additional information that can be usefull to everyone :)

1. Spinal Muscular
Atrophy
Allelieh Javier Capistrano, RT
Pediatric Respiratory Therapist
Section of Pulmonary Medicine
Philippine Children’s Medical Center

2. What is SMA?
 Spinal muscular atrophy (SMA) is a group of inherited
neuromuscular diseases that attack motor neurons,
which control the movement of voluntary muscles.
This disease causes anterior horn cells (lower motor
neurons) in the base of the brain and spinal cord to
gradually disintegrate.
 The disorder causes weakness and wasting of the
voluntary muscles.
 Weakness is often more severe in the legs than in the
arms.

3. What is SMA?
 Loss of function of spinal motor neurons
causing progressive weakness of muscles
 Muscles include extremities, respiratory
muscles
 Sensation is normal
 Brain function is
normal
http://kidshealth.org/parent/medical/bones/sma.html#

4. What is the lower motor neuron?

5. Types of SMA
 Infantile progressive spinal
muscular atrophy (SMA Type 1)
 Intermediate SMA (SMA Type 2)
 Juvenile SMA (SMA Type 3)
 Adult SMA (SMA Type 4)
 SMARD1
 Congenital SMA with
arthrogryposis

6. SMA Type 1
 Also known as, Werdnig-Hoffmann acute infantile,
non-sitters, occur birth up to 6 months (95% by 3
months)
 Severe, progressive muscle weakness and flaccid
or reduced muscle tone (hypotonia).
 Bulbar dysfunction includes poor suck ability,
reduced swallowing, and respiratory failure.
 Patients have no involvement of the extraocular
muscles, and facial weakness is often minimal or
absent.
 They have no evidence of cerebral involvement,
and infants appear alert.

7. SMA Type 1
 Impaired fetal movements are observed in 30% of cases
 60% of infants with SMA type I are floppy babies at birth.
Prolonged cyanosis may be noted at delivery.
 In some instances, the disease can cause fulminant
weakness in the first few days of life. Such severe
weakness and early bulbar dysfunction which has a
mean survival of 5.9 months.
 Affected children never sit or stand.
 In 95% of cases, infants die from complications of the
disease by 18 months.

8. SMA Type 2
 SMA type II (intermediate SMA, sitters) usually begin
between 6 - 18 months.
 Most common form of SMA
 Most common manifestation is developmental motor delay.
Infants with SMA type II often have difficulties with sitting
independently or failure to stand by 1 year of age.
 These children may learn to sit but will never be able to
stand or walk.

9. SMA type 2
 An unusual feature of the disease is a postural tremor
affecting the fingers. This is thought to be related to
fasciculations in the skeletal muscles
 Pseudohypertrophy of the gastrocnemius muscle,
musculoskeletal deformities, and respiratory failure can
occur.
 The lifespan of patients with SMA type II varies from 2
years to the third decade of life. Respiratory infections
account for most deaths.

10. SMA Type 3
 SMA type III (Kugelberg-Welander, chronic
juvenile, walkers) appear 18 months – adult.
 Slowly progressive proximal weakness. Most can
stand and walk but have trouble with motor skills,
such as going up and down stairs.
 Bulbar dysfunction occurs late in the disease.

11. SMA Type 3
 Patients may show evidence of
pseudohypertrophy.
 The disease progresses slowly, and the
overall course is mild. Many patients
have normal life expectancies.

12. SMA Type 4
 is the adult form of the disorder. Most people affected
by this type start having symptoms after age 35, and
these symptoms slowly get worse over time. Because
it develops slowly, many people with type IV SMA
don't know that they have it until years after
symptoms begin.

13. Spinal Muscular Atrophy with Respiratory
Distress Type 1 (SMARD1)
 In SMARD1, the predominating symptom is a severe
respiratory distress due to a paralysis of the diaphragm. Most
patients present show symptoms at the age of 1 to 6 months
with respiratory failure and progressive muscle weakness with
predominantly distal lower limb muscle involvement.

14. Spinal Muscular Atrophy with
Respiratory Distress Type 1
(SMARD1)
 In SMARD1, the predominating symptom is a severe
respiratory distress due to a paralysis of the diaphragm.
Most patients present show symptoms at the age of 1 to
6 months with respiratory failure and progressive muscle
weakness with predominantly distal lower limb muscle
involvement.

15. Congenital SMA with arthrogryposis
 Congenital SMA with arthrogryposis (persistent
contracture of joints with fixed abnormal posture of the
limb) is a rare disorder. Manifestations include severe
contractures, curvature of the spine, chest deformity,
respiratory problems, an unusually small jaw, and
drooping upper eyelids.

16. Congenital SMA with arthrogryposis

17. A Genetic Cause
 SMA is usually inherited. This means that both parents
must have an altered (mutated) or missing copy of the
gene involved in the disorder for a child to develop it.

18. A Genetic Cause
 Most cases of SMA are caused by a deficiency of a
special protein called SMN ("survival of motor neurons").
Motor neurons need this protein to function. The gene
that carries this protein is called SMN1. When each
parent passes onto their child a chromosome with a
mutated or missing SMN1 gene, the protein is not
produced and motor neurons die, leading to SMA.

19. A Genetic Cause
 The genetic defects associated with SMA types I-III are localized on chromosome
5q11.2-13.3.
 Mutations in the SMN gene result in a loss of function of the SMN protein.

20. Clinical Features (general for all types
of SMA)
 Progressive degeneration and loss of the lower motor
neurons (anterior horn cells) in the spinal cord and
sometimes in the brainstem nuclei.
 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 reflexes
 Respiratory failure
 Variable cranial nerve involvement: opthalmoplegia,
facial diplegia

21. Diagnosis

22. Diagnosis
 A diagnosis usually comes only after the child undergoes several
tests that rule out other diseases that cause similar symptoms.
These tests usually include:
 nerve conduction tests, such as an electromyogram (EMG)
 computed tomography (CT) scan
 magnetic resonance imaging (MRI)
 muscle tissue biopsy

23. Diagnosis
 To confirm an SMA diagnosis, the doctor will usually recommend a
blood test to look at the child's genes. If the SMN1 gene is missing
or imperfect, it will confirm the diagnosis of SMA. The doctor might
also recommend that parents and other members be screened for
the disorder, even if they've never had any symptoms.

24. Treatment
 Unfortunately, there is no cure for SMA. The treatment that children
receive for SMA varies, depending on their age and the severity of
symptoms. The goal of treatment is to relieve specific symptoms,
maintain function and enhance a child's mobility for as long as
possible, and maximize the child's independence and quality of life.

26. Prevention and Maintenance
 Today, much can be done for SMA patients in terms of medical and
in particular respiratory, nutritional and rehabilitation care. Physical
therapy and occupational therapy to promote and maintain motor skills.
 Monitoring of respiratory function, ventilatory support.

27. Respiratory Support
 Children with SMA commonly need help breathing when muscle
weakness begins to affect the respiratory muscles. Different
therapies can help a child breathe.
 Oxygen therapy
 Non-invasive positive pressure ventilation (NIPPV)
 BiPAP
 tracheostomy

28. Respiratory Support
 A critical factor in respiratory care is preventing infection,
especially pneumonia. Pneumonia is common in children
with SMA and is life threatening.

29. Respiratory Aids
 Cough Assist
 Chest physiotherapy
 Home suction
 Pulse oximeter
 Ambubag
 Nebulizer
 Bronchodilator, mucolytics,
anticholinergics

30. Conventional Respiratory therapy
 1. Oxygen administrated arbitrarily in concentrations that
maintain SaO2 well above 95%.
 2. Frequent airway suctioning via the tube.
 3. Supplemental oxygen increased when desaturations
occur.
 4. Ventilator weaning attempted at the expense of
hypercapnia.
 5. Extubation not attempted unless the patient appears
to be ventilator weaned.

31. Conventional Respiratory therapy
 6. Extubation to CPAP or low span bi-level positive airway pressure
and continued oxygen therapy.
 7. Deep airway suctioning by catheterizing the upper airway along
with postural drainage and chest physical therapy.
 8. With increasing CO2 retention or hypoxia supplemental oxygen is
increased and ultimately the patient is reintubated.
 9. Following re-intubation tracheostomy is thought to be the only
long-term option or following successful extubation bronchodilators
and ongoing routine chest physical therapy are used.
 10. Eventually discharged home with a tracheostomy, often
following a rehabilitation stay for family training.

32. Protocol for SMA
 1. Oxygen administration limited only to approach 95% SaO2.
 2. Mechanical insufflation-exsufflation used via the tube at 25 to 40
cm H2O to -25 to -40 cm H2O pressures up to every 10 minutes as
needed to reverse oxyhemoglobin desaturations due to airway
mucus accumulation and when there is auscultatory evidence of
secretion accumulation. Abdominal thrusts are applied during
exsufflation. Tube and upper airway are suctioned following use of
expiratory aids as needed.
 3. Expiratory aids used when desaturations occur.
 4. Ventilator weaning attempted without permitting hypercapnia.

33. Protocol for SMA
 5. Extubation attempted whether or not the patient is
ventilator weaned when meeting the following:
 A. Afebrile
 B. No supplemental oxygen requirement to maintain
SaO2 >94%
 C. Chest radiograph abnormalities cleared or clearing
 D. Any respiratory depressants discontinued
 E. Airway suctioning required less than 1-2x/eight
hours

34. Nutritional Support
 SMA can affect the muscles used for chewing, sucking,
and swallowing. This can cause a child to become
malnourished or develop pneumonia if the child inhales
food or liquids while eating. Some children do better by
eating small, frequent meals throughout the day instead
of having three large meals.
 Some children with SMA are at risk for obesity if they
consume too many calories for their activity levels and
they can't exercise to effectively burn the calories.
Ongoing consultation with a nutritionist is necessary to
ensure adequate nutrition that doesn't overload a child
with unnecessary calories.

35. Nutritional Support
 Children who can't swallow or suck must be fed in
another way to ensure that they're receiving enough
nutrition. Sometimes, they have a tube inserted into the
stomach to help them eat. Through this tube, called a
gastrostomy tube, they can receive a nutritionally sound
liquid diet.

36. Function and Mobility

37. Function and Mobility
 Many children with SMA benefit greatly from physical
and occupational therapies, which help to maintain
function and mobility and enhance quality of life for as
long as possible. In some cases, tools can help make
these tasks easier, such as:
 leg braces, standing frames, canes, and walkers, which provide
stability and improve mobility
 electric wheelchairs with customized controls
 specialized seats to use in school
 tools for using computers and phones and controlling other
home electronics, such as the TVs and lights
 tools to aid educational activities, such as writing and drawing

38. Spinal Deformity
 Children who develop spinal deformities need to wear a
splint, brace, or corset to straighten their backs as
toddlers or adolescents. Sometimes, surgery (called a
spinal fusion) is done to correct the spinal deformity in
children who are done growing and whose respiratory
systems can tolerate sedation with anesthesia.

39. Outlook
 Scientists who are researching SMA have made
dramatic breakthroughs in the past few years, including
identifying the genes and the protein associated with the
disorder.
 Research is now focused on finding drugs and other
therapies that can help to keep motor neurons
functioning as long as possible, enhance muscle tone
and function, and even modify gene function. Many
scientists are optimistic that ongoing research will lead to
better treatment of SMA.

40. My References
Web references
1. http://www.ninds.nih.gov/news_and_events/news_articles/sensory-
motor_synapses_lost_in_SMA.htm
2. http://en.wikipedia.org/wiki/Spinal_muscular_atrophy
3. http://www.fsma.org/
4. http://healthfinder.gov/FindServices/Organizations/Organization/HR2292/families-of-spinal-
muscular-atrophy
5. http://en.wikibooks.org/wiki/Handbook_of_Genetic_Counseling/Spinal_Muscular_Atrophy_(SMA1
)
Guidelines/books
1. Guide to the Evaluation and Management of Patients with Neuromuscular Disease by Dr John
Bach (2004)
2. Facts about Spinal Muscular Atrophy. Muscular Dystrophy Association
3. Handbook of Genetic Counseling

42. Thank you!!