Traumatic cerebrospinal fluid leak after performing PCR test using a nasal swab for the detection of COVID-19 disease. A Systematic review

Introduction and objective: Cerebrospinal fluid leaks (CSF) can occur after trauma, this leads to a disruption between the arachnoid and the dura, frequently associated with a bone defect. The global epidemic produced by COVID-19 has generated the need for rapid tests to detect the virus in the nasal and oropharyngeal mucosa. Nasal swabs (NS) have proven to be useful in collecting nasopharyngeal specimens and therefore their use has become widespread. This diagnostic method is considered safe, but there are a number of possible complications, including one of the most feared; CSF leak. The objective of this article is to carry out an exhaustive bibliographic review of available articles that describe this complication, investigating the predisposing factors and describe a safe technique to avoid it. Method: PubMed, Web of Science and Scopus databases were searched according to PRISMA guidelines, from March 2020 to November 2021. Studies reporting clinical data of patients with CSF leak after being subjected to NS were reviewed. We focus on the alarm symptoms presented, diagnostic strategies and therapeutic management. Results: To date, eleven published cases have been reported of patients with a diagnosis of CSF leaks caused by performig a PCR test using a nasal swab. All the articles were included in this systematic review. Each article described this complication in one patient, so we have a total of eleven patients. The average age at diagnosis was 45 years, with 8 women and 3 men. The cribriform plate is the most frequently affected anatomical location. In five patients, 45,5%, the preexistance of malformation at the level of the skull base was known, which corresponds to a risk factor when suffering a CSF leaks after NS. Conclusion: Although the nasal swab test for the diagnosis of COVID-19 is considered safe, it can sometimes lead to complications. The appearance of unilateral clear rhinorrhea or post-nasal drip with a salty or metallic taste after performing a NS should alert us when diagnosing a possible CSF leak. It is extremely important to adequately instruct the health workers to perform the test, indicating the correct direction and orientation of the swab. In addition, the patient should be informed of the warning signs and symptoms. In patients with previous skull base alteration, nasal anatomy distortion or previous sinus surgeries.