Intended for healthcare professionals

Endgames Case Review

Sudden onset headache in a 50 year old woman

BMJ 2017; 358 doi: (Published 21 September 2017) Cite this as: BMJ 2017;358:j4016
  1. Divyansh Gulati, specialty registrar in emergency medicine,
  2. Michael William Shea, senior house officer in obstetrics and gynaecology,
  3. James Ray, consultant in emergency medicine
  1. Emergency department, John Radcliffe Hospital, Oxford, UK
  1. Correspondence to M Shea m_w_shea{at}

A 50 year old woman presented to the emergency department several hours after the sudden onset of a severe headache with associated neck stiffness, photophobia, and vomiting. She reported having a dental abscess, and was taking norethisterone regularly for persistent vaginal bleeding. She had a 50 pack year smoking history. She was afebrile, alert (Glasgow coma scale 15), and had no focal neurological signs. Blood tests were unremarkable, in particular her white blood cell and neutrophil counts were within the normal range. A non-contrast computed tomography (CT) scan of the head was obtained in the emergency department (fig 1).

Fig 1
Fig 1

Non-contrast computed tomography (CT) scan of the head: (A) axial and (B) sagittal views


  • 1. What is the diagnosis based on the history and CT scan?

  • 2. What are the risk factors for this condition?

  • 3. What is the treatment for this condition?


1. What is the diagnosis based on the history and CT scan?

Short answer

Cerebral venous thrombosis, seen by the “dense triangle sign,” a hyperdensity at the posterior part of the superior sagittal sinus (fig 2a), and the “cord sign” (fig 2b), a homogenous hyperdensity that fills a sinus. Diagnosis is usually made from magnetic resonance (MR) or CT venography.

Fig 2
Fig 2

Non-contrast CT scan of the head showing thrombus in the cerebral sinus system. (A) Arrow points to the thrombus (seen as the dense triangle sign) on axial view. (B) Arrows point to the thrombus (seen most obviously as the cord sign in the superior sagittal sinus) on the sagittal view


The CT scan of the head shows expansion and increased attenuation within the superior sagittal sinus, right sigmoid sinus, and posterior part of the inferior sagittal sinus, in keeping with extensive cerebral venous sinus thrombus. As well as the “dense triangle sign” and “cord sign,” if contrast is used then the “empty delta sign” can be detected in some cases (where contrast surrounds an unenhancing clot in a dural venous sinus). Cerebral venous thrombosis can be diagnosed from an unenhanced CT scan in approximately 30% of cases.1 Where unenhanced CT imaging is equivocal, CT venography or MR venography can provide superior sensitivity and specificity in the detection of cerebral venous thrombosis. While MR venography is more sensitive in the detection of early parenchymal infarction associated with thrombosis, CT venography is faster, more cost effective, and is equivalent to MR imaging with respect to detection of thrombosis.1 Cerebral venous thrombosis is an uncommon condition in adults (incidence is approximately 1.5 per 100 000 per year) but is part of the differential diagnosis for a “thunderclap headache,” a severe, sudden onset headache typically described as the worst headache of the patient’s life, and which reaches maximal intensity within minutes.2 The presentation of cerebral venous thrombosis varies from a gradual onset headache (typically) to a sudden onset severe headache (in 10% of cases).3 The headache often has features typical of raised intracranial pressure, worse with lying flat or with Valsalva manoeuvres and associated with nausea. Associated signs and symptoms include focal neurological signs such as weakness, seizures, and in severe cases coma and death.4 Differential considerations for a hyperdense dural venous sinus or vein include cerebral venous thrombosis, polycythemia, hemoconcentration, or it can be a normal variant if the density of the sinus is below 70 Hounsfield Units.5

2. What are the risk factors for this condition?

Short answer

The main risk factors are hypercoagulable states (eg, protein C, protein S, anti-thrombin deficiency, Factor V Leiden, Prothrombin G20210A mutation, antiphospholipid syndrome), oral contraceptive pill, pregnancy/puerperium, cancer, infectious/inflammatory conditions, intracranial injury, and neonatal dehydration.


Most adult patients with cerebral venous thrombosis have at least one risk factor identified. The most common are genetic or acquired hypercoagulable states. In the International Study of Cerebral Vein and Dural Sinus Thrombosis, around one third of patients had a hypercoagulable condition (and two thirds of these were genetic).4 Patients with a high risk genetic predisposition (protein C deficiency, protein S deficiency, antithrombin deficiency, homozygous factor V Leiden, homozygous prothrombin G20210A mutation, or antiphospholipid syndrome) are also at higher risk of recurrence. Women are three times more likely than men to have a cerebral venous thrombosis because of the increased risk from oral contraceptive pill use and from the prothrombotic states of pregnancy and the puerperium. The average age for presentation in adults is 39.2 The condition is more common in children (particularly neonates) than in adults. In neonates, cerebral venous thrombosis is associated with perinatal complications and with dehydration.6

3. What is the treatment for this condition?

Short answer

Anticoagulation with heparin (unfractionated or low molecular weight heparin) in the short term, followed by warfarin. Management of complications, for example anticonvulsants for seizures, and treatment of raised intracranial pressure.


The aim of treatment is to prevent propagation of the thrombus, to aid recanalisation of the thrombosed vessel or sinus, and to manage complications such as raised intracranial pressure or seizures. The main treatment is anticoagulation, initially with heparin (unfractionated or preferably low molecular weight in a stable patient), followed by warfarin for three to six months for a provoked cerebral venous thrombosis, six to 12 months for an unprovoked event, and potentially lifelong treatment for patients with a high risk prothrombotic condition. Anticoagulation is generally recommended even in the presence of haemorrhagic lesions secondary to the cerebral venous thrombosis. Routine use of anti-convulsants is not recommended unless the patient has supratentorial lesions on brain imaging and has had one or more seizures. Management of raised intracranial pressure is as usual, with head-up nursing, intensive care input, use of mannitol or acetazolamide if required, and neurosurgical input for monitoring of intracranial pressure, and possibly ventriculoperitoneal drain insertion. Endovascular treatments (thrombolysis or thrombectomy) are occasionally used for severe cerebral venous thrombosis.3

Patient outcome

The patient was started on low molecular weight heparin and transitioned to warfarin. She made a good recovery and was discharged from hospital two days later. She is currently being followed up by the haematology team to investigate underlying prothrombotic conditions.


  • We have read and understood BMJ policy on declaration of interests and declare the no competing interests.

  • Patient consent obtained.

  • Provenance and peer review: not commissioned, externally peer reviewed.


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