Primary Blast Injury

Answer D. Urgent consult to otolaryngology (ENT)

The teenager has suffered a primary blast injury to his eardrum.

There is a significant disruption of the tympanic membrane (eardrum) which is circled in this image.

Blast injuries are classified as follows;

• Primary – from the pressurization wave of the blast. Primary injuries present to the lung, eye, eardrum (as in this case), abdomen and brain.
• Secondary – from flying debris. Secondary injuries can occur anywhere. An example would be penetrating injury from metal that was surrounding a bomb. The individuals who were injured at the Boston Marathon bombing suffered secondary blast injuries.
• Tertiary – from the individual being thrown by the blast. Tertiary injuries present as orthopedic or traumatic brain injuries.
• Quaternary – explosion related. Examples of quaternary injuries include burns, crush injuries, asthma exacerbations from dust storms, and radiation exposure.

Minor tympanic membrane ruptures generally heal on their own. In this case, the damage is significant, clearly affecting where the malleus attaches to the tympanic membrane. This patient needs an urgent consultation with otolaryngology (ENT). The decision to start medication would be guided by a stat consult with ENT but is generally not indicated. The patient should be told to avoid any moisture in the ear until evaluated by ENT. He will likely need surgical intervention to repair the extensive damage to both the tympanic membrane and the middle ear structures.

Key Learning Points:

1. Tympanic membrane ruptures are common and can occur from insertion of foreign objects, blasts, and diving.
2. Small ruptures often heal on their own and do not require intervention. Large or complex ruptures require ENT evaluation.
3. Antibiotics are generally not indicated for a clean rupture.
4. Water such as found in a pond, lake or pool should be avoided until seen by ENT.

WiscMed thanks Dr. Patricia Padlipsky of Harbor-UCLA for contributing this interesting image.

Reference

Mathews ZR, Koyfman A. Blast Injuries. J Emerg Med. 2015 Oct;49(4):573-87. doi: 10.1016/j.jemermed.2015.03.013. Epub 2015 Jun 10. PMID: 26072319.