Exam 2 patho

Mechanisms of abnormal skeletal muscle contractions

issues often related to ATP and electrolytes or problems with neurotransmitters.

Common problems with musculoskeletal disorders

1. weakness

2. fatigue

3. cramps

4. direct injury

Weakness (loss of strength) due to:

• disuse (atrophy) muscle cells shrink, loss of noncontractile protein

• Systemic wasting disorders. the muscle tissue is replaced by abnormal tissue. 

Fatigue 

the loss of power or force in the muscle 

• Intracellular acidosis (lactic acid) 

• Lack of energy production (disorders with rapid energy depletion) 

• Disruption in calcium flux

Cramps

involuntary muscle spasms due to dehydration or electrolyte depletion. The muscle remain in contractile state because of improper depolarization.

Direct injury are either:

Hematoma or muscle tears 

Hematoma

bleeding into muscle tissue

Muscle tears

• Myoglobin released in urine - filtered out by the kidneys

 Myoglobinuria (rhabdomyolysis) - myoglobin in the urine, rhabdomyolysis is a life-threatening complication of muscle trauma.

 Increased creatine phosphokinase (CPK) - damage to heat, muscle, brain

 Risk for renal failure - especially with rhabdomyolysis, myoglobin can damage the kidney cells and kidney’s can’t clear waste like they should.

Pathological Muscle Disorders

1. Muscular dystrophies 

2. Inflammatory myopathies

3. Cancer of muscle 

Muscular Dystrophies

genetically transmitted through recessive gene on the X chromosome, produces

progressive muscle wasting. deterioration of skeletal muscle

Muscular dystrophies classifications

Rapidly progressing: Duchenne’s muscular dystrophy (onset at 5 years of age, most common form seen)

b. Slower progressing: Becker’s, limb-girdle 

Pathophysiology of Muscular dystrophies

b. Defect in gene that produces dystrophin

c. Muscles cells die → phagocytosis (process to remove dead cells)

d. Replaced with fatty tissue (enters the muscle fibers and weakens the muscle)

e. Respiratory and cardiac failure (these muscles affected)

Dystrophin

protein thought to affect muscle contraction

CM of Muscular Dystrophies 

Difficulties with early motor development (they could have normal development at birth but can be delay in walking)

 Gower's maneuver - use the hands and arms to get up and walk because of the decrease in muscle strength in the hips and thighs. they walk up the body from sitting. 

b. Progression - falls and wheelchair use 

inflammatory Myopathies

1. Polymyositis 

2. dermatomyositis 

3. Fibromyalgia 

Polymyositis 

Inflammation of muscle groups

a. Autoimmune or viral - self-reactive B and T cells attack the muscle

b. Patchy muscle necrosis - neck, limbs, chronic inflammation results

c. May involve the joints - painful swelling

d. Progression of weakness - cardiac and respritory involvement

Dermatomyositis

• the autoimmune response following infection causing muscle weakness 

a. Rash and puffiness of the eyes and face 

b. Sluffing of skin, calcification - manifests nodules in bony areas

Fibromyalgia

a. Chronic musculoskeletal pain with no evidence of arthritis

b. Stiffness, fatigue - tender areas, elevated by stress

c. Inappropriate levels of neurotransmitters (being investigated)

• Decreased ATP and creatine phosphate levels in areas of tenderness - neck, hip, shoulders, low back

cancer of the muscle

Rhabdomyosarcoma - head, neck, abdomen, extremities. soft tissue mass

Disorders of the bones and joints

1. Fractures and associated injuries

2. bone disease

3. Alterations in joints 

Fractures and Associated injuries (5)

1. classifications of fractures 

2. dislocation 

3. signs and symptoms of fractures 

4. fracture healing 

5. soft tissue traumas

Classifications of fractures

• break in the continuity of a bone 

1. Simple

2. Compound

3. Complete

4. Comminuted

5. Depressed

6. Compression

simple and compund

simple - no break in the skin, no separation of bone

compound - through the skin, bone protrudes 

Comeplete 

through entire bone with separation, could be simple or compound 

Comminuted

three or more fragments of the bone

depressed

bone drawn inward

compression 

one of more bones in the spine weaken or crumble, could be due to osteoporosis or loss of bone mass 

Dislocation

involves the separation and displacement of the bone from the joint

Signs and symptoms of fractures

• inflammatory process initiated at the cite 

1. Swelling, bruising, soft tissue injury 

2. Loss of function - depends on the cite 

3. Deformity - ambulation 

4. Pain - at the cite, increase with touch or movement 

fracture healing

formation of new bone (osteoblasts - cells that help form the new bone cells) through sequential process - remodeling

1. immobilization problems 

2. blood supply 

3. infection (osteomyelitis)

Immobilization problems

movement occurs can compromise new development of bone

blood supply

need good blood supply, can’t if swelling is bad

Infection (osteomyelitis) - of the bone

a. Bloodstream or extension of infection - from another part of the body 

b. Direct surgical or traumatic introduction - if fracture is open or trauma occurs where organisms can enter 

 Organism adheres to bone → inflammatory response

 Exudate forms - collects along the bone 

c. Nonunion (infection, movement) - bone fails to fuse and heal

d. Compartment Syndrome:

compartment syndrome

• muscle and nerve damage due to excessive swelling. you need a fasciotomy to cut the facia and relieve the pressure

 Enclosed area: pressure builds within the compartment - in the facia compartment

 Fascia permits no outward enlargement - edema expands the enclosed area

 Compression of blood vessels and nerves leads to necrosis and gangrene if no

intervention. decrease in oxygen to the tissues

Soft tissue traumas

tendon/ligament damage

visceral damage 

sprains 

strains 

Tendon/ligament damage

a. Avulsion: pulling apart of piece of bone attached to tendon (separation usually)

b. Tendon laceration: Loss of ability to flex or extend - hands, knees, feet (Achilles tendon rupture)

c. Physical tear in ligament - torn ACL (most common)

d. Healing tendon or ligament - gradual process (several weeks)

Visceral damage

• with fractures, when bone punctures other areas 

• organs - lungs, liver, spleen are common) ribs can puncture

Sprains

Ligaments or joint capsule. Damage caused by an abnormal movement of the joint

Stains

stretching or partial tear in muscle or muscle-tendon unit. A sudden abnormal stretch of a contracting muscle. 

Bone diseases (5)

Osteoporosis

Osteomalacia 

Paget Diseases (osteitis deformans) 

Bone cancer 

Disorders of bone growth 

Osteoporosis

• decrease in bone density and strength due to a reduction in bone matrix and mineralization. Usually in weight bearing bones 

Reduction in bone matrix and mineralization

a. Numerous risk factors - age, smoking, loss of activity 

b. Osteopenia - early decrease in bone density not quite osteoporosis 

c. Bone loss exceeds bone formation leading to thinning of the cortex - minimal force/stress can develop a fracture (sometimes its not the fall but the bone broke first and then they fell. 

Classification

Type 1 - develops with early post metapodial estrogen deficiency

Type 2 - calcium deficiency 

CM of weakening bone

a. Fracture - (most common) hips, head of femur, distal radius 

b. Loss of height - with a decrease in the density of the vertebrae 

c. Kyphosis (dowager hump) - arch of upper back 

Osteonecrosis 

• Eventual death of bone cells can result in rough not smooth. 

Osteomalacia and etiology

Softening of bone (adult form of rickets)

Etiology:

1. calcium, vitamin D or phosphate deficiency - dietary intake or kidney disease 

2. Medications, lack of sunlight - can decrease activation of VD synthesis. 

Patho of Osteomalacia

a. Inadequate mineralization → weakening of bone 

Cm of Osteomalacia

Pain, fractures, bowing of legs

Paget Disease (osteitis deformans) and etiology

• next most common after osteoporosis of bone diseases 

Etiology: genetic and environmental influences; greater incidence in men - can be triggered by a viral infection 

Patho of Paget Disease

a. Excessive bone resorption - rapid destruction of bone

b. Disorganized bone repair with newly formed bone of poor quality - newly form bone is deposited chaotically

 Mosaic like pattern - grow outward

c. Adjacent bone marrow replaced by loose connective tissue and blood vessel

CM of Paget Disease

Skeletal expansion and distortion - skull, jaw, long bones of leg 

b. Headache, dizziness - if skull involved 

c. Kyphosis - due to vertebral weakening 

d. Bowing of leg bones

e. Increased risk for osteogenic sarcomas - occurs with extensive disease 

Bone cancer (5)

Benign

malignant 

pathophysiology 

Hypercalcemia possible 

Osteosarcoma 

Benign

common in children and teens

a. Fibrous origin: common in growing bones

b. Cartilaginous origin: chondromas or osteochondromas - cancer starts in cartilage and moves to bones 

Malignant: Primary or secondary

Primary: starts in the bones

Secondary: cancer originates elsewhere and metastasizes to the bone 

• usually seen in children and teens. 

a. Rapid growth - beyond bone tissue

b. Symptoms: pain, unexplained swelling, feeling of warmth

Patho of bone cancer

a. increased production of abnormal bone, cartilage, or surrounding tissue

b. Malignant = destructive to adjacent normal cells - metastasizes to the lungs commonly

c. Weakens bone - because of loss of bone tissue

Hypercalcemia possible

Hormones secreted by tumor increase reabsorption of Calcium or increased parathyroid related peptides - more calcium pulled into the blood 

Osteosarcoma

: circular ball-like mass in bone tissue - most common type of bone cancer

Disorders of bone growth (2)

Scoliosis

Osteogenesis Imperfects 

scoliosis

lateral - curvature of the spine

Osteogenesis Imperfecta

a (brittle bone disease): genetic mutation

a. Disorder of synthesis of collagen - collagen are a major component of bones 

b. Prone to fractures, osteoporosis, deformed limbs - they often need frequent operations

Alterations in joints (6)

1. Osteoarthritis (Degenerative joint disease: DJD)

2. Rheumatoid arthritis: Systemic autoimmune disease

3. Ankylosing Spondylitis

4. bursitis 

5. Osteochondrosis 

6. Gout: metabolic disorder

Osteoarthritis (Degenerative joint disease: DJD

progressive breakdown of cartilage (most prevalent joint disease)

Osteoarthritis (Degenerative joint disease: DJD) Patho

: depletion of matrix in articular cartilage - surface flakes off

Collagen fibers exposed - cartilage becomes thin and cracks develop

b. Synovial fluid enters the cracks: formation of cysts

c. Synovial capsule decreases in size → exposing bone (bone on bone)

CM of Osteoarthritis (Degenerative joint disease: DJD)

• due to enlargement of joints

a. Pain, stiffness - particularly in weight bearing joints 

b. Difficulty with movement - limp, limited range of motion 

Rheumatoid arthritis

Systemic autoimmune disease - starts with joints 

1. IgG/rheumatoid factor (RF) interaction (auto antibody) 

2. Activation of a T-cell mediated response to an immunologic trigger (infection)

3. Inflammation in joints → thickening and destruction of cartilage

4. Synovial membrane thickens → pannus development → scar tissue (abnormal tissue growth in joints space)

CM of Rheumatoid arthritis

Systemic: fever, weakness, weight loss, stiffness

b. Joint pain, tenderness (part. in AM) - pressure with swelling

c. Warmth, bogginess - mushy texture in joint 

d. Loss of mobility - progressive limitation 

e. Rheumatoid nodules in skin, heart, lungs, and spleen

Ankylosing Spondylitis

1. autoimmune 

2. Inflammation of skeletal joints (low back)

2. Stiffening and fusion of spine and sacroiliac joints - chronic inflammation leads to low back pain and stupped posture 

Bursitis

1. Inflammation of a bursa - painful swelling of the sack that cushions and lubricates the joints

• Excess fluid

• Pressure on sensory nerve endings

2. Trauma, infection, rheumatoid arthritis

3. Knee, elbow, feet (overuse)

Osteochondroses

• series of childhood disorders with a decrease of blood supplies to the

1. Joints Legg-Calve-Perthes Disease: affects femoral head - and blood supply to there, bone dies and stops growing 

2. Osgood-Schlatter Disease - tibular and patellar tendonitis and inflammation, usually seen with athletic. peer adolescent age 

Gout:

metabolic disorder - affects joints and causes pain

1. Increased levels of uric acid - causing inflammation 

2. Uric acid crystals may precipitate into joint - and connective tissue