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{{Orbital cellulitis}}
{{Orbital cellulitis}}
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==Overview==
==Overview==
Orbital cellulitis occurs secondary to [[microbial]] infiltration of the deep [[soft tissue]] cells surrounding the eye, [[posterior]] to the [[Orbital septum|orbital septum]]. The infiltration can occur by means of extension of an adjacent [[infection]] (e.g., [[Sinusitis|rhinosinusitis]]), by direct [[inoculation]] through [[trauma|traumatic]] or [[Iatrogenesis|iatrogenic]] pathways, or by hematogenous spread from a distant infected site. Regardless of the mode of infiltration of the retroseptal [[Orbit (anatomy)|orbital space]], [[Orbital cellulitis history and symptoms|symptoms]] may arise due to the [[Immune system|immune system]] triggering a regional [[Inflammation|acute inflammatory response]].<ref name="pmid15318671">{{cite journal| author=Hasanee K, Sharma S| title=Ophthaproblem. Orbital cellulitis. | journal=Can Fam Physician | year= 2004 | volume= 50 | issue=  | pages= 359, 365, 367 | pmid=15318671 | doi= | pmc=2214559 | url=http://www.ncbi.nlm.nih.gov/entrez/eutils/elink.fcgi?dbfrom=pubmed&tool=sumsearch.org/cite&retmode=ref&cmd=prlinks&id=15318671  }} </ref><ref name="pmid22346113">{{cite journal| author=Chaudhry IA, Al-Rashed W, Arat YO| title=The hot orbit: orbital cellulitis. | journal=Middle East Afr J Ophthalmol | year= 2012 | volume= 19 | issue= 1 | pages= 34-42 | pmid=22346113 | doi=10.4103/0974-9233.92114 | pmc=3277022 | url=http://www.ncbi.nlm.nih.gov/entrez/eutils/elink.fcgi?dbfrom=pubmed&tool=sumsearch.org/cite&retmode=ref&cmd=prlinks&id=22346113  }} </ref><ref name="pmid23107426">{{cite journal| author=Turvey TA, Golden BA| title=Orbital anatomy for the surgeon. | journal=Oral Maxillofac Surg Clin North Am | year= 2012 | volume= 24 | issue= 4 | pages= 525-36 | pmid=23107426 | doi=10.1016/j.coms.2012.08.003 | pmc=3566239 | url=http://www.ncbi.nlm.nih.gov/entrez/eutils/elink.fcgi?dbfrom=pubmed&tool=sumsearch.org/cite&retmode=ref&cmd=prlinks&id=23107426  }} </ref><ref name="acute-inflammatory-response"> U.S. National Library of Medicine Medlineplus(2014) https://medlineplus.gov/ency/article/000821.htm</ref><ref name="pmid20491800">{{cite journal| author=Zhang J, Stringer MD| title=Ophthalmic and facial veins are not valveless. | journal=Clin Experiment Ophthalmol | year= 2010 | volume= 38 | issue= 5 | pages= 502-10 | pmid=20491800 | doi=10.1111/j.1442-9071.2010.02325.x | pmc= | url=http://www.ncbi.nlm.nih.gov/entrez/eutils/elink.fcgi?dbfrom=pubmed&tool=sumsearch.org/cite&retmode=ref&cmd=prlinks&id=20491800  }} </ref>


==Pathogenesis==
==Pathogenesis==
 
Orbital cellulitis occurs secondary to [[microbial]] infiltration of the deep soft tissue cells surrounding the eye, posterior to the [[Orbital septum|orbital septum]].<ref name="pmid15318671">{{cite journal| author=Hasanee K, Sharma S| title=Ophthaproblem. Orbital cellulitis. | journal=Can Fam Physician | year= 2004 | volume= 50 | issue=  | pages= 359, 365, 367 | pmid=15318671 | doi= | pmc=2214559 | url=http://www.ncbi.nlm.nih.gov/entrez/eutils/elink.fcgi?dbfrom=pubmed&tool=sumsearch.org/cite&retmode=ref&cmd=prlinks&id=15318671  }} </ref> Damage to the cells triggers an [[Inflammation|acute inflammatory response]] resulting in [[vasodilation]], increased [[Vascular permeability|vascular permeability]], and induction of a cascade of inflammatory markers and [[White blood cells|white blood cell]] [[Chemoattractant|chemoattractants]].<ref name="acute-inflammatory-response"> U.S. National Library of Medicine Medlineplus(2014) https://medlineplus.gov/ency/article/000821.htm</ref>
Orbital cellulitis occurs secondary to microbial infiltration of the deep soft tissue cells surrounding the eye, behind the [[Orbital septum|orbital septum]].<ref name="pmid15318671">{{cite journal| author=Hasanee K, Sharma S| title=Ophthaproblem. Orbital cellulitis. | journal=Can Fam Physician | year= 2004 | volume= 50 | issue=  | pages= 359, 365, 367 | pmid=15318671 | doi= | pmc=2214559 | url=http://www.ncbi.nlm.nih.gov/entrez/eutils/elink.fcgi?dbfrom=pubmed&tool=sumsearch.org/cite&retmode=ref&cmd=prlinks&id=15318671  }} </ref> Damage to the cells triggers an [[Inflammation|acute inflammatory response]] resulting in vasodilation, increased vascular permeability, and induction of a cascade of inflammatory markers and white blood cell chemoattractants. <ref name="acute-inflammatory-response"> U.S. National Library of Medicine Medlineplus(2014) https://medlineplus.gov/ency/article/000821.htm</ref>


===Extension of adjacent infection===
===Extension of adjacent infection===
Orbital cellulitis may spread from direct extension of an acute or chronic adjacent infection. This includes the following:<br>
Orbital cellulitis may spread through direct extension of [[Acute (medicine)|acute]] or [[Chronic (medical)|chronic]] adjacent [[infections]]. This is due to the fragility of the [[Orbit (anatomy)|medial and inferior orbital walls]], the presence of natural [[foramina]] and defects in these structures, and the medial check [[ligaments]] extending from [[Extraocular muscles|extraocular structures and muscle sheaths]] to the thin medial orbital wall, which separates the [[Orbit (anatomy)|orbital cavity]] from the [[Paranasal sinus|paranasal sinuses]]. Some infections that may affect these structures include:<ref name="pmid15318671">{{cite journal| author=Hasanee K, Sharma S| title=Ophthaproblem. Orbital cellulitis. | journal=Can Fam Physician | year= 2004 | volume= 50 | issue=  | pages= 359, 365, 367 | pmid=15318671 | doi= | pmc=2214559 | url=http://www.ncbi.nlm.nih.gov/entrez/eutils/elink.fcgi?dbfrom=pubmed&tool=sumsearch.org/cite&retmode=ref&cmd=prlinks&id=15318671  }} </ref><ref name="pmid22346113">{{cite journal| author=Chaudhry IA, Al-Rashed W, Arat YO| title=The hot orbit: orbital cellulitis. | journal=Middle East Afr J Ophthalmol | year= 2012 | volume= 19 | issue= 1 | pages= 34-42 | pmid=22346113 | doi=10.4103/0974-9233.92114 | pmc=3277022 | url=http://www.ncbi.nlm.nih.gov/entrez/eutils/elink.fcgi?dbfrom=pubmed&tool=sumsearch.org/cite&retmode=ref&cmd=prlinks&id=22346113  }} </ref><ref name="pmid23107426">{{cite journal| author=Turvey TA, Golden BA| title=Orbital anatomy for the surgeon. | journal=Oral Maxillofac Surg Clin North Am | year= 2012 | volume= 24 | issue= 4 | pages= 525-36 | pmid=23107426 | doi=10.1016/j.coms.2012.08.003 | pmc=3566239 | url=http://www.ncbi.nlm.nih.gov/entrez/eutils/elink.fcgi?dbfrom=pubmed&tool=sumsearch.org/cite&retmode=ref&cmd=prlinks&id=23107426 }} </ref><br>
*Rhinosinusitis (Ethmoid sinusitis and pansinusitis)<ref name="pmid22346113">{{cite journal| author=Chaudhry IA, Al-Rashed W, Arat YO| title=The hot orbit: orbital cellulitis. | journal=Middle East Afr J Ophthalmol | year= 2012 | volume= 19 | issue= 1 | pages= 34-42 | pmid=22346113 | doi=10.4103/0974-9233.92114 | pmc=3277022 | url=http://www.ncbi.nlm.nih.gov/entrez/eutils/elink.fcgi?dbfrom=pubmed&tool=sumsearch.org/cite&retmode=ref&cmd=prlinks&id=22346113  }} </ref><ref name="pmid15318671">{{cite journal| author=Hasanee K, Sharma S| title=Ophthaproblem. Orbital cellulitis. | journal=Can Fam Physician | year= 2004 | volume= 50 | issue=  | pages= 359, 365, 367 | pmid=15318671 | doi= | pmc=2214559 | url=http://www.ncbi.nlm.nih.gov/entrez/eutils/elink.fcgi?dbfrom=pubmed&tool=sumsearch.org/cite&retmode=ref&cmd=prlinks&id=15318671  }} </ref><br>
*[[Sinusitis|Rhinosinusitis]] (ethmoid sinusitis and pansinusitis) <br>
*Dacryocystitis, Dacryoadenitis<ref name="pmid22346113">{{cite journal| author=Chaudhry IA, Al-Rashed W, Arat YO| title=The hot orbit: orbital cellulitis. | journal=Middle East Afr J Ophthalmol | year= 2012 | volume= 19 | issue= 1 | pages= 34-42 | pmid=22346113 | doi=10.4103/0974-9233.92114 | pmc=3277022 | url=http://www.ncbi.nlm.nih.gov/entrez/eutils/elink.fcgi?dbfrom=pubmed&tool=sumsearch.org/cite&retmode=ref&cmd=prlinks&id=22346113  }} </ref><br>
*[[Dacryocystitis]]/[[Dacryoadenitis]]
*Panophthalmitis<ref name="pmid15318671">{{cite journal| author=Hasanee K, Sharma S| title=Ophthaproblem. Orbital cellulitis. | journal=Can Fam Physician | year= 2004 | volume= 50 | issue= | pages= 359, 365, 367 | pmid=15318671 | doi= | pmc=2214559 | url=http://www.ncbi.nlm.nih.gov/entrez/eutils/elink.fcgi?dbfrom=pubmed&tool=sumsearch.org/cite&retmode=ref&cmd=prlinks&id=15318671  }} </ref><br>
*Panophthalmitis<br>
*Infected tumour<ref name="pmid22346113">{{cite journal| author=Chaudhry IA, Al-Rashed W, Arat YO| title=The hot orbit: orbital cellulitis. | journal=Middle East Afr J Ophthalmol | year= 2012 | volume= 19 | issue= 1 | pages= 34-42 | pmid=22346113 | doi=10.4103/0974-9233.92114 | pmc=3277022 | url=http://www.ncbi.nlm.nih.gov/entrez/eutils/elink.fcgi?dbfrom=pubmed&tool=sumsearch.org/cite&retmode=ref&cmd=prlinks&id=22346113 }} </ref><br>
*Infected [[tumor]]<br>
*Otitis media<ref name="pmid22346113">{{cite journal| author=Chaudhry IA, Al-Rashed W, Arat YO| title=The hot orbit: orbital cellulitis. | journal=Middle East Afr J Ophthalmol | year= 2012 | volume= 19 | issue= 1 | pages= 34-42 | pmid=22346113 | doi=10.4103/0974-9233.92114 | pmc=3277022 | url=http://www.ncbi.nlm.nih.gov/entrez/eutils/elink.fcgi?dbfrom=pubmed&tool=sumsearch.org/cite&retmode=ref&cmd=prlinks&id=22346113  }} </ref><br>
*[[Otitis media]]<br>
*Mucormycosis<ref name="pmid22346113">{{cite journal| author=Chaudhry IA, Al-Rashed W, Arat YO| title=The hot orbit: orbital cellulitis. | journal=Middle East Afr J Ophthalmol | year= 2012 | volume= 19 | issue= 1 | pages= 34-42 | pmid=22346113 | doi=10.4103/0974-9233.92114 | pmc=3277022 | url=http://www.ncbi.nlm.nih.gov/entrez/eutils/elink.fcgi?dbfrom=pubmed&tool=sumsearch.org/cite&retmode=ref&cmd=prlinks&id=22346113  }} </ref><br>
*[[Zygomycosis|Mucormycosis]]<br>
*Dental abscess <ref name="pmid15318671">{{cite journal| author=Hasanee K, Sharma S| title=Ophthaproblem. Orbital cellulitis. | journal=Can Fam Physician | year= 2004 | volume= 50 | issue=  | pages= 359, 365, 367 | pmid=15318671 | doi= | pmc=2214559 | url=http://www.ncbi.nlm.nih.gov/entrez/eutils/elink.fcgi?dbfrom=pubmed&tool=sumsearch.org/cite&retmode=ref&cmd=prlinks&id=15318671  }} </ref>
*[[Tooth abscess|Dental abscess]]


===Direct Inoculation===
===Direct Inoculation===
====Traumatic Inoculation====
====Traumatic Inoculation====
Orbital cellulitis may occur as a result of microbial inoculation to the orbital space due to trauma. Examples of this include:<br>
Orbital cellulitis may occur as a result of [[microbial]] inoculation to the orbital space due to trauma. Examples of this include:<ref name="pmid15318671">{{cite journal| author=Hasanee K, Sharma S| title=Ophthaproblem. Orbital cellulitis. | journal=Can Fam Physician | year= 2004 | volume= 50 | issue=  | pages= 359, 365, 367 | pmid=15318671 | doi= | pmc=2214559 | url=http://www.ncbi.nlm.nih.gov/entrez/eutils/elink.fcgi?dbfrom=pubmed&tool=sumsearch.org/cite&retmode=ref&cmd=prlinks&id=15318671  }} </ref><br>
*Fracture<ref name="pmid15318671">{{cite journal| author=Hasanee K, Sharma S| title=Ophthaproblem. Orbital cellulitis. | journal=Can Fam Physician | year= 2004 | volume= 50 | issue=  | pages= 359, 365, 367 | pmid=15318671 | doi= | pmc=2214559 | url=http://www.ncbi.nlm.nih.gov/entrez/eutils/elink.fcgi?dbfrom=pubmed&tool=sumsearch.org/cite&retmode=ref&cmd=prlinks&id=15318671  }} </ref><br>
*[[Bone fracture|Fracture]]<br>
*Penetration by a foreign body<ref name="pmid15318671">{{cite journal| author=Hasanee K, Sharma S| title=Ophthaproblem. Orbital cellulitis. | journal=Can Fam Physician | year= 2004 | volume= 50 | issue=  | pages= 359, 365, 367 | pmid=15318671 | doi= | pmc=2214559 | url=http://www.ncbi.nlm.nih.gov/entrez/eutils/elink.fcgi?dbfrom=pubmed&tool=sumsearch.org/cite&retmode=ref&cmd=prlinks&id=15318671  }} </ref>
*[[Foreign body|Penetration by a foreign body]]
====Iatrogenic Inoculation====
====Iatrogenic Inoculation====
Orbital cellulitis may also occur as a result of direct inoculation during surgical procedures such as:<br>
Orbital cellulitis may also occur as a result of direct inoculation during surgical procedures, such as:<ref name="pmid15318671">{{cite journal| author=Hasanee K, Sharma S| title=Ophthaproblem. Orbital cellulitis. | journal=Can Fam Physician | year= 2004 | volume= 50 | issue= | pages= 359, 365, 367 | pmid=15318671 | doi= | pmc=2214559 | url=http://www.ncbi.nlm.nih.gov/entrez/eutils/elink.fcgi?dbfrom=pubmed&tool=sumsearch.org/cite&retmode=ref&cmd=prlinks&id=15318671 }} </ref><ref name="pmid22346113">{{cite journal| author=Chaudhry IA, Al-Rashed W, Arat YO| title=The hot orbit: orbital cellulitis. | journal=Middle East Afr J Ophthalmol | year= 2012 | volume= 19 | issue= 1 | pages= 34-42 | pmid=22346113 | doi=10.4103/0974-9233.92114 | pmc=3277022 | url=http://www.ncbi.nlm.nih.gov/entrez/eutils/elink.fcgi?dbfrom=pubmed&tool=sumsearch.org/cite&retmode=ref&cmd=prlinks&id=22346113  }} </ref><br>
*Ocular or periocular surgeries<ref name="pmid22346113">{{cite journal| author=Chaudhry IA, Al-Rashed W, Arat YO| title=The hot orbit: orbital cellulitis. | journal=Middle East Afr J Ophthalmol | year= 2012 | volume= 19 | issue= 1 | pages= 34-42 | pmid=22346113 | doi=10.4103/0974-9233.92114 | pmc=3277022 | url=http://www.ncbi.nlm.nih.gov/entrez/eutils/elink.fcgi?dbfrom=pubmed&tool=sumsearch.org/cite&retmode=ref&cmd=prlinks&id=22346113 }} </ref><br>
*Ocular or periocular surgeries<br>
*Paranasal Sinus surgeries<ref name="pmid22346113">{{cite journal| author=Chaudhry IA, Al-Rashed W, Arat YO| title=The hot orbit: orbital cellulitis. | journal=Middle East Afr J Ophthalmol | year= 2012 | volume= 19 | issue= 1 | pages= 34-42 | pmid=22346113 | doi=10.4103/0974-9233.92114 | pmc=3277022 | url=http://www.ncbi.nlm.nih.gov/entrez/eutils/elink.fcgi?dbfrom=pubmed&tool=sumsearch.org/cite&retmode=ref&cmd=prlinks&id=22346113  }} </ref><br>
*[[Paranasal sinus|Paranasal sinus]] surgeries<br>
*Other ENT surgeries <ref name="pmid15318671">{{cite journal| author=Hasanee K, Sharma S| title=Ophthaproblem. Orbital cellulitis. | journal=Can Fam Physician | year= 2004 | volume= 50 | issue=  | pages= 359, 365, 367 | pmid=15318671 | doi= | pmc=2214559 | url=http://www.ncbi.nlm.nih.gov/entrez/eutils/elink.fcgi?dbfrom=pubmed&tool=sumsearch.org/cite&retmode=ref&cmd=prlinks&id=15318671  }} </ref>
*Other [[ENT]] surgeries


===Hematogeneous Spread===
===Hematogenous Seeding===
Infections may seed from a distant source to the retroseptal orbital soft tissue by means of hematogeneous spread in patients with bacteremia.<ref name="pmid22346113">{{cite journal| author=Chaudhry IA, Al-Rashed W, Arat YO| title=The hot orbit: orbital cellulitis. | journal=Middle East Afr J Ophthalmol | year= 2012 | volume= 19 | issue= 1 | pages= 34-42 | pmid=22346113 | doi=10.4103/0974-9233.92114 | pmc=3277022 | url=http://www.ncbi.nlm.nih.gov/entrez/eutils/elink.fcgi?dbfrom=pubmed&tool=sumsearch.org/cite&retmode=ref&cmd=prlinks&id=22346113  }} </ref><ref name="pmid15318671">{{cite journal| author=Hasanee K, Sharma S| title=Ophthaproblem. Orbital cellulitis. | journal=Can Fam Physician | year= 2004 | volume= 50 | issue= | pages= 359, 365, 367 | pmid=15318671 | doi= | pmc=2214559 | url=http://www.ncbi.nlm.nih.gov/entrez/eutils/elink.fcgi?dbfrom=pubmed&tool=sumsearch.org/cite&retmode=ref&cmd=prlinks&id=15318671 }} </ref>
In some cases, infections from a distant source may seed to the retroseptal orbital [[Soft tissue|soft tissue]] by means of hematogenous spread in patients with [[Bacteremia|bacteremia]]. This highly vascularized space, coupled with a valveless [[Inferior ophthalmic vein|inferior ophthalmic vein]], has been implicated in facilitating this mode of infection.<ref name="pmid15318671">{{cite journal| author=Hasanee K, Sharma S| title=Ophthaproblem. Orbital cellulitis. | journal=Can Fam Physician | year= 2004 | volume= 50 | issue=  | pages= 359, 365, 367 | pmid=15318671 | doi= | pmc=2214559 | url=http://www.ncbi.nlm.nih.gov/entrez/eutils/elink.fcgi?dbfrom=pubmed&tool=sumsearch.org/cite&retmode=ref&cmd=prlinks&id=15318671  }} </ref><ref name="pmid22346113">{{cite journal| author=Chaudhry IA, Al-Rashed W, Arat YO| title=The hot orbit: orbital cellulitis. | journal=Middle East Afr J Ophthalmol | year= 2012 | volume= 19 | issue= 1 | pages= 34-42 | pmid=22346113 | doi=10.4103/0974-9233.92114 | pmc=3277022 | url=http://www.ncbi.nlm.nih.gov/entrez/eutils/elink.fcgi?dbfrom=pubmed&tool=sumsearch.org/cite&retmode=ref&cmd=prlinks&id=22346113  }} </ref><ref name="pmid20491800">{{cite journal| author=Zhang J, Stringer MD| title=Ophthalmic and facial veins are not valveless. | journal=Clin Experiment Ophthalmol | year= 2010 | volume= 38 | issue= 5 | pages= 502-10 | pmid=20491800 | doi=10.1111/j.1442-9071.2010.02325.x | pmc= | url=http://www.ncbi.nlm.nih.gov/entrez/eutils/elink.fcgi?dbfrom=pubmed&tool=sumsearch.org/cite&retmode=ref&cmd=prlinks&id=20491800 }} </ref>


==Associated Conditions==
==Associated Conditions==
-Sinusitis<ref name="pmid22346113">{{cite journal| author=Chaudhry IA, Al-Rashed W, Arat YO| title=The hot orbit: orbital cellulitis. | journal=Middle East Afr J Ophthalmol | year= 2012 | volume= 19 | issue= 1 | pages= 34-42 | pmid=22346113 | doi=10.4103/0974-9233.92114 | pmc=3277022 | url=http://www.ncbi.nlm.nih.gov/entrez/eutils/elink.fcgi?dbfrom=pubmed&tool=sumsearch.org/cite&retmode=ref&cmd=prlinks&id=22346113  }} </ref><br>
The following conditions are associated with orbital cellulitis:<ref name="pmid22346113">{{cite journal| author=Chaudhry IA, Al-Rashed W, Arat YO| title=The hot orbit: orbital cellulitis. | journal=Middle East Afr J Ophthalmol | year= 2012 | volume= 19 | issue= 1 | pages= 34-42 | pmid=22346113 | doi=10.4103/0974-9233.92114 | pmc=3277022 | url=http://www.ncbi.nlm.nih.gov/entrez/eutils/elink.fcgi?dbfrom=pubmed&tool=sumsearch.org/cite&retmode=ref&cmd=prlinks&id=22346113  }} </ref>
-Upper respiratory tract infection<ref name="pmid22346113">{{cite journal| author=Chaudhry IA, Al-Rashed W, Arat YO| title=The hot orbit: orbital cellulitis. | journal=Middle East Afr J Ophthalmol | year= 2012 | volume= 19 | issue= 1 | pages= 34-42 | pmid=22346113 | doi=10.4103/0974-9233.92114 | pmc=3277022 | url=http://www.ncbi.nlm.nih.gov/entrez/eutils/elink.fcgi?dbfrom=pubmed&tool=sumsearch.org/cite&retmode=ref&cmd=prlinks&id=22346113  }} </ref><br>
*[[Chronic sinusitis]]
-Subperiosteal abscess<ref name="pmid22346113">{{cite journal| author=Chaudhry IA, Al-Rashed W, Arat YO| title=The hot orbit: orbital cellulitis. | journal=Middle East Afr J Ophthalmol | year= 2012 | volume= 19 | issue= 1 | pages= 34-42 | pmid=22346113 | doi=10.4103/0974-9233.92114 | pmc=3277022 | url=http://www.ncbi.nlm.nih.gov/entrez/eutils/elink.fcgi?dbfrom=pubmed&tool=sumsearch.org/cite&retmode=ref&cmd=prlinks&id=22346113  }} </ref><br>
*[[Upper respiratory tract infection|Upper respiratory tract infection]] 
*Subperiosteal [[abscess]]


==Gross Pathology==
==Gross Pathology==
The following are gross pathology images of orbital cellulitis:<ref name=orbitalcellulitis1>American Academy of Ophthalmology EyeWiki(2010)http://eyewiki.org/File%3AOrbital_cellulitis1.jpg</ref><ref name=orbitalcellulitis2>University of Michigan Eyes Have It(2009)http://eyewiki.org/File%3AOrbital_cellulitis1.jpg</ref>


==Microscopic Pathology==
<gallery>
 
* [[Staphylococcus aureus]], is a gram-positive bacterium which is the most common of staph infections. Staphylococcus aureus infection can spread to the orbit from the skin. Staph organisms are able to produce toxins which promote their virulence which leads to the inflammatory response seen in orbital cellulitis. Staphylococcus infections are identified by a cluster arrangement on gram stain. Staphylococcus aureus forms large yellow colonies (which is distinct from other Staph infections such as Staphylococcus epidermis which forms white colonies).
 
* [[Streptococcus pneumoniae]], is also a gram-positive bacterium responsible for orbital cellulitis due to its ability to infect the sinuses ([[sinusitis]]).  Strep organisms are able to determine their own virulence and can invade surrounding tissues causing an inflammatory response seen in orbital cellulitis (similar to Staphyloccoccus aureus). Streptococcal infections are identified on culture by their formation of pairs or chains. Streptococcus pneumoniae produce green (alpha) hemolysis, or partial reduction of red blood cell hemoglobin.
 


Image:Orbitalcellulitis1.jpg|Orbital cellulitis in the left eye of a child
Image:Orbitalcellulitis2.jpg|Bilateral orbital cellulitis gross pathology


</gallery>


==References==
==References==
{{Reflist|2}}
{{Reflist|2}}


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Latest revision as of 23:26, 29 July 2020

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Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1]; Associate Editor(s)-in-Chief: Tarek Nafee, M.D. [2]

Overview

Orbital cellulitis occurs secondary to microbial infiltration of the deep soft tissue cells surrounding the eye, posterior to the orbital septum. The infiltration can occur by means of extension of an adjacent infection (e.g., rhinosinusitis), by direct inoculation through traumatic or iatrogenic pathways, or by hematogenous spread from a distant infected site. Regardless of the mode of infiltration of the retroseptal orbital space, symptoms may arise due to the immune system triggering a regional acute inflammatory response.[1][2][3][4][5]

Pathogenesis

Orbital cellulitis occurs secondary to microbial infiltration of the deep soft tissue cells surrounding the eye, posterior to the orbital septum.[1] Damage to the cells triggers an acute inflammatory response resulting in vasodilation, increased vascular permeability, and induction of a cascade of inflammatory markers and white blood cell chemoattractants.[4]

Extension of adjacent infection

Orbital cellulitis may spread through direct extension of acute or chronic adjacent infections. This is due to the fragility of the medial and inferior orbital walls, the presence of natural foramina and defects in these structures, and the medial check ligaments extending from extraocular structures and muscle sheaths to the thin medial orbital wall, which separates the orbital cavity from the paranasal sinuses. Some infections that may affect these structures include:[1][2][3]

Direct Inoculation

Traumatic Inoculation

Orbital cellulitis may occur as a result of microbial inoculation to the orbital space due to trauma. Examples of this include:[1]

Iatrogenic Inoculation

Orbital cellulitis may also occur as a result of direct inoculation during surgical procedures, such as:[1][2]

Hematogenous Seeding

In some cases, infections from a distant source may seed to the retroseptal orbital soft tissue by means of hematogenous spread in patients with bacteremia. This highly vascularized space, coupled with a valveless inferior ophthalmic vein, has been implicated in facilitating this mode of infection.[1][2][5]

Associated Conditions

The following conditions are associated with orbital cellulitis:[2]

Gross Pathology

The following are gross pathology images of orbital cellulitis:[6][7]

  • Orbital cellulitis in the left eye of a child

    Orbital cellulitis in the left eye of a child

  • Bilateral orbital cellulitis gross pathology

    Bilateral orbital cellulitis gross pathology

References

  1. ↑ 1.0 1.1 1.2 1.3 1.4 1.5 Hasanee K, Sharma S (2004). "Ophthaproblem. Orbital cellulitis". Can Fam Physician. 50: 359, 365, 367. PMC 2214559. PMID 15318671.
  2. ↑ 2.0 2.1 2.2 2.3 2.4 Chaudhry IA, Al-Rashed W, Arat YO (2012). "The hot orbit: orbital cellulitis". Middle East Afr J Ophthalmol. 19 (1): 34–42. doi:10.4103/0974-9233.92114. PMC 3277022. PMID 22346113.
  3. ↑ 3.0 3.1 Turvey TA, Golden BA (2012). "Orbital anatomy for the surgeon". Oral Maxillofac Surg Clin North Am. 24 (4): 525–36. doi:10.1016/j.coms.2012.08.003. PMC 3566239. PMID 23107426.
  4. ↑ 4.0 4.1 U.S. National Library of Medicine Medlineplus(2014) https://medlineplus.gov/ency/article/000821.htm
  5. ↑ 5.0 5.1 Zhang J, Stringer MD (2010). "Ophthalmic and facial veins are not valveless". Clin Experiment Ophthalmol. 38 (5): 502–10. doi:10.1111/j.1442-9071.2010.02325.x. PMID 20491800.
  6. ↑ American Academy of Ophthalmology EyeWiki(2010)http://eyewiki.org/File%3AOrbital_cellulitis1.jpg
  7. ↑ University of Michigan Eyes Have It(2009)http://eyewiki.org/File%3AOrbital_cellulitis1.jpg

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