Macrocephaly: causes, symptoms and treatment

The maturational development of brain it is a complex and delicate process. Although human beings are born with a very large head in relation to the body (especially if we compare ourselves with other animals), throughout the first decades of our life our nervous system must still grow and develop so that we can reach a healthy adulthood.

However, during this process there are many things that could go wrong and that, although they are rare, if they appear, they greatly influence our lives. Macrocephaly is an example of this.

• Related article: "The 15 most common neurological disorders"

What is macrocephaly?

Macrocephaly is a biological disorder in which the head circumference is greater than expected for sex and age of a boy or girl. That is, the identification of macrocephaly is carried out by taking measurements of the perimeter of the skull and checking if the cranial vault is larger than normal in healthy people. For this reason, macrocephaly is included within the cranial growth disorders, a category to which microcephaly also belongs.

In addition, it is considered that a correct study of each case of macrocephaly does not depend only on a measurement, but rather a follow-up must be done to see how it evolves. the size of the head in relation to the rest of the body and if the situation is getting worse over time.

This is so because this proportion changes very quickly during the first months of life and, in fact, Between birth and 6 years of age, the size of the body below the neck increases rapidly.

On the other hand, the concept of macrocephaly is not in itself a disorder but a term that is used to superficially describe an alteration.

How often does it appear?

Currently there are no statistics on the prevalence of macrocephaly that have been extracted from related research, but it is estimated that it is a rare malformation present in less than 5% of people.

However, as is always the case in these cases, it is possible that certain poorly studied populations are more prone to suffer this type of complications during the first months of life, perhaps due to genetic reasons or due to contamination. After all, during pregnancy you are very sensitive to external conditions, and small alterations can, in some cases, promote the appearance of diseases in the fetus.

In addition, it is believed that macrocephaly is more common in males and that it usually appears in pregnancy or in the first months of life, for which most cases are examples of infantile macrocephaly.

Causes

Macrocephaly can be caused by a wide variety of disorders. Many times it is of hereditary root, while in others it is caused by injuries or complications during pregnancy or childbirth.

For example, many cases of macrocephaly are due to a disorder known as hydrocephalus, in which more cerebrospinal fluid (a substance that envelops the brain and spinal cord) that can fit inside the skull. This means that in the first months of life the walls of the skull are more "dilated" than normal. to accommodate so much fluid, since at this vital stage the head is much less hard than at the adulthood.

Macrocephaly it may also be due to abnormal growth of the skull or brain bones, which is compressed against meninges and through it presses the bones of the cranial vault.

There is also other disorders in which macrocephaly may also appear, such as neurofibromatosis, bone growth disorders, intracranial bleeding, Hurler syndrome or dwarfism.

Types of macrocephaly

There is a brief classification that serves to distinguish between different types of macrocephaly based on their causes. However, it must be taken into account that even within each type there are different variants that will depend on each individual case, such as the area where the skull bulges more or the areas of the brain more damaged.

In any case, the types of macrocephaly are as follows:

Primary macrocephaly

This type of macrocephaly is characterized by being caused by increased volume and weight of the brain. For example, it occurs due to an abnormal multiplication of stem cells. It has genetic causes and is also known as macroencephaly.

Secondary macrocephaly

In this class of macrocephaly, the increase in the skull is due to biological processes that are not due to an enlargement of the brain itself, but from other related substances that occupy the head space. For example, hydrocephalus produces this variant.

Macrocephaly due to bone malformation

Some cases of macrocephaly are explained by abnormal bone development. For example, they may be due to early closure of the cranial sutures, resulting in bulging caused by the abnormal development of the nervous system produced by the chain reaction that supposes not having room to expand in a Given moment.

Diagnosis and associated symptoms

In many cases macrocephaly can be detected during pregnancy thanks to the use of ultrasounds. However, in non-congenital macrocephaly this may appear somewhat later, with the manifestation of certain disorders, and is diagnosed in pediatric consultations.

Macrocephaly can present a wide variety of associated symptoms, depending on its causes and the intensity of this alteration. Among them, the following stand out:

• Cognitive disturbances
• Vomiting
• Convulsive crisis
• General developmental delay
• Headaches
• Intracranial hypertension
• Irritability

Some of these symptoms may subside over time and depending on the intervention that is carried out, although they can also become more intense, depending on the case.

Forecast

The way in which macrocephaly develops and its associated symptoms depends on the kind of alteration that is producing this phenomenon.

In some cases, such as hydrocephalus, the life span of the person may be in danger if surgery is not performed (which will consist of discharging the surplus cerebrospinal fluid). In others, neither the life nor the cognitive abilities of the child will be compromised. In fact, cases in which macrocephaly is not associated with the appearance of mental retardation are very frequent.

Treatment

There is no specific treatment that targets the disappearance of macrocephaly. However, there are those whose objective is to intervene on the symptoms associated with the disorder that is causing this alteration.

Many of them are pharmacological and psychiatric, while others are psychological and focus on the cognitive stimulation of the child.

Bibliographic references:

• Adams, H.H.; Hibar, D.P.; Chouraki, V.; Stein, J.L.; Nyquist, P.A.; Renteria, M.E.; Trompet, S.; Arias-Vasquez, A. et al. Novel genetic loci underlying human intracranial volume identified through genome-wide association. Nature Neuroscience, 19 (12): pp. 1569 - 1582.
• Portellano, J. TO. (2005). Introduction to neuropsychology. Madrid: McGraw Hill.
• Williams, C, A.; Dagli, A.; Battaglia, A. (2008). Genetic disorders associated with macrocephaly. American Journal of Medical Genetics, 146A (16): pp. 2023 - 2037.