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Chapter 42
Alterations of Musculoskeletal
Function
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Overview

Musculoskeletal injuries


Alterations in bones, joints, and muscles


Fractures, dislocations, sprains, and strains
Cause: metabolic disorders, infections,
inflammatory/noninflammatory diseases, or tumors
Trauma: leading cause of death of people
ages 1 to 44 years of all races and
socioeconomic levels
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2
Musculoskeletal Injuries

Fracture


A break in the continuity of a bone
Occurs when force is applied that exceeds the
tensile or compressive strength of the bone
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Musculoskeletal Injuries

Fracture classifications

Complete or incomplete
• Closed or open
 Comminuted
 Linear
 Oblique
 Spiral
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Fracture Classifications
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

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Transverse
Greenstick
Torus
Bowing
Pathologic
Stress
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
Fatigue and insufficiency
Transchondral
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Fractures
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Bone Fractures

Broken bone can damage the surrounding
tissue, the periosteum, and the blood vessels
in the cortex and marrow



Hematoma formation
Bone tissue destruction triggers an
inflammatory response
Procallus formation
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Callus Formation
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Bone Fractures
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Manifestations
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
Treatment
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Unnatural alignment, swelling, muscle spasm,
tenderness, pain, impaired sensation, and possible
muscle spasms
Closed manipulation, traction, open reduction
Improper reduction or immobilization

Nonunion, delayed union, and malunion
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Bone Fractures
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Improper reduction or immobilization
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Nonunion
• Failure of the bone ends to grow together
• Gap between the broken ends of the bone fills with
dense fibrous and fibrocartilaginous tissue
• Occasionally the fibrous tissue contains a fluid-filled
space that resembles a joint and is termed a false joint,
or pseudarthrosis
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Bone Fractures
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Improper reduction or immobilization
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
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Delayed union
• Does not occur until about 8 to 9 months after a fracture
Malunion
• Healing of a bone in a nonanatomic position
Treatment of delayed union and nonunion includes
modalities designed to stimulate new bone formation



Implantable or external electric current devices,
electromagnetic field generations, and low-density ultrasound
Gene therapy
Large defects in bone can be filled with bone graft or synthetic
materials, such as calcium phosphate cement
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Treatment
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Treatment
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Bone Fractures
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Dislocation
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Subluxation
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Temporary displacement of two bones
Loss of contact between articular cartilage
Contact between articular surfaces is only partially
lost
Dislocation and subluxation associated with
fractures, muscle imbalance, rheumatoid
arthritis, other joint instability
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Support Structure Injuries
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Strain
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Sprain
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Tear or injury to a tendon
Tear or injury to a ligament
Avulsion

Complete separation of a tendon or ligament from
its bony attachment site
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Tendinopathy and Bursitis
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Tendinitis
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Tendinosis
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
Inflammation of a tendon
Painful degradation of collagen fibers
Bursitis

Inflammation of a bursa
• Skin over bone, skin over muscle, and muscle and tendon over
bone


Caused by repeated trauma
Septic bursitis is caused by a wound infection
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Tendinopathy and Bursitis
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Epicondylitis

Inflammation of a tendon where it attaches to a
bone
• Tennis elbow (lateral epicondylitis)
• Golfer’s elbow (medial epicondylitis)
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Tendinitis and Epicondylitis
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Tendinitis and Epicondylitis
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Muscle Strain
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
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Sudden, forced motion causing the muscle to
become stretched beyond its normal capacity
Local muscle damage
Muscle strains can also involve the tendons
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Myositis Ossificans


Complication of local muscle injury
Inflammation of muscular tissue with
subsequent calcification and ossification of
the muscle
“Rider’s bone” in equestrians
 “Drill bone” in infantry soldiers
 Thigh muscles in football players

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Rhabdomyolysis
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Rhabdomyolysis (myoglobinuria) is a lifethreatening complication of severe muscle
trauma with muscle cell loss


Crush syndrome
Compartment syndromes
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Osteoporosis
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Porous bone
Poorly mineralized bone
Bone density
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
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Normal bone
• 833 mg/cm2
Osteopenic bone
• 833 to 648 mg/cm2
Osteoporosis
• <648 mg/cm2
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Osteoporosis
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Potential causes
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Decreased levels of estrogen and testosterone
Decreased activity level
Inadequate levels of vitamins D and C, or Mg++
Reduced bone mass/density and an
imbalance of bone resorption and formation
Bone histology is usually normal but it lacks
structural integrity
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Osteoporosis
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Osteoporosis
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Osteoporosis
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Perimenopausal osteoporosis
Iatrogenic osteoporosis
Regional osteoporosis
Postmenopausal osteoporosis
Glucocorticoid-induced osteoporosis
Age-related bone loss
Manifestations

Pain, bone deformity, fractures, kyphosis
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Osteoporosis
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Postmenopausal osteoporosis
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Occurs in middle-aged and older women
Serum androgens influence bone density
Androgens (i.e., testosterone and
dihydrotestosterone) stimulate bone formation
• Testosterone converted to estradiol by the enzyme
aromatase is associated with declining levels of estrogen
• Progesterone deficiency may also be related to osteoporosis
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Osteoporosis
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Postmenopausal osteoporosis
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Probably caused by changes in osteoprotegerin,
insulin-like growth factor (IGF), a combination of
inadequate dietary calcium intake and lack of vitamin
D, decreased magnesium, lack of exercise,
decreased levels of estrogen, and family history
IGF levels significantly decline by age 60. Excessive
phosphorus intake, chiefly through sodas and junk
foods, interferes with the calcium/phosphorus
balance; results in increased risk of brittle bones
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Osteomalacia
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

Deficiency of vitamin D lowers the absorption
of calcium from the intestines
Inadequate or delayed mineralization
Bone formation progresses to osteoid
formation but calcification does not occur; the
result is soft bones

Pain, bone fractures, vertebral collapse, bone
malformation
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Paget Disease
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
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Also called osteitis deformans
Excessive resorption of spongy bone and
accelerated formation of softened bone
Disorganized, thickened, but soft bones
Most often affects the axial skeleton
Thickened bones can cause abnormal bone
curvatures, brain compression, impaired
motor function, deafness, atrophy of the optic
nerve
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Osteomyelitis
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

Usually caused by a staphylococcal infection
Often from open wound (exogenous); also can
be from a blood-borne (endogenous) infection
Manifestations


Acute and chronic inflammation, fever, pain, necrotic
bone
Treatment

Antibiotics, débridement, surgery, hyperbaric oxygen
therapy
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Osteomyelitis
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Bone Tumors
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May originate from bone cells, cartilage,
fibrous tissue, marrow, or vascular tissue
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
Osteogenic, chondrogenic, collagenic, and
myelogenic
Malignant bone tumors

Increased nuclear/cytoplasmic ratio, irregular
borders, excess chromatin, a prominent nucleolus,
and an increase in the mitotic rate
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Bone Tumors
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Bone Tumors
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Patterns of bone destruction
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Geographic pattern
Moth-eaten pattern
Permeative pattern
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Bone Tumors
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Osteosarcoma
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
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38% of bone tumors
Predominant in adolescents and young adults;
occurs in seniors if a history of radiation therapy
Contain masses of osteoid
• “Streamers”: noncalcified bone matrix and callus
Located in the metaphyses of long bones
• 50% occur around the knees
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Osteosarcoma
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Bone Tumors
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Chondrosarcoma
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
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Tumor of middle-aged and older adults
Infiltrates trabeculae in spongy bone; frequent in
the metaphyses or diaphysis of long bones
The tumor contains lobules of hyaline cartilage
that expand and enlarge the bone
Causes erosion of the cortex and can expand into
the neighboring soft tissues
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Chondrosarcoma
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Bone Tumors
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Fibrosarcoma
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

Firm, fibrous mass of collagen, malignant
fibroblasts, and osteoclast-like cells
Usually affects metaphyses of the femur or tibia
Metastasis to the lungs is common
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Bone Tumors

Myelogenic tumors

Giant cell tumor
• Causes extensive bone resorption due to the osteoclastic
origin of the giant cells
• Located in the epiphyses of the femur, tibia, radius, or
humerus
• The tumor has a slow, relentless growth rate

Myeloma
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Giant Cell Tumor
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Inflammatory vs. Noninflammatory
Joint Disease
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Differentiated by:
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Absence of synovial membrane inflammation
Lack of systemic signs and symptoms
Normal synovial fluid analysis
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Osteoarthritis




Degeneration and loss of articular cartilage,
sclerosis of bone underneath cartilage, and
formation of bone spurs (osteophytes)
Also called degenerative joint disease
Incidence increases with age
Primary disease is idiopathic
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Osteoarthritis


Local areas of damage and loss of articular
cartilage, new bone formation of joint
margins, subchondral bone changes, and
variable degrees of mild synovitis and
thickening of the joint capsule
Manifestations

Pain, stiffness, enlargement of the joint,
tenderness, limited motion, and deformity
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Osteoarthritis
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Osteoarthritis
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Inflammatory Joint Disease


Commonly called arthritis
Inflammatory damage or destruction in
synovial membrane or articular cartilage and
by systemic signs of inflammation


Fever, leukocytosis, malaise, anorexia, and
hyperfibrinogenemia
Infectious or noninfectious
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Rheumatoid Arthritis (RA)
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Inflammatory joint disease
Systemic autoimmune damage to connective
tissue, primarily in joints (synovial membrane)
Similar symptoms to osteoarthritis
Presence of rheumatoid factors (RA or RF
test)


Antibodies (IgG and IgM) against antibodies
Joint fluid presents with inflammatory exudate
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Rheumatoid Arthritis (RA)
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Pathogenesis

CD4 T helper cells and other cells in the synovial
fluid become activated and release cytokines
 Recruitment and retention of inflammatory cells in
the joint sublining region
 Cycle of altered cytokine and signal transduction
pathways
 Possible immune complex deposition and
inflammatory cytokine release
 RANKL release and osteoclast activation
 Angiogenesis in the synovium
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Rheumatoid Arthritis (RA)
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Evaluation (4 or more of the following)

Morning joint stiffness lasting at least 1 hour
 Arthritis of three or more joint areas
 Arthritis of the hand joints
 Symmetric arthritis
 Rheumatoid nodules
 Abnormal amounts of serum rheumatoid factor
 Radiographic changes
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Rheumatoid Arthritis (RA)
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Rheumatoid Arthritis (RA)
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Ankylosing Spondylitis (AS)



Inflammatory joint disease of the spine or
sacroiliac joints causing stiffening and fusion
of the joints
Systemic, immune inflammatory disease
Primary proposed site is the enthesis


Site where ligaments, tendons, and the joint
capsule are inserted into bone
Cause unknown, but strong association with
HLA-B27 antigen
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Ankylosing Spondylitis (AS)




Begins with the inflammation of fibrocartilage,
particularly in the vertebrae and sacroiliac joint
Inflammatory cells infiltrate, erode fibrocartilage
As repair begins, scar tissue ossifies and
calcifies; joint eventually fuses
Early symptoms


Low back pain, stiffness, pain, and restricted motion
Loss of normal lumbar curvature
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Ankylosing Spondylitis (AS)
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Gout





Metabolic disorder that disrupts the body’s
control of uric acid production or excretion
Manifests high levels of uric acid in the blood
and other body fluids
Occurs when the uric acid concentration
increases to high enough levels to crystallize
Crystals deposit in connective tissues
throughout the body
When these crystals occur in the synovial
fluid, the inflammation is known as “gouty
arthritis”
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Gout



Related to purine (adenine and guanine)
metabolism
Affected people can have accelerated purine
synthesis, breakdown, or poor uric acid
secretion in the kidneys
Mechanisms for crystal deposition

Lower body temperatures, decreased albumin or
glycosaminoglycan levels, changes in ion
concentration and pH, and trauma
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Gout

Clinical stages



Asymptomatic hyperuricemia
Acute gouty arthritis
Tophaceous gout
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Gout
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Gout
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Disorders of Skeletal Muscle

Contracture



Muscle fiber shortening without an action potential
Cause: failure of the sarcoplasmic reticulum
(calcium pump) even with available ATP
Stress-induced muscle tension

Neck stiffness, back pain, clenching teeth, hand
grip, and headache
 Associated with chronic anxiety
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Fibromyalgia


Chronic widespread joint and muscle pain
Vague symptoms


Possible factors


Increased sensitivity to touch, absence of
inflammation, fatigue, sleep disturbances
Flu-like viral illness, chronic fatigue syndrome, HIV
infection, Lyme disease, medications, physical or
emotional trauma
Scientific studies are unclear
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Fibromyalgia
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Disuse Atrophy

Reduction in the normal size of muscle cells
due to prolonged inactivity


Bed rest, trauma, casting, or nerve damage
Treatment

Isometric movements and passive lengthening
exercises
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Muscle Membrane Abnormalities


Myotonia
Periodic paralysis


Hypokalemic periodic paralysis
Hyperkalemic periodic paralysis
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Diseases of Energy Metabolism

McArdle disease


Acid maltase deficiency



Myophosphorylase deficiency
Pompe disease
Myoadenylate deaminase deficiency (MDD)
Lipid deficiencies
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Polymyositis and
Dermatomyositis


Collectively described as myositis
Viral, bacterial, and parasitic myositis



Staphylococcus aureus infections
Trichinosis
• Trichinella infection
Toxoplasmosis
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Polymyositis and Dermatomyositis
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Toxic Myopathies

Most common cause is alcohol abuse



Acute attack of muscle weakness, pain, and
swelling
Chronic weakness in a drinker of long duration
Necrosis of individual muscle fibers
• Disturbance of energy turnover, gene dysregulation, and
initiation of apoptosis
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Muscle Tumors

Rhabdomyosarcoma




Malignant tumor of striated muscle
Usually muscles of the tongue, neck, larynx, nasal
cavity, axilla, vulva, and heart
Highly malignant with rapid metastasis
Types
• Pleomorphic, embryonal, and alveolar
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