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44 Cards in this Set

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Multiple Sclerosis (MS)
Most common demyelinating disorder among Caucasians
1/1000 in US and Europe
Pathogenesis linked to cellular immunity directed against myelin
Oligoclonal bands are detected in CSF protein electrophoresis in most patients (monoclonal associated with cancer)
Presenting symptoms – involvement of optic nerve – optic neuritis and retrobulbar neuritis
But, only 10-50% of patients with optic neuritis develop MS
A 32-year-old woman presented with a 3 month history of waxing and waning unilateral visual impairment and facial numbness
An MRI of the brain revealed several sharply circumscribed lesions in the white matter, adjacent to the lateral ventricles and involving the visual pathways consistent with multiple sclerosis
CSF protein electrophoresis revealed “oligoclonal bands”
MS Histo
Active:
Ongoing myelin breakdown
Lipid-laden, PAS-positive macrophages
Perivascular mononuclear inflammatory infiltrate (“perivascular cuffs”)
.//

Inactive:

Sharp demarcation between myelinated and demyelinated
Prominent gliosis
Axonal depletion
Reduced number of oligodendrocyte nuclei.//
MS Gross
Gross: plaques colored like the gray-matter especially around lateral ventricles, optic nerve, and brainstem.
Lyme Dz
The great mimic of Multiple Sclerosis
Remember that MS is rarely seen at the Equator
It doesn’t take much to check for Lyme Disease, check camping history, etc.
Uveal Melanoma
Malignant melanoma arising from a preexisting nevus in the posterior portion of the choroid. The retina is elevated as the tumor bulges into the vitreous cavity. Malignant melanoma is the most common malignant intraocular tumors. The tumor arises from melanocytes or nevi in the uveal tract.
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Clinical Features:
Most frequently occurring intraocular tumor in adults
Risk factors
UV light
History of cutaneous melanoma or multiple nevi
Family history of ocular melanoma
Light color of the iris
Protective features: Black skin, brown iris, glasses
A 75 year-old man presents to your office because he can no longer see out of his left eye.
He tells you that his vision has been getting progressively worse over the last six months, and he attributed it to old age, but yesterday, he went totally blind in his left eye.
Upon examination, you find the patient is jaundiced and hypertensive.
Ophthalmoscope examination reveals a mushroom shaped growth and extensive hemorrhage in the left eye.
What is the uveal tract?
The pigmented vascular coat of the eye consisting of the
iris, ciliary body and choroid.
Uveal Melanoma: Presenation
Presentation:
Patient with decreased vision or blindness and with an enlarged liver
If the melanoma occurs in the iris, it may change the color of the iris
Late manifestations
Glaucoma,
Cataracts
retinal detachment
No pain unless there is associated glaucoma or inflammation
What location of uveal melanoma is associated with a better px?
The iris, at this site they are usually detected earlier and may
even be resected (not enucleated).
Uveal Melanoma: What marker is used?
Look for tumor marker: HMB-45
Uveal Melanoma: treatment and most common cause of death?
Resection for a few (iris), radiation, enucleation and chemotherapy (extraocular).
--------------

Liver metastases. Conjunctival melanoma is localized
Uveal Melanoma: Histo
Histological types:
--Spindle
-A (no visible nucleoli)
-B (prominent nucleoli readily visible)
--Epithelioid (polygonal cells with identifiable borders and nucleoli)

Most tumors are a mixture of the three different types with some necrosis.
Uveal Melanoma: What features indicate an adverse prognosis?
Epithelioid cells
Large size
Involvement of the ciliary body
Extrascleral extension
Older patient
Increased mitotic activity
What other infections and inflammatory conditions affect the uvea?
Bacterial, Viral, Fungal
Sarcoidosis: uveal involvement is common involving about one-third of patients
Sympathetic ophthalmia: autoimmune bilateral granulomatous inflammation secondary to a traumatic injury in one eye.
This condition, although rare, arises within a few weeks of the injury. Once the autoimmune response begins, bilateral blindness is usually the final result.
The ophthalmologist must decide in a few weeks whether to remove the injured eye to prevent the response.
Uveal Melanoma: What is the pattern of spread and how it differs from
melanoma of the skin?
Direct extension through the scleral canal
Local metastases through intravascular spread
General metastases: hepatic metastases predominate, 95% of uveal melanomas with metastases have liver involvement
While melanoma of the skin spreads through the lymphatic channels, uveal melanoma spreads hematogenously because there are no lymphatic channels in the eye
How does conjunctival melanoma differ from uveal
melanoma?
Accounts for 5% of ocular melanomas
Behaves like typical melanoma of the skin
Has propensity for local recurrence
Retinoblastoma
The most frequently occurring intraocular tumor in children.
On physical examination, leukocoria is present.
Median age of dx is 2 years in boys and 1 year in girls, if unilateral. Less than 1 year if bilateral.
70-75% unilateral, of these 10-15% have germline mutation

95% cured!!!
Retinoblastoma: epidemiology
Results from defect in RB gene, a tumor suppressor gene at 13q14.
Hereditary and non-hereditary forms. Bilateral tumors in hereditary retinoblastoma.
Believed to arise from neuroepithelial cell in retina
Increased risk of osteosarcoma
Retinoblastoma: Histo
Small round blue cells with hyperchromatic nuclei and minimal cytoplasm.

Flexner Wintersteiner rosettes and numerous mitotic figures.
Acoustic Schwannoma
Derived from Schwann Cells which produce the myelin sheath of nerves
S-100 Positive
Associated neurons are largely excluded from the tumors although they may become entrapped within the profiferating Schwannian elements//

Intracranially, involves the eighth nerve, arising from the point where the nerve starts to acquire Schwann cells (internal auditory meatus)
Produces tinnitus (ringing) and deafness
If growth into the cerebellopontine angle, compression of other cranial nerves may occur//
A 35-year-old male physician presented with a six month history of gradually increasing difficulty hearing and tinnitus in one ear
What would you have to rule out if MRI studies disclosed
bilateral lesions at the cerebello-pontine angle?
Type 2 neurofibromatosis
Acoustic Schwannoma: Gross
Intracranially, involve the vestibular branch of the eighth cranial (acoustic) nerve
May also affect peripheral nerves//

Antoni A = High cellularity
May contain Verocay bodies//

Antoni B = low cellularity
Nerve pushed to side
Type 2 neurofibromatosis
Patients with neurofibromatosis (esp NF2) have
acoustic schwannomas (that may be bilateral)
multiple meningiomas
Incidence of 1 in 40-50,000
NF2 gene located on chromosome 22q12 – is a tumor supressor gene
Type 1 neurofibromatosis
von Recklinghausens disease
Incidence of 1 in 3000
Café au lait spots
Lisch nodules in iris
Autosomal dominant mutation at 17q11.2
Polio Encephalomyelitis
Poliovirus
Enterovirus of picorna virus family
In 90-95% of cases (non-immunized) produces inapparent infection or mild gastroenteritis
In 1 %, invades the CNS, replicates in motor neurons of spinal cord or brain stem
1% of these develop permanent paralysis
2-5% of children and 15-30% of adults die of respiratory failure
Bulbar polio (cranial nerve involvement) is grave sign
An 8-year-old male child was admitted with fever and rigidity of the neck
Shortly thereafter, the patient developed cramping muscle pain, spasms, coarse twitching and weakness in upper and lower extremities, progressing to quadriplegia and paralysis of the respiratory musculature
Despite antibiotics and supportive therapy the patient died of pneumonia
Polio: Gross
Congestion and edema of cord
Hemorrhage within gray matter of cord

This is diagnostic of polio
Polio: Histo
Destruction of anterior horn motor neurons of the spinal cord
If fulminant disease, cranial nerve nuclei may be involved
Hemorrhage, vascular congestion, lymphocytic infiltration of gray matter
Polio: Epidemiology
Higher incidence in disadvantaged urban and rural areas (lack of immunization
Favors infection of anterior motor neurons of spinal cord, leading to subsequent flaccid paralysis of one or more limbs
Muscle wasting and hyporeflexia follow in permanently damaged areas
Cranial nerve involvement is much less common
Acute Bacterial Meningitis
Causative Bacteria
Neonates
E.coli, Group B streptococci
Infants and children
S. pneumoniae
Adolescents and young adults
N. meningitidis
Very young and old
- S. pneumoniae and Listeria monocytogenes
A 19-year-old male enlistee in boot-camp presents with fever, headache, stiff neck and mild stupor
Phys Exam Findings
Kernig sign – with thigh flexed, the leg cannot be extended
Brudzinski signs – with flexion of neck there is reflex flexion of ankle, knee and hip
these reflexes immobilize and reduce stretching of the inflamed meninges
What agent would you suspect if he developed petechial or
purpuric skin lesions?
N. meningitidis
Acute Bacterial Meningitis: Gross
Brain and spinal cord swollen and congested
Exudate within subarachnoid space with clouding and congestion of leptomeninges – railroad tracking
Acute Bacterial Meningitis: Histo
Neutrophilic infiltrate in subarachnoid space
Variable amounts of fibrin
No extension into brain or cord parenchyma
Congestion of vessels
Waterhouse-Friederickson Syndrome
N. meningitidis, Pseudomonas, H. influenza, pneumococci, and sometimes due to staphylococci
Rapidly progressive hypotension leading to shock
DIC with widespread purpura
Rapidly developing adrenocortical insufficiency (adrenals converted to sacs of blood)
Acute Bacterial Meningitis: CSF Findings
Cloudy or purulent fluid
Increased pressure
Numerous neutrophils
Increased protein
Markedly decreased glucose content
Rabies
Caused by RNA virus
Produces severe encephalitis that is almost always fatal
Virus ascends through peripheral nerves to CNS
Gives a “lag-time” of 1-3 months from time of bite of infected animal to clinical disease
Allows opportunity to prevent disease through active immunization with rabies vaccine

Virus secreted into saliva of animal then to human through bite
Incubation period (time to ascend nerve) depends on location of bite,
e.g. face – short period
leg – longer period
In advanced stages, slightest stimulus evokes painful, violent motor responses of convulsions
A 25-year-old U.S. Marine corporal was bitten by a raccoon while hiking at Great Falls Park
Two months later he was admitted to Walter Reed Medical Center with evidence of encephalitis, including agitation, confusion, seizures, fever, cranial nerve palsies, difficulty swallowing with excessive salivation resulting in “foaming at the mouth,” and finally coma
He died 4 days after the onset of symptoms
Rabies Histo:
Edema and vascular congestion of brain and brain stem
Widespread neuronal degeneration
Chronic inflammation most intense in mid-brain, basal ganglia and floor of 4th ventricle
Negri bodies (pathognomonic)
In neurons esp. of Ammons Horn and Purkinje cells
What other animals should you fear the most due to rabies risk?
Dogs, skunks, foxes and bats predominantly. Roughly about
3% of cases documented in animals were in dogs.
Who should receive rabies vaccines?
Occupations at risk, travel to foreign countries.
What are the most common CNS opportunistic infections and neoplasms in HIV patients?
Toxoplasma encephalitis
Cryptococcal meningitis
Primary CNS Lymphoma
Progressive Multifocal Leukoencephalopathy
AIDS Dementia Complex
CMV encephalitis
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Neurologic illness develops in 40-60% of HIV+ people.
If an HIV patient is seropositive for PCP, should they be placed on prophylactic therapy? How is this similar/different than prophylactic Tx for toxoplasma?
Should receive prophylaxis to PCP if CD4 < 200 or has a history of oral candidiasis. TMP-SMZ is recommended agent.
-------------
Should receive prophylaxis to Toxoplasma if CD4 < 100. Double-strength TMP-SMZ is sufficient.
What is the most common manifestation of cerebral cysticercosis?*
Seizures which have two primary settings:
Patients who present initially with seizures with identifiable cystic lesions. Cysts are antigenic and can invoke an immune response.
Patients treated previously without recognizable cystic structures by MRI or CT, but with residual calcified lesions commonly have seizures. Symptoms correspond to edematous foci.
34 year old woman diagnosed with tapeworm infection while in Brazil
2 years later sudden onset of seizures
Started on dilantin but continued to have seizures
CT reveals multiple round, noncystic enhancing lesions in left frontal, parietal, occipital regions
Stool O & P x3 negative
“Swiss-cheese” homonymous partial field deficit in right upper quadrant
Patient has nodules on thigh. X-ray reveals “cigar-shaped” calcifications in thigh and calf muscles
DDX for Cysticercosis
Hydatid Disease
Cysticercosis (larval Tania solium)
Other cyclophyllidean larva (coernurus, cysticercoid, strobilocercus, tetrathyridium)
Sparganosis
Migrating fluke
Non-filarial nematode (Angiostrongyliasis)
Neoplasm (low-grade astrocytoma and cystic cerebral metastases
Foreign body
What are the two types of macular degeneration?*
Atrophic (dry) form
Bruch membrane thickens focally and generally, called “drusen”
Choriocapillaries become obliterated
Retinal pigment epithelium (RPE) becomes atrophic and depigmented
Underlying photoreceptors atrophy and degenerate, leading to permanent loss of vision

-----------

Exudative (wet, disciform) form
Worsening Bruch membranes disrupt vascular membranes beneath retina
These vascular beds leak, produce exudate, heomorrhage under retina
This triggers retinal pigment overgrowth (fibrous metaplasia)
Fibrous overgrowth transforms into scar, leads to degernation of neuroretina and permanent vision loss.
55 year-old male pilot comes seeking an opthalmologic referral
Eyesight progressively worsened over last few months
Has never needed glasses, eyesight previously fine
Opthalmologic examination reveals clear retina, but discoloration surrounding the fovea bilaterally
How are patients with macular degeneration treated?
Atrophic (dry) form
There is currently no medical treatment available
------------
Exudative (wet, disciform) form
If discovered early, prior to scar formation, laser treatment to affected vasular channels may prevent any further loss of vision