Bilateral isodense epidural hematoma: case report

Hematoma epidural isodenso bilateral: relato de caso

Bilateral isodense epidural hematoma: case report

Hematoma epidural isodenso bilateral: relato de caso

Rodrigo Mendonça^I; Telmo T.F. Lima^I; Leandro I. Dini^II; Cláudio L.L. Krebs^II

Neurosurgery Department of Hospital Cristo Redentor, Porto Alegre, RS, Brazil

^IMD, Resident

^IIMD Neurosurgeon

ABSTRACT

We present a case of a severe head injuried 23 year-old male patient. The initial CT scan disclosed bilateral epidural hematoma, isodense with the brain, thus being a pitfall in diagnosis. Brief case report, image and literature rewiew are presented.

Key words: epidural hematoma, head injury, computed tomography.

RESUMO

Apresentamos o caso de um homem de 23 anos com traumatismo craniano grave. A TC de crânio demonstrou um volumoso hematoma epidural bilateral, isodenso com o cérebro, sendo uma armadilha ao diagnóstico. São apresentados um breve relato, estudo da imagem tomográfica e revisão da literatura.

Palavras-chave: hematoma epidural, trauma craniano, tomografia computadorizada.

The computerized tomography (CT) scan of epidural hematomas usually show hyperdense biconvex shaped mass lesions. Isodense epidural hematomas are rare features with few cases reported in the neurosurgical literature^1-3. Different theories have been proposed to explain this atypical radiological finding, from low hematocrit values to dilution of the epidural blood due to mixture with cerebrospinal fluid (CSF).

We present a case in which a bilateral epidural hematoma was isodense with the brain and could be easily misdiagnosed, leading to unapropriate treatment.

CASE

A 23-year-old man arrived the emergency room 3 hours after suffering head injury due to an assault, with conciousness impairment. There was a history of alcohol ingestion and the initial GCS (glasgow coma score) was 14. There were not clinical signs of skull base fracture. The patient presented a rapid clinical deterioration to comatous state and required intubation. A CT scan was performed at this moment (Fig 1), and showed large bilateral isodense epidural hematomas. He was rapidly transferred to the operating room with GCS score 4 and dilated pupils. At this moment blood tests showed a hematocrit 29.4%, hemoglobin 9.6 g/dl and normal coagulation studies. A bicoronal incision was made, with bilateral temporal craniectomy. Operative findings included partially clotted bilateral epidural hematomas and an extensive skull base fracture, with active bleeding from the inner ear. There was no dural laceration. The patient had a favorable outcome, with remarkable clinical improvement in the immediate post-operative period, being discharged in good neurological condition (GOS 5) after 19 days.

DISCUSSION

Isodense epidural hematomas are rare radiological findings. In the series of 151 patients reported by Tapiero et al., 40% presented hyperacute epidural hematomas but none of these were isodense with the brain⁴. The densities of subdural and epidural hematomas on CT scans are related to the attenuaton values of the clot, as a function of the erythrocyte and hemoglobin protein concentration and in a lesser extent related to the iron content of the hemoglobin molecule⁵. Serum hemoglobin concentrations ranging from 9 to 11 g/dl have approximately the same density of the brain on CT scans. The clotting mechanisms are not essential for the CT attenuation, but clot retraction with separation of serum and absorption of fluid acts increasing the focal hemoglobin concentration and the density of acute clots¹.

The "hyperacute" extradural hematomas are usually hyperdense, with some small areas iso or hypodense within the lesion⁴. The possible causes of these combined densities are the presence of fresh, unclotted blood (which has a low attenuation coefficient), a low hematocrit or a mix of blood with CSF due to dural lacerations. Another proposed mechanism is the continuous washout of the blood within the hematoma throught the diploic veins after a skull fracture⁴.

In the present case, the CT findings could be explained by the anemia or by the presence of the skull base fracture. The dura was intact, thus the isodense hematoma could not be related to the CSF mixture.

It is important to state that early diagnosis and treatment of extra-axial traumatic hematomas may result in a important decline in morbidity and mortality and the misdiagnose is a potentially fatal situation. Neurosurgeons should be aware of the above discussed condition, so prompt recognition and treatment can be achieved with better outcomes.

Aknowledgements–Special thanks to the Dr. Marco Antonio Stefani and Dr. Álvaro Ernani Georg for the revision of this report.

Received 24 January 2005, received in final form 8 April 2005. Accepted 20 May 2005.

Dr. Rodrigo Mendonça - Serviço de Neurocirurgia do Hospital Cristo Redentor - Rua Domingos Rubbo 40 - 91040-000 Porto Alegre RS - Brasil. E-mail: [e-mail]

• 1. Arrese I, Lobato RD, Gómez PA, Nunez AP. Hyperacute epidural haematoma isodense with the brain on computed tomography. Acta Neurochir (Wien) 2004;146:193-194.
• 2. May PL, Miles JB. Acute isodense extradural haematoma. Br J Neurosurg 1989;3:221-224.
• 3. Rieth KG, Schwartz FT, Davis DO. Acute isodense epidural hematoma on computed tomography. J Comput Assist Tomogr 1979;3:691-693.
• 4. Tapiero B, Richer E, Laurent F, Guibert-Tranier F, Caille M. Post-traumatic extra-dural haematomas. J Neuroradiol 1984;11:213-226.
• 5. Greenberg J, Cohen WA, Cooper PR. The "hyperacute" extraaxial intracranial hematoma: computed tomographic findings and clinical significance. Neurosurgery 1985;17:48-56.

Publication Dates

• Publication in this collection
  02 Mar 2006
• Date of issue
  Sept 2005

History

• Accepted
  20 May 2005
• Received
  24 Jan 2005