PERICHONDRAL, CARTILAGINOUS, AND OSSEOUS INFECTIONS
PART A: PERICHONDRAL, CARTILAGINOUS, AND OSSEOUS INFECTIONS
These infections involve connective tissues, especially cartilage and bone, and are often serious, requiring long-term treatment.
Perichondral Infections
Infections involving the perichondrium, the connective tissue layer surrounding cartilage.
Common Sites:
- Ear (auricular perichondritis)
- Nasal septum
- Airway cartilage (tracheal perichondritis)
Causes:
- Trauma (e.g., ear piercing)
- Surgery or burns
- Infection spread from adjacent tissues
Common Pathogens:
- Pseudomonas aeruginosa (especially in ear infections)
- Staphylococcus aureus
- Streptococcus pyogenes
Clinical Features:
- Redness, swelling, pain over cartilage
- May progress to abscess or cartilage necrosis
Complications:
- Cartilage deformity (e.g., "cauliflower ear")
- Chronic infection
Diagnosis:
- Clinical examination
- Swab or aspirate for culture
- Imaging (if deep involvement suspected)
Treatment:
- Broad-spectrum antibiotics (e.g., fluoroquinolones)
- Surgical drainage if abscess forms
- Removal of necrotic cartilage
2. Cartilaginous Infections
Definition:
Infections directly involving the cartilage tissue itself.
Examples:
- Chondritis: Inflammation of cartilage, e.g., tracheal or costal cartilage
- Relapsing polychondritis: Autoimmune but may be complicated by secondary infection
Causes:
- Direct trauma
- Infected implants (e.g., joint replacements)
- Hematogenous spread (rare)
Common Organisms:
- S. aureus
- Pseudomonas spp.
- Anaerobes in post-surgical infections
Diagnosis and Treatment:
- Similar to perichondritis
- May need imaging (MRI) to assess cartilage
- Debridement plus antibiotics
3. Osseous Infections (Osteomyelitis)
Definition:
Osteomyelitis is an infection of bone tissue, which may be acute or chronic.
Types of Osteomyelitis:
|
Type |
Cause |
Notes |
|
Acute Hematogenous |
Spread via blood |
Common in children |
|
Contiguous |
From adjacent tissue (e.g., diabetic ulcer) |
Adults, especially with trauma |
|
Chronic Osteomyelitis |
Long-standing infection with necrotic bone |
May follow acute infection or surgery |
Common Sites:
- Long bones (femur, tibia) in children
- Vertebrae in adults
- Foot bones in diabetics
Common Pathogens:
|
Organism |
Notes |
|
Staphylococcus aureus |
Most common overall |
|
Streptococcus spp. |
Especially in children |
|
Pseudomonas aeruginosa |
IV drug users, puncture wounds |
|
Mycobacterium tuberculosis |
TB of spine (Pott’s disease) |
|
Salmonella spp. |
Seen in sickle cell anemia |
Clinical Features:
- Bone pain, fever, swelling
- Limited limb movement
- Draining sinus (chronic)
- Elevated CRP, ESR, leukocytosis
Diagnosis:
- Blood cultures
- Bone biopsy and culture (gold standard)
- Imaging:
- X-ray (late findings)
- MRI (early detection)
- Bone scan
Treatment:
- IV antibiotics for 4–6 weeks
- Surgical debridement of necrotic bone
- Removal of any infected hardware
- Amputation in severe diabetic foot infections
PART B: HOSPITAL-ASSOCIATED INFECTIONS (HAIs)
Definition
Hospital-associated infections (HAIs), also called nosocomial infections, are infections that:
- Occur 48 hours or more after hospital admission,
- Appear within 30 days after receiving healthcare (surgery, catheter use, etc.),
- Were not present or incubating at the time of admission.
Common Types of HAIs
|
Type |
Description |
Common Pathogens |
|
Catheter-Associated Urinary Tract Infections (CAUTIs) |
From urinary catheter use |
E. coli, Klebsiella, Pseudomonas, Enterococcus |
|
Ventilator-Associated Pneumonia (VAP) |
From mechanical ventilation |
Pseudomonas, Acinetobacter, S. aureus (MRSA) |
|
Surgical Site Infections (SSIs) |
After surgical procedures |
S. aureus, Streptococci, Enterobacteriaceae |
|
Central Line-Associated Bloodstream Infections (CLABSIs) |
From IV catheters |
Coagulase-negative Staphylococci, S. aureus, Candida |
|
Clostridioides difficile infection (CDI) |
Antibiotic-associated diarrhea |
C. difficile (spore-forming bacteria) |
Risk Factors for HAIs
- Prolonged hospitalization
- Invasive procedures (catheters, surgery)
- Broad-spectrum antibiotic use
- Immunosuppression
- Poor hand hygiene
- Overcrowded hospitals
Diagnosis of HAIs
- Clinical signs: Fever, discharge, localized pain
- Laboratory tests: Blood/stool/urine cultures
- Imaging: X-ray, ultrasound (as needed)
- Microbiological surveillance: To detect resistant organisms (e.g., MRSA, VRE)
Prevention and Control of HAIs
A. Standard Precautions
- Hand hygiene (soap or alcohol-based rubs)
- Use of personal protective equipment (PPE)
- Safe injection practices
- Environmental cleaning
B. Device Management
- Aseptic insertion and regular monitoring of catheters and IV lines
- Remove devices as soon as no longer needed
C. Antibiotic Stewardship
- Avoid overuse or misuse of antibiotics
- Use culture results to guide therapy
D. Surveillance and Isolation
- Early detection of resistant pathogens
- Isolation of infected or colonized patients
E. Staff Training
- Regular education on infection control practices
Treatment of HAIs
- Based on culture and sensitivity results
- Often require broad-spectrum antibiotics initially (e.g., meropenem, vancomycin), narrowed once pathogen is known
- May need removal of infected devices
Impact of HAIs
- Increased morbidity and mortality
- Prolonged hospital stay
- Increased healthcare costs
- Emergence of multidrug-resistant organisms (MDROs)
Perichondral, cartilaginous, and osseous infections are serious infections requiring early diagnosis, microbiological evaluation, and aggressive treatment. Meanwhile, hospital-associated infections represent a major public health challenge due to their preventable nature and their role in driving antimicrobial resistance. Prevention through strict infection control protocols and antimicrobial stewardship is essential.