Presentation
Head injury
Patient Data
Minimally displaced left parietal calvarial fracture is seen extending distally, involving the left temporal bone to the level of the zygomatic arch (does not traverse the region of the middle meningeal artery). Overlying this is a moderate-sized subgaleal hematoma and intracranially, there is a combination of subdural and subarachnoid blood demonstrated overlying the left cerebral hemisphere. The subdural collection measures up to 9mm in maximal depth while subarachnoid blood is seen extending into the left frontal, parietal and to a lesser degree temporal lobe sulci. No evidence of acute intraparenchymal hemorrhage.
There is secondary moderate left sided mass effect causing underlying sulcal effacement as well as partial effacement of the left lateral ventricle and secondary contralateral hydrocephalus. Approximately 3.5 millimeter rightward midline shift is also noted.
4mm left frontal subdural hematoma overlies the orbital roof.
Incidental cavum septum pellucidum noted.
The patient went on to have a craniotomy.
Left parietal fracture, parietal craniotomy and evacuation of the subdural hematoma which now has a maximum depth of 3 mm, previously 10 mm. Right frontal hemorrhagic contusions have significantly increased in size with surrounding edema. The volume of subarachnoid hemorrhage is stable with blood now pooling in the occipital horns. Subdural hematoma along the floor of the anterior cranial fossa is again noted. Ventricular size is stable.
Right frontal ICP in situ. There is a small volume of pneumocephalus.
The patient was recovering but had fluctuating mental state and intermittent fevers.
Comparison made to the previous CT scans.
The hematoma in the left anterior frontal lobe has a peripherally enhancing rim and measures 3 x 3 cm in axial dimension and a second hematoma in the posterior frontal lobe also enhances peripherally measuring 3 x 2.5 cm. There is a third subtle peripherally enhancing lesion in the inferomedial left frontal lobe measuring
1 x 1 cm and a 1cm lesion in the inferomedial right frontal lobe with equivocal enhancement. There is also increasing gyral enhancement through the left frontal and temporal lobe and increasing adjacent white matter edema. Mild effacement of the left lateral ventricle with 4mm midline shift to the right.
Left frontal craniotomy. A small underlying collection measures up to 3mm in depth. There are also bifrontal low density subdural collections measuring up to 8mm on the left and 5mm on the right with no convincing enhancement.
Extensive mucosal thickening and fluid and fluid throughout the mastoid air cells.
CONCLUSION:
Three peripherally enhancing lesions in the left frontal lobe in clinical setting are worrisome for infection with secondary abscess formation.
Left-sided craniotomy noted. There are three peripherally enhancing lesions in the left frontal lobe, measuring 2.8 x 3.1 cm anterosuperiorly in the middle frontal gyrus, 2.7 x 2.7 cm posteriorly and 16 x 10 mm anteroinferiorly. These demonstrate central diffusion restriction. The lesions demonstrate peripheral T1 hyperintensity and T2 hypointensity associated with susceptibility artefact consistent with subacute hemorrhage. Left frontal leptomeningeal and pachymeningeal enhancement is demonstrated. Bifrontal subdural collections measuring 6 mm on the right and 8 mm on the left and right parafalcine subdural collection measuring 4 mm do not demonstrate complete FLAIR suppression, however there is no enhancement or diffusion restriction to suggest empyaema.
There is extensive surrounding FLAIR hyperintensity in the left frontal lobe extending into the parietal lobe and mass effect characterized by sulcal effacement, partial effacement of the left lateral ventricle and rightward midline shift of 4 mm. The ventricles are stable in size. Cavum septum pellucidum et vergae incidentally noted.
Evidence of sinusitis involving the maxillary and sphenoid sinuses and is more air cells.
Conclusion:
Appearances are worrisome for abscess formation in the regions of prior hemorrhagic contusions in the left frontal lobe, associated with considerable edema and mass effect. Left frontal leptomeningeal enhancement suggests meningitis.
Case Discussion
The patient went on to have a craniotomy and drainage. At operation there was not a great deal of inflammation. The fluid form the collections was not frankly purulent.
Microscopy
- GRAM STAIN
- Leukocytes + (minima)
- No organisms seen
- CULTURE
- No growth after 5 days.
- ACTINOMYCES CULTURE
- No growth after 2 days
Histology
Organizing clot, no tumor, no organisms seen.
This case shows the difficulty in interpreting diffusion weighted imaging in the setting of blood. The presence of increasing edema, and pronounced diffusion restriction in a patient with fluctuating concious state should be considered suspicious for secondary infection of the contusions.
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