Posterior fossa subdural hematomas may be spontaneous, with no previous trauma. These cases are usually secondary to bleeding from an underlying pathology such as arteriovenous malformation (AVM), aneurysm 1), tumor or coagulation disorders 2) 3).
see also Spontaneous retroclival subdural hematoma.
Posterior fossa craniectomy may be preferable in terms of diagnosis and safe treatment 4).
Hematoma evacuation is indicated as soon as possible, in order to minimize neurological deficits and to seek a satisfactory neurologic and clinical outcome 5).
Prognosis seems to be related to the clinical condition of the patient at the moment of surgery, according to the GCS. Patients with mild symptomatology usually have a good outcome, whereas, in most cases, there is no improvement if a moderate or severe neurologic deficit has already been established 6) 7).
Finger et al., from the Neurosurgery Department of Cristo Redentor Hospital, Porto Alegre, Brazil, report a case of spontaneous posterior fossa subdural hematoma treated with anticoagulant therapy that made good recovery after surgical treatment 8).
A 69-year-old woman was admitted with nausea, headache, and mild consciousness disturbance. Computed tomography and magnetic resonance imaging showed bilateral pCSH. To prevent further neurological deterioration, we performed surgery under general anesthesia by midline suboccipital craniectomy. Unexpected bleeding from a developed circuitous occipital sinus was stopped with hemoclips. After hematoma removal, she recovered and was transferred to a rehabilitation hospital. By the 19(th) postoperative day, she had developed no neurologic deficits.
This experience demonstrates the risk of blind surgical therapy in patients with pCSH. In such patients, posterior fossa craniectomy may be preferable in terms of diagnosis and safe treatment 9).
A 83-year-old woman was admitted with recent sudden headache and dizziness. Magnetic resonance imaging showed a thin collection of blood in the subdural space adjacent to the clivus, along the wall of the posterior fossa, and at the cervical spine level. A right posterior communicating artery aneurysm was diagnosed using computed tomography angiography and digital subtraction angiography. The aneurysm had two lobes, one of which was attached to the right dorsum sellae. The aneurysm was occluded by stent-assisted coil embolization. The patient was discharged 3 weeks after admission with absence of neurological deficit.
A ruptured aneurysm of the posterior communicating artery may cause an acute SDH 10).
A rare case of concomitant cranial and spinal subdural haematoma (SDH) in a 12-year-old boy with severe thrombocytopenia due to aplastic anaemia, and review the available literature. Magnetic resonance (MR) imaging at presentation revealed a cranial SDH confined to the posterior fossa, and spinal SDH extending from the C1 to S3 segments. The child was managed conservatively due to his poor general condition and lack of any neurological deficit. Repeat MR imaging done at six weeks showed complete resolution of the spinal SDH and partial resolution of the cranial SDH. Although rare, a spontaneous spinal SDH can occur simultaneously with a cranial SDH. Urgent surgical decompression is considered the treatment of choice for spinal SDH; however, a conservative approach may succeed in patients with poor general condition, and/or mild/no neurological deficit 11).
Berhouma M, Houissa S, Jemel H, Khaldi M. Spontaneous chronic subdural hematoma of the posterior fossa. J Neuroradiol. 2007 Jul;34(3):213-5. PubMed PMID: 17572494 12).
Usul et al., present a spontaneous posterior fossa subdural hematoma in a term neonate and discuss conservative management 13).
A case of spontaneous acute subdural haematoma in the posterior fossa following anticoagulation 14).
The association of the posterior fossa chronic subdural hematoma with spontaneous parenchymal hemorrhage without anticoagulation therapy was never related in the literature. Costa et al., describe a case of a 64 year-old woman who suffered a spontaneous cerebellar hemorrhage, treated conservatively, and presented 1 month later with a chronic subdural posterior fossa hematoma 15).
Miranda et al., present a case of a posterior fossa acute subdural hematoma occurring in an anticoagulated patient who was preoperatively misdiagnosed as an intracerebellar hemorrhage 16).
A 52-year-old woman treated for acute myeloproliferative disease developed progressive stupor. CT showed obstructive hydrocephalus resulting from unexplained mass effect on the fourth ventricle. MRI revealed bilateral extra-axial collections in the posterior cranial fossa, giving high signal on T1- and T2-weighted images, suggesting subacute subdural haematomas. Subdural haematomas can be suspected on CT when there is unexplained mass effect. MRI may be essential to confirm the diagnosis and plan appropriate treatment 17).
A 70 year old female presented with progressive dizziness, vertigo and gait ataxia. She was on anticoagulation therapy for heart disease. Neuro-imaging revealed bilateral infratentorial subdural masses. The subdural masses were suspects for chronic subdural haematomas by neuroradiological criteria. Because of the progressive symptomatology, the haematomas were emptied through burrhole trepanations. Chocolate-colored fluid, not containing clotted components, gushed out under great pressure. The source of bleeding could not be identified. The patient recovered well from surgery, but died 4 months later shortly after admission to another hospital from heart failure.
The chronic subdural haematomas in this patient may have been due to rupture of bridging veins caused by a very mild trauma not noticed by the patient and possibly aggravated by the anticoagulation therapy. Infratentorial chronic subdural haematoma should at least be a part of the differential diagnosis in elderly patients with cerebellar and vestibular symptomatology even without a history of trauma 18).
A case of spontaneous acute subdural hematoma complicated with idiopathic thrombocytopenic purpura was reported. He was hospitalized complaining of sudden onset of headache and nasal bleeding without neurological deficit. CT scan revealed subdural hematoma in the posterior fossa especially below the tentorium cerebelli. Further hematological examination proved very low platelet count (1,000/mm3) and antiplatelet antibody in confirmation of a diagnosis of idiopathic thrombocytopenic purpura. As his neurological status was good, he was treated medically. His symptoms and platelet count improved gradually with corticosteroid therapy. Reviewing the literature, acute subdural hematoma with idiopathic thrombocytopenic purpura was quite rare and only three cases reported 19).
Aicher KP, Heiss E, Gawlowski J. [Spontaneous subdural hematoma in the posterior cranial fossa]. Rofo. 1988 Dec;149(6):669-70. German. PubMed PMID: 2849170 20).
Kanter et al., report a patient in whom a spontaneous subdural hematoma developed in the posterior fossa during anticoagulation therapy for mitral valve disease. This rare complication of anticoagulation has been reported in only three other patients 21).
A case of spontaneous posterior fossa subdural hematoma secondary to anticoagulation therapy with definitive diagnosis made by vertebral angiography is reported. Vertebral angiographic findings are illustrated and demonstrate primarily mass effect from posterior compartment of posterior fossa and avascular area. Carotid angiography did not show hydrocephalus. A review of the literature was made and this appears to be the first reported case in which a posterior fossa subdural hematoma has been diagnosed by vertebral angiography 22).
A report of spontaneous posterior fossa subdural haematoma associated with anticoagulation therapy. The possibility of posterior fossa lesions related to spontaneous haemorrhage is suggested by the combination of severe headache and increasing disturbance of consciousness associated with signs of brain-stem decompensation. A thorough neurological evaluation including appropriate contrast studies will help rule out a supratentorial lesion. This is a neurological emergency which can be successfully treated by early detection and prompt surgical decompression. This is the second reported case of spontaneous subdural haematoma of the posterior fossa occurring during anticoagulant therapy 23).