The document discusses normal head growth and measurement, cerebrospinal fluid physiology and circulation, and the clinical approach to infants with abnormal head sizes. Key points include: head circumference should be measured regularly from birth to age 2-3 years and plotted on a growth chart; cerebrospinal fluid is produced in the brain ventricles and absorbed through arachnoid granulations; microcephaly is defined as a head circumference below the 2nd percentile and can be caused by genetic or acquired factors, while macrocephaly is above the 98th percentile and can be due to increased brain, blood, or fluid volume or intracranial pressure. A full history and physical exam is needed to evaluate the cause in infants with

1. Approach To Abnormal Head
Moath Alkeaid
ID:438009612
Saleh Alorainy
ID:438020973

2. Contents
1. Normal head growth
2. Measurement and monitoring head
circumference
3. CSF physiology and circulation
4. Etiology of microcephaly and
macrocephaly
5. Clinical approach to infant with large
and small head size
6. Summary

3. Normal Head Growth
Saleh Alorainy

4. • All Aid in Bone movement and brain
growth during normal growth.
• Fontanelles are open at birth.
• Posterior fontanelle Close at 8th week.
• Anterior fontanelle close between
12th or 18th month.

5. • Normal Head circumference at birth is from
33-37 cm
• In a healthy infant, head circumference
increases by:
 5 cm during first 3 months.
 4 cm between 3–6 months.
 2 cm between 6–9 months.
 1 cm between 9–12 months.
• 80% of adult head size is achieved < 5 years
old

6. Mean Normal Head Circumference
• 35cm at birth
• 47cm at 12 months
• 49cm at 2 years
• 50cm at 3 years
• 52cm at 6 years
• 53cm at 10 years
• 56cm for adults

7. Measurement and monitoring head
circumference
Saleh Alorainy

8. Why do we measure
head circumference?
• Rapid brain development occurs
from birth till 3 years old
• Main component of the growth
patterns (Growth chart)
• To detect deviations from normal
growth patterns. (Serial Measures)

9. How to measure head
circumference
1. Use a measurement tape
(Nonflexible)
2. Start From the supraorbital ridge
(above the eyebrows)
3. Make sure that the tape passes the
most prominent posterior part
(Occipital protuberance)
4. Repeat Measurement three times,
then record the largest number.
5. Plot it in a growth chart.

11. Growth Chart (Saudi Arabia)

12. Microcephaly & Macrocephaly
• Microcephaly: “defined as a head circumference 2 standard deviations (SDs)
below the mean for age and sex or roughly less than the 2nd percentile”.2
• Macrocephaly: “defined as a head circumference greater than 2 SDs above the
mean or greater than the 98th percentile”.2

13. Microcephaly Macrocephaly

14. CSF physiology and circulation
Saleh Alorainy

15. CSF Physiology
• Cerebrospinal fluid (CSF) is a clear, colorless body fluid found in the brain and
spinal cord. It is produced by specialised ependymal cells in the choroid plexuses
of the ventricles of the brain, and absorbed in the granulations.
• CSF acts as a cushion or buffer, providing basic mechanical and immunological
protection to the brain inside the skull.
• CSF also serves a vital function in the cerebral autoregulation of cerebral blood
flow.

16. Composition

17. Formation
• CSF is formed by the epithelial cells of the choroid plexus.
• Transport mechanisms in these cells secrete some substances from blood into CSF
(e.g., Na+, Cl−,HCO3−, and water) and absorb other substances from CSF into
blood (K+).
• Molecules such as protein and cholesterol are excluded from CSF because of their
large molecular size.

18. Flow

19. Secretion
• depends mainly on active transport of sodium ions through the epithelial cells
lining the outside of the plexus.
• The sodium ions in turn pull along large amounts of chloride ions as well because
the positive charge of the sodium ion attracts the chloride ion’s negative charge.
• which then causes almost immediate osmosis of water through the membrane,
thus providing the fluid of the secretion.

20. Absorption
• Masses of arachnoid villi form structures
called arachnoidal granulations
• The endothelial cells covering the villi have
vesicular passages directly through the
bodies of the cells large enough to allow
relatively free flow of:
 cerebrospinal fluid
 dissolved protein molecules
 particles as large as red and white blood
cells into the venous blood.

21. Etiology of microcephaly and
macrocephaly
Moath Alkeaid

22. Etiologies of microcephaly
• It is a variety of genetic abnormalities and environmental insults that can affect brain
development, resulting in microcephaly and/or microcephaly of congenital or postnatal
onset
• Head circumference below the 2nd centile and it can be caused by:
1) familial, when it is present from birth and development is usually normal
2) an autosomal recessive condition; when it is associated with developmental delay
3) congenital infection
4) aqcuired after an insult to the developing brain, for example: perinatal hypoxia,
hypoglycemia or meningitis, when it’s accompanied by cerebral palsy and seizuers.

23. Etiologies of microcephaly (cont.)
• Isolated microcephaly:
Present at birth an uncomplicated by anamolies outside the brain
• Metabolic disorders:
Metabolic disorders are associated with microcephaly however the prevelance of metabolic disorders
among patients with microcephaly is low, the disorders include aminoacidurias, organic acidurias, urea
cycle disorders and certain storage diseases
• Enviromental factors:
1. CNS infections
2. In utro toxin exposure
3. Hypoxic-ischemic insult
4. Severe malnutrition

24. Etiologies of microcephaly (cont.)
• Neuroanatomic abnormalities:
• Neural tube defect:
Encephalocele or spinal neural tube defect can be associated with abnormal brain
development and microcephaly
• Fetal brain disruption sequence:
It is characterized by severe microcephaly of prenatal onset, overlapping cranial sutures,
prominence of the occipital bone, and scalp rugae
• Hydranencephaly:
It is a vascular insult to the brain in which fluid-filled cavities replace the cerebral hemisphere

25. Etiologies of microcephaly (cont.)
• Craniosynostosis
It is charectrized by premature fusion of one or more sutures that will lead to distorsion
of head shape
Most commonly affecting the sagittal suture resulting in long, narrow skull
The fused suture may be felt or seen as a palpable ridge and can be confirmed with skull
X-ray or cranial CT scan
Can be treated surgically because of the increased intracranial pressure and/or for
cosmotic effect

27. Etiologies of macrocephaly
• Macrocephaly is a head circumference above the 98th centile, causes of macrocephaly are:
• Increased brain parenchyma “megalencephaly”
a) Anatomic megalencephaly
b) Metabolic megalencephaly
c) Other causes
• Increased cerebrospinal fluid “hydrocephalus”
a) Non-communicating hydrocephalus
b) Communicating hydrocephalus

28. Etiologies of macrocephaly (cont.)
• Increased blood
a) Hemorrhage
b) AVM
• Increased bone mass
• Increased intracranial pressure
• Space-occupying lesion

29. Clinical approach to infant with large and
small head size
Moath Alkeaid

30. Take full history
• Neonatal history; birth weight, length, OCF and growth trajectory
• Developmental history; loss or attainment of milestones
• History of associated symptoms; headache, seizures, cognitive decline and
vomiting
• History of predisposing factors for hydrocephalus; meningitis and prematurity with
intraventricular hemorrhage
• Family history; large OCF

31. Take full history
• Prenatal history; epilepsy, PKU, DM, medications, tobacco, alcohol and radiation
exposure
• Birth history; perinatal complication, metabolic disorders and infections

32. Physical examination
• General appearance inspection; look for any dysmorphic featires that suggest a
particular syndrome
• OFC; should be measured and compaired with previous measurments
• Weight and hight trajectories
• Head assessment for fontanelles and auscultation for intracranial bruit

33. Physical examination
• Eyes; look for papilledema and cataracts
• Skin; look for macules, angiomas or jaundice
• CVS; congenital heart disease
• Abdomen; for organomegaly
• Musculoskletal system; for short limbs
• Neurological assessment; Deep tendon reflexes, hypotonia, spasticity and
intellectual ability

34. Radiological investigations
• A rapid increase in OCP even if it still less than 98th percentile suggests raised ICP
that may be due to hydrocephalus, subdural hematoma or brain tumor
• It must be investigated by cranial ultrasound if the anterior fontanelle is still open,
otherwise by CT scan or MRI

35. Differential diagnosis
• Craniosynostosis
• Scaphocephaly: condition in which the skull is elongated from the front to back in
the sagittal plane due to premature fusion of the sagittal suture
• Brachycephaly: it is a condition where the occipital bone is flat, causing the head
to widen and the forehead to bulge out due to premature closure of both coronal
sutures

36. Differential diagnosis
• Plagiocephaly: it is a condition in which the head shape is asymmetrical in the
sagittal or coronal planes , due to premature unilateral closure of coronal or
lambdoid sutures

37. Differential diagnosis
• Trigonocephaly : narrow pointed forehead with hypotelorism due to premature
closure of metopic suture

38. • Oxycephaly (acrocephaly,
turricephaly): high narrow tower
shaped head due to premature closer
of all sutures

39. Summary
Saleh and Moath

40. Summary
• Posterior fontanel closed at 8 weeks while anterior fontanel closes at 12-18 months
• Head circumference measurement is crucial to be measured from birth to 2-3 years
• Normal head circumference at birth ranges from 33-37 cm
o Steps in measuring head circumference:
a) Use flexible non stretchable tape
b) Put it on supraorbital ridge anteriorly and occipital protuberance posteriorly
c) Take the measurement 3 times and plot the largest measure against the growth
chart
• A major function of the CSF is to cushion the brain within its cavity.
• CSF originates as secretion from the choroid plexuses in the four ventricles, mainly in
the two lateral ventricles.
• Flow of CSF: Lateral Ventricle Foramen of Monro Third Ventricle
Aqueduct of Sylvius Fourth Ventricle Foramen of Magendie and Luschka
Subarachnoid Space of brain and spinal cord Reabsorption via arachnoid
granulations.

41. Summary
• Causes of macrocephaly include: megalencephaly, increased CSF, increased blood,
increased bone, increased ICP, and mass lesions.
• The occipitofrontal circumference for macrocephaly is greater than two standard
deviations above the mean (≥97th percentile).
• Causes of microcephaly include: isolated, numerous syndromes, metabolic disorders,
environmental factors, neuroanatomic abnormalities, and craniosynostosis.
• Microcephaly is defined as OFC >2 SD below the mean (<3rd percentile)
• To clinically approach and infant, we take full detailed history and a general
examination of the whole body to know the etiology and treat the patient according to
it.
• Craniosyntosis has many types and it is known as premature fusion of one or more of
the sutures that lead to abnormal head shape.
• Scaphocephaly is the most common type of craniosyntosis.

42. References
1. Illustrated textbook of paediatrics, 5th edition
2. Sniderman A. Abnormal head growth. Pediatr Rev. 2010 Sep;31(9):382-4. doi:
10.1542/pir.31-9-382. PMID: 20810704.
3. NELSON ESSENTIALS OF PEDIATRICS, EIGHTH EDITION INTERNATIONAL EDITION
4. Boom J.A., 2020, Microcephaly in infants and children: Etiology and evaluation.
5. Alhawasi, Manual Of Clinical Pediatrics
6. https://www.moh.gov.sa/HealthAwareness/EducationalContent/BabyHealth/Docu
ments/Intermediate%201%20Compatibility%20Mode.pdf
7. Linda S. Costanzo Physiology, sixth edition
8. Guyton and Hall Textbook of Medical Physiology, 13th ED.

43. Questions?

44. Thank You