Conjunctiva-Upper Respiratory Tract Irrigation for Early Diagnosis of Severe Acute Respiratory Syndrome

Abstract

We devised a method for self-obtaining nasopharyngeal specimens. Patients were given detailed written or verbal instructions. Materials included a 5-ml syringe filled with injectable normal saline, a specimen container, and facial tissues. The process involved the application of normal saline eye drops and expectoration of irrigate that ran into the throat.Anatomically, the conjunctival sac is connected to the nasal cavity by the nasolacrimal duct. Contraction of the palpebral fibers of the orbicularis oculi muscles during blinking opens the normally collapsed, elastic, lacrimal sacs, which return to their collapsed state after blinking; secretions are sucked in through the lacrimal cannaliculi and discharged into the nasolacrimal ducts (1, 2). The mucosal folds in the nasolacrimal ducts ensure one-way traffic to the nose. The lipid content of the meibomian gland secretions makes the lid margins water repellant. Unless too much is applied, the irrigate does not spill from the conjunctival sacs. These anatomical features are exploited in the technique of conjunctiva-upper respiratory tract irrigation (CURTI). With this technique, patients self-apply 1 drop of normal saline per eye at a time. They are asked to blink repeatedly, tilt their heads backward, and sniff to facilitate the drainage of fluid into the nasopharynx. Patients must not swallow the liquid; instead, it should be spat into a specimen container. Patients are told that there is a time lag of up to a minute or two before the fluid begins to run into the throat, and that after one stops applying the eye drops, fluid will continue to run into the throat for a minute or two. Fluid that drains into the throat even after stopping the eye drops should be collected. Specimens reported to be salty were deemed adequate.We tested CURTI with four patients with confirmed severe acute respiratory syndrome (SARS) soon after admission. By using an immunofluorescence assay for SARS coronavirus (4), all patients were found to have seroconverted 13 to 21 days after admission (titer rose from Ͻ25 to 200 to 1,600). When real-time PCR (3) and primers Cor-1 and Cor-2 (5) were used, two of the four patients tested positive for the CURTI specimens. By comparison, none of the nose/throat swab (NTS) and stool specimens were positive.Although we cannot compare the sensitivity of CURTI with that of nasopharyngeal aspiration (NPA) since the use of NPA was rejected in our hospital, we found CURTI to be more sensitive than NTS in the four patients we studied. Analysis of data (ongoing) revealed an unsatisfactory sensitivity of 60% with NTS in confirmed cases of SARS (based on seroconversion). CURTI, therefore, has a potential sensitivity in excess of 60%.CURTI is simple and well tolerated, as shown by the results with our volunteers. It compares favorably with NPA and NTS in terms of patient comfort and staff safety because it does not provoke sneezing. The CURTI process irrigates the nasopharynx, whereas saliva comes mostly from the three pairs of salivary glands which drain into...

Clinical picture, diagnosis, treatment and outcome of severe acute respiratory syndrome (SARS) in children

“…To obviate the need for the protection of healthcare workers, an ingenious method for self-obtaining nasopharyngeal specimens through conjunctiva-upper respiratory tract irrigation (CURTI) has been described as an alternative. 64…”

Ocular Pathology

“…87 In one of the patients with encephalitis, optic disc blurring with bilateral abducens nerve palsies has been reported. 89,90 Because most of the routine ophthalmic examinations such as direct ophthalmoscopy and slit-lamp examination are performed in a setting that has close doctor-patient contact, so ophthalmologists may be particularly susceptible to the infection. However, foci responsible for this syndrome have been associated with the brainstem and dentate nucleus of the cerebellum, and an autoimmune pathomechanism has been suggested.…”

Severe Acute Respiratory Syndrome Coronavirus (SARS-CoV)

“…WHO network laboratories made available various primers and protocols for these tests (http://www.who.int/csr/ sars/primers/en/index.html). Specimens from the upper respiratory tract, sputum, blood, stool, and urine have all yielded viral nucleic acid at various stages of the illness (Grant et al, 2003;Ng et al, 2003;Tong et al, 2003;Chan et al, 2004d;Hung et al, 2004;Ng et al, 2004). Viral load data generated from qRT-PCR were later shown to correlate with outcome (Chu et al, 2004c;Hung et al, 2004).…”