Provide 30 mcqs pattern exam without answers on the topic of PNS based on Robins and cotran latest edition.difficulty level is moderate level. Note:also use my file as reference as well.

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python3 -c " import pdfplumber with pdfplumber.open('/tmp/workspace/attachments/0df28b71-b6ca-4e2f-bb6d-264a44bdde09/lecture_INST-100321_2026_06_27_09_33_29.pdf') as pdf: print(f'Total pages: {len(pdf.pages)}') for i, page in enumerate(pdf.pages): text = page.extract_text() if text: print(f'--- PAGE {i+1} ---') print(text[:3000]) if i >= 8: print('... truncated for preview ...') break "

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python3 -c " import pdfplumber with pdfplumber.open('/tmp/workspace/attachments/0df28b71-b6ca-4e2f-bb6d-264a44bdde09/lecture_INST-100321_2026_06_27_09_33_29.pdf') as pdf: print(f'Total pages: {len(pdf.pages)}') all_text = [] for i, page in enumerate(pdf.pages): text = page.extract_text() if text: all_text.append(f'--- PAGE {i+1} ---\n{text}') full = '\n'.join(all_text) print(full) " 2>&1 | head -500

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The medical library database appears to be experiencing errors. I have the full content from the lecture PDF and my knowledge of Robbins & Cotran. I'll now generate the 30 MCQs.

30 MCQs on Peripheral Nervous System (PNS) Pathology

Based on Robbins & Cotran Pathologic Basis of Disease (Latest Edition) + Lecture Reference Difficulty: Moderate

Q1. The morphologic hallmark of axonal neuropathy is:

A) Onion-bulb formation B) Wallerian degeneration C) Segmental demyelination D) Perifascicular atrophy E) Neuronophagia

Q2. In Wallerian degeneration, which of the following changes occurs FIRST in the distal nerve segment?

A) Schwann cell proliferation B) Axonal fragmentation and myelin breakdown C) Macrophage infiltration of endoneurium D) Regeneration sprouts from node of Ranvier E) Fibrosis of the endoneurial tube

Q3. Repaired Schwann cells after demyelinating injury tend to be:

A) Longer and thicker than original B) Identical in size to the original C) Shorter and thinner than the original D) Replaced entirely by fibroblasts E) Identical in internodal length but doubled in thickness

Q4. A patient presents with ascending paralysis, areflexia, and elevated CSF protein with normal cell count (albuminocytologic dissociation). The underlying pathology is best described as:

A) Axonal degeneration of anterior horn cells B) Immune-mediated demyelination of roots and peripheral nerves C) Vasculitic ischemia of multiple nerves D) Toxin-mediated neuromuscular blockade E) Compression of the spinal cord at cervical level

Q5. Guillain-Barré syndrome is classified pathologically as:

A) Axonal neuronopathy B) Vasculitic mononeuritis multiplex C) Acute inflammatory demyelinating polyradiculoneuropathy D) Chronic axonal polyneuropathy E) Toxic segmental demyelination

Q6. Chronic Inflammatory Demyelinating Polyneuropathy (CIDP) is characterized by all of the following EXCEPT:

A) Symmetric mixed sensorimotor polyneuropathy B) Subacute or chronic course with relapses and remissions C) Responsiveness to corticosteroids D) Predominantly axonal degeneration on biopsy E) Recurrent demyelination and remyelination with onion-bulb changes

Q7. Mononeuritis multiplex is most characteristically associated with which of the following conditions?

A) Diabetic peripheral neuropathy B) Guillain-Barré syndrome C) Vasculitis D) Leprosy (lepromatous type) E) Hereditary motor-sensory neuropathy

Q8. In lepromatous leprosy, the peripheral nerve pathology is best described as:

A) Granulomatous inflammation with localized nerve destruction B) Segmental demyelination and remyelination causing symmetric polyneuropathy C) Axonal loss predominantly in proximal nerve roots D) Vasculitic ischemia of the vasa nervorum E) Purely sensory neuronopathy with dorsal root ganglia involvement

Q9. In tuberculoid leprosy involving peripheral nerves, the histologic finding is:

A) Foamy macrophages filled with Mycobacterium leprae B) Segmental demyelination without inflammation C) Granulomatous inflammation in dermal nerve twigs D) Diffuse endoneurial fibrosis E) Perivascular eosinophilic infiltration

Q10. Varicella-Zoster Virus maintains latency in the peripheral nervous system within:

A) Schwann cells of motor nerves B) Neurons of sensory ganglia (dorsal root ganglia) C) Satellite cells of sympathetic ganglia D) Endoneurial fibroblasts E) Perineurial cells

Q11. The most common cause of peripheral neuropathy worldwide is:

A) Guillain-Barré syndrome B) Chronic alcohol use C) Diabetes mellitus D) Leprosy E) Vitamin B12 deficiency

Q12. Early-stage HIV infection is most characteristically associated with which pattern of peripheral neuropathy?

A) Painful distal sensory polyneuropathy B) Mononeuritis multiplex and demyelinating disorders C) Symmetric motor-predominant polyneuropathy D) Polyradiculoneuropathy with bowel/bladder dysfunction E) Autonomic neuropathy with postural hypotension

Q13. Diphtheria causes peripheral neuropathy through which primary mechanism?

A) Direct invasion of peripheral nerve by Corynebacterium diphtheriae B) Toxin-mediated demyelination causing bulbar and respiratory muscle dysfunction C) Autoimmune attack on AChR at neuromuscular junction D) Vasculitis of vasa nervorum E) Axonal degeneration due to thiamine deficiency

Q14. Lyme disease involving the peripheral nervous system most typically presents as:

A) Symmetric distal sensorimotor polyneuropathy B) Polyradiculoneuropathy and facial nerve palsy C) Mononeuritis multiplex due to vasculitis D) Demyelinating polyneuropathy indistinguishable from GBS E) Autonomic neuropathy with cardiac involvement only

Q15. The autoantibody in Myasthenia Gravis is directed against:

A) Voltage-gated calcium channels at presynaptic terminal B) Acetylcholine receptors (AChRs) at the postsynaptic membrane C) Acetylcholinesterase at the neuromuscular junction D) Muscle-specific receptor tyrosine kinase (MuSK) exclusively E) Voltage-gated potassium channels

Q16. Which of the following best distinguishes Lambert-Eaton Myasthenic Syndrome (LEMS) from Myasthenia Gravis?

A) LEMS is associated with anti-AChR antibodies B) Muscle weakness in LEMS improves with repeated stimulation C) LEMS predominantly affects ocular muscles D) LEMS is never paraneoplastic in etiology E) LEMS is autosomal dominant in inheritance

Q17. Botulism produces weakness by:

A) Binding and blocking acetylcholine receptors postsynaptically B) Inhibiting acetylcholinesterase C) Blocking acetylcholine release from presynaptic neurons D) Destroying motor neurons in anterior horn E) Demyelinating peripheral motor nerves

Q18. A patient with known small cell lung carcinoma develops proximal lower extremity weakness that improves transiently with exercise and is associated with autonomic dysfunction. The most likely autoantibody target is:

A) Acetylcholine receptors (AChR) B) Voltage-gated calcium channels (VGCC) C) Voltage-gated potassium channels D) NMDA receptors E) Anti-Hu (ANNA-1)

Q19. On muscle biopsy, groups of atrophic fibers arranged in angular clusters are characteristic of:

A) Primary myopathy B) Neurogenic injury with denervation atrophy C) Inflammatory myopathy D) Disuse atrophy E) Congenital myopathy

Q20. Dermatomyositis is distinguished from polymyositis histologically by:

A) Presence of cytotoxic T cells invading non-necrotic fibers B) Perifascicular atrophy of muscle fibers and perivascular inflammation C) Rimmed vacuoles and tubulofilamentous inclusions in fibers D) Absence of inflammatory infiltrate E) Eosinophilic infiltration of the endomysium

Q21. Anti-Jo-1 antibody in dermatomyositis is directed against:

A) A helicase involved in nucleosome remodeling B) Histidyl tRNA synthetase C) Several transcriptional regulators D) Acetylcholine receptor E) Voltage-gated calcium channel

Q22. Inclusion body myositis typically shows all of the following EXCEPT:

A) Onset predominantly in patients over 50 years B) Distal muscle involvement (especially quadriceps and distal upper extremities) C) Response to immunosuppressive therapy D) Rimmed vacuoles on muscle biopsy E) Cytotoxic T-cell mediated muscle damage

Q23. Duchenne Muscular Dystrophy (DMD) is caused by a mutation in the gene encoding:

A) Dystroglycan B) Sarcoglycan C) Dystrophin (Xp21) D) Myosin heavy chain E) Laminin alpha-2 (merosin)

Q24. Which of the following statements correctly differentiates Becker Muscular Dystrophy (BMD) from Duchenne Muscular Dystrophy (DMD)?

A) BMD is caused by a different gene than DMD B) BMD has absent dystrophin; DMD has reduced dystrophin C) BMD is more severe with earlier onset than DMD D) BMD has reduced or truncated dystrophin with later onset and slower progression E) BMD follows autosomal recessive inheritance unlike DMD

Q25. Myotonic dystrophy is caused by:

A) Deletion of the dystrophin gene on Xp21 B) CTG trinucleotide repeat expansion on chromosome 19q13 affecting DMPK mRNA C) Overexpression of DUX4 gene on chromosome 4q35 D) Point mutation in the chloride channel gene E) CAG repeat expansion on chromosome 3

Q26. Facioscapulohumeral muscular dystrophy (FSHD) is characterized by:

A) X-linked recessive inheritance with absent dystrophin B) Autosomal dominant inheritance with overexpression of DUX4 gene C) CTG repeat expansion with myotonia D) Loss-of-function mutation in the SMN1 gene E) Autosomal recessive inheritance with peroneal muscle involvement

Q27. Spinal Muscular Atrophy (SMA) is caused by:

A) Gain-of-function mutation in SMN2 gene B) Loss-of-function mutations in the SMN1 gene C) CTG repeat expansion in DMPK gene D) Deletion of dystrophin gene E) Mutation in NF1 gene

Q28. A schwannoma is characterized by all of the following EXCEPT:

A) Arising directly from peripheral nerve Schwann cells B) Loss of merlin expression (NF2 gene product) C) Admixture of Antoni A (dense) and Antoni B (loose) areas on histology D) Transformation to malignant peripheral nerve sheath tumor (MPNST) E) Also known as acoustic neuroma when at cranial nerve VIII

Q29. Neurofibromas differ from schwannomas in that neurofibromas:

A) Arise exclusively from Schwann cells with no other cell types B) Show Antoni A and Antoni B patterns on histology C) Contain an admixture of Schwann cells, perineural-like cells, fibroblasts, mast cells, and CD34+ spindle cells D) Never transform to malignancy E) Are always associated with NF2 gene mutations

Q30. Neurofibromatosis Type 2 (NF2) is correctly described by which of the following?

A) Autosomal dominant disorder caused by loss-of-function mutations in the NF1 gene B) Characterized by cafe-au-lait spots and Lisch nodules C) Rare autosomal dominant disorder with bilateral eighth-nerve schwannomas, meningiomas, and spinal ependymomas due to NF2 gene (merlin) mutations D) Most common form of neurofibromatosis with plexiform neurofibromas E) Associated with pheochromocytoma and optic glioma as primary features

Reference: Robbins & Cotran Pathologic Basis of Disease, 10th Edition - Chapter on Peripheral Nerve and Skeletal Muscle; supplemented by provided lecture material (CDL PNS Lecture, 2026)

B A C B C E C B C B C B B D C B C B B B B C C D B B B D C C Check out the answers carefully and provide correct answers. Passing score is 15 out of 30

I'll carefully evaluate each answer against the correct answer key from Robbins & Cotran and the lecture material.

Here is the full evaluation:

Answer Key & Score Sheet

Q#	Your Answer	Correct Answer	Result	Explanation
1	B	B	✅	Wallerian degeneration is the morphologic hallmark of axonal neuropathy
2	A	B	❌	FIRST event is axonal fragmentation and myelin breakdown, not Schwann cell proliferation
3	C	C	✅	Repaired Schwann cells are shorter and thinner
4	B	B	✅	GBS = immune-mediated demyelination of roots and peripheral nerves
5	C	C	✅	GBS = Acute inflammatory demyelinating polyradiculoneuropathy
6	E	D	❌	The EXCEPTION is D - CIDP shows demyelination (not predominantly axonal degeneration); onion-bulb changes ARE a feature of CIDP
7	C	C	✅	Vasculitis is the classic cause of mononeuritis multiplex
8	B	B	✅	Lepromatous leprosy = segmental demyelination causing symmetric polyneuropathy
9	C	C	✅	Tuberculoid leprosy = granulomatous inflammation in dermal nerve twigs
10	B	B	✅	VZV is latent in neurons of sensory ganglia (DRG)
11	C	C	✅	Diabetes mellitus is the most common cause of peripheral neuropathy
12	B	B	✅	Early HIV = mononeuritis multiplex and demyelinating disorders
13	B	B	✅	Diphtheria = toxin-mediated demyelination with bulbar/respiratory dysfunction
14	D	B	❌	Lyme disease = polyradiculoneuropathy and facial nerve palsy (bilateral); not GBS-like demyelination
15	C	B	❌	MG antibodies are against AChR (postsynaptic). Option C describes acetylcholinesterase inhibition, which is a treatment mechanism, not the autoantibody target
16	B	B	✅	LEMS improves with repeated stimulation (unlike MG which fatigues)
17	C	C	✅	Botulinum toxin blocks ACh release from presynaptic neurons
18	B	B	✅	LEMS paraneoplastic = anti-VGCC antibodies (small cell lung ca)
19	B	B	✅	Angular atrophic fiber clusters = neurogenic/denervation atrophy
20	B	B	✅	Dermatomyositis = perifascicular atrophy + perivascular inflammation
21	B	B	✅	Anti-Jo1 = histidyl tRNA synthetase
22	C	C	✅	Inclusion body myositis does NOT respond to immunosuppressive therapy
23	C	C	✅	DMD = dystrophin gene mutation at Xp21
24	D	D	✅	BMD = reduced/truncated dystrophin, later onset, slower progression
25	B	B	✅	Myotonic dystrophy = CTG repeat expansion on Ch19q13 affecting DMPK
26	B	B	✅	FSHD = autosomal dominant, DUX4 overexpression
27	B	B	✅	SMA = LOF mutations in SMN1 gene
28	D	D	❌	The EXCEPTION is D - it is NEUROFIBROMAS (not schwannomas) that transform to MPNST. Schwannomas rarely undergo malignant transformation
29	C	C	✅	Neurofibromas = admixture of Schwann cells, perineural-like cells, fibroblasts, mast cells, CD34+ spindle cells
30	C	C	✅	NF2 = autosomal dominant, bilateral 8th nerve schwannomas, NF2/merlin mutations

Score Summary

	Count
✅ Correct	25
❌ Incorrect	5
Total Score	25 / 30

Result: ✅ PASS (Passing score: 15/30)

You scored 25/30 (83.3%) — well above the passing threshold.

Review of Incorrect Answers

Q2 - The first event in Wallerian degeneration is axonal fragmentation and myelin breakdown (B), not Schwann cell proliferation. Schwann cells proliferate later to form Bands of Büngner as part of the repair phase.

Q6 - The EXCEPTION in CIDP is D (predominantly axonal degeneration). CIDP is a demyelinating disorder. Onion-bulb changes from recurrent demyelination/remyelination are actually a hallmark feature of CIDP, so option E is not the exception.

Q14 - Lyme disease classically causes polyradiculoneuropathy and facial nerve palsy (B), which is the direct textbook statement from Robbins and your lecture slide. Option D (GBS-like demyelination) would not specifically describe Lyme neuropathy.

Q15 - MG autoantibodies target acetylcholine receptors (AChR) at the postsynaptic membrane (B). Note that some patients have anti-MuSK antibodies as an additional/alternative target, but the primary/classic autoantibody remains anti-AChR. Option C describes inhibition of acetylcholinesterase, which is the mechanism of pyridostigmine treatment, not the autoimmune target.

Q28 - The EXCEPTION for schwannoma is D. It is neurofibromas that carry significant risk of transformation to Malignant Peripheral Nerve Sheath Tumor (MPNST), not schwannomas. Schwannomas are typically benign with very rare malignant transformation.

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