1. PEDIATRIC NEUROSURGERY DEVELOPMENTAL DISEASE
-HYDROCEPHALUS
-CRANIOSYNOCYTOSIS
-ENCEPHALOCELE

2. HYDROCEPHALUS
Increase in ventricular size due to an imbalance between the production of CSF and its drainage by the arachnoid villi.

3. Ventricles - CSF Ventricles are filled with cerebrospinal fluid (CSF)
The choroid plexuses are the source of approximately 80% of the CSF
The blood vessels in the subependymal regions, and pia also contribute to the formation of CSF

4. CSF has three important life-sustaining functions:
1) acting as a cushion or "shock absorber«
2) to act as the vehicle for delivering nutrients to the brain and removing waste
3) to flow between the cranium and spine and compensate for changes in intracranial blood volume (the amount of blood within the brain)

5. CSF Circulation
From the choroid plexus, the CSF flows to the lateral ventricle
interventricular foramen of Monro, the third ventricle
 the cerebral aqueduct of Sylvius, the fourth ventricle
the 2 lateral foramina of Luschka and 1 medial foramen of Magendie, the subarachnoid space
the arachnoid granulations, the dural sinus, and finally into the venous drainage.

7. Hydrocephalus Types
Communicating hydrocephalus occurs when the flow of CSF is blocked after it exits the ventricles. This form is called communicating because the CSF can still flow between the ventricles, which remain open
or Overproduction of CSF
Non-communicating hydrocephalus - also called "obstructive" hydrocephalus - occurs when the flow of CSF is blocked along one or more of the narrow passages connecting the ventricles.

8. COMMUNICATING HYDROCEPHALUS
Choroid plexus papillomas OVERPRODUCTION OF CSF
Subarachnoid and intraventricular bleeding,
Inflammatory conditions (meningitis)

9. NON-COMMUNICATING HYDROCEPHALUS
Tumors (benign and malignant),
Foraminal gliosis/stenosis,
Aqueductal stenosis/web/gliosis,
(most common cause of congenital hydrocephalus(43%))
Congenital anomalies (Chiari malformations, Dandy-Walker malformations,…)

10. Clinical manifestations
Clinical features of hydrocephalus are influenced by the following:
Patient's age
Cause
Location of obstruction
Duration
Rapidity of onset

11. Symptoms in infants include the following:
Poor feeding
Irritability
Reduced activity
Vomiting

12. Physical findings in infants include the following:
Head enlargement: Head circumference is at or above the 98 th percentile for age.
Sutures are seperated
Dilated scalp veins:
Tense fontanelle: bulging fontanelle first sign

13. Setting-sun sign: In infants, it is characteristic of increased intracranial pressure (ICP). Ocular globes are deviated downward, the upper lids are retracted, and the white sclerae may be visible above the iris.
Increased limb tone: Spasticity preferentially affects the lower limbs. The cause is stretching of the periventricular pyramidal tract fibers by hydrocephalus.

14. Symptoms in children include the following:
Slowing of mental capacity
Headaches (initially in the morning) that are more significant than in infants because of skull rigidity
Vomiting, more significant in the morning
Blurred vision:
Double vision: This is related to unilateral or bilateral sixth nerve palsy
Difficulty in walking secondary to spasticity: This affects the lower limbs preferentially because the periventricular pyramidal tract is stretched by the hydrocephalus.

15. Physical findings in children include the following:
Papilledema: if the raised ICP is not treated, this can lead to optic atrophy and vision loss.
Failure of upward gaze: This is due to pressure on the tectal plate through the suprapineal recess. The limitation of upward gaze is of supranuclear origin. When the pressure is severe, other elements of the dorsal midbrain syndrome (ie, Parinaud syndrome) may be observed, such as light-near dissociation, convergence-retraction nystagmus, and eyelid retraction (Collier sign).
Macewen sign: A "cracked pot" sound is noted on percussion of the head.
Unsteady gait: This is related to spasticity in the lower extremities.

16. Diagnostic Evaluation
Antenatal- fetal ultrasound as early as 14 weeks
Infancy- based on head circumference crosses one or more grid lines on the infant growth chart within a 4 week period and there are progressive neuro signs.
CT and MRI to localize site of obstruction; reveal large ventricles

17. Therapeutic management
Usually surgical treatment
Direct removal of source of obstruction (neoplasm, cyst, or hematoma)

18. Most require shunt procedure to drain CSF from ventricles to extracranial area; usually peritoneum(VP shunt), or right atrium (VA shunt) for absorption.

19. CRANIOSYNOCTOSIS
Craniosynostosis (kray-nee-o-sin-os-TOE-sis) is a birth defect in which one or more of the fibrous joints between the bones of your baby's skull (cranial sutures) close prematurely (fuse), before your baby's brain is fully formed. Brain growth continues, giving the head a misshapen appearance.

20. Types of craniosynostosis
 Most involve the fusion of a single cranial suture. Complex craniosynostosis involves the fusion of multiple sutures. Most cases of complex craniosynostosis are linked to genetic syndromes and are called syndromic craniosynostosis.

21. Scaphocephaly :Premature fusion of the sagittal suture is the most common craniosynostosis. The head typically is elongated in the anterior-posterior diameter and shortened in the biparietal diameter. Ridging of the sagittal suture is palpable.
Trigonocephaly :Premature fusion of the metopic suture frequently results in pointed forehead (ie, triangular shaped head)

22. Anterior plagiocephaly :Premature fusion of 1 coronal suture
Anterior plagiocephaly :Premature fusion of 1 coronal suture.  baby's forehead to flatten on the affected side and bulge on the unaffected side
Brachycephaly :Premature fusion of both coronal sutures results in increased biparietal diameter. This anomaly is often syndromic. The skull is shorter in the anterior-posterior diameter

23. Posterior plagiocephaly :lambdoid suture fusion (< 2%) or positional molding (vast majority)

24. The signs of craniosynostosis are usually noticeable at birth, but they'll become more apparent during the first few months of your baby's life. These can include:
A misshapen skull, with the shape depending on which of the sutures are affected
An abnormal feeling or disappearing fontanel on your baby's skull
Development of a raised, hard ridge along affected sutures
Slow or no growth of the head as your baby grows

25. Diagnosis
Physical exam. Your doctor will feel your baby's head for abnormalities such as suture ridges, and look for facial deformities.
Imaging studies. computerized tomography (CT)
Genetic testing. If your doctor suspects an underlying genetic syndrome, genetic testing may help identify the syndrome.

26. Treatment Mild cases molded helmet
However, for most babies, surgery is the primary treatment
The purpose of surgery is to correct the abnormal head shape, reduce or prevent pressure on the brain, create room for the brain to grow normally and improve your baby's appearance. This involves a process of planning and surgery.

27. Endoscopic surgery
babies up to age 6 months who have single-suture craniosynostosis.
Open surgery
for babies older than 6 months

28. ENCEPHALOCELE
 An encephalocele is a protrusion of the brain and/or meninges through a defect in the skull (cranium bifidum) that is “closed” or covered with skin. The condition is a rare form of Neural tube defect (NTD) that is observed at the time of birth.

29. Embriology
The central nervous system (CNS) appears as a plate of thickened ectoderm called the neural plate at the beginning of the third week of embryonic life. The lateral edges of the neural plate become elevated to form the neural folds and fuse to form the neural tube; the fusion begins in the cervical region and proceeds in both the rostral and caudal directions.The rostral neuropore closes on the 25th day after conception, and the caudal neuropore closes two days later. Neural tube defects (NTDs) result from failure of the neural tube closure between 25 and 27 days after conception.

30. Encephaloceles are divided into three major types:
●Sincipital (fronto-ethmoidal)
●Basal (trans-sphenoidal, spheno-ethmoidal, trans-ethmoidal, and spheno-orbital)
●Occipital  

31. Prevalence
Encephalocele is less common than other neural tube defects. Its prevalence has been estimated at 0.8 to 5 per 10,000 live births.
Occipital encephaloceles are the most frequent type in North America and Western Europe, where about 85 percent of encephaloceles take this form.On the other hand, in Southeast Asia, parts of Russia, and central Africa, anterior encephaloceles are more frequent.

32. Clinical Features
Sincipital (fronto-ethmoidal) encephaloceles may be occult lesions that are not noticeable or may present with marked craniofacial deformities (hypertelorism, orbital dystopia, or unilateral micro/anophthalmos).
Basal encephaloceles may or may not be apparent on external inspection, but there may be a broadened nasal bridge, hypertelorism, or other midfacial anomalies. Affected patients may present as a nasal or epipharyngeal mass, difficulty breathing, recurrent upper tract infections, nasal discharges, recurrent meningitis, or CSF leaks.

33. ●Occipital encephaloceles usually are obvious at the time of birth and many are diagnosed prenatally by ultrasonography. The neural tissue usually is covered by skin. Those of relatively large size may be associated with cranial nerve deficits, poor sucking and feeding, spasticity, blindness, seizures, or developmental delay. Neurologic deficits may progress after birth if hydrocephalus develops. Occipital encephalocele also may be associated with hind-brain anomaly (Chiari III malformation) in which herniating occipital/cerebellar tissues distort the posterior fossa structures . (See "Chiari malformations".)

34. DIAGNOSIS
The diagnosis is apparent at birth in most of the occipital encephaloceles. Basal encephaloceles may present as a midline mass in the nose or may not be visible. An encephalocele may be mistaken for a nasal polyp if it is located within the nose or for a soft tissue tumor if it is covered with skin and anterior to the nose

35. Imaging CT
MRI
Prenatal USG

36. Treatment
Surgical correction of the defect that develops in the skull of the neonates is the only technique to treat the condition. 
Generally, surgery is performed during infancy to place the protruding tissues back into the skull, remove the sac, and correct the associated craniofacial abnormalities. Even large protrusions can often be removed without causing major functional disability. Hydrocephalus associated with encephaloceles may require surgical treatment with a shunt. 

37. Prevention
Proper intake of folic acid in the first few weeks of pregnancy may reduce the occurrence of this form of NTD, even before becoming pregnant
400 micrograms of folic acid daily. 

38. References http://emedicine.medscape.com/article/1135286-overview
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