spinal muscular atrophy (sma)

8/14/2019 Spinal Muscular Atrophy (SMA)

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11/1/13


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4 month old female presenting with had decreasedstrength and movement.

Mom notes that her symptoms began ~2 months prior.At that point, mom was concerned that she did notappear to have similar strength to her older brother hadwhen he was two months old.

She was not able to lift her head above 90 degrees. Additionally, dad noted that she had decrease

movement of bilateral upper and lower extremities. She would only move her hands and arms from side toside, little movement of her legs.

**However, dad noted that when she was in thebathtub she would move her limbs. (decreased gravity)


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Due to these concerns she was seen by herpediatrician and told that it her tone was

within normal limits.


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Her weakness continued. At her 4 month well child, her pediatrician

was concerned about her hypotonia. At thatvisit, she was also dropping off the growthcurve.

ROS: Over past couple of weeks she has beenchoking and gaging with feeds, but nevervomit. Weak cry. No fevers, chills, illnesses orother concerns


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PAST MEDICAL HISTORY: Birth History: Born full term via NSVD, scheduled

induction. No complications with pregnancy or delivery.Mild jaundice when born, but no use of bili lights.

Occasional "congestions". Regularly breastfed, but hasbeen given formula for last week and a half afterrecommendation of pediatrician noted weight percentiledropping.

PAST SURGICAL HISTORY: None

MEDICATIONS TAKEN REGULARLY: None

ALLERGIES: NKDA


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SOCIAL HISTORY: Lives at home with mom,dad, older brother, and pet dog. She does not

attend daycare. Older brother is sick with URIsymptoms.

FAMILY HISTORY:

Father with DM1 diagnosed as teen.

Eczema in older brother.


7/21

Vital Signs: 5.98 kg, height is 63 cm, OFC of 41.5 cm General: alert, smiling patient who has definite weakness

with minimal movement of her body, arms, or legs.HEENT: Her pupils are equal, round, and reactive to light.

Extraocular muscles are intact. I am unable to view herfundi. Tongue fasiculations. No dysmorphic features Neck: Full range of motion with no masses, but poor neck

control. Respiratory: Clear to auscultation, though she does have

some increased work of breathing. Pectus excavatum. Shedoes have a bell-shaped chest with some increased workof breathing.

Cardiovascular: Regular rate and rhythm withoutmurmur.

Abdomen: Supple and non-tender with no organomegaly.


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Neuro:

Minimal movement of her arms and legs.

Cognitively, she is smiling, she is interactive.

Cranial nerves II through XII with no facial diplegia.

Her tone is decreased both centrally and peripherally.

Her reflexes are very minimal, both in her arms and

legs. Her strength shows significant weakness in arms and

legs and in the core of the body.

Sensory examination seems normal.


9/21

4 month old girl who presents with hypotoniax2 months and failure to thrive.


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ID: Sepsis Meningitis Encephalitis Neonatal poliomyelitis

TORCH InfectionsGenetic: Down syndrome Prader-Willi syndrome Cerebral dysgenesis Peroxisomal disorders:

cerebrohepatorenal syndrome(Zellweger syndrome) akaleukodystrophy

Endocrine: Hypothyroidism

Metabolic disorders: Disorders of creatine

metabolism Mitochondrial myopathies Cytochrome-c oxidase deficiency

Disorders of glycogenmetabolism Acid maltase deficiency Severe neonatal

phosphofructokinase deficiency Severe neonatal phosphorylase

deficiency

Other: Drug intoxication Botulism HIE Intracranial hemorrhage


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NEURO

Anterior horn cell (lower motorneuron) Spinal muscular atrophy Glycogen storage disease

type II (Pompesdisease) Hypoxic-ischemic injury Neonatal poliomyelitis

Level of peripheral nerve CIDP Neuroaxonal dystrophy (rare) Mitochondrial disorders Lysosomal (Krabbesdisease)

Level of neuromuscular junction Myasthenia

Hypermagnesemia andaminoglycosides Infant botulism

Level of the muscle Muscular dystrophy

Metabolic myopathies:mitochondrial, glycogendisorder, and lipid disorders

Congenital myopathies:nemaline (rod body),myotubular (centronuclear)


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SMAs are a group of diseases characterized by aprogressive loss of spinal anterior horn cellsleading to muscular denervationatrophy andweakness

Second most common hereditary neuromusculardisease, with a carrier frequency of one in 50 to one in80 and an incidence of one in 10,000 to one in 25,000

The most common forms of SMA are transmitted byautosomal recessive inheritance, with the gene defectlocalized to the motor neuron survival gene (SMNgene) on chromosome 5q.

Rare X-linked and autosomal dominant forms havebeen recognized


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SMA type 1 (Werdnig-Hoffman disease), is mostcommonly described as the acute infantile form ofSMA

Symptoms typically recognized within the first sixmonths of life

Severe, progressive muscle weakness and flaccid orreduced muscle tone

Bulbar dysfunction includes poor suck ability, reducedswallowing, and respiratory failure.

Patients have no involvement of the extraocularmuscles, and facial weakness is often minimal orabsent.

Patients rarely develop the ability to sit unassistedand usually die by two years of age


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SMA type 1 appear normal on first glancebecause extraocular movements are spared

and muscles of facial expression relatively so BUT as weakness develops, fasciculations of

the tongue and fingers may be noted.

As things progressfeeding and swallowingare compromised

Treatment of SMA type 1 is supportive


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Diaphragm IS the primary muscle of breathing--diaphragm function improved when flat or inTrendelenburg

Intercostals are weak and ineffective Chest wall compliance is increasedchest wall

shape canges into bell shaped chest Respitary weaknessHypoventilation

**Oxygen therapy does not addresshypoventilation Non-invasive positive pressure ventilation

(NIPPV) BiPAP


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SMA type 2 has intermediate severit Patients may be able to sit unassisted, are

generally unable to stand or walk withoutassistance, but may survive well intoadolescence or young adulthood

SMA type 3, typically symptomatic after 18months of age and follows a slower diseaseprogression, with survival into adulthood


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Dr. Swaboda, department of neurology


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Leyenaar J. A schematic approach to hypotonia in infancy.Paediatr Child Health. 2005 September; 10(7): 397400

The Floppy Infant: Evaluation of Hypotonia. Pediatr. Rev.2009; 30:e66-e76

Evaluation and Differential Diagnosis of the HypotonicInfant. PEDIATRICS IN REVIEW Vol. 6 No. 8 February 1,1985: 237 -243

Spinal muscular atrophy: survival pattern and functionalstatus. Pediatrics. 2004 Nov;114(5):e548-53. Epub 2004

Oct 18. Spinal muscular atrophy type I: Do the benefits ofventilation compensate for its burdens? J Paediatr ChildHealth. 2013 Oct;49(10):807-12.

spinal muscular atrophy (sma)

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