Oct. 1 (UPI) -- Researchers on Thursday described a "very rare" health complication linked with COVID-19 testing: brain fluid leak.
They documented what may be the first case -- in a woman in her 40s -- in a letter published by JAMA Otolaryngology-Head & Neck Surgery.
Those who have had sinus or skull-base surgery and those with known deformities of the skull base may be at risk for cerebrospinal fluid leak and should notify test takers of their history before getting screened for COVID-19, the researchers said.
"The good news is that this is a very rare event," report co-author Dr. Jarrett E. Walsh, an ear, nose and throat specialist with the University of Iowa Hospitals and Clinics, told UPI.
"From a patient standpoint, there may be some discomfort with nasal swabs, but you should not have symptoms of persistent clear nasal drainage or significant bleeding after a swab," particularly if physicians and healthcare workers follow the U.S. Centers for Disease Control and Prevention guidelines for sample collection, he said.
During COVID-19 screening, test-takers stick a 6-inch-long swab -- what looks like a long Q-Tip -- up each nostril, stopping in the cavity between the nose and mouth.
Although people who have had the test complain of some discomfort, rumors that it causes brain damage that were circulating on social media over the summer were unfounded.
Cerebrospinal fluid, or CSF, is the clear fluid found in the brain and spinal cord that serves as a cushion and provides protection to the brain inside the skull.
Physical trauma to the brain or spine can cause leaks. If a patient loses large amounts of the fluid, that can lead to severe complications, including brain infection, paralysis and coma, according to the Spinal CSF Leak Foundation.
Symptoms of such a leak include headaches, neck stiffness and light sensitivity.
In the case reported by Walsh and his colleagues, the woman reported these symptoms, as well as a metallic taste in her mouth and severe runny nose, after undergoing COVID-19 screening.
She had a history of intracranial hypertension -- elevated CSF pressure in the brain -- and had undergone surgery to remove nasal polyps more than 20 years earlier.
MRI and CT scans confirmed that she had CSF leak and identified a pre-existing skull-base defect. The skull base is essentially the "floor" beneath the brain.
She was admitted to the hospital and underwent surgery to repair the leak and skull-base defect and has since recovered.
"I would certainly not want to discourage anyone from [COVID-19] testing, but it should be done correctly, according to the CDC protocols," Walsh said.
"Those who have had prior skull base surgery, extensive sinus surgery or [are at risk] for spontaneous CSF leaks, like intracranial hypertension, should alert testers or consider alternative testing types if available."