Keywords
epidural hematoma - contrecoup - head injuries
Introduction
Epidural hematoma (EDH) usually occurs as a result of direct impact injuries of the
head, ipsilateral to impact side. These are frequently associated with local scalp
bruise or occur beneath the fracture site, although occasional epidural hematoma without
skull fractures have been reported.[1] EDH may occur in 1% of patients with head injury.[2]
[3] The peak incidence of EDH is in the second decade, with a mean age of 20 to 30 years,
and it is rare in patients older than 50 to 60 years.[4] Contrecoup EDH cases are rare,[2] and only 10 cases have been reported in the literature on extensive search. Herein,
because of rarity of EDH, we report a case of contrecoup EDH with pneumocephalus in
the right frontal region associated with left occipital bone fracture.
Case Report
A 17-year-old boy was referred to us from a district hospital with history of road
traffic accident 18 hours earlier. He has been disoriented since the injury, with
history of two episodes of vomiting, but no history of seizures, bleeding from the
ear, nose, or throat. On examination, a stitched lacerated wound of 5 cm over the
left occipital region was present. His Glasgow coma scale (GCS) score was 14. Pupils
were bilaterally semidilated and reacting, with pulse rate 58 beats/min. Computed
tomography (CT) scan revealed large epidural hematoma in right frontal region with
associated small pneumocephalus and hemorrhagic contusional edema beneath it with
left occipital bone fracture ([Fig. 1A, B]). The patient was immediately operated upon after preparation, and a right frontal
craniotomy with evacuation of extradural hematoma was performed. No fracture was present
intraoperatively in the right frontal region. Postoperative CT scan was done, which
showed postoperative changes ([Fig. 1C, D]). Mannitol was administered in the postoperative period. His GCS improved to 15
in the second postoperative day, and the patient was discharged uneventfully.
Fig. 1 (A, B) CT scan showing large epidural hematoma in right frontal region with associated
small pneumocephalus and hemorrhagic contusional edema beneath it with left occipital
bone fracture. (C, D) Postoperative CT scan showing postoperative changes. CT, computed tomography.
Discussion
Incidence of extradural hematoma is 1 to 3% of all head injuries.[1] Mortality rate varies from 10 to 40% and is an index of alertness and efficiency
of health care and hospital setup.[2] Blunt head trauma is the most frequent cause of EDH with a percentage range between
1 and 6%.[3] Although contrecoup contusions and acute subdural hematoma resulting from acceleration
injuries to the head have been reported, only 10 cases of contrecoup epidural hematoma
have been published in the literature.[1] The clinical-radiologic features of all the 11 cases including this case are summarized
in [Table 1].[4]
[5]
[6]
[7]
[8]
[9]
[10]
[11]
[12]
Table 1
Summary of cases of contrecoup epidural hematoma
|
Author (year)
|
Age/Sex
|
Site of impact
|
Fracture
|
Coup injury
|
Contrecoup injury
|
Operation for contrecoup EDH
|
Outcome
|
|
Abbreviations: D, death; EDH, epidural hematoma; F, female; GR, good recovery; M,
male.
|
|
Okamoto[5] (1983)
|
51/F
|
Occipital
|
–
|
–
|
Frontal EDH
|
+
|
GR
|
|
Shigemori[6] (1985)
|
43/M
|
Frontotemporal
|
+
|
–
|
Occipital EDH
|
+
|
GR
|
|
Hamasaki[7] (1987)
|
58/F
|
Occipital
|
+
|
Cerebellar contusion SDH (posterior fossa)
|
Frontal EDH
|
–
|
D
|
|
Abe[8] (1988)
|
36/M
|
Frontal
|
+
|
–
|
Occipital EDH
|
+
|
D
|
|
Miyazaki[9] (1995)
|
52/F
|
Occipital
|
+
|
Occipital EDH
|
Frontal EDH
|
+
|
GR
|
|
Motohashi[10] (2000)
|
59/F
|
Occipital
|
+
|
–
|
Frontotemporal contusion Frontal EDH frontal contusion
|
–
|
GR
|
|
Mishra[1] (2001)
|
50/M
|
Frontoparietal
|
+
|
Frontoparietal contusion
|
Frontoparietal EDH
|
+
|
GR
|
|
Mitsuyam[11] (2004)
|
50/F
|
Parietal
|
+
|
Parietal EDH
|
Frontal EDH
|
–
|
GR
|
|
Sato[11] (2009)
|
68/F
|
Occipital
|
+
|
Occipital EDH cerebellar contusion
|
Frontal EDH
|
–
|
GR
|
|
Takeuchi[4] (2010)
|
60/F
|
Occipital
|
+
|
cerebellar contusion
|
Frontal EDH
|
–
|
GR
|
|
Present case
|
17/M
|
occipital
|
+
|
–
|
Frontal EDH Pneumocephalus
|
+
|
GR
|
The mechanism of contrecoup EDH remains unclear. Dural separation and dural vessel
injury caused by distortion of the cranium brought on by the force of impact are possible
mechanisms that could contribute to the development of EDH.[4] According to Jamieson,[13] contrecoup epidural hematoma does not occur but can present as bilateral when midline
vessel of sagittal sinus is involved or multiple blows have been experienced. However,
later in 1991, an unusual type of bilateral epidural hematoma, one due to direct injury
and another due to the contrecoup effect has been reported by Balasubraminiam and
Ramesh.[14] They observed that local deformation at the site exactly opposite the impact site
gave rise to a small pocket brought on by stripping of dura. This deformation and
“reliance effect” produced by evacuation of first hematoma resulted in contrecoup
hematoma. Miyazaki et al[9] also reported a case of bilateral coup and contrecoup epidural hematoma. They concluded
that distortion of the cranium brought on by the force of impact leads to dural separation
resulting in hematoma.
This case showed a small air pocket besides the EDH, but intraoperatively and on imaging
there was no skull fracture at the frontal region and the base. This finding is also
supported by Choi et al[15] who has reported a case of pneumocephalus without a skull base fracture. Two mechanisms
have been proposed to explain pneumocephalus without craniofacial skull fracture,
both involving low intracranial pressures that result in the “sucking” of air through
a dural defect. The first mechanism involves vertical pressure that creates a pressure
gradient within the cerebrospinal fluid (CSF) system, whereas the second involves
a ball valve effect that allows air to enter the skull base through multiple foramen
or the craniocervical junction pathway.
Conclusion
Acute EDH is a neurosurgical emergency with high mortality. Contrecoup EDH is a rare
entity, but early diagnosis and timely treatment can lead to good prognosis. Most
of the cases reported in the literature have occurred in old-age group. In the present
case, contrecoup epidural hematoma was seen in younger age group, which is a rare
presentation. This case also presented with pneumocephalus with contrecoup EDH without
any fracture at the contrecoup site.
