Short lasting unilateral neuralgiform headache attacks with conjunctival injection and tearing (SUNCT)

SUNCT and
optic nerve hypoplasia. a Coronal T2 sequence and b coronal FLAIR sequence showing a small right pituitary cyst and normal septum pellucidum. c Coronal T1 sequence with gadolinium showing a normal pituitary gland and infundibulum. d Coronal orbital inversion recovery sequence showing left optic nerve hypoplasia
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Short lasting unilateral neuralgiform headache attacks can present with either conjunctival injection and tearing (SUNCT) or with cranial autonomic symptoms (SUNA) are rare headache syndromes that belong to a larger group of headaches known as trigeminal autonomic cephalgia and can present very similarly to trigeminal neuralgia.

Clinical presentation

The diagnosis is clinical and can only be made in individuals who have had numerous events and in whom no other causes are identified. The international headache society diagnostic criteria for SUNCT are as follows :

  • a minimum of 20 attacks fulfilling criteria 2 to 4
  • short-lasting unilateral orbital, supraorbital, or temporal stabbing or pulsating pain (5 seconds to 4 minutes)
  • accompanied by ipsilateral conjunctival injection and tearing
  • frequent (3 to 200 attacks per day)
  • no other disorder accounts for symptoms

    • Radiographic features

    MRI

    Features of SUNCT and SUNA are similar to trigeminal neuralgia with vascular impingement fairly frequently encountered. This is an important finding as it can affect management decisions (e.g. surgical microvascular decompression ) but required dedicated imaging with high-resolution sequences and MRA (see trigeminal neuralgia protocol).

    Treatment and prognosis

    Treatment is challenging and many treatments have been tried, none of which have uniformly high success rates . These include medical (e.g. carbamazepine, gabapentin etc...), percutaneous (e.g. greater occipital nerve block) and surgical (e.g. trigeminal microvascular decompression) .

    Differential diagnosis

    The main differential diagnosis is of trigeminal neuralgia that can have very similar clinical and imaging features. The main clinical distinguishing feature is the absence of autonomic features in trigeminal neuralgia.