The coronavirus-19 (COVID-19) outbreak was first identified in Wuhan, Hubei Province, China in December 2019. Given its rapid global spread, the World Health Organization defined it as a “pandemic” on March 11, 2020. Testing for the virus soon became a vital tool in the arsenal of tactics used to limit and control its spread. The United States Centers for Disease Control currently recommends COVID-19 testing for patients who are symptomatic, who are in close contact with an infected person, who take part in higher-risk activities or who have been asked by their healthcare provider to have the test.
The nasal or nasopharyngeal swab test is commonly used for molecular or antigen testing for COVID-19. Nasal swabs are considered to be quick and easy; however, the test can lead to adverse events, including pain, epistaxis and cerebrospinal fluid (CSF) leak. Here, we present the fourth reported case of CSF leak following nasal swab testing for COVID-19.
Given the morbidity of a CSF leak and the frequency of the nasopharyngeal swab being performed, healthcare providers should be aware of this rare potential complication and its presentation.
A 45-year-old woman was referred for evaluation of right-sided rhinorrhea. She underwent a COVID-19 nasal swab test three weeks prior and, shortly following this test, developed unilateral clear rhinorrhea. This worsened when leaning forward and with straining.
A beta-2 transferrin test sent by an outside otolaryngologist was positive. On physical examination, she had clear rhinorrhea that was induced with leaning forward. On rigid nasal endoscopy, there was no obvious encephalocele. Computed tomography imaging showed a defect in the right cribriform plate (see Figure 1). She underwent endoscopic endonasal repair of the CSF leak. A lumbar drain was placed, and intrathecal fluorescein was infused. A small encephalocele in the right skull base was identified and reduced (see Figure 2). Multiple defects were visualized in the right cribriform plate.
These defects were repaired using acellular human dermal matrix and a vascularized pedicled nasoseptal flap (see Figure 3) given the numerous skull base defects. Gelfoam and a Merocel pack were used to support the reconstruction site. She was admitted postoperatively for monitoring and lumbar drain management. She had an uneventful postoperative course and is doing well.
This is the fourth reported case of CSF leak following the nasal swab test for COVID-19. The first case of iatrogenic CSF leak was reported in November 2020 in a patient with a previously undiagnosed skull base defect. In that case, the nasal swab was thought to have penetrated a pre-existing encephalocele in the fovea ethmoidalis.1 Two other cases describe a traumatic injury of the skull base in the area of the cribriform plate.2, 3 One patient developed delayed meningitis and was treated conservatively with spontaneous closure of the leak.3 Similar to the first reported case, our patient had a pre-existing encephalocele and had multiple skull base defects discovered intraoperatively. In all four cases, the patients were female and 30–40 years of age, a typical group of patients with benign intracranial hypertension and encephalocele.
Qualitative real-time polymerase chain reaction (RT-PCR) of nasopharyngeal secretions is considered to be the gold standard test for COVID-19. As of April 10, 2021, more than 388 million COVID-19 tests have been administered in the United States.4 The nasopharyngeal swab test is generally considered to be safe, easy and quick. However, incorrectly positioned swabs, such as those introduced only a few centimeters into the nasal cavity or positioned vertically may lead to an inaccurate test result. Furthermore, vertically positioned swabs may lead to iatrogenic injury of intranasal structures and the skull base.
“Since the outbreak of COVID-19, some have suggested implementing collaboration between otolaryngologists and personnel dedicated to collecting nasal swabs.”
Formal educational programs on nasopharyngeal swab testing have been developed after previous epidemics, such as the Middle Eastern Respiratory Syndrome Coronavirus epidemic.5 Since the outbreak of COVID-19, some have suggested implementing collaboration between otolaryngologists and personnel dedicated to collecting nasal swabs. Otolaryngologists have provided live endoscopic demonstrations of nasopharyngeal swab testing to help improve understanding of intranasal anatomy and swab positioning.6
Although the United States Food and Drug Administration provides a link on their website for providers to report adverse events or side effects related to the use of COVID-19 tests,7 the incidence of such complications is not well known.8 Given the potential morbidity of a CSF leak, healthcare providers should be aware of this potential complication.
Should a patient develop unilateral, clear rhinorrhea following a nasal swab test, consideration should be given to an iatrogenic CSF leak and evaluation by an otolaryngologist should be sought. Patients with predisposing conditions, such as preexisting skull base defects, prior skull base or extensive sinus surgery, or distorted anatomy, may be at higher risk for CSF leak. These patients should be made aware of this potential complication and alternative methods of testing, such as an oropharyngeal swab or saliva test. The incidence of iatrogenic CSF leak is extremely low and should not deter patients from obtaining a COVID-19 test.
Given the increasing use of the nasal swab test for detection of COVID-19, healthcare providers should be aware of its potential complications. Development of unilateral rhinorrhea or severe pain following a nasal swab test may indicate an iatrogenic injury to the skull base. Improved understanding of intranasal anatomy and swab positioning may help prevent this complication.