16.1. Cavernous Sinus Thrombosis
Definition:
- It is the formation of a blood clot within the cavernous sinuses; a pair of venous cavities at the base of the brain bordered by the temporal and sphenoid bones.
o Each cavity sits either side of the Sella Turcica and are connected by the Intercavernous Sinuses
Cause:
- These clots result from the spreading of infections from the nose, sinuses, ears and/or teeth. - The infections can spread very easily since the flow of venous blood in the brain isn’t
unidirectional due to the lack of valves.
- Furthermore, the venous system of the brain is highly anastamotic forming a complex network of vessels.
o In this case, the Cavernous Sinuses communicate with: Superior Ophthalmic Vein
Pterygoid Plexus
Each other via Intercavernous Sinuses
- Spread of infection results in the veins initiating the inflammatory response which results in
blood stasis.
o The clot forms and the build of up fluid pressure can then alter the direction of veinous
blood flow until the clot ends up in the Cavernous Sinus
Relevance to Dentistry
- Whilst dental infections only account for around 10% of occurrences, it is still necessary to keep it in mind.
- Dental-related occurrences are due to spread of streptococcus and staphylococcus aureus from tooth infections with the most common origin being the canines, both maxillary and mandibular - The upper and lower teeth are drained by the Superior and Inferior Alveolar Veins.
o These two veins then drain into the facial vein which then anastamoses with the
Superior Ophthalmic vein.
Symptoms
- General symptoms include:
o Loss of, or blurred vision o High Fever
o Sensitivity to light o Swelling of the optic region
o Headaches o Paralysis of certain cranial nerves
which pass through the cavernous sinus. (III, IV, V and VI)
- Remember that certain cranial nerves run along the lateral wall of the cavernous sinus and can be compressed by the clot or swelling.
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Treatment
- Patients are treated with high-dose antibiotics given intravenously. - Corticosteroids can also be used to reduce the swelling.
- No response to medication will result in surgery to drain the fluid.
16.2. Designing a Periodontal Flap
16.3. Bell’s Palsy
Definition:
- It is a TEMPORARY facial paralysis resulting from damage or trauma to the Facial Nerves (VII). - If the lesion is peripheral, it will only affect one side of the face.
- Central lesions will result in partial paralysis on both sides but to different degrees depending on
which motor nucleus is affected.
- When talking about Bell’s Palsy, we are only looking at paralysis of the MOTOR FUNCTIONS of the Facial Nerve, not the sensory.
Causes:
- It occurs when the Facial Nerve is swollen, inflamed or compressed.
- For the moment, Bell’s Palsy is idiopathic in that no one knows for certain what causes it. - Most scientists believe that a viral infections such as meningitis or herpes simplex causes the
nerve to swell and become inflamed, generating pressure within the Facial Canal and restricting the blood and oxygen supply to the nerve cells.
- In some milder cases, there is damage only to the myelin sheathes of the nerve.
Symptoms
- Paralysis of the muscles of facial expression. The severity of the paralysis may vary. - Drooping of the eyelid and corner of the mouth, drooling, dryness of the eye or mouth,
restriction of taste and excessive lacrimation in one eye.
Treatment/Management
- Remember that the severity of Bell’s Palsy will vary between individuals.
- Most cases are mild and will not require treatment and usually subside eventually on their own. - Acyclovir is used to treat herpes and can be used to stop progression.
- Steroids such as Prednison can be used to reduce the inflammation and swelling. - Analgesics like aspirin may help relieve any pain
Page | 114 - Eye protection is also important as Bell’s Palsy can inhibit the eye’s ability to close and will
therefore be exposed to irritation and drying out. Eye patches are used and lubricating eye drops also help.
- For some, physical therapy to stimulate the facial nerve may help.
For Dentists
- The point of this is that when performing an Inferior Dental block, if we inject into the parotid gland we anaesthetise the Facial Nerve resulting in Bell’s Palsy-LIKE symptoms but not Bell’s
Palsy.
- We can also help diagnose it.
16.4. Ludwig’s Angina
Definition
-
Ludwig’s Angina is a severe, potentially life-threatening cellulitis or connective tissue infection of the floor of the mouth/Submandibular space.o
It is seen as an extra-oral swelling of the lower jaw and upper neck.-
It occurs bilaterallyo
Because the retropharyngeal space in which it occurs spans the whole floor of the mouth allowing for this spread.Causes
- Dental infections account for approx. 80% of cases of Ludwig’s Angina.
- Most of the time, it is an infection of the roots of the Lower Molars such as a tooth abcess. - Infections of the gums around partially erupted molars (usually lower 8) can also cause it.
Signs and Symptoms
- Bilateral swelling of the lower jaw and upper neck.
- Difficulty breathing and swallowing due to constriction of the neck. - If serious, it can spread to the mediastinum and cause pericarditis - Fever
- Faster, weaker heart rate.
- Constriction of voice box will change the voice.
Treatment/Management
- Penicillin is usually used to fight the infection given intravenously.
- A referral to a max-fax surgeon may be necessary to incise and drain the fluid
- If airways are constricted enough, a tracheostomy may be necessary to allow airflow. - Dental treatment to remove infection.
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16.5. Principles for Injecting Local Anaesthesia
1. Palpate the location to inject before you pick up the needle as once the needle is in your working hand, you other hand cannot be in the patient’s mouth.
a. Use the mirror to retract instead.
2. When inserting the needle, insert until you hit bone and retract a little before injecting a. Don’t inject into the bone as the Periosteum is very sensitive
3. Before injecting, pull the plunger a little to suck up some fluid to make sure you aren’t injecting into a vessel.