**3.1.2 Clinical presentation**

The ophthalmic presentation of CVT can be quite variable and it may have an acute or chronic onset. The most common ocular feature is papilloedema due to raised intracranial pressure. Acute papilloedema appears as flame shaped haemorrhages and cotton wool spots, which are an indication of nerve fibre layer infarction (Figure 6); whereas chronic papilloedema may have a 'champagne cork' like appearance (Figure 7). Despite the presence of papilloedema, visual acuity is often initially unaffected and the first ocular symptom to occur is usually visual field constriction (Figure 7). Patients can also present with visual obscuration with bending or coughing; and there may be diplopia due to cranial nerve VI palsy (Figure 8).

In cases of cavernous sinus thrombosis, ocular features are the predominant feature and can include ocular pain, chemosis, proptosis and cranial nerve palsies affecting the extraocular muscles. This is due to the close association between the oculomotor (cranial nerve III), trochlear (cranial nerve IV) and abducens (cranial nerve VI) nerve and the cavernous sinus.

Fig. 6. Fundus photograph showing acute papilloedema with haemorrhages (H) and cotton wool spots (C) in the right eye (a) and the left eye (b) of the same patient.

The ophthalmic presentation of CVT can be quite variable and it may have an acute or chronic onset. The most common ocular feature is papilloedema due to raised intracranial pressure. Acute papilloedema appears as flame shaped haemorrhages and cotton wool spots, which are an indication of nerve fibre layer infarction (Figure 6); whereas chronic papilloedema may have a 'champagne cork' like appearance (Figure 7). Despite the presence of papilloedema, visual acuity is often initially unaffected and the first ocular symptom to occur is usually visual field constriction (Figure 7). Patients can also present with visual obscuration with bending or coughing; and there may be diplopia due to cranial nerve VI

In cases of cavernous sinus thrombosis, ocular features are the predominant feature and can include ocular pain, chemosis, proptosis and cranial nerve palsies affecting the extraocular muscles. This is due to the close association between the oculomotor (cranial nerve III), trochlear (cranial nerve IV) and abducens (cranial nerve VI) nerve and the cavernous sinus.

Fig. 6. Fundus photograph showing acute papilloedema with haemorrhages (H) and cotton

wool spots (C) in the right eye (a) and the left eye (b) of the same patient.

**3.1.2 Clinical presentation** 

palsy (Figure 8).

Fig. 7. Fundus photograph showing a 'champagne cork' like appearance in chronic papilloedema in the right eye (a) and left eye (b) of the same patient. In the right eye, there is a Y shaped retinochoroidal shunt (S) due to the retinal vessels diverting towards the choroidal vessels and is another fundus feature of chronic papilloedema. Corresponding visual fields images shows significant field constriction in the right eye (c) and an enlarged blind spot in the left eye (d).

Venous Thrombosis and the Eye 171

Although controversial, failure in improvement with anticoagulation may require the use of direct endovascular thrombolysis (Einhaupl, Stam et al. 2010) which involves either mechanically (Scarrow, Williams et al. 1999) or chemically (Wasay, Bakshi et al. 2001) dissolving the clot. This is generally reserved for patients with poorer prognoses (Stam 2005), as there is the potential that thrombolysis may cause death or dependency in up to 40% of patients with CVT (Stam, Majoie et al. 2008). However, in critically ill patients, thrombolysis may reduce death compared to other treatments or no treatment at all

Aside from treatment of the CVT, it is important to manage any associated symptoms. In particular, control of elevated intracranial pressure is vital in patients with headaches, as well as preserving visual function. In cases of decreasing visual acuity associated with CVT, optic nerve sheath fenestrations may help to reduce pressure, thereby preventing optic

The prognosis of CVT is generally good. At 16 months, approximately 57% of patients with CVT have no signs or symptoms, and a further 22% of patients with CVT have only minor residual symptoms (Ferro, Canhao et al. 2004). Characteristics that are associated with a poorer prognosis include age over 37, male , previously having a coma or mental status abnormality; haemorrhage noted on imaging; deep venous system thrombosis; central nervous system infection and CVT associated with malignancy (Ferro, Canhao et al. 2004). Approximately 3% of patients die in the acute phase of CVT and 8% of patients die within the first 30 days following initial symptoms of CVT (Canhao, Ferro et al. 2005). Death is often due to transtentorial herniation or due to diffuse oedema and multiple parenchymal

Significant visual loss in CVT is rare (Purvin, Trobe et al. 1995), and if present, is often associated with prolonged elevated intracranial pressure. Visual prognosis depends upon

There is often recanalisation after CVT and this commonly occurs within the first four months. The likelihood of recanalisation occurring depends on the location of the CVT (Baumgartner, Studer et al. 2003). Following a CVT, approximately 3% develop a recurrent CVT and 6% develop another form of venous thromboembolism at 6 years (Martinelli,

Antiphospholipid syndrome (APS) is an autoimmune disease associated with both arterial and venous thrombosis. It is characterised by lupus anticoagulant, anticardiolipin antibody

The prevalence of ocular involvement in APS is variable, with studies suggesting that ocular

Ocular manifestations of APS include occlusive vascular disease (Miserocchi, Baltatzis et al. 2001; Suvajac, Stojanovich et al. 2007), vasculitis (Miserocchi, Baltatzis et al. 2001) and neuro-

nerve atrophy. Equally important in CVT treatment is the control of seizures.

(Canhao, Falcao et al. 2003).

lesions (Canhao, Ferro et al. 2005).

Bucciarelli et al. 2010).

**3.2.1 Prevalence** 

**3.2.2 Clinical presentation** 

the duration and severity of elevation in pressure.

**3.2 Ophthalmic manifestations of antiphospholipid syndrome** 

and anti-β2 glycoprotein-I antibody (Miyakis, Lockshin et al. 2006).

features can occur in 8% to 88% of patients with APS (Utz and Tang 2011).

**3.1.5 Prognosis** 

Fig. 8. Clinical photograph of all nine positions of gaze in a patient with a cranial nerve VI palsy associated with raised intracranial pressure. The patient complains of diplopia and there is weakness in the lateral rectus as indicated by the visibility of the sclera on lateral gaze (arrows).

#### **3.1.3 Investigations**

Magnetic resonance imaging (MRI) with magnetic resonance venography is the most sensitive method for diagnosing CVT and visualising brain parenchymal lesions. However, this sensitivity depends upon the location of the thrombosis (Ferro, Morgado et al. 2007).

Given its wide availability, computed tomography (CT) is often used for investigation of CVT. The radiological findings of CVT on CT are often non-specific and the scan may be normal in 30% of cases with CVT. Signs that assist in the diagnosis of CVT include the dense triangle sign on non-contrast CT (hyperdensity in the posterior part of the superior sagittal sinus caused by venous thrombosis), the cord sign on contrast CT (linear hyperdensity over cerebral cortex caused by venous thrombosis) and the empty delta sign on contrast CT (area where there is absence of contrast enhancement in the posterior part of the superior sagittal sinus) (Boukobza, Crassard et al. 2007). These signs occur in one-third of patients with CVT.

Ocular assessment in patients with CVT should involve serial visual acuity, visual field measurements and imaging of the optic nerve head with stereophotographs or other imaging modalities such as OCT in order to monitor progression.

Once diagnosed, an investigation for the possible causes of CVT may be warranted. This involves blood tests to screen for thrombophilias, as well as a search for a malignancy.

#### **3.1.4 Treatment**

Treatment aims to recanalise the occlusion, prevent thrombus propagation, address the underlying cause, and then control the symptoms of the condition such as vision loss.

The most important principle of treatment of CVT is anticoagulation (Coutinho and Stam 2010) in patients who have no contraindications to anticoagulation. Treatment with either unfractionated heparin or low molecular weight heparin has been shown to reduce the risk of death and dependency (Stam, De Bruijn et al. 2002). Anticoagulation appears to be safe in CVT patients with intracranial haemorrhages (Einhaupl, Stam et al. 2010), as the haemorrhages in CVT are the result of venous occlusion.

Fig. 8. Clinical photograph of all nine positions of gaze in a patient with a cranial nerve VI palsy associated with raised intracranial pressure. The patient complains of diplopia and there is weakness in the lateral rectus as indicated by the visibility of the sclera on lateral

Magnetic resonance imaging (MRI) with magnetic resonance venography is the most sensitive method for diagnosing CVT and visualising brain parenchymal lesions. However, this sensitivity depends upon the location of the thrombosis (Ferro, Morgado et al. 2007). Given its wide availability, computed tomography (CT) is often used for investigation of CVT. The radiological findings of CVT on CT are often non-specific and the scan may be normal in 30% of cases with CVT. Signs that assist in the diagnosis of CVT include the dense triangle sign on non-contrast CT (hyperdensity in the posterior part of the superior sagittal sinus caused by venous thrombosis), the cord sign on contrast CT (linear hyperdensity over cerebral cortex caused by venous thrombosis) and the empty delta sign on contrast CT (area where there is absence of contrast enhancement in the posterior part of the superior sagittal sinus) (Boukobza, Crassard et al. 2007). These signs occur in one-third of patients with CVT. Ocular assessment in patients with CVT should involve serial visual acuity, visual field measurements and imaging of the optic nerve head with stereophotographs or other

Once diagnosed, an investigation for the possible causes of CVT may be warranted. This involves blood tests to screen for thrombophilias, as well as a search for a malignancy.

Treatment aims to recanalise the occlusion, prevent thrombus propagation, address the underlying cause, and then control the symptoms of the condition such as vision loss. The most important principle of treatment of CVT is anticoagulation (Coutinho and Stam 2010) in patients who have no contraindications to anticoagulation. Treatment with either unfractionated heparin or low molecular weight heparin has been shown to reduce the risk of death and dependency (Stam, De Bruijn et al. 2002). Anticoagulation appears to be safe in CVT patients with intracranial haemorrhages (Einhaupl, Stam et al. 2010), as the

imaging modalities such as OCT in order to monitor progression.

haemorrhages in CVT are the result of venous occlusion.

gaze (arrows).

**3.1.3 Investigations** 

**3.1.4 Treatment** 

Although controversial, failure in improvement with anticoagulation may require the use of direct endovascular thrombolysis (Einhaupl, Stam et al. 2010) which involves either mechanically (Scarrow, Williams et al. 1999) or chemically (Wasay, Bakshi et al. 2001) dissolving the clot. This is generally reserved for patients with poorer prognoses (Stam 2005), as there is the potential that thrombolysis may cause death or dependency in up to 40% of patients with CVT (Stam, Majoie et al. 2008). However, in critically ill patients, thrombolysis may reduce death compared to other treatments or no treatment at all (Canhao, Falcao et al. 2003).

Aside from treatment of the CVT, it is important to manage any associated symptoms. In particular, control of elevated intracranial pressure is vital in patients with headaches, as well as preserving visual function. In cases of decreasing visual acuity associated with CVT, optic nerve sheath fenestrations may help to reduce pressure, thereby preventing optic nerve atrophy. Equally important in CVT treatment is the control of seizures.
