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A rare complication of dental abscesses
  1. A Doss,
  2. P N Taylor,
  3. P F Down
  1. Department of Medicine, Dorset County Hospital, Dorchester, Dorset, UK
  1. A Doss, Department of Diagnostic Radiology, Royal Hallamshire Hospital, Sheffield, UK

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A 27-year-old cannabis smoker was admitted with a 3-week history of gradually worsening occipital headache. He had been pyrexial one week earlier, and had been put on an oral course of amoxycillin by his general practitioner. He had a history of recurrent dental abscesses and childhood asthma. He was not an intravenous drug abuser.

On examination he was well with a temperature 37.5°C, pulse rate 80 beats/min, blood pressure 130/80 mmHg. He had bilateral papilloedema, sustained ankle clonus, and brisk knee and ankle jerks. Examination was otherwise unremarkable. Full blood count, apart from a mean corpuscular volume of 101 fl, was normal. Liver function tests, urea, electrolytes, clotting, thrombophilia screen, auto-immune profile, erythrocyte sedimentation rate, serum electrophoresis and blood cultures were unremarkable. Visual field testing showed slightly enlarged blind spots in both eyes. An urgent brain computed tomography (CT) scan was performed within (figure 1).

Figure 1

Cranial contrast-enhanced CT

Two days following admission he developed pain and swelling of the right lower jaw and was referred to the maxillofacial surgeons who diagnosed dental abscesses. He went on to have incision and drainage of the lower right buccal space and multiple dental extractions under general anaesthesia. He was treated with antibiotics for 2 weeks and discharged home after making a full recovery. He is currently under follow-up with monthly visual field testing and regular dental review.

Questions

1
What does figure 1 show? What is this sign called?
2
What is the investigation shown in figure 2? What does it show?
3
Is there an association between the CT findings and the dental abscesses?
4
Are anticoagulants routinely indicated in this condition?

Answers

QUESTION 1

There is a filling defect in the superior sagittal sinus in keeping with superior sagittal sinus thrombosis (figure 1). This appearance is known as the ‘delta sign’. On an enhanced brain CT scan,the normal sagittal sinus is homogenously opaque.Thrombus within the lumen of the sinus appears as a filling defect outlined by contrast, often triangular or delta-shaped, which is known as the delta sign.

QUESTION 2

Figure 2 is a phase-contrast magnetic resonance angiography (MRA) sequence coded for venous flow. This confirms occlusion of the superior sagittal sinus.

QUESTION 3

It is possible that dental abscesses played a causative role in the sagittal sinus thrombosis of our patient. Septic intracranial sinus thrombosis as a complication of upper respiratory tract infections is well recognised.

QUESTION 4

Anticoagulation is not routine in sagittal sinus thrombosis. Management relies on treating the underlying cause and raised intracranial pressure rapidly and effectively.

Discussion

As far as we know this is the first case report of septic sagittal sinus thrombosis associated with dental abscesses. Sepsis is a predisposing factor, most frequently bacterial meningitis or facial sinus infection.1 Other reported associations include primary thrombocythaemia, homocystinuria, intracranial angiography, dehydration, Behcet's disease, haemolytic anaemia, coagulopathies, inhalational drug abuse, the post-partum period and the oral contraceptive pill.2 The natural history of this condition is highly variable with mortality ranging between 10–20%.

At present, venous MRA is probably the definitive examination and the gold standard for diagnosis of dural sinus thrombosis.3However, brain CT, which is usually the initial examination, may be diagnostic by demonstrating the ‘delta sign’ in 70% of cases.4 CT or MRI may also identify areas of haemorrhage or venous infarction in the adjacent brain.

The management of intracranial dural sinus thrombosis is still controversial and uncertain. There are no controlled trials of therapy. However, it is important to treat the underlying cause and raised intracranial pressure. Anticoagulants may be indicated early when there is no radiological evidence of haemorrhage.2 3 More recently, direct thrombolysis of dural sinus thrombosis has shown a better outcome in these patients.5 6

The decision regarding anticoagulation should be based on the severity of acute presentation, underlying associated conditions, evidence of haemorrhage or venous infarction of adjacent brain tissue on CT or MRI, and advice from neurologists and neurosurgeons should be sought sooner rather than later.

Sagittal sinus thrombosis

  • septic complication of bacterial meningitis, facial sinus infection, dental abscess

  • 10–20% mortality, worse in sepsis

  • diagnosis: cranial CT with contrast (‘delta sign’); MRA is the definitive investigation

  • treatment is of underlying condition and raised intracranial pressure; anticoagulation is controversial; direct thrombolysis is increasingly used

  • other associations: post-partum, dehydration, marasmus, oral contraceptives, inhalational drug abuse, coagulopathies, haemolytic anaemia, primary thrombocythaemia, sickle cell anaemia, Behcet's disease, head injury, homocystinuria

Final diagnosis

Superior sagittal sinus thrombosis as a complication of dental abscesses.

References

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