1. Hydrocephalus

2. Hydrocephalus Not a specific disease
Represents a diverse group of conditions that result from impaired circulation and absorption of CSF
Hydrocephalus is not a specific disease; rather, it represents a diverse group of conditions that result from impaired circulation and absorption of CSF or, in the rare circumstance, from increased production by a choroid plexus papilloma ( Table ).

3. CSF Pathway
Normally, CSF flows from the lateral ventricles through the foramina of Monro into the 3rd ventricle. It then traverses the narrow aqueduct of Sylvius, which is ≈3 mm long and 2 mm in diameter in a child, to enter the 4th ventricle. The CSF exits the 4th ventricle through the paired lateral foramina of Luschka and the midline foramen of Magendie into the cisterns at the base of the brain
Hydrocephalus resulting from obstruction within the ventricular system is called obstructive or noncommunicating hydrocephalus. The CSF circulates from the basal cisterns posteriorly through the cistern system and over the convexities of the cerebral hemispheres. CSF is absorbed primarily by the arachnoid villi through tight junctions of their endothelium by the pressure forces that were noted earlier. CSF is absorbed to a much lesser extent by the lymphatic channels directed to the paranasal sinuses, along nerve root sleeves, and by the choroid plexus itself. Hydrocephalus resulting from obliteration of the subarachnoid cisterns or malfunction of the arachnoid villi is called nonobstructive or communicating hydrocephalus.

4. Hydrocephalus
Noncommunicating
Communicating

5. Noncommunicating Hydrocephalus
Obstructive
Hydrocephalus resulting from obstruction within the ventricular system
Aqueductal stenosis 
Infectious
X-linked
Chiari malformation
Dandy-Walker malformation
Klippel-Feil syndrome
Mass lesions
 Abscess 
Hematoma Tumors and neurocutaneous disorders 
Vein of Galen malformation 
Walker-Warburg syndrome
Hydrocephalus resulting from obstruction within the ventricular system is called obstructive or noncommunicating hydrocephalus. The CSF circulates from the basal cisterns posteriorly through the cistern system and over the convexities of the cerebral hemispheres. CSF is absorbed primarily by the arachnoid villi through tight junctions of their endothelium by the pressure forces that were noted earlier. CSF is absorbed to a much lesser extent by the lymphatic channels directed to the paranasal sinuses, along nerve root sleeves, and by the choroid plexus itself. Hydrocephalus resulting from obliteration of the subarachnoid cisterns or malfunction of the arachnoid villi is called nonobstructive or communicating hydrocephalus.

6. Communicating Hydrocephalus
Nonobstructive
Hydrocephalus resulting from obliteration of the subarachnoid cisterns of malfunctoin of the arachnoid villi
Achondroplasia
 Basilar impression
Benign enlargement of subarachnoid space
Choroid plexus papilloma
Meningeal malignancy
Meningitis
Posthemorrhagic
Hydrocephalus resulting from obliteration of the subarachnoid cisterns or malfunction of the arachnoid villi is called nonobstructive or communicating hydrocephalus.

7. Clinical Features of HCP
Variable, depends on many factors
Age at onset, nature of lesion causing obstruction, rate of increase of ICP
Infant
Rapidly enlarging head most prominent sign
Anterior fontanelle is wide open and bulging
Scalp veins dilated
Broad forehead
Setting-sun eye sign
Eyes deviated downward
Due to impingement of dilated suprapineal recess on the tectum
the age at onset, the nature of the lesion causing obstruction, and the duration and rate of increase of the intracranial pressure (ICP).
eyes may deviate downward because of impingement of the dilated suprapineal recess on the tectum

8. Clinical Features of HCP
Long-tract signs
Brisk tendon reflex
Spasticity
Clonus
Babinski
Long-tract signs including brisk tendon reflexes, spasticity, clonus (particularly in the lower extremities), and Babinski sign are common owing to stretching and disruption of the corticospinal fibers originating from the leg region of the motor cortex

9. Clinical Features of HCP
Older child
Cranial sutures partially closed
Signs of hcp subtler
Irritability
Lethargy
Poor appetite
Vomiting
Headache
Papilledema
Abducens nerve palsy
Pyramidal tract signs
Macewen sign
Percussion of skull  cracked pot sound
Indcateds separation of sutures
In an older child, the cranial sutures are partially closed so that the signs of hydrocephalus may be subtler. Irritability, lethargy, poor appetite, and vomiting are common to both age groups, and headache is a prominent symptom in older patients. A gradual change in personality and a deterioration in academic productivity suggest a slowly progressive form of hydrocephalus. Serial measurements of the head circumference indicate an increased velocity of growth. Percussion of the skull may produce a cracked pot sound or Macewen sign, indicating separation of the sutures. A foreshortened occiput suggests Chiari malformation, and a prominent occiput suggests the Dandy-Walker malformation. Papilledema, abducens nerve palsy, and pyramidal tract signs, which are most evident in the lower extremities, are apparent in most cases.
Papilledema, abducens nerve palsy, and pyramidal tract signs, which are most evident in the lower extremities, are apparent in most cases.

10. Clinical Features of HCP
Chiari malformation
Foreshortened occiput
Dandy-Walker malformation
Prominent occiput
A foreshortened occiput suggests Chiari malformation, and a prominent occiput suggests the Dandy-Walker malformation. Papilledema, abducens nerve palsy, and pyramidal tract signs, which are most evident in the lower extremities, are apparent in most cases.

11. Chiari Malformation Type I
Produces sx during adolescence or adult life
Usually not associated with hcp
Recurrent headache, neck pain, urinary frequency, progressive lower extremity spasticity
Consists of displacement of cerebellar tonsils into the cervical canal
Unknown pathogenesis
Type I typically produces symptoms during adolescence or adult life and is usually not associated with hydrocephalus. Patients complain of recurrent headache, neck pain, urinary frequency, and progressive lower extremity spasticity. The deformity consists of displacement of the cerebellar tonsils into the cervical canal ( Fig ). Although the pathogenesis is unknown, a prevailing theory suggests that obstruction of the caudal portion of the 4th ventricle during fetal development is responsible. Other theories include tethering of the cord or additional anomalies (syrinx).

12. Chiari Malformation Type II Progressive hcp with a myelomeningocele
Represesents an anomaly of the hindbrain due to failure of the pontine flexure during embryogenesis
Results in elongation of the 4th ventricle and kinking of brainstem
Displacement of inferior vermis, pons, medulla into the cervical canal
The type II Chiari malformation is characterized by progressive hydrocephalus with a myelomeningocele. This lesion represents an anomaly of the hindbrain, probably due to a failure of pontine flexure during embryogenesis, and results in elongation of the 4th ventricle and kinking of the brainstem, with displacement of the inferior vermis, pons, and medulla into the cervical canal ( Fig ). Approximately 10% of type II malformations produce symptoms during infancy, consisting of stridor, weak cry, and apnea, which may be relieved by shunting or by posterior fossa decompression. A more indolent form consists of abnormalities of gait, spasticity, and increasing incoordination during childhood. Plain skull radiographs show a small posterior fossa and a widened cervical canal. CT scanning with contrast and MRI display the cerebellar tonsils protruding downward into the cervical canal and the hindbrain abnormalities. The anomaly is treated by surgical decompression.

13. Chiari Malformation 10% produce sx during infancy Stridor Weak cry
apnea
Approximately 10% of type II malformations produce symptoms during infancy, consisting of stridor, weak cry, and apnea, which may be relieved by shunting or by posterior fossa decompression. A more indolent form consists of abnormalities of gait, spasticity, and increasing incoordination during childhood. Plain skull radiographs show a small posterior fossa and a widened cervical canal. CT scanning with contrast and MRI display the cerebellar tonsils protruding downward into the cervical canal and the hindbrain abnormalities. The anomaly is treated by surgical decompression.

14. Dandy-Walker Malformation
Consists of a cystic expansion of the 4th ventricle in the posterior fossa and midline cerebellar hypoplasia
Results from a developmental failure of the roof of the 4th ventricle during embryogenesis
90% have hcp
Associated anomalies
Agenesis of the posterior cerebellar vermis and corpus callosum
Infants present with a rapid increase in head size + prominent occiput
The Dandy-Walker malformation consists of a cystic expansion of the 4th ventricle in the posterior fossa and midline cerebellar hypoplasia, which results from a developmental failure of the roof of the 4th ventricle during embryogenesis ( Fig ). Approximately 90% of patients have hydrocephalus, and a significant number of children have associated anomalies, including agenesis of the posterior cerebellar vermis and corpus callosum. Infants present with a rapid increase in head size and a prominent occiput. Transillumination of the skull may be positive. Most children have evidence of long-tract signs, cerebellar ataxia, and delayed motor and cognitive milestones, probably due to the associated structural anomalies. The Dandy-Walker malformation is managed by shunting the cystic cavity (and on occasion the ventricles as well) in the presence of hydrocephalus.

15. Dandy-Walker Malformation
(+) skull transillumination
Long-tract signs
Cerebellar ataxia
Delayed motor and cognitive milestones
Most children have evidence of long-tract signs, cerebellar ataxia, and delayed motor and cognitive milestones, probably due to the associated structural anomalies. The Dandy-Walker malformation is managed by shunting the cystic cavity (and on occasion the ventricles as well) in the presence of hydrocephalus.

16. Baby Girl Mendoza
CT scan results