Paradoxical Emboli to Artery of Percehron in Hereditary Haemorrhagic Telangiectasia
Correspondence Address: Source of Support: None, Conflict of Interest: None DOI: 10.4103/0028-3886.310068
Source of Support: None, Conflict of Interest: None
A 30-year-old lady presented was brought to the emergency room with a 1-day history of sudden onset of severe drowsiness from which she has partially improved. There was no history of fever, trauma, or seizures. There was no history of intake or any access to drugs or toxins. There was no history of any possible hypoxic episode. She was not an alcohol consumer and was taking a normal diet. She had no known co-morbidities except for history of recurrent epistaxis.
On examination, her vital parameter was normal. She was conscious but was drowsy and needed repeating prompting to comprehend and obey commands and answer questions. There was no icterus, neck stiffness or papilledema. The extra ocular movements were normal and a detailed neurological examination did not show any focal deficits.
The blood tests including the serum ammonia levels were normal. Toxic screening was normal. The B12 and folate levels were normal; CT scan of the brain and an EEG were normal. The CSF study ruled out any central nervous system infection.
Magnetic resonance imaging (MRI) of brain showed bilateral thalamic infarcts in the paramedian location suggestive of an artery of Percehron infarction [Figure 1]a. The MR angiogram and MR venogram were normal [Figure 1]b and [Figure 1]c.
Work-up for vasculitis, prothrombotic states including protein C, S Antithrombin III assays, infective endocarditis and hyperhomocystinemia were negative. Transthoracic and a Transeseophageal echo were non-contributory.
An ear, nose, and throat (ENT) evaluation (done for recurrent epistaxis) showed haemorrhagic telangiectasia present on the nasal septum, turbinate and the nasopharynx [Figure 2]c At this time it was also noted that she had telangiectatic vessels on the conjunctiva, lips, tongue, hard palate and finger tips. [Figure 2]a, [Figure 2]b and [Figure 2]d
Transcranial Doppler (TCD) bubble study which was done as part of young cryptogenic stroke work up showed grade 3 High Intensity Transient Signals (HITS) based on the International Consensus Criteria suggestive of a right to left shunt. [Figure 3]a
CT angiogram showed multiple hepatic and pulmonary arteriovenous malformations. [Figure 1]d and [Figure 1]e
This patient fulfilled Curaçao's diagnostic criteria for hereditary haemorrhagic telangiectasia (HHT) also known as Rendu-Osler-Weber syndrome.
HHT can manifest with mucocutaneous telangiectasias and arteriovenous malformations (AVMs). Depending on their locations the patients can present with a variety of clinical symptoms.
The most common presentations are with epistaxis or gastrointestinal bleeding. Paradoxical brain emboli through pulmonary AV fistulas are the cause for strokes, TIAs and cerebral abscesses in patients with HHT. Recent epidemiological studies form Europe and Japan gives the incidence of this autosomal disease one in 5–8000.
Pulmonary AV Fistulas can be seen in around 20% of patients with HHT of these 20%–30% can develop cerebral infarction or transient ischemic events.,
Artery of percheron is a rare anatomical variant The paramedian region of the thalamus is usually supplied by the thalamoperforate arteries (paramedian arteries) originating from the P1 segments of the posterior cerebral artery (PCA). Rarely, both the paramedian regions can get supplied by a single arterial trunk called the artery of Percheron (AOP). Thus pathology in this variant artery can effect both the medial thalami.
The paraventricular thalamus is active during the wakeful state, and also takes part in reward learning. Suppression of this region can cause a reduction in wakefulness and can even make the body go into a sleep inducing posture.
Bilateral paramedian thalamic infarction can result in decrease in consciousness ranging from somnolence to coma which is usually transient.
A stroke resulting from AOP occlusion is rare constituting only 0.1% and 0.3% of all ischemic strokes. Embolic occlusion was the most common aetiology in many series on AOP strokes.,
This patient had a rare presentation of a rare disease.Her stroke was due to a paradoxical emboli to the AOP from one of the pulmonary AVMs.
She was treated conservatively and her condition improved during her hospital stay. After 3 weeks she underwent endovascular coiling of the larger pulmonary AVMs [Figure 3]b to avoid future neurologic complications. She did not have any new cerebrovascular events till date (3-year follow-up).
This case highlights the importance of picking up clues from the history and examination findings which can lead us to the diagnosis in difficult cases. In this patient, we had initially overlooked the importance of her history of recurrent epistaxis and also her mucocutaneous telangiectasias were missed.
This is the first report of such a complication of HHT syndrome in the English literature to the best of our knowledge.
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Conflicts of interest
There are no conflicts of interest.
[Figure 1], [Figure 2], [Figure 3]