Neuro Flashcards
Hypotonia
“Floppy”
Definition: Simply defined as lower than normal resistance to passive motion across a joint
*Abnormal posture is also suggestive
Hypotonia key components (2)
- Muscle strength is a key component
2. Tone can be used as an indicator of strength in infants who cannot cooperate with resistance testing
Floppiness
A term used to describe babies who have marked muscle hypotonia
hypotonia epidemiology (2)
- Not unusual in newborns
2. Non-neuromuscular causes more common than neuromuscular
hypotonia family hx and genetics (4)
- Genetic abnormalities frequently present after birth, low tone, poor feeder
- Non-response to painful stimuli
- Is this a boy? (Duchenne muscular dystrophy)
- Spontaneous mutation?
Hypotonia patient history (7)
very important to ask these questions!!
- Were there fetal movements (same as previous pregnancies)?
- What happened at the delivery?
- Was there birth trauma?
- Hypoxic-ischemic encephalopathy (HIE)
- What is the gestational age at birth?
- IVH/PVL brain lesions
- Is the infant losing developmental skills- or has not progressed?
Hypotonia noting time of lack/loss of tone (3)
- Rapid onset hypotonia, constipation, poor feeding in infants, think: Infant Botulism (C. botulinum) – a spore-forming organism found in nature
- Ask what they ate – contaminated honey or soil
- Treatment: Botulism Immunoglobulin →full recovery
Hypotonia in newborn period (4)
- Asked to evaluate the “floppy” infant
- Tone related
- Poor feeder
- Lack of movements
Hypotonia after newborn period (3)
- Usually accompanied by a concern about developmental progress
- Lack of meeting milestones
- Most likely the motor development raises a red flag
Hypotonia clinical presentation (5)
- Posture of full abduction and external rotation of the legs as well as a flaccid extension of the arms
- When traction is delivered to the arms, there is prominent head lag
- The presence of a typical ‘myopathic’ facies and lack of facial expression are common
- Low pitched cry or a progressively weaker cry – easily distinguishes from a vigorous cry of a normal infant
- Lack of antigravity movements
Hypotonia physical exam (3)
- In newborns tone measurement is subjective
- Dependent on the experience of the examiner
- Quantification of tone has been problematic?!
maneuvers identified to be useful in the demonstration of tone and the detection of abnormalities of tone (4 maneuvers, 2 info)
- Pull to sit
- Scarf sign
- Shoulder suspension
- Ventral suspension
INFO:
1, Remember – tone is gestational age dependent and you must take into account the State-Of-Alertness of the infant during exam
2. Regularly performing the maneuvers will help develop a sense of what is normal and what is not
Hypotonia neuro level affected… (4)
- The neurological exam correlates the site of the lesion with the level of the nervous system affected (UMN, Spinal cord, Anterior horn cells, peripheral nerve, neuromuscular junction, muscle).
- The neuro exam is most important in determining the etiology of hypotonia in infants.
- Central (60-80% of causes)-(non-neuromuscular)
* Upper motor neurons – brain, brainstem, cervical spinal junction – inputs from the CNS - Peripheral regions (15-30%)-(neuromuscular)
* Lower motor region, anterior horn cells, neuromuscular junction, muscles
Central non-neuromuscular (UMN) hypotonia Causes (7)
- More common than peripheral disorders
- HIE
- Brain insult
- Intracranial hemorrhage
- Chromosomal disorders
- Congenital syndromes
- Inborn errors of metabolism
Peripheral neuromuscular hypotonia Causes (5)
- Abnormalities in the motor unit specifically the anterior horn cell
- Spinal muscular atrophy
- Myasthenia gravis (peripheral nerve)
- Botulism (neuromuscular junction)
- Myopathy (muscle)
Pompe disease epidemiology and etiology (3)
- Rare 1:40,000
- Inherited, fatal disorder if complete deficiency
- Cannot breakdown glycogen d/t lack of acid alpha-glucosidase (GAA) – excessive amounts of lysosomal glycogen accumulates in the body
* Heart and Skeletal Muscle