Approach to floppy child/ LMN Flashcards
What are fasciculations?
Spontaneous and involuntary contractions
What is hypotonia?
Decreased tone separated into central and peripheral causes of hypotonia
What are the central causes of hypotonia?
- Disorder of the CNS
- birth asphyxia, mental retardation - Down’s syndrome
- Metabolic disorders
- rickets
- hypothyroidism - Connective tissue disorders
- marfans syndrome
- osteogenesis imperfecta
What are the peripheral causes of hypotonia?
- Anterior horn cell
- infantile spinal muscle atrophy
- poliomyelitis - Neuropathies(nerve roots)
- Giullian Barre syndrome - Myasthenia gravis (NMJ)
- Muscular dystrophies
- Duchenne’s
- X-linked disorder
How do we clinically asses a child’s tone?
180 degree maneuvre
- Supine(froglike posture usually)
- Head lag
- Pull to sit(a normal baby at 6 months has a rounded back)
- Vertical suspension (the head, arms and legs will usually just dangle like a raggedy doll in these patients)
What must we think is the region of Cayuse if there is developmental delay?
Central lesion
What should we think of if a child has brisk deep tenons and truncal hypotonia?
- Immediately think of hypotonic CP
If the child presents with rickets and acidosis what should we think of?
Endocrine or metabolic cause for the hypotonia
What other clinical signs can children with hypotonia present with?
- Facial muscle movement
- Ocular muscle movement
- Stiff joints-which is common in congenital muscular dystrophy and congenital myotonic dystrophy
- Contractures
- Sucking and swallowing difficulties
What are the anterior horn cell causes?
- Infantile spine muscular atrophy
2. Poliomyelitis
What is infantile spinal muscular atrophy?
- the most common neuro muscular disorder of childhood
- affects the legs more than the arms
- they present with facial weakness 50% of the time and fasciciulations of the tongue
What are the different types of SMA?
- Type 1-most severe and occurs in the first couple of weeks from birth. Mom notices that baby is becoming progressively weaker. They never get to sit
- Type 2-moderate(they never stand)
- Type 3-mild(they can stand alone)
What is SMA Type 1 and how does it present?
—presents in first weeks of life
- presents with generalised weakness,wasting and poor head control
- poor sucking and swallowing because of bulbar weakness
- sweating palms and soles of feet
What in the chest is affected by the child with Type 1 SMA?
- they present with recurrent respiratory infections
- intercostal muscles are affected causing breathing difficulties
- Chest is bell-shaped
What is type 2 SMA?
This type of SMA is moderately severe and occurs in the first months of life
- it commonly involves the respiratory system
- the children present with reduced but not absent reflexes
What is type 3 SMA?
The mildest form of SMA
- the child usually has normal milestones
- the proximal muscle weakness usually presents similarly to Duchenne’s muscle dystrophy
- they usually walk flat footed and the foot is exerted
- they usually have fasciculations of the fingers(micromyoclonus)
- the prognosis is usually good and the tendon reflexes are initially normal
What special investigations do we do in children with spinal muscle atrophy?
- Ultrasound of the muscles shows muscle atrophy and echo
- Muscle enzymes(CPK) are usually normal
- Electromyography- there is neurogenic atrophy and fibrillation potentials and large polyphasic potentials at rest
- Muscle biopsy- there are strophic type 1 and 2 muscle fibres
Is SMA usually autosomal dominant or recessive?
- usually autosomal recessive
- gene SMN is usually translocated to chromosome 5
What management do we do for these patients?
We give them supportive treatment to treat the resp infections and physio
What is poliomyelitis?
- it a condition caused by enterovirus affecting the anterior horn cells
- it is usually preceded by mild GIT symptoms like nausea and vomiting and then develops into fever, headache, pain in the neck, back and limbs and muscle spasms
When do the muscle spasms present in patients with poliomyelitis?
Usually a week or two after the virus enters the gastro-intestinal tract
What are the associated clinical manifestations of poliomyelitis?
- Respiratory depression
- Bulbar involvement affecting swallowing and feeding
- There is often total flaccid quadriplegia (floppy baby syndrome)
What special investigations do we usually do in these patients?
- Electromyography- evidence of denervation
- CSF-usually protein is elevated and there are increased leucocytes
- Culture of the blood or CSF usually confirms diagnosis
How do we manage polio?
- We can prevent it by immunizations
2. Supportive treatment-oxygen etc.