Pathology Flashcards
Difference between paralysis, paresis, plegia, palsy
Paralysis: weakness so severe that muscle cannot be contracted
Paresis: weakness or partial paralysis
Plegia: severe weakness or paralysis
(Di-, hemi-, quadri-
Lower motor neuron syndrome
- Weakness/paralysis
- Atrophy
- Hypo or areflexia
- Decreased tone/flaccid paralysis
- Fibrillations (as measured by EMG)
EMG signs of denervation when muscle at rest
Fibrillation: short duration spontaneous biphasic or triphasic potentials produced by single muscle fibers, which are indicative of denervated muscle
Fasciculations: large potentials caused by spontaneous activity in one or several motor unit; large potentials suggest denervation and reinnervation
ALS
Degenerative disease of upper and lower motor neurons
Ventral horn involvement leads to lower motor neuron syndrome, while lateral corticospinal tract involvement leads to upper motor neuron syndrome
Loss of motor neurons in ventral horn cause fasciculations
No sensory loss.
Most are sporadic, but familial cases can be caused by a zinc-copper superoxide dismutase mutation (needed to bind free radicals)
Common causes of lower motor neuron syndrome
- Lesions in peripheral, spinal, or cranial nerves
- Lesions in cauda equina
- Strokes or tumors affecting alpha motor neurons in ventral horn or brainstem
- Polio
- ALS
- Guillain Barre
- Werdnig-Hoffman
Polio
Virus that affects alpha motor neuron’s ventral horn, so can lead to lower motor neuron syndrome
Can see period where patient is neurologically stable for years followed by progressive weakness in same muscles originally affected. This is because sprouting allows for recovery and stable period, but sprouts cannot be sustained.
Spinal Muscle Atrophy
Group of diseases caused by degeneration of anterior horns due to abnormalities in chromosome 5
Progressive disease that begins in infancy
4 types; first type is Werdnig-Hoffman
Affects motor neurons in the spinal cord and cranial nerve motor nuclei
Werdnig-Hoffman disease
Spinal Muscle Atrophy, Type I, inherited degeneration of anterior motor horn
Aka floppy baby
Autosomal recessive inheritance
Deadly
Symptoms:
Weakness and wasting in limb muscles, respiratory muscles, and bulbar muscles (as shown by sucking, swallowing, and breathing)
Upper Motor Neuron Lesions
Spinal shock followed by
- Paresis
- Hyper-reflexia
- Hypertonia
- Posturing
Variations on posturing with upper motor neuron syndrome
Decorticate when lesion above midbrain (upper limbs flexed, lower limbs extended)
Decerebrate when lesion below the midbrain (all limbs extended)
Babinski reflex
Indicates corticospinal tract lesion (upper motor neuron syndrome) if toes curl up (extensor plantar response) instead of down when lateral plantar surface is stroked
Normal in babies (before myelination)
Hoffman’s sign
Hold patient’s finger loosely and flick the fingernail downward, which should cause finger to rebound into extension.
If thumb flexes and adducts, it is positive Hoffman’s, indicated upper motor neuron syndrome
Bell’s Palsy
Paralysis of half the face due to lesion in CN VII
Common causes of upper motor neuron syndrome
Trauma
Stroke
MS
ALS
Cerebral Palsy
Non-progressive neurological disorder that appears in infancy or early child
Impacts body movement and muscle coordination; may cause intellectual disability
Can be caused by ischemia at birth, hypo-perfusion, trauma, or hemorrhage
Radiculopathy
Damage to spinal nerve, most commonly caused by herniated discs but also caused by osteophytes and spinal stenosis
Symptoms:
- Burning, tingling pain that radiates from back along a dermatome
- Numbness
- worsening of symptoms with coughing, sneezing, or straining; worsening of symptoms with flexing the head (in case of cervical radiculopathy)
- muscle weakness
Horner’s Syndrome
Interruption of sympathetic pathway to the head, eye, or neck caused by a lesion at T1 or above
Symptoms:
- miosis
- anhidrosis of face
- ptosis
Spinal shock
Spinal cord injury that causes immediate flaccid paralysis below the lesion
Usually lasts 1-6 weeks
Due to loss of descending facilitation that keep spinal cord circuits in continuous state of activation/readiness
WHO Grading System for Pathohistological Features of Tumors
I: curable with complete surgical resection
II: even complete resection may not be curative (~7-10 years)
III: not surgically curable; may kill on its own or up on version to grade IV (~3-7 years)
IV: not surgically curable; chemo/rad-to can extend life, but response is typically short-lived; quickly kills (~12-18 months)
Glioma
Tumor arising from glia
Pilocytic astrocytoma
Grade I/IV
Usually in kids, arising below tentorium
Cyst with nodule
Low grade, minimally infiltrative
Elongated cells with hairlike processes; Rosenthal fibers (thick eosinophilic processes)
GFAP+
Diffuse astrocytoma
Grade II, III, or IV
Irregular, elongated, crowded nuclei
GFAP+
Infiltrates normal brain to make surgical resection very difficult
The later the onset, the higher the grade
Glioblastoma
Astrocytoma
Grade IV
Most common malignant CNS tumor
Malignant, poorly differentiated tumor of glial cells
Application of receptor tyrosine kinases, proto-oncogenes (especially EGFR) which promotes its own growth
Butterfly lesion-crosses corpus callosum
May see microvascular proliferation or palisading necrosis (living cells at the edge of the necrosis)
GFAP+
Oligodendroglioma
Neoplasm of oligodendroglial cells Calcified tumor in white matter Grade II or III Usually in cerebral (frontal lobe) hemispheres Often hemorrhagic; causing seizures Genetics: co-deletion of 1p an 19q Fried egg nuclei May see chickenwire vasculature or calcifications
Ependymoma
Tumor of ependymal cells
Grade II or III
Usually in children beneath tentorium (4th ventricle)
Most common in 4th ventricle (very aggressive in children) or spinal cord (low grade and surgically treatable)
Perivascular pseduorosettes (tumor cells line up against blood vessels with pink material inbetween)
Pituitary adenoma
Low grade neuroendocrine tumor
Most common is a null-cell adenoma (not making hormones)
Most common hormone productions adenoma=protlactinoma
If it presses against optic chiasm can cause superior quadrantonopia
Prolactinoma-amenorrhea, galactorrhea
Growth hormone-acromegaly
ACTH-Cushing’s disease
Craniopharyngioma
Pituitary tumor in young kids
Supra tentorial in child and adult
Can cause inferior quadrantonopia
Derived from remnants of Rathke’s pouch (origin of anterior pituitary)
See squamous epi, “wet keratin”, and cholesterol clefts
Look at root of word!! Crani-, pharyng-
Calcifications seen on imagining
Schwannoma
Benign tumor; Grade I
Caused by bi-allergic inactivation of NF2 gene
Symptoms caused by compression of nerves, particularly vestibular nerve, which made lead to tinnitus and deafness
Bland-spindle shaped cells
Hypercellular=Antoni A
Hypocellular=Antoni B
Verocay bodies=nuclei lining up together
especially at cerebellar pontine angle, involving CN8.
S100+
Meningioma
Dural based tumor of meningothelial cells
Will see dural tail on MRI
Grade I-III
50% have NF2 mutation
Histo shows whorls and calcifications (psammomatous)
Most common benign tumor
Tumor expresses estrogen receptor; more common in women
Hemangioblastoma
Grade I lesion
Occurs from mutation in VHL, allowing for constitutive activation of HIF
Usually occurs in cerebellum, but also seen in spine, brainstem, and retina
Histo: foamy cells and dense capillary network
Medulloblastoma
Grade IV Derived form neuroectodermal tissue Most common malignant tumor in children Tumor of primitive neurons Synaptophysin+ In cerebellar/posterior fossa True (Homer-Wright) rosettes
Analgesia
Los of pain sensation
Anesthesia
Loss of touch sensation
Paresthesias
Temporary mild pain
Neuropathic pain/central pain syndrome
Chronic intense pain
Tabes Dorsalis
Caused by tertiary syphilis infection leading to degeneration of dorsal columns
Symptoms: impaired sensation, propioception, and progressive sensory ataxia
Subacute combined degeneration of dorsal columns and spinocerebellar tract from vitamin B12 or E deficiency
Causes demyelination of dorsal columns, lateral corticospinal tracts, and spinocerebrallar tracts causing ataxic gait, paresthesia, and impaired position and vibration sense
Brown-Sequard Syndrome
Hemiplegia caused by damage to one half of spinal cord resulting in loss of ipsilateral proprioception and contralateral pain/temperature loss
Phantom Limb
Reorganization of somatosensory cortex in amputees causing neurons that were innervated by the limb no respond to stimulation of other body parts.
Syringomyelia
Cystic degeneration of the spinal cord due to trauma or associated with Arnold Chiari malformation
Usually at C8-T1, causing “cape or shawl” pattern loss of pain and temperature (due to knock out of white commissure), but spares fine touch and proprioception
Syrinx can expand to knock out ventral and lateral horn (affecting motor and sympathetic systems; causing Horner syndrome and lower motor neuron syndrome)
Friedeich Ataxia
Degenerative disorder of the cerebellum and spinal cord tract presenting as ataxia with loss of vibratory sense, propioception, muscle weakness in lower extremities, and loss of reflex
Autosomal recessive, characterized by trinucleotide repeat in frataxin gene (needed for mitochondrial iron regulation)
present in early childhood
Can present as hypertrophic cardiomyopathy.
Dejerine Roussy Syndrome
Lesion of thalamus causing contralateral burning pain
Diabetes
Reduced blood supply to peripheral nerves is cause of sensory neuropathy
Usually in glove and stocking pattern (polyneuropathy), but sometimes acute mononeuopathy
Small fibers most affected
Fascicles show decreased number of myelinated and unmyelinated axons and thickening of walls of blood vessels.
Symptoms begin in feet, then move more proximal legs and distal upper limbs
Symptoms: paresthesia, dysesthias, numbness, tingling, burning
Sometimes there is motor weakness in distal limbs
Guillain-Barre
Aka acute inflammatory demyelinating polyneuropathy
Acute inflammatory attack on peripheral myelin following a viral infection
Causes demyelination and polyneuropathy leading to motor symptoms
Decreased nerve conduction velocity and increased protein in CSF
Treat with plasmapheresis or IV immunoglobulin therapy
Wallerian degeneration
When nerve fiber is injured, causing degeneration of the axon distal to the injury
May cause sensory neuropathy
Herpes Zoster
Infection of dorsal root ganglion that produces sensory symptoms in corresponding dermatome
Increases excitability of sensory neurons in dorsal root ganglion causing lowering of threshold and spontaneous firing
Pain sensation will be in dermatomal distribution (usually thoracic; but in immunocomprised, can infect CN V)
Treat with antivirals (acyclovir, valcylovir, famcyclovir)
Can still have pain after rash has subsided
TORCHeS
Congenital insensitivity to pain
Recessive mutation in pain receptor Nav 1.7 that cases loss of function of pain
Inherited erythromelagia
Dominant mutation causing gain of function pain sensation (so experience increased pain) in temperature
Paroxysmal extreme pain disorder
Dominant mutation in Nav1.7 causing increased pain around the mouth and anus
Hyperalgesia
Sensitization pathway: When stimuli that are normally considered slightly painful are now significantly more painful
Allodynia
The induction of pain by what is normally an non-painful stimulus
Neuropathic pain
Pain that develops as a result of damage to the nervous system
Can manifest as burning, shooting, or stinging pain mixed with numbness
May include changes in pain threshold, quality of pain, and spontaneous pain
Treated with antidepressants and anti-epileptic drugs
B12 Deficiency
Most common metabolic neuropathy
Can affect peripheral nerves, optic nerves, spinal cord, and brain
Symptoms include distal limbs, usually starting in upper limb
Dorsal columns are most affected; loss of sense of vibration. Followed by corticospinal.
Decrease in nerve conduction velocity
May see ataxia and spasticity if it has caused subacute combined degeneration
Charcot Marie Tooth
Hereditary motor and sensory neuropathy
CMT1 is the most common, causing motor sensory neuropathy primarily affecting distal muscles
Slow progressive
Decreased NCV
Onion bulb appearance due to constant demyelination and remyelination
Papilledema
Swelling of optic disk due to increased ICP, impairing venous return
Usually bilateral
Acute or longer onset
Scotoma
Smaller visual loss
Anopia
Loss of entire eye visual field
Potential effect of internal carotid aneurysm
If expanding medially, could press against lateral part of optic chiasm, causing nasal field loss in one eye
Middle cerebral branch aneurysm affecting temporal lobe can cause
Meyer’s loop lesion, “pie in the sky” vision loss
Middle cerebral branch aneurysm affecting parietal lobe can cause
Optic radiation lesion, “pie on the floor” vision loss
Lesion before optic chiasm
Defects are ipsilateral and monocular
Lesion at optic chiasm
Defects are binocular, bitemporal, heteronymous
Lesion past optic chiasm
Defects are binocular, contralateral, homonymous
Lesion with abnormal pupillary reflex
Optic nerve and optic tract lesion
Lesion with normal pupillary reflex
Optic radiation and visual cortex lesions
Posterior cerebral artery infarct
Would affect primary visual cortex in occipital lobe
Contralateral homonymous hemianopia WITH MACULAR SPARING
Lesion to occipital pole
Macular visual field defect
Macular degeneration
Age related vision loss due to deposition of fatty tissue behind the retina (dry macular degeneration) or neovascularization of the retina (wet macular degeneration)
Lose vision in the middle of the eye due to macular loss
Prosopagnosia
Damage to fusiform gyrus causing inability to recognize people by looking at their faces
Damage specifically to area dedicated to face
Most commonly caused by closed head trauma or bilateral stroke
Cortical blindness
Caused by lesion in V1 affecting all visual inputs
Apperceptive Agnosia
Lesion in V2/V3 can affect combination of form and shape inputs (can’t copy letters or shapes patient sees)
Achromatopsia
Inability to see color because of a lesion in V4
Akinetopsia
Inability to see motion because of lesion in V5
Static items are visual but disappear once they start moving
Slow moving objects may be detected, but direction of motion may not be obvious
Glaucoma
excess aqueous humor leads to optic nerve damage, ocular hypertension, and visual field loss
Managed with beta blockers (block ciliary epithelium from producing aqueous humor)
Sometimes requires surgery
Conjunctivitis
inflammation of conjunctiva, usually bilateral and due to viral infection; can also be caused by bacterial infection, allergy, or autoimmune condition
