Infective lung disease

Question 1

Infective lung diseases include:

Answer 1

• UPPER (URTI) AND MIDDLE RESPIRITORY INFECTIONS (most common) • Rhinorrhoea (runny nose)
• Croup, Epiglottitis, Bronchiolitis
• Lower Respiratory Tract Infections (LRTI) • PNEUMONIA
• PULMONARYTUBERCULOSIS • FUNGALDISEASE
• LUNGABCESS

Question 2

Pneumonia clinical presentation

Answer 2

• Fever and/or chills
• Cough (with or without sputum production)
• Tachypnoea and/or dyspnoea
• Tachycardia or bradycardia
• Wheezing (whistling noise)
• Rhonchi (coarse rattling sound)
• Rales (fine crackles)
• Sternal or intercostal retractions • Dullness to percussion
• Decreased breath sounds
• Pleurisy
• Cyanosis
• Rash
• Acute respiratory distress

Question 3

Pneumonia patholgenesis

Answer 3

Inhalation
Aspiration
Haematogenous

Question 4

What is Pneumonia

Answer 4

• Classified by infecting organism
• Organism dictates treatment
• Acute lung infection; cause: – Bacteria
– Viruses
– Fungi
– Parasites
• Inflammation within & around alveolar tissues (consolidation)
• Common aetiologic agents:
– Streptococcus pneumoniae (b)
– Mycoplasma pneumoniae (b)
– Haemophilus influenzae (b)
– Staphylococcus aureus (b)
– Influenza A & B (v)
• Pneumonitis = inflammation of lung parenchyma caused by a chemical or radiation therapy

Question 5

Clinical diagnosis for pneumonia

Answer 5

• Suggestive signs & symptoms
• Microbiologic testing (Blood / Sputum) • CXR or other imaging techniques
• Bronchoscopy

Question 6

Pneumonia CXR

Answer 6

• Most common cause of solitary airspace filling
• Opacity almost any shape
• Cavitation & pleural effusion are distinct features
• Widely used
• Patterns of pneumonia on CXR typically poor predictor
• Diagnosis compounded by preexisting lung disease e.g. emphysema
• Role of CXR
• Establish presence of pneumonia
• Determine location
• Determine extent
• May identify predisposing conditions e.g. bronchial carcinoma
• Identify associated complications e.g. pleural effusion
• Satisfactory to follow response to treatment
• Role for CT in more complex or slow resolving cases

Question 7

Radiographic patterns of infective pneumonia

Answer 7

• Basic pattern is that of consolidation
• Pneumonias traditionally divided (classified) according to radiographic appearances (patterns of distribution):
• Lobar pneumonia
• Bronchopneumonia (segmental)
• Interstitial pneumonia
• Spherical pneumonia (round or nodular)
• Cavitary
• Limited differential diagnosis value
• Same organisms can produce several patterns
• Pattern partly dependent upon integrity of host’s defenses
• Patterns overlap in individual patients

Question 8

Treatment for pneumonia

Answer 8

• Treatment is based on the infecting organism • Bacterial infections treated with antibiotics
• Match the organism being treated
• Usually treated orally
• Administered IV if case is severe
• Viral infections can’t be treated with antibiotics
• Fluids and rest also advised
• Physiotherapy treatment useful in persistent cases

Question 9

Infective lung disease CT

Answer 9

• To suggest causative pathogens
• Exclude non-infectious pneumonia
• Reveal underlying diseases
• Suspicious round opacification
• Severe or complex pneumonia
• Pneumonia in immunocompromised patients • Pneumonia intractable to antibiotics
• Recurrent/non-resolving pneumonia

Question 10

Infective lung disease NM

Answer 10

• FDG PET/CT and 99mTc-HMPAO-leukocyte scintigraphy for characterizing inflammatory, infectious disease & malignancy
• FDG-PET low specificity but huge potential when combined with other imaging
• Increasing clinical use for TB and HIV associated infections
• Not routine in Australia

Question 11

TB Treatment

Answer 11

• Course of oral medication
• Cocktail of 4 different drugs
• Taken over a period of at least 6 months
• These drugs can produce side effects • Nausea or vomiting
• Jaundice
• Unexplained fever or tiredness
• Tingling or numbness of hands or feet • Joint pains
• Skin rash, itching skin or bruising
• Visual changes

Question 12

Other imaging uses

Answer 12

• NM – VQ scans show defects with pneumonia • MRI – Ventilation study
• US – Guided pleural drainage / aspiration.

Question 13

Pulmonary tuberculosis

Answer 13

Primary infection:
• Located anywhere in lung
• Large or small
• Cavitation is uncommon
• Possiblelymphnodeenlargement
• Possible pleural effusions

Post Primary:
• Commonly located in upper lobe
• Large lesion with potential smaller ones
• Cavitation is more common
• Possible enlargement of hilar lymph nodes

Predisposing factors include:
• Contact with TB • Elderly
• Infants
• Smokers
• Environment/socioeconomic

Symptoms:
• Asymptomatic

Differential:
• Pneumonia
• Lung cancer
• Non-tuberculous mycobacteria
• Sarcoidosis