Cerebrospinal Fluid Disorders PDF

# Cerebrospinal Fluid Disorders ## Cerebrospinal Fluid (CSF) - CSF fills ventricles and subarachnoid space. - Volume = 150 ml - Rate of CSF formation = 21 to 22ml/h approx. 500ml/day so it turns 4 or 5 times/day. - Lumbar CSF pressure = 70-180 mm CSF - Absorption of CSF occurs by bulk flow is pro...

# Cerebrospinal Fluid Disorders ## Cerebrospinal Fluid (CSF) - CSF fills ventricles and subarachnoid space. - Volume = 150 ml - Rate of CSF formation = 21 to 22ml/h approx. 500ml/day so it turns 4 or 5 times/day. - Lumbar CSF pressure = 70-180 mm CSF - Absorption of CSF occurs by bulk flow is proportionate to CSF pressure. - At pressure of 112 mm (normal average): filtration and absorption are equal. - Below pressure of 68 mm CSF, absorption stops. ## Cerebrospinal Fluid Formation - CSF is largely formed by the choroid plexus of the lateral ventricle and remainder in the third and fourth ventricles. - About 30% of the CSF is also formed from the ependymal cells lining the ventricles and other brain capillaries. - The choroid plexus of the ventricles actively secrete cerebrospinal fluid. - The choroid plexuses are highly vascular tufts covered by ependyma. ## Formation & Circulation of CSF The image shows a schematic of the brain with the choroid plexus of the lateral ventricle, the third ventricle, the fourth ventricle, and the subarachnoid space. It shows the flow of CSF from the choroid plexus, through the ventricles, and into the subarachnoid space. ## Mechanism of Formation of CSF - CSF is formed primarily by secretion and also by filtration from the net works of capillaries and ependymal cells in the ventricles called choroid plexus. - Various components of the choroid plexus from a blood-cerebrospinal fluid barrier that permits certain substances to enter the fluid, but prohibits others. - Such a barrier protects the brain and spinal cord from harmful substances. - The entire cerebral cavity enclosing the brain and spinal cord has a capacity of about 1600 to 1700 milliliters - About 150 milliliters of this capacity is occupied by cerebrospinal fluid and the remainder by the brain and cord. - **Rate of formation:** - About 20-25 ml/hour - 500 ml/day in adults. Turns over 4 to 5 times a day - **Total quantity:** 150 ml - 30-40 ml within the ventricles - About 110-120 ml in the subarachnoid space [of which 75-80 ml in spinal part and 25-30 ml in the cranial part]. ## Mechanism of Formation - CSF is formed at a rate of about 500-550 milliliters each day. About two thirds or more of this fluid originates as secretion from the choroid plexuses in the four ventricles, mainly in the two lateral ventricles. - Additional small amount of fluid is secreted by the ependymal surfaces of all the ventricles and by the arachnoidal membranes - Small quantity comes from the brain itself through the perivascular spaces that surround the blood vessels passing through the brain. ## Secretion by the Choroid Plexus - The choroid plexus is a cauliflower-like growth of blood vessels covered by a thin layer of epithelial cells. - Secretion of fluid by the choroid plexus 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 because the positive charge of the sodium ion attracts the chloride ion's negative charge. The two of these together increase the quantity of osmotically active sodium chloride in the cerebrospinal fluid, which then causes almost immediate osmosis of water through the membrane, thus providing the fluid secretion. ## Mechanism of Formation - Less important transport processes move small amount of glucose into the cerebrospinal fluid and both potassium and bicarbonate ions out of the cerebrospinal fluid into the capillaries. The resulting characteristics of the CSF are: - Osmotic pressure approximately equal to that of plasma sodium ion concentration - Approximately equal to that of plasma chloride ion - About 15 per cent greater than in plasma potassium ion - approximately 40 per cent less glucose ## Absorption of CSF Through Arachnoid Villi - The arachnoidal villi are fingerlike inward projections of the arachnoidal membrane through the walls into venous sinuses. - Villi form arachnoidal granulations can protruding into the sinuses. - The endothelial cells covering the villi have vesicular passages directly through the bodies of the cells large enough to allow relatively free flow of (1) cerebrospinal fluid, (2) dissolved protein molecules, and (3) even particles as large as red and white blood cells into the venous blood. ## Composition of CSF | Constituent | Concentration | |---|---| | Proteins | 20-40 mg/100 ml | | Glucose | 50-65 mg/100 ml | | Cholesterol | 0.2 mg/100 ml | | Na+ | 147 meq/Kg H2O | | Ca+ | 2.3 meq/kg H2O | | Urea | 12.0 mg/100 ml | | Creatinine | 1.5 mg/100 ml | | Lactic acid | 18.0 mg/100 ml | ## Characteristics of CSF | Characteristic | Value | |---|---| | Colour | Clear, transparent fluid | | Specific gravity | 1.004-1.007 | | Reaction | Alkaline and does not coagulate | | Cells | 0-3/cmm | | Pressure | 60-150 mm of H₂O | - The pressure of CSF is increased in standing, coughing, sneezing, crying, compression of internal Jugular vein (Queckenstedt's sign ## Circulation of CSF - **Circulation:** CSF slowly moves cerebromedullary cistern and pontine cisterns and flows superiorly through the interval in the tentorium cerebelli to reach the inferior surface of the cerebrum. It moves superiority over the lateral aspect of each cerebral hemisphere. - **Pathway:** - Lateral ventricle - Foramen of Monro [Interventricular foramen] - Third ventricle: - Cerebral aqueduct - Fourth ventricle: - Foramen of megendie and formen of luschka - Subarachnoid space of Brain and Spinal cord ## Disturbance in the flow of the Cerebrospinal fluid - The image shows a schematic of the brain with the ventricles and subarachnoid space. It shows the flow of CSF from the ventricles to the subarachnoid space. It also shows how a blockage in the flow of CSF can lead to hydrocephalus. ## Cerebrospinal-fluid-formation-and-circulation-in-the-brain The image shows a diagram of the brain and spinal cord, with the flow of cerebrospinal fluid from the ventricles to the subarachnoid space. ## Functions of CSF - A shock absorber - A mechanical buffer - Act as cushion between the brain and cranium - Act as a reservoir and regulates the contents of the cranium - Serves as a medium for nutritional exchange in CNS - Transport hormones and hormone releasing factors - Removes the metabolic waste products through absorption ## Functions of the CSF 1. **Protective function:** The brain is supported within the arachnoid by the blood vessels, nerve roots, and the arachnoid trabiculae. In air brain weight =1400 g, but in its water bath of CSF, brain weight = 50 g, making it suspended effectively. When the head receives a blow, the arachnoid slides on the dura, and the brain moves, but its motion is gently checked by the CSF cushion and by the arachnoid trabiculae. Removal of CSF during lumbar puncture can cause severe headache 2. **Facilitation of pulsatile cerebral blood flow** 3. **Distribution of peptides, hormones,** **neuroendocrine factors** **and other nutrients and essential substances to cells of the body.** 4. **Wash away waste products.** 5. **Cardiovascular dynamics are also affected by CSF pressure, as the flow of blood must be tightly regulated within the brain to assure consistent brain oxygenation.** ## Blood brain Barrier (BBB) - It is formed by the tight junctions between capillary endothelial cells of the brain and between epithelial cells in the choroid plexus. This effectively prevents proteins from entering the brain in adults and slow the penetration of smaller molecules. - **Mechanisms of transport:** - Bulk flow - Carrier mediated transfer - Vesicular transport. ## Penetration of substances into the brain - **Molecules pass easily:** H₂O, CO₂, O₂, lipid-soluble free forms of steroid hormones. - **Molecules not pass:** proteins, polypeptides. - **Slow penetration:** H⁺, HCO₃^- - **Glucose:** its passive penetration is slow, but is transported across brain capillaries by GLUT1 ## Functions of BBB - Maintanins the constancy of the environment of the neurons in the CNS. - Protection of the brain from endogenous and exogenous toxins. - Prevent escape of the neurotransmitters into the general circulation. ## Development of BBB - Premature infants with hyperbilirubinemia, free bilirubin pass BBB, and may stain basal ganglia causing damage (Kernicterus). ## Clinical implications - Some drugs penetrate BBB with difficulty e.g. antibiotics and dopamine. - BBB breaks down in areas of infection, injury, tumors, sudden increase in blood pressure, and I.V injection of hypertonic fluids. - Injection of radiolabeled materials help diagnose tumors as BBB is broken down at tumor site because of increased vascularity by abnormal vessels. ## Circumventricular organs - Posterior pituitary - Area postrema - Organum vasculosum of the lamina terminalis (OVLT) - Subfornical organ (SFO) These areas are outside the blood brain barrier. They have fenestrated capillaries. - **Functions:** - Chemoreceptor trigger zone: As area postrema that trigger vomiting & cardiovascular control. - Ang II acts on SFO and OVLT to increase H₂O intake. - IL2 induce fever by (+) circumventricular organs. ## Circumventricular organs - The image shows a schematic of the brain with the circumventricular organs highlighted. ## What is ICP? - the pressure within the cranium that is exerted by the combined total volume of the 3 components within the skull The image shows a Venn diagram with 3 circles that overlap. The circles represent brain tissue, blood, and CSF. The overlapping areas represent the combined volume of the 3 components. ## Monroe-Kellie Doctrine - Brain tissue, blood volume and CSF volumes are in a state of dynamic equilibrium - If an increase occurs in any of the above, the volume of one or more of the other components must decrease or an elevation of ICP will result The image shows a scale with 3 weights representing brain tissue, blood, and CSF. The scale is balanced, representing the state of dynamic equilibrium. ## Elevated ICP - ICP can become elevated for various reasons in response to disease, environment, emotion, and normal bodily functions - Factors can be non-pathologic or pathologic in nature - These can cause slow elevations or rapid increases in ICP ## Elevated ICP Non-pathological causes include: - Coughing - Sneezing - Lifting - Bending - Valsalva (bearing down) - Stress - Blood pressure changes - Emotional responses - Body positioning ## Elevated ICP Pathological causes include: - Concussion - Contusion - Subdural Hematoma - Epidural Hematoma - Subarachnoid Hemorrhage - Hydrocephalus - Tumour - Edema - Abscess or Infection ## Elevated ICP Primary factors that influence elevated ICP include: - Blood pressure - Heart function - Intra-abdominal/Intrathoracic - Temperature - Pain - Carbon Dioxide/Acidosis - Hypoxia ## Why is it Important? - Maintaining cerebral perfusion pressure is the main focus in management of cerebral injuries that impact the 3 components in the central system- brain/blood/CSF - CPP is calculated using the Mean Arterial Pressure (MAP) and Intracranial Pressure (ICP) - CPP = MAP - ICP - What if you don't know the ICP? ## Why is it Important? - Normal CPP, 60 to 100 mmHg - Goal is to maintain a minimum of 60mmHg for brain injuries Cerebral Perfusion Pressure (CPP) values of: - >150 disrupts the blood brain barrier and causes hyperperfusion and potentially brain edema / swelling. This could potentially lead to herniation syndrome - <50 causes hypo perfusion and brain ischemia - <30 causes irreversible ischemia/ damage ## S & S of Increased ICP Depend On...... - Compartmental location of lesion (supratentorial or infratentorial) - Specific location of mass (cerebral hemispheres, brain stem or cerebellum) - Degree of intracranial compensation (compliance) The image shows a cross-section of the brain with the tentorium cerebelli and falx cerebri highlighted. ## S+S of Increasing ICP | Category | Symptoms | |---|---| | Patient Presentation | - LOC (subtle) <br>- Motor function <br>- Restlessness <br>- Nausea & vomiting <br>- Sensory deficits <br>- Headache <br>- Visual changes <br>- Seizures <br>- Pupil changes | | Vital Signs | - Elevated BP with no obvious cause <br>- Rising systolic pressure <br>- Widening pulse pressure <br>- Bradycardia | ## Cushing's Triad 1. HYPERTENSION - Pulse Pressure Widens 2. BRADYCARDIA 3. IRREGULAR RESPIRATIONS .....Late Signs ## Consequences of Prolonged Elevated ICP - Cerebral ischemia and stroke - Irreversible brain damage and cerebral hypoxia - Permanent physical disability - Brain herniation and brain death The image shows 2 stick figures, one with decerebrate rigidity (extension posturing) and one with decorticate rigidity (abnormal flexion). ## PATHOLOGY: - Hydrocephalus: 1. External hydrocephalus: Large amounts of CSF accumulates when the reabsorptive capacity of arachnoid villi decreases. 1. Internal hydrocephalus: occurs when foramina of Luschka & Magendie are blocked or obstruction within ventricular system, resulting in distention of the ventricles. ## Pathology: - **Acute obstruction:** - 1- causes increased pressure and rapid enlargement of the ventricular system. The frontal and occipital horns of the lateral ventricles enlarge first. Symmetric dilatation of the remainder of the intracerebral CSF-containing spaces follows. - 2- Iflattening of the gyri and compression of the sulci against the cranium, - 3- obliterating the subarachnoid space over the hemispheres. - 4- The vascular system is compressed, and the venous pressure in the dural sinuses increases. - 5-. contributes to the development of interstitial edema of the periventricular white matter. - 6- Another compensatory mechanism that limits expansion of the ventricular system in infants is spreading of the cranial sutures. - **chronic hydrocephalus** - the force of the fluid is distributed over the greater surface area of the enlarged ventricular system ## Etiology : - **Congenital :** - A - Neural tube defect: e.g myelomeningocele has the following - 1- obstruction of fourth ventricular outflow - 2- flow of CSF through the posterior fossa due to the Chiari malformation - 3- aqueductal stenosis. - B- Isolated hydrocephalus : - aqueductal stenosis in wich this stenosis may due to malformation or inflamation. - c- X-linked hydrocephalus : - aqueductal stenosis - D- CNS malformation : - 1- Chiari Il portions of the brainstem and cerebellum are displaced caudally into the cervical spinal canal. This obstructs the flow of CSF in the posterior fossa - 2- Dandy Walker syndrome : atresia of the foramine of Luschka and Magendie - 3- Vein of Galen malformation: compression of the cerebral aqueduct. ## Etiology : continued - **Congenital continued":"** - E- Intrauterine infection . rubella, cytomegalovirus, toxoplasmosis, and syphilis - F- Syndromi Hydrocephalus : 13,18,9 - **Acquired :** - 1 - Infection e.g. meningites and encephalities . - 2- Tumor : especially posterior fossa medulloblastomas, astrocytomas, and ependymomas. - 3- hemorrhage : - a- subarachnoid space - b- into the ventricular system ## Etiology: others - Ependymal and meningeal diseases - Regional arachnoiditis - Pachymeningitis - Superficial siderosis of the meninges - Oculoleptomeningeal amyloidosis ## Symptoms: | Category | Symptoms | |---|---| | Symptoms in children | - Slowing of mental capacity <br>- Headaches (initially in the morning) that are more significant than in infants because of skull rigidity <br>- Neck pain suggesting tonsillar herniation <br>- Vomiting, more significant in the morning <br>- Blurred vision: This is a consequence of papilledema and later of optic atrophy <br>- Double vision: This is related to unilateral or bilateral sixth nerve palsy <br>- Stunted growth and sexual maturation from third ventricle dilatation: This can lead to obesity and to precocious puberty or delayed onset of puberty.(hypothalmous) <br>- Difficulty in walking secondary to spasticity: This affects the lower limbs preferentially because the periventricular pyramidal tract is stretched by the hydrocephalus. <br>- Drowsiness | | Symptoms in infants | - Poor feeding <br>- Irritability <br>- Reduced activity <br>- Vomiting | ## Diagnosis : - Serial head measurement. - The diagnosis is confirmed by neuroimaging - In a newborn, ultrasonography is the preferred technique due to mobility and has no radition. - Infant and children CT and MRI. - A lumbar puncture (LP) should be performed in case of meningities or encephalities . ## Differential Diagnosis : - Intracranial Hemorrhage - Intracranial Epidural Abscess - Epidural Hematoma - Subdural Empyema - Subdural Hematoma - Brainstem Gliomas - Meningioma - Pseudotumor Cerebri: Pediatric Perspective - Pituitary Tumors ## Management : - **Shunt:** - RT lateral ventricle to peritoneum. - The catheter is connected to a one-way valve system - **Complication :** - 1-Infection: Staphylococcus epidermidis, S. aureus, enteric bacteria, diphtheroids, and StreptocoCCUS species. - 2- malfunction. ## CSF AND INFLAMMATION - Increased inflammatory cells [pleocytosis] may be caused by infectious and noninfectious processes. - Polymorphonuclear pleocytosis indicates acute suppurative meningitis. - Mononuclear cells are seen in viral infections (meningoencephalitis, aseptic meningitis), syphilis, neuroborreliosis, tuberculous meningitis, multiple sclerosis, brain abscess, and brain tumors. ## CSF AND PROTEINS - Increased protein: CSF protein may rise to 500 mg/dl in bacterial meningitis. - A more moderate increase (150-200 mg/dl) occurs in inflammatory diseases of meninges (meningitis, encephalitis), intracranial tumors, subarachnoid hemorrhage, and cerebral infarction. - A more severe increase occurs in the Guillain-Barré syndrome and acoustic and spinal schwannoma. ## CSF AND PROTEINS - Multiple sclerosis: CSF protein is normal or mildly increased. - Increased IgG in CSF, but not in serum [IgG/albumin index normally 10:1]. - 90% of MS patients have oligoclonal IgG bands in the CSF. Oligoclonal bands occur in the CSF only not in the serum. - The CSF in MS often contains myelin fragments and myelin basic protein (MBP). - MBP can be detected by radioimmunoassay. MBP is not specific for MS. It can appear in any condition causing brain necrosis, including infarcts. ## CSF & LOW GLUCOSE - **Low glucose in CSF:** This condition is seen in suppurative tuberculosis - Fungal infections - Sarcoidosis - Meningeal dissemination of tumors. - Glucose is consumed by leukocytes and tumor cells. ## Leukemia Cells in CSF - The image shows a microscopic view of leukemia cells in CSF. ## CT Attenuation Pattern Normal Brain - The image shows 2 CT scans of the brain. The first image is a plain CT scan of the brain, and the second image is a CT scan of the brain with contrast. ## Gray matter or White matter involvement? - The image shows a CT scan of the brain with a large acute infarct. ## CT FINDINGS in SUBARACHNOID HEMORRHAGE - The image shows 2 CT scans of the brain, each with a subarachnoid hemorrhage highlighted with red arrows. ## Herniations The image shows a cross-section of the brain with 3 different types of herniations: - Subfalcine herniation - Uncinate herniation - Tonsiliar herniation - **Three well-known herniations:** - Subfalcial - Transtentorial - Cerebellar-foramen magnum - **Lessfamiliar:** - Upward cerebellar- tentorial - Diencephalic sella turcica - Orbital frontal-middle cranial fossa ## THANK YOU - The document is from a presentation about cerebrospinal fluid disorders.