[Skip to Navigation]
Sign In
September 9, 2021

Cribriform Plate Injury After Nasal Swab Testing for COVID-19

Author Affiliations
  • 1Clinic of Otorhinolaryngology and Head and Neck Surgery, Hospitals of the Pardubice Region - Pardubice hospital, Pardubice, Czech Republic
  • 2Faculty of Health Studies, University of Pardubice, Pardubice, Czech Republic
JAMA Otolaryngol Head Neck Surg. 2021;147(10):915-917. doi:10.1001/jamaoto.2021.2216

In March 2020, the World Health Organization characterized the spread of coronavirus disease (COVID-19) as a pandemic. A lot of nasal swabs were used to diagnose COVID-19 to detect the presence of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) in the upper respiratory tract. We present a case of cerebrospinal fluid (CSF) leak after skull base injury following nasal swab testing for COVID-19 in a patient with a previously intact skull base.

Report of a Case

An otherwise healthy man in his 40s presented for right-sided clear water rhinorrhea in December of 2020. Rhinorrhea originated after nasal swab testing and was mistakenly considered to be allergic rhinitis in the patient. The test was performed by a mobile unit at the patient’s home in March of 2020. The test was indicated because of previous contact with a woman who had a positive COVID-19 test result 5 days earlier. The patient had no symptoms of COVID-19 infection and RNA of SARS-CoV-2 was not detected by polymerase chain reaction (PCR) testing. The patient had no other symptom except persistent unilateral nasal discharge from March to December 2020. During this period he did not report any signs of meningitis. The first examination at an ENT specialist was done in December 2020, 9 months after the first symptom appeared.

Clear nasal secretion medial to the middle turbinate on the right side was noticeable during nasal endoscopy. On computed tomographic (CT) scan there was a defect in the lamina cribrosa on the right side (Figure). A previous brain CT scan from 2011 showed no skull base defect or other pathology. We collected 3 mL of nasal discharge, and analysis showed a high level of the beta-trace-protein in the nasal secretion (23.7 mg/L; normal range, <6 mg/L). The patient’s olfaction was normal, with an Odorized Markers Test score of 11 of 12 points.1

Figure.  Computed Tomographic and Clinical Images
Computed Tomographic and Clinical Images

A, Computed tomographic scan of the sagittal plane. The yellow arrowhead points at the defect in cribriform plate on the right side of the nasal cavity. The dashed arrow represents the assumed trajectory of the nasal swab. B, Endoscopic image of the right side of the nasal cavity. The yellow arrowhead points to clear secretion between the middle turbinate (MT) and the septum (S). C, Perioperative endoscopic view of the skull base on the right side of the nasal cavity. The blue arrowhead points at the defect in the cribriform plate. The roof of the ethmoids (E) and canal of the anterior ethmoidal artery (AEA) can be seen in proximity of the defect.

Endonasal endoscopic closure was performed in December of 2020 with antibiotic prophylaxis (ciprofloxacin, 400 mg twice daily) that continued for 7 days postoperatively. The defect in the lamina cribrosa was identified and cleaned from surrounding mucosa. Temporal muscle fascia was used as an underlay graft. Mucosa from the middle turbinate was used as an overlay graft and fixed with fibrin glue.

The patient was dismissed on the second day after surgery, instructed to avoid blowing the nose. No unexpected adverse events were observed in the postoperative period. Three weeks after surgery, no crusting or rhinorrhea was observed on nasal endoscopic findings. The patient reported anosmia when trying to sniff with the right side of the nasal cavity. The score of an Odorized Markers Test was 8 points (hyposmia, testing both sides).


Laboratory diagnosis of COVID-19 is based on detection of SARS-CoV-2 RNA in the upper respiratory tract by real-time reverse transcription-PCR (RT-PCR). Detection of viral antigens is also a method of choice. The gold standard is collection of the specimen from the nasopharynx through transnasal swab testing. From March 2020 to May 2021, more than 25 million tests were performed in the Czech Republic.

Common complications encountered after nasal swab testing included broken and compacted swabs in the nasal cavity and nosebleed. Rarely the epistaxis required nasal packing or surgical cauterization.2

A CSF fistula is a rare but dangerous complication. The iatrogenic CSF leak after nasal swab testing for COVID-19 was reported after trauma to the preexisting skull base erosion.3,4 To our knowledge, there are no reports of CSF leak after nasal swab testing in patients with no preexisting pathology in nasal cavity or skull base.


Complications after nasal swab testing can be expected during the COVID-19 pandemic owing to an increase in nasal swab testing. Every instance of unilateral clear water rhinorrhea that appears after transnasal testing must be considered a potential CSF leak. To our knowledge this is the first case report presenting CSF fistula following the nasal swab testing in a healthy man with no preexisting skull base condition.

Back to top
Article Information

Corresponding Author: Zdeněk Knížek, Clinic of Otorhinolaryngology and Head and Neck Surgery, Hospitals of the Pardubice Region, Pardubice hospital, Pardubice, Czech Republic, Kyjevská 44, Pardubice 53003, (knizekz@seznam.cz).

Published Online: September 9, 2021. doi:10.1001/jamaoto.2021.2216

Conflict of Interest Disclosures: None reported.

Additional Contributions: We thank the patient for granting permission to publish this information.

Vodička  J, Pellant  A, Chrobok  V.  Screening of olfactory function using odourized markers.   Rhinology. 2007;45(2):164-168.PubMedGoogle Scholar
Fabbris  C, Cestaro  W, Menegaldo  A,  et al.  Is oro/nasopharyngeal swab for SARS-CoV-2 detection a safe procedure? complications observed among a case series of 4876 consecutive swabs.   Am J Otolaryngol. 2021;42(1):102758. doi:10.1016/j.amjoto.2020.102758PubMedGoogle Scholar
Rajah  J, Lee  J.  CSF rhinorrhoea post COVID-19 swab: a case report and review of literature.   J Clin Neurosci. 2021;86:6-9. doi:10.1016/j.jocn.2021.01.003PubMedGoogle ScholarCrossref
Sullivan  CB, Schwalje  AT, Jensen  M,  et al.  Cerebrospinal fluid leak after nasal swab testing for coronavirus disease 2019.   JAMA Otolaryngol Head Neck Surg. 2020;146(12):1179-1181. doi:10.1001/jamaoto.2020.3579PubMedGoogle ScholarCrossref