Neonatal hypotoni ”Floppy infant syndrome”

Thomas Sejersen, Neuropediatriken, Astrid Lindgrens Barnsjukhus, Karolinska Universitetssjukhuset

-illustreras ofta med trasdocka:

V Dubowitz, ”The floppy infant”, Mac Keith Press, 1991

”Floppy infant syndome”:

A condition of marked muscle relaxation in a baby so that when supported face down the baby droops over the hand like an inverted "U”

Incidence: ?/1000

Tecken till Hypotoni

 Ø Poor  ability  to  cough  and  clear  airway  secre4ons.  

Ø Poor  swallowing  ability  Ø Crying  character  [weak,  low  pitched]  Ø Paradoxical  breathing  pa=ern.  Intercostal  muscles  paralyzed  with  intact  diaphragm.  

V Dubowitz, ”The floppy infant”, Mac Keith Press, 1991

Normal Fullterm Normal Preterm Floppy infant

-skiljer sig från ”omogen” motorik hos prematur:

Ådén & Sejersen, Handbook of Management of Neurological Disorders in the First Year of Life (Ed C Kennedy), Mac Keith Press, 2011. Ill: R Lagercrantz

Normal nyfödd

Ådén & Sejersen, Handbook of Management of Neurological Disorders in the First Year of Life (Ed C Kennedy), Mac Keith Press, 2011. Ill: R Lagercrantz

Floppy infant, -typiska tecken:

Bodensteiner, Semin Pediatr Neurol 15:10-20, 2008

”Pull to sit” Scarf sign

Axillarhäng Hängande med bukstöd

Floppy infant, -typiska tecken

”Floppy infant syndome”, -tidiga ”varningssignaler”:

•  Polyhydramnios

•  Minskade fosterrörelser

•  Komplikationer vid förlossning

Floppy infant: Vad är orsaken? (>200 tillstånd) Diagnostik-utredning?

Floppy infant: Vad är orsaken? Steg 1: Central eller perifer orsak?

Anatomisk approach till muskulär hypotoni Central orsak

Perifer orsak •  Framhorn •  Perifer motornerv •  Motorändplatta •  Muskel

Anatomisk nivå - orsak:

Bodensteiner, Semin Pediatr Neurol 15:10-20, 2008

Central eller perifer orsak??

Central orsak •  Sänkt medvetande •  (Utan svaghet) •  Extremitetsreflexer

ofta stegrade •  Primoreflexer sänkta

Perifer orsak •  Normalt medvetande •  Svaghet •  Frånvaro av

extremitetsreflexer

Central orsak: Hypoxic ischemic encephalopathy HIE* Developmental disturbance*(Prader-Willi, neuronal

migration disturbance, Down´s syndrome, ) Intracranial hemorrhage Infection (congenital or aquired) Metabolic encephalopathies Drug effects Endocrine encephalopathies Trauma (spinal cord)

* Most common causes

Central orsak:

The Floppy Infant: Evaluation of Hypotonia. Dawn E. Peredo and Mark C. Hannibal Pediatrics in Review 2009;30

Benign Kongenital Hypotoni

Ø The term benign congenital hypotonia is retrospective and refers to infants who are hypotonic at birth or shortly thereafter and later have normal tone.

Ø It encompasses many different pathological processes that affect the brain, the motor unit, or both.

Ø Most affected children have cerebral hypotonia. Ø An increased incidence of mental retardation,

learning disabilities, and other sequalae of cerebral abnormality are evident later in life, despite the recovery of normal muscle tone.

Utredning central orsak:

•  B-glukos, elektrolyter, blodgas, B-status/diff, s-bilirubin, screen för sepsis inkl LP

•  EEG/aEEG •  Ultraljud/CT/MR hjärna •  Metabol utredning, TORCH •  Karyotyp/Array CGH om dysmorfa drag •  Genetisk analys Prader-Willi syndrom eller

annan misstänkt hereditär sjukdom/syndrom (”New generation sequencing”)

Tecken MOTOR UNIT Hypotoni: Disorders of the motor unit are not associated with

malformations of other organs except for joint deformities and the mal development of bone structures.

Ø Absent or Depressed reflexes Ø Intact brain function Ø Muscle atrophy Ø Fasciculations Ø Failure of movement through postural reflexes Ø No extra-cranial organ malformations

Floppy infant, -perifer orsak:

Drabba motorisk enhet: motor neuron och dess innerverade muskler

Perifer orsak hypotoni Neuromuskulära sjukdomar:

•  Motor neuron

- SMA, polio •  Axon

- Guillain-Barré, HMSN •  Neuromuscular junction

- Myastenia •  Muscle fiber

- Myotubular myopathy

Avsaknad av smn-1 vid SMA leder till förlust/död av motorneuron

Smn-1: •  uttrycks specifikt i

motorneuron •  Medverkar i bildning

spliceasomer •  Smn-2 kan delvis

kompensera förlust smn-1

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