Fungal infection in the immunocompromised...
Transcript of Fungal infection in the immunocompromised...
Dr Kirsty Dodgson
Fungal infection in the immunocompromised patient
Aims
• Discuss different types of fungi
• Overview of types of clinical infections
• Clinical Manifestations
Fungus
• Includes – Moulds
• Aspergillus • Fusarium • Dematiaceaous moulds e.g. Exophiala • Mucoraceous moulds e.g. Rhizopus
– Yeasts • Candida • Pneumocystis • Cryptococcus
Epidemiology
• Moulds are everywhere
• We breathe them in constantly
• Soil, vegetation
• Warm moist humid environments
• Neutropenic diet tries to reduce risk
– Crisps
– Pepper
Candida albicans
• Most common species isolated from superficial sites and blood.
• Most pathogenic species.
• Sensitive to most antifungal agents.
Non-albicans Candida species
Many different species, very heterogeneous.
Generally:
• Increasing frequency- multifactorial explanation.
• Probably less pathogenic than C. albicans.
• Often more resistant than C. albicans.
Changing Epidemiology
• ↑ing aggressive therapy, leads to more susceptible patients.
• Ageing population—more susceptible patients
• Use of prophylactic fluconazole leads to decrease in susceptible sp (e.g. albicans) and replacement with resistant sp (e.g. glabrata).
Skin and mucosa
• Asymptomatic colonisation
• Cutaneous candidiasis
• Chronic mucocutaneous candidiasis
• Oesophagitis
• Onychomycosis
• Oropharyngeal candidiasis
• Vulvovaginitis
Oesophagitis
Thrush
• Assocoiated with decrease in normal flora
• Watch for recurrent cases
• If occur perform ID and susceptibilities
Invasive Candidiasis
• Candidaemia
• Intravascular Catheters
• Disseminated candidiasis
Hepatosplenic Candidiasis
• Within the four overlapping forms of invasive candidiasis, there is a distinct clinical picture that has been given a variety of names:
• Chronic Disseminated Candidiasis (CDC)
• Hepatosplenic Candidiasis,
• Hepatic Candidiasis
• and Granulomatous Hepatitis.
• However, the other terms are equally valid.
HS Candidiasis
• Interestingly this is a condition that affects almost exclusively patients undergoing remission induction chemotherapy or bone marrow transplantation for acute leukemia
HS Candidiasis
• Another remarkable aspect of this condition is that it manifests only on recovery from prolonged periods of neutropenia.
• The other near constant finding is one of a group of abdominal symptoms.
• Right upper quadrant tenderness, hepatomegaly, abdominal distension, nausea, vomiting and diarrhoea occur with variable frequency.
HS Candidiasis
• Liver Function Tests. One of the most consistent biochemical findings in hepatosplenic candidiasis is a marked elevation on serum alkaline phosphatase.
• White Blood Count. Another commonly reported finding among patients with CDC is rebound leukocytosis
• Unfortunately, these laboratory changes are very similar to those found in cases of GVHD and sepsis-related cholestatic liver disease, thus confusing the diagnosis
Deep Organ Candidiasis
• Abdomen (Peritonitis)
– Peritoneal Dialysis-related Candida Peritonitis – Gut-injury Related Candida Peritonitis
• Bone & Joint Candidiasis
– Candida Osteomyelitis
Candida Arthritis
• Brain & Nerves (CNS candidiasis)
– Neurosurgery-related CNS candidiasis
• Eye (Endophthalmitis) Gallbladder (Biliary Candidiasis) Heart (Cardiac Candidiasis) Lung (Candida Pneumonia) Kidney & Bladder (Urinary Candidiasis)
– Fungus Balls in Urinary Tract Asymptomatic Funguria
• Liver & Spleen (Hepatosplenic Candidiasis) • Pancreas (Pancreatic Candidiasis)
Pneumocystis Jiroveci Pneumonia
• Normal flora in healthy competent individuals
• Normally seen as a reactivation in immunocompromised patients
• Traditionally an AIDS defining illness but seen in any immunocompromised pt
• Haematology, oncology and solid organ transplant pts
• Previously Pneumocystis carinii (PCP)
PJP
• Main symptom, exertional dyspnoea
• Marked desaturation
• Its actually a fungus
• Send deep samples for PJP PCR
• Sputum not ideal but better than nothing
• BAL is the gold standard
PJP
PJP Rx
• Treat with Septrin HD • Atovaquone suspension - However, oral atovaquone
has limited and unpredictable bioavailability • Dapsone with trimethoprim - dapsone is given
intravenously or occasionally in nebulised form in the treatment of PCP.
• Clindamycin with primaquine (unlicensed use in the UK)
• Aerosolised pentamidine isetionate is no longer recommended because it is associated with increased frequency of relapse
• Must receive 21 days total treatment
Crytococcus
• Characteristic features:
• Yeast
• forms capsule (seen on india ink stain)
Cryptococcus neoformans
Cryptococcus
• 34 species in the genus
• C. neoformans only one of real importance though case reports of other sp causing disease.
• 2 varieties exist: C. neoformans var neoformans and var gattii
Cryptococcus
var neoformans
• found worldwide
• pigeon droppings
• soil
• Serotypes A, D & AD
var gattii
• Tropical and subtropical
• eucalyptus trees
• Serotypes B & C
Cryptococcus
Disease
Organism inhaled-usually no or mild symptoms. pneumonia rare even in immunocompromised
Meningitis-strongly neurotropic often subacute onset in immunocompetent
Immunocompromised-HIV, transplant
Cryptococcus
Diagnosis
• Microscopy of CSF
• Culture-CSF, Blood
• Anitgen-Blood, CSF
Aspergillus
• Most common mould infection but not all mould infections are aspergillus
• Diagnostics are poor so clinical diagnosis is key
• Fungi are angioinvasive so blood/sputum are rarely positive even by PCR
• Consider B-Glucan and galactomannan based on local policy
Aspergillus
Gram Stain
Sites of Infection
Categories Sites Involved
Colonization Sinuses, lungs
Allergic bronchopulmonary aspergillosis Sinuses, lungs
Pulmonary aspergilloma Pre-existing lung cavity
Invasive aspergillosis
- Pulmonary aspergillosis 1
- CNS aspergillosis - Sinonasal aspergillosis - Osteomyelitis - Endophthalmitis - Endocarditis - Renal abscesses - Cutaneous
Others
- Cutaneous: burns, post surgical wounds, IV insertion sites, etc. - Otomycosis - Exogenous endophthalmitis - Allergic fungal sinusitis - Urinary tract fungus balls
1This is the most common site of primary invasive aspergillosis.
Aspergilloma
• Colonise pre-existing cavities
• May be excised as can erode through and cause haemoptysis
Invasive Apergillosis
Invasive Apergillosis
18 mo girl with leukaemia
Other Moulds
• Zygomycetes
– Causes mucormyosis
– Rhinocerebral mucor, high mortality
• Fusarium
– Disseminated infection
THE
END