PATHOLOGY EXAM 4: MYOPATHY I EXAM
2025/2026 QUESTIONS WITH ANSWERS GRADED
A+
Atrophy - decrease in size or wasting away of tissue
Example of Inflammatory-Autoimmune Disorders - Myositis
Contenital Myopathy - Any myopathy present at birth
Leads to weakness in skeletal muscle
6 in 100,000 live births
Metabolic myopathy - Genetic defects with release of ATP and energy generating relating to
muscle
Myopathy - Disease of muscle tissue
2 types of atrophy - Disuse
Neurogenic
Disuse atrophy - lack of exercise
can be reversed
Neurogenic atrophy - Injury to a nerve that connects to a muscle
Onset more sudden than disuse
ALS, Lou Gehrig's disease, Guillon Barre
Pseudo-Hypertrophy - Increase in adipose tissue and connective tissue creates the appearance of
hypertrophy while no muscle hypertrophy has taken place
Basic Pathological Changes of Myopathy - Atrophy
Hypertrophy (Pseudo-Hypertrophy)
Degeneration
Limited Regeneration
Clinical Features of Myopathy - Weakness (hypotonia)
Fatigue
Wasting of tissues
Pain - asynergic pathological muscle pulling against joints
, Assessment of Myopathy - Clinical Exam (Muscle testing, DTR's)
Electromyography (EMG)
Serum Enzyme Assays
Muscle Biopsies
Assessment results of a Myopathic disease (Dystrophies) - No activity in the muscle at rest, no
change in the firing of the muscle
Fewer muscle fibers --> fewer muscle potentials that are shorter and smaller
Amplitude and duration decrease
Assessment results of a Neurogenic muscular disease - Fibrillations present
Decreased motor units
Amplitude and duration increase
What is considered the "go-to" lab test for assessing the presence of a dystrophy disease? -
Serum Enzyme Assays
EMG Assessment of Myopathy - Monitors spontaneous fibrillations
Motor unit potentials are of shorter duration and smaller amplitude in myopathic disease
Serum Enzyme Assays of Myopathy - "Go-to" lab test
Creatine kinase increase in Duchenne's muscular dystrophy
As muscle breaks down, it releases enzymes into blood
Other enzymes present: LDH, GOT, PK
Muscle Biopsies of Myopathy - Demonstrates Necrosis and regeneration
increase in Connective tissue, vascular tissue, nervous tissue
can help distinguish between different pathologies
Where are the nuclei in normal, healthy muscle? - Outside the contractile unit
Polygonal - many varied sides
characteristic of healthy muscle cell
What is found inbetween healthy muscle cells? - Blood vessels, connective tissue, fascial planes
Muscle Atrophy - Generalized muscle wasting
Muscle fiber death secondary to predisposing causes: Generalized primary disorders or localized
2025/2026 QUESTIONS WITH ANSWERS GRADED
A+
Atrophy - decrease in size or wasting away of tissue
Example of Inflammatory-Autoimmune Disorders - Myositis
Contenital Myopathy - Any myopathy present at birth
Leads to weakness in skeletal muscle
6 in 100,000 live births
Metabolic myopathy - Genetic defects with release of ATP and energy generating relating to
muscle
Myopathy - Disease of muscle tissue
2 types of atrophy - Disuse
Neurogenic
Disuse atrophy - lack of exercise
can be reversed
Neurogenic atrophy - Injury to a nerve that connects to a muscle
Onset more sudden than disuse
ALS, Lou Gehrig's disease, Guillon Barre
Pseudo-Hypertrophy - Increase in adipose tissue and connective tissue creates the appearance of
hypertrophy while no muscle hypertrophy has taken place
Basic Pathological Changes of Myopathy - Atrophy
Hypertrophy (Pseudo-Hypertrophy)
Degeneration
Limited Regeneration
Clinical Features of Myopathy - Weakness (hypotonia)
Fatigue
Wasting of tissues
Pain - asynergic pathological muscle pulling against joints
, Assessment of Myopathy - Clinical Exam (Muscle testing, DTR's)
Electromyography (EMG)
Serum Enzyme Assays
Muscle Biopsies
Assessment results of a Myopathic disease (Dystrophies) - No activity in the muscle at rest, no
change in the firing of the muscle
Fewer muscle fibers --> fewer muscle potentials that are shorter and smaller
Amplitude and duration decrease
Assessment results of a Neurogenic muscular disease - Fibrillations present
Decreased motor units
Amplitude and duration increase
What is considered the "go-to" lab test for assessing the presence of a dystrophy disease? -
Serum Enzyme Assays
EMG Assessment of Myopathy - Monitors spontaneous fibrillations
Motor unit potentials are of shorter duration and smaller amplitude in myopathic disease
Serum Enzyme Assays of Myopathy - "Go-to" lab test
Creatine kinase increase in Duchenne's muscular dystrophy
As muscle breaks down, it releases enzymes into blood
Other enzymes present: LDH, GOT, PK
Muscle Biopsies of Myopathy - Demonstrates Necrosis and regeneration
increase in Connective tissue, vascular tissue, nervous tissue
can help distinguish between different pathologies
Where are the nuclei in normal, healthy muscle? - Outside the contractile unit
Polygonal - many varied sides
characteristic of healthy muscle cell
What is found inbetween healthy muscle cells? - Blood vessels, connective tissue, fascial planes
Muscle Atrophy - Generalized muscle wasting
Muscle fiber death secondary to predisposing causes: Generalized primary disorders or localized
