Rapid, spontaneous disappearance of acute subdural hematoma

Surgical significance of prolonged fixed and dilated pupils in a case of non-traumatic, spontaneously regressing, acute subdural haemorrhage

Bilaterally fixed and dilated pupils (BFDP) in traumatic acute subdural haematoma (ASDH) patients represent an ominous sign that portends irreversible brainstem injury and death. Whether patients with spontaneous ASDH and BFDP follow similar outcomes is unknown. We present a mid-60s man, found unconscious, with a Glasgow Coma Scale (GCS) of 4 following 8 days of headaches. Emergency CT imaging demonstrated a large right ASDH and the patient exhibited BFDP for >3 hours despite sedation and mannitol. Neurological improvement and spontaneously reduced SDH thickness were observed 10 hours postadmission, and he was later transferred for craniotomy and ASDH evacuation. His long-term outcomes were good: achieving independence in his activities of daily living and a GCS of 15. To the best of our knowledge, this is the first reported patient with a spontaneous, regressing ASDH and prolonged BFDP who clinically improved. This case raises important questions regarding factors used to determine prognosis and surgical viability for ASDH.

Shedding new light on rapidly resolving traumatic acute subdural hematomas

BACKGROUND

Rapidly resolving acute subdural hematomas (RRASDHs) have been described in case reports and case series but are still poorly understood. We hypothesized that a cohort analysis would confirm previously reported predictors of RRASDH including coagulopathy, additional intracranial hemorrhage, and low-density band on imaging. We also hypothesized that rapid resolution would be associated with improved trauma outcomes.

METHODS

We reviewed all nonoperative acute subdural hematomas (ASDHs) treated at our center from 2011 to 2015. Inclusion criteria were ASDH on computed tomography (CT), admission Glasgow coma score >7, and repeat CT to evaluate ASDH change. RRASDH was defined as reduced hematoma thickness by 50% within 72 h. Clinical data, CT findings, and trauma end points were analyzed for the RRASDH and nonresolving groups.

RESULTS

There were 154 ASDH patients included, with 29 cases of RRASDH. The RRASDH group had a lower rate of comorbidities than the nonresolving group (58.6% versus 78.4%, P = 0.03) and a lower rate of prehospital anticoagulation (7.7% versus 37.1%, P = 0.004). Previously reported predictors of RRASDH did not differ between the groups, nor did any clinical outcome measures. When compared with patients who experienced rapid growth (>50% increased width in 72 h), the RRASDH group had lower mortality (3.4% versus 23.5%, P = 0.04).

CONCLUSIONS

To our knowledge, this is the largest review of RRASDHs. We identified two previously unrecognized factors that may predict resolution; however, previously reported predictors were not associated with resolution. We also found no relationship between RRASDHs and improved standard trauma outcomes, calling into question the clinical significance of RRASDH.

The clinical and CT features of rapid spontaneous resolution of traumatic acute subdural hematoma: A retrospective study of 14 cases

OBJECTIVE

Resolution of a traumatic acute subdural haematoma (ASDH) requires weeks or months. However, cases of rapid spontaneous resolution of ASDH within 72 hours after trauma have been reported. The purpose of this study was to obtain a better understanding of the clinical and CT features of cases of rapid resolution following traumatic ASDH.

METHOD

Between 2011-2014, the authors retrospectively collected data from 14 patients with rapid resolution of traumatic ASDH. The clinical data and CT findings of these cases were collected and analysed.

RESULTS

In 13 of the 14 patients, there was a rapid spontaneous resolution of the ASDH within 48 hours. The mean haematoma width of the second CT was significantly smaller than the width of the initial CT. A significantly marked resolution of the midline shift was observed in the second CT in all patients. The outcome was good in the majority of patients.

CONCLUSIONS

The acute fluctuation of ICP may drive the spontaneous rapid resolution and redistribution of ASDH. Patients with abnormal coagulant function may be more likely to experience rapid resolution of ASDH. A band of low density in the initial CT image may be a useful sign for rapid resolution of ASDH.

Fluctuation of intra-parenchymal cerebral pressure may drive the rapid spontaneous resolution of acute subdural hematoma

Acute subdural hematoma (ASDH) is a severe insult with a high mortality rate, and emergent surgical evacuation is recommended in the vast majority of such cases. Generally, resolution of the hemorrhage requires weeks and months in patients treated conservatively. However, numerous cases of rapid spontaneous resolution of ASDH, occurring within 72h after the trauma, have been reported to date in the literature. Several possible hypotheses have been suggested, primarily involving redistribution and dilution, or washing out the ASDH. In this study, we present the relevant images of such a case, review the mechanisms of the rapid spontaneous resolution in the literature, and also propose a new hypothesis to explain the occurrence of the rapid spontaneous resolution of ASDH. We indicate that the fluctuation of intra-parenchymal cerebral pressure that drives the rapid spontaneous resolution of ASDH.

[Spontaneous resolution of an acute subdural hematoma]

Acute postraumatic subdural hematoma is known to have bad prognosis. Traditionally, its treatment consisted in urgent surgical evacuation. Rapid spontaneous resolution of the hematoma has been infrequently observed. We report a case of a patient with an acute traumatic subdural hematoma which disappeared without surgery. CT-scan showed a left-sided subdural hematoma with marked mass effect. A low density layer, which implied involvement of CSF in the subdural space, was observed between the hematoma and the inner wall of the skull. We think that the spontaneous resolution of the hematoma was due to the dilution and washing-out by the CSF through an arachnoid tear. Another suggested mechanism in the literature is blood redistribution in the subdural space. Selected patients with an acute subdural hematoma can be managed with conservative treatment.

Origin of chronic subdural haematoma and relation to traumatic subdural lesions

The origin of chronic subdural haematoma (CSDH) and the pathogenesis of subdural hygroma (SDG) are still controversial issues. These issues and relationships between these traumatic subdural lesions are discussed. The origin of CSDH is usually a SDG, although a few cases are caused by acute subdural haematomas (ASDH). Subdural hygroma is produced by separation of the dura-arachnoid interface, when there is sufficient subdural space. When the brain remains shrunken, the SDG remains unresolved. Any pathologic condition inducing cleavage of tissue within the dural border layer at the dura-arachnoid interface can induce proliferation of dural border cells with production of neomembrane. In-growth of new vessels will follow, especially along the outer membrane, then bleeding from these vessels occurs. These unresolved SDGs become CSDHs by repeated microhaemorrhage from the neomembrane. Although most victims with ASDH underwent surgery or died, some patients could be managed conservatively. Since the ASDH is usually absorbed within a few weeks, only a very few ASDHs become CSDHs, when there is a sufficient potential subdural space. Chronic subdural haematoma can arise from ASDH, but more commonly from SDG. Such transformation, or development of a new subdural lesion, is a function of the premorbid status and the dynamics of absorption and expansion.