Approach
Introduction
Diagnosis is based on a thorough history and examination; no specific diagnostic tests confirm the diagnosis of fetal alcohol spectrum disorder (FASD). A number of diagnostic criteria exist.[33][34][35][36][37][38] Although these criteria have some common features, subtle differences in terminology and classification of FASD may confuse clinicians and it should be regarded as an international priority to standardise the diagnostic process.
Diagnosis of children with FASD is crucial for several reasons.
For parents and carers, diagnosis often comes after years of uncertainty and provides relief.[39] It provides an explanation for their child's problems and an opportunity to:
Identify the child's strengths and needs
Adjust their expectations
Promote the child's strengths.
Early diagnosis enables early intervention. There is evidence that early diagnosis decreases the risk of secondary disability in adolescents and adults.[40]
Diagnosis may have practical benefits: for example, entitling carers to a 'disability allowance' or other government financial support, support for medical interventions, provision of supernumerary or remedial teachers in the classroom, and free access to appliances (e.g., hearing aids).
Importantly, recognition of the child with FASD will identify women at risk of harm from alcohol and allow referral and treatment. This in turn may prevent the birth of a subsequent affected child.
History
Maternal history should include questions about alcohol consumption (i.e., amount and frequency currently and during pregnancy), drug and teratogen exposure during pregnancy (including illicit and prescribed drugs to rule out differential diagnoses), and medical conditions. A family history may identify genetic diseases, familial birth defects, or patterns of malformation. Information on gestation, intrauterine growth retardation, birth weight, birth order, and birth defects should also be ascertained.
Average age at diagnosis varies from 3.3 to 10 years.[41][40] Only 7% of affected children are diagnosed at birth, but 63% are diagnosed by 5 years of age.[41] FASD is underdiagnosed in the newborn period, even when physical features are present.[41][42] A barrier to early diagnosis is that the diagnostic criteria for FASD relating to neurodevelopment are difficult to be assess during infancy.[42] Challenges to making the diagnosis in adulthood include difficulties in obtaining reliable documentation of antenatal alcohol exposure and possible attenuation of the characteristic facial features with age.[43]
At presentation, the developmental history of the child should be elicited, including whether developmental milestones were delayed. Specifically, the history may include the following:
Infants: poor feeding, growth retardation, irritability, or developmental delay, including delayed motor milestones or delayed speech and language development
Children: growth retardation, or problems with language, speech, hearing, vision, learning, behaviour, attention, and academic achievement
Adolescents: drug and alcohol abuse, poor educational performance (e.g., poor reports from school, particularly in numeracy and literacy, repeating grades), poor social skills (e.g., isolation, forming poor peer relationships, inappropriate sexual behaviour), or contact with juvenile justice or incarceration.
Symptoms of inattention, hyperactivity, impulsivity, or risk taking may point towards attention-deficit/hyperactivity disorder (ADHD). Mental health disorders may be seen in adolescents. Internalising behaviours include anxiety and depression; externalising behaviours include conduct disorder, oppositional defiant disorder, and ADHD.
Information about siblings is also important, as a significant proportion will be similarly affected.
Physical examination
Confirmation of diagnosis depends on the patient fulfilling specific diagnostic criteria. Several criteria are in use and, although international consensus would be optimal, choice is guided by local practice and clinician preference. The criteria define the specific features of the 4 disorders that make up FASD.
Height, weight, and head circumference should be measured and plotted on growth charts for the relevant population. Cut-off percentiles vary according to the diagnostic criteria used. In most criteria, the cut-off points for children with fetal alcohol syndrome (FAS) are weight and height measurements below the 10th percentile for age and head circumference <3rd percentile (microcephaly).
Characteristic facial dysmorphology includes the following features: short palpebral fissure, thin upper lip or vermillion border (rank 4 or 5 on the lip-philtrum guide), and smooth philtrum (rank 4 or 5 on the lip-philtrum guide). The lip-philtrum guides are 5-point pictorial guides developed at the University of Washington, Seattle and used to assess philtrum smoothness and upper-lip thinness. FAS Diagnostic and Prevention Network: lip-philtrum guides Opens in new window
The face should also be examined for the following features: flat midface, large ears with 'railroad-track' ear abnormality, epicanthic folds, hypertelorism (wide-spaced eyes), ptosis (droopiness of the eyelids), micrognathia (undersized jaw), microphthalmia (small eyes), and cleft lip and/or palate.
The presence of major birth defects, as well as minor anomalies, should be assessed.[33][38]
Cardiac anomalies include:
Atrial septal defects
Ventricular septal defects
Aberrant great vessels
Tetralogy of Fallot
Conotruncal defects.
Musculoskeletal anomalies include:
Hypoplastic nails
Shortened fifth fingers
Radioulnar synostosis
Flexion contractures
Camptodactyly
Clinodactyly of the fifth finger
Pectus excavatum or carinatum
Klippel-Feil syndrome
Hemivertebrae
Scoliosis
Hockey-stick palmar creases.
Renal anomalies include:
Aplastic, dysplastic, or hypoplastic kidneys
Ureteral duplication
Hydronephrosis
Horseshoe kidneys.
Ocular anomalies include:
Strabismus
Retinal vascular anomalies
Refractive problems.
Ear anomalies
Conductive and/or sensorineural hearing loss
Structural ear abnormalities (e.g., 'railroad-track' ear).
A thorough neurological examination should be performed, including power, tone, reflexes, coordination, and cranial nerves. Neurological hard signs (e.g., abnormal reflexes, power, or tone) and soft signs (e.g., discoordination and mirror movements) may be present. Formal age-appropriate audiological and ophthalmological assessments are required in all children.
Assessment of central nervous system dysfunction should also address specific domains of dysfunctions that have been identified in children with FASD, including problems with cognition IQ, executive functioning and abstract reasoning, motor function (delay or deficits), attention and hyperactivity, memory, social skills, sensory issues, speech and language, pragmatic language, academic achievement, internalising and externalising disorders, and other mental health and behavioural disorders.[36][44] The choice of tests used to assess these domains is guided by cultural validity, test availability, patient age, and clinician preference but should include validated tools when available.[36][45][46] A guide to appropriate assessment for neurodevelopmental impairment is provided in several diagnostic guidelines.[36][47] See also: Assessment of learning difficulty and cognitive delay.
Investigations
There is no specific diagnostic tests for FASD and diagnosis is based on a multi-disciplinary assessment. In a child with abnormal facial features, a digital photograph can be used in conjunction with facial diagnostic software to aid confirmation of the diagnosis. FAS photographic diagnostic software assists the clinician to analyse a 2-dimensional facial photograph by enabling accurate measurement of the palpebral fissure length and calculating the percentile value. It also enables calculation of the upper-lip circularity (area) and assignment of severity of upper-lip and philtrum abnormality.[48]
Few other specific investigations are indicated. Rather, investigations should follow identification of abnormal symptoms and clinical signs. For example, an electrocardiogram and echocardiogram should be ordered in a child with a suspected cardiac defect, a magnetic resonance imaging (MRI) or computed tomography scan of the head in a child with microcephaly, an abdominal ultrasound scan in a child with a palpable mass, an electroencephalogram in a child with seizures, a skeletal x-ray in a child with suspected musculoskeletal anomalies. Genetic testing (chromosome microarray) is indicated in all children to exclude genetic diagnoses, as is testing to exclude fragile X as a potential cause of neurodevelopmental impairment. Many clinicians will perform screening tests (e.g., ferritin, thyroid function, serum lead, creatine kinase, and urine metabolic screen) to exclude common treatable causes of developmental disorders.
Antenatal ultrasonography may be considered if there has been heavy alcohol intake during pregnancy, to look for intrauterine growth retardation, poor head growth, and/or specific birth defects.
Emerging evidence suggests that functional MRI, magnetic resonance spectroscopy, and 3-dimensional facial imaging may become valuable diagnostic tools. There is emerging evidence of epigenetic markers of antenatal alcohol exposure in offspring but this is currently a research tool.[49][50]
Referral
Formal assessment by a sub-specialist paediatrician, educational psychologist, neuropsychologist, occupational therapist, speech therapist, physiotherapist, optometrist, and/or audiologist may be appropriate in response to cues from the history or examination. The specific tests used will vary according to the country, population, age of the child, physician and allied health training, and preference.
Referral to a clinical geneticist may be required for confirmation of diagnosis and exclusion of alternative diagnoses. Psychiatric assessment may also be appropriate. Ideally, children suspected of having FASD should be referred to a multidisciplinary 'one stop' diagnostic and assessment clinic such as a child development unit or a specific FASD assessment clinic for children with antenatal alcohol exposure. Most such clinics are located in the US and Canada. Although they are increasingly available internationally, many depend on research funding and may not be sustainable.[44]
Young children with a history of antenatal alcohol exposure but no physical features of FASD require follow-up because associated learning, behavioural, and mental health problems may not become evident until school age.
Barriers to diagnosis
Health professionals may fail to make a diagnosis of FASD for a number of reasons. These include lack of knowledge about the effects on the unborn child of antenatal alcohol exposure and failure to ask about alcohol use during pregnancy and identify 'at-risk' pregnancies.[51][52] Health professionals may also have inadequate knowledge of the diagnostic features and currently used diagnostic criteria and may lack confidence in the management of FASD, including uncertainty about referral processes, diagnostic services, and treatment.[51][52] Reluctance to discuss the diagnosis with parents/carers and fear of stigmatising the child and family may also be deterrents.[51][52]
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