Do you give antibiotics (abx) to patients with a subdural hematoma and a skull fracture?

Antibiotic Prophylaxis for Subdural Hematoma with Skull Fracture

Do not routinely administer prophylactic antibiotics for subdural hematomas with skull fractures, as current evidence does not support this practice for closed head injuries without signs of infection. 1, 2

Key Decision Points

Blunt Trauma with Closed Skull Fracture

• Antibiotics are NOT recommended for blunt trauma in the absence of sepsis or septic shock, even when skull fractures are present 1
• This recommendation applies specifically to closed injuries where there is no penetration or open wound 1
• The 2024 World Society of Emergency Surgery guidelines provide strong evidence (1B) against antibiotic administration in this scenario 1

Basilar Skull Fractures Specifically

• Prophylactic antibiotics do not prevent meningitis in patients with basilar skull fractures, regardless of whether cerebrospinal fluid (CSF) leakage is present 2, 3
• A Cochrane systematic review of 5 RCTs (208 participants) and 17 non-RCTs (2,168 patients) found no significant reduction in meningitis frequency, all-cause mortality, or meningitis-related mortality with antibiotic prophylaxis 2
• The odds ratio for meningitis prevention was 1.15 (95% CI 0.68-1.94), indicating no benefit 3

When Antibiotics ARE Indicated

Start therapeutic antibiotics immediately if:

• Signs of infection develop (fever, purulent drainage, elevated inflammatory markers) 4, 5
• The patient presents with sepsis or septic shock 1
• There is penetrating trauma to the head 1
• An open skull fracture with scalp laceration is present 1

For infected subdural collections:

• Use therapeutic-dose antibiotics, not prophylactic doses 4, 5
• Common organisms include Streptococcus pneumoniae and Enterococcus faecalis 4, 5
• Surgical drainage is typically required in addition to antibiotics 4, 5

Critical Pitfalls to Avoid

• Do not automatically prescribe antibiotics for all skull fractures with subdural hematomas—this exposes patients to unnecessary antibiotic resistance risk and adverse effects without proven benefit 2, 3
• Do not confuse prophylaxis with treatment—if infection develops (fever, worsening mental status, elevated WBC), switch immediately to therapeutic-dose antibiotics and consider surgical intervention 4, 5
• Monitor closely for delayed infection—infected subdural collections can develop days after initial injury, particularly if there was scalp trauma creating a potential bacterial entry point 4
• Recognize that CSF leakage does not change the recommendation—even with documented CSF leak from basilar skull fracture, prophylactic antibiotics remain ineffective 2, 3

Special Circumstances

Open Fractures Requiring Surgery

If the skull fracture requires operative fixation (open reduction internal fixation), then standard surgical prophylaxis applies:

• Administer cefazolin 2g IV within 60 minutes before incision 6
• For penicillin allergy: clindamycin 900mg IV or vancomycin 30mg/kg IV over 120 minutes 6
• Limit prophylaxis to 24 hours postoperatively 6

High-Risk Patients

Consider antibiotics in elderly patients with subdural hematoma and skull fracture who are:

• Immunocompromised 1
• Obese 1
• High ASA score 1

However, this should be based on clinical signs of infection rather than prophylaxis alone 1