A case of sudden visual loss due to a brain tumour after mRNA injection

In a case study report published in December, a 60-year-old woman experienced sudden visual loss in her left eye three days after receiving her fourth dose of the Pfizer-BioNTech covid injection.

Her acute visual loss was due to an expanding pituitary adenoma, in other words, a brain tumour. 

The covid injection represents a new potential contributor to the enlargement of the pituitary gland, the authors wrote.

Published in the journal Cureus on 17 December 2023, two ophthalmologists in Thailand reported “an interesting case” of a 60-year-old woman that supports the covid injection as “one of the possible risk factors aggravating” expanding pituitary adenoma post covid injection.

The pituitary gland is a small, oval-shaped endocrine gland located at the base of the brain below the hypothalamus.

Pituitary gland tumours are brain tumours that start to grow in the pituitary gland. Most pituitary tumours are non-cancerous or benign. Benign pituitary gland tumours are also called pituitary adenomas.

“A pituitary adenoma is an anterior pituitary tumour, usually benign and slow-growing. Non-functioning tumours can compress surrounding organs, leading to ill effects such as headache, visual loss, visual field defect, or hormonal deficiency,” the authors of the case report wrote.

Magnetic resonance imaging (“MRI”) of the brain and eye orbit revealed a well-defined tumour of the 60-year-old’s pituitary gland, 1.8 x 1.3 x 2.6 cm in size.  The mass caused pressure on the optic chiasm. After endocrinologists performed tests for hormonal function, a non-functioning pituitary tumour was diagnosed, the case report said.

The optic chiasm is the part of the brain where the optic nerves cross and is of primary importance to the visual pathway. Enlargement of the pituitary gland can therefore affect the functioning of the optic nerve.

A neurosurgeon removed the 60-year-old’s tumour.

After the operation, the patient’s vision gradually improved. One month after the procedure, her visual field improved considerably, and her pupil reaction and colour vision recovered. At three months, colour vision finally became normal. Six months after the surgery, her clinical condition was stable, with no residual tumour detected in the MRI.

“The vaccine has rarely been linked to transient endocrine-related complications like thyroiditis, pancreatitis, and occasional pituitary gland enlargement. These vaccine-induced effects, notably on the pituitary gland, include reports of pituitary apoplexy [bleeding] or, less frequently, pituitary hypophysitis [inflammation],” the authors wrote.

The authors noted that this case supports the covid-19 injection as one of the possible risk factors aggravating this condition.

“The emergence of subacute visual impairment, colour perception deficiencies, abnormal pupillary responses, and a pronounced visual field impairment, in comparison to the patient’s status one month post-vaccination, suggests a plausible association between the covid-19 vaccine and the development of pituitary gland enlargement,” they wrote.

Reports have highlighted diverse complications following covid-19 vaccination, with a particular focus on the endocrine system.  Among these complications, disturbances in endocrine organs, notably involving the thyroid, pancreas, adrenal glands, and pituitary gland, have garnered attention. Pituitary apoplexy, characterised by severe symptoms, such as intense headaches, diplopia, and other endocrinological abnormalities, has been observed in a significant proportion of patients experiencing endocrine disturbances post-vaccination.

Covid-19 Vaccine-Induced Expansion of Pituitary Adenoma: A Case Report, Worapot Srimanan and Somboon Panyakorn, Cureus, 17 December 2023

The precise mechanisms underlying these phenomena remain incompletely understood, the authors noted.   

It is postulated that covid-19 vaccination may trigger inflammatory or immune responses that lead to endothelial dysfunction, resulting in hyperpermeability. Given the extensive and delicate vascular network within the pituitary gland, it becomes particularly susceptible to this type of reaction. Subsequent oedema increases pituitary size.

Moreover, an immune response may also be initiated by the mRNA component of the vaccine itself, potentially causing inflammation and impairing vascular function. These combined processes culminate in a compressive effect on adjacent organs.

Covid-19 Vaccine-Induced Expansion of Pituitary Adenoma: A Case Report, Worapot Srimanan and Somboon Panyakorn, Cureus, 17 December 2023

The authors of the report advised that people who have received a covid injection should be aware of the potential ill effects of the “vaccines” and seek medical attention promptly if need be:

Reports of endocrine complications, particularly impacting the pancreas and thyroid, have emerged. Notably, the pituitary gland, a relatively rare target, has also been implicated. Additional research is required to elucidate the precise pathophysiological relationship between the covid-19 vaccine and pituitary gland disorder. Individuals receiving the vaccine should be aware of potential side effects and promptly seek medical attention in case of serious adverse events.

Covid-19 Vaccine-Induced Expansion of Pituitary Adenoma: A Case Report, Worapot Srimanan and Somboon Panyakorn, Cureus, 17 December 2023

The authors concluded:

Pituitary gland tumours are slowly growing, primarily asymptomatic, with incidental findings. Early detection, reduced aggravating factors, and specific treatment are essential. The covid-19 vaccine represents a novel potential contributor to the enlargement of the pituitary gland. Individuals with preexisting pituitary adenomas should be particularly vigilant regarding the possible side effects associated with this vaccine.

Covid-19 Vaccine-Induced Expansion of Pituitary Adenoma: A Case Report, Worapot Srimanan and Somboon Panyakorn, Cureus, 17 December 2023