Shingles Flashcards
What is shingles?
A viral disease caused by the human herpes virus 3 (HHV-3)
What is HHV-3 more commonly known as?
Varicella zoster virus (VZV)
When does shingles occur after infection with VZV?
After reactivation of primary infection that usually occurs during childhood
What does primary infection with VZV cause in children?
Chickenpox
What happens to the VZV after chickenpox has occurred?
It lays dormant in the sensory nervous system
What part of the sensory nervous systems does VZV lat dormant in?
The geniculate, trigeminal or dorsal root ganglia
How long can VZV lay dormant for?
Decades
What will happen when VZV is reactivated?
It will flare up in a single dermatome segment
How does VZV affect the dermatome?
It travels down the affected nerves over a period of 3-4 days, causing perineural and intraneural inflammation
What are the most commonly affected areas by shingles in immunocompetent patients?
- Thoracic nerve roots
2. Ophthalmic division of CN V
What is the danger of ophthalmic shingles?
It can progress to involve the entire eye
What things are associated with flare-ups of VZV causing shingles?
- Ageing
- Immunosuppressive illness
- Psychological or physical trauma
What age are most patients with shingles?
Over 50
What immunosuppressive illnesses can lead to flare up of shingles?
- HIV
- Hodgkin’s lymphoma
- Bone marrow transplants
What phases can shingles be divided into?
- Pre-eruptive phase
- Eruptive phase
- Chronic phase
What happens in the pre-eruptive phase of shingles?
- No skin lesions
- Burning, itching or paraesthesia in one dermatome
- Systemic symptoms
What systemic symptoms can be present in the eruptive phase of shingles?
- Malaise
- Myalgia
- Headache
- Fever
What happens in the eruptive phase of shingles?
- Skin lesions appear
- Acute neuritic pain
How do shingles lesions first appear?
As a patch of eryhtematous, swollen plaques with clusters of small vesicles affecting only one dermatome
What happens to shingles lesions over 7-10 days?
Crusting and drying
How long can resolution of shingles take?
14-21 days
When are shingles lesions no longer infectious?
Once the lesions have dryed
Who has a longer and more extensive eruptive phase of shingles?
Elderly and immunocompromised patients
What can happen as a result of shingles in older and immunocompromised patients?
- Haemorrhagic blisters
- Skin necrosis
- Secondary bacterial infections
What happens in the chronic phase of shingles?
Persisting or recurring pain lasting 30 days+ after acute infection or after all lesions have crusted
What percentage of shingles cases are ophthalmic?
10-20%
What is the biggest risk of ophthalmic shingles?
It can be a threat to sight
What are the features of ophthalmic shingles?
- Lesions of the orbit or globe within 3 weeks of rash
- Rash may show Hutchingson’s sign
- Red eye
- Decreased visual acuity
- Epiphora
- Photophobia
- Forehead tenderness
What is Hutchingson’s sign in shingles?
The tip of the nose is affected
What does tip of nose involvement in shingles mean?
There is involvement of the nasociliary branch of the trigeminal nerve
What does the nasociliary branch of the trigeminal nerve also supply?
The globe
How is shingles diagnosed?
Clinically based on the dermatomal lesion
If shingles is suspected and there is extension beyond one dermatome what will the patient need to be investigated for?
Immunodeficiency
What are the differentials for shingles?
- Contact dermatitis
- Herpes simplex
- Eczema herpeticum
- Atopic eczema
- Impetigo
What are the general management precautions in shingles?
- Keep rash clean and dry
- Cover if possible
- Avoid work/school if lesions are not dry or cannot be covered
What topical medications are used in shingles?
- Topical antibiotic if secondary bacterial infection
- Topical antiviral is not recommended
What oral medication is used for shingles?
Oral antiviral e.g. acivlovir
When should oral aciclovir be started for shingles?
Within 72 hours if any of:
- Over 50
- Non-truncal involvement
- Moderate to severe pain
- Ophthalmic involvement
- Immunocompromised
If aciclovir cannot be started within 72 hours for shingles what should be done?
Consider starting up to 1 week after onset especially if at risk of complications
What are the first line analgesics for pain caused by shingles?
Paracetamol and NSAIDs
What are the second-line analgesics for shingles?
- TCA’s
- Gabapentin
- Pregabalin
- Steroids
- Opioids
What are the additional treatment options for intraocular involvement of shingles?
- Ocular lubricants
- Cycloplegics
- IV antivirals
- Topical steroids
- Intravitreal antiviral therapy
What are cycloplegics used for in intraocular shingles?
Pain relief
When may IV antivirals be required in intraocular shingles?
- Retinitis
- Choroiditis
- Optic neuritis
What is the most common complication of shingles?
Post-herpetic neuralgia
What is post-herpeticum neuralgia?
Chronic pain along the cutaneous nerves and sometimes distortion of sensation
What are other general complications of shingles?
- Skin complications
- Ramsay Hunt Syndrome
- Bell’s Palsy
- Meningitis or encephalitis
- Disseminated zoster
What are the potential skin complications of shingles?
- Scarring
- Pigmentation
- Secondary bacterial infection
What is Ramsay Hunt Syndrome?
A syndrome of; shingles lesions in the ear, facial paralysis, and associated hearing and vestibular symptoms
When does disseminated zoster occur?
Mainly In Immunocompromised patients
What can disseminated zoster lead to?
- Pneumonia
- Encephalitis
- Hepatitis
What are the potential complications of ophthalmic shingles?
- Ocular complications
- Lid complications
- Long-term complications
What are the potential ocular complications of ophthalmic shingles?
- Pain
- Anterior uveitis
- Keratitis
What are the potential lid complications of shingles?
- Ptosis
- Trichiasis
- Scarring of the skin
What are the potential long-term complications of ophthalmic shingles?
- Poor sensation of cornea
- Poor motor function of the eyelid
