Medical Surgical Head Injury #2

Question

The nurse is assessing a client following a fall from two stories high. The nurse immediately contacts the health provider after finding clear nasal drainage indicative of basilar skull fracture. Which of the following findings alerts the nurse to determine that the clear nasal drainage is cerebrospinal fluid?

Answers

  1. The fluid is completely dark red and bloody with pH of 6.
    • Rationale:

      This answer is not correct because CSF may have some blood, but usually not fully bloody. CSF will not have a pH as low as 6.

  2. Fluid has yellow thick clumps with pH of 8.
    • Rationale:

      This answer is not correct because CSF will not have thick yellow clumps. Also, pH is usually between 7.28 – 7.32.

  3. Fluid is clear and tests negative for glucose.
    • Rationale:

      This answer is not correct because although CSF fluid is clear, so is normal nasal drainage. The difference is that this fluid tested negative for glucose, indicating it is not CSF.

  4. Fluid separates into rings and is positive for glucose.
    • Rationale:

      This answer is correct because drainage of spinal fluid on the dressing material may produce a ‘halo sign’ that appears like concentric rings and may separate into yellow or blood tinged rings. The fluid will also be positive for glucose. Nasal drainage has little glucose whereas CSF fluid from the nasal area may have levels between 40 – 70 mg/dL.

Overview

A basilar skull fracture is a very serious head injury that results in a break at the base of the skull. A common sign of this type of fracture is clear nasal drainage that separates into rings and is positive for glucose.

Explanation

Learning Outcomes

CSF protects the brain inside the skull, acting as a buffer from impact. It also supplies nutrients to the brain and spinal cord. Skull fractures can cause a tear into the dura mater and cause CSF to leak out into spaces and drain through the ears or nose. The CSF fluid mixes with blood, and the elements of the fluid separate and form rings or a “halo”. When the drainage tests positive for glucose, it is indicative of CSF. Treatment used is an epidural blood patch, which is an injection of the client’s blood into the epidural space, thus forming a clot and sealing the leak.

Test Taking Tip

Knowing the pH values of water, blood, and saliva would aid in answering this test question. Also remember that CSF contains glucose.

Video Rationale