In 1850, Tellegen appears to have been the first to describe the clinical symptoms of spinal cord hematoma or hematomyelia. The symptoms have not changed significantly with the passage of time and the few that have occurred, change only slightly with varying etiologies.
Spinal cord hematoma or hematomyelia is an infrequently encountered condition that is the result of several unusual disease processes. The causes of spontaneous, nontraumatic spinal cord hematoma include vascular malformations of the spinal cord (the most common), clotting disorders, inflammatory myelitis, spinal cord tumors, abscess, syringomyelia, and unknown etiologies. Traumatic events, such as spinal cord injury (closed or penetrating), and operative procedures involving the spinal cord also can cause a spinal cord hematoma. In addition, several instances of intramedullary spinal cord hematomas have been reported following lumbar or C1-C2 punctures. [1, 2, 3, 4, 5]
Because of the rarity of hematomyelia, its numerous etiologies, and its varied clinical presentations, this article provides a general overview of spinal cord hematomas and briefly discusses each etiology separately. Because hematomyelia is a rare entity, treatment and outcomes, regardless of the cause, are based primarily upon anecdotal evidence and the treating surgeon's philosophy.
Since the original publication of this article, several other case reports have been published that discuss intramedullary spinal cord hematomas. These case reports, while detailing several unusual presentations of patients with intramedullary spinal cord hematomas, add little to the core concepts described in the original article. Patients suffering from intramedullary spinal cord hematomas present with severe spinal pain and significant neurological findings related to the level of spinal cord involvement; MRI with and without gadolinium is still the procedure of choice for early diagnosis; and successful outcomes depend on early diagnosis, aggressive, emergent surgical treatment and drainage of the hematoma. Even when these guidelines are followed, outcome following surgery is highly correlated with the initial neurological status of the patient.
The epidemiology of hematomyelia is based directly upon the underlying pathological process. No general statements can be made with regard to age, incidence, gender, or specificity of symptoms because these depend upon the underlying pathology.
Hematomyelia associated with vascular malformations
Neurological deficits are related to the location of the malformation and occur emergently, with no change over time. Diagnosis and treatment follow those of any spinal cord AVM—a subject too broad for this article.
Hematomyelia associated with coagulopathies
Both congenital coagulopathies, such as hemophilia and factor XI deficiency, and drug-induced coagulopathies, primarily from Coumadin, have been associated with hematomyelia.
Schenk  and Wisoff,  in separate reports, detail cases in which patients suffered a spinal cord hematoma secondary to their intrinsic coagulopathies. One case, a cervical clot, was the result of hemophilia, and the other, also a cervical clot, was secondary to factor XI deficiency. Both patients underwent surgery with minimal improvement of their neurological deficits.
Other reports detail intramedullary clots following treatment with Coumadin (warfarin).  In these patients, treatment was not only surgical but also involved the correction of the coagulopathy by reversing the effects of Coumadin.
Hematomyelia associated with myelitis/vasculitis
Evacuation of the patient's thoracic clot provided some improvement in function.
Hematomyelia associated with intramedullary tumors (See the image below.)
Surprisingly, hemorrhage into a spinal cord tumor is a rare event. Cauda equina tumors bleed fairly frequently but usually only produce subarachnoid blood.
Tumors most commonly associated with an intramedullary hematoma include ependymomas, hemangioblastomas, cavernous angiomas, schwannomas, and astrocytomas. Treatment consists of both tumor and clot removal. Outcome is determined primarily by the tumor pathology.
Hematomyelia associated with syringomyelia
Bleeding into a syrinx is a well-recognized phenomenon that Gowers first described in 1886.  Since then, several cases of hematomyelia in a syrinx have been reported.
Clinical presentation is usually that of a sudden exacerbation of the symptoms of the syrinx itself, other symptomatology includes an acute worsening of symptoms that subsequently improves or a gradual deterioration of function. Most cases of intrasyringal hemorrhage are associated with either scoliosis or a Chiari I malformation. Some authors believe that the hemorrhage is caused by abnormal blood vessels lining the walls of the cyst cavity, and others believe that an acute dilatation of the syrinx tears existing vessels lining the cavity. Treatment is drainage of the clot and drainage of the syrinx. Most patients improve after surgery.
Hematomyelia of unknown etiology
Several cases of spinal cord hematoma appear to have no underlying cause or pathology.
Both Brandt  and Leech  reported such cases. Even at autopsy, no underlying cause could be identified. Their patients underwent surgical removal of the clot, but no significant improvement in function was noted.
Regardless of the cause, the almost universal initial symptom of spinal cord hematoma is sudden onset of excruciating back or neck pain. The location of this pain relates directly to the location of the underlying pathology and hematoma.
The neurological deficit caused by the hematoma also directly correlates with the region of hemorrhage. Neurological deficits vary somewhat with the underlying etiology. The deficit associated with a vascular malformation occurs suddenly, along with the pain, and does not usually increase substantially over time. The deficits associated with hematomas from other etiologies may lag the initial onset of pain by several hours. The deficit also may evolve over a period of 2-24 hours, or it may even take days.