Pathology of the Nervous System - Quia



Pathology of the Nervous System

Stacy T Black BS, R.T. (R)

Meningitis

An acute inflammation of the pia mater, arachnoid, membranes covering the brain and spinal cord.

Infecting organisms can reach meninges through…

Middle ear

Upper respiratory tract

Frontal sinus infection

Bloodstream from infection from other site.

Bacterial Meningitis – Caused by Haemophilus in children/neonates, and by meningococcus / pneumococcus in adults and adolescents.

Meningitis cont..

Viral meningitis – Caused by mumps, poliovirus, and occasionally by herpes simplex.

**Bacterial is most common form (kissing, sharing toothbrush etc.)

Radiographic Appearance

CT / MRI good at visualizing inflammation.

Plain films can demonstrate osteomylitis, paranasal sinusitis, or skull fx as underlying cause of meningitis.

Treatment

Antiviral and antibiotic medications

Encephalitis

Viral inflammation of the brain and meninges. Symptoms range from mild headache to seizures and coma.

Many viruses and a few other microbes can cause encephalitis. Herpes simplex is the most common identifiable cause of encephalitis, but often the cause cannot be found at all.

several arboviruses (meaning viruses spread by insects) cause encephalitis. Vectors such as mosquitoes can transfer the virus to humans.

Encephalitis cont..

Radiographic appearance.

A mass effect is most common and may be seen as a midline shift or as a focal mass compressing ventricles or the sylvian cisterns.

Treatment

A definite diagnosis of herpes is essential before beginning treatment because must rule out it being a abscess or tumor.

Treated with antiviral drugs.

Brain Abscess

A localized infection of the brain cased by a microorganism affecting the grey and white matter. Usually a result of infections of the middle ear, paranasal sinuses, mastoid air cells, or systemic infections.

Brain abscess cont..

Radiographic appearance

MR and CT used to image an area of abnormal density with poorly defined borders and a mass effect reflecting vascular congestion and edema.

Plain films may show evidence of underlying sinusitis, mastoiditis, or osteomyelitis.

Treatment

Antibiotics or for severe cases craniotomy.

Subdural Empyema

Infection in the space between the inner surface of the dura and the outer surface of the arachnoid.

Makes up 25% of all intracranial infections

Most common cause is the spread of infection from the frontal and ethmoid sinuses

Subdural empyema cont..

Radiographic appearance

Fluid collection adjacent to the inner border of the skull with displacement of ventricular structures.

Treatment

Medical emergency. Immediate drainage of area and sinuses.

Epidural empyema

Infection outside the dural membrane and beneath the inner table of the skull.

Invariably associated with osteomylitis

Originates from an infection in the ear or paranasal sinuses.

Epidural empyema cont..

Radiographic appearance

Poorly defined area of low density adjacent to the inner table of the skull.

Treatment

Medical emergency. Immediate drainage of area and sinuses.

Osteomyelitis

Suppurative process from the paransal sinuses, mastiod air cells, and scalp.

Infection of the cranial bones due to nuero disorder that develops 1 to 2 weeks after the onset of signs and symptoms

Osteomyelitis cont..

Radiographic appearance

Multiple radiolucent areas of the skull. Attempts at bone regeneration produce multiple areas of poorly reactive sclerosis.

Treatment

Antibiotic and or surgery.

Tumors of the CNS

Neoplasms present with seizure disorders or gradual neurological deficits like thinking slow, weakness and or headaches.

50% are primary lesions with the other half metastases

Tumors cont.

Radiographic appearance

MRI modality of choice.

Treatment

Based on location, type and extent.

Surgery, chemo and radiation therapy are all choices and can be performed with each other.

Glioma

Most common primary malignant brain tumor that consist of glial cells that have the ability to multiply.

Spread by direct extension and can cross from one cerebral hemisphere to the other.

Gliomas cont..

Types

Glioblastomas – highly malignant lesions that are predominantly cerebral.

Astrocytomas – 70% of all gliomas. Slow growing tumors that have infiltrative characteristics and can form large cavaties.

Ependymoma

Medullablastoma

olgidendrocytoma

Glioma cont..

Radiographic appearance

Most commonly seen as a single, nonhomogeneous masses that may have edema.

Treatment

Surgery or radiation therapy

Meningioma

Benign tumor that arises from the arachnoid lining and attached itself to the dura.

Seizures and neurologic defects are most often caused by mass effect.

Radiographic appearance

Anatomic distortion. A thin rim of CSF may separate the tumor from the adjacent brain.

Treatment

Surgical resection

Pituitary Adenoma

Tumors that arise form the anterior lobe and constitute more than 10% of all intracranial tumors

Nonsecreting and hormone secreting type.

Effects the ACTH and TSH hormones

Adrenocorticotropic Hormone – stimulates the adrenal cortex to secrete cortisol.

Thyroid stimulating hormone - regulates the endocrine function of the thyroid gland.

Pituitary adenoma cont…

Can cause Cushing’s disease and hyperthyroidism.

Radiographic appearance

MRI modality of choice.

Lesion associated with contralateral deviation of the pituitary stalk and an upwardly convex contour of the gland.

Treatment

Surgery ; Radiation therapy

Metastatic

Carcinoma

Cancer that reaches the brain through hematogenous spread (spread through the bloodstream)

The most common neoplasms that metastasize to the brain arise in the lung and breast.

Metastatic carcinoma cont…

Radiographic appearance

Single or multiple masses situated at the junction between gray matter and white matter.

Treatment

Chemotherapy

Radiation therapy

surgery

Epidural Hematoma

Hematomas caused by acute arterial bleeding and commonly form over the parietotemporal convexity.

Cause mass effect and acute neurological symptoms

Epidural hematoma cont…

Radiographic appearance

Midline shift towards opposite side of injury.

Compression of upper mid-brain and brainstem.

Treatment

Emergency surgical decompression

Subdural Hematoma

Venous bleeding, most commonly from ruptured veins between the dura and meninges.

Because of the low pressure tend to have a chronic gradual course with symptoms of headaches, agitation and other neurologic problems, it is hard to diagnose early without radiology exam.

Subdural hematoma cont...

Radiographic appearance

Zone of increased density that follows the surface of the brain and has a crescent shape adjacent to the inner table of the skull.

Treatment

Small subdural hematomas will resorb.

Severe ones require surgical evacuation of the hematoma

Drug therapy

Intraventricular catheter.

Cerebral Contusion

Injury to the brain tissue caused by movement of the brain within the calvaria after blunt trauma to the skull.

Contusions happen when the brain strikes the rough surfaces of the skull such as the orbital roof and petrous ridges

Cerebral contusion con…

Frontal and anterior temporal regions are the most common sites of injury.

Radiographic appearance

Low-density areas of edema and tissue necrosis

Treatment

Hospitalization

Medications

Intracerebral

Hematoma

Traumatic hemorrhage into the brain parenchyma from shearing forces.

Injury to the intima of intracranial vessels can cause the development of traumatic aneurysms.

Intracerebral hematoma cont…

Radiographic appearance

Well-circumscribed, homogeneous, high density region that is usually surrounded by areas of low density edema.

Treatment

Evacuation of acute subdural hematomas.

Surgery if aneurysms

Subarachnoid hemorrhage

Injury to surface veins, cerebral parenchyma, or cortical arteries can produce bleeding into the ventricular system (blood on CSF)

Radiographic appearance

Increased density within the basilar cisterns, cerebral fissures, and sulci.

Treatment

Surgical evacuation and vessel repair if bleeding continues.

Less invasive methods are drug therapy and catheter placement.

Stroke

Neurological deficit due to lack of circulation to the brain.

CVA (cerebral vascular accident) - blood supply to a part of the brain is suddenly interrupted

Ischemic stroke – Complete occlusion

hemorrhage

TIA (Transient Ischemic attack) is a disturbance in brain function that lasts less than 1 hour and results from a temporary blockage of the brain's blood supply

Stroke cont…

Radiographic appearance

The purpose of a radiographic evaluation in the acute stroke patient is not to confirm the diagnosis of the stroke but rather exclude other processes that can simulate the clinical finding.

Initial appearance is a triangular or wedge shaped area of hypodensity.

Eventually produces a mass effect.

Brian tissue atrophies

Stroke cont…

Treatment

All stroke patients are placed on bed rest with reduced external stimuli to lower cerebral oxygen demands.

Medications to lower intracranial pressure

Anticoagulants (Heparin, Warfarin)

Multiple Sclerosis

A chronic progressive disorder that causes demyeliniation of the CNS.

Primarily involves the spinal cord, optic nerve, and central white matter of the brain.

Impairment of nerve conduction caused by degeneration of myelin sheaths.

Multiple Sclerosis cont…

Radiographic appearance

Scattered plaques of demyeliniation .

Treatment

Immunosuppressive agents may help limit the autoimmune attack.

Antiviral drugs may slow down the progress of the disease.

Can only aid in slowing progress. There is no cure.

Alzheimer’s

Disease

Condition that causes cerebral atrophy, causing the patient to be confused, disorientated, and forgetful.

Alzhemiers cont…

Radiographic appearance

Cerebral atrophy, including symmetrical enlarged ventricles with prominence of the cortical sulci.

Treatment

Diet, education, memory aids may help slow the dementia but there is no cure.

................
................

In order to avoid copyright disputes, this page is only a partial summary.

Google Online Preview   Download