Hydrocephalus Definition -hydrocephalus Is The Abnormal Rise In Cerebrospinal Fluid

HYDROCEPHALUS Definition -Hydrocephalus is the abnormal rise in cerebrospinal fluid volume with ventricular dilatation due to imbalance of cerebrospinal fluid production and absorption. It is usually accompanied by increased intracranial pressure. Hydrocephalus is a diverse group of conditions, which result from; 1) Impaired circulation of CSF 2) Impaired absorption of CSF 3) In the rare circumstance, from increased production by a choroid plexus papilloma The most common causes of hydrocephalus in acquired cases are tumor obstruction, trauma, intracranial hemorrhage, and infection. Pathophysiology Flow of CSF CSF is produced in the lateral ventricle choroid plexus at 30mL/hr (20mL/hr in infants) Foramen of Monro ↓ 3rd Ventricle Cerebral aqueduct of sylvius ↓ 4th Ventricle Foramen of Lushka(2-lateral)↓ magendie foramen Subarachnoid basal cisterns posteriorly over the cerebellum and cerebral cortex, and anteriorly through the cistern system and over the convexities of the cerebral hemispheres. arachnoid granulations ↓ superior sagittal sinus ↓ Venous circulation

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These openings lead to a system of interconnecting and focally enlarged areas of subarachnoid spaces referred to as cisterns. The cisterns in the posterior fossa connect through pathways that traverse the tentorium to the subarachnoid spaces over the cerebral convexities. The spinal subarachnoid space communicates with the intracranial subarachnoid space by the basal cisterns

NB. Main CSF production is from the lateral ventricles ,some from the 4th ventricle. 25% CSF is produced from the ependymal lining of the ventricles. Infants –volume of CSF 50mls Adults – volume of CSF 125-150mls. Daily production of CSF 30ml/hr up to 720 ml/day TYPES OF HYDROCEPHALUS a) Obstructive / Non-communicating hydrocephalus Hydrocephalus resulting from obstruction within the ventricular system .Proximal dilatation from obstruction.

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In noncommunicating hydrocephalus the ventricular fluid does not communicate with CSF in the spinal subarachnoid spaces or in the basal cisterns. This implies a block of CSF flow within the ventricular system, such as at the foramen of Monro, the aqueduct of Sylvius, or the fourth ventricle and its outlets.

1. An abnormality of the Aqueduct: Stenosis; Congenital - inherited as a sex-linked recessive trait ,Acquired in Neurofibromatosis Gliosis; Intrauterine viral infections, SAH in a premature infant, Neonatal meningitis,Mumps meningoencephalitis 2.Lesions in the fourth ventricle: JUDY WAWIRA GICHOYA yr 2007

Chiari malformation  Type II is characterized by progressive hydrocephalus and a myelomeningocele which results in elongation of the fourth ventricle and kinking of the brain stem, with displacement of the inferior vermis, pons, and medulla into the cervical canal.  Produce symptoms during infancy consisting of stridor, weak cry, and apnea, which may be relieved by shunting or by posterior fossa decompression.  Type I produces symptoms during adolescence or adult life and is usually not associated with hydrocephalus.  These patients complain of recurrent headache, neck pain, urinary frequency, and progressive lower extremity spasticity. The deformity consists of tonsilar herniation. Dandy-Walker syndrome  Consists of a cystic expansion of the fourth ventricle in the posterior fossa, which results from a developmental failure of the roof of the 4th ventricle during embryogenesis.  Posterior fossa brain tumors- Meduloblastomas, hemangiomas, epindymomas. 3.Space occupying lesions may obstruct the flow along anyway along the ventricular system-Tumors, bleeds etc b) Non-obstructive / Communicating hydrocephalus Hydrocephalus resulting from obliteration of the subarachnoid cisterns or malfunction of the arachnoid granulations.

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In communicating hydrocephalus, the block is outside the ventricular system, and fluid within the ventricles communicates with the spinal subarachnoid space and basal cisterns.

1.Infections; -Intrauterine infections may destroy the CSF pathways. ---Pneumococcal and TB meningitis have a propensity to produce a thick, tenacious exudate that obstructs the basal cisterns 2.SAH Blood in the subarachnoid spaces may cause obliteration of the cisterns or arachnoid villi, and obstruction of CSF flow. 3.Leukemic infiltrates May seed the subarachnoid space and produce communicating hydrocephalus 4. Superior saggital sinus thrombosis This impairs venous drainage and impairs re-absorption through the arachnoid villi. 5. Overproduction of CSF-choroid plexus papilloma c) Normal-Pressure Hydrocephalus Cerebral ventricular dilation with normal lumbar CSF pressure (5-18cmH2O) Aetiology – Same as Non-Obstructive or communicating hydrocephalus above Presentation- Triad of normal pressure hydrocephalus. -Dementia - rare cause of dementia in the elderly -Apraxia of gait - initiation of gait is hesitant - described as a "slipping clutch" or "feet stuck to the floor" gait - and walking eventually occurs. Motor weakness and staggering are absent -Urinary incontinence Investigations CSF pressure is normal CT/MRI - the ventricles are dilated Mx; Shunting - Brief improvement after removing about 50mL of CSF indicates a better prognosis with shunting but the longer

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the disease has been present, the less likely shunting will be curative d)Ex Vacuo Hydrocephalus Enlarged ventricles resulting from a loss of brain tissue Other terms -Arrested hydrocephalus-the ventricles dilated but the pressures not increasing. Seen more in children -Occult hydrocephalus-dilated ventricles but no signs of raised ICP or suggestive of hydrocephalus. Composition of CSF-Clear fluid,15-45 mg/ml of protein -60-80mg/ml of glucose,3 lymphocytes or fewer Presenting complaints Infants; sutures still open History 1.Accelerated rate of enlargement of the head is the most prominent sign 2.Irritability, lethargy, poor appetite, and vomiting 3.Delayed milestones 4-Failure to thrive 5.Family history 6.Premature delivery 7.Previous history of treatment for meningitis 8.Maternal infections and drug intake in prenatal period. Physical examination 1. Enlarged head for the age. At birth head circumference is 35cm +/- 2cm.this increases by: 2cm per month for first 3 months  1cm per month next 3 months  ½ cm per month for next 6months  ¼ cm per month from 1year to 3 years old.  The occipitofrontal head circumference is recorded and kept for monitoring the head progression. 2-Scalp veins are dilated and congested 3-The forehead is broad 4-Anterior fontanel is wide open and bulging 5-Percussion of the skull may produce a "cracked-pot" or Macewen sign, indicating separation of the sutures 6-Craniotabes 7-A foreshortened occiput suggests the Chiari malformation, and a prominent occiput suggests the Dandy-Walker malformation. 8-Dilatation of the 3rd ventricle → dilatation of the suprapineal recess which then impinges on the tectum → eyes deviate downward - "setting-sun" eye sign.

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Upward gaze may be impaired because of pressure on the midbrain, and the sclera above the iris will be visible. This is known as the setting-sun sign. Also lid lag 9.Long tract signs-due to stretching and compression of corticospinal tract eg brisk tendon reflexes, spasticity, clonus in lower extremities, babinski reflex up going − Spasticity in the extremities, especially the legs, may develop as the fibers from the cortical motor areas are stretched around the bodies of the dilated ventricles in their course to the cerebral peduncles. 10. Transillumination of the skull is positive with massive dilatation of the ventricular system or in the Dandy-Walker syndrome. 11.Fundoscopy-Papilloedema is observed in older children but is rarely present in infants because the cranial sutures separate as a result of the increased pressure -In the older child, the cranial sutures are partially closed so that the signs of hydrocephalus may be more subtle. The signs of increased ICP become more prominent. − Disturbances in growth, accelerated pubertal development, and fluid and electrolyte homeostasis may develop from JUDY WAWIRA GICHOYA yr 2007

pressure exerted on the hypothalamus by the dilated third ventricle. DDx The head may appear enlarged secondary to a thickened cranium resulting from; 1) Familial-autosomal dominant 2) Chronic anemia eg Haemoglobinopathies, SCD, Thalassaemia 3) Rickets 4) Achondroplasia 5) Osteogenesis imperfecta 6) Epiphyseal dysplasia 7) Neurofibromatosis 8) Storage diseases-Gaucher’s disease, Tay sachs disease. Investigations in infants 1.Skull X-ray – Not very revealing but may show -Separation of the sutures -Erosion of the posterior clinoids in the older child -Increase in convolutional markings ("beaten-silver appearance") with longstanding increased intracranial pressure. -Flattening of gyri and obliteration of sulci -Herniations-tentorial and through foramen magnum 2.Ultrasonography Through the open anterior fontanele. 3.CT-scan Show ventricular dilatation 4.MRI Adults Clinical presentation Mainly signs of increased intracranial pressure. Signs /Symptoms of increased ICP Symptoms 1) -Severe bursting headache 2) -Projectile vomiting 3) -Blurring of vision 4) -Convulsions/seizures 5) –Drowsiness and altered consciousness. Signs 1) -Vital signs-increased BP and decreased pulse rate (cushings reflex) 2) -Anisocoria-unequal pupils 3) -Papilloedema on fundoscopy 4) -Nerve palsy eg 3rd and 6th cranial nerves 5) -Irregular breathing/slowed fats MANAGEMENT Aims 1. Reduce the intracranial pressure-Medical treatment or CSF diversion 2.Remove the underlying cause-Definitive surgery Medical treatment - When patients have slowly progressive hydrocephalus with few symptoms or signs, and when the condition of the patient has prohibited surgery. -Medical therapy usually is a temporizing measure. In transient conditions, such as sinus occlusion, meningitis, or neonatal intraventricular hemorrhage, medical therapy can be effective. - Acetazolamide (25 mg/kg/d in 3 doses): Careful monitoring of respiratory status and electrolytes is crucial. Treatment beyond 6 months is not recommended. - Furosemide (1 mg/kg/d in 3 doses): Again, electrolyte balance and fluid balance need to be monitored carefully. - Lumbar punctures: In neonates recovering from intraventricular hemorrhage, serial lumbar punctures can

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resolve hydrocephalus in some cases. If possible, this is the preferred method of treatment. - Removal of the underlying cause resolves hydrocephalus in most cases SURGERY CSF DIVERSION Short-term(temporary) -Acute intraventricular bleeds, subarachnoid bleeds, infections. There is high protein concentration in the CSF which would cause coagulum and block the valve. -Do external ventricular drains until blood is cleared from the CSF. And the infection has settled. -Exteriorization of the shunt can also be used for the administration of antibodies.

-Depend on the cause of the dilated ventricles and not on the size of the cortical mantle at the time of the shunting.  Increased risk of developmental problems  Mean intelligence quotient is reduced compared to general population  Risk of aggressive and delinquent behaviour  Accelerated pubertal development in patients with shunted hydrocepahalus or meningomyelocele due to increased gonadotropins due to increased ICP

Permanent CSF diversion 1.Ventriculoperitoneal shunt 2.Ventriculo-artrial Shunt 3.Ventriculopleaural shunt Ventriculoperitoneal shunt A shunt is placed from the lateral ventricle to the peritoneum Procedure -Standard pre-operative preparation -Patient in supine position -Clean and drape the right parietal, neck, chest and abdomen. Right side of the head to be away from the speech areasBrocas and Wernickes left in most people. -Do right parietal burr hole -Right subcostal minilaparatomy -Subcuticular tunneling -Insertion of the shunt system. -Cannulation of lateral ventricle and confirm that the shunt is functioning -Standard wound closure. Complications; 1-Bacterial infection, usually due to Staphylococcus epidermidis Other organisms found less frequently include S. aureus, enteric bacteria, diphtheroids, and Streptococcus species. Infection must be suspected in any child with a shunt who develops an unusual or persistent febrile illness. 2-Shunt blockade-mechanical kinks, choroid plexus block, omentum 3-Shunt disconnection-from the drainage of the lateral ventricle. 4-Shunt migration-can migrate downward the peritoneum 5-Subdural bleed due to rapid decompression seen with patients who have had sutural closure. Another complication of ventriculoatrial shunts is pulmonary hypertension owing to chronic microembolism from thrombi formed on the atrial catheter.

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Recently, third ventriculostomies (Establishment of an opening in a ventricle, usually through the floor of the third ventricle to the subarachnoid space to relieve hydrocephalus) have been used to treat some forms of hydrocephalus and have been performed instead of shunt revisions. Young infants are often not candidates for this procedure. If the shunt system becomes disconnected or the catheters become obstructed, symptoms will recur if the hydrocephalus is still active.

DEFINITIVE SURGERY -Operation for tumors -Appropriate craniotomy dependent on the location of the tumor. Prognosis

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