Abstract
SUNCT (short-lasting unilateral neuralgiform pain with conjunctival injection and tearing) belongs to a group of headache syndromes classified as trigeminal autonomic cephalalgias (TACs). Their common pathophysiological attribute is the involvement of the trigemino-autonomic reflex (1). Apart from SUNCT, paroxysmal hemicrania, cluster headache and cluster tic syndrome share the TACs’ typical clinical picture of severe unilateral pain following a trigeminal distribution with marked autonomic symptoms such as conjunctival injection, tearing and rhinorrhoea. The SUNCT syndrome is a rather rare condition. Since the first description by Sjaastad et al. in 1989 (2) some hundred cases of primary SUNCT syndrome might have been reported worldwide. In 1991, Bussone presented the first symptomatic case (3). Since then, some symptomatic cases, most of them associated with posterior fossa abnormalities (4, 5) and some cases of secondary SUNCT syndrome due to pituitary abnormalities have been reported (6, 7). Additionally, some cases of SUNCT syndome supposedly derived from trigeminal neuralgia (TN) (8) were described. The SUNCT syndrome shares the triggering factors, the orbital location and the recurrent crises of TN, thus, TN is the key differential diagnosis of SUNCT syndrome. Several cases of TN with marked autonomic features (9) have been published which raised the interesting question, if SUNCT and trigeminal neuralgia deserve distinct nosological categories or if SUNCT syndrome is a variation of TN. We describe a case of post-traumatic trigeminal affection with prominent autonomic symptoms suggesting a post-traumatic SUNCT syndrome.
Case report
A 20-year-old African male presented to our outpatient department 7 weeks after a traumatic head injury. During a fight he had experienced several blows of fists in the right orbital region and maxilla. After he was hit by a glass bottle on the back of his head he fell unconscious for less than one hour and was treated elsewhere. A maxillar fracture and a multifragmented nasal bone fracture was revealed on the initial CT. Right-sided unilateral headaches started on the day after the trauma: he suffered from frequent, stereotyped attacks of abrupt onset with intense right peri-orbital, stabbing or lancinating pain, lasting typically 20–60 s with a high frequency of up to 8 times per hour in a cluster like manner to a maximum of approximately 20 clusters per day. They were associated with marked tearing on the right side, ptosis, moderate reddening of the right eye, some nasal congestion (without rhinorrhoea) and a feeling of right sided forehead sweating. Attacks were often precipitated by touching the hair on the right scalp and touching the right forehead. He had tried paracetamol (acetaminophen) up to 2 g per day without effect. On the first consultation we could witness an attack and confirm the symptoms mentioned above. Though the attack was severe, the patient did not have to stop talking. A miosis in dim lighting could not be excluded under routine conditions due to the very dark irisis of our patient; when illuminated, both pupils were small. During the attack there was allodynia in the right V1 area. Between the attacks, the patient described hypesthesia in the same region. There was no phonophobia or photophobia, no scotoma and no nausea. The ptosis persisted outside the attack: on a follow-up appointment the patient indicated that this ptosis of unknown origin was known from his childhood. Nevertheless, the ptosis clearly increased during the attacks. Otherwise, the patient's history was unremarkable, there was no history of migraine and no family history of headache. Apart from the symptoms mentioned above, there were no neurological signs or deficits and blood pressure was normal.
Extracranial and transcranial Doppler ultrasonography (performed shortly after one attack) showed decreased mean velocities in the antero-medial cerebral circulation: 39 cm/s in the right internal carotid artery (ICA), the right medial cerebral artery (MCA) (mean velocity 46 cm/s) and the right anterior cerebral artery (ACA, mean velocity 65 cm/s) were measured compared to the left ICA (46 cm/s), the left MCA (71 cm/s) and the left ACA (65 cm/s). The posterior circulation showed symmetrical velocities. MRI (7 weeks after the head injury) of the brain revealed a small right frontal chronic subdural haematoma. There was no lesion in the posterior fossa and a carotid dissection could be excluded with the appropriate fat saturated sequences. Treatment with carbamazepine was initiated at a dose of 100 mg daily for two days. Due to fatigue it took several trials within the following 2 weeks to increase the dose, in the end 400 mg per day were tolerated. On the follow up, pain had stopped under this dosage during intake of 4 weeks and did not relapse after stopping the drug. A slight hypesthesia in right V1 persisted on clinical examination.
Discussion
This patient presented with frequent attacks of severe, short-lasting, unilateral neuralgiform, stabbing pain in the peri-orbital region associated with strong lacrimation and conjunctival injection with onset directly after a head trauma. This clinical picture is suggestive of the SUNCT syndrome. However, there was a sensory deficit in the V1 region indicating a post-traumatic dysfunction of the V1 trigeminal branch. We could rule out a macroscopic lesion of this nerve or its vicinity by means of MRI. Therfore so we can only speculate about the nature of the dysfunction. Onset with the trauma and the partial normalization of the deficit within 2 months after the trauma makes a microscopical lesion very likely. The abnormalities in Doppler ultrasonogaphy are most likely caused by the right-sided chronic subdural haematoma in this case. Earlier data suggested that an abnormal cerebral circulation may be part of SUNCT, but more Doppler ultrasonography data is needed to clearly answer this question (10). Without the prominent autonomic features, we would probably have to call this condition a symptomatic TN. Regarding the syndrome as a whole we see a coexistence of symptoms consistent with both SUNCT and TN. Slight sensory deficits in the V1 trigeminal branch associated with SUNCT have been described in rare cases before (10, 11). On the other hand, Sjaastad describes autonomic disturbances in some cases of trigeminal neuralgia (8/19 patients), but the combination of lacrimation (8/19 patients), conjunctival injection (3/19 patients) and rhinorrhea (2/19 patients) was only found in 2 of 19 patients diagnosed as TN, in neither case the phenomena were marked (12). In general, autonomic features have been described as a frequent symptom in TN before. But these symptoms are not considered to be marked and a combination of several phenomena must be considered a rare exception. Rather recently, several cases have been published illustrating an intimate relationship of TN and SUNCT and transformation of one into another has been proposed. Pathophysiologically, there is evidence that stimulation of trigeminal afferents can result in cranial autonomic signs, the so-called trigemino-autonomic reflex (TAR) is the key element in this context (9). The TAR consists of a brainstem connection between the Vth and the parasympathetic output of the VIIth cranial nerve. It was suggested, that the key feature of trigemino autonomic syndromes is ‘the degree, not presence of cranial autonomic activation’ (13). In our case, this approach may cause even more difficulties to reconcile the question of the proper diagnosis, as the degree and the onset of the sensory deficit clearly hints at a post-traumatic trigeminal dysfunction associated with pain and autonomic symptoms of high degree. The degree and the combination of several signs of autonomic dysfunction in this case is very unusual for TN, but due to the clear sensory deficit in V1 we prefer to call this condition a symptomatic TN with autonomic features rather than a post-traumatic SUNCT syndrome. The available literature is also consistent with the view that the clinical spectrum is a continuum: as of now, there is no proof that there is a second peak in prevalence of severe autonomic symptoms which would clearly draw a line between SUNCT syndrome and TN with increasing degrees of autonomic symptoms: SUNCT might be the upper end of a continous distribution which would also explain why the full clinical picture (located at the tail of the distribution) is a rare condition. The distinction will become more important with different therapeutic options for each condition. In the case of SUNCT syndrome and TN, the options are rather similar, but there is a difference in response rates with much lower efficiacy in SUNCT syndrome (which might again indicate either a tail in the distribution just as well as a separate condition). Ultimately, it is a question of terminology and where to draw the line depends on arbitrary definitions as long as there is no sufficient data about the distribution of the prevalence of autonomic symptoms on unselected TN/SUNCT.