In a patient with suspected sepsis secondary to a penile prosthesis infection, what diagnostic workup should be performed?

Diagnostic Workup for Suspected Sepsis from Penile Implant Infection

In a patient with suspected sepsis from a penile prosthesis infection, immediately obtain at least 2 sets of blood cultures (aerobic and anaerobic), ESR and CRP, plain radiographs, and consider device aspiration if feasible—all before initiating antibiotics if the patient is stable enough to tolerate a brief delay.

Initial Clinical Assessment

Focus your history on 1:

• Date of implant placement and type of prosthesis
• Timing of symptom onset (pain, fever, wound drainage, erythema)
• Prior wound healing complications or superficial infections
• Previous cultures and antimicrobial therapy
• Remote infections and comorbidities (particularly diabetes, smoking status)
• Drug allergies

Physical examination should specifically assess for 1:

• Sinus tract or persistent wound drainage over the prosthesis
• Local signs of infection (erythema, warmth, tenderness)
• Systemic signs of sepsis (fever, hypotension, altered mental status)

Laboratory Workup

Blood Work (Priority Order)

1. Blood cultures: Obtain at least 2 sets (aerobic and anaerobic bottles) before antibiotics if patient is stable 1, 2

   • Draw at least one percutaneously
   • If vascular access devices present, draw one through each device unless recently inserted (<48 hours)
   • Critical timing: If septic shock is present, do not delay antibiotics >1 hour for cultures 2

2. Inflammatory markers: ESR and CRP 1

   • The combination provides optimal sensitivity and specificity for prosthetic infection
   • Elevated levels support infection diagnosis but are not specific

3. Lactate level 2

   • Prognostic marker for tissue hypoperfusion and microcirculatory failure
   • Use for risk stratification and resuscitation guidance

4. Consider procalcitonin 3, 4

   • Useful for infectious disease management and antimicrobial stewardship
   • Can help differentiate bacterial infection from other inflammatory processes

Device-Specific Sampling

Aspiration of the prosthesis/surrounding tissue (if technically feasible and patient stable) 1:

• Send fluid for cell count with differential
• Culture for aerobic and anaerobic organisms
• Withhold antibiotics for at least 2 weeks prior if patient is medically stable to increase organism recovery 1
• However, in septic patients, this is not practical—prioritize immediate antimicrobial therapy

Important caveat: Unlike joint prostheses where arthrocentesis is standard, penile prosthesis aspiration may not be routinely feasible. The principles from prosthetic joint infection guidelines 1 apply conceptually, but practical application differs.

Imaging Studies

1. Plain radiographs of the pelvis/implant area 1

   • Look for device migration, gas in soft tissues, or hardware abnormalities

2. Advanced imaging is NOT routinely recommended 1

   • CT, MRI, bone scans, and PET scans should not be used routinely for diagnosis
   • May be considered if source control planning requires anatomic detail

Microbiological Considerations

Expected organisms based on recent data 5, 6, 7:

• Gram-positive bacteria (most common): Staphylococcus epidermidis, S. aureus (31.5-66% of cases)
• Gram-negative bacteria: 22-33% of cases
• Fungal organisms: 11-33% of cases (increasingly recognized)
• Anaerobes: 4% of cases
• No growth cultures: 30% of cases (biofilm-related)

Critical Timing Issues

• Antibiotic administration: Within 1 hour of sepsis recognition 2
• Source control: Plan for device removal/salvage within 6-12 hours if septic 3
• Median time to infection presentation: 1.8 months post-implantation 7, though can occur at any time

Common Pitfalls to Avoid

1. Do not delay antibiotics beyond 1 hour in septic shock to obtain cultures 2
2. Do not rely on advanced imaging (bone scans, leukocyte scans) for diagnosis—they lack specificity 1, 8
3. Do not assume negative cultures rule out infection—biofilm-associated infections frequently have negative cultures 6, 7
4. Do not forget fungal coverage consideration—fungal infections represent up to 33% of salvage cultures 5

Hemodynamic Assessment in Septic Shock

If patient presents with septic shock 2:

• Target mean arterial pressure ≥65 mmHg
• Use dynamic variables to predict fluid responsiveness
• Normalize lactate as resuscitation goal
• Consider further hemodynamic assessment if shock type unclear

The workup must be rapid and focused, with cultures obtained immediately but never delaying antibiotics beyond 1 hour in septic patients. Device removal or salvage should be planned urgently as definitive source control 3, 9.