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
Early Infancy Pompe Disease Presentation (9)
- Hypotonia
- Poor feeding
- Poor weight gain
- Poor tone “floppiness”
- Head lag
- Respiratory difficulties
- Enlarged heart
- Enlarged tongue
- Most die within first year of life – cardiac/respiratory complications
Pompe disease clinical presentation and progression (3)
- Musculoskeletal – profound and rapidly progressive muscle weakness
- Cardiac – marked cardiomegaly/cardiomyopathy
- Respiratory – progression to respiratory insufficiency
UMN neuro manifestations (4)
- Hypotonia initially that may later present with fisting of the hands, scissoring, seizures
- May later develop into spasticity and increased tone
- The deep tendon reflexes may be brisk or easily elicited
- Serum muscle enzymes, EMG, nerve conduction and muscle biopsy all normal
Neuromuscular manifestations (3)
- May have more facial expression
- Deep tendon reflexes difficult to elicit or absent in many neuromuscular lesions
- Loss of tone or strength may signify a progressive condition rather than a static problem; progressively loses tone and strength
Prader-Willi Syndrome Etiology (3)
- Chromosome 15 deletion (paternal) or disomy (maternal)
- Methylation analysis >99% detected
- FISH only identifies deletion
Prader Willi Syndrome Presentation in Infancy (7)
- Hypotonia
- Weak cry
- Poor feeding
- Small penis
- Poor growth
- Almond shaped eyes
- Down-turned mouth & thin upper lip
Prader Willi Syndrome Disease Progression (5)
- 2 years of age – develop hyperphagia
- Overweight
- Problems related to obesity
- Behavioral
- Mild to moderate intellectual impairment
Assessing hypotonia evaluation and differential diagnosis (2)
- Complete history and physical exam
2. Age-appropriate cognitive skills should be assessed
Hypotonia clues to help with differential diagnosis (9)
- Facies of Trisomy 21
- Poor feeding, hypotonia, small male genitalia think Prader-Willi Syndrome
- A high-arched palate is often noted in infants with neuromuscular disorders
- Large tongue may be seen in storage disorders (Pompe)
- Tongue fasciculation suggests anterior horn cell involvement
- Neurogenic disorders are associated with a higher incidence of other congenital anomalies
- Myopathic features are less likely to be associated with other defects
- Rapid onset with constipation may indicate botulism
- IEM must be on your list with hypotonia
Hypotonia laboratory work up (7)
- Sepsis has to be ruled out
* Electrolytes, (anion gap- elevated in IEM), LFTs, pH, ammonia levels, organic acids, urine for ketones, spinal fluid for WBC (infection) or protein (immune, storage diseases) may be helpful - Magnesium levels
- Serum creatine phosphokinase (CPK)
* Screen for muscle fiber necrosis
* History suggests degenerative condition, or exam leads to Neuromuscular pathway
* CPK is 10-100 times higher than normal in muscular dystrophy - Consider EMG
- IM Neostigmine test (to confirm myasthenia gravis)
- Muscle biopsy (for neuromuscular disorders)
- Brain MRI
* Exam suggest upper motor neuron (hypotonia with active DTR and ankle clonus)
Things to remember with hypotonia (3)
- Appropriate and cost effective use of lab tests to establish a specific etiologic diagnosis is always desirable
- The history and physical assessment will point out the possible etiology and the indications for diagnostic tests
- Etiologic diagnosis is related to the nervous system level of the lesion
Hypotonia Management (10)
- Depends on diagnosis
- Respiratory support
- Feeding support
- Comfort care if appropriate (Werdnig-Hoffman anterior cell disease –rapidly degenerative, terminal condition)
- Education
- Early intervention
- Physical and Occupational therapy
- Genetics
- Counseling
- Neurology
Hypotonia take home (7)
- Infants with hypotonia pose a challenge
- Key distinction is to determine low tone with or without muscle weakness
- Weak infants are always hypotonic – but hypotonia can be present with normal strength!
- ‘Benign congenital hypotonia’ is a diagnosis of exclusion
- A detailed feeding history from birth may provide valuable diagnostic clues
- The HISTORY may narrow the possibilities significantly
- Pregnancy, delivery, postnatal, infection, family history, consanguinity, feeding issues/special diets?
Infantile Spasms (West Syndrome) Clinical Presentations (6)
Age-related seizure syndrome with typical movements of:
- flexion contraction of the trunk with the head bowed and sudden raising of the arms, and cry
- Sudden jerk followed by stiffening
- “Jack knife seizures”
- Most commonly occur just after waking
- Occur several times in succession in a series – lasts only a second but occurs in a series
- Often mistaken for colic – but colic does NOT occur in a series
Infantile spasms onset and resolution
Onset: 3mo – 2y of age
Resolution: 4y of age
West syndrome clinical triad (4)
- Infantile spasms
- Hypsarrhythmia EEG
- Mental retartdation
- 60% have a ‘brain injury’ before the seizures occur but others have no injury or family history
Infantile Spasms Differential Diagnosis
- Birth trauma
- Congenital infections
- Benign myoclonus of infancy
- Colic
- Sepsis
- Breath-holding spells (apnea)
- Sandifer syndrome
- Infantile shuddering
- Electrolyte imbalance
- Hypoglycemia
- Tuberous Sclerosis – common cause of IS • Drug withdrawal
- Ohtahara syndrome
* Infants with abnormal neurologic exam and structural brain abnormalities
* Burst-suppression EEG pattern
* Poor developmental prognosis
* Devastating disorder
Infantile Spasms Work Up (2)
- May get a full sepsis work up with CSF and MRI
- EEG to confirm diagnosis
* Unusual pattern at rest – hypsarrhythmia – chaotic, high voltage pattern of activity
Infantile Spasms Tx (3)
- Steroid therapy
- Anti-seizure medications
- Ketogenic diet? (low carb, high protein and fat-90%)
Infantile Spasms Prognosis (3)
- Most children are developmentally delayed
- If normal development prior to start of IS may have normal functioning
- Some develop epilepsy later in life
Sacral Dimples and Occult Spinal Dysraphism (5)
- Skin dimples over the spine commonly referred to as sacral dimples are common minor congenital anomalies, estimated to occur in 3-8% of children. When a clinician sees a skin dimple, the possibility of occult spinal dysraphism (OSD) usually crosses the mind.
- OSD is a wide-range of skin-colored spinal column and neuraxis abnormalities that are caused by abnormal neurolation.
- OSD lesions include dermal sinuses, tethered cord, lipomyelomeningocoele, and diastematomyelia.
- Lesions that are greater than 2.5mm above the anus indicate a need for further evaluation
- OSD can present with a variety of abnormalities, but is also frequently asymptomatic and can present at any age. Skin abnormalities accompany 50-80% of OSD
OSD Clinical Presentation (5) and Prognosis (2)
Prognosis:
- OSD is less obvious than open neural tube defect
- Not identified prenatally
Presentation: Impairments progress overtime in these closed defects 1. Paresis 2. Spasticity 3. Sensory disturbance 4. Bowel and bladder dysfunction 5. Deformity
Sacral Dimples: High-Risk Features (7)
- Multiple dimples
- Dimple diameter larger than 5mm
- Location greater than 2.5mm above the anal verge (gluteal creases)
- Association of a dimple with other cutaneous markings
- The end is NOT visualized
- THESE ABOVE NEED FURTHER WORK-UP
- Work-Up is NOT NEEDED for solitary sacrococcygeal dimples located entirely within the gluteal fold with intact skin visible- Normal Anatomic Variant!
OSD Summary (4)
- Spinal skin dimples and cutaneous lesions are associated with OSD/closed neural tube defects
- The presence of more than 1 skin dimple anywhere along the neural axis is an indicator of possible OSD and needs further evaluation
- The neurologic deficits associated with OSD progressive are often not detected until permanent dysfunction
- Early neurosurgical intervention is best to halt or prevent progression of neurological deficits due to spinal cord tethering
OSD Take Home (6)
- Early Diagnosis = optimal outcome
* Early diagnosis of OSD comes from identification of spinal skin dimples!!
* Recognition of lesions is important to reduce risk of neurologic, urologic and ortho dysfunction
TURN THE BABY OVER
- Dimples; Identify dimple location and number present *
- Abnormal Hair growth
- Asymmetric gluteal creases
- Pits, sinuses, hemangiomas
- Skin tags; MAY all be associated with OSD – so image and refer