HYDROCEPH ALUS NEIL BARRY 11/0537/1159 MEDICAL AND SURGICALCONDITIONS

Definition  Hydrocephalus is an abnormal expansion of cavities (ventricles) within the brain that is caused by the accumulation of cerebrospinal fluid. Hydrocephalus comes from two Greek words: hydros means water and cephalus means head.  There are two main varieties of hydrocephalus: congenital and acquired. An obstruction of the cerebral aqueduct (aqueductal stenosis) is the most frequent cause of congenital hydrocephalus. Acquired hydrocephalus may result from spina bifida, intraventricular hemorrhage, meningitis, head trauma, tumors, and cysts.

Definition of Adult Hydrocephalus  Ventricular enlargement due to altered CSF flow or resorption, with or without symptoms or neurologic impairment  Obstructive Hydrocephalus  Impairment of CSF flow within the ventricular system  Communicating Hydrocephalus  Impairment of CSF flow or resorption outside the ventricular system  Impaired flow through the subarachnoid space  Impaired resorption at the arachnoid granulations 3

Hydrocephalus  is the result of an imbalance between the formation and drainage of cerebrospinal fluid (CSF).  Approximately 500 milliliters (about a pint) of CSF is formed within the brain each day, by epidermal cells in structures collectively called the choroid plexus. These cells line chambers called ventricles that are located within the brain.  There are four ventricles in a human brain. Once formed, CSF usually circulates among all the ventricles before it is absorbed and returned to the circulatory system.  The normal adult volume of circulating CSF is 150 ml. The CSF turn-over rate is more than three times per day. Because production is independent of absorption, reduced absorption causes CSF to accumulate within the ventricles.

Obstructive Hydrocephalus: Aqueductal Stenosis  36-yo man with heada ches, syncop e, job impair ment 5

Communicating Hydrocephalus  Idiopathic  In the elderly, normal pressure hydrocephalus  Chronic, insidious onset  Symptomatic (secondary) hydrocephalus  Post-subarachnoid hemorrhage (aneurysm), post-infectious, post-traumatic  Acute, subacute or chronic onset 6

Normal Pressure Hydrocephalus  NPH is a treatable form of dementia, gait apraxia and urinary incontinence  Treatment is surgical--shunt insertion  Treatable nature of NPH distinguishes it from the essentially untreatable nature of most dementias  Common diagnostic tests do not predict the outcome from shunt surgery very well 7

NPH Diagnosis  NPH clinically overlaps with many conditions of the elderly  Vascular dementia  Degenerative dementias or disease  Cervical stenosis/myelopathy  Lumbar stenosis  Peripheral neuropathy 8

Aetiology  Hydrocephalus has a variety of causes including:  congenital brain defects  hemorrhage, either into the ventricles or the subarachnoid space  infection of the central nervous system (syphilis, herpes, meningitis, encephalitis, or mumps)  tumor

 Hydrocephalus that is congenital (present at birth) is thought to be caused by a complex interaction of genetic and environmental factors. Aqueductal stenosis, an obstruction of the cerebral aqueduct, is the most frequent cause of congenital hydrocephalus.

Signs and symptoms of elevated-pressure hydrocephalus include:  headache  nausea and vomiting, especially in the morning  lethargy  disturbances in walking (gait)  double vision  subtle difficulties in learning and memory  delay in children achieving developmental milestones

 Irritability is the most common sign of hydrocephalus in infants. If this is not treated, it may lead to lethargy. Bulging of the fontanelles, or the soft spots between the skull bones, may also be an early sign. When hydrocephalus occurs in infants, fusion of the skull bones is prevented. This leads to abnormal expansion of the skull.  Symptoms of normal pressure hydrocephalus include dementia, gait abnormalities, and incontinence (involuntary urination or bowel movements).

TREATMENT  The primary method of treatment for both elevated and normal pressure hydrocephalus is surgical installation of a shunt. A shunt is a tube connecting the ventricles of the brain to an alternative drainage site, usually the abdominal cavity. A shunt contains a one- way valve to prevent reverse flow of fluid. In some cases of non-communicating hydrocephalus, a direct connection can be made between one of the ventricles and the subarachnoid space, allowing drainage without a shunt.

Spina Bifida

 Spina bifida begins usually before the woman knows she is pregnant (day 21-28)  The tissues that form the neural tube do not close or stay completely closed.  An opening in the vertebrae that protect the spinal cord is formed.

Potential Causes  Homocysteine concentration in the bloodstream is increased  Homocysteine is a byproduct of Methionine  It can be reused to recreate Methionine  In acetaminophen poisoning, methionine prevents the breakdown products of acetaminophen from damaging the liver.

Potential Causes Cont’d  A family with one child that has spina bifida are 8 times more likely to have another with the disease  Genetic factors (heredity)  Environmental factors  Nutrition  Substance exposure  Decreased folic acid intake during pregnancy

Types and of Spina Bifida 1. Occulta “hidden” this type is covered by a layer of skin and is not visible outside the body, however the vertebrae are malformed. 2. Meningocele the spinal cord membrane bulges out of an opening that is caused by damaged or missing vertebrae and is usually seen as a cyst or bump covered by skin, the spinal cord develops normally 3. Myelomeningocele the spinal cord, nerves and membrane sticks out from the opening in the spine, usually breaking the skin causing spinal fluid leakage. After surgery, paralysis is still present.

Spina Bifida Complications  Degrees of spine exposure at birth can cause:  Paralysis  Need for surgery  Spine problems  More mild problems that require the use of crutches, wheelchair, or leg braces.  Can also be accompanied by learning problems, and difficulties with bowels and urination, as well as fluid on the brain

Treatment  Meningocele can be treated surgically to restore normal spinal cord function  Myelomeningocele spina bifida is operated on within 48 hours after birth to prevent severe bacterial infection. Surgeons place the spinal cord back in the canal and cover it with muscle and skin. Paralysis and bowel problems still persist after surgery.

Treatment  Initial surgery may be carried out during the first days of life, providing protection against injury and infection.  Subsequent surgery is often necessary to protect against excessive curvature of the spine, and in the presence of hydrocephaly, to place a mechanical shunt to decrease the pressure and amount of cerebrospinal fluid in the cavities of the brain.  Because of weakness or paralysis below the level of the spine abnormality, most children will require physical therapy, bracing, and other orthopedic assistance to enable them to walk. A variety of approaches including periodic bladder catheterization, surgical diversion of urine, and antibiotics are used to protect urinary function

Benefits Decrease handicaps Corrected brain malformations Risks Infection Blood loss Premature delivery Organ immaturity Death Fetal Surgery Treatment

References  a_p2.html a_p2.html      "Hydrocephalus." American Association of Neurological Surgeons/Congress of Neurological Surgeons. 〈 〉.  "Hydrocephalus." Institute for Neurology and Neurosurgery. Beth Israel Medical Center, New York, NY. 〈 m 〉.  "Hydrocephalus." National Library of Medicine. MEDLINEplus.