‘Covid’ test caused man’s 9-month-long brain fluid leak

A man’s persistently runny nose following a COVID-19 test wasn’t caused by allergies as he suspected, but rather cerebrospinal fluid leaking from his brain, according to a new report.

The man, who lives in the Czech Republic, received a COVID-19 nasal swab test in March 2020 after he had contact with a person infected with COVID-19, according to the report, published Thursday (Sept. 9) in the journal JAMA Otolaryngology–Head & Neck Surgery. The man’s test was negative, but afterward he experienced a runny nose from just his right nostril. This symptom, which the patient mistakenly thought was due to allergies, lasted for months before he went to see a doctor in December 2020.

A CT scan of his skull showed that the man had an injury to the cribriform plate, a spongy bone that separates the nose and the brain. He was diagnosed with a cerebrospinal fluid (CSF) leak, a rare but serious condition in which the clear fluid that surrounds the brain and spinal cord leaks through a defect in the skull and out through the nose, according to Johns Hopkins University. Typically, the leakage happens from just one side of the nose, according to the Cleveland Clinic.

CSF leaks are dangerous because they can increase the risk of meningitis, which is an infection of the membranes that surround the brain and spinal cord. Still, patients can have a CSF leak for years before they develop serious problems, Live Science previously reported.