Infectious Diseases Flashcards
What does the severity of infection depend on
- Pathogenicity and virulence of infecting agent
- Host resistance
- Environmental factors
Definition of infection
-Process of tissue invasion by microorganisms characterized by multiplication of these microorganisms in the body of the host to produce disease
Definition of cross infection
-Transmission of infection between patients as well as patients and health care professionals
Classification of infections
-Community acquired infections
Present at the time of admission or a visit to a hospital or incubating at that time
-Health-Care Associated Infections/ Nosocomial Infections/ Hospital-Acquired Infections:
Induced from a source outside the patient’s body (exogenous) or from within the patient’s own body (autogenous) after a visit or admission to a hospital or health care centre
Examples of microorganisms that cause disease
- Viral Infection
- Bacterial Infection
- Parasitic Infection
- Fungal Infection
Steps in diagnosing an infectious disease
-Taking a history Foreign Travel Immigrants Occupation Domestic Pets Sexual Activity Drug Addiction Tattooing Injections Transfusions
-Clinical Examination Oral Ulceration Rashes Lymphadenopathy Hetaposplenomegaly
Investigations for general infectious diseases and explanation of each
-Baseline:
Full Blood Count- looking for abnormally high/low blood cells
Blood film- thin layer of blood smeared on a microscope slide, analysing for various blood cells
C-reactive protein, blood test marker for inflammation in the body
Erythrocyte Sedimentation Rate- how long it takes for the RBC to fall, the quicker it takes, the higher levels of inflammation
-Microbiological examination of body fluids
-Immunodiagnosis
Serology: specific IgG, IgM, IgA
Antigen Detection
-Tissue Diagnosis
Aspiration/Biopsy
-Imaging Procedures
Mum brings 5yo child because they have been complaining of a sore mouth
Been generally unwell for a few days with a fever
Examination reveals multiple yellow-crested ulcers on the lips
Well-circumscribed ulcers on the hard palate
What is the likely diagnosis
Multiple well-circumscribed lesions suggest it is not malignant
Most likely to be acute herpetic gingivostomatitis (Herpes)
Based on age and presentation
First exposure to Herpes is always as a kid
Definition, Pathogen, Types, Incubation Period of Herpes Simplex
- Herpes Simplex is a viral infection caused by Herpes Simplex Virus
- Incubation period is 2-12 days
- Type 1 spread by infected saliva in the mouth and upper body
- Type 2 spread by sexual contact
Clinical Features of Herpes Simplex 1 and 2
General Features:
- Sore throat
- Fever (pyrexia)
- Lymphadenopathy
- Recurrence
Oral Features:
- Vesicles present on pharynx, buccal mucosa, gingiva, tongue, lips and face
- Often painful and last for 10 days
Skin Features:
- Can be either HSV1 or HSV2
- Herpetic Whitlow: small blisters appear on the fingers and the fleshy area around the fingertip
Eye Features:
- Usually HSV1
- Corneal involvement is serious as it may cause blindness
Genital/Anal Infections:
-Usually HSV2
Examples of conditions of Herpes Simplex Virus
- Herpetic Gingivostomatitis
- Herpes Labialis (recurrent herpes)
- Herpes Genitalis
Diagnosis of Herpes Simplex Virus Conditions
-Often clinical
Complications of Herpes Simplex Virus
- Encephalitis- affects temporal lobes
- Neonatal- serious since mortality is 60%, caused by vertical transmission of HSV2 from mother to child, which is an indication for a caesarian section
- Erythema Multiforme- hypersensitivity reaction manifesting on the skin
- Eczema herpeticum- infection causes cold sores to appear around and inside the mouth, leading to oral herpes
Definition and reactivating factors of herpes labialis
- Commonly known as cold sores
- Follows primary infection
- Usually HSV1 but can be HSV2
- Sunlight
- Trauma
- Chemical
- Hormones
- Stress
- Immunosupression
- Concurrent infections
Management of Herpes Simplex Condition
- Hydration and soft diet to prevent pain from ulcers
- Topical and systemic Acyclovir (antiviral)
- Valacylcovir
Chickenpox definition, incubation period and spread
- Initial infection of Varicella Zoster Virus
- Spread through direct contact with patients with chicken pox/ shingles
- Incubation period is 14-16 days
Clinical features and diagnosis of chickenpox
-Diagnosis clinical
- Rash that progreses from macule to papule to vesicle
- Starts on trunk of scalp
- Spreads to limbs and face
- Vesicles dry and crust
- Pruritis- very itchy
- Fever, malaise and lympodenopathy
Complications of chicken pox
- Rare
- Cellulitis (painful bacterial skin infection)
- Impetigo (common and contagious skin infection)
- Pneumonia
- Congenital abnormalities
Management of chicken pox
- Supportive
- Antihistamines
- Acyclovir for very severe cases or complications
55yo man comes to see you with right sided jaw and ear pain. He had an abscess around his upper right molar last year and had a similiar pain. He wonders if a similiar problem has recurred? You notice some a rash on his ear
- Possible Herpes Zoster
- Shingles where V2 or V3 branches of CNV are involved
- Check for other symptoms
- Differential Diagnsosis
Shingles, alternative name, and definition
- Herpes Zoster
- Characterised by the reactivation of the varicella zoter virus in a dermatomal distribution
- Can include regions of CN V
Clinical Features of Herpes Zoster
- Preceded by radicular pain and hyperaesthesia of the overlying skin
- Unilateral, dermatomal rash
- Intense erythema which rapidly becomes vesicles that crust
- Oral, palatal or pharyngeal involvement if the trigeminal nerve is affected
- Ocular involvement causes keratitis or uveitis which may result in blindness
- Ramsay-Hunt Syndrome: when shingles (reactivation of VZV) occurs in the geniculate ganglion of the VII cranial nerve
Diagnosis of shingles
Usually clinical
Complications of shingles
- Post-herpetic neuralgia
- Neurological eg. meningitis
Treatment of shingles
- Acyclovir
- Reduces the pain and accelerates healing
- Has no effect on post-herpetic neuralgia
Dental Relevance of Herpes Simplex Virus conditions
- Oral manifestations
- Vesicles present on pharynx, buccal mucosa, gingiva, tongue, lips and face
- Often painful and last for 10 days
- Herpetic whitlow
Dental Relevance of Herpes Zoster Virus
- Oral manifestations in chickenpox and shingles
- In shingles, pain if V2 or V3 of CN-V is involved
- Can often be misdiagnosed as tooth ache
- Post-herpetic neuralgia
-If a patient is having a recurrent zoster, need to question why. Immunosuppressent drugs, HIV, steroidal drugs???
A 5yo boy recently started school
- Note lesions on palate etc
- Generally unwell and feverish
Where else would you like to examine to confirm diagnosis
- Perhaps chickenpox
- Need to inspect
- Other lesions in any other places
- Any rashes
- Any swellings on the glands
Infectious mononucleosis alternative name, definition, incubation period
- Glandular fever, kissing disease
- Caused by Epstein-Barr Virus
- Incubation period is 4-14 days
- Infects B lymphocytes and causes antibody production
- Not necessarily against EBV
Clinical features of infection mononucleosis
- Sore throat
- Lymphadenopathy
- Anorexia, fever, malaise
- Intra-oral rash between hard and soft palate
- Tonsilitis with white exudate
- Palpable spleen
- Sometimes jaundice
Diagnosis of infectious mononucleosis
- Often clinical
- PCR
- Monospot test- rapid blood test to check for EBV
Complications of infectious Mononucleosis
- Hepatitis
- Respiratory obstruction
- Ruptured spleen v rare
Management of Infectious Mononucleosis
- Supportive
- Paracetemol and water
Dental relevance of infectious mononucleosis
- Cervical lymphadenopathy
- Creamy exudate over tonsils
- Rash between hard and soft palate
Mumps definition, spread, common in and incubation period
- Caused by paramyxovirus (rna)
- 16-20 days incubation period
- Spread by droplets from saliva and nasopharyngeal secretions
- Common childhood infection
Differential diagnosis of mumps
Swelling of the parotid/submandibular glands
Clinical features of mumps
- Asymptomatic in 40%
- Fever, malaise
- Enlargement of one of both parotids
- Earache and displacement of the earlobe
- Parotid papillae inflamed
- Difficulty swallowing
- Submandibular glands may be affected
Diagnosis of mumps
-Clinical
Complications of mumps
-Neurological
Aseptic meningitis
Encephalitis
- Orchitis- inflammation of the testes
- Non-parotid mumps- ovaries, thyroid, pancreas, breasts
Treatment of mumps
- Good oral hygiene as they may have some difficulties with dexterity
- Prevention by immunisation from vaccine with children 12-15 months (MMR)
- Supportive (analgesics, bed rest and fluids)
- Scrotal support
Dental Relevance of mumps
- Enlarged, tender parotid gland
- Oral hygiene may be impaired
- Difficulty as sore
Exanthema definition and examples of childhood infections that can cause it
-Skin rash accompanied by a disease or fever
- Measles
- German measles
- Enteroviral infection
- Infection mononucleosis
- Scarlet Fever
- Erythema infectiosum
- Roseola infactum
- Drug eruption
Measles definition, incubation period and spread
- Paramyxovirus
- Spread via droplet infection
- Common childhoood infection
- Incubation period is 10 days
Clinical features of measles
- Conjunctivitis
- Lymphadenopathy
- Koplik’s spots on buccal mucosa
- Florid maculopapular rash which begins behind the ears and spreads to the face and trunk- brownish discolouration remains after
Complications of measles
Gingivostomatitis
Diagnosis of measles
Often clinical but uncommon so sometimes lab tests may be done
Management of measles
- Supportive treatment (bed rest, analgesics and fluid)
- Immunisation of children ages 12-15 months
- MMR vaccine (measles, mumps and rubella)
Dental Relevance of Measles
- Koplik spots on the buccal mucosa
- Pharyngitis
- Facial rash
German Measles alternative name, definition and incubation period
- Rubella
- Caused by rubivirus
- Incubation period is 14-21 days
Clinical features of german measles
- Fever
- Malaise
- Sore throat
- Lymphadenopathy
- Rash that begins on the face and spreads to the trunk/limbs
- Pink, maculopapular, non-confluent
- Conjunctivitis
- Macular rash appears on day 3 which coalesces to form a blush
Diagnosis of german measles
- Clinical
- Essential in pregnant women
Complication of german measles
-Congenital rubella
Dental relevance of german measles
- Enlarged cervical lymph nodes
- Pharyngitis
- Facial rash
Enteroviral Infections example and definition
- Caused by Coxsackie virus A and B
- Very common in kids
- Eg. Hand-foot and mouth disease
Clinical features of enteroviral infection
- Malaise, fever and anorexia
- Sore mouth and throat
- Vesicular rash involving buccal mucosa with or without the tongue, palate or gingiva
- Hand involvement in 65% of cases
- Feet also affected
Management of enteroviral infection
No specific treatment
Definition, alternative name for Erythema infectiosum
- Fifth Disease
- Parvovirus B19
Clinical features of eryhtema infectiosum
- Constitutional symptoms uncommon
- Rash- livid erythema of cheeks
- Maculopapular on extremities and trunk
- As second fades it assumes a lacy reticular appearance
Diagnosis of erythema infectiosum
-Clinical diagnosis
Treatment of erythema infectiosum
-No specific treatment
Difference between Active and Passive immunity
- Active immunity is where the body develops its own antibodies through a disease or when you get a vaccine
- Passive immunity is when antibodies are given to you
Subsets of active immunity
1) Live attenuated vaccine
-Contains a version of living virus that has been weakened
-eg. oral poliomyelitis
measles
mumps
rubella
yellow fever
2) Inactivated organisms
-Made from microorganisms that have been killed through physical or chemical processes
-eg. whooping cough
typhoid
cholera
poliomyelitis
HepB
Rabies
3) Immiunizing components of an organism
-eg. influenza
pneumococcal
meningococcal c conjugate
4) Toxoid (inactivated toxin)
-eg. tetanus
diptheria
Examples of passive immunity
1) Natural
Mother-foetus
2) Artificial (high levels human/non-human immunoglobulin)
Human normal immunoglobulin from pooled plasma of donors eg Hep A
Specific immunoglobulin from pooled blood of convalescent patients eg. Tetanus and Hep B
Hepatitis B Virus definition, spread and incubation period
- Hepatitis B Virus DNA
- Significant to oral infection
- Present in saliva
- 45-180 day incubation period
- Parental, sexually, contact w infected blood therefore risk for healthcare workers
- Also present in saliva
Clinical features of Hep B
-Malaise, Anorexia, nausea, muscle pains
Diagnosis of Hep B
- Serological Test
- HBsAg produced during replication of virus
Management of Hep B
- All members of dental team should be vaccinated against Hep B
- Prevention by immunisation with recombinant DNA Hbs Ag vaccine
- Treatment includes bed test and avoiding hepatotoxins such as alcohol
Dental Relevance of Hep B
- Immunisation of all health care workers
- Cross-infection control
- Abnormal drug metabolism
- Abnormal clotting factors
Hepatitis C definition and clinical features
- Hep C Virus
- RNA
- Acute phase usually asymptomatic
- Lichenoid reactions and Xerostomia unlike Hep B
- No vaccination available
Dental Relevance of Hep C
- Xerostomia
- Cross Infection control
- Abnormal drug metabolism in the liver
- Abnormal clotting factors
HIV dental relevance
-Clinical signs of viral infections are early indicator of conversion to aids
Lesions strongly associated with HIV infection include:
- Candidasis both erythematous and pseudomembranous
- Hairy Leukoplakia
- Kaposi’s Sarcoma
- Non-Hodgkin’s Lymphoma
- Periodontal disease including linear gingival erythema, necrotising ulcerative gingivitis and necrotising ulcerative periodontitis
Lesions less commonly associated with HIV infection include:
- Bacterial infections
- Melanotic pigmentation
- Necrotizing stomatitis
- Salivary gland disease
- Thrombocytopoenic purpura
- Non-specific ulcerations
Scarlet Fever definition
- Group A streptococcus
- Beta haemolytic
- Produces an erythrogenic toxin that is responsible for the reddish appearance
Clinical features of scarlet fever
- Follows a pharyngeal infection
- Rash- diffuse erythema which blanches on pressure
- Skin folds are dark
- Circumoral pallor
- Strawberry tongue
Tx for scarlet fever
-Penicillin
Whooping cough definition, incubation period and clinical features
- Gram negative bacteria
- Bordetella pertusis
- 7 days incubation
- Followed by catarrhal phase which lasts 1-2 weeks
-Spasmodic phase occupies the next 4-6 weeks and consists of severe paroxysmal cough with an inspiratory whoop, vomiting, cyanosis
Complications of whooping cough
- Bronchopneumonia- secondary to inhalation of secretions during whoops
- Convulsions
- Pressure effects- subconjunctival haemorrhage
- Facial petechiae during spasm
- Cerebral haemorrhage
- Prolapse of hernias
- Laceration of lingual fraenum against the lower incisors
Investigations and tx of whooping cough
- Paranasal swabs and culture on bordet-gengou medium
- Immunofluorescent antibody test
- Treatment is basically symptomatic
Tuberculosis definition, what it affects and prevention
- Myobacterium tuberculosis
- Becomes dormant before it progresses to active TB
- Commonly affects the lungs and is communicable in this form
- May also affect any organ sysstem including lymph nodes, CNS, liver, bones, genitourinary tract and GI tract
- Prevention with immunization with BCG vaccine
- Gloves and masks should be worn
Most common oral fungal infection and who they can affect
- Oral candidasis
- Candida albicans
- Elderly pts
- Infants
- Med compromised pts
Signs include Pseudomembranous Erythematous Hyperplastic Angular Cheilitis Median rhomboid glossitis
