Infection And Immunology David Taylor Flashcards by Olivia Watkins

Fungi are carbon heterotrophs. What does this mean?

They require preformed organism compounds as carbon sources

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What are fungi? What are they divided into?

Eukaryotic organisms so they have a true nuclei

Divided into yeasts and moulds

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What are dermatophytes?

Moulds
Keratinophilic: associated with infections of the skin nails and hair and get spread through direct contact.
Common symptoms include itching burning and pain

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What is common in the name of dermatophytes??

Tinea
Eg tinea corporis
Tinea cruris

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What is tinea corporis?

Ringworm of the skin

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What is tinea cruris?

Ringworm of the groin

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What is tinea capitis?

Ringworm of the scalp

Cap= scalp!

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Dermatophytes are usually diagnosed visually or by sending nail clippings off for analysis.
What does ring worm look like?

Raised around the edges with a clear area in middle

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What is first line treatment for tinea corporis and tinea cruris?

Topical imidazole
Eg clotrimazole, ketoconazole
Should treat with creams for a further two weeks to ensure it goes away

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If topical treatment fails, or if someone’s immuno compromised or the infection is particularly wide spread, what can we use to treat tinea corporis and cruris?

Terbinafine ORALLY

250mg a day for 4 weeks

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What do we use to treat tinea Capitis? (Ringworm of scalp)

Usually oral treatment is required such as Terbanifine or griseofulvin, PLUS:
Ketoconazole/ selenium sulphide shampoos or terbanafine creams twice weekly

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What organisms is griseofulvin effective against?

What about terbinafine?

Griseofulvin effective against Trichophyton tonsurans, microsporum spp.
Terbinafine effective against Trichophyton tonsurans

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Griseofulvin is only effective against dermatophytes. Why are long courses needed? Who should avoid it?

Long course as it does not persist in keratinous tissue after the end of therapy
Shouldn’t be taken by people with severe liver disease, and systemic lupus erythematosus
Should be avoided in breast feeding
Avoid in pregnancy and for one month after stopping treatment

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What are the main side effects of griseofulvin?

GI side effects
Cognitive effects
Hypersensitivity reactions

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Griseofulvin has many interactions. What are these?

Enhances effects of alcohol
Decreases efficacy of oral contraceptives and coumarins

Needs to be taken with or after fatty foods!

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What is used first line to treat athletes foot?

Imidazole cream
For 2-4 weeks or
Terbinafine cream for 1 week
Undecenoates for 2-4 weeks

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If topical treatment fails for severe athletes foot, what three oral tablets could be taken? (Just say names)

Terbinafine
Itraconazole
Griseofulvin

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Terbinafine can be taken orally or topically. It concentrates in keratinous tissue. When should it be avoided? What are the side effects?

Avoid In pregnancy and liver disease.
Side effects:
GI disturbance
Hepatotoxicity with prolonged therapy
Serious skin reactions

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What species can we commonly find infecting our nails?

Trichophyton rubrum
Epidermiohyton floccosum
Trichophyton mentagrophytes

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Onychomycosis means nails. What’s the most common type of nail infection?

DLSO starts at the top of the nail works down to nail bed

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What’s a good treatment for fungal nails?

Itraconazole pulse therapy
Itraconazole stays in keratin in nails for longer

Can also use itraconazole 200mg daily for 3 months
Could also use terbinafine for 6 weeks to 3 months
Note this is all SYSTEMIC management, taken orally

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We can also use topical treatment for nail infections eg Ticonazole, Amorolfine. When is this appropriate to use?

Topical treatment will only work in mild distal disease in up to 2 nails. White superficial and early DLSO.
Localised distal nail may respond to Ticonazole or amorolfine

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What is pityriasis versicolor?

Colonisation of the stratum corneam (in skin)
Caused by malassezia furfur
Starts at the neck and shoulders, multiple dark patches
Starts around puberty

What can we treat pityriasis versicolor with?

Ketoconazole shampoo
Clotrimazole or ketoconazole creams
Terbinafine cream

If these fail
Oral treatment:
Itraconazole 
Fluconazole 
Relapse is COMMON

Why is oral ketoconazole not really used anymore?

Can cause serious and rapid hepatotoxicity Should only be given under specialist advice Monitor liver function before and 2-4 weeks after treatment then monthly.

What topical therapy can we give for oropharyngeal candida?

First line: Imidazole antifungals eg miconzaole oral gel for 7 days Second line: Polyene antifungals such as nystatin suspension 7 days

What oral therapies can be given for oropharyngeal candida?

Fluconazole 50mg daily for 7-14 days Give it for 14 days if atrophic candidiasis associated with dentures

What fungal organism accounts for 90% of vaginal candidiasis?

Candida albicans

What topical treatments are effective for uncomplicated Vuvovaginal candidiasis?

Clotrimazole, Econazole Miconzaole

What oral treatments do we give for vaginal candidiasis?

Fluconazole (150mg single dose) | Itraconazole (200mg twice daily for one day)

What is cutaneous candidiasis and where is it found?

Cutaneous means anywhere that's wet and moist so is found in folds of the skin, under breast, child's bum. It's a very intense red rash that's itchy and burny and painful

What can we treat cutaneous candidiasis with?

Topical imidazole Oral when severe: fluconazole 50mg daily for 14 days Treat topically in children

What are Arthropods?

Segmented body, appendages, hard exoskeleton made of chitin

What are pediculus humans capitis?

Head lice

What is a nit?

The egg capsule of a head louse The empty shell that's left in the hair after a louse has hatched. Nit does not confirm infestation

What is Dimeticone 4% in a silicone solvent used to treat?

Used for head lice Physical action but is not a physical insecticide, good for patient who don't want to use these Immobilises the lice and disrupts their water regulatory processes First line!!

What us isopropyl myristate cyclomethicone?

Full marks solution Has physical action Disrupts exoskeleton of lice

How is Dimeticone applied?

Applied to dry hair and allowed to dry naturally Left on for 8 hours then washed off Reapplication after 7 days Use with caution in people with asthma and eczema

What causes scabies?

Sarcoptes scabiei A mite Burrows into epidermis commonly in flexures/ creases Papular eruption Really itchy Worse at night and after hot bath or shower Diagnosis through skin scrapings

What is Crusted Norwegian scabies?

``` A hyper-infestation Whitening of the skin, wet lesion, thick and white. Millions of mites Hyperkeratotic crusts Common in immuno compromised patients Secondary infections can be a problem ```

Pharamcists should refer if they suspect dermatitis herptiformis. What is this?

Chronic blistering of the skin, blisters fill with watery fluid Has an appearance similar to herpes but not caused by herpes virus Symptoms relate to gluten ingestion: gluten allergic Associated with oral contraceptive use

What should we treat standard scabies with?

Permethrin Apply it all over the skin but not scalp (but do treat scalp in elderly, immuno-compromised or young) Leave for 8 hours and wash off Can be used in 2 months and over, 2month- 2 years must be under medical supervision Refer if two treatment failures have occurred

A patient has been treated with permethrin for scabies, however three weeks later they're still feeling itchy. Has treatment failed?

No necessarily, can still itch after eradication | Ease with topical emollients like crotamiton cream 10%.

What's an alternative first line treatment to permethrin for scabies?

Malathion | Left on for 24 hours

What unlicensed treatment can be used for Norwegian scabies?

Ivermectin | Blocks the neurotransmission action of GABA

What can we treat Itching with in scabies?

Topical crotamiton or topical hydrocortisone Avoid topical steroids if diagnosis not certain Sedating antihistamines

What's the anthropod that causes crab lice?

Pthirus pubis

How is crab lice spread?

Through direct contact, contact with bed clothes | If caught through sexual contact, consider referral to GUM clinic and all their sexual contacts should be screened too

How should we treat crab lice?

Permethrin or malathion Malathion: suitable for everyone Permethrin: suitable for all individuals over 18 years old unless pregnant or breast feeding. Apply these twice with a weeks gap, assess after one week to se if successful. Should not be used more than once a week and for three consecutive weeks

What's the itching caused by with headlice?

An immune reaction with saliva | May take time to occur

When to refer headlice?

Treatment failure Severe infestation Secondary bacterial infection from itching

Why shouldn't we use chemical insecticides for nits these days?

Due to resistance | Only use if wet coming and physical insecticide haven't worked!!

Scabies: finger webs | Dermatitis hypeformis: back and shoulders

Crablice: coarse hair

How can we treat crab lice in the eye lashes?

Simple eye ointment of permethrin or malathion, apply twice a day

How do we treat harvest mite bite?

Hydrocortisone cream and some repellent eg DEET | This is also good for mosquito bites

What's the disease called that is a risk with tics?

They carry Lymes disease Refer if tic bite seen Initially causes fever, at worse affects heart, joints, other organs, potentially paralysis