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Internal Medicine

Foetal alcohol spectrum disorders (FASDs)

Spectrum of conditions that can occur in a person whose mother drank alcohol during pregnancy.

Introduction

Fetal alcohol syndrome, or FAS, occurs because of maternal use of alcohol during pregnancy.

Spectrum of conditions that can occur in a person whose mother drank alcohol during pregnancy.

  • M/C cause of intellectual disability in US

Foetal alcohol spectrum disorders (FASDs):

  • Fetal alcohol syndrome (FAS)
  • Partial fetal alcohol syndrome (pFAS)
  • Alcohol-related neurodevelopmental disorder (ARND)
  • Alcohol-related birth defects (ARBD)

Clinical features

Growth deficiency

4-Digit Diagnostic Code:
  • Severe: Height and weight at or below the 3rd percentile.
  • Moderate: Either height or weight at or below the 3rd percentile, but not both.
  • Mild: Either height or weight or both between the 3rd and 10th percentiles.
  • None: Height and weight both above the 10th percentile.

Three FAS facial features:

  • Smooth philtrum: The divot or groove between the nose and upper lip flattens with increased prenatal alcohol exposure
  • Thin vermilion: The upper lip thins with increased prenatal alcohol exposure
  • Small palpebral fissures: Eye width decreases with increased prenatal alcohol exposure
photo_of_baby_with_fas
Baby with fetal alcohol syndrome. | Teresa Kellerman – http://www.come-over.to/FAS/fasbabyface.jpg, CC BY-SA 3.0, https://commons.wikimedia.org/w/index.php?curid=4847497

CNS damage

4-Digit Diagnostic Code:
  • Definite: Structural/neurological impairments for FAS/static encephalopathy.
  • Probable: Significant dysfunction of 2 SD or worse in ≥ 3 functional domains.
  • Possible: Mild-moderate dysfunction of 2 SD or worse in 1 or 2 functional domains or by judgment of the clinical evaluation team that CNS damage cannot be dismissed.
  • Unlikely: No evidence of CNS damage.

Diagnosis

Fetal alcohol syndrome (FAS) diagnostic criteria

  • Growth deficiency: Prenatal/postnatal height/weight (or both) ≤ 10th percentile
  • FAS facial features: All 3 FAS facial features present
  • CNS damage: Clinically significant structural neurological, or functional impairment
  • Prenatal alcohol exposure: Confirmed/unknown prenatal alcohol exposure

Partial fetal alcohol syndrome (pFAS) diagnostic criteria

  • Growth deficiency: Growth/height range from normal to deficient
  • FAS facial features: 2-3 FAS facial features present
  • CNS damage: Clinically significant structural, neurological, or functional impairment in ≥ 3 of the Ten Brain Domains
  • Prenatal alcohol exposure: Confirmed prenatal alcohol exposure

Alcohol-related neurodevelopmental disorder (ARND) or static encephalopathy diagnostic criteria:

  • Growth deficiency: Growth/height range from normal to minimally deficient
  • FAS facial features: Minimal or no FAS facial features present
  • CNS damage: Clinically significant structural, neurological, or functional impairment in ≥ 3 of the Ten Brain Domains
  • Prenatal alcohol exposure: Confirmed prenatal alcohol exposure

Clinical diagnosis

Ten Brain Domains:
  • Achievement, adaptive behavior, attention, cognition, executive functioning, language, memory, motor skills, multisensory integration or soft neurological problems, social communication

Exposure confirmation “4-Digit Diagnostic Code”

  • High risk: Confirmed use of alcohol during pregnancy known to be at high blood alcohol levels (100 mg/dL or greater) delivered at least weekly in early pregnancy.
  • Some risk: Confirmed use of alcohol during pregnancy with use less than High Risk or unknown usage patterns.
  • Unknown risk: Unknown use of alcohol during pregnancy.
  • No risk: Confirmed absence of prenatal alcohol exposure.

Differential diagnosis:

9 syndromes that have overlapping features with FAS (CDC. However, none of these syndromes include all three FAS facial features, and none are the result of prenatal alcohol exposure:
  • Aarskog syndrome
  • Williams syndrome
  • Noonan syndrome
  • Dubowitz syndrome
  • Brachman-DeLange syndrome
  • Toluene syndrome
  • Fetal hydantoin syndrome
  • Fetal valproate syndrome
  • Maternal PKU fetal effects

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