Space infection is one of the most dreaded conditions to be treated by a general dentist.
My firm belief is that an oral and maxillofacial surgeon has to be consulted for every space infection case.
I also feel that a general dentist should have the basic knowledge of the pathophysiology and management of the head and neck space infection.
Now please note that I will not be going into the details of each and every space infection.
Instead, I will be giving you a general overview of Head & Neck space infection.
The term Space Infection is misleading.
In reality there is no space between the different fascial layers of head and neck.
They are actually “Potential” spaces.
What this means is that there is no space between the fascia but in future a space may get created by the Hydraulic pressure from the pus formed because of the infection.
This can be easily understood by an example of a balloon.
When the balloon is in a deflated state then there is no space between the balloon walls as they stick to each other.
But when we start pushing water inside the balloon, the balloon walls are pushed apart from each other by Hydraulic pressure from water to create a space to accommodate the incoming water.
Same is with pus. Pus, like water, is a liquid.
So, when there is continuous production of pus from the site of infection (like periapical abscess) it spreads into the surrounding tissue compartments by Hydraulic pressure and creating a space in these fascial compartments in the process to accommodate the propagating pus.
This same principle of Hydraulic pressure is applied in indirect sinus lift procedure for sinus augmentation for dental implant procedure.
Now coming back to the topic of space infection.
These so-called thin tissue compartments are filled with loose connective tissue which can easily be eroded and that further facilitates the spread of the pus in space infection.
Remember there are different etiological factors that may lead to a space infection like dental caries followed by periapical abscess, trauma, periodontal abscess, implant surgery, reconstructive surgery, contaminated needle puncture and oral malignancies.
Most common of these is dental caries and periapical abscess and i will be talking in detail about it in this article.
The progression of the infection occurs in a fairly predictable chronology.
First there will be deep dental caries that leads to invasion of the dental pulp by the bacteria.
This if left untreated leads to pulp tissue necrosis.
This necrotic pulp acts as a favourable environment for proliferation of bacteria (usually anaerobic).
This infection then propagates to the periapical region and leads to pus formation in periapical region. This is called as periapical abscess.
This periapical abscess propagates like a water filled balloon.
It applies pressure on the bone in all directions leading to equal bone resorption in all directions.
Which ever side the bone is thinner, the pus would exit the bone from that side.
And depending on the attachments of different muscles a primary space is involved.
So, to accurately diagnose a space infection, good knowledge of anatomy is required.
I will explain this with examples of different teeth one by one.
But before that, let us first talk about some anatomy (some muscles specifically).
Buccinator muscle
Buccinator muscle has its origin in the alveolar bone of maxilla and mandible, at the level of the tooth root apices.
This origin continues backwards into the Pterygomandibular Raphe.
It inserts into the angle of the mouth into the Orbicularis Oris muscle.
Lateral to the muscle, there is subcutaneous tissue and skin.
This area between skin and buccinator muscle is a potential space as these two layers can be easily pushed apart by the pus.
This potential space is called Buccal space.
Mylohyoid muscle
This muscle originates from the mylohyoid line (mylohyoid ridge) present at the medial surface of the body of the mandible and inserts at the superior border of the body of hyoid bone.
This muscle divides the floor of the mouth in two potential spaces.
Superiorly, sublingual space is present between the mylohyoid muscle and the mucosa of the floor of the mouth.
Inferiorly, submandibular space is present between mylohyoid muscle and superficial layer of the deep cervical fascia.
The platysma muscle is present immediately inferior to the superficial layer of deep cervical fascia and the two are in direct contact.
The point to remember here is that the mylohyoid line of the mandible is present at the level of the root apices of the mandibular posterior teeth.
Mentalis Muscle
This muscle originates from the alveolar bone buccal to the mandibular lateral incisors and inserts into the skin of the chin.
Here also, the origin of the muscle is at the level of the root apices of mandibular anterior teeth.
Levator labii superioris
This muscle originates from the infraorbital margin and inserts into the skin and orbicularis oris muscle of the lips.
This muscle forms a triangular space with bone posteriorly and vestibular mucosa inferiorly.
This space is Canine Space.
Let us now talk about scenarios where the periapical abscess of different teeth take form of different space infections and what governs them.
Maxillary posterior teeth
If in maxillary molars and rarely premolars, there is periapical abscess.
If left untreated it will keep on expanding and eroding the surrounding bone in all directions (just like water expands balloon in all directions).
Depending on the location of periapical abscess (buccal roots or palatal roots) the puss will exit either through the palatal cortex into the palate (palatal abscess) or through the buccal cortex into the buccal space (buccal space infection) or vestibule (vestibular space infection).
If the periapical abscess is present on the buccal roots, whether the infection will be the buccal space infection or the vestibular space infection depends on the level of the molar roots.
Now, we all know that buccinator muscle has origin at the alveolar bone of maxilla and mandible, at the level of the tooth root apices.
If the origin of the buccinator muscle is slightly above the level of the root apices then the pus will drain out into the vestibule. This is Vestibular space infection.
If the origin of the buccinator muscle is slightly below the level of the root apices then the pus will drain out into the buccal space leading to Buccal space infection.
So, it is clear that the muscles governs the spread of the infection.
Also note that in case of maxillary third molars, instead of going palatal or buccal, the pus may travel posteriorly into the infratemporal space.
This leads to Infratemporal Space infection.
Maxillary Anterior Teeth
If the periapical abscess in the canine or sometimes lateral incisors is left untreated, it will keep expanding thereby eroding the adjacent bone.
And it will keep expanding until the abscess cavity reaches either the palatal or labial cortex of the anterior maxilla.
If the palatal cortex is perforated then it will lead to pus collection between palatal mucoperiosteum and the bone. This is palatal abscess.
If the labial cortex is perforated then it will lead to pus collection in a triangular space between the bone, vestibular mucosa and Levator labii superioris.
This is Canine space infection.
When talking about infection in anterior maxilla, the discussion will be incomplete without the mention of the Danger Zone of face, also called as Danger triangle of face.
Due to the valveless nature of the veins in the head and neck region, it is possible, although rare, for retrograde infection from the nasal area to spread to the brain, causing cavernous sinus thrombosis, meningitis or brain abscess. This can be fatal for the patient.
Mandibular posteriors Teeth
In mandibular molars and rarely premolars periapical abscess, the pus will either exit the bone by eroding the buccal cortex or lingual cortex depending on the amount of bone available.
If the pus exits the bone buccally, then it will either cause Vestibular space infection or Buccal space infection.
Again, we know that buccinator muscle has origin at the alveolar bone of maxilla and mandible, at the level of the tooth root apices.
If the origin of the buccinator muscle is slightly below the level of the root apices of mandibular posterior teeth, then the pus will drain out into the vestibule leading to Vestibular space infection.
If the origin of the buccinator muscle is slightly above the level of the root apices of mandibular posterior teeth, then the pus will drain out into the buccal space leading to Buccal space infection.
If the pus exits the bone lingually, then it will either cause Sublingual space infection or Submandibular space infection depending on the level of mylohyoid muscle attachment.
If the origin of the mylohyoid muscle is slightly below the level of the root apices of mandibular posterior teeth, then the pus will drain out into the sublingual space leading to Sublingual space infection.
If the origin of the mylohyoid muscle is slightly above the level of the root apices of mandibular posterior teeth, then the pus will drain out into the submandibular space leading to Submandibular space infection.
Mandibular Anterior Teeth
In case of mandibular anterior teeth, if the pus exits the bone lingually then it will lead to sublingual space infection.
In case the pus exits the bone labially then it may lead to vestibular space infection or Submental space infection, depending on the level of origin of mentalis muscles.
Similar to the previous examples, the level of origin of mentalis muscles, if above the level of root apices of lateral incisor, will push the pus into the space between the platysma and the mylohyoid muscle. This is submental space infection.
All the spaces mentioned above are called as primary spaces as they are the first ones to get involved after the infection moves out of the bone into the soft tissue.
The spaces that are involved after the primary spaces are called as secondary spaces.
Examples of secondary spaces are Submassetric space, Pterygomandibular space, Deep temporal space, Lateral pharyngeal space and Retropharyngeal space.
It is not unusual to see the above mentioned primary and secondary spaces to present clinically in combination.
An example of this is Ludwig's Angina where bilateral submandibular, bilateral sublingual and submental spaces are involved.
Also, the pace at which the infection spreads also depends on the host. If the host immunity is already compromised or in a host with uncontrolled diabetes, the spread of infection will be at a rapid rate.
Now let us talk about the signs and symptoms that you will see in a space infection case.
Remember, every infection leads to inflammation.
Same is the case with space infection.
So, you will see all the signs of inflammation.
These signs are –
Rubor (Redness)
Tumor (Swelling)
Calor (Heat or raised localised temperature)
Dolor (Pain)
Apart from the above mentioned signs the patient will also have Fever (a classical sign of infection).
Raised localised temperature (calor) or generalised temperature (fever) is a defensive mechanism of our body. When our body is invaded by micro-organisms, our body raises its temperature in an attempt to kill off these micro-organisms.
Other signs that may be seen in a space infection are –
Headache
Trismus (reduced mouth opening) – in case of submassetric, pterygomandibular and deep temporal spaces.
Lymphadenopathy
Draining sinus (Intraoral or Extraoral)
Odynophagia (difficulty in swallowing)
Dysphonia (difficulty in talking)
Increased salivation
Dyspnea (difficulty in breathing)
Bad breath
Torticollis (asymmetrical head or neck position)
Inability to move head
If a patient has dyspnea, torticollis or inability to move head consider as a life threatening condition as this indicates retropharyngeal space involvement which left untreated may progress to Mediastinitis and then death.
Cellulitis vs Abscess
A space infection can present itself as either a cellulitis or an abscess.
Cellulitis is an acute and rapidly progressing infection of the loose connective tissue that is present between the different layers of fascia. In a cellulitis, there is little pus formation.
An abscess is a cavity containing pus which is chronic in nature.
The most common microorganism to be found in cellulitis is a streptococcus.
Streptococci produce enzymes such as streptokinase (fibrinolysin), hyaluronidase, and streptodornase.
These enzymes breakdown fibrin and connective tissue ground substance and lyse cellular debris, thus facilitate rapid spread of bacterial along the potential fascial spaces.
The most common microorganism to be found in a head and neck abscess is a staphylococci along with bacteroides. These are responsible for collection of large amounts of pus within the fascial space.
So how do we differentiate between cellulitis and abscess clinically?
A cellulitis is a large generalized swelling with diffuse borders whereas an abscess is a localized swelling with well-defined borders.
You can use Contrast Enhanced CT scan to differentiate between cellulitis and abscess.
Radiological Examination
If you want to find out the etiological factor (usually dental caries) an OrthoPantomoGram is preferably as it gives you a complete radiographic picture of the patient’s upper and lower jaws.
Also, there may be trismus and other intraoral radiographs may not be possible. In those cases also OPG is the radiograph of choice.
If you wish to view the site of infection on a radiograph, the imaging modality of choice is the Contrast Enhanced Computed Tomography (CECT).
CECT also helps in differentiating a cellulitis from an abscess. An abscess and a cellulitis look similar on the CECT except for the facts that an abscess is well defined and has an enhanced peripheral rim.
Management
As I mentioned in the beginning of the article, I would suggest a general dentist to always consult an Oral & Maxillofacial Surgeon for head and neck space infections.
But that should never stop anyone from learning about the management of these infections.
Management is aimed towards -
Airway maintenance
Early antibiotics
Early surgical intervention (Incision & Drainage)
Address the Etiology
Proper fluid intake
Airway Maintenance
If airway appears to be compromised then Endotracheal intubation should be considered.
But sometimes, due to para pharyngeal or retropharyngeal space infection the throat mucosa is very fragile and may rupture while Endotracheal tube insertion.
This will lead to drainage of pus from these spaces to be aspirated into the lungs leading to possibly death of the patient.
In such cases, if throat mucosa appears to be inflamed and fragile, tracheostomy should be considered as a preferable option.
Early Antibiotics
Empirical antibiotic therapy should be started as soon as possible.
But for that you need to have a sound knowledge of the most common microorganism to occur in such infections.
Also, empirical antibiotic therapy consists of antibiotics that have the widest coverage thereby targeting all the microorganisms that may possibly cause head and neck infection.
At present, Amoxycillin + Clavulanic acid + Metronidazole combination is the empirical therapy of choice.
But recent studies and my own experience suggest that there is increasing resistance to this combination owing to the antibiotic abuse.
Another combination that can be used is Ceftriaxone+ Metronidazole.
I prefer Intravenous antibiotics in majority of my space infection cases BUT the decision whether the antibiotics are to be administered orally or IV should be based on the clinical picture of the patient.
For example, if there is dysphagia or odynophagia, of course the patient will find it difficult to swallow antibiotics orally and hence IV antibiotics are the way to go in such cases.
Another thing to remember is, whenever possible, send the collected pus for culture and antibiotic sensitivity test. This helps the doctor in selecting the most effective antibiotic with the narrowest spectrum possible.
As soon as the test results from the antibiotic sensitivity tests are available, empirical antibiotics should be replaced with the appropriate antibiotics.
This eliminates the chances of antibiotic resistance.
Early surgical Intervention
By early surgical intervention I mean early Incision & Drainage of pus.
Many would say that there is no need of Incision & Drainage in Cellulitis.
I would say, they couldn't be more wrong. Of course cellulitis in its initial stage can be managed solely by antibiotics but cellulitis in its advanced stage has to be managed with Incision & Drainage in conjunction with antibiotics.
Cellulitis is most commonly caused by streptococci. These microorganisms from the streptococci family produce gases which lead to increased pressure within these fascial spaces.
This increased pressure causes occlusion of peripheral blood vessels leading to reduction of the blood supply of that area.
This leads to necrosis of the tissue which further facilitates the spread of the infection.
Also, as there is hampered blood supply, the antibiotics are not able to achieve the required local concentration in the infected area to kill the microorganisms.
Incision & Drainage relieves the pressure in cellulitis, hence re-establishing normal blood supply.
Incision & Drainage relieves the pressure in an abscess by removing the pus from the abscess cavity.
Hence, be it a cellulitis or an abscess, it has to be managed by Incision & Drainage.
Now, this Incision & Drainage can be performed Intraorally or Extraorally.
I personally prefer to perform Incision & Drainage extraorally as it is easier to perform and the pus is exits along the gravity as the incision is usually placed at a level inferior to the location of the abscess.
This incision is further kept open by the help of a corrugated rubber drain, a tube drain or a glove drain.
This facilitates removal of any new pus that is formed in the next few days.
The placed drain is then covered by a loose Cotton Gamjee Pads to collect the pus that is drained.
These pads have to be changed every 12 hours.
Using Cotton Gamjee Pads prevents soiling of the patient’s clothes and it also aids in keeping a record of the amount of pus drained throughout the day.
The drain that is placed has to be removed after 2 days.
Many surgeons advocate the use of steroids to relieve inflammation. This is debatable.
I, personally, don’t prefer to use steroids in such patients as steroids suppress the immunity of the patient which may further facilitate the spread of the infection.
Address the Etiology
This is a no brainer.
As long as you don’t address the etiological factor, there is no point in performing Incision & Drainage as the infection may recur again.
This etiological factor can be a carious tooth, periodontal abscess, dental implant or a malignancy.
In case of a carious tooth, if you feel that the tooth can be saved by Root Canal Treatment then perform RCO followed by pulp extirpation from the root canals.
In cases where the tooth cannot be saved then it has to be extracted while performing Incision & Drainage.
In case of periodontal abscess, proper drainage and debridement of the abscess followed by Incision & Drainage should be sufficient.
In case of a Dental implant, the infected implant has to be removed and proper curettage of the socket to be done followed by Incision & Drainage.
Fluid Intake
Fluid intake of the patient is reduced due to the patient’s inability to swallow properly.
Also, because of the fever, fluid requirements of the body increases.
These two things combined may lead to dehydration.
Hence, fluid requirements of the patient have to be met by intravenous fluids like Normal saline and ringer lactate.
If the patient is able to drink properly, then IV fluids are not required and the patient should be administered 3.5-4 litres of fluids orally daily.
Also, from the next day of Incision & Drainage the patient should be instructed to hot fomentation (heat application) over the site of infection using a warm moist pack or warm saline rinses.
This softens the hard swelling of a cellulitis and also causes vasodilation of the peripheral blood vessels leading to faster resolution of the infection.
Even when the patient is discharged from the hospital, regular post-operative followup has to be done to ensure proper resolution of the infection.
So that’s a general overview of Head & Neck Space infection.
I hope this article helped you guys, especially to the ones who requested this topic specifically.
Let me know in the comment section, whether you have experienced any such complication and how you managed it.
Also, do let me know what topics would you want me to write about next. The topics can be from local anesthesia, Oral & Maxillofacial Surgery or Medical emergencies.