Posterior fossa hematomas are life-threatening hemorrhages that affect the structures of the posterior fossa (cerebellum and the brainstem) and can cause coma and death in severe cases. While there are many causes of nontraumatic posterior fossa hemorrhages, primary hypertensive hemorrhages, ruptured aneurysms / vascular malformation, and hemorrhage associated with anticoagulation or thrombolytics make up the majority.

Symptoms from a posterior fossa hemorrhage are typically acute in onset and can include severe headache, vomiting, decreased level of consciousness, hemiplegia, vertigo, ataxia, and gait abnormalities. In severe cases, patients can present with coma.

Etiologies of posterior fossa hemorrhages include the following:

• Primary hypertensive intracerebral hemorrhage – History, vitals, and CT head without contrast showing a hemorrhage in a location typical of primary hypertensive hemorrhages should make this diagnosis.
• Ruptured aneurysm – CT angiogram may be diagnostic, but if suspicion is high enough for an aneurysm, a conventional angiogram would be the test of choice.
• Ruptured arteriovenous malformation less often can have venous or dural vascular malformations – Conventional angiogram.
• Hemorrhage into primary and secondary brain tumors – MRI with contrast.
• Venous sinus thrombosis
• Trauma – History and a CT head without contrast should be sufficient to make this diagnosis.
• Septic or mycotic aneurysm
• Hemorrhagic conversion into an ischemic stroke
• Hemorrhagic disorders such as leukemia, aplastic anemia, thrombocytopenic purpura, severe liver disease, complications of anticoagulation therapy or thrombolytic therapy, hypofibrinogenemia, hemophilia, and other hematologic disorders
• Illicit drugs (eg, cocaine)