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44 Cards in this Set
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Multiple Sclerosis (MS)
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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” |
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MS Histo
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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.// |
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MS Gross
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Gross: plaques colored like the gray-matter especially around lateral ventricles, optic nerve, and brainstem.
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Lyme Dz
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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. |
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Uveal Melanoma
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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.
---------- 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. |
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What is the uveal tract?
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The pigmented vascular coat of the eye consisting of the
iris, ciliary body and choroid. |
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Uveal Melanoma: Presenation
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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 |
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What location of uveal melanoma is associated with a better px?
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The iris, at this site they are usually detected earlier and may
even be resected (not enucleated). |
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Uveal Melanoma: What marker is used?
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Look for tumor marker: HMB-45
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Uveal Melanoma: treatment and most common cause of death?
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Resection for a few (iris), radiation, enucleation and chemotherapy (extraocular).
-------------- Liver metastases. Conjunctival melanoma is localized |
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Uveal Melanoma: Histo
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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. |
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Uveal Melanoma: What features indicate an adverse prognosis?
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Epithelioid cells
Large size Involvement of the ciliary body Extrascleral extension Older patient Increased mitotic activity |
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What other infections and inflammatory conditions affect the uvea?
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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. |
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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 |
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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 |
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Retinoblastoma
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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!!! |
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Retinoblastoma: epidemiology
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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 |
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Retinoblastoma: Histo
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Small round blue cells with hyperchromatic nuclei and minimal cytoplasm.
Flexner Wintersteiner rosettes and numerous mitotic figures. |
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Acoustic Schwannoma
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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
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What would you have to rule out if MRI studies disclosed
bilateral lesions at the cerebello-pontine angle? |
Type 2 neurofibromatosis
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Acoustic Schwannoma: Gross
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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 |
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Type 2 neurofibromatosis
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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 |
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Type 1 neurofibromatosis
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von Recklinghausens disease
Incidence of 1 in 3000 Café au lait spots Lisch nodules in iris Autosomal dominant mutation at 17q11.2 |
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Polio Encephalomyelitis
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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 |
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Polio: Gross
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Congestion and edema of cord
Hemorrhage within gray matter of cord This is diagnostic of polio |
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Polio: Histo
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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 |
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Polio: Epidemiology
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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 |
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Acute Bacterial Meningitis
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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
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Phys Exam Findings
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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 |
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What agent would you suspect if he developed petechial or
purpuric skin lesions? |
N. meningitidis
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Acute Bacterial Meningitis: Gross
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Brain and spinal cord swollen and congested
Exudate within subarachnoid space with clouding and congestion of leptomeninges – railroad tracking |
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Acute Bacterial Meningitis: Histo
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Neutrophilic infiltrate in subarachnoid space
Variable amounts of fibrin No extension into brain or cord parenchyma Congestion of vessels |
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Waterhouse-Friederickson Syndrome
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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) |
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Acute Bacterial Meningitis: CSF Findings
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Cloudy or purulent fluid
Increased pressure Numerous neutrophils Increased protein Markedly decreased glucose content |
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Rabies
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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 |
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Rabies Histo:
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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 |
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What other animals should you fear the most due to rabies risk?
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Dogs, skunks, foxes and bats predominantly. Roughly about
3% of cases documented in animals were in dogs. |
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Who should receive rabies vaccines?
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Occupations at risk, travel to foreign countries.
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What are the most common CNS opportunistic infections and neoplasms in HIV patients?
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Toxoplasma encephalitis
Cryptococcal meningitis Primary CNS Lymphoma Progressive Multifocal Leukoencephalopathy AIDS Dementia Complex CMV encephalitis ---------- Neurologic illness develops in 40-60% of HIV+ people. |
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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?
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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. |
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What is the most common manifestation of cerebral cysticercosis?*
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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 |
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DDX for Cysticercosis
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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 |
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What are the two types of macular degeneration?*
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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 |
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How are patients with macular degeneration treated?
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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 |
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