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Infections of the Oral Cavity Cheat Sheet by

microbiology     infections     oralcavity

Diph­the­ria

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

Phar­yng­oto­nsi­lli­tis

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

Erysipela

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

Fungal Oral Infections

 

Candida

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

Risk factors:
Extreme of ages
Diabetes Mellitus
Antibi­otics
Immuno­sup­pre­ssion
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 :
beta-h­emo­lytic
Bacitracin sensitive

Strept­ococci

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
Mechanism:
Molecular Mimicry
2. Postst­rep­toc­occal Glomer­ulo­nep­hritis
temporary and resolves without long lasting damage
Mechanism:
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
Manife­sta­tions:
pharyn­gitis, osteom­yel­itis, sepsis, invasive infections

Strept­ococcal Shock Syndrome

Cause
due to use of internal tampons
Signs:
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
 

Diphtheria

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

Diphtheria

Pseudo­mem­branous lesion of diphtheria in the oral cavity

Pharyn­got­ons­illitis

Viral vs Bacterial manife­sta­tion
*Phary­ngitis accomp­anied by rhinitis, conjun­cti­vits, diarrh­oea,etc is most likely
vir­al
*Phary­ngitis accomp­anied by fever, headache, tender cervical lymph nodes is most likely
bac­ter­ial
*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
Pathology
necrot­ising infection of pharynx
Cause
combin­ation of Fus­iform bacter­ia and Spi­roc­het­es
Manife­station
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.
Treatment
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

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Comments

SeBaez SeBaez, 15:30 8 May 18

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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