Conditions Flashcards
Acalculia
Disturbances in calculation
Acalculia associated with alexia and agraphia for numbers
- Most often associated with left hemisphere disease, but does not rule out right hemisphere involvement
- Alexia for arithmetic signs w/ preserved reading of numbers often associated with left parietal or temporal-occipital regions
- Associated features:
- aphasia
- verbal alexia
- ideational and ideomotor apraxia
- constructional deficits
- somatognosia
Acute Subdural Hematoma
To occur immediately after injury, the impact velocity must be quite high.
Therefore, this is usually associated with other serious injuries, such as traumatic subarachnoid hemorrhage and brain contusion.
Treatment:
- Surgical evacuation
- Small to moderate-sized chronic - depending on severity of symptoms, just follow clinically b/c some will resolve spontaneously
Acalculia of the Spatial Type
- Misalignment of numbers
- Reversal of digits
- Inversion of digits (e.g., 6 for 9)
- Reversal errors (e.g., 12 for 21)
- Actual calculation is largely preserved
- Generally associated with more visual-constructive impairment
- Right hemisphere (post-rolandic) is implicated; rare in pts with lesions confined to left hemisphere
Agnosia
- From Greek word “gnosis” or knowledge, so it means the absence of knowledge
- A disorder of recognition; inability to recognize the meaning of info conveyed w/i a sensory system from external environment to the brain
- Crucial feature: exists only in a singular sensory modality
- Not attributable to:
- Elemetary sensory deficits
- Mental deterioration
- Non-familiarity
- Aphasic misnaming
- Impaired conciousness or attention
Alexia
An acquired deficit in the ability to interpret written language (loss of the ability to read)
Alexia - localization
Disconnection between visual cortex and Wernicke’s area
Anarithmetria
- Deficits in performing the calculation itself (aka, primary acalculia)
- Left sided temporal or occipital lobe lesions. Does not appear to be caused by right hemisphere unless parietal lobe is involved
- Associated with:
- aphasia
- visuoconstructive deficits
- general cognitive deterioration
- verbal alexia
- directional confusion
- visual field deficit
- oculomotor disturbance
- sensory impairment
Anterior Alexia (Frontal Alexia)
More recently discovered so also known as the “Third Alexia” Basic clinical features: - Great difficulty naming individual letters of alphabet but can recognize some written words - Severe agraphia; ability to copy written language poor - Comprehend some spelled words, but poor at spelling aloud - Recognize some semantically meaningful words but fail to comprehend the grammatically significant function words – Agrammatism of written language Accompanying neuro findings: - Right hemiplegia - Nonfluent aphasia - May include unitlateral sensory and/or visual-field neglect Pathology is typically left frontal area Other common names: literal alexia, letter blindness
Apperceptive Agnosia
- Damage fairly early on in recognition assembly line, before perception is properly constructed
- Pts do not perceive objects normally so cannot recognize them
Apraxia
Inability to make sequences of movements
Apraxia - localization
Disconnection between motor and sensory areas
Argyll Robertson Pupils
- Bilateral small pupils that reduce in size when the patient focuses on a near object (accomodate)
- Do not constrict when exposed to bright light
Arteriovenous malformation (AVM)
- Congenital abnormality
- Abnormal direct connections b/t arteries and veins
- Often form a tangle of abnormal blood vessels, best seen on conventional angiography
Assessment of Acalculia
These should be done orally and in written format:
- Appreciation of number values: greater than/less than (e.g., which is greater? 23 or 31?)
- Appreciation of values in written format. Point to the larger number.
- Reading numbers aloud
- Pointing to written numbers read aloud by the examiner
- Writing numbers to dictation
- Copying numbers
- Counting aloud
- Estimating numbers of items in a series of continuous vs discontinuous dots
- Oral arithmetic
- Written arithmetic
- Arithmetic reasoning (WAIS Arithmetic)
- Immediate memory for calculation problems
Qualitatively, look for specific types of errors:
- Substitution of one operation for another (e.g., 2+3=6, substituting multiplication for addition)
- Counting for calculation (e.g., 4+7=8)
- Perseveration of last digit presented (e.g., 4x5=24)
- Giving a reversal of number presented as answer (e.g., 13+6=31)
- Impaired immediate retention of components of problems
Associative Agnosia
- Fault in later stages of recognition
- Perception may be okay, but access to meaning or memory is not
- “A normal percept stripped of it’s meaning”
- Can successfully copy, but not identify
Astrocytoma
- brain cancer arising from glial cells, star-like neurons, aka astrocytes
AVM Symptoms
- Seizures
- Migraine-like headaches
- Hemorrhage is usually intraparenchymal, but can extend to intraventricular or subarachnoid space
Bacterial Meningitis
CSF findings:
- High white blood cell count
- High protein
- Low glucose
Treatment:
- Begin as rapidly as possible
- Do not wait for transport or diagnostic test results
Possible complications of:
- Seizures
- Cranial neuropathies
- Cerebral edema
- Hydropcephalus
- Herniation
- Cerebral infarcts
- Death
Cavernous Malformation
- Abnormally dilated vascular cavities lined by only one layer of vascular endothelium
- Not visible on conventional angiography
- Often presents with seizure
- Risk of bleed 0.1-2.7% per lesion year; increases after initial bleed occurs
Brain Abscess
Presents as an expanding intracranial mass lesion, much like a brain tumor, but often with a more rapid course.
Common presenting features:
- Headache
- Lethargy
- Fever (absent in 40% of cases)
- Nuchal rigidity
- Nausea/vomiting
- Seizures
- Focal signs related to site of lesion
- Elevated white blood cell count (absent in 20% of cases)
Treatment:
- Abscess < 2.5 cm in diameter - antibiotics
- Abscess > 2.5 cm in diameter - steriotactic needle aspiration + antibiotics
Central Alexia (Alexia w/ Agraphia)
Basic clinical features: - severe (not necessarily total) disturbance of both reading and writing - preserved ability to copy written language, but in slavish and non-comprehended manner - loss of ability to name letters, to comprehend spelled words, or to read out loud Often accompanied by other neurobehavioral disorders including: - aphasia - components of Gerstmann Syndrome (finger agnosia, right-left confusion, acalculia, and agraphia) - some degree of hemisensory loss and/or right homonymous visual field defict Locus of pathology includes inferior parietal lobe of language dominant hemisphere, centering on angular gyrus; typically damage to both cortex and white matter Causes most often from occlusion of MCA or distal branches (inferior parietal lobe); may also be caused by neoplastic lesions Other common names: semantic alexia, parieto-temporal alexia, total (literal and verbal) alexia, letter and word blindness, surface alexia
Central Herniation
- Central, downward displacement of the brainstem
- Caused by any lesion associated with elevated intracranial pressure (including hydrocephalus & diffuse cerebral edema)
- Mild herniation:
1. Causes traction on abducens nerve (CN VI) - producing lateral rectus palsey (inability for outward movement of the eye)
2. May be unilateral or bilateral - Large herniation:
1. Herniation through the tnetorial opening, resulting in bilateral uncal herniation - Severe herniation:
1. Can progress downward through the foramen magnum
Chronic Subdural Hematoma
Often seen in the elderly, where atrophy allows the brain to move more freely, making bridging veins more susceptible to shear injury.
May be seen with little to no history of trauma
Oozing slowly, venous blood collects over weeks to months, allowing the brain to accommodate, causing vague symptoms:
- Headache
- Cognitive impairment
- Unsteady gait
Focal dysfunction of the underlying cortex may result in focal neurological deficits
Communicating Hydrocephalus
- Impaired CSF reabsorption in the arachnoid granulations, obstruction of flow in the subarachnoid space, or by excess CSF production
Concussion
- Reversible impairment of neurologic function for minutes to hours following head injury
- Mechanism - unknown (might be transient diffuse neuronal dysfx)
- CT & MRI - normal
- Clinical features:
- LOC
- “seeing stars”
- headache
- dizziness
- nausea
- vomiting
- occasional anterograde and retrograde amnesia for several hours around the injury
- Recovery is usually complete
Epidural Abscess
In the spinal canal and requires prompt diagnosis and tx to prevent:
- Spinal cord compression
- Paraparesis
- Urinary/fecal incontinence
Common presenting features:
- Back pain
- Fever
- Elevated peripheral white blood cell count
- Headache
- Sign of nerve root or spinal cord compression
Treatment:
- Surgical drainage
- Antibiotics (can be used alone in early cases without progressive deterioration)
Epidural Hematoma
Location: B/t dura and skull
Usual cause: rupture of the middle meningeal artery due to fx of temporal bone by head trauma
Clincial features:
- Hematoma, pulls dura away from inner surface of the skull
- Often does not spread past cranial sutures where the dura is tightly apposed to skull
- No sx initially, but within few hours hematoma begins to press on brain tissue
External Ventricular Drain (Ventriculostomy)
- when fluid from the lateral ventricles is drained into a bag outside of the head
General Paresis
Accumulation of lesions associated with meningovascular syphilis, causes:
- Dementia
- Behavioral changes
- Delusions of grandeur
- Psychosis
- Difffuse upper-motor neuron (originate in the motor region of the cerebral cortex or brain stem) type weakness
Gertsmann’s Syndrome
- Agraphia
- Finger agnosia
- Left/right disorientation
- Acalculia - not associated with any specific type of acalculia
Glioblastoma
- The most common type of Stage IV brain cancer
- a type of glioma
- Usually leads to death within 1 year
Herniation
When mass effect is severe enough to push intracranial structures from one compatment into another.
Hydrocephalus
- “water in the head”
- Caused by excessive CSF in the intracranial cavity
Hydrocephalus can result from?
- Excess CSF production
- Obstruction of flow at any point in the ventricles or subarachnoid space
- Decrease in reabsorption via the arachoid granulations
Hydrocephalus Ex Vacuo
- Refers to excessive CSF in a region where the brain tissue was lost as a result of stroke, surgery, atrophy, trauma, or other insult
Inability to read or write numbers - lesion localization
Left parietal; but, does not rule out right hemisphere
Infectious Meningitis
Infection of the CSF in subarachnoid space
Causes:
- Bacteria
- Viruses
- Fungi
- Parasites
Signs/Symptoms:
- Meningeal irritation
- headache
- lethargy
- photophobia
- phonophobia
- fever
- nuchal rigidity
Kernohan’s Phenomenon
When uncal herniation pushes all the way over until it is compressed by the opposite side of the tentorial notch, compressing the contralateral corticospinal tract, leading to ipsilateral hemiplegia.
Lyme Disease
Caused by bacteria from a species of deer tick
Common features:
- Primary infection - raised rash, which gradually shifts location and enlarges over days to weeks
- In some cases, neurological manifestations occur:
- Meningeal signs
- Emotional changes
- Impaired memory/concentration
- Cranial neuropathies (especially facial nerve)
- Peripheral neuropathies
- Spinal cord involvement (rare)
- Non-neurological manifestations:
- Arthritis
- Cardiac conduction abnormalities
Treatment: Intravenous antibiotic
Lymphoma
Arises from B lymphocytes
Commonly involves regions adjacent to ventricles
Treatment: Can be controlled for several years with chemo and radiation
Median survival rate: 4 years
Meningioma
- Arise from the arachnoid villus cells
- Grow slowly
- In females, associated with breast cancer
Meningovascular Syphilis
Causes arteritis (inflammation of the walls of arteries) - typically medium-sized vessels.
Results in diffuse white matter infarcts
Metastatic Tumors
- Arise from neoplasms originating elsewhere in the body that spread to the brain
- 5-8x more common than all primary CNS tumors combined
Neurosyphilis
Transmitted sexually
Stages:
- Painless skin lesions (chancres) appear at the site of infection, about 1 month after exposure
- More diffuse skin lesions appear, characteristically including palms and soles, within 6 months
- Neurologic manifestations
- Aseptic meningitis
- Cranial nerve palsies, especially:
- Optic
- Facial
- Vestibulocochlear
- Cranial nerve palsies, especially:
- 4-15 years after infection, can see:
- Meningovascular syphilis
- Generaly paresis
- Tabes dorsalis
Noncommunicating Hydrocephalus
- Caused by obstruction of flow within the ventricular system
Nontraumatic (Spontaneous) Subarachnoid Hemorrhage
Presentation: Sudden catastrophic headache, feeling like the head is about to explode.
Usual cause: 75-80% rupture of arterial aneurysm in subarachnoid space
Less common: 4-5% bleeding of an arteriovenous malformation
Normal-Pressure Hydrocephalus
- Characterized by chronically dilated ventricles
- Present with clinical triad:
- Gait difficulties
- Urinary incontinence
- Mental decline
- Pressure measurements are usually WNL
- Thought to be a form of communicating hydrocephalus w/ impaired CSF reabsorption at the arachnoid villi
- Some cases improve dramatically after lumbar puncture or ventriculoperitoneal shunting
Nuchal Rigidity
The neck muscles contract involuntarily, resulting in resistance to active and passive neck flexion, accompanied by neck pain.
Obstruction of CSF flow (cause)
- Obstruction of the ventricular system by:
- Tumors
- Intraparenchymal hemorrhage
- Other masses
- Congenital malformations
- Can also occur outside the ventricles in the subarachnoid space by:
- Debri
- Adhesions from prior hemorrhage, infection, or inflammation
Papilledema
- Engorgement & elevation of the optic disc, sometime accompanied by retinal hemorrhages
- Resulting from elevated intracranial pressure, which is transmitted through the subarachnoid space to the optic nerve sheath, obstructing axonal transport and venous return in the optic nerve.
Petechial Hemorrhages
Small spots of blood in the white matter
Pineal Region Tumors
Relatively uncommon -
Include:
- Pinealomas (pineocytoma & pineoblastoma)
- germinoma
- teratoma (rarely)
- glioma (rarely)
Tumors here may:
- obstruct the cerebral aqueduct causing hydrocephalus
- compress the dorsal midbrain, causing Parinaud’s syndrome
Pituitary Adenomas
Can cause endocrine disturbances or compress the optic chiasm (resulting in bitemporalvisual field defect)
Postconcussive Syndrome
- Headaches
- Lethargy
- Mental dullness
- Other symptoms
- can last up to several months after injury
Posterior Alexia (Alexia w/o Agraphia)
Basic clinical features: - Individual can comprehend written material - Writing is almost or totally w/in normal limits BUT can’t comprehend what write - Easily write but have more trouble copying written language With practice, can learn to read most letters out loud; words can then be spelled out loud and recognized auditorially In most cases, ass’d neuro findings include: - right homonymous hemianopia - color naming disturbance Pathology is typically infarction of left posterior artery territory, including splenium of CC (spares angular gyrus) Disconnects visual info from language cortex Other common names: verbal alexia, visual alexia, pure alexia, occipital alexia, associative alexia
Pott’s Disease
Tuberculous involvement of the epidural space and vertebral bones
A kind of tuberculous arthritis of the intervertebral joints
Usually affects lower thoracic and upper lumbar vertebrae
Prevalence and cause of excessive CSF production
- Rare
- Seen only in certain tumors, such as a choroid plexus papilloma
Primary Acalculia
Disturbance in performing calculations specifically
Primary CNS Tumors
- Arise from abnormal proliferation of cells originating IN the nervous system
Risk factors for aneurysmal rupture
- HTN
- Smoking
- ETOH
- Situations causing sudden elevations in BP
Schwannomas are most common where?
CN VIII
Secondary Acalculia
Problems with calculations due to more general disturbances in memory, language, attention, etc The more common of the two acalculia conditions
Signs & Symptoms of Elevated Intracranial Pressure
- Headache - worse in the am b/c of increased brain edema overnight from the effects of gravity in the reclining position
- Altered mental status - irritability, depressed level of alertness/attention
- Nausea & vomiting (projectile)
- Papilledema
- Visual loss - increased blind spot or concentric visual field deficit (affecting mainly peripheral margins of the visual field)
- Diplopia - resulting from downward traction on CN VI, causing unilateral or bilateral abducens nerbe palsies
- Cushing’s triad: HTN (reflex to maintain cerebral perfusion pressure), bradycardia (reflexive response to HTN), irregular respiration (impaired brainstem fx)
Signs & Symptoms of Hydrocephalus
- Headache
- Nausea
- Vomitting
- Cognitive impairment
- Decreased levels of consciousness
- Papilledema
- Decreased vision
- 6th nerve palsies
- if descending white matter pathways from the frontal lobes get compressed:
- Unsteady magnetic gait (barely lifting feet)
- Incontinence
Subarachnoid Hemorrhage
Location: in CSF-filled space b/t arachnoid and pia, which contains major blood vessels of the brain
Radiological appearance: Blood can ben seen to track down into the sulci following the contours of the pia
Usual cause:
- Non-traumatic (spontaneous)
- Traumatic
Subdural Empyema
A collection of pus in the subdural space
Cause:
- Usually direct extension from infection of nasal sinuses or inner ear
Treatment:
- Urgent surgical drainage
- Antibiotics
Subdural Hematoma
Location: in the potential space b/t dura and arachnoid
Usual cause: rupture of bridging veins, which are particularly vulnerable to shear injury as they cross from arachnoid into the dura
Clinical features:
- venous blood dissects relatively easily b/t the dura and arachnoid, spreading out over a large area and forming a crescent-shaped hematoma.
- 2 types
- chronic
- acute
Subfalcine Herniation
- herniation of the cingulate gyrus and other brain structures under the falx cerebri from one side of the cranium to the other
- usually no clinical signs can be attributed directly to this type of herniation
Tabes Dorsalis
Involvement of the spinal cord dorsal roots, especially in the lumbosacral region, resulting in degeneration of the dorsal columns, which results in:
- Sensory loss in lower extremities
- Sensory ataxia, with characteristic high-stepping tabetic gait
- Incontinence
- Argyll Robertson pupils
- Optic atrophy
Tentorial Herniation
- Herniation of the medial temporal lobe, especially the uncus, inferiorly through the tentorial notch
- Clinical triad:
- “Blown” pupil - due to compression of the oculomotor nerve (CN III), ususally ipsilateral to lesion. In uncal herniations, dialated pupil is ipsilateral to lesion 85% of the time
- Hemiplegia - compression of the cerebral peduncles
- Coma - distortion of the midbrain reticular formation leads to decreased levels of consciousness and ultimately coma
Tonsillar Herniation
When the cerebellar tonsils are herniated downward through the foramen magnum
Compresses the medulla, leading to:
- Respitory arrest
- BP instability
- Death
Third Ventriculostomy
- Gaining in popularity for treating hydrocephalus
- Make a perforation in the floor of the 3rd ventricle just in front of the mamillary bodies, allowing CSF to drain into the interpeduncular cistern
Treatment of Pituitary Adenomas
- Dopinergic agonists - will often shrink them
- Transsphenoidal resection
Toxoplasmosis
Initial exposure: cysts in cat feces or undercooked meat - usually asymptomatic
In HIV or other immunosupressant conditions:
- the infection becomes reactivated and spreads to the CNS
- forms brain abscesses (ring-enhancing lesions; MRI dark in the center with a ring of enhancement
Presenting features:
- seizures
- headache
- fever
- meningitis
- focal signs depending upon location of lesion
Tuberculous Meningitis
Cause: Tuberculosis
Common features occurring over the course of weeks:
- Headache
- Lethargy
- Meningeal signs
Problems:
- Often has an inflammatory response in the basal cisterns, which can affect the Circle of Willis vessels, resulting in infarcts.
- Coma
- Hydrocephalus
- Death
Ventriculoperitoneal Shunt
- Shunt tubing that passes from the lateral ventricle out of the skull and then tunneled under the skin to drain into the peritoneal cavity of the abdomen
Viral Encephalitis
When viral infections involve brain parenchyma
Most common cause: Herpese Simplex Virus Type 1
Common features:
- Bizarre psychotic behavior
- Confusion
- Meningeal irritation
- Seizures
Focal signs:
- Anosmia
- Hemiparesis
- Memory loss
- Aphasia
Progression: Causes necrosis of unilateral and bilateral temporal and frontal structures
Results (untreated) within days:
- Coma
- Death
Viral Meningitis
Does not develop or progress as rapidly as bacterial meningitis
Recovery usually occurs spontaneously within 1-2 weeks
Common features:
- Meningeal irritation
Cause: often not identified
Treatment: no specifics, except for Herpes and HIV
What is the normal intracranial pressure in adults?
