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Adult Spinal Muscular Atrophy

Atrophy Myelopathic Muscular

Adult spinal muscular atrophy is a genetic neurodegenerative disorder characterized by muscle wasting and weakness. In adults, normal life expectancy is achieved, as only mild weakness may be encountered. The diagnosis rests on confirming genetic mutations.


Presentation

Adult spinal muscular atrophy or spinal muscular atrophy (SMA) type 4 usually begins to appear at 30 years of age and has a relatively benign course [1]. The clinical features of this disease are very similar to SMA type 3, although the adult version is less severe. Life expectancy is normal in such patients [2]. Type 1 and type 2 SMA can occur at any age between birth and 2 years.

Patients classically present with an asymmetric weakness of the proximal muscles of the arms and legs, resulting in hampering of the quality of life [3]. Over time, the muscle wasting spreads to the other limb muscles before involving the central portions of the body. The weakness is associated with pain, in both the normal and affected muscles. Tremors and twitchings are also known to occur [4].

Involvement of the muscles of the thorax may result in respiratory compromise. The affliction of the brainstem may lead to bulbar symptoms such as dysphagia and dysarthria. There are usually no other central nervous system manifestations present. Reports have shown that these patients exhibit a higher degree of intelligence.

The examination may show all the characteristic findings of a lower motor neuron disease, namely absent/decreased reflexes, hypotonia, flaccid paralysis and muscle fasciculations.

Difficulty Walking
  • The mobility component is paid to people who have difficulty walking and in using public transport; the personal care component is paid to those who need help with such tasks as bathing and dressing.[daneverard.co.uk]
  • Someone with the condition may have: weakness in the hands and feet difficulty walking shaking and twitching muscles Type 4 SMA gets slowly worse over time, but doesn't normally cause problems with breathing or swallowing.[nhs.uk]
  • These children show signs of clumsiness, difficulty walking, mild muscle weakness, and may be developmentally delayed. These children live long into their adult years.[chw.org]
  • These children show signs of clumsiness, difficulty walking, mild muscle weakness, and may be developmentally delayed. These children live long into their adult years. Type IV.[stanfordchildrens.org]
Dysphagia
  • The affliction of the brainstem may lead to bulbar symptoms such as dysphagia and dysarthria. There are usually no other central nervous system manifestations present. Reports have shown that these patients exhibit a higher degree of intelligence.[symptoma.com]
  • Dysphagia may be present. Most children are confined to a wheelchair by age 2 to 3 yr. The disorder is often fatal in early life, frequently resulting from respiratory complications.[merckmanuals.com]
  • […] associated with names of investigators such as Santavuori-Haltia, Jansky-Bielschowsky, Batten, Spielmeyer-Vogt, Kufs Opitz G/BBB Syndrom ( 1 Files ) Erkrankung : Opitz G/BBB Syndrom ICD 10: Q87.8 Synonyme : Hypertelorism-hypospadias syndrome, hypospadias-dysphagia[orphananesthesia.eu]
Diarrhea
Delayed Gastric Emptying
  • Gastrointestinal studies showed no evidence of peristaltic contractions in the rectum, delayed gastric emptying, and abnormal jejunal manometry with altered propagation of the migrating myoelectrical complex.[ncbi.nlm.nih.gov]
Muscular Atrophy
  • Differential diagnosis usually involves the other spinal muscle atrophies which include the X-linked spinal muscular atrophy, distal spinal muscular atrophy, autosomal dominant spinal muscular atrophy and juvenile asymmetric segmental spinal muscular[symptoma.com]
  • atrophy Spinal muscular atrophy Spinal muscular atrophy Spinal muscular atrophy Spinal muscular atrophy Spinal Muscular Atrophy 3 Spinal Muscular Atrophy Association of Australia Inc. spinal muscular atrophy I spinal muscular atrophy III spinal muscular[medical-dictionary.thefreedictionary.com]
  • Diagnosis - Adult-onset spinal muscular atrophy Prognosis - Adult-onset spinal muscular atrophy Treatment - Adult-onset spinal muscular atrophy Resources - Adult-onset spinal muscular atrophy Not supplied.[checkorphan.org]
  • The diagnosis of adult spinal muscular atrophy (SMA) was made when electromyography showed large rapidly firing motor unit-potentials, positive waves, and fibrillation potentials, and when muscle biopsy of the quadriceps revealed severe alterations consistent[ncbi.nlm.nih.gov]
  • What is spinal muscular atrophy adult type? Spinal Muscular Atrophy Adult Type is a condition that affects the nerve cells (motor neurons) in your spinal cord. Onset of this condition is usually after 30 years of age.[patientslikeme.com]
Muscle Weakness
  • SMA4 is usually considered in an adult who begins to have proximal muscle weakness. Genetic testing of the SMN1 gene is used to confirm the diagnosis. Muscle weakness seen in SMA4 is similar to the muscle weakness seen in other genetic conditions.[resourcerepository.org]
  • SMAPAD is characterized by proximal muscle weakness that begins in the lower limbs and then progresses to upper limbs, onset in late adulthood (after third decade) and a benign course.[uniprot.org]
  • The nerve cells tend to cause muscle weakness, tremor, and twitching. Common symptoms reported by people with spinal muscular atrophy adult type Reports may be affected by other conditions and/or medication side effects.[patientslikeme.com]
  • Arms should be regularly checked to maintain a good range of movement, particularly in the shoulders when muscle weakness prevents full elevation of the arms.[daneverard.co.uk]
Myopathy
  • Over the years, patients labeled earlier as SMA have had their diagnoses revised to more treatable conditions including syringomyelia, amyotrophic lateral sclerosis, myopathy, axonal neuropathies and herniated lumbar discs.[symptoma.com]
  • , Multicore myopathy, Multiminicore myopathy, Minicore myopathy with hand involvement, antenatal onset minicore myopathy with arthrogryposis, Minicore myopathy with external ophthalmoplegia, Multicore myopathy with external ophthalmoplegia, Multiminicore[orphananesthesia.eu]
  • Differential diagnosis Motor neurone disease Primary lateral sclerosis Muscular dystrophy Congenital myopathies Disorders of carbohydrate metabolism ( glycogen storage diseases ) Myasthenia gravis Poliomyelitis Investigations Blood tests Creatine kinase[patient.info]
  • The database (known as the UMD-SMN1 France database) is financed by AFM (Association Française contre les Myopathies) and is a result of a major national effort involving all French molecular diagnostic laboratories and reference centers for neuromuscluar[treat-nmd.eu]
Muscle Twitch
  • The disorder slowly progressed to include cramps and muscle twitches.[ncbi.nlm.nih.gov]
  • twitching first noted in late teens or early adulthood There are other diseases that are similar to spinal muscular atrophy, but have different genetic causes.[togetherinsma.com]
  • twitching first noted in late teens or adulthood To learn how different aspects of care may relate to the signs and symptoms of SMA, click here .[togetherinsma-hcp.com]
Tremor
  • Tremors and twitchings are also known to occur. Involvement of the muscles of the thorax may result in respiratory compromise. The affliction of the brainstem may lead to bulbar symptoms such as dysphagia and dysarthria.[symptoma.com]
  • The nerve cells tend to cause muscle weakness, tremor, and twitching. Common symptoms reported by people with spinal muscular atrophy adult type Reports may be affected by other conditions and/or medication side effects.[patientslikeme.com]
  • Other symptoms include tremors, twitching, and mild breathing issues. SMA4 is caused by changes (mutations) in the SMN1 gene. This gene provides the instructions to make a protein that helps motor neurons work.[resourcerepository.org]
  • Symptoms – Children can stand alone and walk, but may struggle with: getting up from a sitting position tremor in fingers respiratory infections Children with SMA Type III usually remain mobile well into adulthood.[griswoldhomecare.com]
  • Fine tremors of the face are present in over 90% of patients. Type 2 diabetes mellitus, hand tremor, and infertility can also occur.[encyclopedia.com]
Limb Weakness
  • As the disease progresses patients may notice limb weakness starting in the pelvis or shoulders, or weakness of the facial and tongue muscles. Symptoms of SMA-LED often develop in infancy or early childhood.[cedars-sinai.edu]
  • weakness, hypotonia Bulbar palsy Late Microcephaly Oculomotor defects: strabismus , nystagmus , oculomotor apraxia Cognitive defects Life expectancy 1 year Diagnostics Genetic testing : best initial and confirmatory test Further tests Laboratory tests[amboss.com]
  • In addition to muscle weakness, clinical features include head lag, poor sucking and swallowing, weak cry, proximal limb weakness, and lack of reflexes. Affected children never raise their head, roll over, or walk.[encyclopedia.com]
Absent Deep Tendon Reflex
  • Results in muscle weakness and atrophy The onset varies from before birth until adulthood The weakness is symmetric and progressive Contractures, usually mild Anterior horn cell involvement, apparent due to tongue fasciculations and absent deep tendon[en.wikibooks.org]
Areflexia
  • Patients typically present during infancy or early childhood with progressive weakness, hypotonia , muscle atrophy , hyporeflexia/areflexia, and varying degrees of bulbar weakness.[amboss.com]
Average Intelligence
  • The brain is not affected, and they have been tested to have at least average to above average intelligence. Please do not make the mistake of treating them as mentally impaired!![smasupport.com]

Workup

Diagnosis of this disease is dependent on the anamnestic data. Amongst laboratory tests that may be performed, creatine kinase is the most useful, with elevated levels of the enzyme found. In some patients, the enzyme levels may be normal.

Genetic tests may be performed both prenatally and postnatally to check for deletions involving the SMN1 gene [5].

Electrocardiograms (ECGs) are usually normal in these patients [6].

A variety of other neuromuscular diseases may present in a similar manner. Differentiation is done by electrophysiological tests that demonstrate a reduction of transmitted nerve signals [7] [8]. Sensory signals are usually normal in adult spinal muscular atrophy. Tests involving compound motor action potential may also be performed for diagnosis.

Muscle biopsy is another test that may help in differentiating adult spinal muscular atrophy from other similar muscular diseases [9] [10]. These characteristically show atrophy of the muscle fibers with compensatory hypertrophy.

Differential diagnosis usually involves the other spinal muscle atrophies which include the X-linked spinal muscular atrophy, distal spinal muscular atrophy, autosomal dominant spinal muscular atrophy and juvenile asymmetric segmental spinal muscular atrophy. Postpolio syndrome and multifocal motor neuropathy are the other conditions that may present in a similar fashion.

There is a potential for patients with adult spinal muscular atrophy to be misdiagnosed due to the overlapping of clinical features. Over the years, patients labeled earlier as SMA have had their diagnoses revised to more treatable conditions including syringomyelia, amyotrophic lateral sclerosis, myopathy, axonal neuropathies and herniated lumbar discs. It is hence, recommended that patients be followed up for a long duration to establish the correct diagnosis.

Treatment

  • Treatment options focus on addressing the muscle weakness and can include physical therapy. If you or your child has been diagnosed with SMA4, talk with a doctor about all treatment options.[resourcerepository.org]
  • The sponsor is receiving a rare pediatric disease priority review voucher under a program intended to encourage development of new drugs and biologics for the prevention and treatment of rare pediatric diseases.[news-medical.net]
  • It is not in any way intended to be used as a substitute for professional medical advice, diagnosis, treatment or care. Our staff consists of biologists and biochemists that are not trained to give medical advice .[uniprot.org]
  • WHAT TREATMENT IS THERE FOR ADULT ONSET SMA? Research into SMA is progressing, but at present there is no known cure, and no treatment which will repair the damage to the anterior horn cells, or reverse the weakening of the muscles.[daneverard.co.uk]

Prognosis

  • Diagnosis - Adult-onset spinal muscular atrophy Prognosis - Adult-onset spinal muscular atrophy Treatment - Adult-onset spinal muscular atrophy Resources - Adult-onset spinal muscular atrophy Not supplied.[checkorphan.org]
  • prognosis of these patients 7,8 .[radiopaedia.org]
  • The prognosis is poor for babies with SMA Type I: most die within the first two years.[bionews-tx.com]
  • If a child reaches 18 months of age before symptoms begin, the prognosis is good. Symptoms will include reduced muscle strength and eventually, patients will lose the ability to walk.[babymed.com]
  • These subgroup classifications are useful for prognosis and management.[en.wikibooks.org]

Etiology

  • Etiology Pathophysiology Clinical features The most common causes of death among patients with SMA are respiratory insufficiency (due to respiratory muscle weakness ) and aspiration pneumonia (due to bulbar weakness)![amboss.com]
  • Etiology As for the other forms of SMA, SMA4 has been associated with deletions in the SMN1 gene (5q12.2-q13.3) encoding the SMN (survival motor neuron) protein.[orpha.net]
  • Etiology [ edit ] Mode of inheritance: SMA is an autosomal recessive disorder Chromosome location: Chromosomal locus 5q11-q13 Molecular Genetics: SMN (survival motor neuron) has been identified as the primary SMA-determining gene The SMN gene is very[en.wikibooks.org]

Epidemiology

  • Epidemiology References: [1] [2] [3] Epidemiological data refers to the US, unless otherwise specified.[amboss.com]
  • Summary Epidemiology Prevalence is estimated at around 1/300,000. Clinical description SMA4 usually manifests in the second or third decade of life.[orpha.net]
  • SMA with respiratory distress (SMARD1) Inheritance is autosomal recessive due to mutations in the IGHMBP2 gene on chromosome 11q13. [ 9 ] Epidemiology The estimated incidence is between 1 in 6,000 and 1 in 10,000 live births and the carrier frequency[patient.info]
  • […] adult patients with SMA type III or IV found that spinal cord gray matter had considerably atrophied between C2 and C6, while, possibly owing to an adaptive mechanism, the gray matter had grown denser in the motor and extramotor cortical regions. [5] Epidemiology[emedicine.medscape.com]
Sex distribution
Age distribution

Pathophysiology

  • Etiology Pathophysiology Clinical features The most common causes of death among patients with SMA are respiratory insufficiency (due to respiratory muscle weakness ) and aspiration pneumonia (due to bulbar weakness)![amboss.com]
  • Pathophysiology Spinal muscular atrophy (SMA) types I-III Inheritance is autosomal recessive. Affected individuals have two copies of the altered gene. Those who carry one copy are usually unaffected carriers.[patient.info]
  • Pathophysiology In 1995, the spinal muscular atrophy disease-causing gene, termed the survival motor neuron ( SMN ), was discovered. [9] Each individual has 2 SMN genes, SMN1 and SMN2 .[emedicine.medscape.com]
  • Related Medscape Reference topics: Focal Muscular Atrophies Spinal Muscle Atrophy Spinal Muscular Atrophy Related Medscape resource: Resource Center Spinal Disorders Pathophysiology Spinal muscular atrophy (SMA) is caused by successive motor unit degeneration[emedicine.medscape.com]

Prevention

  • Prevention - Adult-onset spinal muscular atrophy Genetic counseling is recommended for people with a family history of spinal muscular atrophy who want to have children.[checkorphan.org]
  • The sponsor is receiving a rare pediatric disease priority review voucher under a program intended to encourage development of new drugs and biologics for the prevention and treatment of rare pediatric diseases.[news-medical.net]
  • Maintain a good joint range and prevent asymmetry and scoliosis (curvature of the spine) Encourage good respiratory function. Assessments.[daneverard.co.uk]
  • Improve Your Chances by Hiring a Disability Attorney If you've been denied benefits for muscular atrophy that prevents you from working, an experienced disability attorney can help you navigate the confusing disability appeals process.[disabilitysecrets.com]
  • Orthopedic surgical interventions such as tendon transfer or spinal surgery can prevent disability in patients with expected prolonged survival.[encyclopedia.com]

References

Article

  1. Wang CH1, Finkel RS, Bertini ES, et al. Consensus statement for standard of care in spinal muscular atrophy. J Child Neurol. 2007;22(8):1027-1049.
  2. Baioni MT, Ambiel CR. Spinal muscular atrophy: diagnosis, treatment and future prospects. J Pediatr (Rio J). 2010;86(4):261-270.
  3. Prior TW, Russman BS. Spinal Muscular Atrophy. 2000 Feb 24 [Updated 2013 Nov 14]. In: Pagon RA, Adam MP, Ardinger HH, et al., editors. GeneReviews® [Internet]. Seattle (WA): University of Washington, Seattle; 1993-2016.
  4. Joynt R, Griggs R. Clinical Neurology. Philadelphia: Lippincott; 1997. Vol 4: 11-5.
  5. Arnold WD, Kassar D, Kissel JT. Spinal Muscular Atrophy: Diagnosis and Management in a New Therapeutic Era. Muscle Nerve. 2015;51(2):157-167.
  6. Palladino A, Passamano L, Taglia A, et al. Cardiac involvement in patients with spinal muscular atrophies. Acta Myol. 2011 Dec. 30(3):175-8.
  7. Hausmanowa-Petrusewicz I, Karwanska A. Electromyographic findings in different forms of infantile and juvenile proximal spinal muscular atrophy. Muscle Nerve. 1986 Jan. 9(1):37-46.
  8. Krivickas LS. Electrodiagnosis in neuromuscular disease. Phys Med Rehabil Clin N Am. 1998 Feb. 9(1):83-114, vi.
  9. Buchthal F, Olsen PZ. Electromyography and muscle biopsy in infantile spinal muscular atrophy. Brain. 1970. 93(1):15-30.
  10. Dubowitz V. Muscle disorders in childhood. Major Probl Clin Pediatr. 1978. 16:iii-xiii, 1-282.

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Last updated: 2018-06-21 19:32