Endgames Picture Quiz

A pain in the neck type of headache

BMJ 2013; 346 doi: http://dx.doi.org/10.1136/bmj.f2509 (Published 29 April 2013) Cite this as: BMJ 2013;346:f2509
  1. Rafiqu Rahman Shabiyulla, anaesthetic trainee
  1. 1Department of Anaesthetics, Crosshouse Hospital, Kilmarnock KA2 0BE, UK
  1. Correspondence to: R Shabiyulla r.shabiyulla{at}nhs.net

A 29 year old right hand dominant chef presented to the emergency department with a four day history of feeling “not normal.” He was sent home from work because of a gradual onset of dull pain on the left side of his neck radiating up into his head, which was getting progressively worse, as well as “seeing two of everything.” The pain was not influenced by changes in posture. In addition, his right side felt numb and he was dropping things at work. He felt unsteady on his feet, which prompted him to seek medical advice. He thought all his symptoms had come on suddenly and were gradually getting worse. He denied any recent alcohol consumption, illicit drug use, seizure activity, head injury, or loss of consciousness. He had no medical history of note, apart from hypothyroidism, for which he was taking thyroxine.

On examination, he was alert and orientated. His blood pressure was 141/94 mm Hg and other vital signs were normal. He had moderate weakness on the right side (Medical Research Council grade 4), mainly in the upper limb, with pronator drift, and reduced sensation to pinprick, light touch, and proprioception on the same side. There was evidence of a resting and intention tremor, with dysdiadochokinesia of the upper limbs, which was more evident on the right side than the left. Furthermore, he had a broad based gait consistent with cerebellar ataxia when attempting to walk. He had an upgoing plantar response on the right and a downgoing one on the left. His pupils were equal and reactive to light, but he had diplopia on both extremes of gaze, although there was no clinical evidence of ocular palsy. Papilloedema was not detected on examination of his fundi.

Given his history and the constellation of findings on examination, a posterior fossa lesion was suspected. Because computed tomography was the only imaging modality available out of hours, a head scan was performed to rule out any serious disease (figs 1 and 2).

Questions

  • 1 What abnormalities does the computed tomogram show?

  • 2 What are the causes of this pathology?

  • 3 What other investigations would be useful?

  • 4 How should this condition be managed generally?

Answers

1 What abnormalities does the computed tomogram show?

Short answer

Haemorrhage within the midline of the pons and large prominent lateral ventricles.

Long answer

Computed tomography shows hyperdensity within the brainstem in the area of the dorsal pons, adjacent to the fourth ventricle (fig 3). There was also evidence of tonsillar herniation, with effacement of the cerebrospinal fluid space at the foramen magnum and hydrocephalus (figs 4 and 5, respectively).

Figure3

Fig 3 Computed tomogram of the head showing an acute parenchymal haematoma (arrow) within the posterior midline of the pons

Figure4

Fig 4 Computed tomogram of the head showing evidence of tonsillar herniation in a region where cerebrospinal fluid space at the foramen magnum has been replaced by cerebral parenchymal tissue (arrow)

Figure5

Fig 5 Computed tomogram showing large prominent lateral ventricles (arrows), indicative of hydrocephalus

2 What are the causes of this pathology?

Short answer

Hypertension, cerebrovascular malformations, trauma, primary or secondary tumours.

Long answer

The most common cause of pontine haemorrhage is hypertension, which accounts for about 80-90% of cases.1 Other causes include vascular malformations, anticoagulation, tumours or metastases, and diseases that cause macrovascular and microvascular damage.2 3 4 5 6 Such diseases include diabetes, hyperlipidaemia, and connective tissue disorders.7 Rare precipitants include contrast agents used for myelography and coronary angiography as well as methamphetamine.8 9 A single case report mentions a mechanically ventilated patient who developed a pneumothorax that caused an air embolus to induce bleeding in the pons.10

Some conditions can mimic a pontine haemorrhage. Patients sometimes present with reduced consciousness and pinpoint pupils but normal imaging results. These conditions include drug overdoses, including opioid analgesics, antipsychotics, and lithium.11 12 Because overdose of an opioid analgesic is more common than pontine haemorrhage, it is vital to obtain a good history from the patient or from collateral sources so that specific definite treatment can be started without delay.

Given this patient’s neck pain, diplopia, and unsteadiness, together with the multiple posterior circulation findings on examination, a diagnosis of vertebrobasilar dissection could be considered. Head or neck pain occurs in 50-75% of all dissections and the obstruction of blood flow through the dissected vessel may lead to dysfunction of the territory supplied.13 However, several factors make this diagnosis less likely. There were no intrinsic or extrinsic factors that would have precipitated this pathology and the imaging studies detected no disease within the vertebral artery lumen.

In cases where the diagnosis is not easily established, haematological and vasculitic causes need to be considered and a more extensive vasculitic and haematological investigation is needed. Such causes include thrombocytopenia, haemophilia, von Willebrand disease, and systemic lupus erythematosus.14

3 What other investigations would be useful?

Short answer

Magnetic resonance imaging of the brain, cerebral angiography, computed tomography angiography, and magnetic resonance imaging angiography. Blood tests to identify vasculitic, haematological, and coagulopathic causes are indicated if the diagnosis is unclear.

Long answer

Cerebral angiography and magnetic resonance imaging can be used to demonstrate small bleeds and help identify the cause. Computed tomography has a generally high sensitivity for detecting fresh haemorrhages but is less useful in demonstrating the underlying cause of the bleed.15 In addition, computed tomography is often used initially to evaluate patients in the emergency setting. Digital subtraction angiography, computed tomography angiography, and magnetic resonance angiography also have their uses, although magnetic resonance imaging (MRI) remains the gold standard because of its high sensitivity and specificity.16

MRI images that were obtained the next day in a tertiary neurosurgical centre (fig 6 and 7) showed a well circumscribed heterogeneous lesion within the pons. Figure 6 also shows descent of the cerebellar tonsils through the foramen magnum by 12 mm, although this was thought to be long standing (Chiari I malformation). The appearance of the heterogeneous lesion was in keeping with a pontine cavernoma.

Figure6

Fig 6 T1 weighted sagittal FLAIR (fluid attenuated inversion recovery) magnetic resonance imaging scan of the head (without gadolinium) showing the heterogeneous lesion within the pons and the herniation of the cerebellar tonsils through the foramen magnum (arrows)

Figure7

Fig 7 T2 weighted axial magnetic resonance imaging scan of the head (without gadolinium) showing the typical “popcorn” appearance of a cerebral cavernous malformation and a peripheral rim of hypointensity consisting of surrounding oedema and deposition of haemosiderin.17

Cavernous malformations are one of the four major types of vascular malformation seen within the central nervous system.18 Originally thought to be rare, because of improvements in neuroimaging techniques, they are now known to be more common. Postmortem studies indicate that they occur in less than 1% of the general population, and they are thought to constitute about 15% of all vascular malformations.18 19 20 21 They appear as well circumscribed lobulated lesions, with a reticulated core of heterogeneous signal intensity on T1 and T2 weighted MRI sequences, which results from thrombosis, fibrosis, calcification, and haemorrhage. Extracellular and intracellular methaemoglobin and thrombosis are responsible for the high intensity signal within the lesion, whereas calcifications, fibrosis, and acute and subacute blood are responsible for the low signal areas. T2 weighted and gradient echo images show a peripheral ring of hypointensity that corresponds to the deposition of haemosiderin and iron in the surrounding brain parenchyma.15

The different types of vascular malformation have unique histological and radiological properties that help identify them. For example, a cerebral arteriovenous malformation is easily delineated on digital subtraction angiography and, to a certain extent, magnetic resonance angiography.22 Capillary telangiectasias are small and cannot be seen on computed tomography or digital subtraction angiography, making MRI the investigation of choice.23 24 Cavernous malformations are identifiable on MRI but cannot be seen on magnetic resonance angiography or on digital subtraction angiography.15 19 Developmental venous anomalies, also known as cerebral venous angiomas, are the most common vascular malformations. They generally have low complication rates, although when associated with a cavernous malformation (seen 8-33% of cases; the combination is known as a mixed vascular malformation), their complication rates become similar to that of the associated lesion.25 Developmental venous anomalies can be identified on computed tomography, MRI, and digital subtraction angiography.26

4 How should this condition be managed generally?

Short answer

Assess with the ABC (airway, breathing, circulation) approach and manage the patient in a centre with immediate access to neurosurgical expertise. The Glasgow coma scale score and pupil size should be monitored regularly to allow for reimaging and prompt action if deterioration occurs. Consider treatment of associated hydrocephalus with an external ventricular drain if the patient has signs of increased intracranial pressure. Conservative treatment with serial imaging and watchful waiting. Longer term management includes blood pressure management (also important in the primary phase) and consideration of surgical intervention after initial recovery.

Long answer

The patient should first be assessed (ABC; airway, breathing, circulation) to determine whether failure of airway maintenance is imminent because of a reduced Glasgow coma score. Seizures sometimes occur and should be managed as appropriate with benzodiazepines and anticonvulsants. Treatment for cavernous malformations, regardless of whether they have bled, is divided into surgical and conservative management. Surgery may be needed to control seizures, reduce the risk of recurrent haemorrhage, and improve neurological state.27 However, this needs meticulous planning and must be tailored to individual need. Radiosurgery also has a role but is still evolving.15 28 The location of the lesion also influences management because it is riskier to access deeper lesions than more superficial ones.15 28 29 30 The mainstay of treatment is conservative if the cavernoma has not bled and if the lesion is too deep for surgical intervention.29 Conservative treatment consists of blood pressure management and control of glucose and lipid levels if appropriate. Patients are prescribed analgesics for symptom control. They are also prescribed laxatives to ensure that they do not strain when defecating, which can increase intracranial pressure.

The need for evacuation of the haematoma or drainage of the hydrocephalus depends on the size of the bleed, the extent of deterioration in consciousness state, the imminent danger of a rising intracranial pressure, and the likelihood of achieving a good neurological outcome after decompression. Haemorrhage associated with a cavernous malformation without a history of a haemorrhagic episode is about 1% a year, but with a history this rises to 60% a year.29 Overall mortality is 40-50% in patients with a pontine haemorrhage.1

All forms of treatment should be carried out in centres with expertise in neuroscience and where the patient’s mental state can be monitored, so that any deterioration can be detected. This may be in the form of routine neurological observations or through the monitoring of intracranial pressure. As a guide to treatment, imaging should be readily available and carried out periodically to monitor the progress of the haematoma.

Patient outcome

After computed tomography and discussion with the neurosurgical team, the patient was transferred to the regional neurosurgical centre, where he underwent MRI the next day, which confirmed the presence of a brainstem cavernoma. He was kept in hospital for 48-72 hours to monitor his neurological state, which did not deteriorate, and was discharged home with a course of laxatives and simple analgesics. In addition, outpatient MRI was booked (to be carried out within four weeks) and an ophthalmology appointment arranged to assess his diplopia.

The patient’s symptoms, although still present, had largely improved and full functional recovery was almost complete three weeks after his initial admission. The diplopia was gradually improving and had completely resolved by the end of four weeks, so his ophthalmology review was cancelled. Figures 8 and 9) show MRI scans performed four weeks after the initial event.

Figure8

Fig 8 T1 weighted sagittal FLAIR (fluid attenuated inversion recovery) magnetic resonance imaging scan of the head (without gadolinium) showing that the pontine cavernoma had not increased in size and that the bleeding had resolved (arrow) when compared with fig 6

Figure9

Fig 9 T2 weighted axial magnetic resonance imaging scan of the head (without gadolinium) showing resolution of the surrounding oedema and maturation of the blood products within the central cavernous lesion (arrow) compared with fig 7

The patient was discussed at a neurovascular multidisciplinary team meeting six weeks after the event, and it was decided to continue with conservative management through serial imaging and regular outpatient reviews.

Notes

Cite this as: BMJ 2013;346:f2509

Footnotes

  • Competing interests: I have read and understood the BMJ Group policy on declaration of interests and declare the following interests: None.

  • Provenance and peer review: Not commissioned; externally peer reviewed.

  • Patient consent obtained.

References