Introduction

The Coronavirus 2019 (Covid-19) caused a pandemic which affected the whole world. Identification and isolation of asymptomatic and symptomatic individuals is crucial in taking the disease under control. Existence of diagnostic tests with high precision is also very important in this task. Taking nasopharyngeal swab samples is one of the frequently used tests accepted by the Centers for Disease Control and Prevention (CDC) [1]. However, complications during nasopharyngeal swab sample procedures have not clearly been documented. In this case presentation, the rhinorrhea of the cerebrospinal fluid (CSF) during the nasopharyngeal swab sampling and its fixation has been explained.

Case Presentation

A 61-year-old male patient came to our hospital with complaints of unilateral transparent nasal discharge increasing while bending down. He was tested for Covid-19 PCR a month ago due to symptoms similar to flu. Shortly after the tests, his complaints about unilateral rhinorrhea have started. The Beta-2 transferrin test applied in order to understand the rhinorrhea etiology came up positive for CSF. No other specialty has been identified in the patient’s history. There was no history of nasal surgery or nasal trauma. The checks for chronic sinusitis and allergic rhinitis were negative. Anterior rhinoscopy and fiber optical nasopharyngoscopy were also normal. In the paranasal computed tomography (CT) opacifications inside the left sphenoid sinus (Fig. 1) were detected. In the magnetic resonance imaging (MRI) cisternography, encephalocele herniated inside the sinus via bone defection on the inferolateral wall of sphenoid sinus. Under the light of these indications, repairment of defects through endoscopic sinus surgery (ESS) was scheduled for our patient. Intracheal fluorescein was given to the patient before the operation. After opening the ethmoid cells, the sphenoid sinus ostium was located and fluorescein was seen inside it. No additional pathology causing rhinorrhea in the cribriform plate, fovea etmoidalis and lateral lamella was detected. Graft prepared from temporal fascia was laid between the defected dura and the bone. CSF rhinorrhea was seen stopped. After layered waterproof repairment by placing middle concha mucosa, the procedure was finalized without any complications. Post-operatively after being monitored for five days in hospital, the patient was given bed rest, antibiotics (ampicillin sulbactam) and anti-diuretic (acetazolamide). No CSF rhinorrhea was detected at endoscopic examination on the 14th day post-operatively. The sphenoid sinus specimens which had been sent for pathological analysis were confirmed encephalocele.

Fig. 1
figure 1

 A, Coronal CT sequence showing on the left sphenoid sinus lateral, dehiscent area related to mid-cranial fossa, and opacification inside the sphenoid sinus are observed (White arrow). B, Axial MRI cisternography showing encephalocele herniating through sphenoid defect into sphenoid sinus with surrounding T2 hyperintensity (CSF) note white arrow in axial denoting temporal horn being drawn into encephalocele. C, Defect after encephalocele excision on left sphenoid sinus lateral wall (black arrow) after sphenoid sinus ostium was expanded

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Discussion

Since the emergence of the Covid-19 pandemic, a significant increase in the use of nasopharyngeal swab samples was observed. Complications such as; epistaxis after taking nasopharyngeal swab sample, swab remaining inside nasal cavity after breaking, and CSF rhinorrhea might be seen rarely during sampling. [2]. The CSF rhinorrhea happened by trauma can cause neurological sequels and vital complications because they have the risk of meningitis. For that reason, they should be repaired urgently as soon as they are diagnosed.

Two cases which have been presented in the literature as related with nasopharyngeal swab samples taken for Covid-19 diagnosis are found to be deriving from sphenoid sinus lateral wall, and indicating similarities with the case presented in our work [3, 4]. There was no CSF leakage, although there was defective area on the skull base due to increased intracranial pressure in paranasal CT taken previously, in the patient in the first study. The rhinorrhea was developed after nasopharyngeal swab sample was taken, encephalocele stretching from right ethmoid roof to sphenoid sinus right lateral wall was detected, and repaired with ESS. In the other study, a 59-year-old male patient was diagnosed with defect at the left sphenoid sinus lateral wall after CSF leakage detected from left nasal passage following nasopharyngeal swab sampling, and was repaired by vascularized nasoseptal flap under ESS. In the other patient presented in the literature, severe pain occurred following nasopharyngeal swab sampling, and rhinorrhea started immediately after sampling [5]. Paranasal CT and MRI indicated defect in cribriform plate combination location, and fovea etmoidalis in the anterior of sphenoid sinus rostrum. They were repaired by graft prepared from middle concha mucosa resected with ESS.

In the case we presented, lack of previous rhinorrhea history and emergence of the complaints of the patient after nasopharyngeal swab sampling could be related with trauma. However, both the localization of the defect and presence of symptoms regarding chronic intracranial pressure increase in patient’s preoperative MRI cisternography, CSF rhinorrhea could be considered as not deriving directly from skull base trauma during nasopharyngeal swab sampling. CSF rhinorrhea could be caused by trauma of the pre-existing encephalocele deriving from sphenoid sinus lateral wall.

Along with increasing vaccination efforts aiming at taking the Covid-19 pandemic, nasopharyngeal swab sampling is still an effective method in diagnosing the illness. At this point, we believe that it is highly important that nasopharyngeal swab sampling should be executed by taking into consideration of anatomical differences and patient-based factors. In order to prevent complications which might derive from nasopharyngeal swab sampling, the patients must be asked whether they had history of base of skull surgery or nasal surgery before testing. We believe that such complications are preventable with appropriate technical and anatomical knowledge.

Conclusions

It is highly important that, in order to avoid complications during nasopharyngeal swab sampling for Covid-19 diagnosis, the medical people should be trained in details, and samples should be taken with correct application of method. Unilateral transparent nasal discharge after nasopharyngeal swab sampling should warn the clinician for possible CSF rhinorrhea.