Long Root Infection Pathway: Cavernous Sinus Involvement
Cavernous Sinus thrombosis is a very rare, but serious complication of dental infections.
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THE CAVERNOUS SINUS
The cavernous sinus is a "trabeculated cavernous spaces created by the layers of dura mater and filled with venous blood", positioned on either side of the sella turcica (Plewa, Tadi, and Gupta, 2022). It is a structure connected to many different facial components including the jugular vein, facial vein, and pterygoid plexus (3D4Medical Ltd, 2023).
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PRESENTATION OF CAVERNOUS SINUS THROMBOSIS
-periorbital swelling
- fever
- headache
- vomiting
- seizures
-1/3 mortality rate
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RISKS OF FURTHER INFECTION SPREAD
- Meningitis
- Encephalitis
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Cavernous Sinus Thrombosis Infection Pathway
Stage One: Cross-section of a healthy tooth
Cavernous Sinus thrombosis is the most dangerous of the maxillary dental pathways. The initial stages of the infection resemble that of the other maxillary dental infections, however in this case, the bacterial infection is transported into the pterygoid plexus by white blood cells and from there infects the cavernous sinus.
Stage Four: Bone resorption
It is here, within the pulp chamber, that most of the bacteria will reside, and having destroyed any access for white blood cells normally carried in the blood vessels, makes eradicating the bacteria difficult without either extracting the tooth itself or at least removing the dead contents of the pulp and root canal system and sterilising this area to kill the bacteria. The presence of bacteria means that their by-products/ toxins can leak out of the apex of the tooth, where the nerve would normally exit, and these insight an inflammatory response in the body, which causes a build-up of pressure within the apical tissues of the periodontal ligament, instigating bone resorption and so a widening the periodontal ligament.
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Stage Two: Initial Infection
During the initial stages of the tooth infection, the healthy tooth gets invaded by bacteria contained in plaque, which thrive off the carbohydrates in the mouth and produce acid, which slowly destroys the enamel layer.
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Stage Five: Transport through the Angular Vein and the Pterygoid Plexus
When white blood cells fight a dental infection in a long rooted tooth, they transport the bacteria through the angular vein and into the pterygoid plexus.
Stage Three: Invasion of the Pulp Chamber
When the bacteria gain access to the dentine, they invade the dentinal tubules and in this way gain access to the pulp chamber in the middle of the tooth. Within the pulp chamber, the bacteria incite an acute inflammatory reaction which causes an increase in the hydrostatic pressure within the tooth and leads to hypoxia and this leads to destruction of the contents of the pulp and roots canal system, effectively killing the tooth.
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Stage Six: Movement into the Cavernous Sinus
From the pterygoid plexus the bacteria can then move into the cavernous sinus (a large vascular space within the middle cranial fossa on either side of the sella tursica the eyes).
If the infection continued to spread in this way, the bacteria would have direct access to the lining of the brain, causing meningitis, or into the brain itself, causing encephalitis. In order to stop this from happening, the body tries to stop the infection from spreading and a blood clot forms in the cavernous sinus.
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The cavernous sinus thrombosis has a very high mortality of 1/3 people, with many more left with disabilities. Symptoms may include vomiting, confusion, seizures, and death.