Macrocephaly - Causes, Symptoms, Diagnosis, and Treatment

Introduction:

Baby head measurements are as crucial as height and weight for tracking growth.

Macrocephaly is the medical term for having a large head. Most often, it is not a serious condition and is benign or harmless. Certain cases of macrocephaly could indicate a more serious medical condition, such as a genetic syndrome or a brain tumor. However, the baby's larger head size could be a harmless genetic trait that does not require treatment. This is known as benign familial macrocephaly.

What Is Macrocephaly?

Macrocephaly is defined as having a head circumference of more than two standard deviations (SD) above the average for age and gender. In other words, their head is bigger than the 98th percentile. It must be distinguished from megalencephaly, which is increased brain parenchyma size. In infants and children, head circumference is measured to track head growth. It is also referred to as occipitofrontal circumference (OFC), and it measures the size of the cranium. Macrocephaly can be the first symptom of various congenital and acquired neurologic conditions, or it can simply be a familial trait.

How Is Macrocephaly Classified?

Macrocephaly is classified as follows:

• Disproportionate Macrocephaly: The child's head is larger than is appropriate for their overall size.

• Proportionate Macrocephaly: The head seems the right size for the body (in other words, the child has a large body and a large head).

Many people who have large heads or skulls are healthy.

What Are the Risk Factors for Macrocephaly?

There are some risk factors for macrocephaly, such as genetics. Familial macrocephaly is a genetic disorder. Children with autism are also thought to have a higher incidence of macrocephaly. According to one study, 15 to 35 percent of autistic children will have macrocephaly. There is no evidence that children of a particular gender, nationality, or race are more likely to develop macrocephaly.

What Causes Macrocephaly?

The causes of macrocephaly are diverse. However, the most common cause, benign familial macrocephaly, characterized by enlargement of the subarachnoid spaces, accounts for nearly half of all cases. Infants with benign familial macrocephaly often have no other symptoms besides a large head.

Other causes are discussed further below:

• Skull Bone Enlargement

  • Hyperostosis cranii - It is a condition associated with osteogenesis imperfecta, achondroplasia, and osteopetrosis.

  • Secondary enlargement is caused by bone marrow expansion, as in thalassemia major.

  • Increase in cerebrospinal fluid volume.

• Hydrocephalus: It is the accumulation of fluid in the deep cavities within the brain. It occurs in conditions such as;

  • Papilloma of the choroid plexus.

  • Familial benign macrocephaly.

• Megalencephaly: It refers to an abnormally large brain and head size of the individual, seen in conditions such as

  • Leukodystrophies - Canavan disease, Alexander disease, megalencephalic leukoencephalopathy with subcortical cysts.

  • Lysosomal storage disorders - Tay-Sachs, mucopolysaccharidosis, gangliosidosis.

  • Neurocutaneous disorders - Tuberous sclerosis, Sturge-weber syndrome, neurofibromatosis, Gorlin syndrome.

  • Autism spectrum disorder (ASD).

  • Other syndromes include Fragile X, Cowden, and Sotos syndromes.

• Increased Intracranial Pressure (ICP)

  • CNS (central nervous system) infections.

  • Pseudotumor cerebri.

  • Subdural collections, including hygromas.

• Mass Lesions and an Increase in Blood Volume.

  • Tumor

  • Intraventricular hemorrhage.

  • Subdural hematoma.

  • Arteriovenous malformation.

What Are the Signs and Symptoms of Macrocephaly?

The most apparent sign of macrocephaly is an abnormally large head. In cases of benign familial macrocephaly, this is the only symptom. However, if an underlying condition causes macrocephaly, an infant may experience additional symptoms.

These may include:

• Delays in reaching developmental milestones.

• Simultaneous diseases like epilepsy, autism, and other mental disorders.

• Veins bulging on the child's head.

• A downward gaze of the child's eyes.

• Firm or bulging gaps in the child's skull due to incomplete bone formation.

• Poor appetite.

• Excessive irritability.

• Vomiting.

• Sleepiness.

What Are the Complications of Macrocephaly?

The health consequences of macrocephaly vary depending on the condition that causes the enlarged head.

The followings are some specific conditions and potential complications:

• Complications of megalencephaly, in which an infant has an abnormally large and usually malfunctioning brain, can include delayed development, partial paralysis, seizures, and brain cortex and spinal cord dysfunction.

• Complications of hydrocephalus, a condition in which cerebrospinal fluid accumulates in the brain, can include delayed intellectual development and physical disabilities.

• Complications of neurocutaneous disorders, a rare group of disorders involving the nervous system and skin, may include an increased risk of seizures and the development of certain tumors.

• Complications of Sotos syndrome may include developmental delays and coordination issues.

How Is Macrocephaly Diagnosed?

Doctors usually diagnose macrocephaly during a routine physical examination. For example, a doctor will measure an infant's head circumference during a physical exam by wrapping a measuring tape around the head and aligning it just above the brows.

To meet the macrocephaly criteria, the infant's head circumference must be at or above the 97th percentile for their age and gender. This means the infant's head circumference is larger than that of 97 percent of similar infants.

Suppose a doctor suspects an infant has macrocephaly. In that case, he or she will conduct a thorough medical history to determine if the condition is due to an underlying condition and may frequently advise imaging tests such as a CT (computed tomography) scan, ultrasound, or MRI (magnetic resonance imaging). These tests will assist the doctor in determining whether there is a buildup of fluid in the brain, which could lead to increased pressure and other complications.

How Is Macrocephaly Treated?

The underlying cause determines treatment for macrocephaly.

• Benign Familial Macrocephaly and BESSI (Benign Enlargement of the Subarachnoid Spaces in Infancy)

  • If the child has no neurologic symptoms, is meeting developmental milestones, and has a family history of a larger-sized head, head size is probably hereditary (runs in the family), and no treatment is required.

  • BESSI is also a benign (harmless) condition. There is extra cerebrospinal fluid in areas of the brain in this condition, but it is not harmful and resolves on its own without treatment.

• Macrocephaly Linked to Genetic Causes

  • Physical therapy.

  • Occupational therapy.

  • Speech and language therapy.

  • Behavioral therapy.

• Brain Bleeds or Fluid Buildup in the Brain: Surgery is required to relieve the fluid buildup or stop the brain bleeding.

• Brain Tumor: Treatment includes surgery, chemotherapy, radiation, and steroids.

Conclusion:

Macrocephaly refers to infants born with or developing an abnormally large head shortly after birth. It is frequently benign and genetically transmitted but can also indicate problems such as fluid buildup in the brain or a genetic disorder. While benign macrocephaly does not require treatment and is typically outgrown by early childhood, treatment may be necessary in other cases. The prognosis is primarily determined by the underlying condition causing the macrocephaly. Children with benign familial macrocephaly have a good prognosis and rarely develop complications. An infant with macrocephaly due to an underlying condition, such as a brain tumor or a genetic syndrome, will require a customized treatment plan.