PNS Pathology Flashcards
(56 cards)
Branches of the Sciatic nerve
1) Tibial Nerve
2) Common peroneal nerve (becomes superficial and deep)
What is the result of damage to the tibial nerve?
1) Loss of plantar felxion (due to innervation of gastrocnemius, soleus, ect)
2) Loss of inversion (due to innervation of the tibialis posterior)
3) Provides sensory innervation for the plantar surface of the foot
Branches of the Brachial plexus
1) Musculoskeletal (C5-7)
2) Axillary (C5-6)
3) Median (C6-T1)
4) Ulnar (C8-T1)
5) Radial (C5-8)
Parts of the Brachial Plexus
1) Roots
2) Trunks
3) Division
4) Cords
5) Branches
What causes segmental demyelination of peripheral neurons?
1) Damage to the Schwann cell
2) Damage to the myelin sheath
What is a result of axonal degeneration?
1) Denervation atrophy
What is the morphology of denervation atrophy?
1) Decreased muscle fiber size
2) Fibers have a triangular shape
3) Round zone of disorganized myofibers in the center of the cell (target fiber)
Inflammation and segmental demyelination of spinal nerve roots and peripheral nerves due to an immune mediated process
Guillain-Barre Syndrome
What is the dominant histopathologic finding in Guillan-Barre Syndrome?
1) Inflammation of the peripheral nerve
2) Most intense inflammation occurs at the spinal cord and cranial roots
What is the earliest manifestation of Diphtheria in regards to neurologic symptoms?
1) Loss of sensory ganglia due to the incomplete blood brain barrier
2) Loss of proprioception and vibratory sense
What does myobacterium leprae infect in the nervous system? What type of leprosy is worse?
1) Infect the Schwann cells and cause demylination
2) Lepromatous leprosy
What cells are active in lepromatous leprosy? tuberculoid leprosy?
1) TH2
2) TH1 (activate macrophages)
Reactive infection that results in painful, vesicular skin eruptions in the distribution of the sensory dermatomes in the thoracic and trigeminal region
Varicella-Zoster virus
What is another name for Hereditary Motor and Sensory Neuropathy Type I?
Charcot-Marie-Tooth disease
What are findings of Charcot-Marie-Tooth Disease?
1) Progressive muscular atrophy of the leg below the knee
2) Pes cavus
What are causes for Charcot-Maire-Tooth disease (Type 1A and B)
1) Type 1A = segmental trisomy of chromosome 17
2) Type 1B = mutation of MPZ gene on chromosome 1
What are the Hereditary Neuropathies?
1) Charcot-Marie-Tooth Disease (HMSN type I)
2) HMSN type II
3) Dejerine-Sottas Neuropahty (HMSN type III)
What is hypertrophic neuropahty?
1) Enlargement of peripheral nerves due to layers of schwann cell hyperplasia
2) Occurs in hereditary demyelinating diseases
Slowly progressive autosomal recessive hereditary neuropathy that presents with delay of developmental milestones, absent DTRs and trunk/limb atrophy; Loss of axons
Dejerine-Sottas Neuropahty
What is the most common clinicopathologic pattern of peripheral neuropathy found in Adult onset diabetes?
1) Distal symmetric sensory and motor neuropathy
What are the common presentations observed in Diabetic patients neurologically?
1) Distal symmetric sensory and motor neuropathy
2) Loss of pain sensation
3) Loss of motor function
4) Autonomic dysfunction such as postural hypotension, sexual dysfunction, and failure to completely empty the bladder
What vitamin deficiencies result in axonal neuropathies?
1) Thiamine (B1)
2) B6
3) B12
4) Vitamin E
What is the cause of a traumatic neuroma (pseudoneuroma)?
1) the growth of an axon after trauma that does not have a correctly positioned distal segment
What is Myasthenia gravis commonly associated with?
1) Thymoma
2) Thymus hyperplasia
