Untreated, bacteria destroy cartilage in 48 hours. Can lead to sepsis, amputation, or death.

Action:

→ ER within 6 hours.

→ Requires IV antibiotics + joint fluid drainage.

📉 Fact: 25% of septic arthritis cases start with “mild swelling.” Delay = 3x higher risk of permanent joint damage.

2. Gout or Pseudogout — Sudden & Brutal

🛑 See a doctor within 24 hours.

Gout

Uric acid crystals (from red meat, alcohol, fructose)

Men over 40, postmenopausal women

Pseudogout

Calcium pyrophosphate crystals

Older adults, thyroid issues

Red Flags:

⚡ Wakes you at 3 a.m. with excruciating pain

🌶️ Skin bright red or purple

📈 Swelling peaks in 12–24 hours

🍷 Often after a rich meal or drinking binge

Why it’s tricky:

Looks like infection — but antibiotics won’t help. Needs anti-inflammatories or crystal-dissolving meds.

Action:

→ See a doctor ASAP.

→ Joint fluid test confirms diagnosis.

→ Treated with NSAIDs, colchicine, or steroids.

3. Trauma or Internal Injury (Meniscus Tear, ACL Sprain)

🛑 See a doctor within 48 hours.

Cause: Twisting, pivoting, or impact — even minor

Signs:

💥 “Pop” at time of injury

🧩 Swelling within 2–6 hours (blood in joint)

🚶‍♂️ Instability — knee “gives out”

🔁 Locking or catching

Common in: Athletes, weekend warriors, older adults with weakened cartilage

Action: