5.3. Fungal Lung Infections -

5.3. Fungal Lung Infections

Definition

Fungal lung infections occur when pathogenic fungi infect lung tissue, usually in immunocompromised individuals. Most common types include:

Pneumocystis jirovecii pneumonia (PCP) – classically in HIV/AIDS

🎯 EXAM ANCHOR – PCP (PARA)

Pneumocystis jirovecii pneumonia (PCP) classically occurs in HIV/AIDS
Causes hypoxia with relatively mild auscultatory findings
CXR/CT shows diffuse ground-glass opacities

📌 PARA commonly asks:

Which opportunistic infection causes ground-glass opacities in patients with HIV?

Invasive aspergillosis – transplant, neutropenia

🎯 EXAM ANCHOR – INVASIVE ASPERGILLOSIS (PARA)

Occurs in neutropenia, transplant, chemotherapy
Rapidly progressive and life-threatening
Causes fever, chest pain, haemoptysis

📌 PARA commonly asks:

Which patient group is most at risk of fungal lung infections?

Chronic pulmonary aspergillosis (CPA) – post-TB, COPD, sarcoidosis

🎯 EXAM ANCHOR – CHRONIC PULMONARY ASPERGILLOSIS (CPA)

Occurs in patients with pre-existing lung cavities
Common after TB, COPD, sarcoidosis
Causes chronic cough, weight loss, haemoptysis

📌 PARA commonly asks:

Which fungal lung disease occurs in patients with post-TB lung cavities?

Allergic bronchopulmonary aspergillosis (ABPA) – in asthma/CF patients

🎯 EXAM ANCHOR – Allergic bronchopulmonary aspergillosis (ABPA)

Allergic, not invasive fungal disease
Occurs in asthma or cystic fibrosis
Associated with raised IgE and eosinophilia

📌 PARA commonly asks:

Which fungal lung condition is an allergic reaction rather than an infection?

🛡️ Causes (at-risk groups)

🧠 Mnemonic: I’VE HAD FUN

Immunocompromised (e.g., HIV/AIDS, chemo)
Ventilated ICU patients
Existing lung disease (e.g., CF, COPD)
Haematological malignancy
Anti-rejection drugs (transplants)
Diabetes mellitus
Fungal exposure (compost, soil)
Undernutrition
Neutropenia

🎯 EXAM ANCHOR – CORE CONCEPT

Fungal lung infections occur primarily in immunocompromised patients
Often unresponsive to standard antibiotics
May be invasive, chronic, or allergic

📌 PARA commonly asks:

Which patient group is most at risk of fungal lung infections?

🔬 Pathophysiology

Fungal spores inhaled → evade innate immunity → infect alveoli or bronchi → inflammation ± necrosis ± cavitation.

🔍 Clinical Features

🧠 Mnemonic: FUNGAL

Fever
Unexplained weight loss
Night sweats
Gasping for air (progressive SOB)
Atypical chest symptoms (dry cough, haemoptysis)
Lung infiltrates unresponsive to antibiotics

Investigations

Investigation	Relevance
CXR / HRCT Chest	Ground-glass opacities (PCP), cavitations (aspergillosis)
Serum β-D-glucan	Fungal marker (not specific)
Galactomannan (serum/BAL)	Specific for aspergillus
Sputum culture / BAL	Direct microscopy and PCR
HIV test	Always check in PCP
IgE, eosinophils, Aspergillus IgG	If suspecting ABPA/CPA

🎯 EXAM ANCHOR – IMAGING PATTERNS

Ground-glass opacities → PCP
Cavitation / fungal ball → aspergillosis
Imaging often guides diagnosis

📌 PARA commonly asks:

Which fungal infection is associated with cavitating lung lesions?

🎯 EXAM ANCHOR – DIAGNOSTIC TESTS

β-D-glucan suggests fungal infection (non-specific)
Galactomannan is specific for aspergillus
BAL may be required for diagnosis

📌 PARA commonly asks:

Which test is most specific for invasive aspergillosis?

💊 Management (Trust / BTS guidance based)

Infection Type	First-line Management
PCP (Pneumocystis)	High-dose co-trimoxazole ± steroids if hypoxic
Invasive aspergillosis	IV voriconazole or isavuconazole
ABPA	Oral steroids + itraconazole
CPA	Long-term antifungal (e.g., itraconazole) ± resection

🧠 Monitor LFTs + drug levels

🎯 EXAM ANCHOR – MANAGEMENT PRINCIPLE

Antifungal choice depends on organism and immune status
PCP → co-trimoxazole
Aspergillosis → azole antifungals

📌 PARA commonly asks:

Which antifungal treatment is first-line for Pneumocystis jirovecii pneumonia?

🚩Red Flags / Complications

Respiratory failure
Disseminated fungal sepsis
Cavitation + haemoptysis
Pneumothorax in PCP
Treatment resistance

🎯 EXAM ANCHOR – RED FLAGS

Haemoptysis + cavitation
Rapid deterioration in immunocompromised patient
Failure to respond to antibiotics

📌 PARA commonly asks:

When should fungal lung infection be suspected in pneumonia?

📅Follow-Up

Monitor response with serial imaging (CT)
Antifungal duration varies: 3–6 months+
ABPA: long-term IgE + eosinophil monitoring

🔎 Key PARA Exam Traps

💡 Think fungal infection in immunocompromised patients: Steroids, chemotherapy, transplant, HIV, neutropenia

💡 Aspergillus is the most common fungal lung pathogen: Especially in chronic lung disease or immunosuppression

💡 Haemoptysis + cavitation = think Aspergilloma: Fungal ball in a pre-existing cavity (e.g. TB, bronchiectasis)

💡 ABPA ≠ invasive fungal infection: Allergic reaction → asthma, bronchiectasis, raised IgE

💡 Normal sputum cultures do NOT exclude fungal infection: Diagnosis often requires CT ± serology ± BAL

💡 Upper lobe cavitation is not always TB: Consider fungal infection if cultures negative

💡 Invasive aspergillosis = medical emergency: Fever, chest pain, haemoptysis in neutropenic patient

💡 Eosinophilia suggests allergic fungal disease: Not typical of invasive infection

💡 Antibiotics failing → rethink diagnosis: Consider fungal, TB, malignancy

🔎 Last updated in line with BTS Fungal Lung Disease Guidelines & NHS Trust Protocols
Published: June 2021 • Last updated: August 2023

PARA-aligned, reviewed February 2026

🔒 PASSMAP ensures all content is NICE-aligned and reviewed for Physician Associate Registration Assessment (PARA) success.