Production of CSF Net transport of Na+ and Cl- across the epithelium results in the secretion of CSF. Cl- efflux from the epithelium to CSF is mediated by a cotransporter. The generation of H+ and HCO3 by carbonic anhydrase is important in the secretion of CSF.
Function of CSF• Maintenance of a constant external environment for neurons and glia• Mechanical cushion to protect the brain and provide buoyancy to the heavy brain .• Serves as a lymphatic system and a conduit for neuropeptides• pH of CSF regulates pulmonary ventilation and CBF
Types of hydrocephalus• Obstructive hydrocephalus There is an obstruction in the flow of CSF within the normal pathway.• Communicating hydrocephalus There is no block in the flow of CSF, but the CSF is not absorbed properly back into the bloodstream• Normal pressure hydrocephalus Usually occurs in older age groups and is due to a lack of properly functioning brain structures.• Secondary hydrocephalus Usually results from an infection (such as meningitis) or a severe head injury.
CAUSES Congenital hydrocephalus TORCH INFECTIONS (e.g., cytomegalovirus [CMV], toxoplasmosis, rubella) congenital malformations1. Aqueductal stenosis–narrowing of the pathway to the fourth ventricle2. Arnold-Chiari malformations–small part of the cerebellum protrudes into the spinal canal3. Dandy-Walker syndrome–enlarged fourth ventricle due to obstruction in pathway4. Spina bifida–portion of the spinal cord is pushedthrough an abnormal opening between two vertebrae
CAUSES-Acquired hydrocephalus• IC Bleeding (hemorrhage)• Brain trauma (i.e., result of injury)• Brain tumor• Cyst (i.e., a fluid-filled sac)• Infection (e.g., cerebral abscess, bacterial meningitis
Signs in infants•An unusually large head•A rapid increase in the size of the head•A bulging frontenelle•Vomiting•Sleepiness•Irritability•Seizures•Eyes fixed downward (sunsetting of the eyes)•Developmental delay
older children, common signs and symptoms of hydrocephalus include:• Headache followed by vomiting• Nausea• Blurred or double vision• Eyes fixed downward (sunsetting of the eyes)• Problems with balance, coordination or gait• Slowing or regression of development• Memory loss• Confusion• Urinary incontinence• Irritability• Changes in personality
• The characteristic Hakims Triad may be seen in normal pressure hydrocephalus, which is found mostly in adults:• psychiatric disorders, mimicking the appearances of dementia• This involves mostly slow and poor quality ideation and activity, with apathy and indifference, serious memory and orientation disturbance, particularly in time, loss of attention and unawareness of reality.
• GAIT DISORDERS, with instability• This is due to static abnormalities, which may develop into titubation. The person moves around slowly and with care and may, occasionally, walk on the spot. Turning around, or either starting or stopping suddenly leads to imbalance.• SPHINCTER DISTURBANCE (incontinence++)• On occasions, the person is incontinent of urine and occasionally faeces. It is not clear whether this is due to inattention, reduced awareness or urgency of micturition. The patient may pass urine anywhere and soil his clothing.•
Assessment• Bulging fontanels• Split sutures• Increasing head circumference• Prominent scalp veins• Sunset eyes• Irritability• Poor feed• The older child will complain of headache
Palpation of fontanels• Anterior – diamond shaped, intersection of coronal and metopic sutures, FT 3-4cm by 1-3cm• Posterior – triangular shaped, intersection of sagittal and lambdoidal sutures, FT 1-3cm wide• Findings • normal- soft/flat • full, bulging • sunken
Palpation of sutures• Normally should feel slightly mobile when slight pressure is applied• Overriding• Separated• Craniosynostosis
Head circumference• Occipital-frontal circumference is measured with the tape placed just above the eyebrows.• Factors that can effect measurement: edema, IV infiltrates in scalp, cephalhematoma• Serial measurements over time give you the most useful information.
Head growth• Preterm: 0.5-1.0cm/week• Term: 0.5cm/week• Sick or preterm infants may have slowing of head growth with subsequent “catch up” after recovery.
Abnormalities of head size• Macrocephaly – >90th percentile for gestational age – potential causes: hydrocephaly, hydrencephaly
Head shape• Effects of labor and delivery – molding• Birth trauma – cephalhematoma – caput succedaneum• Craniosynostosis• Dolichocephaly of www.nlm.nih.gov prematurity
Auscultation of fontanel• Bell of stethoscope is placed over the fontanels and also may be placed over the temporal, frontal, and occipital areas.• Listening for bruits• Why? Bruits can be heard with arteriovenous malformations and aneurysms.
Increased ICP; vital signs1. CEREBRAL ISCHEMIA; CUSHING’S REFLEX2. SYSTEMIC VASOCONSTRICTION3. RESPONSE TO INCREASED BP IS TO SLOW HEART4. LOW CO2 FROM ACCELERATED CIRCULATION REDUCED RESPIRATORY RATE5. AS CIRCULATION TO BRAIN IMPROVES, RELIEVES ISCHEMIA, VASOCONSTRICTION RELAXED
Vital Sign Changes Increase in Blood Pressure Cushing TriadDecrease in Pulse Altered Respiratory pattern
Increased ICP; visual signsPRESSURE ON OCULOMOTOR NERVE (III) AFFECTS THE SIZE AND RESPONSE OF THE PUPILS.IPSILATERAL PUPIL BECOMES FIXED AND DILATED.
Diagnostic tests• x-ray - a diagnostic test which uses invisible electromagnetic energy beams to produce images of internal tissues, bones, and organs onto film.• computed tomography scan (Also called a CT or CAT scan.) - a diagnostic imaging procedure that uses a combination of x-rays and computer technology to produce cross-sectional images (often called slices),
Lumbar Puncture Insertion of spinal needle into subarachnoid space between the lower lumbar vertebrae. Waley & WongModified sitting position for LP
Cerebral Spinal Fluid• Normal CSF • Abnormal CSF• Clear odorless • Turbid, cloudy• WBC’s 0 – 5 • WBC’s 1000 – 2000• Protein 15 to 45 • Protein 100 – 500• Glucose 50 – 80 • Glucose lower than• Pressure 50 to 180 blood sugar • Pressure 180 or greater
Interventions • The shunt consists of three parts: 1. a tube that is placed inside of the ventricular space 2. a reservoir and valve to control the flow of CSF 3. tubing that is directed under the skin to the abdomen, or less commonly to the heart or lung area
Care of shunt• Frequently check for any redness or secretion on the skin over the shunt.• Check the integrity of the skin over the shunt, wounds or scratches may conduct to infection..• Check that the fontanel is leveled or depressed below the level of the bone.• Observe for symptoms of shunt malfunction.
complications from the shunts or surgery• infection• shunt malfunction that results in under- drainage or over-drainage of the CSF• bleeding