Background: Endocrine dysfunction, including thyroid function, has been known to affect cerebral vascular dysfunction. Hypothyroidism has been shown to cause mucopolysaccharide deposition which has been associated with the weakening of blood vessel walls and aneurysm formation in some case reports. However, the connection between hypothyroidism and cerebral aneurysm has not been well studied. We hypothesized that hypothyroidism maybe associated with occurrence of cerebral aneurysms.
Methods: We performed a retrospective case-control study of consecutive patients receiving cerebral angiography at our tertiary-care academic medical center. Inclusion criteria included undergoing 3-vessel angiography. Exclusion criteria included any ruptured aneurysm or previous intracranial hemorrhage. Medical history of hypothyroidism was noted along with all other risk factors. The control group of patients did not have any intra-cranial abnormality on angiography. Patients with cerebral aneurysm were matched with controls for known risk factors of cerebral aneurysm, including: age, hypertension, and smoking history. Cases were further subdivided base on gender given females are known to have higher incidence of hypothyroidism.
Results: From 2008 through 2013, 82 female and 59 male patients with aneurysms were identified for this study and were matched with equal numbers of controls. Among women, hypothyroidism was present in 20.7% (17/82) among patients with cerebral aneurysms vs. in only 6.1% (5/82) among matched controls: odds ratio (OR) 4.03 (95% CI 1.41-11.51, p=0.01). Among men, 8.5% (5/59) cases and 0/59 controls had hypothyroidism, showing no significant association, with an odds ratio of 12.01 (95% CI 0.65-222.3, p=0.095).
Conclusion: We found a significant association of history of hypothyroidism with cerebral aneurysm in women in our patient cohort. Given the potential pathophysiologic connection between hypothyroidism and vascular wall dysfunction, this should be explored further.