Indications for Testing

• Presence of otorrhea or rhinorrhea; patient with recurrent episodes of meningitis

Laboratory Testing

• Chemical analysis (eg, Glucostix) of the fluid for glucose and protein is unreliable in determining the presence of CSF fluid
• The presence of beta-2 transferrin indicates CSF leakage (high specificity) – 0.5 cc fluid required to perform test
  • If positive perform imaging studies to identify area of leak
  • If negative but strong suspicion CT cisternography is test of choice
  • False positives suggest chronic liver disease or inborn errors of glycoprotein metabolism

Imaging Studies

• High resolution CT is initial study of choice
• MRI
• Cisternogram by CT or MRI
• Radiographic studies, with or without intrathecal injection of dye or radioisotope, are not always successful in demonstrating small or delayed CSF leaks

The leakage of cerebrospinal fluid (CSF) into nasal, oral or ear cavities or leakage from a dermal sinus and its subsequent drainage from these cavities may be the result of trauma, intracranial surgical procedures, infection, hydrocephalus, congenital malformations or neoplasms. The most severe consequence of a CSF leak is microorganism contamination and the development of meningitis.

Epidemiology

• Prevalence – 70-80% are related to accidental trauma
  • 2-4% of head injuries result in CSF leaks
• Age – middle age for spontaneous leaks, newborn for dermal sinus leakage
• Sex – M<F for spontaneous leaks

Etiology

• Trauma
• Nontraumatic
  • Surgery (usually spinal or neurosurgery)
    • Postoperative defect
  • Infection
  • Tumor obstruction
  • Congenital defects at the base of the skull or at the end of the spinal cord
  • Hydrocephalus
  • Spontaneous – no known defect or trauma

Pathophysiology

• Beta-2 transferrin, a protein produced by neuraminidase activity in the brain, is uniquely found in CSF and perilymph fluid
• Interruption of the anterior cranial fossa floor allows leaks of CSF through the cribriform plate
• 80% of post-traumatic leaks occur ≤48 hours post-trauma
• Presence of beta-2 transferrin in nasal or ear fluid highly suggestive of CSF leak

Clinical Presentation

• CSF leakage most commonly presents as otorrhea or rhinorrhea
• Patient may complain of salty or sweet taste; intermittent clear nasal discharge exacerbated by Valsalva maneuver
  • Most often unilateral drainage
• Presence of halo sign on used tissues or bed linen

Tests generally appear in the order most useful for common clinical situations

General

• Abuabara A. Cerebrospinal fluid rhinorrhoea: diagnosis and management. Med Oral Patol Oral Cir Bucal. 2007; 12 (5) :E397-E400.PubMed
• Bullock R, Soares D. Current imaging of cerebrospinal fluid leaks. West Indian Med J. 2009; 58 (4) :362-366.PubMed
• Gorogh T, Rudolph P, Meyer JE, Werner JA, Lippert BM, Maune S. Separation of beta2-transferrin by denaturing gel electrophoresis to detect cerebrospinal fluid in ear and nasal fluids. Clin Chem. 2005; 51 (9) :1704-1710.PubMed
• Kerr JT, Chu FW, Bayles SW. Cerebrospinal fluid rhinorrhea: diagnosis and management. Otolaryngol Clin North Am. 2005; 38 (4) :597-611.PubMed
• Lloyd KM, DelGaudio JM, Hudgins PA. Imaging of skull base cerebrospinal fluid leaks in adults. Radiology. 2008; 248 (3) :725-736.PubMed
• Wise SK, Schlosser RJ. Evaluation of spontaneous nasal cerebrospinal fluid leaks. Curr Opin Otolaryngol Head Neck Surg. 2007; 15 (1) :28-34.PubMed

Meningitis, Acute