Early detection of vertebral artery dissection

Abstract

A 36-year-old female patient presented to hospital with a 1-week history of occipital headache. It was sudden onset following a fall into a swimming pool. Examination was unremarkable. CT angiogram brain scan showed right vertebral artery dissection with a 1 cm dissection flap and a 3 mm left middle cerebral artery aneurysm. She was discharged on aspirin, with outpatient neurology clinic follow-up.

Background

Vertebral artery dissections (VADs) can be described as either spontaneous or traumatic.¹ Traumatic dissection may be caused by penetrating or blunt force, including excessive flexion or extension of the neck.² Chiropractic manipulation is a well-documented precipitating factor.³

Many conditions have been identified in association with spontaneous dissection. Such as primary disease of arterial wall (eg, fibromuscular dysplasia (FMD)) and genetic connective tissue abnormalities (eg, Ehlers-Danlos syndrome, Marfan syndrome, osteogenesis imperfecta).^{4 5}

Although rare event, they are one of the most recognised causes of stroke in those aged under 45 years.⁶ Injury to the vertebral artery can lead to potentially fatal posterior circulation ischaemia.

This case report explores the presenting symptoms of a woman who was diagnosed with VAD.

Case presentation

A 36-year-old female patient presented to hospital with a 1-week history of occipital headache. While on holiday, the patient had slipped into a swimming pool accidentally. On exiting the water, she suddenly experienced neck pain with a headache. There was no history of direct head injury.

She described the pain as throbbing and pulsatile in nature. It was primarily in the occipital region and radiated down the cervical region. Visual Analogue Pain scale was 8/10. The pain lasted for around 90 min, which was eased with paracetamol and ibuprofen. The pain returned at a similar intensity and persisted despite simple analgesia. Therefore, she attended the emergency department.

She has no significant medical or family history. She is a smoker and consumes minimal alcohol.

Her blood pressure was 181/102 mm Hg. Neurological examination was unremarkable; neck flexion did not worsen the pain and she denied photophobia. The remaining clinical examination was normal.

Investigations

Her blood tests, urine dip and ECG were all unremarkable.

Due to the history and description of symptoms, an urgent CT angiogram was requested to rule out dissection. This confirmed a right VAD with a 1 cm dissection flap, as well as a 3 mm left middle cerebral artery (MCA) aneurysm (figure 1). Doppler ultrasound was not performed, as a CT angiogram is considered more sensitive and is able to highlight if any bleeding was present.⁷

Figure 1.

Axial view of CT angiogram of the patient. Red box indicating right vertebral artery dissection with a 1 cm dissection flap.

Following discussion with neurology department, a MRI brain with diffusion-weighted imaging was performed to rule out acute infarct. This showed no evidence of bleeding.

Differential diagnosis

• Intracranial dissection.

• Headaches secondary to hypertension.

• Atypical migraine.

Treatment

The patient was admitted for observation and analgesia. Neurology advised medical management for the right VAD. She was started on a 2-week course of aspirin 300 mg followed by 6 months of aspirin 75 mg, with neurology clinic follow-up in 6 months.

A neurosurgery outpatient clinic appointment was scheduled for left MCA aneurysm. She was also commenced on amlodipine 5 mg and referred for 24-hour blood pressure monitoring.

Outcome and follow-up

Repeat CT angiogram at 6 months showed the right VAD not to have healed. She has been continued on aspirin 75 mg for another 6 months, with further neurology clinic follow-up.

Neurosurgery deemed the aneurysm to be of very low risk of rupture, and she will be managed with an annual MRI angiogram.

The 24-hour blood pressure monitoring did not show any significant abnormality.

Discussion

VAD is a rare clinical event. Despite this, it is the leading cause of ischaemic strokes in patients under 45 years of age (13%).⁸

Cervical artery dissection can be either the carotid or vertebral arteries. The combined incidence is around 3.5–4.5 per 100 000 with carotid artery dissection being twice as common as VAD.⁹

Presentation can be non-specific symptoms, such as headache, neck pain or vertigo. Therefore, can be incorrectly investigated for more common differentials such as subarachnoid haemorrhage or meningitis. Rarely, VAD can present as a cause of isolated radiculopathy. Cases have been reported of an extracranial VAD compressing cervical nerve roots and causing acute cervicobrachial pain with arm weakness.¹⁰

In 2000, the Canadian Journal of Neurological Sciences published an article on warning symptoms in VAD.¹¹ This retrospective study looked at the early symptoms and warning signs which may help in the early identification and treatment of patients with VAD. They identified 26 patients over a 10-year time period. Nearly all patients have pain as a presenting feature (88%), with most as headache in the occipital region.

As clinicians, patient’s experience of acute pain can be difficult to interpret. It can be shaped by a host of psychological as well as physical factors—for example, anxiety or long-standing chronic pain.¹² Only 50% of the patients in the previous study found their pain to be of a worrying intensity. The delay in presentation to the hospital can increase patient’s risk of serious complications, such as stroke or haemorrhage. In this case, the intensity of pain lead her to seek hospital care.

An important finding to discuss in this case is that of the left MCA aneurysm. FMD is a non-inflammatory disease that predominantly affects young women. It can result in a wide variety of arterial manifestations including aneurysm and dissection—both of which were present in this patient.¹³ It is most commonly found in the renal and extracranial carotid and vertebral arteries. The prevalence of symptomatic renal artery FMD is approximately 4 per 1000, with the prevalence of cervicocranial FMD half of that.¹⁴ The renal function of our patient was within the normal limits. The radiological imaging showed no evidence of the characteristic ‘string of beads’ feature often reported in FMD-related cases. This is as a result of alternating stenosis and dilatations.¹⁵ Due to the significant events described by the patient leading up to the symptoms, traumatic dissection seemed the most likely cause. While an important correlation to be aware of, neurosurgical review deemed the left MCA be most likely incidental.

Overall, the prognosis of patients with VAD is relatively good, with low mortality and morbidity rates. However, diagnosis should not be missed, as early treatment can prevent ischaemia and death.¹⁶

Patient’s perspective.

The pain in my neck and head was excruciating, ‘thump thump’ was the feeling. Paracetamol and ibuprofen worked initially, and the pain became bearable. I didn’t feel nauseous or have any vision trouble. It was a relief when the CT/MRI results were given. I took the medication I was given, and more or less got back on with my life. Looking back now, I realised how lucky I was I could still get on with my life.

Learning points.

• In patients with blunt neck trauma or twisting injury, consider differential diagnosis of a dissection.

• Persistent symptoms with relevant history should prompt wider differential diagnosis.

• Choosing the right diagnostic imaging modality in discussion with radiologist helps to arrive at the right diagnosis.