Date post: | 21-Jul-2015 |
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Health & Medicine |
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DR SUNIL NAGAR
MBBS : FCCM: DTCD
Invasive fungal infections have increased significantly in past decades due to
aging population with life sustaining therapies like renal dialysis
broad spectrum antimicrobial therapy and invasive medical devices
bone marrow transplantation and solid organ transplantation
chemotherapy for malignancies
HIV / AIDS
Require impairement of host immunity to cause serious infection
Yeasts
- candida spp. (albicans, tropicalis, parasilosis, krusei, glabrata, lusitaniae, etc.)
- Cryptococcus neoformans
Filamentous fungi
- Aspergillus spp. (fumigatus, niger, flavus)
- Zygomycetes (Rhizopus, Mucor, Rhizomucor, Absidia) - Fusarium spp.
- Penicillium spp. (marneffei)
- Pseudallescheria boydii (Scedosporium apiospermium)
Invasive Candida infections ; 4th most common nosocomial blood stream infection in developed countries with mortality approaching 40% in line related candidemia.
Species of candida isolated in blood stream infection
C. albicans 54%
C. glabrata 16%
C. parapsilosis 15%
C. tropicalis 8%
C. krusei 2% and other candida spp. 5%
Increasing incidence of candida non albicans
Candida parapsilosis is a/w central line and TPN
Candida krusei resistance to fluconazole and candida lusitaniaeresistant to amphotericin makes it important to identify the species.
Inspite of recent advances in antifungal medications the response rate remains suboptimal.
RISK FACTORS:
NON NEUTROPENIC : mainly related to barrier breakdown, change in colonization Acute renal failure
TPN
Prior surgery specially GI
Indwelling catheters
Broad spectrum antibiotics
Diabetes
Burns
Mechanical ventilation
Steriods
NEUTROPENIC – related to above plus immune cell suppression, Bone marrow transplant, solid organ transplant and underlying malignancy.
Microbiology methods
Recovery of fungal species from sterile sites (eg. Blood, peritoneal fluid) is diagnostic.
Recovery from multiple non sterile sites is highly s/o fungal infection in the at- risk patient.
But blood culture is positive in less than 50% of patients
Longer replication time cause longer time to interpret this results.
Unable to differentiate colonization from true infection.
May be negative for certain fungal specimen
May require invasive specimen.
Rapid diagnostic tools:
Galactomannan – identifies aspergillus only, false positive with B-lactum antibiotics, low sensitivity in solid organ transplants, no definitive cutoff value
Betaglucan – candida spp. and aspergillus only. False positive are common in patients on albumin , immunoglobulin, on dialysis, etc
PNA FISH – candida albicans and candida glabrata. Requires positive cultures.
Blood culture
Sens 50%, spec 100%
(13)-β-D-glucan
Sens 70%, spec 87%
PCR
Sens 90%, spec 100%
Fever >3 days and progressive sepsis with multi-organ failure despite broad-spectrum antibacterial therapy.
Invasive candidiasis related cutaneous lesions.macronodular rash frequently confused with drug allergies. A biopsy of deeper layers of skin particularly the vascularized areas and dermis is important.
Ophthalmic lesions (Candida endophthalmitis)a fundoscopic evaluation for the presence of Candida endophthalmitis should be performed in patients with candidemia.
• 110 ICU admission, IPA by EORTC/MSG criteria
• 1/3 hematological malignancy interpret with care
• BAL GM probably useful; Serum GM probably not
AJRCCM . 2008;177: 27-34.
36/1756 patients (2%)
20 IPA (defined as “pneumonia”)
14 colonised
Mortality Colonisation 50%
IPA 80%
127 of 1850 (6.9%) consecutive medical ICU admissions with IA or
colonisation (micro/histol).
89/127 (70%) did not have haematological malignancy
67/89 proven/probable IA
33 of 67 (50%) COPD
Mortality 80% (Predicted 48%)
AJRCCM. 2004;170: 621
Steroids (odds ratio = 4.5)
Prolonged corticosteroids treatment prior to ICU
Steroid treatment with a duration of 7 days
Immunosuppressive therapy
Chronic obstructive pulmonary disease (odds ratio = 2.9)
HIV
Severe burns
Prolonged stay in the ICU (>21 days)
Malnutrition
Post–cardiac surgery status
Liver cirrhosis
Solid-organ cancer
Compensatory anti-inflammatory response syndrome
Monocyte/macrophage deactivation
Neutrophil deactivation
HLA-DR antigen expression
Loss of antigen-presenting capacity
synthesis of pro-inflammatory cytokines
Pulmonary colonisation prior to ICU
Lobectomy, PM for unexpected cardiac death
30/74 (41%) patients with Aspergillus species
Environmental contamination
High concentration of air-bourne spores
Lass-Florl et al. BJH. 1999; 104:745-7
Colonisation or IPA?
172 patients, Belgium ICUs, 7 years
89 colonisation
83 IPA (EORTC/MSG criteria)
Poor positive predicative value for IPA
CT
Frequently absent
Halo sign, air crescent sign and nodules much more common in neutropenic patients
Difficult to interpret with ARDS
PCR
Not evaluated in critically ill patients
Biopsy
Gold standard
Difficult!
THE PLATELIA™ ASPERGILLUS EIA IS AN IMMUNOENZYMATIC SANDWICH MICROPLATE ASSAY FOR THE DETECTION OF ASPERGILLUS GALACTOMANNAN ANTIGEN IN SERUM
Helpful in early detection of IPA
High risk patients
Pulmonary infiltrates and fever, not responding to appropriate antibacterial agents
± some concern that Aspergillus may be a diagnostic possibility
Recent unidentified case which died
Isolation of Aspergillus from respiratory tract
Choice of agents depends on
Patient on previous azole prophylaxis
Culture results and local fungal sensitivity
Colonization
Renal or liver disease
Presence of drug-drug interactions
Presence of immunosuppression
Site of disease eg. urine
IDSA recommendations but little evidence in critically ill
Voriconazole
Hepatotoxicity and nephrotoxicity
IV formulation – cyclodextran
Substrate and inhibitor CYP2C19, 2C9 and 3A4
bioavailabity with fat – requires empty stomach
Lipid preparations of Amphotericin B
Less nephrotoxic than deoxycholate
Eichinocandin
Salvage therapy
Combination
Early and appropriate
Mortality (after +ve blood culture)
Day 0 – 15%
Day 1 – 24%
Day 2 – 37%
Later – 41%
A delay in diagnosis will unfortunately result in a delay in initiation of antifungal therapy, which is a/w increased mortality.
Therefore, in the patient with suspected Candida infection, treatment may need to be initiated on the basis of individual patient factors before a definitive diagnosis is made
Species Fluconazole Voriconazole Flucytosine Amphotericin B Echinocandins
C. albicans S S S S S
C. glabrata S – DD to R S – DD to R S S to I S
C. tropicalis S S S S S
C. parapsilosis S S S S S to R
C. krusei R S I to R S to I S
C. lusitaniae S S S S to R S
CID (2009) 48:503–35
Retrospective cohort analysis in patients with candidemia.
Delay in empiric Rx of candidemia till after blood cultures turn positive resulted in higher mortality.
SHOULD A CENTRAL VENOUS CATHETER BE REMOVED ONCE CANDIDEMIA IS CONFIRMED?
Practice guidelines indicate that all central venous catheters should be removed once candidemia is
confirmed .
Of note is that a recent randomized controlled trial and other studies
question the benefit of early removal of central venous catheters in the onset of candidemia for some selected
patients.
24 year old female
Psoriasis with arthropathy
Obesity (110kg)
Admitted to ICU
Methorexate 10mg weekly
1. H1N1 pneumonitis
2. ARDS
3. Pancytopenia
4. Severe sepsis
Persistent sepsis
Respiratory failure (consider for NIV)
Treated with broad-spectrum antibiotics
Identify Candida tropicalis from airways
Identify Candida tropicalis from urine
Day 7Fluconazole 400mg daily
Day 14Caspofungin 70mg then 50mg
Day 20 Ambisome 3mg/kg
Day 53RIP
27 year old female
Known asthmatic
increasing SOB, wheeze and cough
NoPMHx (no DM)
Ex-smoker
Bronchospasm and tachycopnea
Mild tachycardia and normotension
CXR Hyper-expanded but clear lung fields
Responded to nebs
Clarithromycin 500mg BD (penicillin allergy)
Prednisolone 40mg od
Decompensation
ICU - Intubation and MV
Resistant bronchospasm (sedation, muscle paralysis, ketamine and Sevoflurane)
Day 2 - persistent high grade fever
Broad spectrum antibiotics and active cooling
Surveillance
Aspergillus fumigatus
CXR
widespread airspace infiltrates (ALI)
Bronchoscopy and BAL
Culture positive for Aspergillus fumigatus.
No evidence of bacteria growth or acid-fast bacilli.
Serum Aspergillus PCR +ve.
Voriconazole (loaded then 4mg/Kg bd) then to PO
Continued for 6 months (Asp IgG 26)
with
Caspofungin 70mg then 50mg for 30 days
Retrospective Day 0 IgG + IgE to Asp –ve
Day 8 Aspergillus IgG 148 mgA (0-40)
Extubated on day 25
CT (day 31) widespread cavities, ground glass opacity and bronchiectasis
Environmental cultures –ve
No immune defect found
?Systemic antifungal therapy should be strongly
considered, especially in a patient who is at high risk for
disseminated fungal infection, if:
•Fever persists despite antibacterial agents and negative
blood cultures
•High-grade funguria occurs in the absence of a bladder
catheter
•Funguria persists after removal of a bladder catheter
•Fungus is cultured from at least two body sites
•Visceral fungal lesions are confirmed
Candida and Aspergillus increasingly recognised as ICU pathogens
Increased morbidity and mortality
High index of suspicion
Diagnostic strategy (clinical, radiology, lab)
Treatment is complicated
ADR, interactions
The earlier the administration of antifungal treatment the lower the
mortality