septic arthritis; Infection of a joint space by bacteria, fungi, or viruses

Описание: Septic arthritis is a serious joint infection, most often caused by Staphylococcus aureus, that leads to rapid joint pain, swelling, and fever. It requires urgent treatment with antibiotics and drainage to prevent permanent joint damage or life‑threatening sepsis.

🧪 What Septic Arthritis Is
Definition: Infection of a joint space by bacteria, fungi, or viruses, leading to inflammation of synovial fluid and cartilage.

Commonly affected joints: Knees (most frequent in adults), hips (common in children), shoulders, ankles, sacroiliac joints.

Pathogenesis: Germs reach the joint via bloodstream (hematogenous spread), direct inoculation (injury, injection, surgery), or extension from nearby infection.

⚠️ Causes
Bacteria:

Staphylococcus aureus (including MRSA) → most common cause in adults and children.

Streptococcus species.

Neisseria gonorrhoeae → gonococcal arthritis, often affecting multiple joints.

Other organisms: Mycobacterium tuberculosis (chronic cases), fungi (Candida), viruses (rare).

🔎 Symptoms
Acute onset of severe joint pain.

Swelling, warmth, redness over the joint.

Fever and malaise.

Restricted range of motion; patient avoids using the joint.

In infants: irritability, pseudoparalysis (limb not moved).

🩺 Diagnosis
Joint aspiration (synovial fluid analysis): Gold standard. Gram stain, culture, WBC count.

Blood cultures: To identify systemic infection.

Imaging:

X‑ray: may show joint space widening or soft tissue swelling.

Ultrasound: detects effusion, guides aspiration.

MRI: early detection of joint involvement.

💊 Treatment
Immediate antibiotics: IV broad‑spectrum, tailored after culture results.

Joint drainage: Needle aspiration, arthroscopic lavage, or open surgery.

Physical therapy: After infection control, to restore mobility.

Prosthetic joint infection: Often requires removal of the prosthesis and staged replacement.

#Sepsis #Arthritis