Countercoup Skull Fracture
Countercoup is a main mechanism of injury in trauma patients. For head injuries, countercoup injuries commonly affect the brain tissue and cause diffuse axonal damage (Jacobsen et al., 2009). However, with significant trauma, countercoup injuries may cause skull fractures. Countercoup fractures are those that occur in an area of the skull that is the opposite of the side that received the implicated blow. A blow to any side of a moving skull causes a sudden change in speed and direction of the brain’s movement. The brain matter thus causes a secondary blow on the opposite side of the skull that has come to a sudden halt; this secondary blow is sufficient enough to cause a counter-coup fracture (Jacobsen et al., 2009). These type of fractures commonly occur in patients where the initial trauma was in the occipital region; they are thus common in the anterior cranial fossa. A few patients might have these fractures in their middle cranial fossae. Countercoup fractures can occur with or without an associated fracture of the area that received the blow. In most instances, patients with such fractures have diffuse axonal damage, cerebral edema, subdural hemorrhage, epidural hemorrhage or subarachnoid hemorrhage. This paper discusses the diagnostic approach to a patient with an evident countercoup skull fracture in the anterior cranial fossa.
The image below is a radiograph of a 31-year old male patient taken upon arrival at the hospital after he had sustained blunt trauma to the back of his head:
The image is a lateral projection of the skull. In my opinion, the image is of high quality and one can use it for diagnostic purposes. This opinion is due to the image’s clear reproduction of the inner and outer lamina of the cranial vault, the apex of the petrous bone, and the sella turcica (Bath and Mansson, 2007). The contours of the anterior cranial fossa are also visible thus making it possible to identify the fracture. The radiograph also sharply reproduces the vertex of the skull and the trabecular structure of the skull. The radiograph also shows clear superimposition of the mandibular angle on the ascending rami.
For this patient, a physical examination is of great importance as it can aid in the identification of neurological complications (Zyluk et al., 2013). For a patient with a fracture in the anterior cranial fossa, physical examination should focus on the assessment of the visual and olfactory functions. Moreover, it is important to assess cognitive functions to either rule out or identify damage to the frontal lobe. As such, open communication with the patient and the care provider is important – it is through communication that one can identify if the patient has speech, cognitive or memory problems. Additionally, the physical examination should focus on identification of any extra bone deformities. However, this examination should be gentle to prevent aggravation of the fractures of associated hemorrhage. It is safe to examine the patient after initial images. It is critical to assess the patient further by using other X-ray projections, CT scans, and MRI scans. It is important to position the patient such that it will be easier to identify life-threatening conditions and to allow them to breathe well without aggravating the fracture. Moreover, providers should consider the possibility of the patient suffering seizures and prepare to prevent resultant falls.
References
Bath, M., & Mansson, L. G. (2007). Visual grading characteristics (VGC) analysis: a non-parametric rank-invariant statistical method for image quality evaluation. The British journal of radiology, 80(951), 169-176. https://doi.org/10.1259/bjr/35012658
Jacobsen, C., Bech, B. H., & Lynnerup, N. (2009). A comparative study of cranial, blunt trauma fractures as seen at medicolegal autopsy and by computed tomography. BMC medical imaging, 9(1), 18. https://doi.org/10.1186/1471-2342-9-18
Żyluk, A., Mazur, A., Piotuch, B., & Safranow, K. (2013). Analysis of the reliability of clinical examination in predicting traumatic cerebral lesions and skull fractures in patients with mild and moderate head trauma. Polish Journal of Surgery, 85(12), 699-705. doi: 10.2478/pjs-2013-0107.
