MOD 10 - Inflammatory and Metabolic Disorders

Types of Inflammatory Disorders

• osteomyelitis

• osteoarthritis

• rheumatoid arthritis

• gout

• ankylosing spondylitis

Common causes of inflammation

• infectious pathogens

• allergens

• cuts, scrapes, and fractures

• immune reactions from antibody production

Common Inflammatory Symptoms

• tissue swelling: increased plasma → increased pressure contributes to pain

• joint swelling: direct result of the accumulation of fluid; also attributes to pain and decreased ROM

• pus formation: causes an increase in necrotic tissue as pus composition is mainly dead/necrotic/destroyed cells

• ulceration/scarring: a result of the tissue repair

Osteomyelitis (DERTC)

• common in metaphyseal area, lower ext, children <5yr

• MOI = a secondary infection caused by staphylococcal bacteria

• internal bone is usually thickened with irregular patches of sclerosis (honeycomb effect of the internal bone)

• good prognosis detected early and treated with antibiotics

• bone necrosis, septic arthritis

Osteomyelitis - Pathogenesis

1. Formation of a sequestrum fragmented necrotic bone due to abscess

2. Formation of involucrum (new bone)

3. Reabsorption of sequestrum and formation of new irregular bone around the abscess

4. Migration of the staphylococcal bacteria via bloodstream

Brodie’s abscess

• a chronic bone abscess in the metaphyseal area of the bone

• common in children

Osteoarthritis (DERTC)

• types of OA

  • primary: degenerative condition involving the cartilage of weight-bearing bones

  • secondary: orthopedic deformities or malunion

• MOI + associated with continual stress to the joints; normal aging process (appears >40yrs)

• narrowing of the joint spaces, osteophytes

• pain killers, lifestyle changes, surgery

OA - Pathogenesis

• eburnation

• cause of osteophytes

• bone becoming hard and glossy due to cartilage wear down

• result of inflammation and irritation of the periosteum

Heberden’s nodes

a result of osteophyte formation of the bones, which give the hands a bumpy external appearance

Rheumatoid Arthritis (DERTC)

• occurs initially between 30-58 years old; seen most commonly in women 25-45 years old

• an autoimmune systemic disease which affects both joints and soft tissue; non-bacterial inflammatory disease

• Rarefaction = the distinct appearance of the dense cortex vs. less dense medullary cavity

• no cure, but can alleviate symptoms: joint reconstruction, total joint arthroplasty, osteotomy, tendon repair, etc

RA - Pathogenesis

synovial membrane is thickened due to the inflammation process → the exudate results in pannus production (granulation of connective tissue) → which fills the joint space and erodes the articular cartilage → the bony ends erode and eventually fuse to adjacent bone structures = ankylosis

Gout (DERTC)

• common in males (30-50yrs) and females post-menopausal; most common for males on diuretics (for CHF)

• an inherited metabolic disorder that affects the joint and adjacent bone; polyarthritis

• gout arthritis: lytic lesions, over-hanging edges of sclerosis

• treatment is to reduce the production of uric acid or promote kidney excretion

• uric acid kidney stones due to increased uric acid excretion by the kidneys

Gout - Pathogenesis

• excess uric acid production causes a mass-like deposit in the joints, which then crystallize (tophi) and lead to an acute inflammatory process

• symptoms are localized pain, erythema, swelling, and heat due to acute inflammation

Ankylosing Spondylitis (DERTC)

• primarily affects the vertebral column; affects more male; begins in the SIJ

• progressive inflammatory condition and is polyarthritic

• blurred bony margins and narrowing/fusion of SIJ (bamboo like appearance)

• no cure; given anti-inflammatory drugs and encouraged to exercise

Ankylosing Spondylitis - Pathogenesis

• inflammation causes the SIJ to widen → new bone formation and eventual fusion of the SIJ → progresses sup. invading the vertebral column

• bones become very brittle and pts are prone to osteoporosis

Osteoporosis and Osteopenia (DERTC)

• osteoporosis = overall bony demineralization due to calcium reduction in the bones; metabolic disease

  • generalized = bone density is decreased overall; common in post-menopausal women

  • regional = confined to a specific area of the body due to immobilization (seen within 7-10 days of inactivity)

  • localized = affects only a small area of the bone due to local disease

• osteopenia = the loss of bone density, more common in people >50yrs

• MOI = unknown, but five known factors are: hormones, calcium intake, levels of activity, diet, age

• rad appearance: bony cortex appears starkly white against the hazy grey trabecula "picture frame pattern"

• treatment: supplementation of vitamin D, calcium, and magnesium, and patients are prescribed weight-bearing exercises

Osteoporosis - Pathogenesis

osteopenia has no signs or symptoms

• loss of height (kyphosis in the thoracic spine) due to the anterior portion of the vertebra collapsing

• back pain

• localized or general bone pain

• Spontaneous fractures may occur with minimal trauma. FOOSH injuries are commonplace

DEXA Usage

used as screening tools to assess bone quality for osteoporosis

• T-score less than -1 = normal

• T-score between -1 and -2.5 = osteopenia

• T-score less than -2.5 = osteoporosis