Fetal Alcohol Spectrum Disorders FASD Diagnosis

Fetal alcohol spectrum disorder (FASD) is sometimes termed as a hidden disability as its symptoms often remain under-diagnosed in many children until they enter adolescence or even adulthood. It is often recognized in school-going children suffering from attention deficit disorder (ADD), attention deficit hyperactivity disorder (ADHD), or learning difficulties.

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FASD mainly occurs in the fetus of pregnant women who had consumed alcohol during their maternity period. Since the diagnosis of FASD involves no specific medical tests (like blood test), the effects of the syndrome are hard to detect.

Successful early diagnosis helps to lower the severity of the disorder and prevents the pathogenesis of secondary conditions. It allows the mother to receive proper counseling to prevent her future children from being affected and also, siblings that have remained undiagnosed may receive appropriate treatment.

FASD diagnostic guidelines

As FASD has a complex set of symptoms, its diagnosis requires a multidisciplinary approach for which a set of guidelines are formulated.

The guidelines relate to six aspects of the diagnostic process.

  1. Screening and referral.
  2. Physical examination and differential diagnosis.
  3. Neurobehavioral assessment.
  4. Treatment and follow-up.
  5. Maternal alcohol history during pregnancy.
  6. Diagnostic criteria for FAS, partial FAS, and alcohol-related neurodevelopmental disorder.

The assessment process needs to be carried out by a diagnostic team comprising of

  • A coordinator—nurse or social worker
  • Physician trained in diagnosis of FASD
  • Psychologist
  • Occupational therapist
  • Speech-language therapist.

Diagnostic process

1.Screening and referral

Screening for alcohol usage is conducted for all post-partum and pregnant women using validated tools like TWEAK, T-ACE, CAGE, and SMAST. Counseling is given to women who are at risk of heavy usage of alcohol.

The following identified persons are sent for referral:

  • Those having facial abnormalities pertaining to short palpebral fissures (small space between the two open eyelids), smooth or flattened philtrum, and thin vermilion border.
  • Those displaying one or more behavioral or learning difficulties.
  • Those with central nervous system or growth deficits.

2.Physical examination and differential diagnosis

The general neurologic and physical examination involves suitable measurements of head and growth. Additional symptoms to look for are characteristic facial and physical features and anomalies such as congenital health defects, cleft palate, high arched palate, hypertelorism, abnormal palmar creases, micrognathia, abnormal hair patterning, and skin lesions. These are required to eliminate multi-factorial disorders that imitate the features of partial FAS or FAS.

The main purpose of dysmorphology assessment is to identify the features associated with prenatal alcohol exposure as well as dysmorphic features in children. Sometimes, children having prenatal alcohol exposure might present other comorbid symptoms too.

Growth

Deficiency is detected by monitoring the child growth. The presence of prenatal and postnatal growth deficiencies is determined as a measurement of height or weight that is at or below 1.5 standard deviation of the 10th percentile with suitable standards.

Facial features

  1. Following are the three characteristic facial features used to differentiate an individual with or without FAS:
  • Small palpebral fissures at or below 2nd standard deviations of the 3rd percentile.
  • Flattened or smooth philtrum is measured using lip-philtrum guide.
  • Upper lip with thin vermilion border is measured using lip-philtrum guide.
  1. Relative physical features like short-upturned nose and epicanthic folds should be recorded.
  2. Measurement of facial features should be performed in all different age groups. In patients with changing facial features, the diagnosis should be on one point where the feature is expressed strongly.

3.  Neurobehavioral assessment

  • The factors to be examined include: hard and soft signs of neurological abnormalities, structure of brain, memory, cognitive assessment (IQ test), academic achievement, ADHD (attention-deficit/hyperactivity disorder), executive functions, abstract reasoning, social communication, adaptive behavior, and social skills.
  • The examination should include primary and complicated tasks and these tasks should be compared in all areas, as suitable.
  • Even if the areas are independent entities, they should be examined.

4.  4-Digit diagnostic code

4-digit diagnostic code is introduced to identify, examine, measure, and describe objectively the brain damage, alcohol exposure, facial feature, and growth. For every examination, the 4-digit diagnostic code must be recorded, because it may be useful for future research purposes and observation. It has been identified that during neuropsychological data comparison, the neurobehavioral outcomes in ARND and FAS diagnostic groups can overlap.

The following diagnostic protocols are applicable only for FAS, pFAS, and ARN:

FAS: Evidence of impaired pre- and post-natal growth should be present at least in one of the following:

Height and weight of birth for gestational age should be at or lower than 10th percentile; height or weight for age is also to be at or lower than 10th percentile; and weight-to-height ratio should be disproportionately low.

pFAS and ARND: The diagnostic criteria for pFAS and ARND are the same.

  • Presentation with facial anomaly can be simultaneously performed at any ages, which are short length of palpebral fissure, smooth philtrum, and thin upper lip.
  • Confirmed prenatal exposure to alcohol.

Reviewed by Afsaneh Khetrapal Bsc (Hons)

Further Reading

Further Reading

Last Updated: Jan 19, 2018

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