Teaching Case

A 55-year-old man with sudden headache at the fourth day after surgery, performed to remove a meningioma in the right frontoparietal convexity. A new cranial CT examination was recommended for a better assessment.

Computed tomography shows surgical changes with right frontoparietal cranioplasty of titanium without associated local complications and without involvement of the brain parenchyma secondary to resection of supratentorial meningioma (Fig. 2).
Away from the surgical bed, CT also shows a right cerebellar hemisphere haemorrhage with mild mass effect and minimal adjacent oedema (Fig. 3); and a subarachnoid haemorrhage over the left cerebellar sulci, an image known as the “zebra sign” (Fig. 4).
The mentioned findings are consistent with the diagnosis of remote cerebellar haemorrhage.
The previous MRI study ruled out the presence of DAVF or cerebellar MAV and the linear morphology and distribution of the lesions did not correspond with a vascular territory, which discarded a cerebellar infarction with haemorrhagic transformation.

Remote cerebellar haemorrhage is a rare post-surgical complication (0.3 - 0.6% in supratentorial craniotomies and 0.08% in spinal surgery) [3, 6, 7, 8], resulting from a superficial haemorrhagic venous infarction in the territory of the superior cerebellar veins [5]. Its maximum incidence occurs in the immediate postoperative period (first 24 hours) [2, 6, 8]. It has 8.4% morbidity and 8% mortality [7, 8]. It occurs most often in the cerebellum, but may be also in the region of the thalami, midbrain or rostral region of the posteroinferior pons. Different hypotheses have been considered to try to explain the pathophysiology of this phenomenon. Currently the most widely accepted is the hypothesis proposed by Dr. Yoshida et al. They have postulated this to be due to a rapid loss of CSF, which causes cerebellar sagging, giving rise to a transient occlusion or tearing of the upper bridging veins in the posterior fossa, which leads to the venous congestion that causes the haematoma [1, 5, 6, 7, 8]. The most important predisposing factors are those related to the circulation of CSF (e.g. suction of the postoperative drainage, type of surgical approach, tearing of the dural sac in spinal surgery) and perioperative hypertension or use of hypotensive drugs during surgery [5, 6]. Other secondary factors are coagulopathy or preoperative use of antiplatelet agents [1, 2, 5, 6, 7]. There does not seem to be a correlation between the incidence and the type of lesion that makes the surgery necessary (tumour, aneurysm, surgery for the treatment of epilepsy...), the surgical position [4, 6] or patient‘s prior blood pressure [1]. Non-contrast CT is the test of choice to detect haemorrhagic lesions. The most common radiologic finding is the so-called “zebra sign”, a streaky curvilinear pattern area of increased attenuation in the cerebellar sulci, due to a subarachnoid haemorrhage caused by the rupture of bridging veins. We can also see a superficial linear parenchymal cerebellar haemorrhage in the hemispheres and/or vermis [2, 7, 8]. Cerebellar haemorrhage in the typical setting can be identified as RCH and does not require more extensive or invasive evaluation [1]. The clinical presentation varies from absence of symptoms (the most frequent) to seizure, a decreased level of consciousness, prolonged awakening from anaesthesia, dysarthria and other cerebellar symptoms [1, 8]. The treatment is conservative, since it is usually a self-limiting complication. Surgery is reserved for cases of obstructive hydrocephalus, decreased level of consciousness or cerebellar oedema [1, 8].