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Fetal Alcohol Syndrome

FAS

Fetal alcohol syndrome is a group of defects that occur in a fetus due to high levels of alcohol consumption during pregnancy.


Presentation

The main organ affected in fetal alcohol syndrome is the developing brain which can result in permanent sequalae in the form of mental, psychological and behavioral disturbances [4]. There are an array of defects including poor memory, attention deficit, impulsiveness and poor reasoning. The babies who suffer from fetal alcohol syndrome are more prone to mental health problems even later in life including drug addictions, aggressiveness etc. Alcohol exposure can cause damage to the brain during any period of pregnancy as fetal brain growth occurs throughout pregnancy upto the first 2 years of life.

The presence of facial features in fetal alcohol syndrome indicates significant brain damage; however, brain damage can occur even in the absence of facial features. The facial deformities are caused mainly due to alcohol consumption between 10-20 weeks gestation. 

Facial features include small head circumference (microcephaly), small eyes (small palpebral fissures), low nasal bridge, midface hypoplasia, thin upper lip and indistinct philtrum (the groove between nose and upper lip) [5].

The baby is small for date i.e. has below average weight and height due to growth retardation. The growth can be severely affected when the weight for height is less than 3rd percentile for the age.

The three features that are characteristic of fetal alcohol syndrome are the smooth philtrum, thin vermillon and small palpebral fissures [6].

The risk of neuron damage worsens as the eyes get smaller, lip gets thinner and the philtrum gets flatter. The development of eyeballs and midface occurs in close relation to the development of the brain, therefore in fetal alcohol syndrome, midface and eyeballs are characteristically affected along with brain.

Alcohol acts as a teratogen affecting the developing Central Nervous System (CNS) leading to damage based on the quantity, frequency and the timing of alcohol consumption during pregnancy [7]. Alcohol can cause CNS damage in structural as well as functional areas of brain.

Structural abnormalities include microcephaly (small head circumference of three standard deviation below average) or other abnormalities like agenesis of corpus callosum, cerebellar hypoplasia and hydrocephalus.

Neurological problems might be expressed as hard signs like epilepsy or seizure disorder, or soft signs like impaired fine motor skills, sensory hearing loss, impaired gait, clumsiness and poor hand eye coordination [8].

Functional problems are seen in the form of delays, disabilities and deficits caused as a result of prenatal exposure and not by hereditary causes or post natal insults. Functional problems include learning disabilities, scholastic backwardness, impulsiveness, inattention, poor memory and attention span, poor reasoning and abstract thinking.

Other conditions may commonly co-occur with fetal alcohol syndrome as a result of antenatal exposure of alcohol, however these conditions are considered as alcohol-related congenital defects and are not a part of the diagnostic criteria of Fetal alcohol syndrome. Common associations are:

Developmental Delay
  • We show that developmental ethanol exposure causes reduced viability, developmental delay and reduced adult body size.[ncbi.nlm.nih.gov]
  • Quite the contrary, developmental delay in FAS children seems to be positively moderated by PTB, as being born preterm is cutting short the noxious intrauterine alcohol exposition of the child. Georg Thieme Verlag KG Stuttgart · New York.[ncbi.nlm.nih.gov]
  • Neurologists are frequently called upon to evaluate and recommend treatment for children with developmental delay or neurologic manifestations of FAS.[ncbi.nlm.nih.gov]
  • This article reports a case of a 9-year-old adopted girl with developmental delay, mildly dysmorphic facial features, and behavioral and cognitive abnormalities.[ncbi.nlm.nih.gov]
  • CONCLUSIONS: Findings indicate neuromotor deficits and developmental delay in goal-directed arm movements because of prenatal alcohol exposure.[ncbi.nlm.nih.gov]
Death in Infancy
  • The purposes of this case report are to show an uncommon manifestation of sudden unexpected death in infancy case for the forensic pathologists and to emphasize on the national healthcare problem.[ncbi.nlm.nih.gov]
Corneal Opacity
  • Low-incidence anomalies include corneal opacities (Peters anomaly in one), cataract, tortuosity of retinal vessels, and long eyelashes.[ncbi.nlm.nih.gov]
Manic Behavior
  • We present a case of manic behavior after a closed head injury to the left hemisphere in an adult with preexisting fetal alcohol syndrome.[ncbi.nlm.nih.gov]
Thin Lips
  • Ranks 4 and 5 reflect the thin lip and smooth philtrum that characterize the FAS facial phenotype. Guide 1 is used for Caucasians and all other races with lips like Caucasians.[pediatrics.aappublications.org]
Neurologic Manifestation
  • Neurologists are frequently called upon to evaluate and recommend treatment for children with developmental delay or neurologic manifestations of FAS.[ncbi.nlm.nih.gov]

Workup

The following criteria must be fulfilled to diagnose a child with fetal alcohol syndrome:

  1. Growth deficiency
  2. Facial features characteristic of fetal alcohol syndrome: Measurement of fetal alcohol syndrome facial features is done by a criteria made by University of Washington. The lip and philtrum are measured with the lip philtrum guide. On a 5 point likert scale with representative photographs of lip and philtrum combinations, scores are given ranging from normal (1) to severe (5). Palpebral fissures are measured with calipers in millimeters and then compared to the palpebral fissure growth chart, developed by the University of Washington.
  3. CNS damage
  4. Prenatal alcohol exposure [9]

Amount, frequency and timing of prenatal alcohol consumption can have varied impact on the developing fetus. Consensus exists over alcohol being a teratogen, there is not much data as to what level of exposure is toxic.

Liver Biopsy
  • Light microscopy of the liver biopsy specimen revealed parenchymal fat with portal and perisinusoidal fibrosis.[ncbi.nlm.nih.gov]

Treatment

There is no cure for fetal alcohol syndrome, because the CNS damage is permanent. Epileptic seizures can be treated with anticonvulsants like Phenobarbital, etc. Nutrition should be taken care of as these babies are at high risk of repeated respiratory infections and cerebral palsy.

A multidisciplinary approach is required with active involvement from a pediatrician, physiotherapist, orthopedic surgeon, ENT surgeon and an ophthalmologist. The treatment plan needs to be individualized.

Behavioral therapy is required in many cases as the diagnoses of oppositional defiance disorder, conduct disorder, attention deficit hyperactivity disorder often coexist with fetal alcohol syndrome. Special education services with outcome based approach are required commonly.

The child may have special areas of interest like music, art, singing, composing, reading, computers, mechanics, woodworking, skilled vocations, poetry etc. This special talent needs to be identified in the individual and nurtured with due attention and a professional attitude.

Prognosis

The prognosis is poor. Although not life-threatening, the primary disabilities of fetal alcohol syndrome are the CNS damages due to teratogenicity of alcohol [2]. These patients are more prone to mental health problems like attention deficit hyperactivity disorder (ADHD), depression etc. They can have disrupted school experience. They are found to be delinquent and often need foster home treatment.

Patients have inappropriate sexual behavior and tend to have alcohol and drug addiction. They are usually dependant on family and friends and often need assistance. They have problems with employment and require ongoing job training and coaching.

Research has suggested that a range of effects could arise from maternal prenatal alcohol exposure, so the term fetal alcohol spectrum disorder was discarded for fetal alcohol syndrome along with other conditions resulting from prenatal alcohol exposure [3].

Etiology

Fetal alcohol syndrome develops as a result of the teratogenic effect of alcohol on the developing fetus. It involves a wide spectrum of physical and mental defects and is thus referred to as a syndrome.

Epidemiology

Fetal alcohol syndrome is one of the leading causes of intellectual disability in the developed countries where there is high incidence of alcohol consumption by young women. Fetal alcohol syndrome prevalence rate is 0.2-2:1000 live births in the developed countries.

Sex distribution
Age distribution

Pathophysiology

Alcohol can cross the placental barrier and can cause adverse effects on the developing fetus. It can cause intrauterine growth retardation leading to a small for age baby. It can cause characteristic facial stigmata, damage neurons and can result in intellectual impairment and other psychological and behavioral problems in the child [1]. 

The maternal placenta allows entry of ethanol and other toxic metabolites like acetaldehyde freely into the fetal compartment. The developing fetal nervous system is particularly sensitive to ethanol toxicity. Alcohol affects neuronal proliferation, differentiation, migration of neurons and also the axonal outgrowth.

The main detoxifying organ in adults is liver, fetal liver is incapable of detoxifying alcohol as it is deficient of enzymes alcohol dehydrogenase and aldehyde dehydrogenase required for detoxification of alcohol.

All these result in fetal alcohol syndrome. During the first trimester of pregnancy, alcohol can interfere with migration and organization of neurons, which can lead to structural abnormalities. During the third trimester, alcohol can cause damage to the hippocampus which can create neurological and functional impairments. Alcohol can also affect brainstem and cerebellum both of which are extremely important.

Prevention

Prenatal maternal alcohol consumption is the cause of fetal alcohol syndrome and therefore avoiding alcohol during pregnancy can prevent fetal alcohol syndrome.

Consumption of less than 15 drinks per week has been proven to not lead to fetal alcohol syndrome related effects. However, only one drink per day is allowed as the alcohol pharmacokinetics varies in different individuals and different people can have different teratogenic levels depending on genetic variation. A human fetus is at triple risk from maternal alcohol consumption [10].

Summary

Fetal alcohol syndrome is a constellation of symptoms that develops as a result of consumption of large amount of alcohol by the mother during pregnancy. The exact amount of alcohol required has not been determined but maternal alcohol exposure leads to facial deformities, mental dysfunction and overall growth retardation.

Patient Information

Fetal alcohol syndrome is a disorder caused by ingestion of alcohol during pregnancy. It leads to numerous adverse effects in the development of the fetus. A set of characteristic facial defects are observed along with maximum insult to the developing neurons. Thus, the fetus tends to be small for age and with deformities with slow brain development.

Pregnant women are advised not to have alcohol as alcohol can pass the blood brain barrier and lead to destruction of the brain tissues of the growing fetus.

References

Article

  1. Streissguth AP, Bonthius D. 1997. Fetal Alcohol Syndrome: A Guide for Families and Communities. Baltimore: Brookes Publishing.
  2. Ethen MK, Ramadhani TA, Scheuerle AE, Canfield MA et al. Alcohol Consumption by Women Before and During Pregnancy. Matern Child Health J. 2008 Mar; 13 (2):274-85.
  3. Jones KL, Smith DW. Recognition of the fetal alcohol syndrome in early infancy. Lancet. 1973 Nov 3;302(7836) 999–1001.
  4. May PA, Gossage JP. Estimating the prevalence of fetal alcohol syndrome. A summary. NIAAA. 2001.
  5. Abel EL, Jacobson S, Sherwin BT et al. In utero alcohol exposure: Functional and structural brain damage. Neurobehav Toxicol Teratol. 1983 May-Jun; 5(3): 363–366.
  6. Meyer LS, Kotch LE, Riley EP. Neonatal ethanol exposure: functional alterations associated with cerebellar growth retardation. Neurotoxicol Teratol. 1990 Jan-Feb; 12(1):15-22.
  7. Olegard R, Sabel KG, Aronsson M, Sandin B, et al. Effects on the child of alcohol abuse during pregnancy. Acta Paediatrica Scandinavica. 1979; 275, 112–121.
  8. Renwick JH, Asker RL. Ethanol-sensitive times for the human conceptus. Early Hum Dev . 1983 Jul;. 8(2) 99-111.
  9. Clarren SK, Smith DW et al. Fetal alcohol syndrome. N Eng J Med. 1978 May 11;298(19):1063-7.
  10. Coles CD, Brown RT, Smith IE, Platzman KA, et al. Effects of prenatal alcohol exposure at school age. Physical and cognitive development. Neurotoxicol Teratol . 1991 Jul-Aug;13(4):357-67.

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Last updated: 2019-06-28 10:39