Flashcards in Neuro5 Deck (45):
What is the (histo)pathologic hallmark of Creutzfeldt-Jakob Disease (CJD)? What is its cause?
spongiform change in the gray matter
This is caused by prions
What are the clinical characteristics of Creutzfeldt-Jakob Disease?
--rapidly progressive dementia (over months), characterized by memory loss and startle myoclonus. Also mood changes, memory loss, and ataxia
--Abnormal EEG: EEG shows recurrent bursts of high-voltage slow waves
--death usually occurs within 6-12 months of disease onset
How can you differentiate the dementia seen in Creutzfeldt-Jakob Disease from that seen in Alzheimer Disease?
The dementia associated with CJD is rapidly progressive (over months), whereas in Alzheimer Disease, there is a gradual decline in cognitive function, measured in years, not months
*Also, motor dysfunction is generally not observed in AD, whereas it is a common feature of CJD (startle myoclonus)
Where do the axons that ascend in the dorsal columns enter the spinal cord?
In the dorsal root
Pathway of the dorsal column/ medial lemniscus
1st - enter spinal cord via dorsal root
- ascend via fasciculus gracilis or cuneatus
- synapse on 2nd in nucleus g or c in caudal medulla
2nd - decussate as internal arcuate fibers
- ascend to thalamus as medial lemniscus
- synapse on 3rd in ventral posterolateral nucleus
3rd - project to ipsilateral somatosensory cortex
What fibers in the spinal cord would carry information for fine motor control of the left fingers?
The left lateral corticospinal tract (upper motor neurons)
What fibers in the spinal cord would carry information for motor control of the right foot?
The right lateral corticospinal tract (upper motor neurons)
What fibers in the spinal cord would carry information for pain and temperature sensation from the right leg?
The left spinothalamic (anterolaterl) tract
What is the difference between the information carried by the lateral spinothalamic tract versus the anterior spinothalamic tract?
The lateral tract carries pain and temperature information
The anterior tract carries crude touch and pressure information
What is the topography of the lateral corticospinal tract?
(and what information does it carry)
This tract carries voluntary motor information
Cervical (upper body) is medial, sacral (lower body) is lateral. This is the inverse of the topography of the dorsal columns
52 yo man presents at ED because of confusion; appears malnourished, smells of wine. Physical exam shows multiple bruises, nystagmus. What is the most likely diagnosis?
Wernicke-Korsakoff syndrome (wernicke encephalopathy) due to thiamin (vitamin B1) deficiency.
What are the clinical characteristics of Wernicke encephalopathy? (3)
(1) encephalopathy (e.g., confusion)
(2) oculomotor dysfunction (e.g., nystagmus, lateral rectus palsy)
(3) gait ataxia
What are the symptoms of Korsakoff syndrome?
(1) anterograde amnesia (forming new memories)
(2) retrograde amnesia (old memories)
(3) patients often confabulate (make things up) to hide their memory deficits
What are the areas of the brain thought to be involved in Korsakoff syndrome?
The thalamus and mamillary bodies
What is the major difference between Wernicke encephalopathy and Korsakoff syndrome?
Wernicke encephalopathy is reversible; Korsakoff syndrome is irreversible.
Korsakoff syndrome is a late manifestation of untreated Wernicke encephalopathy
How do you treat Wernicke encephalopathy?
Wernicke encephalopathy requires emergent treatment with Thiamine.
**Importantly, Thiamine must be administered before glucose. Administration of glucose prior to thiamine can exhaust the patients thiamine supplies and can precipitate or worsen Wernicke-Korsakoff syndrome because thiamine is a cofactor that is required for the metabolism of glucose.
With what condition is photophobia generally associated?
Inflammation of the meninges, such as in meningitis or in subarachnoid hemorrhages.
(subarachnoid hemorrages can produce a chemical meningitis)
What pathology are resting tremors associated with?
Damage to the substantia nigra, as in Parkinson disease
What are the symptoms of increased intracranial pressure? (6)
(3) bilateral papilledema
(5) nuchal rigidity
(6) mental status changes
What proteins are found in Lewy bodies?
What are the characteristic symptoms of Lewy Body dementia?
(1) visual hallucinations
*The visual hallucinations and early onset dementia differentiate Lewy body disease from Parkinson disease. PD patients do not experience visual hallucinations and experience dementia only late in the disease course
What is the histologic difference between Lewy body dementia and Parkinson disease?
In both diseases, you characteristically find Lewy bodies in the dopaminergic cells of the substantia nigra pars compacts. However, in Lewy body disease, Lewy bodies are also found in cortical regions: the limbic cortex and basal nucleus of Meynert.
How do the histologic features (locations of the Lewy bodies) in Lewy body disease related to the clinical symptoms?
Lewy bodies in:
(1) substantia nigra --> parkinsonism
(2) limbic cortex --> visual hallucinations
(3) basal nucleus of Meynert --> dementia
What are the clinical features of Pick Disease? (4)
(2) changes in personality
(4) parkinsonian aspects
What are the histologic and gross findings in Pick Disease?
--Pick bodies: spherical tau protein aggregates
What is von Hippel-Lindau disease?
autosomal dominant mutation of VHL tumor suppressor gene on chromosome 3.
*--> constitutive expression of HIF transcription factor --> increased production of EPO --> polycythemia
Clinical manifestations of von Hippel-Lindau disease?
(1) retinal angiomas
(2) hemangioblastomas of the CNS (brain stem, especially the cerebellum)
(3) hemangiomas of skin, mucosa, organs
(4) bilateral renal cell carcinomas
(5) polycythemia/ (can manifest in blood test as increased Hb)
Patients with Down syndrome have an extra copy of what gene that would predispose them to down syndrom?
The amyloid precursor protein (APP) gene on chromosome 21
What are the clinical characteristics of Down Syndrome?
(1) intellectual disability
(2) flat nasal bridge
(3) single palmar crease
What conditions are patients with Down Syndrome at increased risk for?
--Acute lymphoblastic leukemia
--Atrioventricular septal defects and mitral valve issues
Mutations in what gene are responsible for most hereditary cases of Alzheimer Disease?
Presenilin-1 and Presenilin-2
Mutations of what gene on chromosome 21 are linked to a subset of cases of amyotrophic lateral sclerosis (ALS)?
Where can HSV-1 establish a latent infection?
In the trigeminal root ganglion
If a cold sore appears on the vermillion of the upper lip, down what nerve must have the HSV-1 virus traveled?
a branch of the maxillary division of the trigeminal nerve, V2
Where does the maxillary division of the trigeminal nerve exit the skull?
the foramen rotundum
Where does the mandibular branch of the trigeminal nerve exit the skull?
the foramen ovale
Where does the ophthalmic branch of the trigeminal nerve exit the skull?
the superior orbital fissure
What exits the skull through the superior orbital fissure?
CN III, IV, V1, VI, ophthalmic vein
Where does the middle meningeal artery exit the skull?
the foramen spinosum
What exits through jugular foramen?
CN IX, X, XI, jugular vein
Where does the hypoglossal nerve exit the skull?
the hypoglossal canal
What passes through the foramen magnum?
--spinal roots of CN XI
Where do CN VII and VIII pass through the skull?
the internal auditory meatus
Where does the optic nerve exit the skull?
the optic canal