II. Signs: Perform complete physical examination

  1. Infant with decreased Muscle tone
  2. Exam distinguishes site of disorder
    1. Upper Motor Neuron Lesion
    2. Lower Motor Neuron Lesion

IV. Differential Diagnosis: Lower Motor Neuron Causes

  1. Brainstem or spine
    1. Spinal muscular atrophy (Anterior Horn Cell Disorder)
    2. Acute Flaccid Paralysis
    3. Infection
      1. Poliomyelitis
      2. Coxsackie Virus
  2. Neuromuscular Junction
    1. Congenital Myasthenia Gravis
    2. Lambert-Eaton Myasthenic Syndrome
    3. Guillain Barre Syndrome
    4. Botulism
  3. Muscle
    1. Muscular Dystrophy
    2. Congenital Myopathy
    3. Inflammatory Myopathy
  4. Other
    1. Tick Paralysis
    2. Benign Congenital Hypotonia

V. Imaging

  1. Head MRI (or consider Head CT if MRI not available)

VI. Diagnostic Studies

VIII. Labs: Test as indicated

  1. Toxicology screen
  2. Serum Ammonia and Venous pH
    1. Serum Amino Acids
    2. Urine Amino Acids and organic acid
  3. Karyotype
  4. TORCH Virus Screening

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Related Studies

Ontology: Floppy infant syndrome (C0270971)

Concepts Disease or Syndrome (T047) , Congenital Abnormality (T019)
ICD10 P94.2
SnomedCT 206587003, 193217002, 33010005, 205294008
Italian Ipotonia del lattante, Ipotonia neonatale congenita
Japanese 筋緊張低下児, 先天性筋緊張低下児, センテンセイキンキンチョウテイカジ, キンキンチョウテイカジ
English 'Floppy' infants, Floppy infant syndrome, Floppy baby syndrome, unspecified, floppy infant syndrome, floppy baby, hypotonia congenital, congenital hypotonia, floppy infants, babies floppy, infant floppy, floppy infant, neonatal hypotonia, congenital hypotonia (diagnosis), Congenital floppy infant, Hypotonia, congenital, Congenital hypotonia (disorder), Congenital hypotonia, Floppy baby, Floppy infant, Floppy infant syndrome (disorder), baby; floppy, floppy baby syndrome, floppy baby; syndrome, floppy; syndrome, baby, infant; floppy baby syndrome, syndrome; floppy baby syndrome, syndrome; floppy baby, syndrome; floppy, baby, Congenital hypotonia [Ambiguous]
Spanish síndrome del niño flojo, bebe flácido, Niño hipotónico congénito, Niño hipotónico, síndrome del niño flojo (trastorno), síndrome del lactante hipotónico (trastorno), síndrome del lactante hipotónico
German Angeborene Muskelhypotonie, Floppy infant, kongenitaler Floppy Infant
Czech Vrozený syndrom floppy infant, Floppy baby
Korean 선천 긴장과소
Hungarian Infantilis izomhypotonia, Veleszületett atoniás csecsemő
Dutch baby; slap, floppy; syndroom, infant, infant; floppy infant syndrome, slappe baby; syndroom, syndroom; floppy infant syndrome, syndroom; floppy, infant, syndroom; slappe baby, Congenitale hypotonie, floppy infant, congenitaal, floppy infant
Portuguese Criança hipotónica congénita, Criança hipotónica
French Floppy infant, Hypotonie congénitale majeure