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Flashcards in Pathology Deck (75):
1

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-

2

Lower motor neuron syndrome

1. Weakness/paralysis
2. Atrophy
3. Hypo or areflexia
4. Decreased tone/flaccid paralysis
5. Fibrillations (as measured by EMG)

3

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

4

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)

5

Common causes of lower motor neuron syndrome

1. Lesions in peripheral, spinal, or cranial nerves
2. Lesions in cauda equina
3. Strokes or tumors affecting alpha motor neurons in ventral horn or brainstem
4. Polio
5. ALS
6. Guillain Barre
7. Werdnig-Hoffman

6

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.

7

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

8

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)

9

Upper Motor Neuron Lesions

Spinal shock followed by
1. Paresis
2. Hyper-reflexia
3. Hypertonia
4. Posturing

10

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)

11

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)

12

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

13

Bell's Palsy

Paralysis of half the face due to lesion in CN VII

14

Common causes of upper motor neuron syndrome

Trauma

Stroke

MS

ALS

15

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

16

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

17

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

18

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

19

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)

20

Glioma

Tumor arising from glia

21

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+

22

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

23

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+

24

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

25

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)

26

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

27

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

28

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+

29

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

30

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

31

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

32

Analgesia

Los of pain sensation

33

Anesthesia

Loss of touch sensation

34

Paresthesias

Temporary mild pain

35

Neuropathic pain/central pain syndrome

Chronic intense pain

36

Tabes Dorsalis

Caused by tertiary syphilis infection leading to degeneration of dorsal columns

Symptoms: impaired sensation, propioception, and progressive sensory ataxia

37

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

38

Brown-Sequard Syndrome

Hemiplegia caused by damage to one half of spinal cord resulting in loss of ipsilateral proprioception and contralateral pain/temperature loss

39

Phantom Limb

Reorganization of somatosensory cortex in amputees causing neurons that were innervated by the limb no respond to stimulation of other body parts.

40

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)

41

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.

42

Dejerine Roussy Syndrome

Lesion of thalamus causing contralateral burning pain

43

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

44

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

45

Wallerian degeneration

When nerve fiber is injured, causing degeneration of the axon distal to the injury

May cause sensory neuropathy

46

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

47

Congenital insensitivity to pain

Recessive mutation in pain receptor Nav 1.7 that cases loss of function of pain

48

Inherited erythromelagia

Dominant mutation causing gain of function pain sensation (so experience increased pain) in temperature

49

Paroxysmal extreme pain disorder

Dominant mutation in Nav1.7 causing increased pain around the mouth and anus

50

Hyperalgesia

Sensitization pathway: When stimuli that are normally considered slightly painful are now significantly more painful

51

Allodynia

The induction of pain by what is normally an non-painful stimulus

52

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

53

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

54

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

55

Papilledema

Swelling of optic disk due to increased ICP, impairing venous return

Usually bilateral

Acute or longer onset

56

Scotoma

Smaller visual loss

56

Anopia

Loss of entire eye visual field

57

Potential effect of internal carotid aneurysm

If expanding medially, could press against lateral part of optic chiasm, causing nasal field loss in one eye

58

Middle cerebral branch aneurysm affecting temporal lobe can cause

Meyer's loop lesion, "pie in the sky" vision loss

59

Middle cerebral branch aneurysm affecting parietal lobe can cause

Optic radiation lesion, "pie on the floor" vision loss

60

Lesion before optic chiasm

Defects are ipsilateral and monocular

61

Lesion at optic chiasm

Defects are binocular, bitemporal, heteronymous

62

Lesion past optic chiasm

Defects are binocular, contralateral, homonymous

63

Lesion with abnormal pupillary reflex

Optic nerve and optic tract lesion

64

Lesion with normal pupillary reflex

Optic radiation and visual cortex lesions

65

Posterior cerebral artery infarct

Would affect primary visual cortex in occipital lobe

Contralateral homonymous hemianopia WITH MACULAR SPARING

66

Lesion to occipital pole

Macular visual field defect

67

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

68

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

69

Cortical blindness

Caused by lesion in V1 affecting all visual inputs

70

Apperceptive Agnosia

Lesion in V2/V3 can affect combination of form and shape inputs (can't copy letters or shapes patient sees)

71

Achromatopsia

Inability to see color because of a lesion in V4

72

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

73

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

74

Conjunctivitis

inflammation of conjunctiva, usually bilateral and due to viral infection; can also be caused by bacterial infection, allergy, or autoimmune condition