Neuromuscular junction disorders: Pathology review


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Neuromuscular junction disorders: Pathology review

Musculoskeletal system

Pediatric musculoskeletal conditions

Radial head subluxation (Nursemaid elbow)

Developmental dysplasia of the hip

Legg-Calve-Perthes disease

Slipped capital femoral epiphysis

Transient synovitis

Osgood-Schlatter disease (traction apophysitis)

Musculoskeletal injuries and trauma

Rotator cuff tear

Dislocated shoulder

Radial head subluxation (Nursemaid elbow)

Winged scapula

Thoracic outlet syndrome

Carpal tunnel syndrome

Ulnar claw

Erb-Duchenne palsy

Klumpke paralysis

Iliotibial band syndrome

Unhappy triad

Anterior cruciate ligament injury

Patellar tendon rupture

Meniscus tear

Patellofemoral pain syndrome

Sprained ankle

Achilles tendon rupture



Degenerative disc disease

Spinal disc herniation


Compartment syndrome


Bone disorders

Osteogenesis imperfecta


Pectus excavatum


Genu valgum

Genu varum

Pigeon toe

Flat feet

Club foot

Cleidocranial dysplasia



Bone tumors




Osteomalacia and rickets


Paget disease of bone


Lordosis, kyphosis, and scoliosis

Joint disorders



Spinal stenosis

Rheumatoid arthritis

Juvenile idiopathic arthritis


Calcium pyrophosphate deposition disease (pseudogout)

Psoriatic arthritis

Ankylosing spondylitis

Reactive arthritis


Septic arthritis


Baker cyst

Muscular disorders

Muscular dystrophy



Inclusion body myopathy

Polymyalgia rheumatica



Neuromuscular junction disorders

Myasthenia gravis

Lambert-Eaton myasthenic syndrome

Other autoimmune disorders

Sjogren syndrome

Systemic lupus erythematosus

Mixed connective tissue disease

Antiphospholipid syndrome

Raynaud phenomenon


Limited systemic sclerosis (CREST syndrome)

Musculoskeletal system pathology review

Back pain: Pathology review

Rheumatoid arthritis and osteoarthritis: Pathology review

Seronegative and septic arthritis: Pathology review

Gout and pseudogout: Pathology review

Systemic lupus erythematosus (SLE): Pathology review

Scleroderma: Pathology review

Sjogren syndrome: Pathology review

Bone disorders: Pathology review

Bone tumors: Pathology review

Myalgias and myositis: Pathology review

Neuromuscular junction disorders: Pathology review

Muscular dystrophies and mitochondrial myopathies: Pathology review


Neuromuscular junction disorders: Pathology review

USMLE® Step 1 questions

0 / 7 complete


USMLE® Step 1 style questions USMLE

of complete

A 65-year-old man comes to his outpatient provider because of a chronic cough for the past 3 months. It is occasionally accompanied by flecks of blood-tinged sputum. Review of systems is significant for weakness in the hips and thighs bilaterally and 15 lbs (6.8 kg) weight loss. Past medical history is notable for hypertension. He only takes hydrochlorothiazide. Social history is notable for a 50-pack-year smoking history. In the office, his temperature is 37.0°C (98.6°F), pulse is 76/min and blood pressure is 157/85 mmHg. Pulmonary examination reveals expiratory wheezing on the left side in 5th intercostal space. A chest radiograph is ordered and reveals the following:

Reproduced from:   

Laboratory testing reveals a creatinine kinase level of 75 U/L. Which of the following additional examination findings will most likely be present in this patient?  


Content Reviewers


Daniel Afloarei, MD

Sam Gillespie, BSc

Tanner Marshall, MS

Kaia Chessen, MScBMC

While doing your rounds, you see Kira, a 23-year-old female who presents with a series of recurrent symptoms that get worse as the day progresses. These include slurring of speech, difficulty swallowing, and double vision. She also mentions that her head feels heavy and is hard to hold up. She also complained that her arms are so weak she can’t even brush her hair. Additionally, she reports severe fatigue and shortness of breath. On examination, sensation and reflexes are normal. Next, you see a 62-year-old man named Jonathan, who presents with a history of leg muscle weakness that prevents him from doing simple things like climbing stairs or standing up, which gets better the more he uses his legs. He also reports shortness of breath, fatigue, dry mouth, impotence, and unintentional weight loss. Examination reveals a severely underweight man with dilated pupils. Reflexes are initially absent, although these are obtainable after a brief period of exercise. Blood tests were obtained, detecting anti-acetylcholine receptor antibodies in Kira and anti-voltage-gated calcium channels antibodies in Jonathan.

Now, both seem to have some type of neuromuscular junction disease. But first, a bit of physiology. In normal neuromuscular function, a nerve impulse is carried down the axon from the spinal cord, to the nerve endings, in the neuromuscular junction, where the impulse is transferred to the muscle cell. Here, the nerve impulse leads to the opening of voltage-gated calcium channels, causing an influx of calcium ions into the nerve terminal, which triggers synaptic vesicle fusion with plasma membrane. These synaptic vesicles contain a neurotransmitter called acetylcholine, which is released into the synaptic cleft. The neurotransmitter then binds to nicotinic acetylcholine receptors on muscle cell membranes and activates a chain reaction in the muscles that ultimately results in their contraction.


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