Forensic Sci Med Pathol (2013) 9:277–279 DOI 10.1007/s12024-012-9381-7
LESSONS FROM THE MUSEUM
Giant basilar artery aneurysm and unexpected death Roger W. Byard
Accepted: 31 August 2012 / Published online: 16 September 2012 Ó Springer Science+Business Media, LLC 2012
Clinical presentation A 55-year-old woman was admitted to hospital with a 2 day history of increasing headaches followed by drowsiness and confusion with vomiting. Her past history included a cerebrovascular accident 11 years previously with a residual right hemiparesis. There had been a transient episode of vertigo and left hemi-anesthesia 2 years after this, with no subsequent neurological symptoms or signs. On admission she was semicomatose but rousable with an elevated blood pressure of 190/125. On examination she demonstrated signs of her previous cerebrovascular accident with pareses of the right sixth, seventh and twelfth cranial nerves, right sided limb weakness with hyper-reflexia, and bilateral positive Babinski signs. Her respiration was described as periodic and stertorous. Her condition continued to deteriorate and she died the following day before a diagnosis could be established.
smaller extension measured 1 9 1 9 2 cm (Fig. 2). The aneurysm contained postmortem blood clot. Sectioning of the brain revealed marked symmetrical dilatation of the lateral and third ventricles, in keeping with the effects of obstruction to cerebrospinal fluid flow, with no macroscopic evidence of previous infarction (Fig. 3). The specimen had been retained for museum display and so no further sectioning or sampling for histology had been undertaken. Moderate atherosclerosis was present in the coronary arteries and aorta. No other significant underlying organic diseases were present which could have caused or contributed to death.
Cause of death Brainstem compression from a large aneurysm of the basilar artery.
Autopsy findings
Museum reference
At autopsy the body was that of an adult Caucasian female of around the stated age of 55 years. Her height was 173 cm, weight 71 kg, and body mass index (BMI) 23.7. The major findings were limited to the brain which showed evidence of swelling with gyral flattening. The basilar artery was replaced by a bilocular aneurysm; the main part of the aneurysm measured 4 9 4 9 6 cm (Fig. 1), and a
This case, # 19393, can be located at the Hans Schoppe Museum of Pathology at the School of Medical Sciences, Medical School North, The University of Adelaide, Frome Rd, Adelaide, SA, Australia.
R. W. Byard (&) Discipline of Anatomy and Pathology, School of Health Sciences, The University of Adelaide, Level 3 Medical School North Building, Frome Road, Adelaide 5005, Australia e-mail:
[email protected]
Discussion Aneurysms representing pathological areas of arterial dilation may be found in all parts of the cerebral vasculature [1]. The incidence of cerebral aneurysms and associated subarachnoid hemorrhage varies among countries, with high rates in both Japan and Finland [2, 3]. The
123
278
Forensic Sci Med Pathol (2013) 9:277–279
Fig. 1 Base of the brain showing replacement of the basilar artery with a giant aneurysm
incidence overall has been estimated at 10.5 cases/100,000 individuals. Cerebral aneurysms are rare in infants and children, although they do occur [4, 5], increasing in incidence to peak at 55–60 years of age. More males are found under 50 years, with an increase in females after this, producing an overall male to female ratio of 1.6:1 [6]. In 20–30 % of cases intracerebral aneurysms are multiple and there is an association with a number of conditions including hypertension, connective tissue disorders such as Marfan and Ehlers Danlos syndromes and pseudoxanthoma elasticum, Osler-Weber-Rendu syndrome, systemic lupus erythematosus, Moyamoya syndrome, polycystic kidney disease, coarctation of the aorta, arteriovenous malformations, a-1-anti trypsin deficiency, neurofibromatosis type 1, tuberous sclerosis and fibromuscular dysplasia [7]. Pregnancy increases the risk of rupture with lethal subarachnoid hemorrhage [6]. Genetic markers have been associated with intracranial aneurysms, possible involved in disruption of extracellular matrix within arterial walls [8]. The etiology of cerebral aneurysms is variable, with the majority of cases (90 %) consisting of so-called saccular, berry or congenital aneurysms. These tend to arise in major cerebral arteries such as the anterior communicating artery, in the anterior aspect of the brain around the Circle of Willis [6]. It is believed that the interaction of congenital
123
Fig. 2 A close-up view of the aneurysm showing the brainstem, cerebellum and vertebral arteries below, with a smaller extension of the aneurysm to the upper right
weaknesses in vessel walls with hypertension or atherosclerosis predisposes to ballooning of vessels at certain points. Other causes of cerebral aneurysms include mycotic aneurysms from bacterial endocarditis [9], neoplasia and trauma. Giant aneurysms are defined as those greater than 25 mm in diameter and range from 2 to 13.5 % of cases [10, 11]. Aneurysms may grow in size over time, a feature that has been linked to excessive alcohol consumption [12]. The abnormality reported in the present case represents a dolichoectatic or fusiform aneurysm. These account for approximately 7 % of intracranial aneurysms, are associated with atherosclerosis, and are usually found in the vertebrobasilar system where they classically involve the entire length of a vessel [13]. Aneurysms, particularly those that are saccular, usually present with catastrophic headaches due to rupture with subarachnoid hemorrhage. Dolichoectatic aneurysms are, however, different and tend to present, as in the reported case, with mass effects. This can produce a variety of presentations ranging from ataxia and quadriparesis, to reduced levels of consciousness and
Forensic Sci Med Pathol (2013) 9:277–279
279
clinical deterioration may occur once a critical size is reached. Acknowledgments Dr JS Gower is acknowledged and thanked for performing the original autopsy.
References
Fig. 3 Symmetrical dilation of the ventricles in keeping with acute hydrocephalus
hypoventilation. Bulbar palsies, central sleep apnea and sudden death may also be manifestations [10, 14]. Hydrocephalus results from obstruction or deformation of the third ventricle or foramen of Monro, similar to other critically-placed masses such as colloid cysts [15], and distal embolization may occur [13]. The relation of the basilar artery aneurysm to the previous cerebrovascular accident and transient neurological symptoms is unclear. A difficulty with the surgical treatment of dolichoectatic compared to berry aneurysms, is the lack of a definable neck to enable clipping [13]. In conclusion, the reported case demonstrates a rare cause of unexpected death involving brain stem compression and obstruction to cerebrospinal fluid outflow by a giant dolichoectatic basilar artery aneurysm. Although obviously a chronic condition it is apparent that precipitate
1. Krings T, Mandell DM, Kiehl TR, Geibprasert S, Tymianski M, Alvarez H, terBrugge KG, Hans FJ. Intracranial aneurysms: from vessel wall pathology to therapeutic approach. Nat Rev Neurol. 2011;20:547–59. 2. Vlak MHM, Algra A, Brandenburg R, Rinkel GJE. Prevalence of unruptured intracranial aneurysms, with emphasis on sex, age, comorbidity, country, and time period: a systematic review and meta-analysis. Lancet Neurol. 2011;10:626–36. 3. Rinkel GJ. Natural history, epidemiology and screening of unruptured intracranial aneurysms. J Neuroradiol. 2008;35:99–103. 4. Byard RW, Bourne AJ, Hanieh A. Sudden and unexpected death due to hemorrhage from occult central nervous system lesions. Pediatr Neurosurg. 1991–92;17:88–94. 5. Byard RW. Vascular causes of sudden death in infancy, childhood, and adolescence. Cardiovasc Pathol. 1996;5:243–57. 6. Vates GE, Zabramski JM, Spetzler RF, Lawton MT. Intracranial aneurysms. In: Mohr JP, Choi DW, Grotta JC, Weir B, Wolf PA, editiors. Stroke. pathophysiology, diagnosis and management. 4th ed. Oxford: Churchill Livingstone; 2004. p. 1279–335. 7. Byard RW. Sudden death in the young. 3rd ed. Cambridge: Cambridge University Press; 2010. 8. Ruigrok YM, Rinket GJE, Wijmenga C. Genetics of intracranial aneurysms. Lancet Neurol. 2005;4:179–89. 9. Byramji A, Gilbert JD, Byard RW. Sudden death as a complication of bacterial endocarditis. Am J Forensic Med Pathol. 2011;32:140–2. 10. Hayashi T, Hirayama N, Ro A, Kageyama N, Ishida Y, Tsuneyama K, Kimura A, Fukunaga T, Kondo T. Severe brainstem compression by an unruptured giant vertebral aneurysm: an autopsy case. Leg Med. 2007;9:322–5. 11. Sharma BS, Gupta A, Ahmad FU, Suri A, Mehta VS. Surgical management of giant intracranial aneurysms. Clin Neurol Neurosurg. 2008;110:674–81. 12. So TY, Dowling R, Mitchell PJ, Laidlaw J, Yan B. Risk of growth in unruptured intracranial aneurysms: a retrospective analysis. J Clin Neurosci. 2010;17:29–33. 13. Anson JA, Lawton MT, Spetzler RF. Characteristics and surgical treatment of dolichoectatic and fusiform aneurysms. J Neurosurg. 1996;84:185–93. 14. Vaahtera K, Lunetta P. Death associated with an unruptured giant intracranial aneurysm. Leg Med. 2010;12:200–2. 15. Byard RW, Moore L. Sudden and unexpected death in childhood due to a colloid cyst of the third ventricle. J Forensic Sci. 1993;38:210–3.
123
