Working Diagnosis:
Left proximal and mid transverse sinus venous thrombosis (cerebral venous thrombosis).

Treatment:
The team neurosurgeon was consulted, and the American Heart Association/American Stroke Association’s recommended cerebral venous thrombosis lab evaluation for coagulopathy was performed to evaluate for an underlying cause of her thrombosis. The panel was within normal limits and revealed normal protein C, protein S, and antithrombin III activity, negative Factor V Leiden (F506Q) and Prothrombin Factor II (G20210A) gene mutations, negative Cardiolipin antibodies, normal Protein S Free Antigen and homocysteine levels, and negative Lupus Anticoagulant and dRVVT screens. A TSH and CBC were also within normal limits.
The neurosurgeon deduced that the patient had no risk factors for cerebral venous thrombosis other than dehydration; she had not increased her hydration as her training load increased during the summer months. She was started on a four-week course of daily ASA 81 and referred to vestibular therapy.

Outcome:
The patient's symptoms resolved over the course of two weeks. A four-week follow up MRA demonstrated resolution of the thrombus with a smaller but patent left transverse sinus. Case Photo #4 Following this normal study, she underwent a graduated return-to-play protocol without complication and has been asymptomatic since. Her coach and trainer have paid close attention to her hydration status and have monitored her for headaches. She played in all 14 games this season and has been asymptomatic. She has been advised not to start OCPs in the future.

Author's Comments:
Cerebral venous thrombosis (CVT) is a rare condition affecting approximately five people per million each year. It is defined by thrombosis of the cerebral veins or occlusion of the dural sinuses. Early changes include dilatation of the proximal cerebral veins and recruitment of collateral pathways, but increases in venous pressure may lead to disruption of the blood-brain barrier, vasogenic edema, and eventually parenchymal damage, cerebral edema and venous hemorrhage. The clinical presentation varies by location and extent of the thrombus and whether there is simply increased intracranial pressure or if the disease has progressed to involve the parenchyma. Symptoms and signs may include those of intracranial hypertension such as headache, vomiting, papilledema and visual disturbances, a focal syndrome such as a seizure or neurologic deficit, as encephalopathy, or a combination of the above. The most common presenting symptoms are a progressive, localized headache (though the characterization of the headache varies) or a seizure.
Risk factors for adolescents and adults include prothrombotic conditions (factor V leiden, deficiency of antithrombin III, protein S or protein C, antiphospholipid syndrome, hyperhomocysteinemia, etc), oral contraceptives, hormone replacement therapy, exogenous androgens, pregnancy, malignancy, infection (otic, systemic, or intracranial), head injuries, lumbar puncture, neurosurgery, ventricular catheterization, and dehydration. In a study of 624 cases of adult cerebral venous thrombosis, 75% were female and a gender specific risk factor (OCPs, pregnancy, or hormone replacement therapy) was identified in 65% of these patients. Prothrombotic conditions were identified in 34% of all patients. A majority of patients affected were under 50 years of age, with the mean female patient presenting at age 34 and male at 42.
The 2011 American Heart Association/American Stroke Association Proposed Algorithm for Management of CVT recommends evaluation with MRI T2-weighted imagine with venography when clinical suspicion of CVT is present. Once confirmed, anticoagulation is recommended. There are no published return-to-play guidelines for this condition. Once the athlete’s symptoms resolved and her four-week follow-up MR angiogram showed patency of the left transverse sinus, we used a standard concussion return-to-play protocol as a model to assure that her symptoms did not reproduce with activity. As intrinsic risk factors were ruled out, we do not anticipate a recurrence; the recurrence rate is 2-4% and is much more likely in those with risk factors and in men. To minimize this possibility, though, we have advised that she avoid OCPs in the future, to stay hydrated, and report headaches to her training staff.

Editor's Comments:
This case is an interesting twist on a common complaint that we see in sports medicine. Many patients present with multiple concussions, but concussion symptoms or headaches without recent trauma require additional investigation. This case also stresses the importance of thorough, and regular screening exams and the ability of these exams to find and treat significant medical conditions. As the author identifies this is a rare condition and the patient had few risk factors so a high index of suspicion was needed.

References:
Ferro JM, Canhão P. Etiology, clinical features, and diagnosis of cerebral venous thrombosis. In: UptoDate, Kasner SE (Ed), UpToDate, Waltham, MA (Accessed on 4/12/15).
Ferro JM, Canhão P, Stam J, et al. Prognosis of cerebral vein and dural sinus thrombosis: results of the International Study on Cerebral Vein and Dural Sinus Thrombosis (ISCVT). Stroke 2004; 35:664.
Ferro JM, Canhão P. Treatment and prognosis of cerebral venous thrombosis. In: UptoDate, Kasner SE (Ed), UpToDate, Waltham, MA (Accessed on 4/12/15).
Saposnik G, Barinagarrementeria F, Brown RD Jr, et al. Diagnosis and management of cerebral venous thrombosis: a statement for healthcare professionals from the American Heart Association/American Stroke Association. Stroke 2011; 42:1158.

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