CP3 fungal pathogens Flashcards
What are 4 types of fungal pathogens?
dermatophytes
Malassezia species
Candidia species
Aspergillus species
What are two growth forms of fungi?
Hypha (moulds)
Yeasts
Where are fungi found?
On decaying organic matter (known as saprophytes)
On plants
On animals
What are 3 types of infection caused by fungal pathogens?
Superficial infection (skin hair and/or nails)
Subcutaneous infection (usually following traumatic implantation)
Systemic (affecting deep seated organs)
What are dermatophytes and where do they come from?
Group of moulds that cause disease in the hair skin and nails. Come from geophillic (soil), zoophilic (animals) and anthropophilic (other humans) sources.
What fungal pathogen caused inflammatory tinea infections?
Trichophyton interdigitale
What is the medical term for a fungal disease?
Tinea ______ (blank filled in with body part)
What are 5 examples of dermatophyte infection?
Athletes foot
Fungal nail disease
Jock itch
Ringworm
Scalp ringworm
What is the incidence of fungal nail infection?
5-25%
Who is most likely to suffer from fungal nail infection?
Elderly
Who is most likely to get athletes foot?
Adults and sportsmen
Who is most likely to get scalp ringworm?
Prepubertal children - 6%
What are presentations of athlete’s foot?
Uni or bilateral itching, flaking and fissuring of skin of foot
What can occur secondary to athletes foot?
Hyperhidrosis and toe nail infection
What is a typical pathogen that causes athletes foot?
Trichophyton rubrum
What is the medical term for athletes foot?
Tinea pedis
How is tinea ungumium categorised?
Healthy
Distal-lateral infection
Superficial white
Proximal
Total dystrophic
Who is more likely to get tinea cruris (jock itch)?
Men
What are symptoms of jock itch?
Itching, scaling, erythematous plaques, satellite lesions (sometimes) in the groin which may extend to bum, back and lower abdomen
What fungal pathogens can cause jock itch?
Trichophyton rubrum or Trichophyton indotineae
What are the signs/symptoms of tinea capitis athropophilic and zoophilic?
Anthropophilic - Range from slight inflammation, scaly patches with alopecia, “black dots” to severe inflammation
Zoophilic - boggy, inflamed lesions
What type of causes are associated with tinea capitis (scalp ringworm)
Anthropophilic and zoophilic causes
What are the symptoms of tinea corporis?
Circular, single or multiple erythematous plaques
What is it called when ringworm invades the follicle?
Majocci’s granuloma
What causes ringworm?
Dermatophytes (both anthropophilic and zoophilic)
What do you treat most dermatophyte infections?
Topical anti fungal treatments if mild e.g. terbinafine, clotrimazole, micronazole
Systemic anti fungal if severe
How do you treat tinea capitis (scalp ringworm)?
NEVER with topical treatment, always systemic oral antifungals e.g. terbinafine, griseofulvin or itraconazole depending on causal species
What is malassezia?
A genus of yeasts
What are examples of malassezia?
M. Sympodialis
M. Restricta
M. Globosa
Malassezia is a part of normal skin flora, where are the highest levels found?
In head and trunk of the body
What disease are caused by malassezia?
Pityriasis versicolour and plays a role in seborrhoeic dermatitis and atopic eczema
What are symptoms of pityriasis versicolour?
Hyper or hypo pigmented lesions
How do you diagnose and treat pityriasis versicolour?
Diagnose with microscopy and treat with topical antifungals like clotrimazole primarily. If unaffective, treat with oral fluconazole or itraconazole
What are candidia?
A genus of yeast
Where is candida found in healthy people?
Mucosal surfaces and the GI tract
What diseases are caused by Candida?
Superficial mucosa diseases e.g. oral and vaginal thrush and occasionally skin disease and keratitis
Systemic diseases
What are some Candida species?
Candida…
… albicans
… glabrata
… parapsilosis
… krusei
What type of oral candidosis is found in younger patients? What causes it?
Acute pseudo-membranous with a low CD4 count
Asthma with steroid inhalers
What type of oral candidosis is found in older patients? What causes it?
Chronic atrophic
Age meaning more susceptible to infection
What are symptoms of the lips in oral candidosis?
Angular cheilitis and chronic hyper plastic oral leukoplakia where lesions may become malignant
Who is most likely to get oral candidosis?
People with HIV/AIDS
People using antibiotics
People with head and neck cancer
Hospitalised patients
Who is affected by candida vulvovaginitis?
70-80% of all women during child bearing years
What are symptoms of candidia vulvovaginitis?
Pruritis, burning sensations with or without discharge and inflammation of the vaginal epithelium which may extend to the labia majora
What percentage of women will suffer recurrent vulvovaginal candidosis?
10%
How many times a year do you have to have vulvovaginal candidosis to be diagnosed with recurrent vulvovaginal candidosis?
4
How is vulvovaginal candidosis diagnosed?
By a positive culture in symptomatic patients
What do you treat vulvovaginal candidosis with in non-pregnant women? What can you use for pregnant women?
Azoles- either orally with fluconazole or topically with clotrimazole pessaries.
Topical treatments ONLY - NO AZOLES!!!
What causes systemic candidosis?
Infection of candida species from colonised skin or muscosal sites, or from the GI tract
What is the most common species of Candida causing systemic candidosis?
Candida albicans
How can you diagnose systemic candidosis?
Blood culture
Who is most likely to get candida oesophagitis?
People with HIV
10-20% of people with oropharyngeal disease
How is Candida oesophagitis diagnoses?
With endoscopy and biopsy
What are symptoms of candida oesophagitis?
Pain (odynophagia) and difficulty upon swallowing/eating (dysphagia)
What is the incidence of candidaemia?
3.3 cases per 1000 ICU admissions
What should you do if a patient is diagnosed with candidaemia?
Remove lines and catheters where possible, start antifungal therapy and check eyes and heart
What are two secondary diseases to candidaemia?
Ocular candidosis- 75% of which cause chorioretinis and 25% cause endophthalmitis
Candidia endocarditis (in 2-3% of cases)
Who is most likely to have candida endocarditis?
IV drug users and those who have undergone valve surgery
What are signs and symptoms of candida endocarditis?
Fever, weight loss, fatigue and heart murmur and vegetations on heart valves
How do you most effectively treat candida endocarditis?
Valve replacement
Who is most likely to get candida UTI?
Women
Diabetics
Damaged/abnormal urinary tracts
ICU patients (usually because of catheters)
What is candiduria?
Isolation of candida from urine
Why are candida UTI’s hard to treat?
Because few antifungals are secreted in urine
What percentage of patient in ICU develop candiduria within 7 days?
22%
What causes candida peritonitis?
It’s a complication of peritoneal dialysis or from a perforation of the bowel during surgery
What are symptoms of candida peritonitis?
Fever, abdominal pain, nausea and vomiting
How is candida peritonitis diagnosed?
By sampling peritoneal fluid and culturing candida
How do you treat candida peritonitis?
Source control and drainage as well as antifungals
How do you treat candida infection?
Determined by each species and their sensitivity and severity by include azoles, echinocandins (e.g. anidulafungin via IV) and liposomal amphotericin B (by IV)
What are aspergillus?
A genus of mould - filamentous fungi
How do aspergillus spread?
By producing airborne spores what are inhaled
What are examples of medically important aspergillus species?
Aspergillus…
… fumigatus
… niger
… flavus
… terreus
What causes aspergillosis?
The body reacts to the presence of aspergillus in the airways
What are 4 reactions in the airways to aspergillus?
- Space occupying/non-invasive infection e.g. aspergilloma
- Allergic reaction
- Chronic infection e.g. CPA
- Invasive infection
What is aspergilloma?
A fungal ball
What can aspergillomas cause?
Break up and cause haemoptysis which can be fatal
Who is likely to get allergic forms of aspergillosis?
Patients with cavities, a Hx of TB, sarcoid or lung surgery
What are symptoms of allergic aspergillosis?
Wheezing, breathlessness, loss of lung function, bronchiectasis
What are clinical signs of allergic aspergillosis?
Airways inflammation, increase total IgE
How do you treat allergic aspergillosis?
With steroids with or without antifungals
Who is susceptible to chronic pulmonary aspergillosis (CPA)?
Those with COPD
What are symptoms of CPA?
Chronic respiratory symptoms like wheezing, cough, breathlessness and chest pain
How is CPA diagnosed?
By CT observing consolidation and cavitation, a positive culture of aspergillus from sputum and BAL and a positive result for aspergillus IgG
Who is susceptible to invasive aspergillosis?
Those with haematological malignancy or have had a stem cell or organ transplant
What are clinical signs of invasive aspergillosis?
Low neutrophil count and angioinvasion of lung tissue, halo and air crescent signs on CT
What is the prognosis for invasive aspergillosis?
Moderate to poor (even with aggressive antifungal therapy)
What are some examples of medication used to treat CPA and invasive aspergillosis?
Itraconazole, voriconazole and amphotercin B
