Intracranial hypertension due to levothyroxine use

Idiopathic Intracranial Hypertension following Levothyroxine Replacement Therapy: Systematic Review and a Case Report

The data on the characteristics of patients with idiopathic intracranial hypertension (IIH) following levothyroxine (LT4) replacement are limited. Here, we report a case and systematically review published cases of idiopathic intracranial hypertension (IIH) following levothyroxine (LT4) replacement. The systematic review was performed as per the PRISMA guidelines. Our patient is a 46-year-old lady with hypothyroidism (thyrotropin: 319 mIU/L, free thyroxine: 0.04 ng/dl), treated with 100 μg.d of LT4 and presented a month later with headache, visual diminution, bilateral lateral rectus palsies, and papilledema. Cerebrospinal fluid (CSF) pressure was 32 cmH2O. Drainage of CSF, oral acetazolamide, and modification of LT4 dose resulted in prompt symptomatic improvement and complete reversal of IIH. In the systematic review (n = 21), the median age of patients (7 males) was 13 (IQR: 8.8- 26.5) years. The median duration of hypothyroid symptoms was 4 (n = 10, IQR: 0.44-6.25) years whereas that from initiation of LT4 replacement to the diagnosis of IIH was 2 (n = 20, IQR: 1.17-4) months. Initial median serum thyrotropin and thyroxine were 100 (n = 14, IQR: 72.5-421.6) mIU/L, and 1.13 (n = 12, IQR: 1.0-2.45) μg/dl which changed to 2.2 (n = 7; IQR: 0.23-3.40) mIU/L and 8.90 μg/dl (n = 8, IQR: 6.43-14.85 μg/dl), respectively at diagnosis of IIH after LT4 treatment with median daily LT4 doses of 0.89 (n = 8, IQR: 0.60 - 1.17) times the maximum recommended dose for age. To conclude, we report an adult woman with IIH following LT4 replacement for primary hypothyroidism, a rare entity. Pediatric age, prolonged symptom duration, and use of higher LT4 replacement dose may be associated with IIH following LT4 replacement.

High rates of (treated) hypothyroidism among chronic migraine patients consulting a specialized headache clinic: are we missing something?

BACKGROUND

Roughly three percent of episodic migraine patients evolve into the most burdensome chronic form of this condition every year. While some of the determinants behind this transformation are well established, others are still ill defined. Hypothyroidism is a prevalent endocrinological disorder that can both produce a secondary headache or aggravate a pre-existing primary headache disorder such as migraine.

OBJECTIVE

We aimed to re-assess the association between hypothyroidism and chronic migraine controlling for factors such as hormone replacement treatment status and bodyweight.

METHODS

We retrospectively analyzed the medical records of episodic and chronic migraine patients who consecutively consulted our headache clinic in order to determine the prevalence of adequately treated hypothyroidism in each group. Only patients receiving a stable dose regimen were included. The body mass index and other possibly confounding covariates were also collected.

RESULTS

Data from 111 migraine patients was included for analysis. Most (88.6%) of chronic migraine sufferers were overusing acute medication. Treated hypothyroidism was significantly more prevalent in chronic migraine patients (29.55%) compared to episodic migraine patients (8.96%). This association was independent of the patients' body mass index or other variables.

CONCLUSION

Alterations of neuronal metabolism, deficient calcitonin release, or focal inflammation causing local hormonal deactivation might explain why hypothyroidism, in spite of levothyroxine replacement therapy, is associated with migraine chronification. Further studies evaluating these factors are warranted.