle tissue, the muscles look bigger but are actually atrophied and thus weaker. [2] [3] Pseudohypertrophy is typically the result of a disease, which can be a disease of muscle or a disease of the nerve supplying the muscle. [2]

Contents

Causes of pseudohypertrophy include muscle diseases: dystrophinopathies, limb-girdle muscular dystrophies, metabolic myopathy, Dystrophic myotonias, Non-dystrophic myotonias, endocrine disorders, parasitic muscle conditions, amyloid and sarcoid myopathy, and granulomatous myositis. [2]

Neurological causes include radiculopathy, poliomyelitis, Charcot-Marie-Tooth disease, spinal muscular atrophy. [2]

In pseudohypertrophy where the atrophied muscle tissue has been infiltrated by fat tissue, upon palpitation the seemingly large muscles feel doughy. [3]

Not all muscles infiltrated by fat or other tissue are pseudohypertrophic. In muscular steatosis, sometimes the muscles may appear a normal or a slender size, even though the atrophied muscle has been infiltrated with fat tissue, such as the calf muscles in Bethlem myopathy 1. [4] [5] [6] [7] [8] In myosclerosis, the muscle is infiltrated with connective tissue and fibrosis, having a firm, "woody" feel upon palpitation, with the muscles appearing slender. [9] [10]

Etymology

Pseudohypertrophy can be broken up into the following roots, suffixes, and prefixes:

The term was used by Duchenne de Boulogne in his description of Duchenne muscular dystrophy in one of his works "paralysie musculaire pseudo-hypertrophique." [11]

Other names

As well as being known as 'false enlargement,' when the muscle has been infiltrated by fat tissue, historically it has also been called muscular steatosis, pseudohypertrophic atrophy, lipomatous pseudohypertrophy, interstitial lipomatosis, lipomatous muscular dystrophy, or atrophia lipomatosa. [12] It is also known as fatty atrophy of muscle (not to be confused with fat atrophy, which is atrophy of adipose tissue), as muscle tissue is replaced by fat tissue, the actual muscle atrophies while the fat tissue replaces the bulk. [13]

Related Research Articles

Kocher–Debré–Semelaigne syndrome(KDSS) is hypothyroidism in infancy or childhood characterised by lower extremity or generalized muscular hypertrophy (Herculean appearance), myxoedema, short stature, and cognitive impairment.

<span class="mw-page-title-main">Muscular dystrophy</span> Genetic disorder

Muscular dystrophies (MD) are a genetically and clinically heterogeneous group of rare neuromuscular diseases that cause progressive weakness and breakdown of skeletal muscles over time. The disorders differ as to which muscles are primarily affected, the degree of weakness, how fast they worsen, and when symptoms begin. Some types are also associated with problems in other organs.

<span class="mw-page-title-main">Dystrophin</span> Rod-shaped cytoplasmic protein

Dystrophin is a rod-shaped cytoplasmic protein, and a vital part of a protein complex that connects the cytoskeleton of a muscle fiber to the surrounding extracellular matrix through the cell membrane. This complex is variously known as the costamere or the dystrophin-associated protein complex (DAPC). Many muscle proteins, such as α-dystrobrevin, syncoilin, synemin, sarcoglycan, dystroglycan, and sarcospan, colocalize with dystrophin at the costamere. It has a molecular weight of 427 kDa

<span class="mw-page-title-main">Becker muscular dystrophy</span> Genetic muscle disorder

Becker muscular dystrophy is an X-linked recessive inherited disorder characterized by slowly progressing muscle weakness of the legs and pelvis. It is a type of dystrophinopathy. This is caused by mutations in the dystrophin gene, which encodes the protein dystrophin. Becker muscular dystrophy is related to Duchenne muscular dystrophy in that both result from a mutation in the dystrophin gene, but has a milder course.

<span class="mw-page-title-main">Muscle biopsy</span> Procedure in which a piece of muscle tissue is removed from an organism and examined microscopically

In medicine, a muscle biopsy is a procedure in which a piece of muscle tissue is removed from an organism and examined microscopically. A muscle biopsy can lead to the discovery of problems with the nervous system, connective tissue, vascular system, or musculoskeletal system.

In medicine, myopathy is a disease of the muscle in which the muscle fibers do not function properly. This results in muscular weakness. Myopathy means muscle disease. This meaning implies that the primary defect is within the muscle, as opposed to the nerves or elsewhere. Muscle cramps, stiffness, and spasm can also be associated with myopathy.

<span class="mw-page-title-main">Neuromuscular disease</span> Medical condition

A neuromuscular disease is any disease affecting the peripheral nervous system (PNS), the neuromuscular junctions, or skeletal muscles, all of which are components of the motor unit. Damage to any of these structures can cause muscle atrophy and weakness. Issues with sensation can also occur.

<span class="mw-page-title-main">Congenital muscular dystrophy</span> Medical condition

Congenital muscular dystrophies are autosomal recessively-inherited muscle diseases. They are a group of heterogeneous disorders characterized by muscle weakness which is present at birth and the different changes on muscle biopsy that ranges from myopathic to overtly dystrophic due to the age at which the biopsy takes place.

<span class="mw-page-title-main">Muscle hypertrophy</span> Enlargement or overgrowth of a muscle organ

Muscle hypertrophy or muscle building involves a hypertrophy or increase in size of skeletal muscle through a growth in size of its component cells. Two factors contribute to hypertrophy: sarcoplasmic hypertrophy, which focuses more on increased muscle glycogen storage; and myofibrillar hypertrophy, which focuses more on increased myofibril size. It is the primary focus of bodybuilding-related activities.

<span class="mw-page-title-main">Bethlem myopathy</span> Medical condition

Bethlem myopathy is predominantly an autosomal dominant myopathy, classified as a congenital form of muscular dystrophy. There are two types of Bethlem myopathy, based on which type of collagen is affected.

<span class="mw-page-title-main">Collagen, type VI, alpha 2</span> Mammalian protein found in Homo sapiens

Collagen alpha-2(VI) chain is a protein that in humans is encoded by the COL6A2 gene.

<span class="mw-page-title-main">Collagen, type VI, alpha 3</span> Mammalian protein found in Homo sapiens

Collagen alpha-3(VI) chain is a protein that in humans is encoded by the COL6A3 gene. This protein is an alpha chain of type VI collagen that aids in microfibril formation. As part of type VI collagen, this protein has been implicated in Bethlem myopathy, Ullrich congenital muscular dystrophy (UCMD), and other diseases related to muscle and connective tissue.

<span class="mw-page-title-main">Muscle contracture</span> Permanent shortening of a muscle

Muscle contractures can occur for many reasons, such as paralysis, muscular atrophy, and forms of muscular dystrophy. Fundamentally, the muscle and its tendons shorten, resulting in reduced flexibility.

<span class="mw-page-title-main">Metabolic myopathy</span> Type of myopathies

Metabolic myopathies are myopathies that result from defects in biochemical metabolism that primarily affect muscle. They are generally genetic defects that interfere with muscle's ability to create energy, causing a low ATP reservoir within the muscle cell.

<span class="mw-page-title-main">Ullrich congenital muscular dystrophy</span> Medical condition

Ullrich congenital muscular dystrophy (UCMD) is a form of congenital muscular dystrophy. There are two forms: UCMD1 and UCMD2.

Collagen VI (ColVI) is a type of collagen primarily associated with the extracellular matrix of skeletal muscle. ColVI maintains regularity in muscle function and stabilizes the cell membrane. It is synthesized by a complex, multistep pathway that leads to the formation of a unique network of linked microfilaments located in the extracellular matrix (ECM). ColVI plays a vital role in numerous cell types, including chondrocytes, neurons, myocytes, fibroblasts, and cardiomyocytes. ColVI molecules are made up of three alpha chains: α1(VI), α2(VI), and α3(VI). It is encoded by 6 genes: COL6A1, COL6A2, COL6A3, COL6A4, COL6A5, and COL6A6. The chain lengths of α1(VI) and α2(VI) are about 1,000 amino acids. The chain length of α3(VI) is roughly a third larger than those of α1(VI) and α2(VI), and it consists of several spliced variants within the range of 2,500 to 3,100 amino acids.

Hoffmann syndrome is a rare form of hypothyroid myopathy and is not to be confused with Werdnig-Hoffmann disease.

Sunil Pradhan is an Indian neurologist, medical researcher and writer, known for the invention of two electrophysiological techniques. He has also described five medical signs, of which one related to Duchenne muscular dystrophy is known as Pradhan Sign, and the others associated with facioscapulohumeral muscular dystrophy (FSHD) and similar neuro diseases. The Government of India awarded him the Padma Shri, the fourth highest civilian award, in 2014 for his contributions to the field of neuroscience.

<span class="mw-page-title-main">Pseudoathletic appearance</span> Medical sign

Pseudoathletic appearance is a medical sign meaning to have the false appearance of a well-trained athlete due to pathology instead of true athleticism. It is also referred to as a Herculean or bodybuilder-like appearance. The pathology may be the result of muscle inflammation (swelling), muscle hyperplasia, muscle hypertrophy, muscle pseudohypertrophy, or symmetrical subcutaneous deposits of fat or other tissue.

References

  1. ↑ Adami, John George (1908). The Principles of pathology (1 ed.). p. 540. Retrieved 23 April 2022.
  2. 1 2 3 4 5 6 Walters, J (October 2017). "Muscle hypertrophy and pseudohypertrophy". Practical Neurology. 17 (5): 369–379. doi: 10.1136/practneurol-2017-001695 . PMID   28778933. S2CID   6444771.
  3. 1 2 Tyler, Frank H. (1950-03-01). "STUDIES IN DISORDERS OF MUSCLE: III. "Pseudohypertrophy" of Muscle in Progressive Muscular Dystrophy and Other Neuromuscular Diseases". Archives of Neurology & Psychiatry. 63 (3): 425. doi:10.1001/archneurpsyc.1950.02310210071005. ISSN   0096-6754.
  4. ↑ Nalini, A.; Gayathri, N. (2010-07-01). "Bethlem myopathy: A study of two families". Neurology India. 58 (4): 665–666. doi: 10.4103/0028-3886.68684 . ISSN   0028-3886. PMID   20739820.
  5. ↑ Bönnemann, Carsten G. (2011-06-21). "The collagen VI-related myopathies: muscle meets its matrix". Nature Reviews. Neurology. 7 (7): 379–390. doi:10.1038/nrneurol.2011.81. ISSN   1759-4766. PMC   5210181 . PMID   21691338.
  6. ↑ Suh, B.C.; Choi, Y.C.; Kim, S.M.; Choi, B.O.; Shim, D.; Lee, D.H.; Sunwoo, I. (2006). "A Family of Bethlem Myopathy". Journal of the Korean Neurological Association. 24: 614–617. S2CID   74251729.
  7. ↑ Souza, Paulo Victor Sgobbi de; Bortholin, Thiago; Pinheiro, Jhonatan Rafael Siqueira; Naylor, Fernando George Monteiro; Pinto, Wladimir Bocca Vieira de Rezende; Oliveira, Acary Souza Bulle (2017-10-01). "Collagen type VI-related myopathy". Practical Neurology. 17 (5): 406–407. doi:10.1136/practneurol-2017-001661. ISSN   1474-7758. PMID   28578317.
  8. ↑ Telles, Juliana Aparecida Rhein; Voos, Mariana Calil; Anequini, Isabella Pessa; Favero, Francis Meire; Silva, Thiago Henrique; Caromano, Fátima Aparecida (June 2018). "Genetic and functional differences between Bethlem myopathy and Ullrich congenital muscular dystrophy - case studies". Cadernos de Pós-Graduação em Distúrbios do Desenvolvimento. 18 (1): 148–163. doi:10.5935/cadernosdisturbios.v18n1p148-163. ISSN   1519-0307.
  9. ↑ Bradley, W. G.; Hudgson, P.; Gardner-Medwin, D.; Walton, J. N. (August 1973). "The syndrome of myosclerosis". Journal of Neurology, Neurosurgery, and Psychiatry. 36 (4): 651–660. doi:10.1136/jnnp.36.4.651. ISSN   0022-3050. PMC   494424 . PMID   4793163.
  10. ↑ Merlini, L.; Martoni, E.; Grumati, P.; Sabatelli, P.; Squarzoni, S.; Urciuolo, A.; Ferlini, A.; Gualandi, F.; Bonaldo, P. (2008-10-14). "Autosomal recessive myosclerosis myopathy is a collagen VI disorder". Neurology. 71 (16): 1245–1253. doi:10.1212/01.wnl.0000327611.01687.5e. ISSN   1526-632X. PMID   18852439.
  11. ↑ Cros, D; Harnden, P; Pellissier, JF; Serratrice, G (January 1989). "Muscle hypertrophy in Duchenne muscular dystrophy. A pathological and morphometric study". Journal of Neurology. 236 (1): 43–7. doi:10.1007/BF00314217. PMID   2915226. S2CID   23619631.
  12. ↑ Swatland, Howard (January 1974). "Developmental disorders of skeletal muscle in cattle, pigs and sheep". The Veterinary Bulletin. 44 (4): 193–194 – via ResearchGate.
  13. ↑ Morrow, J.; Sinclair, C. D. J.; Fischmann, A.; Thornton, J. S.; Yousry, T. A.; Reilly, M. M.; Hanna, M. G. (2012-03-01). "1700 MRI quantification of lower limb muscle fatty atrophy: a potential outcome measure in chronic neuromuscular diseases". Journal of Neurology, Neurosurgery & Psychiatry. 83 (3): e1. doi:10.1136/jnnp-2011-301993.32. ISSN   0022-3050.
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