Septic Bursitis: Causes, Symptoms, Diagnosis, and Treatment

What is Bursa Sac Sepsis?

Bursa sac sepsis, more commonly known as septic bursitis, is a serious bacterial infection of a bursa sac, characterized by inflammation, pain, and often systemic signs of infection, requiring prompt medical diagnosis and aggressive treatment to prevent severe complications.

Understanding Septic Bursitis

Septic bursitis is a distinct and more severe form of bursitis, which is the inflammation of a bursa sac. While bursitis can often be aseptic (non-infectious) due to overuse, trauma, or inflammatory conditions, septic bursitis specifically refers to an infection within the bursa, most commonly caused by bacteria. This condition demands urgent medical attention due to its potential to spread and cause systemic illness.

The Role of Bursa Sacs in Anatomy

Bursae (plural of bursa) are small, fluid-filled sacs lined with a synovial membrane, similar to the lining of a joint capsule. Their primary function is to reduce friction and cushion pressure points between bones, tendons, muscles, and skin around joints. They act as natural shock absorbers and facilitate smooth movement.

While bursae are found throughout the body, those most commonly affected by septic bursitis are superficial bursae located directly under the skin, making them more vulnerable to bacterial entry. These include:

• Olecranon bursa: Located at the tip of the elbow.
• Prepatellar bursa: Located over the kneecap.
• Infrapatellar bursa: Located below the kneecap.
• Trochanteric bursa: Located on the outer side of the hip.

Causes of Septic Bursitis

Septic bursitis typically occurs when bacteria gain entry into a bursa sac. The most common culprit is Staphylococcus aureus (staph), but Streptococcus species and other bacteria can also be responsible. The primary pathways for bacterial invasion include:

• Breaks in the Skin: The most frequent cause is a direct entry through a cut, scrape, abrasion, puncture wound (e.g., insect bite, thorn, injection), or surgical incision overlying the bursa.
• Skin Conditions: Chronic skin conditions like psoriasis, eczema, or open sores can compromise the skin barrier, allowing bacteria to enter.
• Spread from Nearby Infection: Less commonly, an infection in adjacent tissue (like cellulitis) can spread to the bursa.
• Hematogenous Spread: In rare cases, bacteria from a distant infection can travel through the bloodstream (bacteremia) and seed a bursa, especially if the bursa has been previously traumatized or inflamed.

Risk Factors

While anyone can develop septic bursitis, certain factors increase susceptibility:

• Compromised Immune System: Individuals with weakened immune systems are at higher risk. This includes people with diabetes, HIV/AIDS, cancer, chronic kidney disease, or those on immunosuppressive medications (e.g., corticosteroids, post-organ transplant).
• Skin Integrity Issues: Conditions that impair the skin barrier, such as psoriasis, eczema, or chronic skin ulcers, increase the risk of bacterial entry.
• Repetitive Trauma or Pressure: While not a direct cause of infection, repeated friction or direct pressure on a bursa (e.g., prolonged kneeling for prepatellar bursitis, leaning on elbows for olecranon bursitis) can lead to aseptic inflammation, potentially making the bursa more vulnerable to infection if a skin break occurs.
• Alcoholism: Chronic alcohol abuse can weaken the immune system.
• Previous Aseptic Bursitis: An already inflamed bursa may be more susceptible to infection if bacteria gain entry.

Signs and Symptoms

The symptoms of septic bursitis are generally more severe and often include systemic signs compared to aseptic bursitis. Key indicators include:

• Intense Localized Pain: Severe pain in the affected area, often throbbing, and significantly worse with movement or pressure.
• Warmth: The skin over the bursa feels noticeably hot to the touch.
• Redness (Erythema): Distinct and often spreading redness around the bursa.
• Swelling: Significant and often rapid accumulation of fluid within the bursa, causing visible swelling.
• Tenderness: Extreme pain upon even light touch or palpation of the bursa.
• Fever and Chills: Systemic signs of infection are common, indicating the body's generalized response to the bacterial invasion.
• Malaise: A general feeling of unwellness, fatigue, or lethargy.
• Swollen Lymph Nodes: Lymph nodes near the affected area may become enlarged and tender.

Diagnosis

Accurate and timely diagnosis of septic bursitis is crucial for effective treatment. The diagnostic process typically involves:

• Clinical Examination: A thorough physical examination to assess the affected bursa for characteristic signs of infection (redness, warmth, swelling, tenderness) and to evaluate for any skin breaks or systemic symptoms.
• Medical History: Gathering information about recent injuries, skin lesions, underlying health conditions, and risk factors.
• Bursa Fluid Aspiration (Arthrocentesis): This is the definitive diagnostic test. A sterile needle is used to draw fluid directly from the infected bursa. The fluid is then sent for laboratory analysis:
  • Cell Count: To determine the number and type of white blood cells (elevated neutrophils indicate infection).
  • Gram Stain: To quickly identify the presence and type of bacteria (Gram-positive or Gram-negative).
  • Culture and Sensitivity: To grow the specific bacteria responsible and determine which antibiotics will be most effective against it.
  • Glucose and Protein Levels: Can provide additional clues about infection.
• Blood Tests:
  • Complete Blood Count (CBC): May show an elevated white blood cell count (leukocytosis), indicating a systemic infection.
  • Inflammatory Markers: C-reactive protein (CRP) and Erythrocyte Sedimentation Rate (ESR) are often elevated, reflecting generalized inflammation.
• Imaging Studies: While not typically used to diagnose septic bursitis directly, imaging like X-rays, ultrasound, or MRI may be performed to rule out other conditions (e.g., fracture, foreign body, joint infection) or to assess the extent of the bursal inflammation.

Treatment Approaches

Treatment for septic bursitis is aggressive and typically involves a combination of medical interventions:

• Antibiotics: This is the cornerstone of treatment.
  • Empiric Antibiotics: Broad-spectrum antibiotics are usually started immediately after bursa fluid aspiration, before culture results are available, to cover the most common causative bacteria (e.g., Staphylococcus).
  • Targeted Antibiotics: Once culture and sensitivity results are back (typically within 24-48 hours), the antibiotic regimen is adjusted to specifically target the identified bacteria.
  • Administration: Antibiotics may be given intravenously (IV) for severe infections or orally for less severe cases. The course typically lasts 1 to 2 weeks, sometimes longer.
• Drainage:
  • Repeated Aspiration: The infected fluid may need to be repeatedly drained from the bursa to reduce pressure, remove bacteria, and allow antibiotics to work more effectively.
  • Incision and Drainage (I&D): If the infection is severe, persistent, or if the bursa is loculated (divided into compartments), a surgical incision and drainage procedure may be performed to thoroughly clean out the bursa.
• Pain Management: Over-the-counter or prescription pain relievers (e.g., NSAIDs, acetaminophen) are used to manage the severe pain associated with the infection.
• Rest and Immobilization: Resting the affected area and sometimes immobilizing the joint can help reduce irritation, pain, and promote healing.
• Surgical Bursectomy: In rare cases, if the infection is chronic, recurrent, or fails to respond to other treatments, surgical removal of the bursa (bursectomy) may be considered.

Prevention Strategies

Preventing septic bursitis primarily focuses on maintaining skin integrity and protecting vulnerable bursae:

• Good Skin Hygiene: Keep skin clean and promptly clean and cover any cuts, scrapes, or abrasions, especially over superficial bursae.
• Protect Vulnerable Bursae: Use protective padding (e.g., knee pads, elbow pads) during activities that involve repetitive pressure, friction, or direct trauma to the knees or elbows.
• Manage Underlying Health Conditions: Effectively manage chronic conditions like diabetes or skin disorders that can compromise immune function or skin integrity.
• Avoid Direct Trauma: Be mindful of activities that could cause skin breaks or direct impact to bursae.
• Proper Wound Care: If a wound occurs, ensure it is cleaned and dressed appropriately to prevent bacterial entry.

When to Seek Medical Attention

Septic bursitis is a medical emergency. You should seek immediate medical attention if you experience:

• Rapidly worsening pain, redness, warmth, and swelling around a joint.
• Fever, chills, or a general feeling of being unwell (malaise) accompanying localized inflammation.
• Any skin break or wound over a bursa followed by signs of infection.
• Persistent or increasing pain and swelling despite home care for suspected bursitis.

Conclusion

Septic bursitis is a serious and potentially dangerous bacterial infection of a bursa sac. Unlike its aseptic counterpart, it requires prompt diagnosis, typically confirmed by bursa fluid aspiration, and aggressive treatment with antibiotics and often drainage. Understanding the anatomy, causes, risk factors, and characteristic symptoms is vital for fitness professionals and enthusiasts alike. Early recognition and swift medical intervention are paramount to prevent complications such as cellulitis, osteomyelitis (bone infection), and systemic sepsis, ensuring a favorable outcome and preserving joint function.