Neurology Notes

Case presentation

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Symptoms of Neurologic disorders
Delirium and dementia

Aphasia, apraxia, and agnosia
 

Classification of aphasias

	fluency	comprehension	naming	repetition
Broca's	Abnormal		Abnormal	Abnormal
Wernicke's		Abnormal	Abnormal	Abnormal
Transcortical motor	Abnormal		Abnormal
Transcortical sensory		Abnormal	Abnormal
Global	Abnormal	Abnormal	Abnormal	Abnormal
Conduction				Abnormal
Anomic			Abnormal

• Aphasia Branches of the left sylvian arrtery supply the opercular and insular regions surrounding the sylvian fissure.
• Motor aphasias a focal infact to the gyrus of the unsula or the upper banks of teh opercular cortex from the anterior inferior frontal region to the anterior parietal .

speech dyspraxia: dysprosody, dysphonia, dysarthria
the larger the lesion, the more dysphasic: agrammatism is an important sign of the extent of the lesion.
• Broca aphasia : formally defined is the residual motor aphasia after a larger total aphasia. Classically it does not define a discrete lesion in broca's araa. (pars opercularis of teh inferior frontal gyrus).
• Sensory aphasia posterior portions of the brain are more compact and large infarctions or mass lesions from hemorrhage abscess, encephalitis or brain tmors cause similar clinical disordrers. Conralateral hemianopsia usually implies a deep lesion, If the hemianopsia persist > 1 week, the aphasia is likely to persist.
• Amnestic aphasiaAnomia or dysnomia is the term applied to error in tests of naming. dysnomias accompanying literal or verbal paraphasias have little localizing value, However, Amnestic dysnomia: patient acts as though the name has been forgotten, and may give functional descriptions instead. Usually disease of the deop temporal lobe and gray and white matter. Alzheimers is the most common cause.
• Thalamic aphasia

acute deep lesion on the side of the dominant hemisphere affecting the posterior thalamic nuclei that have reciprocal connections with the language area. Usually associated with fluctuating levels of consciousness

Infections of the nervous system
Bacterial infections

Focal infections
Viral infections
Acquired immunodeficiency syndrome
Fungal and yeast infections
Neurosarcoidosis

• prevalence 3-50/100000
• Onset most often in 4th or 5th decade
• Lesions can affect any organ, especially lung, lymph nodes, skin, bone, eyes, and salivary glands.
• Work up reveals systemic disease in 97% of cases.
• Usually involve meninges at the base of the brain.
• Clinical presentation: CN7 most often affected. associated uveitis and parotitis. Facial weakness can be bilateral, either simultaneous or sequential, and can recur after recovery. CN5 and CN8 can be involved. Diabetes insipidus, decreased libido, galactorrhea, amenorrhea, abnormal sleep patterns, alterel appetite, temperature dysregulation and abnormal behavior.

neurosyphilis

leptospirosis

Lyme disease
Parasitic infections
Bacterial toxins
Reye syndrome
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Vascular diseases
pathogenesis, classification and epidemiology of cerebrovascular disease

Vascular anatomy

• Right common carotid:CCA originates from the bifurcation of the innominate,
• Left originates directly from the aortic arch.
• the ICA starts usu at C4.
• Four segments: cervical, petrous, cavernous, supraclinoid
• branches of the ICA: ophthalmic, superior hypophyseal, MCA, ACA, posterior communicating, and anterior choriodal.
• examination of the patient with cerebrovascular disease
• transient ischemic attacks
• cerebral infarction
• Atherothrombotic disease of the vertebrobasilar-posterior cerebral artery system
• Posterior Cerebral Artery
• Pathophysiology
• 70% PCA arises from basilar bifurcation
• 22% have one arising from MCA
• 8% have both from MCA
• Clinical manifestations: Proximal Precommunal syndromes
• Claude's syndrome: third nerve palsy and contralateral ataxia
• Weber's syndrome contralateral hemiplegia with third nerve palsy
• Occlusion of the penetrating branches of the thalamic and thalamogeniculate arteries produces less extensive thalamic and thelamocapsular lacunar syndromes.
• Thalamic syndrome of Dejerine and Roussy: Contralateral hemisensory loss of both superficial sensation (pain and temperature) and deep sensation (touch and proprioception). Occasionally anticonvulsants may be beneficial.
• Postcommunal syndromes (peripheral or cortical territory)
• contralateral homonymous hemianopsia
• central vision may be spared if the MCA supplies cortical blood to those areas.
• Alexia without agraphia: results from infarction of the dominant hemisphere and extends to involve the splenium of the corpus callosum.
• Also, visual agnosia for faces (prosopagnosia?), peduncular hallucinations (visual hallucinations of brightly colored scenes and objects).
• Bilateral infarction of the visual cortex: cortical blindness.: patient is usually unaware. Normal pupillary reaction
• Balint's syndrome: unilateral or bilateral visual association area lesions.  Optic ataxia (inability to visually guide limb movements), ocular ataxia (inability to direct eyes to a precise point in the visual field, inability to enumerate objects in a picture or extract meaning from a picture, and inability to avoid objects seen in one's path.  This usually seen in low flow bilateral infarctions "watershed" territories as occurs after arrest.
• embolic occlusion to top of basilar can produce a clinical picutre that includes any or all of the central or peripheral territory symtpms.  Its hallmark is suddenness of onset and bilaterality of symptoms, including ptosis, somnolence.

Cerebral and cerebellar hemorrhage

Other cerebrovascular syndromes

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stroke in children

treatment and prevention of stroke

subarachnoid hemorrhage

cerebral veins and sinuses

vascular disease of the spinal cord

Disorders of  the cerebrospinal and brain fluids

• Obstructive hydrocephalus
• Congenital malformation or developmental lesions
• Postinflammatory or post hemorrhagic
• Mass lesions
• Communicating hydrocephalus
• Normal Pressure Hydrocephalus
• Is a potentially treatable cause
• absence of papilledema with normal CSF pressure at LP
• often follows head trauma, subarachnoid hemorrhage, or meningiits or is associated with occult mass lesion.
• Pathophysiology: unknown. obliteration or insufficiency of the transcortical subarachnoid space. +/- impaired absorption defect at the arachnoid villi, leading to reduced conductance to CSF outflow.

Clinical signs: insidious onset, gradual development for weeks or months of dementia, ataxia of gait, and urinary incontinence.  HA and signs of increase intracranial pressure do NOT occur.  May begin weeks after head trauma or subarachnoid hemorrhage.  In advanced disease there may be frontal release signs, hyperactive tendon reflexes and Babinski signs.
• Laboratory data: improvement with removal of 30-50 cc CSF.  CT or MRI evidence or transependymal diffusion of fluid;" isotope cisternography" a measure of the direction of CSF flow, with reflux of CSF from the subarachnoid space to the lateral ventricles, reversing the normal flow and delayed clearance or intraventricular transependymal penetration of the isotope;  CSF compartment infusion or perfusion tests: intracranial pressure monitoring to assess high pressure waves; dynamic MRI, cerebral angiography for intracranial mass lesions.
• Prognosis and treatment: choroid plexectomy for papilloma.  ventriculocisternal shunting, craniospinal to extracranial reservoidr (ventriculopleural shunt).  No pharmacologic treatment is satisfactory.

Tumors

Trauma

• Craniocerebral trauma:
• may be divided according to the nature of injury to the skull into three groups:
• Closed head injuries: no injury to the skull or only a linear fracture.
• Concussion: no gross stuctural damage
• Contusion: destruction of brain tissue related to edema, laceration and hemorrhage
• Depressed fractures: pericranium is intact but a fragment of fractured bone is depressed inward to compress or injure the underlying brain.
• Compound fracture: fracture of the fragments leads to comminuted fracture and communication between scalp and cerebral substance
• Pathology Concussion and diffuse brain injury: depends on time
• if coma < 6 h presumably, no histology change, no permanent sequelae
• if coma 6-24h, diffuse axonal injury has been observed.

Diffuse Axonal Injury (DAI):
• three forms:
• focal lesion in the corpus callosum,
• focal lesion in the dorsolateral quadrants of the rostral brain stem,
• Cerebral edema: different from brain edema in that brain edema has primarily increased extravascular brain water. In traumatic cerebral edema, intravascular volume of blood is also increased due to vasodilatation.
• Contusion and laceration
• contusion: pia and arachnoid are intact. are most severe in frontal and temporal lobes, tend to occur as a result of occipital impacts than vice versa.
• laceration: these are disrupted.
• Emergency care and evaluation
• Glascow Coma scale
• exceptions: not valid for children, and the postictal, shock, hypoxic, or intoxicated patient.
• radiography and imageing
• course and prognosis
• treatment
• Complications of Head Injuries
• subarachnoid hemorrahge
• extradural hemorrhage
• subdural hematoma
• subdural hemorrhage in infants
• subdural hygroma
• Three major causes
• cranial trauma with tearing of the arachnoid and escape of csf into the subudral space: here CSF is usually mixed with blood owing to coincident rupture of the meningeal vessels
• post influenzal viral infection
• rupture of the arachnoid at the basal cistern following communicating hydrocephalus.
• traumatic intracerebral hemorrhage
• Cerebral thrombosis
• carotid-cavernous fistulae
• Infections
• extradural
• subdural abscess
• meningitis
• brain abscess
• CNS fistulae: rhinorrhea and otorrhea
• pneumocele
• leptomeningeal cysts: formation of a cyst between the pia mater and arachnoidal membrane. may develp when there is a linear fracture of the skull with separation of the edges of the fracture. Pulsation of the brain forces csf into the cyst and produces erosion of the skull. Most commonly seen following fracture of the the skull in infants and young children. Signs and symptoms include convulsive Sz, MR, increased intracranial pressure. Dx radiography , Rx excision of the cyst and repair of the dural defect
• cranial nerve palsies
• focal cerebral lesions

• Etiology
• Mechanism of Injury
• Pathology
• Signs and symptoms
• Patterns include
• cauda equina lesions : flaccid afeflexic paralysis and sensory loss in the area supplied by the affectied roots, with paralysis of bladder and rectum.
• conus medullaris lesions : If only the conus is affected, there is urinary fecal incontinence, failure of erection and ejaculation in men, paralysis of the pelvic floor muscles; and sensory impairment; which is frequently dissociated in the saddle region. In a pure conus lesion: tendon relfexes are frequently preserved, but occasionally the ankle jerks are lost.
• mixed cauda-conus lesions
• spinal cord injuries
• Cord cuncussion: used to describe transient neurologic symptoms with recovery in minutes or hours. Symptoms develop below the level of the injury
• Spinal shock: immediate complete paralysis and anesthesia below the lesion, with hypotonia and areflexia. plantar can be anything. areflexia gradually transforms to pyramidal signs 3-4 weeks including hyperreflexia (but UTIs, bedsores, anemia or malnutrition may delay this transition)
• Complete cord transections: permanent motor, sensory, and autonomic paralysis below the level of the lesion.
• Incomplete cord transection
• Brown-Sequard syndrome: Hemisection of the spinal cord, usually with the upper level one or two segments below that of the lesion: Ipsilateral paresis, ipsilateral corticospinal signs, contralateral loss of pain and temperature, ipsilateral impairment of vibration and JPS. Tactile sensation usually preserved.
• central cervical cord syndrome: weakness (arms>legs), urinary retention, patchy sensory loss below the level of the lesion. Arms and hands may be paralyzed or moderately weak, with contibutions from the damaged anterior horn cells. In the legs, severe paresis or minimal weakness may exist, overactive tendon reflexes and babinski. Initial presentation may be that of complete cord transection but later testing may show sacral sparing. If so, potential for recovery without operative intervetion is better and depends on the degree of central hemorrhage.
• anterior cord syndrome: immediate complete paralysis is associated with mild to moderate impairment of pinprick response and light touch below the injury. spared are the dorsal columns, therefore, JPS and vibration are intact.
• posterior cord syndrome: Pain and paresthesisas are usually symmetric and have a burning quality. Mild paresis of arms and hands, but the long tracts are only slightly affected.

• Diagnosis
• Course and prognosis
• Treatment
• Complications
• Rehabilitation

• Pathogenesis:
• Lumbar Intervertebral Disc Rupture
• Thoracic Disc Rupture
• Cervical Disc Disease
• Signs and symptoms
• Diagnostic features
• Treatment

Birth injuries and development abnormalities

Genetic diseases of the central nervous system

• CHROMOSOMAL DISEASES
• DISORDERS OF AMINO ACID METABOLISM
• DISORDERS OF PURINE METABOLISM
• LYSOSOMAL DISEASES AND OTHER STORAGE DISEASES
• Lipidoses
• GM2-Gangliosidoses
• Infantile encephalopathy with Cherry-Red spots
• Tay-Sachs
• Sandhoff disease
• AB variant
• Late Infantile, Juvenile, and adult GM2-gangliosidoses
• GM1-Gangliosidosis: This group of disorders is characterized by deficiency of GM1-ganglioside beta-galactosidase and storage of compounds that contain a terminal beta-linked galactose moiety.
• Infantile GM1-gangliosidosis
• Late Infantile GM1-gangliosidosis
• Fabry Disease
• Gaucher Disease
• Niemann-Pick Disease
• Farber disease
• Wolman disease
• Refsum disease
• Cerebrotendinous xanthomatosis
• Neuronal lipofucsinosis

• DISORDERS OF CARBOHYDRATE METABOLISM
• HYPERAMMONEMIA
• PEROXISOMAL DISEASES: ZELLWEGER SYNDROME,
• ADRENOLEUKODISTROPHY, AND REFSUM DISEASE
• ORGANIC ACIDURIAS
• DISORDERS OF METAL METABOLISM
• ACUTE INTERMITTENT PORPHYRIA
• ABETALIPOPROTEINEMIA
• XERODERMA PIGMENTOSUM
• CEREBRAL DEGENERATIONS OF CHILDHOOD
• DIFFUSE SCLEROSIS
• DIFFERENTIAL DIAGNOSIS

Mitochondrial encephalomyopathies

• MITOCHONDRIAL ENCEPHALOMYOPATHIES: DISEASES OF MITOCHONDRIAL DNA
• LEBER HEREDITARY OPTIC ATROPHY
• MITOCHONDRIAL DISEASE WITH MUTATIONS OF NUCLEAR DNA

Neurocutaneous disorders

• NEUROFIRBROMATOSIS
• ENCEPHALOTRIGEMINAL AGIOMATOSIS
• INCONTINENTIA PIGMENTI
• TUBEROUS SCLEROSIS

Peripheral neuropathies

• Peripheral Neuropathies: diffuse lesions of perpheral nervs, usually manifest by weakness, sensory loss, and autonomic dysfunction
• Mononeuropathy: disorder of a single nerve, usus entrapment, or trauma
• Mononeuropathy multiplex: signifies focal involvement of two or more nerves, usually as a result of a generalized disorder such as DM or vasculitis.
• Neuritis typically reserved for inflammatory disorders of nerves resulting from infection or autoimmunity.
• Symptoms and signs
• age: Charcot-Marie-Tooth begins at childhood whereas paraproteinemia is in adulthood
• onset and progression: GBS, tick paralysis, and prhyria begin acutely and may remit. B12 deficiency or carcinomatous neuropathy begin insidiously and progress slowly.

Subtype affected:

ACQUIRED NEUROPATHIES

• Guillain-Barre syndrome and variants
• Chronic Inflammatory demyelinating polyneuropathy
• Idiopathic sensory neuronopathy or ganglioneuritis
• Idiopathic Autonomic neuropathy
• Vasculitic and cryoglobuinemic neuropathy
• Neuropathies associated with myeloma and nonmalignant IgG or IgA monoclonal gammopathies
• Motor, Sensory and Sensorimotor Neuropathies associated with IgM monoclonal or polyclonal autoantibodies to peripheral nerve
• Amyloid Neuropathy
• Neuropathy associated with Carcinoma (paraneoplastic neuropathy)
• Hypothyroid neuropathy
• Acromegalic neuropathy
• Hyperthyroid neuropathy
• Uremic neuropathy
• Neuropathy associated with hepatic disease
• Neuropathies associated with infection
• Leprosy
• Diphtheria
• HIV
• Herpes Zoster
• Sarcoid
• Polyneuropathy associated with dietary states
• Critical illness polyneuropathy
• Neuropathies produced by metals
• Arsenic
• Lead
• Mercury
• Thallium
• Neuropathies caused by therapeutic agents
• diabetic neuropathy
• acute painful polyneuropathy
• mononeuropathies
• generalized polyneuropathies
• brachial neuropathy
• radiation neuropathy
• Lyme neuropathy

Dementias

• Alzheimer Disease
• Most common form
• Epidemiology: prevalence 10.3% in age 65, rising to 45% at age 80. Incidence 2.6% over age 65
• Etiology: genetic basis: chromosome 21, 14 for young onset, familial disease. for Late onset chromosome 19 Apo-E isoform. Highly associated, also, history of head injury, low levels of education.
• Cerebrovascular dementia
• Parkinson's
• Huntington
• HIV associated dementia
• Characterized by apathy, memory loss, cognitive slowing,
• Clinical features useful in diagnosis of HIV-related dementia
• HIV-1 seropositivity (western)
• History of progressive cognitive and behavioral deline, with apathy, memory loss, slowed mental processing
• Neuro exam: diffuse CNS signs, including slowed rapid eye and limb movements, hyperreflexia,hypertonia, and release signs.
• Neuropsychological assessment: progressive deterioration on serial testing in at least two areas, including frontal lobe functions,motor speed, and nonverbal memory
• CSF: nonspecific IgG and protein abnormality, HIV-isolation, intrathecal anti HIV, exclusion of neurosyphilis and cryptococcal meningitis
• MRI: diffuse cerebral atrophy, ill-defined WM rarefaction.
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Ataxias

Movement disorders

Spinal cord diseases

Disorders of the neuromuscular junction

Myopathies

Demyelinating diseases

Autonomic disorders

Paroxysmal disorders

Systemic diseases and general medicine

Environmental neurology

Structural coma

Metabolic coma

Rehabilitation