- Aspergillus Fumigatus
This is a moulid which affects the lungs both directly and indirectly. It is a systemic opportunist and so typically affects those who are immunocompromised or more susceptible to infection.
– Can indirectly cause Asthma and also Extrinsic Allergic Alveolitis as well as direct pathologies:
– Allergic Bronchopulmonary Aspergillosis (ABPA)
Aspergillus Fumigatus causes type I and III hypersensitivity reactions, which is particularly seen in people with Asthma and Cystic Fibrosis. This leads to acute bouts of inflammation and bronchiectasis.
– It initially causes bronchoconstriction giving asthma symptoms then permanent damage giving bronchiectasis
– Wheeze and Dyspnoea
– Cough with sputum containing fungal hyphae
– Recurrent chest infections
– High resolution CT – shows bronchiectasis
– Radioallergosorbent (RAST) Aspergillus test
– Positive IgG Precipitins
– Raised IgE and eosinophilia
Management – 1st line Oral steroids –> 2nd line Itraconazole
This is when the mould forms a fungal clump within a body cavity.
Risk factors – TB, Sarcoidosis, Lung cancer
Symptoms: Asymptomatic in most people, however can resemble a lung cancer
– Cough with blood, weight loss
Investigations: CXR shows lung cavity, High titres of IgG Aspergillus Precipitins
– CT shows air-crescent sign
Management – Treat with Itraconazole + Amphotericin –> Consider surgical excision
– Invasive Aspergillosis
This occurs in people with a severe neutrophil deficiency. The mould becomes invasive and starts to penetrate the lungs and paranasal sinuses and has a high mortality.
Risk factors: HIV, Leukhaemia, Immunocompromised
Diagnosis: Made by a lung biopsy Treatment: IV Voriconazole + Amphotericin
- Cryptococcus Neoformans
This is a yeast found in bird droppings which is the most common fungal infection of the CNS.
– It is a systemic opportunist which typically causes infections in immunocompromised patients + IVDU
– Usually causes infections in the lung, but most serious infection is meningitis infection in AIDS patients
Symptoms – Commonly seen in patients with AIDS with CD4 count <100cells/mm3
– Meningitis (fever, headache, seizure, vomiting) – Focal neurological deficit
Tests – CT –> shows cerebral oedema
– Lumbar puncture –> CSF has high opening pressure, India ink test positive
– High Lymphocytes, low neutrophils, raised protein, low glucose (therefore atypical)
Management – IV Amphotericin + flucytosine
- Pneumocystis Jirovecci/Carinii
A fungal infection that is an AIDS defining disease, typically causing a pneumonia in HIV positive patients.
Symptoms – Atypical Pneumonia (SOB, dry cough, fever) but very few chest signs
– Can lead to pneumothorax + hepatosplenomegaly and lymphadenopathy
– Gives typical desaturations of SpO2 during exercise
Tests – CXR shows bilateral interstitial pulmonary opacifications
– Sputum culture –> this is stained using the Grocott (silver stain) to identify the fungi
Management – 1st line is Co-trimoxazole –> 2nd line is IV pentamidine
– Prophylaxis with co-trimoxazole is recommended in all patients with a CD4 count of less than 200/mm³
1. Yale Rosen from USA / CC BY-SA (https://creativecommons.org/licenses/by-sa/2.0)