CONGENITAL MALFORMATIONS – ANENCEPHALY AND MICROCEPHALY Presentation, Symptoms, Diagnostic Evaluations and Management

CONGENITAL MALFORMATIONS – ANENCEPHALY AND MICROCEPHALY -  Presentation, Symptoms, Diagnostic Evaluations and Management 

CONGENITAL MALFORMATIONS – ANENCEPHALY AND MICROCEPHALY Presentation, Symptoms, Diagnostic Evaluations and Management 

ANENCEPHALY

Anencephaly is a cephalic disorder that results from a neural tube defect that occurs when the cephalic (head) end of the neural tube fails to close, usually between the 23rd and 26th day of pregnancy, resulting in the absence of a major portion of the brain, skull, and scalp. Possible causes include environmental toxins and low intake of folic acid by the mother during pregnancy.

PRESENTATION

The National Institute of Neurological Disorders and Stroke (NINDS) describe the presentation of this condition as follows: A baby born with anencephaly is usually blind, deaf, unconscious, and unable to feel pain. Although some individuals with anencephaly may be born with a main brain stem, the lack of a functioning cerebrum permanently rules out the possibility of ever gaining consciousness. Reflex actions such as breathing and responses to sound or touch occur.

SYMPTOMS

  • Absence of the skull
  • Absence of the brain (cerebral hemispheres and cerebellum)
  • Facial feature abnormalities
  • Cleft palate
  • Congenital heart defects


 

DIAGNOSTIC EVALUATIONS


  • Pregnancy ultrasound
  • Amniocentesis
  • Alpha-fetoprotein level
  • Urine estriol level
  • Pre-pregnancy serum folic acid test 


MANAGEMENT

There is no cure or standard treatment for anencephaly. Treatment is supportive. Due to the lack of development of babies brain, about 75 percent of infants are stillborn and the remaining 25 percent of babies die within a few hours, days or weeks after delivery from cardio respiratory arrest.

It is important for women who may become pregnant to get enough folic acid. There is good evidence that folic acid can help reduce the risk of certain birth defects, including anencephaly. Women who are pregnant or planning to become pregnant should take a multivitamin with folic acid every day. Many foods are now fortified with folic acid to help prevent these kinds of birth defects. Getting enough folic acid can reduce the chance of neural tube defects by 50 percent

MICROCEPHALY

Microcephaly is a rare neurological condition in which an infant has a significantly smaller than normal head size because the brain has not developed properly or has stopped growing. Literally, the term “microencephaly” means “small head”. Microencephaly can be present at birth or it may develop in the first few years of life.

CAUSES AND RISK FACTORS

Microcephaly can be caused by exposure to harmful substances during the fetal development, or it may be associated with genetic problems or syndromes that may run in families. The following may predispose a fetus to problems affecting the development of the head during pregnancy:

  • Exposure to hazardous chemicals/substances
  • Methylmercury poisoning
  • Lack of proper vitamins and nutrients in the mother’s diet
  • Cytomegalovirus, rubella (German measles) or varicella-zoster (VSV) infection
  • Prescription or illegal drug and alcohol consumption
  • Untreated phenylketonuria (PKU)
  • Chromosomal abnormalities such as Down syndrome


 

CLINICAL MANIFESTATIONS

Depending on the severity of the syndrome, children with microencephaly may have:

  • Baby’s head is very small
  • Mental retardation
  • Delayed motor functions and speech
  • Increased movement of the arms and legs (spasticity)
  • Facial distortions
  • Dwarfism or short stature
  • Hyperactivity
  • Seizures
  • Difficulties with coordination and balance
  • Other brain or neurological abnormalities
  • Poor feeding
  • Developmental delays
  • Intellectual disabilities


 

DIAGNOSTIC EVALUATIONS

  • Birth and family history and physical exam
  • Prenatal ultrasound
  • Head CT or MRI
  • Blood and urine tests


 

MANAGEMENT

Generally, there is no treatment that will enlarge child’s head or reverse complications of microencephaly. Treatment is symptomatic and supportive. Treatment focuses on ways to manage child’s condition. Early childhood intervention programs that involve physical, speech, and occupational therapies help to maximize abilities and minimize dysfunction. Medications are often used to control seizures, hyperactivity, and neuromuscular symptoms. Genetic counseling may help families understand the risk for microcephaly in subsequent pregnancies.

 

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