Ch. 39 - Joint zTypes & Blood Supply to Bones, Joints, and Cartilage

Pathophysiology Exam 3

What is a joint (articulation)?

The point where two or more bones meet, allowing varying degrees of movement

What are the three structural types of joints?

Fibrous

Cartilaginous

Synovial

Which type of joint is immovable?

Fibrous joints

Example: Skull sutures

Which type of joint allows alight movement?

Cartilaginous joints

Example: Intervertebral discs and the pubic symphysis

Which type of joint is freely moveable?

Synovial joints

What are the major components of a synovial joint?

Articular cartilage

Synovial membrane

Synovial fluid

Joint capsule

Ligaments

What is the function of of articular cartilage?

Toreduce friction and absorb shock during joint movement

What is the function of the synovial membrane?

It produces synovial fluid

What is the function of synovial fluid?

It lubiractes and nourishes the articular cartilage

What is the function of ligaments?

They connect bone to bone and help stabilize joints

What type of synovial joint is the shoulder?

Ball-and-socket joints

What type of synovial joint is the hip?

Ball-and-socket

What type of synovial joint is the knee?

Hinge joint

What type of synovial joint is the elbow?

Hinge joint

What type of synovial joint allows rotation of the head?

Pivot joint

Which joint allows the greatest range of motion?

The shoulder (ball-and-socket joint)

Why do bones have a rich blood supply?

To deliver oxygen and nutrients, remove waste, and support bone growth and healing

Why is blood supply important after a fracture?

Bone healing depends on an adequate blood supply

Which part of the bone contains many blood vessels?

The periosteum

What may happen if the blood supply to bone is disrupted?

Delayed healing or bone death (avascular necrosis)

Does articular cartilage have its own blood vessels?

No

How does articular cartilage receive nutrients?

By diffusion from synovial fluid

Why does cartilage heal slowly?

It has no direct blood supply

Which structure nourishes the cartilage inside a joint?

Synovial fluid

Why is regular movement beneficial for joint health?

Movement helps circulate synovial fluid, improving nutrient delivery to cartilage

Which joint type of most commonly affected by arthritis?

Synovial joints

Which tissue heals more slowly: bone or cartilage?

Cartilage, because it lacks a direct blood supply

Which structure produces synovial fluid?

The synovial membrane

Which structure cushions the ends of bones?

Articular cartilage

What is the most movable type of joint?

Synovial joints

What is osteomyelitis?

An infection of the bone that causes inflammation, bone destruction, and, if untreated, can lead to necrosis

What is the most common cause of osteomyelitis?

Bacterial infection, most commonly Staphylococcus aureus

What does “osteo” mean?

Bone

What does “myelitis” refer to in osteomyelitis?

Inflammation involving the bone and bone marrow

How can bacteria reach the bone?

Through the bloodstream (hematogenous spread)

From an open fracture or penetrating injury

During surgery

By spread from a nearby infected tissue or ulcer

Which patients are at highest risk for osteomyelitis?

Patients with diabetes

People with open fractures

patients with pressure injuries or chronic foot ulcers

Individuals with weakened immune systems

People who have recently had orthopedic surgery

Why are patients with diabetes at risk?

Poor circulation and decreased wound healing increase the likelihood of infection spreading to bone

Why do open fractures increase the risk?

The broken bone is exposed to bacteria from the external environment

What happens when bacteria invade bone?

The infection triggers inflammation, swelling, and destruction of bone tissueW

Why can osteomyelitis reduce blood flow within bone?

Swelling and inflammation increase pressure, which can compress blood vessels

What is sequestrum?

A piece of dead bone that has separated from healthy bone due to infection

Why is sequestrum a problem?

Antibiotics have difficulty reaching dead bone, making the infection harder to eradicate

What are the common symptoms of osteomyelitis?

Localized bone pain

Swelling

Redness

Warmth

Fever

Decreased movement of the affected area

What symptom is usually the earliest complaint?

Localized bone pain

What signs may suggest chronic osteomyelitis?

Persistent drainage from a sinus tract

Chronic pain

Recurrent infections

Which laboratory tests are commonly elevated in osteomyelitis?

White blood cell (WBC) count

C-reactive protein (CRP)

Erythrocyte sedimentation rate (ESR)

Which imaging study is most useful for detecting osteomyelitis early?

MRI

What is the definitive test for diagnosing osteomyelitis?

Bone biopsy with culture

Why is a bone culture important?

It identifies the specific organism so antibodies can be targeted appropriately

Which is the primary treatment for osteomyelitis?

Prolonged antibiotic therapy, often given intravenously at first

Why are antibiotics often given for several weeks?

Bone infections are difficult to treat because antibiotics penetrate bone tissue more slowly than many other tissues

When is surgery indicated?

Dead bone (sequestrum) is present

An abscess has formed

The infection does not respond adequately to antibiotics

What is debridement?

Surgical removal of infected or dead tissue to promote healing

What is the nurse’s priority when caring for a patient with osteomyelitis?

Administer prescribed antibiotics, monitor for signs of worsening infection, and assess pain

What should the nurse monitor during treatment?

Temperature

WBC count

CRP/ESR trends

Wound appearance (if present)

Pain level

Why is completing the full course of antibiotics important?

To reduce the risk of persistent or recurrent infection

What is the hallmark symptom of osteomyelitis?

Localized bone pain with signs of infection

Which organism causes most cases of osteomyelitis?

Staphylococcus aureus

Which imaging study is most useful early in the disease?

MRI

What is the definitive diagnostic test?

Bone biopsy with culture

What is the primary treatment?

Long-term antibiotics, with surgery if necessary

What is gout?

A type of inflammatory arthritis caused by the deposition of monosodium urate (uric acid) crystals in the joints due to elevated uris acid levels (hyperuricemia)

What causes gout?

Hyperuricemia (high uric acid levels) leading to uric acid crystal formation in joints

What is uric acid?

A waste product formed from the breakdown of purines, which are found naturally in the body and in certain foods

What are purines?

Natural substances found in the body tissues and foods such as red meat, organ meats, seafood, and some alcoholic beverages

What are common risk factors for gout?

Male sex

Older age

Obesity

High-purine diet

Alcohol use (especially beer)

Kidney disease

Family history

Certain medications (such as some diuretics)

Why does kidney disease increase the risk of gout?

The kidneys are less able to eliminate uric acid, causing it to accumulate in the blood

Why can some diuretics increase gout risk?

They can reduce uric acid excretion by the kidneys

What happens when uric acid levels become too high?

Needle-shaped crate crystals form and deposit in joints, triggering intense inflammation

Why are gout attacks so painful?

The immune system reacts strongly to irate crystals, causing acute inflammation

What is the classic presentation of an acute gout attack?

Sudden onset of severe joint pain, redness, warmth, swelling, and tenderness, often occurring at night

Which joint is most commonly affected first?

The first metatarsophalangeal (MTP) joint of the big toe (podagra)

Besides the big toe, which other joints may be affected?

Ankles

Knees

Wrists

Elbows

Fingers

What are tophi?

Firm deposits of uric acid crystals that develop in soft tissues with long-standing or poorly controlled gout

Where are tophi commonly found?

Fingers

Toes

Elbows

Ears

How is gout diagnosed?

History and physical examination

Joint aspiration with crystal analysis (definitive test)

Serum uric acid level (may support the diagnosis but can be normal during acute attack)

What is the gold standard for diagnosing gout?

Joint aspiration showing monosodium urate crystals

Can a normal serum uric acid level rule out an acute gout attack?

No, uric acid levels may be normal during an acute flare

What is the goal during an acute gout attack?

Relieve pain and reduce inflammation

Which medications are commonly used for acute gout attacks?

NSAIDs

Colchicine

Corticosteroids (when indicated)

Which medication is commonly used for long-term uric acid lowering?

Allopurinol

Should allopurinol be started during an acute gout attack unless specifically directed by the provider?

No, it is generally not initiated during an acute flare because changes in uric acid levels may prolong or worsen symptoms

If a patient is already taking allopurinol before the flare, it is usually continued while the flare is treated

How does allopurinol work?

It reduces uric acid production

What dietary changes help prevent gout attacks?

Limit red meat and organ meats

Reduce certain seafood high in purines

Limit alcohol (especially beer)

Stay well hydrated

Maintain a healthy weight

Why is hydration important?

It helps the kidneys eliminate uric acid

What is the nurse’s priority during an acute gout attack?

Control pain

Reduce inflammation

Protect the affected joint

Should patients rest the affected joint during an acute attack?

Yes, rest can help reduce pain and inflammation

What is the hallmark symptom of gout?

Sudden, severe pain in the big toe with redness, warmth, and swelling

What is the gold standard diagnostic test?

Joint aspiration with identification of monosodium urate crystals

Which medication treats an acute attack?

Colchicine (along with NSAIDS or corticosteroids when appropriate)

Which medication helps prevent future attacks by lowering uric acid?

Allopurinol

Which joint should immediately make you think of gout on an exam?

The first metatarsophalangeal (big toe) joint