After the maxillary sinus, the ethmoid sinus is most commonly affected by infectious pathogens (including bacteria but also viruses and fungi), but it is not uncommon for more than one sinus to be involved [1] [2]. The ethmoid sinus lines the medial wall of the orbit and drains into the middle nasal meatus, which is why typical features of sinusitis - nasal obstruction, rhinorrhea (either serous or purulent), malaise and fever in more severe cases - are often present in patients suffering from ethmoid sinusitis [1] [3]. In many individuals, a preexisting infection of the upper respiratory tract is frequently reported, with symptoms of cough, a sore throat, rhinorrhea and a posterior pharyngeal drip [4]. Having in mind the anatomical proximity of the ethmoid sinus to the eye apparatus, the distinguishing feature of this condition is the concomitant presence of pain between the orbits (or behind the eyes), as well as swelling and tenderness in that area [1] [4]. Headaches are also a common manifestation of sinusitis. Symptoms may last from days to weeks, or even months, depending on the type of sinusitis and is an important clinical finding that can determine the course of treatment. Based on the duration of symptoms, acute (< 30 days), subacute (30-90 days) chronic (> 90 days) or recurrent (multiple episodes during the year) forms of sinusitis are described [1] [4]. Although more severe complications of sinusitis are rare, most notable in terms of ethmoid sinusitis are preseptal or orbital cellulitis, osteomyelitis, subperiosteal orbital abscess and dissemination of microorganisms into the central nervous system (CNS), as well as pseudodacryocystitis and nasolacrimal duct obstruction [4] [5].

• Low Fever

  Symptoms of a cold (runny nose and low fever) often give way to pain and pressure in the sinuses, which are usually the first signs of sinusitis. [humanillnesses.com]

• Pseudotumor

  Rarely, it may be due to an inflammatory pseudotumor. Appropriate management is required to avoid complications from the postseptal cellulitis or from the primary process. [em-consulte.com]

• Hyposmia

  […] sinusitis cause similar symptoms, including Yellow or green pus discharged from the nose Pressure and pain in the face Congestion and blockage in the nose Tenderness (pain when touched) and swelling over the affected sinus Reduced ability to smell (hyposmia [merckmanuals.com]

  Box 2: Symptoms Associated with the Diagnosis of Chronic Sinusitis Facial pain or pressure Facial congestion or fullness Nasal obstruction or blockage Nasal discharge, purulence, or postnasal drip Hyposmia or anosmia Headache Fever Halitosis Fatigue Dental [clevelandclinicmeded.com]

• Anosmia

  When she continued to complain of progressive headaches, right-sided epiphora, and anosmia, limited computed tomography (CT) of the paranasal sinuses was obtained (figure 1). [go.galegroup.com]

  Box 2: Symptoms Associated with the Diagnosis of Chronic Sinusitis Facial pain or pressure Facial congestion or fullness Nasal obstruction or blockage Nasal discharge, purulence, or postnasal drip Hyposmia or anosmia Headache Fever Halitosis Fatigue Dental [clevelandclinicmeded.com]

• Skin Lesion

  Preseptal cellulitis is more common and may be secondary to mucosal or skin lesions: viral (zona), bacterial (impetigo, erysipele, secondary infection after trauma), toxic (insect bite), post-URTI (sinusitis), ophthalmologic lesion (conjunctivitis, dacryocystitis [em-consulte.com]

• Diplopia

  Diplopia can occur if an extraocular muscle, usually the medial rectus, is injured. Atrophic rhinitis has also been reported. [19] More worrisome are the rare, but unfortunate, reports of blindness due to resection of the optic nerve. [emedicine.medscape.com]

  Sphenoid and posterior ethmoid mucoceles are less frequent and may present with orbital involvement resulting in decreased vision, exophthalmos, diplopia or with the superior orbital fissure syndrome consisting of ocular palsies and decreased forehead [skullbaseinstitute.com]

  Orbital floor repair may be helpful in cases with diplopia, severe cosmetic deformity or those with little improvement following endoscopic surgery. 3 Most certainly an acquired condition, SSS should be distinguished from maxillary sinus hypoplasia, which [appliedradiology.com]

• Unilateral Proptosis

  This article presents a case of bilateral ethmoid sinusitis with unilateral proptosis as a presenting sign of an unsuspected prostate carcinoma. A 59-year-old Hispanic male presented to his primary care physician with nasal congestion and rhinitis. [ncbi.nlm.nih.gov]

  proptosis as an initial manifestation of metastatic prostate carcinoma. ( 7861473 ) Fortson J.K....Moseley D.L. 1994 15 Radiological case of the month. [malacards.org]

• Retroorbital Pain

  Having in mind its anatomical location, eye-related symptoms such as retroorbital pain and swelling are used as a distinguishing feature. [symptoma.com]

• Scotoma

  ( 15547805 ) Busaba N.Y....Salman S.D. 2004 12 Peripheral scotoma associated with chronic ethmoidal sinusitis. [malacards.org]

• Frontal Headache

  Discriminatory clinical features include: pain between the eyes frontal headaches Specific treatment is rarely required. The ethmoiditis usually resolves with that of the acute infection. Links: sinusitis treatment of acute sinusitis [gpnotebook.co.uk]

  Maxillary sinusitis may cause pain in the maxillary area of the face, toothache, and frontal headache. Frontal sinusitis causes frontal pain and headache. Ethmoid sinusitis causes pain behind the eyes and frontal headache. [webhealthcentre.com]

  Frontal headaches and purulent nasal drainage have been present intermittently for years. He received multiple courses of oral antibiotics, nasal steroids, and decongestants, with only temporary relief. [aafp.org]

  Osteoma in frontal sinus Osteoma This is a patient who had been having brain MRI for the past 1,5 yrs for frontal headaches. On the MRI (not shown) it looked as if the patient had a little mucosal disease of the frontal sinus. [radiologyassistant.nl]

  Look for: Suspicion of intracranial spread - severe frontal headache, frontal swelling, symptoms or signs of meningitis or focal neurological signs. Suspicion of spread to the orbit - see separate article Orbital and Preseptal Cellulitis. [patient.info]

• Generalized Seizure

  seizure and syndrome of inappropriate antidiuretic hormone secretion: a case report and review of literature. ( 19027514 ) Ma A.T....Lei K.I. 2009 7 Malignant ethmoid sinus tumor masquerading as chronic ethmoid sinusitis. ( 17240703 ) Wright B.E....Osborne [malacards.org]

A meticulous patient history and a thorough physical examination are mandatory steps in achieving a diagnosis of ethmoid sinusitis, principally because clinical criteria are most important when it comes to infection of the paranasal sinuses [1] [2] [4] [6]. Identifying the onset and type of symptoms is detrimental in assessing which sinus is affected, although signs of rhinorrhea, cough, pain and headaches are sufficient to make a presumptive diagnosis of a paranasal infection. Physical findings include dullness (or absence) of light on transillumination exam, whereas detection of serous or mucopurulent discharge is also a notable observation [1] [2]. Clinical suspicion should be supported by imaging studies, which are necessary to confirm ethmoid sinusitis, with plain radiography often employed as the initial method. The occipitomental view is favored for visualization of the ethmoid cells, and an air-fluid level is considered as a diagnostic hallmark [3] [4]. Computed tomography (CT), however, is superior compared to plain X-rays, and is recommended whenever possible [3] [4] [6]. A detailed microbiological investigation is also a mandatory step in the workup. Cultivation of secretions obtained through nasal swabs is detrimental in confirming bacterial etiology, causative agents predominantly being haemophilus influenza, streptococcus pneumoniae, and gram-negative bacilli [7]. On the other hand, rhinovirus, influenza virus, and parainfluenza virus are notable viral agents [4].

• Chlamydia Trachomatis

  No anaerobes, viruses, or Chlamydia trachomatis organisms were identified. Results of this study showed organism isolation frequencies different from those found in other studies of chronic sinusitis reported in the literature. [ncbi.nlm.nih.gov]

1. Porter RS, Kaplan JL. Merck Manual of Diagnosis and Therapy. 19th Edition. Merck Sharp & Dohme Corp. Whitehouse Station, N.J; 2011
2. Longo DL, Fauci AS, Kasper DL, Hauser SL, Jameson J, Loscalzo J. eds. Harrison's Principles of Internal Medicine, 18e. New York, NY: McGraw-Hill; 2012.
3. Mandell GL, Bennett JE, Dolin R. Mandel, Douglas and Bennett's Principles and Practice of Infectious Diseases. 8th ed. Philadelphia, Pennsylvania: Churchill Livingstone; 2015.
4. Masood A, Moumoulidis I, Panesar J. Acute rhinosinusitis in adults: an update on current management. Postgraduate Medical Journal. 2007;83(980):402-408.
5. Yazici B, Yazici Z. Pseudodacryocystitis and nasolacrimal duct obstruction secondary to ethmoiditis. Ophthal Plast Reconstr Surg. 2010;26(5):381-383.
6. Crovetto-Martínez R, Martin-Arregui FJ, Zabala-López-de-Maturana A, Tudela-Cabello K, Crovetto-de la Torre MA. Frequency of the odontogenic maxillary sinusitis extended to the anterior ethmoid sinus and response to surgical treatment. Med Oral Patol Oral Cir Bucal. 2014;19(4):e409-e413.
7. Brook I. Bacteriology of Acute and Chronic Ethmoid Sinusitis. J Clin Microbiol. 2005;43(7):3479-3480.