Human cubs, with large round heads, account for 1/4 of the entire body length, are very cute. But if the head circumference is too large, it will also make parents worry, is there water in it, is it the last time you fell out of bed and caused cerebral hemorrhage, will it be stupid?
During the physical examination, the doctor said that the child's head circumference is large, and further examination is needed? Let's talk a little bit about it today.
Simple rough version
Head circumference greater than 97 percentile indicates that the head is large, not the 50th percentile, if greater than 97 percentile needs attention, clear the cause.
The head circumference is not large, but the head circumference continues to increase by more than 1 curve during the physical examination, or the head circumference increases by more than 2 cm per month within the age of 6 months, and it is necessary to consider that the head circumference increases too quickly and needs attention.
The above problems, at the same time there are symptoms of cranial hypertension, intracranial hemorrhage, syndrome manifestations, metabolic problems, and developmental delay, relevant examinations must be carried out.
If the child is completely normal, just a big head, or grows fast, measure the parent's head circumference, use the Weaver curve to determine whether it is familial megacephalus, and if it is the problem, there is no need for imaging tests and no treatment.
It is enough for everyone to learn how to evaluate whether it is a benign familial giant brain.
No.1
How to make it clear that the head is big?
This is very simple, that is, to assess whether the head is large by the head circumference.
Now when you take your child for a physical examination, you will measure the head circumference of your child before the age of 3, and if the head circumference exceeds the 97th percentile on the growth curve, it is a large head, also known as macrocephaly [1].
The head circumference (Occipitofrontal circumference, OFC) is measured by:
Go through the baby's eyebrow arch (where the eyebrows are raised above the eyebrows) and the posterior occipital bulge (where the back of the head is raised), and this length is the head circumference.
Draw this value to the head circumference curve (shown in the figure below), if it is above the highest red line, it will indicate that the head is large, but don't worry too much, it does not necessarily mean that there is a problem.
The picture above is the head circumference curve of boys aged 0-5 years
The picture above is the curve of the head circumference of a 0-5 year old girl
No.2
If the head circumference is greater than the 97th percentile, is there a problem?
Not necessarily.
Let's first look at the significance of the greater than 97 percentile: the head circumference of a large number of children of the same age and the same sex is counted, from low to high, and the largest group of people has a head size between 3% and 97%.
The lowest 3% of the population, who think their heads are small, the largest 3% of the population, think their heads are large.
The big head here refers to the size of the unsociable, which is beyond the scope of most people in statistics, although it indicates "abnormality", but it does not mean that there is necessarily a problem.
For example, a large child with a large head is a normal mutation, like a benign familial megaencephalon, which has no effect on the child at all, but previous studies have shown that children with a head circumference of 0.5 cm above the 98th percentile have an increase in IQ value at the age of 4.
These unaffected children, in addition to the large head, there is no other abnormality, such as normal growth and development, no special facial features and other signs, no abnormal manifestations of the neuromuscular system, such as anterior fontanelle bulge, headache, muscle weakness and other problems.
But everyone also knows the power of statistics, you are not in the normal range, or prompt to pay attention, if the child has other abnormal performance at the same time, it must be a problem, see Article 5 for details.
No.3
What is most likely to cause the brain?
The size of the head is the final result, and the volume of any component of the skull (brain, blood, cerebrospinal fluid, skull) will lead to this result.
For example, the benign familial megacephalus mentioned above is caused by the increase in brain volume.
In some metabolic diseases, such as leukodystrophy, lysosomal storage disease (such as mucopolysaccharide disease), and organic acid disease, metabolites cause brain cell damage, swelling, etc. [2], and the brain becomes larger.
If there is intracranial hemorrhage, hydrocephalus, intracranial tumors, infections, etc., the intracranial pressure is increased, the skull is thickened, and the skull will be enlarged.
Starting below, let's talk about common causes and treatments.
No.4
What is a benign familial megacephaly?
Familial megacephaly seems to be the most common cause of mild megacephaly, and parents can breathe a sigh of relief when they see it here.
These children have normal neurological examination, normal development, no clinical features suggestive of specific syndromes (such as special facial features), and no family history of neurological abnormalities or developmental problems.
These children are born with large heads but normal body size. The head circumference is mostly above the 98 percentile (it may be 2-4 cm tall), but it is parallel to the curve and does not get higher and higher from the curve.
The head circumference may increase by 0.6 to 1 cm per week (0.4 cm per week in normal terms), and generally by 6 months of age, the head growth rate slows to normal, but the head circumference is still large.
If all of the above conditions are met, to consider this problem, the diagnosis of familial megacephalus can be diagnosed by measuring the parental head circumference and applying the Weaver curve.
If the child's standard head circumference score is within the normal range predicted by the Weaver curve parent's standard head circumference score, and the child's head circumference size is within the mean +3.5 standard deviation (3.5 SD), the disease is considered and ultrasound or cranial MRI is not required.
So how? Here's an example from uptodate.
A 9-month-old boy with a head circumference of 49.5 cm, well above the 97 percentile of the head circumference curve, as shown in the following figure:
But this child's physical examination, development, family history, etc. are completely normal, there is no recent intracranial infection, there is no head trauma problem, then consider the familial megaencephalephaly problem, we measure the parents, assess the impact of the parents' head circumference on the child.
The head circumference of the father is 59.5 cm, and the head circumference of the mother is 59 cm. The standard score (SS) of the child's and parents' head circumference is calculated separately, and the formula is: (head circumference - standard value)/SD.
The head circumference is the measured result, the standard value (Mean) and SD are shown in the figure below, and the standard value of the parents is calculated as 18 years old.
1. Your child's standard score for head circumference = (49.5-45.75)/1.28 = 2.93, using the value in the first red box in the image above.
2. The father's standard head circumference score = (59.5-55.95) / 1.34 = 2.65, using the value in the second red box in the image above.
3. The mother's head circumference standard score = (59.0-54.94) / 1.40 = 2.9, using the value in the second red box in the image above.
4. The average standard score of parents' head circumference = (2.65 + 2.9) / 2 = 2.78.
Mark the parent's average head circumference standard score of 2.78 on the Weaver curve, that is, make a vertical line on the abscissa (red), and the child's standard score of 2.93 on the curve, that is, the vertical coordinate makes a vertical line (black).
The intersection of the two lines is at point A in the following figure, making a point A within two blue curves, indicating that the child's head circumference does not exceed the parental range, considering that genetic factors cause the child's head to be large.
At this time, we look at whether the child's head circumference is within the mean value +3.5 standard deviation (3.5 SD), calculated according to the data in the first red box of the above standard value and SD figure:
45.75+3.5X1.28=50.23cm。
The child's head circumference is 49.5 cm, which is smaller, and can be diagnosed as a benign familial megacephalus, without additional tests, and can be observed.
If in this example, the child's head circumference exceeds the mean +3.5 standard deviation, some chromosomal dominant genetic disorders, such as Cowden syndrome, may begin with a large head and no other manifestations.
Cowden syndrome is a cancer susceptibility syndrome, where affected individuals are at increased risk of developing thyroid malignancy and women are at risk of early breast cancer.
No.5
When do I need to be aware? How to check?
In fact, a simple sentence is that in addition to the above can be diagnosed as a benign familial megacephalus, other conditions may indicate a problem, and all need to be paid attention to.
The benign familial megacephalus needs to exclude other neurological symptoms, syndromes, etc., which can also be said to be an exclusionary diagnosis. Let's use the following diagnostic ideas to talk about how to eliminate other problems, that is, which situations need attention and how to check.
This diagnostic idea is to receive a child with a head circumference greater than 97 percentiles, and to carry it out in order without leakage or over-examination.
1
Be sure if there is an emergency
Emergencies of cranial enlargement are increased intracranial pressure, severe hydrocephalus, intracranial hemorrhage, or intracranial infection.
If your child has headaches, vomiting, impaired consciousness, papilledema, standing instability, irritability, fever, meningeal irritation, etc., it is severe and requires immediate examination and treatment, and depending on the emergency and state of the condition, choose to have a head CT or severe magnetic (MRI) examination.
2
Evaluate for some syndrome manifestations
The simple summary here is to give the child a detailed physical examination, and if there is a relevant abnormality found, it is necessary to consider this problem, such as:
Your child has abnormal skin, many and large coffee spots, freckles in the armpits, and consider whether there is a type 1 neurofibroma.
Children with umbilical bulges, asymmetrical limb sizes, large tongues, height and weight, to consider Bur-Wei syndrome, this has been written before: there are small holes and large tongues in the ears, which need to be paid attention to.
Other manifestations of your child, such as facial abnormalities, skull deformities, short stature, skeletal abnormalities, heart abnormalities, and digestive tract abnormalities, may indicate possible syndrome problems.
If there are the above abnormalities in the clinical examination, the syndrome is considered and referred to a specialist for examination and confirmation.
3
Whether the child is stunted
If the child's head is large and there is developmental delay, such as cognition, language, social interaction, movement, etc., it is necessary to conduct a brain magnetic examination to determine whether there is a problem with intracranial diseases, such as hydrocephalus, etc. If the child has sunset eye performance at the same time, it is more suggestive of this problem, and an MRI is required.
At the same time, at this time, we should also pay attention to genetic metabolic diseases, if you can smell the child's urine has a special taste, such as rat urine smell or sweet, etc., to consider metabolic diseases.
4
Completely normal child
If the child is well developed, has no neurological symptoms, has no syndrome manifestations, and is only a head circumference greater than 97 percentile, the benign familial megacampere in article 4 above can be evaluated:
If the child's standard head circumference score is less than the parent's range, and the head circumference is less than the mean +3.5 standard deviation, a benign familial megacephalon is diagnosed without any testing;
If the child's standard score of head circumference is greater than that of the parents, and the head circumference is greater than the mean + 3.5 standard deviation, it is impossible to diagnose benign familial megacephalus, and some chromosomal dominant genetic diseases need to be considered;
The child's standard score of head circumference is greater than the range of parents, and it is necessary to consider a skull examination, if the child's fontanelle is not closed, ultrasonography can be performed, and if the fontanelle is closed, it is recommended to have an MRI, which has not yet been agreed.
No.6
The head is not big, there are no symptoms, grow fast?
If it grows too fast, it is not good, for example, within 6 months of age, the child's head circumference grows more than 2cm per month, you need to consider that there is an abnormal cause, the assessment method is the same as the order in the previous one, even if the child is completely normal, it is recommended to perform ultrasound examination to determine whether there is intracranial lesions, anyway, ultrasound is not radiation, even if it is completely normal, it is worth checking.
If you look at the head circumference curve, the recommendation given now is if the head circumference continuously exceeds 1 / more than one main curve during the normal physical examination, as shown in the following figure, it is necessary to consider whether there is a problem.
The normal physical examination time is 1, 2, 4, 6, 9, 12, 15, 18, 24, 30, 36 months of age, the main head circumference curve is the 10th, 25th, 50th, 75th, 90th percentile, you can use the following WHO figure.
The picture above is a curve of the boy's head circumference
The picture above is a curve of the girl's head circumference
This recommendation is somewhat problematic, because normal children are growing up, and during the two physical examinations, the head circumference may exceed 1 main line, and if it exceeds 1 main line, it will be checked, which is somewhat excessive.
What to do then? If the head circumference continues to increase, beyond 1 curve, if just exceeded, it is basically fine, if the excess is particularly much, such as the last time the head was around a point on the 10th percentile, this time it is close to the 50 percentile line, although it is only beyond a 25 percentile, but the amplitude is large, you need to pay attention.
At this time, the parent's head circumference can be measured to see if the child's head circumference at this time is within the Range of the Weaver curve of the parent's head circumference, if so, there is no need for imaging examination, if it is exceeded, it must be examined.
If the Weaver curve is within the bounds of the parent's head, or if this assessment cannot be performed, the parent wants to check, can it be checked? Of course.
If the head circumference exceeds 2 main curves during the two physical examinations, or the child has neurological symptoms, the examination is carried out directly, and when the fontanelle is not closed, an ultrasound is performed, and the anterior fontanelle is closed, and the head MRI is performed.
No.7
The head is indeed big, but there are no symptoms, do you want to check?
After this is over, it is 04 in Article 5, and you can look at it again.
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