Synopsis
Recognise cranial and spinal cerebrospinal-fluid leakage, separate traumatic from postoperative and spontaneous causes, and prevent ascending infection without unsupported antibiotic prophylaxis.
- Classify the leak before applying evidence: traumatic skull-base, postoperative cranial, spontaneous skull-base and spinal or post-dural-puncture leaks have different investigations and repair pathways.
- Traumatic clear rhinorrhoea or otorrhoea is a basal-skull-fracture sign; NICE requires CT head within one hour across its age-specified head-injury pathway.
- Fluid biomarkers such as beta-2 transferrin or beta-trace protein can support that a cranial discharge contains CSF, while thin-slice CT and MRI help localise the defect; availability and interpretation are laboratory-specific.
Key red flags
Clear nasal or ear discharge after trauma, Battle sign, periorbital bruising, haemotympanum or cranial-nerve deficit requires urgent skull-base assessment.
Fever, severe headache, neck stiffness, photophobia, altered consciousness or seizure with a known leak may represent meningitis and needs immediate sepsis and meningitis treatment.
A high-flow postoperative leak, wound leak, enlarging pseudomeningocele or neurological decline needs urgent surgical-team review rather than routine outpatient observation.
Orthostatic headache with diplopia, hearing change or neurological deficit after dural puncture may represent spinal CSF loss; thunderclap onset or reduced consciousness demands alternative emergency diagnoses.
Unilateral clear watery rhinorrhoea or otorrhoea, salty postnasal taste and flow affected by posture raise suspicion, especially after trauma or surgery.
Fever, neck stiffness, headache, photophobia, confusion or seizure in a person with a cranial fistula requires immediate infection management.
Reasoning priorities
Detect skull-base fracture, intracranial haemorrhage, pneumocephalus and other acute head-injury complications.
CSF leakage from ear or nose itself satisfies the NICE basal-skull-fracture imaging criterion; stabilisation and escalation proceed in parallel.
Worked reasoning
A patient has clear unilateral nasal discharge plus signs compatible with skull-base trauma.
- Context: stabilise airway, breathing and circulation; document GCS, pupils, cranial nerves, otoscopy, associated bleeding and infection features without asking the patient to strain.
- Reasoning: regard CSF rhinorrhoea as a basal-skull-fracture sign and obtain CT head within one hour under NICE, while seeking early trauma, ENT and neurosurgical advice.
- Outcome: avoid routine prophylactic antibiotics; use therapeutic antimicrobials only if infection is suspected, and address pneumococcal vaccination eligibility under current UK criteria.
- Verification: follow leak persistence and neurological state; if traumatic leakage continues beyond seven days, IDSA supports repair, with technique chosen by the skull-base team.