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Infections of the Oral Cavity Cheat Sheet by


Name- Coryne­bac­terium diphtheria
Lesion - Psedom­emb­ranous lesion, tightly adhered to the underlying tissue, does not produce any secretions
Toxin- may or may not produce a toxin- laboratory invest­iga­tions are hence essential. The toxin attacks cardiac myocytes and prevents protein synthesis within these cells causing infected people to die of cardiac failure
Vaccine- toxoid vaccine which produces no infection but effective due to inflam­matory response generated by host (Infection control measure)
Treatment- Antibi­oti­c(P­eni­cillin G)+Ant­itoxin
Location- upper respir­atory tract (if occurs on the vocal cords, it will obstruct the air pathway and can cause death due to asphyx­ation)
*scraping or dislodging of the lesion can damage the underlying tissue or cause bleeding
*unvac­cinated people are usually affected

Otitis Media

Caused by Pseudo­monas aeruginosa


Etiology: 80% idiopa­thic; 80% of the remaining 20% is caused by viral manife­station and the remaining 20% is caused by bacteria
Bacterial cause: usually Group A Strept­ococci (Strep­toc­occus pyogenes).

Manife­sta­tions of Group A Strep

Strept­ococcus Pyogenes (group A strep) can have 2 manife­sta­tions when they enter a host:
1. Infectious Diseases
Scarlet fever, Erysip­elas, Necrot­izing fasciitis (tissue necrosis)
2. Post Infectious Diseases / Inflam­matory diseases
Rheumatic Fever, Post infection Glomer­ulo­nep­hritis

Scarlett Fever

Strept­ococcus Pyogenes (group A strep) is a common bacterial cause for pharyn­gitis or pharyn­got­ons­ill­itis. Infest­ation of this bacteria can either cause ordinary pharyn­gitis or manifest as scarlett fever due to some strains of Strept­ococcus pyogenes being able to produce erythr­ogenic toxins .
Clinical presen­tation: rash (typicaly appearing on the head and neck first then body; more intense in skin folds called Pastia lines), perioral pallor, strawberry tongue


Diabetic patient -> skin infection -> bacterial infest­ation -> release of erthro­genic toxins -> Erysipela

Fungal Oral Infections



Structure: it is a type of a unicel­lular yeast which reproduces by budding

Risk factors:
Extreme of ages
Diabetes Mellitus
Cortic­ost­eroids (including inhalers)

Treatment: Azoles are the drug of choice because they target ergost­eroles (cell wall of fungi)

Gram positive bacteria lab algorithm

Group A strept­ococcus is :
Bacitracin sensitive


The oral cavity has billions of Group A strept­ococci and they are the most common cause of pharyn­gitis in humans

Post Infection Diseases due to Group A strep

1. Rheumatic Fever
permanent condition and eventually requires valve replac­ement
Molecular Mimicry
2. Postst­rep­toc­occal Glomer­ulo­nep­hritis
temporary and resolves without long lasting damage
Complement Activation

Rheumatic Fever (Mol­ecular Mimicry)

M protein is a sequence of amino acids present on the bacteria and also present on the cells of the heart. This bacterial M protein is the target of the host immune system. however ~20 days post infection, the host's immune cells attack their own body i.e the M cells of the heart. This is called molecular mimicry and involves cross reactive antibodies (attack foreign and later self).
Molecular mimicry often leads to post-i­nfe­ction manife­sta­tions such as Rheumatic Fever
Rheumatic fever is an example of a post-i­nfe­ctious disease (due to the response of the inflam­matory cells on self) that can develop as a compli­cation of inadeq­uately treated strep throat or scarlet fever.
Rheumatic Fever is charac­terised by transient arthiritis
It damages the heart valves and increases the rigidity of chorda tendinae causing mitral insuff­iciency

Post Strept­ococcal Glomer­ulo­nep­hritis

(Complement Activation)
this disorder produces proteins that have affinity for sites in the glomer­ulus. As soon as binding occurs to the glomer­ulus, comple­memtn is activated. Activation of complement causes generation of inflam­matory mediators. Immune complexes are trapped in a subepi­thelial pattern.

Post Infection sequelae

If blood culture involves Anti Strept­olysin O and Anti DNAase B then antibodies should be checked again and again as the child is suspecte of having a strept­ococcus infection which may lead to greater compli­cations

Arcano­bac­terium Haemol­yticum

If culture for Group A,C and G is negative for a case of repeti­tiv­e/r­ecu­rring pharyn­got­ons­illitis wherein the patient presents with fever, this bacteria must be considered because it has serious implic­ations
pharyn­gitis, osteom­yel­itis, sepsis, invasive infections

Strept­ococcal Shock Syndrome

due to use of internal tampons
Hypote­nsion, Fever >38.5, Rash, Renal Impair­ment, Coagul­opathy /DIC Alteration liver enzymes, Acute Respir­atory Distress Syndrome (ARDS), Tissue necrosis (necro­tizing fasciitis)

Fungal Oral Infections


Angular Cheillitis (Perleche)

This condition is called angular chellitis (Perleche) which is inflam­mation of the corners of the mouth usually in those elderly who wear dentures. if present, most likely candida will also be present
Candida is very common in elderly people who wear dentures and also due to the fact that they commonly have xerostomia (dry mouth) which is an excellent growth factor for the fungi


Manife­station of diphtheria on the vocal cords which can dislodge and move in the respir­atory tract causing asphyx­ation


Pseudo­mem­branous lesion of diphtheria in the oral cavity


Viral vs Bacterial manife­station
*Phary­ngitis accomp­anied by rhinitis, conjun­cti­vits, diarrh­oea,etc is most likely
*Phary­ngitis accomp­anied by fever, headache, tender cervical lymph nodes is most likely
*Throat culture and rapid screening is standard for diagnosis as they are highly sensitive for Group A strept­ococcus

Rheumatic Fever

Aschoff bodies (granu­lom­atous lesion) present in the myocardium in Rheumatic Fever

Post Strept­ococcal Glomer­ulo­nep­hritis

Acute postst­rep­toc­occal glomer­ulo­nep­hritis. The glomerulus of a patient who developed glomer­ulo­nep­hritis after a strept­ococcal infection is hyperc­ellular because of the prolif­eration of endoth­elial and mesangial cells and infilt­ration by neutro­phils.

Parovirus B19

Fifth disease (slapped cheek rash) is an acute viral disease charac­terized by mild symptoms and a blotchy rash beginning on the cheeks and spreading to the extrem­ities.
Caused by : Parvovirus B19

Fungal Oral Infections


Vincet's Angina

Clinical presen­tation
unilateral sore throat that increases in intensity over several days with earache, a bad taste and fetid breath
necrot­ising infection of pharynx
combin­ation of Fusiform bacteria and Spiroc­hetes
deep well circum­scribed unilateral ulcer of one tonsil. The base of the ulcer is gray and bleeds easily when scraped with a swab. There may be subman­dibular lympha­den­opathy.
Penicillin or Clinda­mycin and surgical debrid­ement

Vincent's Angina

deep well circum­scribed unilateral ulcer of one tonsil. The base of the ulcer is gray and bleeds easily when scraped with a swab. There may be subman­dibular lympha­den­opathy


Interesting cheat sheet. I'd suggest you to add more tags such as 'oral', or 'pathology' so students like I could find it with ease. Greetings!

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