Viral infections Flashcards
List the three ways herpes viruses contribute to disease
- Direct destruction of cells and tissues
- Induction of immune responses
- Facilitating neoplastic transformation
List the 3 subtypes of herpes viruses
- Α: short reproductive cycle and irreversible destruction of cells
- Β: long reproductive cycle and slow infection process
- 𝛄: establish infection in B or T lymphocytes; associated with malignant disease
Briefly describe HSV-1 and HSV2 - 2 infections in terms of transmission
- HSV-1: transmitted via close contact with infected fluids (usually saliva)
- Gives rise to disease of the mouth and surrounding skin
- HSV-2 is transmitted by genital-to-genital contact with infected fluids or lesions
- Predominately gives rise to genital disease
- HSV-1 can cause genital disease and HSV-2 can give rise to oral illness as a consequence of acquisition via orogenital contact
- Both HSV-1 and HSV-2 lead to an initial primary infection with later episodes of less severe secondary infection in some, but not all patients
Describe primary HSV in terms of incubation, clinical features (5) and resolution
Incubation
• Arises within 1-2 weeks of acquisition of the virus
Clinical features:
• Malaise, pyrexia and lethargy
• Widespread ulceration of the oral mucosa and gingiva
• Ulcers are superficial, initially small and spherical but may coalesce to give rise to large-sized, irregular ulcers
• Can arise on any oral mucosal surface-typically all sites of the mouth affected
• Gingiva swollen, erythematous and ulcerated
Resolution:
• Resolution within 7-10 days in immunocompetent patients
• Primary HSV-2 infection of the mouth can give rise to a similar clinical pattern to that of HSV-1
Describe recurrent Herpes simplex infection in terms of:
- clinical features (4)
- triggers (5)
- resting state
Clinical features:
• Affects vermillion border of the lip
• Can arise on perioral and perinasal skin
• Prodromal -> paraesthesia -> erythema -> vesiculation -> pustule formation -> superficial ulceration -> spontaneous healing
• Clinical course of 5-7 days
Triggers: • Illness (e.g. flu) • Sunlight or UV light • Menstrual cycle • Pregnancy • Immunosuppression
Resting state:
• HSV between infections will lie dormant in the trigeminal ganglion
Describe Herpes simplex infections in terms of:
- diagnosis
- management
Diagnosis:
Primary HSV-1 infection
• Based on clinical features
• Confirmatory investigations: identification of HSV-1 DNA by PCR (polymerase chain reaction)
• In the case of adults full blood test to rule out causes of immunosuppression
Recurrent herpes labialis
• Clinically characteristic, therefore usually no investigation warranted
• Identification of HSV DNA via PCR if any confusion
Management: Primary HSV-1infection • Symptomatic relief • Topical anti-inflammatories • Topical anaesthetics • Drink fluids • Acyclovir if detected early enough
Recurrent herpes labialis
• Topical over the counter medications if needed
Describe herpetic whitlow
- Infection of the fingers when the virus is inoculated into the fingers through a break in the skin
- HSV-1 or HSV-2 may be a cause
- Occupational hazard, including within the dental profession before the widespread use of gloves
List the two forms of Varicella Zoster Virus
- HHV-3
- Primary infection: chickenpox
- Secondary Infection: shingles
- Transmission via droplets or close contact with lesions
Describe chicken pox in terms of
- Appearance
- Symptoms (3)
- oral lesions
- diagnosis and management
Appearance:
• Macular-popular cutaneous rash, vesicles, pustules and scab after 3-4 days
Symptoms:
• Fever and malaise
• Headache
• Incubation of 7-14 days
Oral lesions:
• Short lasting small white-opaque vesicles, usually on palate and buccal mucosa
• Precede cutaneous involvement
• May go unnoticed
Diagnosis:
• Confirmatory viral or serological investigations are rarely warranted
Management:
• Symptomatic relief
Describe herpes zoster (shingles) in terms of:
- distribution (2)
- how oral lesions appear
- diagnosis
- management
• Caused by reactivation of the varicella zoster virus in the ganglion of the cranial nerve
Affects dermatomes:
• Thoracic via reactivation of spinal ganglia. Painful eruptions of vesicles with ulceration and erythema
• Trigeminal nerve; ophthalmic, maxillary or mandibular divisions of one side
Oral lesions:
• vesicles, small superficial ulcers which coalesce to form larger, irregular ulcers
• Site depends on the affected branch
• Unilateral
Diagnosis
• Based on clinical manifestations
• FBC-evidence of unknown neutropenia, leukaemia, or other significant disease
Management
• Antiviral therapy is warranted
• Topical antivirals are of no benefit
• Cases of ophthalmic shingles should be referred for a specialist ophthalmology opinion
Describe the Epstein-Barr Virus in terms of the type of virus it is, transmission and manifestations (3)
- 𝛄 herpes virus
- Transmission is via the salivary route
Gives rise to a variety of different clinical illnesses
• Infectious mononucleosis
• Oral Hairy leukoplakia
• Malignancies of the head and neck
Describe infectious mononucleosis in terms of
- Onset
- clinical features (5)
- diagnosis
- management
Onset
• Arises approx. 5 weeks following viral acquisition
• Typically occurs in young adults
Clinical features • Pharyngitis • Pyrexia (fever) • Cervical • Nausea and abdominal pain • Pink maculopapular rash
Diagnosis
• Identification of atypical lymphocytosis in full blood count
• Identification of anti-EBV antibodies in serum
Management
• Symptomatic management
Describe oral hairy leukoplakia in terms of
- clinical features (3)
- diagnosis
- management
Clinical features
• Adherent, homogenous, hair-like white patches
• Lateral aspects of tongue
• Dorsal or ventral surfaces
Diagnosis
• Histopathological examination would show hyperkeratosis, acanthosis, lack of inflammatory infiltrate
• Immunohistochemistry
Management
• Does not warrant treatment
Describe cytomegalovirus in terms of transmission and manifestations
- HHV-5, β herpesvirus
- Transmission via body fluids
- Rarely gives rise to oral disease
- In immunocompromised patients, CMV can cause superficial oral mucosal ulceration with a stellate appearance
- Occurs primarily on the tongue
Describe Kaposi’s sarcoma in terms of its:
- clinical appearance
- HHV-8–neoplastic disease
- Was the most common neoplastic disease of AIDS
Clinical appearance
• Red, blue or purple macule, papule or nodule
• Typically arises at the hard-soft palate junction although can develop at other sites e.g. the maxillary gingiva
• As the disease progresses, the affected site becomes ulcerated and necrotic
• Can lead to tooth mobility and tooth loss
