1) Infectious Diseases Flashcards
What is infection?
Infection is a process of tissue invasion by microorganisms, characterized by multiplication of these microorganisms in the body of the host to produce disease.
• Cross infection implies transmission of infection between patients as well as patients and health care professionals.
Community acquired infections ?
that may be present at the time of admission or a visit to a hospital or incubating at that time.
Health-Care-Associated Infections previously known as Nosocomial Infections or Hospital-Acquired Infections ?
that could be 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.
What are examples of infectious disease?
Viral infection
Bacterial infection
Fungal infection
Parasitic infection
Diagnosis
• History : foreign travel, immigrants, occupation, domestic pets, sexual activity, drug addiction, tattooing, injections and transfusions.
• Examination : oral ulceration, rashes, lymphadenopathy, hepatosplenomegaly
Investigations
- Baseline : FBC and film, CRP, ESR, liver function tests, urinalysis and chest x-ray
- Microbiological examination of body fluids
- Immunodiagnosis : serology : specific IgG, IgM, IgA antigen detection : e.g. ELISA
- Tissue diagnosis : aspiration / biopsy
- Imaging procedures
See slides 9-10
What are the two types of herpes simplex and how is each spread?
• Herpes simplex type 1 spread by infected saliva
• Herpes simplex type 2 spread by sexual contact
What is the incubation period and clinical features of herpes simplex?
• Incubation period is 2-12 days
• Clinical features :
• Orolabialis infection
• sore throat, fever
• vesicles on pharynx, buccal mucosa, gingiva & tongue which spreads to lips and face
• lymphadenopathy
• recurrence
What are the different types of infections of herpes simplex and which virus/viral infection causes them?
- Skin infections
• hsv-1 or hsv-2
• herpetic whitlow
• primary infections - Eye infections
• usually hsv-1
• corneal involvement is serious since it may cause blindness - Genital / anal infections
• usually hsv-2
What are the complications and treatment of herpes simplex?
Complications :
• encephalitis - affects temporal lobes
• neonatal - serious since mortality is 60 %
• due to transfer of HSV-2 during parturition
• indication for a caesarian section
• erythema multiforme
• eczema herpeticum
Treatment :
• Acyclovir, Valacylcovir
Important to recognise due to risk of cross-contamination to other patients
See slide 14
What is herpes zoster and what are the clinical features?
- Reactivation of varicella zoster virus
- Clinical features :
• preceded by radicular pain and hyperaesthesia of overlying skin
• rash - unilateral, dermatomal
• intense erythema which rapidly become vesicles which crust
• oral, palatal or pharyngeal involvement if Trigeminal nerve affected
• ocular involvement causes keratitis or uveitis which may result in blindness
• Ramsay-Hunt Syndrome – reactivation of VZV in the geniculate ganglion of the VII cranial nerve
(HERPES ZOSTER IS SHINGLES)
Complications and treatment of herpes zoster?
Complications :
• post-herpetic neuralgia
• neurological e.g. Meningitis
Treatment :
• acyclovir
• reduces pain / accelerates healing
no effect on post-herpetic neuralgia
What is Infectious mononucleosis caused by, incubation period and clinical features?
- Epstein-Barr virus
- Incubation period is 4-14 days
- Clinical features :
anorexia, malaise, fever
sore throat
cervical lymphadenopathy
macular rash n.b. Ampicillin
tonsillitis with white exudate
palatal petechiae
palpable spleen
jaundice (10%)
Don’t need to know but it is basically MONO what the college students get
What are the complications, diagnosis and treatment of Infectious mononucleosis?
- Complications :
• hepatitis
• respiratory obstruction
• ruptured spleen (rare - told to avoid contact sports) - Diagnosis :
• Monospot test
• blood film
•Paul-Bunnel test - Treatment is supportive
What is Chicken pox caused by, clinical features and incubation period?
- Varicella zoster virus
- Incubation period is 14-16 days
- Clinical features :
• rash - appears in crops and progresses from macule to papule to vesicle
• starts on trunk or scalp
• spreads to limbs and face
• vesicles dry and crust
• pruritis
• shallow ulcers on mm’s
What are the complications and treatment of chicken pox?
Complications are rare and include:
• cellulitis or impetigo
• pneumonia
• neurological e.g. Acute cerebellar ataxia, Reye’s syndrome
• congenital abnormalities
Treatment :
• Antihistamines
• Acyclovir (severe cases/complications)
What is mumps caused by, how is it spread, incubation period and clinical features?
- Paramyxovirus (rna)
- Incubation period is 16-21 days
- Spread by droplets from saliva and nasopharyngeal secretions
- Clinical features :
asymptomatic in 40%
fever, malaise, “angle pain”
enlargement of one or both parotids
earache and displacement of earlobe
parotid papillae inflamed
difficulty in swallowing
submandibular glands may be affected
What are the complications and treatment of mumps?
Complications :
• neurological - aseptic meningitis, encephalitis
• orchitis - 20-25% in post pubertal
• non-parotid mumps - ovaries, thyroid, pancreas, breasts
Treatment :
• good oral hygiene
• scrotal support
• bed rest in meningitis
Childhood exanthems? ( exanthem - widespread rash )
• Measles
• German measles
• Enteroviral infection
• Infectious mononucleosis
• Scarlet fever
• Erythema infectiosum
• Roseola infantum
• Drug erruption
ie viral rashes
What are measles caused by, incubation period, clinical features, complications and treatment?
- Paramyxovirus (RNA)
- Incubation period is 10 days
- Clinical features :
• conjunctivitis (res eyes),
• 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 :
• gingivostomatitis - Treatment is supportive while any complications are treated as appropriate
German measles caused by etc?
- Rubella (RNA)
- Incubation period: 14-21 days
- Clinical features :
• fever, malaise, catarrhal
• lymphadenopathy
• rash - starts face → trunk/limbs
• pink maculopapular, non-confluent
• Conjunctivitis - Diagnosis: essential in pregnant women
- Complications: congenital rubella
Enteroviral infections caused by etc?
- Coxsackie virus a and b
- E.g. Hand-foot-and-mouth disease
- Clinical features :
• malaise, fever, anorexia
• sore mouth and throat
• vesicular rash involving buccal mucosa with or without the tongue, palate or gingiva
• hands are involved in 65%of cases
• feet often affected - No specific treatment
Erythema infectiosum caused by etc?
- Parvovirus B19
- Clinical features :
• constitutional symptoms uncommon
• rash - livid erythema of cheeks (slapped cheeks)
• then maculo-papular on extremities and trunk
• as second fades it assumes a lacy reticular appearance - Diagnosis is made clinically and there is no specific treatment
Active immunity
- Live attenuated vaccines : oral poliomyelitis, measles, mumps, rubella, yellow fever, bcg
- Inactivated organisms :
whooping cough, typhoid, cholera, poliomyelitis, hepatitis b, rabies - Immunising components of organism :
influenza, pneumococcal, meningococcal c conjugate (surface polysaccharide with protein) - Toxoid (inactivated toxin)
tetanus, diphtheria
Passive immunity
- Natural transmission from mother to foetus
- Artificial (high levels human / non-human immunoglobulin)
Two types:
a. Human normal immunoglobulin from pooled plasma of donors e.g. Hepatitis a
b. Specific immunoglobulin from pooled blood of convalescent patients e.g. Tetanus, hepatitis b, rabies, varicella / zoster
Hepatitis B and C?
Hepatitis viruses B and C (HBV and HCV)
Significant to oral infection
Transmitted via contact with infected blood, and thus pose a risk to health-care workers.
HBV is also present in saliva.
There is substantial reduction of risk by immunization with a recombinant hepatitis B vaccine.
Hepatitis B
DNA virus.
Incubation period: 45 to 180 days.
HbsAg main.
Mode of transmission: direct contact with infected blood.
Prevention: all members of dental team should be vaccinated against hepatitis B
Hepatitis C
Hepatitis C virus
It is a RNA virus.
The acute phase of HCV infection is usually asymptomatic and only approximately 10% individuals have overt hepatitis.
Clinical features: Lichenoid reaction; Xerostomia
HIV
Human Immunodeficiency Virus (HIV)
HIV seropositive periodontal conditions, candidiasis
Clinical signs of viral infections as early indicators of conversion to AIDS
Increased frequency of minor oral infections.
See slide 40
Diseases strongly associated with HIV infection
Candidiasis
Erythematous
Pseudomembranous
Hairy Leukoplakia
Kaposi’s Sarcoma
Non-Hodgkin’sLymphoma
Periodontal disease
•Linear gingival erythema
•Necrotising (ulcerative) gingivitis
•Necrotising (ulcerative) periodontitis
See 42-44
Bacterial- Scarlet Fever what bacteria causes and what are the clinical features and treatment?
- Group a beta-haemolytic streptococci which produces erythrogenic toxin
- Clinical features :
• follows a pharyngeal infection
• rash - diffuse erythema which blanches on pressure
• skin folds are dark
• circumoral pallor
• strawberry tongue - Treatment is penicillin
Bacterial infection - Whooping cough?
1.Bordetella pertussis (gram negative bacillus)
2.Incubation period is 7 days and is followed by the “catarrhal” phase which lasts 1-2 weeks
3.Spasmodic phase occupies next 4-6 weeks & consists of :
• severe paroxysmal cough with an inspiratory “whoop“
• vomiting
• cyanosis or apnea
- Complications :
• 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 - Investigation :
• paranasal swabs and culture on bordet-gengou medium
• immunofluorescent antibody test - Treatment is basically symptomatic
Tuberculosis
Pulmonary tuberculosis is an infectious disease caused by Mycobacterium tuberculosis .
In many cases, M tuberculosis becomes dormant before it progresses to active TB.
It most commonly involves the lungs and is communicable in this form, but may affect almost any organ system including the lymph nodes, CNS, liver, bones, genitourinary tract, and gastrointestinal tract.
Prevention: Immunization with BCG vaccine.
Gloves and mask should be worn.
Fungal infections
Oral candidiasis
Common opportunistic infection from yeast-like organism Candida albicans.
Typically elderly patients
Infants
Medically compromised individuals
Signs
Pseudomembranous
Erythematous
Hyperplastic
Angular cheilitis
Median rhomboid glossitis
