Central Hypotonia ✅ Flashcards
What do you need to distinguish between when assessing hypotonia?
- Central hypotonia
- Generalised hypotonia and weakness
- Peripheral hypotonia
Where does central hypotonia affect?
Predominantly head and trunk
Where does generalised hypotonia and weakness affect?
All aspects
Where does peripheral hypotonia affect?
Predominantly th elimbs
When does moderate to severe central hypotonia tend to be identified?
In the neonatal period
How might moderate to severe central hypotonia present in the neonatal period?
- Respiratory difficulties
- Feeding difficulties
- ‘Floppy baby’
What investigations may be done in an infant with central hypotonia?
- Microbiological tests
- Neuroimaging
- Blood ammonia and lactate levels
- Plasma and urine amino acids and urine organic acids
- Very long chain fatty acids
- Microarray-based comparative genomic hybridisation
When are microbiological tests done in central hypotonia?
If presenting in neonatal period
Why are microbiological tests done in central hypotonia presenting in the neonatal period?
Rule out sepsis
What are blood ammonia and lactate levels done in central hypotonia?
Look for inborn errors of metabolism
Why are plasma and urine amino acids and urine organic acids done in central hypotonia?
Look for organic acidaemias
Why are very long chain fatty acids checked in central hypotonia?
Look for peroxisomal disorders
What specific disorder types should be considered in central hypotonia?
- Aneuploidy
- Single gene disorders
- Metabolic disorders
- Structural disorders
Give an example of an aneuploidy disorder than can cause central hypotonia?
Down’s syndrome,
Give an example of a single gene disorder that can cause central hypotonia?
Prader-Willi syndrome
Give an example of a metabolic disorder that can cause central hypotonia?
Peroxisomal diosrders
Give an example of a structural disorder that can cause central hypotonia?
Structural brain malformations
What causes Down’s syndrome?
Additional copy of chromosome 21
What are the potential mechanisms behind the additional chromosome 21 in Down’s syndrome?
- Non-disjunction (most common)
- Unbalanced translocation
- Mosaicism
What are the clinical features of Down’s syndrome?
- Typical dysmorphic features
- Central hypotonia
- Delay in all developmental milestones
- Initial feeding difficulties
- Associated congenital anomalies, including heart defects
In what % of children with Down’s syndrome are there associated congenital anomalies?
50%
What happens to the hypotonia in a child with Down’s syndrome with age?
In some, disappears as child develops, but many stay ‘floppy’. Studies have shown that infantile floppiness does improve over time, but often remain with some degree of hypotonia
What is the result of continued hypotonia in a child with Down’s syndrome?
Responsible for much of their delay in motor milestones and impaired motor function
Why is the belief that the floppiness of children with Down’s syndrome is responsible for their motor delay disputed?
Recent studies have shown that hypotonia is seen when children and adults with Down’s syndrome are not moving, and therefore it doesn’t actually impair coordinated movement
