The history should focus on when the symptoms started and the physical exam should be accompanied by selective imaging tests. In children the typical signs of a CNS abscess are not always present and hence clinical suspicion must be high.

Most patients have a low grade fever and leukocytosis.
Patients who develop orbital cellulitis will present with the following clinical features:

• Eyelid swelling
• Conjunctival chemosis
• Visual loss
• Tenderness around the eye
• Decreased ocular motility
• Diplopia
• Purulent material
• Proptosis which may not be prominent in cases of preseptal cellulitis.
• Because of the inability to close the eyelids, these patients may also develop corneal infections from exposure keratopathy

• In children, proptosis and ophthalmoplegia are common features, while chemosis and diminished visual acuity are less frequently seen in both children and adults.
• In advanced cases with optic nerve involvement, there is usually disc edema or neuritis which can rapidly progress leading to blindness.
• In severe cases with extension of the infection into the cavernous sinus, there may be involvement of cranial nerves 3, 5 and 6.
• When a patient presents with a red and swollen eye, other diagnosis to be considered include an allergic reaction to a medication, edema from hypoproteinemia, trauma, blood coagulation disorder, retinoblastoma, orbital pseudotumor or metastatic carcinoma. If the process is bilateral, one needs to rule out exophthalmos secondary to thyroid related orbitopathy.

• Fever

  Fever and systemic signs may be present. No proptosis, no ophthalmolplegia, normal vision Diagnosis : Usually clinical findings are enough. If unable to inspect the eye, should get CT scan. [pedclerk.bsd.uchicago.edu]

  A 30-day-old, previously healthy, near-term neonate presented with fever and swelling of the left eye. Orbital cellulitis of the left eye was diagnosed by computed tomography. [ncbi.nlm.nih.gov]

  […] blood supply is from the facial/ophthalmic veins) clinical presentation is due to the venous obstruction as well as impairment of the cranial nerves that are run through/along the cavernous sinus Headache is the most common symptom and usually precedes fevers [errolozdalga.com]

  Group V - Cavernous sinus thrombosis  Development of bilateral ocular signs is the classic feature of patients belonging to this group  Manifest with fever, headache, photophobia, proptosis, ophthalmoplegia and loss of vision  Cranial nerve palsies [slideshare.net]

• Malaise

  […] eye Orbital cellulitis: acute sinusitis (especially ethmoid sinusitis) trauma including orbital fracture dacryocystitis preseptal cellulitis dental abscess Symptoms Preseptal cellulitis: acute onset of swelling, redness and tenderness of lids fever malaise [college-optometrists.org]

  […] reddish or purplish in color Restricted eye movements Eye pain, especially with movement Eye burning, itching and discharge Swelling of the eyelids Decreased vision as a result of swollen eyelid Bulging eyes (forward displacement of the eye) General malaise [diagnose-me.com]

  Severe malaise. Differential diagnosis [ 2, 11 ] Orbital/preseptal cellulitis. Necrotising fasciitis. Chalazion. Allergic lid swelling. Severe viral conjunctivitis. [patient.info]

  Patient had malaise; however, there was no history of maxillofacial infections, fever, chills, trauma, or recent surgeries. There was no history of epiphora. [nature.com]

  […] greater  Painful swelling of upper and lower lids  Eyelid appears shiny and is red or purple in color  Infant or child is acutely ill or toxic  Eye pain especially with movement  Decreased vision  Eye bulging  Swelling of the eyelids  General malaise [slideshare.net]

• Severe Pain

  The condition is characterized by infection and swelling of the soft tissues lining the eye socket, pushing the eye ball outwards and causing severe pain, redness, discharge of pus and some degree of blurred vision. [jmm.microbiologyresearch.org]

• Ecchymosis

  […] orbital tumor Synonyms: tumor of the orbit Translation: Augenhöhlentumor Orbitatumor periorbital cellulitis Synonyms: preseptal cellulitis Translation: periorbitale Cellulitis periorbitale Zellulitis präseptale Cellulitis präseptale Zellulitis periorbital ecchymosis [zeitzfrankozeitz.de]

• Nausea

  Patients with lethargy, nausea, vomiting, headache, seizures or cranial nerve deficits also need more extensive in hospital work up. Admitted patients usually require IV antibiotics for 5-10 days. [symptoma.com]

  […] recent ocular surgery, pertinent medical conditions, medications currently used, as well as the presence of diabetes mellitus and the immune status of the patient.Specific questions regarding any change in mental status, pain with neck movement, or nausea [eyewiki.aao.org]

  These patients may have nausea, vomiting along with signs of nervous system involvement which could also be due to septicemia. [intechopen.com]

• Abdominal Pain

  Haug Browse recently published Learning/CME Learning/CME View all learning/CME CME Partial Oral versus Intravenous Antibiotic Treatment of Endocarditis Case 4-2019: An 18-Year-Old Man with Abdominal Pain and Hematochezia Bridging the Gap Challenge Yourself [nejm.org]

• Skin Lesion

  His visual acuity declined and the right side of his forehead developed a necrotic skin lesion with a purulent discharge. CT of the orbits suggested orbital cellulitis with subperiosteal abscess. [ncbi.nlm.nih.gov]

  Strep pyogenes and Staph aureus are likely if there is a contiguous skin lesion. Rarely Haemophilus influenzae may be the cause particularly in children under five who are not fully immunised. [rch.org.au]

  lesion(s) Orbital cellulitis: cavernous sinus thrombosis mucormycosis (fungal infection) sarcoidosis dysthyroid exophthalmos neoplasia with inflammation Management by optometrist Practitioners should recognise their limitations and where necessary seek [college-optometrists.org]

  External photograph of a 19-years-old male who presented with 3 day history of left-sided facial erythema, swelling, conjunctival chemosis, proptosis and eruptive skin lesions. [intechopen.com]

• Pruritus

  However, the presence of pruritus and the absence of tenderness are helpful distinguishing characteristics. Pathogenesis The anatomy of the eye is important for understanding its susceptibility to spread of infection from contiguous structures. [pedsinreview.aappublications.org]

• Blister

  They can also lead to impetigo, which is a highly contagious skin infection that causes minor blisters and crusting. [healthline.com]

• Eye Pain

  A 65-year-old female patient presented with eye pain, swelling and blurred vision in the left eye. Routine biochemistry and microbiological analyzes were conducted. [ncbi.nlm.nih.gov]

  Signs and symptoms include swelling and pain of the eyelids, pain in the eye, painful eye movements, decreased vision, and fever. [icd9data.com]

• Diplopia

  Abstract The authors describe the case of a 48 years old woman who presented with a one week history of a painful, swollen left eye with proptosis and diplopia. [ncbi.nlm.nih.gov]

• Strabismus

  To our knowledge, this is the first case of bilateral orbital cellulitis following strabismus surgery. [ncbi.nlm.nih.gov]

  Barone SR, Aiuto CP (1997) Journal of Paediatric Ophthalmology and Strabismus. 34: 293–296 Google Scholar 3. [springerlink.com]

• Periorbital Edema

  Periorbital edema and chemosis result from occlusion of the ophthalmic veins. [errolozdalga.com]

  Clinical examination was significant for decreased vision in the affected orbit of 20/50, a trace RAPD OS, elevated IOP of 30 OS, proptosis and grossly decreased motility with diplopia, periorbital edema and chemosis. [ncbi.nlm.nih.gov]

  All 6 cases presented with headache, fever, ocular motility deficit, periorbital edema, and proptosis. The primary source of infection included sinusitis (n = 4) and bacteremia (n = 2). [doi.org]

• Conjunctival Injection

  However, the incidence rates of ptosis, conjunctival injection, and chemosis exhibited no differences between the diseases. [ncbi.nlm.nih.gov]

  […] chemosis -not an "orbital process" clinical features of orbital disease -proptosis, conjunctival injection, conjunctival chemosis, motility limitation and visual changes extension from peri-orbital structures -paranasal sinuses, face, eyelids, dacrocystitis [quizlet.com]

  There is usually no or minimal conjunctival injection. Often, an external cause is observable in preseptal cellulitis. Eyelid appearance immediately after incision and drainage. [healio.com]

  With lid retraction, she had marked bulbar and palpebral conjunctival injection, photophobia, painful extraocular movements and proptosis. She had some limitations to inward gaze but it was difficult to assess because of pain. [pediatriceducation.org]

• Facial Pain

  Jones, Sinogenic Facial Pain: Diagnosis and Management, Otolaryngologic Clinics of North America, 10.1016/j.otc.2005.07.005, 38, 6, (1311-1325), (2005). Guy J. Ben Simon, Steven Bush, Dinesh Selva and Alan A. [doi.org]

• Confusion

  In the early stages of the disease it is easy to confuse orbital cellulitis for its less serious cousin, peri-orbital cellulitis. [dontforgetthebubbles.com]

  You feel confused or more sleepy than usual. Your forehead is numb. You have a stiff neck and vomiting. You are seeing double or your vision is blurred. You notice vision loss. You cannot move your eye. [drugs.com]

  It should not be confused with periorbital cellulitis, which refers to cellulitis anterior to the septum. Without proper treatment, orbital cellulitis may lead to serious consequences, including permanent loss of vision or even death. [en.wikipedia.org]

  Confusion still exists between the diagnosis of this serious condition and that of pre-septal cellulitis. [ispub.com]

• Seizure

  Patients with lethargy, nausea, vomiting, headache, seizures or cranial nerve deficits also need more extensive in hospital work up. Admitted patients usually require IV antibiotics for 5-10 days. [symptoma.com]

  Patient with intracranial abscess may be asymptomatic or present with nausea, vomiting, seizures and change of their mental status. [ 27 ] Among other signs, neurological signs of intracranial abscess may include fever or altered mental status. [intechopen.com]

When orbital cellulitis is suspected, ultrasound is often the first test of choice. Even though Ultrasound can detect abscess of the anterior orbit or medial wall, it is not very sensitive and very operator dependent. Thus, most healthcare providers order a CT scan. CT scan should be performed on any patient whose vision or range of motion of the globe cannot be properly assessed. In addition, CT should be performed when there are visual deficits. Ct scan can identify abscesses, inflammatory changes and even provide the location with great accuracy. CT scan can also influence the course of treatment. MRI has been used to assess patients with orbital cellulitis but it is more expensive and does not offer any more diagnostic information compared to a CT scan.[6]

• Plain x-rays of the sinuses are not sensitive and of little use.
• The patient must have a thorough eye exam including visual acuity which must be checked and recorded in each patient.
• Routine blood work includes CBC and coagulation.
• Blood cultures.
• If there is purulent discharge from the site of infection, cultures should be obtained as they may help guide therapy.

• Neutrophilia

  There was neutrophilia, and the swab culture was sterile similar to other studies. [13], [23] However, it has been reported that blood and skin microscopy, culture, and sensitivity, though important, usually yields no growth; rather, the swabs taken endoscopically [nigerianjournalofophthalmology.com]

• Leukocytosis

  […] abscess formation increases the severity of these findings and results in decreased visual acuity · Proptosis may not be grossly apparent and should be measured (e.g., with an exophthalmometer); a difference of 2 mm or more is significant · Fever and leukocytosis [errolozdalga.com]

  FBC frequently shows a leukocytosis (>15 x 10 9 ) but blood cultures are frequently negative in adults with either condition. Any discharge from skin breaks should be swabbed and sent to microbiology. [patient.info]

  […] surrounding fat, tendon, and myotendinous junction  Presents as orbital and periorbital pain, ocular movement impairment, diplopia, proptosis, swollen eyelids, and conjunctival hyperemia  Orbital cellulitis, which is commonly accompanied by fever, leukocytosis [slideshare.net]

  Pertinent findings include leukocytosis and fever. In this patient, she had already been treated with a four day course of antibiotics which explains her afebrile state as well as her normal WBC count. [webeye.ophth.uiowa.edu]

  Though a history of constitutional symptoms and vital signs should heighten clinical suspicion, nothing replaces a thorough physical exam. [3] Blood work such as a complete blood count (CBC) may show leukocytosis with a neutrophil predominance, though [ncbi.nlm.nih.gov]

Once the diagnosis of orbital cellulitis is made, the treatment depends on the severity of the condition, patient’s comorbid disorders, age, ability to take oral medications, compliance and presence of complications. Orbital cellulitis is managed as an inpatient initially with parenteral antibiotics. Both the otolaryngologist and ophthalmologist should be consulted for all cases of orbital cellulitis [7][8].

All patients who present with diplopia, eyelid edema, decreased visual acuity, abnormal light reflex, proptosis and ophthalmoplegia need admission. In addition, if the patient appears toxic and an incomplete eye exam is not possible admission is required. Patients with lethargy, nausea, vomiting, headache, seizures or cranial nerve deficits also need more extensive in hospital work up [9][10].

Admitted patients usually require IV antibiotics for 5-10 days. Initially broad spectrum antibiotics are started to cover both gram positive and negative organisms. Once culture results are available, the therapy can be tailored to the organism. It is recommended that the selected antibiotic cover Staphylococcus, Streptococci and Haemophilus species. Initially the broad spectrum of antibiotics should cover methicillin resistant staphylococcus. Other measures of treatment include control of fever and warm compresses. If there is no improvement in 24-48 hours after initiating antibiotics, one should panculture the patient and consult with an ID expert.

In general, cultures from the nose, throat and conjunctiva do not represent the pathogen cultures from the abscess. Blood cultures are often negative and not helpful. The antibiotics recommended are third generation cephalosporins and the quinolones. Once the patient has stabilized and has no fever or signs of an infection, he/she can be discharge home on oral antibiotics. If the patient fails to improve within 24-36 hours after initiating IV antibiotics, a CT scan of the brain should be obtained and consideration should be given to an orbital or subperiosteal abscess. The duration of antibiotics in outpatients may vary from 3 -30 days, depending on symptoms and improvement.

Surgery

The decision to undertake surgery in patients with orbital abscess depends on response to therapy, the sinus involved, type of microorganism, visual status, location of orbital abscess and any potential intracranial complications. In general surgery to drain an abscess is usually done when the optic nerve or retinal function is compromised.
When an abscess is present and compressing on a vital structure, emergency drainage may be necessary, especially in patients with compromised vision. Surgery should also be considered when fever does not abate within 24-48 hours after starting IV antibiotics. Surgery should also be considered when there is progressive deterioration of vision despite continuing antibiotics. Urgent drainage is often recommended for large superior or inferior orbital abscess and for patients with CNS complications. In addition, any dental abscess also needs surgical drainage. Patients who are not improving should always be suspected of having an abscess and a CT scan is recommended to follow the course of treatment. Anytime a sinus infection has extended into the orbit, urgent drainage is required. In some cases, even the CT scan may not be accurate in assessing the clinical course in some patients and hence surgical judgment is required.

Overall, orbital cellulitis can be treated with minimal morbidity and mortality.
With improve diagnosis and prompt medical diagnosis, intracranial complications following orbital cellulitis are now rare. Most intracranial complications occurrin the frontal lobe, subdural or epidural compartment. Sinus infections are generally the most common causes of intracranial abscess. The most common is the frontal sinus followed by ethmoid and maxillary sinuses. Complications of orbital cellulitis include subperiosteal or orbital abscess, vision loss, cavernous sinus thrombosis, and intracranial infection.
Death is very rare with orbital cellulitis today. When the diagnosis is made promptly and antibiotics are taken, the cure rates are high. However, if the diagnosis is missed or there is a delay in treatment, orbital abscess can result which carries a high morbidity. In spite of systemic antibiotics and surgical intervention, orbital abscess is a serious disorder with devastating outcome. Statistical evidence reports visual loss in 7-24 percent of patients. Visual loss may be due to central retinal artery occlusion, optic nerve atrophy, or exposure keratopathy which has led to development of corneal ulcers. Other complications of orbital cellulitis include cavernous sinus thrombosis, meningitis and cranial nerve palsies. Any delay in treatment is also associated with a negative outcome. Other reported complications include endophthalmitis, which usually requires evisceration or enucleation.

In children the most common predisposing factor for orbital cellulitis is sinus infection. Others may develop orbital cellulitis as a result of trauma to the eyelids or presence of dental abscess.
Other rare causes of orbital cellulitis include :

• Periocular surgery
• Endoophthalmitis
• Dacrocytitis

A wide range of organisms can cause orbital cellulitis. The most common include Staphylococcus aureus, Staphylococcus epidermidis, Streptococci, Haemophilus influenzae, E.coli, diphtheroids and anaerobes. However, the most common organism in most cases is Staphylococcus aureus. From published reports, children tend to have a simple infection caused by a single aerobe organism. Older children and adults tend to develop more complex infections caused by multiple bacteria that often tend to be resistant to antibiotics.

In children orbital cellulitis is thought to result because of incomplete development of immunity, resulting in sinus disease. The majority of children with orbital cellulitis are known to have sinusitis of the ethmoidal and maxillary sinuses.

In adults, frontal sinus disease is more common. Other sources of infection include retained foreign body. Dacryocystitis, infected malignancy, panophthalmitis, fungal infection (mucormycosis) and herpes zoster.

In diabetic patients with orbital cellulitis, a fungal cause must be ruled out. The two most common fungus associated with orbital cellulitis in diabetics include Aspergillosis and Mucormycosis. The latter seems to be more common in diabetic ketoacidosis. The onset of Mucromycosis is very rapid whereas Aspergillosis may be a gradual infection. Histology of tissues in cases of Mucromycosis will reveal thrombosed vessels with ischemic necrosis.

Orbital cellulitis is not a common disorder. The incidence is reported to range from 0.5 to 4% in tertiary care centers. Most new series do not report a high number of orbital abscesses cases and only a few reports of intracranial complications. The complication rates of orbital cellulitis do vary in the literature because of various inclusion and exclusion criteria. In the present era, the incidence of CNS complications in patients with orbital cellulitis has been reported to be less than 2%. The main reason why complications of orbital cellulitis have decreased is because of awareness, earlier diagnosis and more effective antibiotics. Orbital cellulitis can occur at all ages and in both genders. The infection appears to be slightly more common in diabetics and immunocompromised individuals.

Orbital cellulitis can occur in several ways. If there is trauma to the eye, then foreign bodies and microorganism can be introduced into the ocular tissues and initiate an infection. In some cases, there may be hematogenous transfer of bacteria from a distant site that can induce the infection. [5] However, in the majority of cases, the infection is from the adjacent sinuses. When a sinus infection occurs, it can easily extend across the thin orbital wall into the eye tissues and initiate an infection. Once orbital cellulitis occurs, the infection can even be transmitted to the CNS via the valveless veins that interconnect the orbit with the sinuses, eyelid and cavernous sinus.
The mechanical pressure of the edema and inflammatory process (abscess) on the optic nerve and retinal vessels is also responsible for the optic nerve atrophy. When the retinal vessels are compressed as well as the presence of inflammation, it can result in infarction of the sclera, optic nerve, retina and choroid. A rare complication of orbital cellulitis is glaucoma that can present with diminished vision, reduce visual field and an enlarged blind spot.

Orbital cellulitis can not be completely prevented but one can reduce the morbidity of the disorder by seeking immediate attention. Any individual with redness, visual loss and fever should be asked to seek immediate attention from a healthcare professional. Diabetics should ensure that their blood sugars are well controlled and avoid ketoacidosis as this makes them prone to mucormycosis. When the diagnosis of orbital cellulitis is made close followup and compliance with antibiotics is essential. Any patient who presents with visual difficulty, pain or redness around the eye should have the visual acuity measured and have a thorough eye exam.

Orbital cellulitis is a rare infectious disorder of the eye which typically presents with pain, decreased visual acuity, diminished motility of the ocular muscles and prominent proptosis. In the present era of healthcare, complete loss of vision following orbital cellulitis is rare because of improved diagnosis tests and effective antibiotics. In the majority of cases in children there is a prior history of an upper respiratory tract infection before the onset of orbital cellulitis. While most cases of orbital cellulitis can be readily treated, however, whenthe diagnosis is missed, it can lead to a fatal outcome because of extension of the infection to the cavernous sinus and CNS. Further loss of vision can be permanent in some people. Since the widespread use of antibiotics, complications of orbital cellulitis are rarely seen today [1][2][3][4].

Orbital cellulitis is a serious infection of the eye. It typically occurs after a sinus infection  and can present with redness, pain, drainage and poor vision. One should seek immediate medical attention if these symptoms occur. If the treatment is delayed, the eye infection can easily reach the brain tissues and induce seizures, nausea, vomiting and even death. The diagnosis of orbital cellulitis is based on the clinical presentation and imaging studies like the CT scan. The infection is readily treated with antibiotics, but in some cases, surgery may be required to drain the pus. The prgnosis for most patients with orbital cellulitis is good.

1. Pakdaman MN, Sepahdari AR, Elkhamary SM. Orbital inflammatory disease: Pictorial review and differential diagnosis. World J Radiol. 2014 Apr 28;6(4):106-15.
2. Allan K, Atkinson H, Agada F. Posterior orbital cellulitis: case report and literature review. J Craniofac Surg. 2013 Sep;24(5):1706-10
3. Yang E, Fisher M, Servat J, Levin F. Neonatal orbital abscess after sinus surgery: case report and brief review. Orbit. 2013 Oct;32(5):312-4.
4. Peña MT, Preciado D, Orestes M, Choi S. Orbital complications of acute sinusitis: changes in the post-pneumococcal vaccine era. JAMA Otolaryngol Head Neck Surg. 2013 Mar;139(3):223-7
5. Yan W, Chakrabarti R, Choong J, Hardy T. Orbital Cellulitis of Odontogenic Origin. Orbit. 2015 May 8:1-3.
6. Hegde AN, Mohan S, Pandya A, Shah GV. Imaging in infections of the head and neck. Neuroimaging Clin N Am. 2012 Nov;22(4):727-54.
7. Chadha NK. An evidence-based staging system for orbital infections from acute rhinosinusitis. Laryngoscope. 2012 Dec;122 Suppl 4:S95-6.
8. Ozkurt FE, Ozkurt ZG, Gul A, Akdag M, Sengul E, Yilmaz B, Yuksel H, Meric F. Managment of orbital complications of sinusitis. Arq Bras Oftalmol. 2014 Oct;77(5):293-296.
9. Fanella S, Singer A, Embree J. Presentation and management of pediatric orbital cellulitis. Can J Infect Dis Med Microbiol. 2011 Fall;22(3):97-100.
10. DeCroos FC, Liao JC, Ramey NA, Li I Management of odontogenic orbital cellulitis. J Med Life. 2011 Aug 15;4(3):314-7.