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.