Is ertapenem (a broad-spectrum antibiotic) medically necessary for a patient with hidradenitis suppurativa (L73.2) and severe sepsis without septic shock (R65.20)?

Is Ertapenem Medically Necessary for This Patient?

Yes, ertapenem is medically necessary and strongly indicated for this patient with severe hidradenitis suppurativa complicated by severe sepsis, active purulent drainage, and recent surgical intervention in a quadriplegic patient. 1

Rationale for Medical Necessity

Primary Indication: Severe Sepsis Without Septic Shock (ICD-10: R65.20)

• Ertapenem is explicitly recommended for severe, recalcitrant hidradenitis suppurativa cases according to the 2025 North American Clinical Practice Guidelines, with conditional recommendation and moderate quality evidence 1
• The presence of severe sepsis (R65.20) with visible purulent drainage from recent surgical wounds represents a life-threatening complication requiring broad-spectrum IV antibiotic coverage 1
• This patient's quadriplegia with quadriparesis creates additional infection risk due to immobility, impaired immune surveillance, and difficulty with wound care 2

Disease Severity Assessment

• This represents Hurley Stage III disease based on the clinical description: extensive involvement of both buttocks and mid-lower back, recent surgical intervention, ongoing purulent drainage, and chronic recurrent nature 1
• The extensive anatomical involvement ("encompassing both buttocks in its entirety as well as the mid lower back skin") indicates severe, recalcitrant disease that has failed multiple prior treatments including antibiotics, Cosentyx (secukinumab), and laser hair removal 1
• Active suppuration with visible pus drainage upon minimal expression indicates acute bacterial superinfection requiring immediate IV antibiotic intervention 3, 2

Evidence Supporting Ertapenem Use

Guideline-Based Recommendations

• The 2025 North American Guidelines specifically recommend IV ertapenem for severe, recalcitrant HS cases with moderate quality evidence 1
• The 2019 North American Guidelines include ertapenem in the therapeutic algorithm for severe disease management 1
• Ertapenem provides broad-spectrum coverage against the polymicrobial anaerobic bacteria typically colonizing severe HS lesions 3

Clinical Efficacy Data

• A 2016 pilot study of 30 consecutive severe HS patients demonstrated dramatic improvement with ertapenem 1g daily for 6 weeks, with median Sartorius scores dropping from 49.5 to 19.0 (P < 10^-4) 3
• A 2024 retrospective review of 98 patients treated with ertapenem for 12-16 weeks showed significant reductions in HS Physician Global Assessment scores (3.9 vs 2.7, P < 0.001), pain scores (4.2 vs 1.8, P < 0.001), and inflammatory markers including CRP and IL-6 2
• Patient satisfaction was high, with 80.3% reporting medium to high satisfaction and 90.8% willing to recommend ertapenem to other patients 2

Recommended Treatment Protocol

Dosing and Duration

• Administer ertapenem 1g IV daily via peripheral intravenous central catheter (PICC line) with elastomeric pump for home administration 2
• Treatment duration should be 6-16 weeks based on clinical response, with most studies showing optimal results at 12-13 weeks 3, 2
• Continue until resolution of active infection, closure of draining wounds, and normalization of inflammatory markers 3, 2

Monitoring Parameters

• Assess clinical severity using HS Physician Global Assessment and pain scores at baseline, mid-course, end of treatment, and post-therapy 2
• Monitor inflammatory markers: leukocyte count, ESR, CRP, and IL-6 levels 2
• Evaluate for antimicrobial resistance given longer-than-standard treatment course 2
• Screen for ertapenem-related adverse effects including rash, GI symptoms, and seizures (particularly relevant given this patient's neurological condition) 4

Consolidation Therapy

• Consolidation treatments are mandatory after ertapenem to prevent relapse - patients who interrupted consolidation therapy experienced return to baseline disease severity 3
• Consider transitioning to oral antibiotics (clindamycin 300mg BID + rifampin 300-600mg daily) or biologic therapy (adalimumab 40mg weekly) for maintenance 1, 5
• The patient's prior use of Cosentyx (secukinumab) suggests biologic therapy has been attempted; adalimumab may be more appropriate as it has stronger evidence for HS 1, 6

Critical Caveats for This Specific Patient

Quadriplegia Considerations

• Immobility significantly increases infection risk and impairs wound healing, making aggressive antibiotic therapy even more critical 7
• Coordinate wound care with nursing staff and family members given patient's inability to perform self-care 7
• Consider pressure ulcer prevention strategies as this patient is at extremely high risk 7

Sepsis Management

• The presence of severe sepsis (R65.20) makes this an urgent medical necessity - delay in appropriate antibiotic therapy increases mortality risk 8
• Ensure adequate source control through continued wound drainage and debridement as needed 8
• Monitor for progression to septic shock requiring ICU-level care 8

Surgical Coordination

• Recent surgical intervention with ongoing purulent drainage indicates inadequate source control - ertapenem should be combined with surgical optimization 3, 9
• Radical excision with skin grafting or flap reconstruction may ultimately be required for definitive management, but medical stabilization with ertapenem is necessary first 9
• The 2005 study showed 69.88% recurrence rate with primary closure alone, emphasizing need for both aggressive medical and surgical management 9

Criteria Used for This Decision

Primary Criteria:

• ICD-10 L73.2 (Hidradenitis Suppurativa) - Hurley Stage III severity based on extensive anatomical involvement and chronic recurrent nature 1
• ICD-10 R65.20 (Severe Sepsis Without Septic Shock) - Active systemic infection requiring broad-spectrum IV antibiotics 1, 8

Supporting Criteria:

• 2025 North American Clinical Practice Guidelines recommendation for IV ertapenem in severe, recalcitrant HS (Conditional recommendation, Moderate quality evidence) 1
• Failed multiple prior therapies including oral antibiotics, biologic therapy (Cosentyx), and laser hair removal 1
• Active purulent drainage from surgical wounds indicating acute bacterial superinfection 3, 2
• High-risk patient population (quadriplegic with limited mobility and self-care ability) 7

Outcome Prioritization:

• Mortality risk: Severe sepsis carries significant mortality risk that ertapenem directly addresses 8
• Morbidity reduction: Ertapenem has demonstrated significant reduction in disease severity, pain, and inflammatory markers 3, 2
• Quality of life: 80.3% patient satisfaction and 90.8% willingness to recommend treatment indicates meaningful QOL improvement 2