1. Chest p47-55 (Infection) Flashcards
Strep. Pneumoniae (imaging)
Lobar consolidation
Strep. Pneumoniae (trivia) (3)
Favours lower lobe.
Severe in sickle cell pts post splenectomy.
Commonest pneumonia in AIDS pts.
Staph aureus pneumonia (imaging)
Bronchopneumonia - patchy opacities
Staph Aureus pneumonia (trivia) (3)
Often bilateral,
Can make abscesses,
Can spread via blood in endocarditis
Anthrax pneumonia - imaging (3)
Haemorrhagic lymphadenitis,
Mediastinitis,
Haemothorax
Anthrax pneumonia - classic look (2)
Mediastinal widening with pleural effusion,
Setting of bio-terrorism
Klebsiella pneumonia - imaging (2)
“Bulging fissure” from inflammation.
More likely to have pleural effusions, empyema and cavity than conventional pneumonia
Klebsiella - Trivia (2)
Alcoholics and nursing home pts.
Current jelly sputum
Haemophilus - imaging (2)
Usually bronchitis.
Can get bilateral lower lobe bronchopneumonia
Haemophilus - trivia (2)
Seen in COPD and people without spleen
Pseudomonas - imaging (2)
Patchy opacities with abscess formation.
Pleural effusions are common but usually small
Pseudomonas - trivia (2)
ICU pts (or CF/primary cilliary dyskinesia)
Legionella - imaging (3)
Peripheral and sublobar airspace opacity.
Imaging lags behind resolution of symptoms.
Cavitates only if immunosuppressed.
Legionella - trivia (2)
COPD pts.
Seen around bad air conditioners.
Aspiration - imaging (2)
Anaerobes with airspace opacity.
Can cavitate and form abscess.
Aspiration - trivia (4)
Posterior lobes if supine while swallowing.
Basal lower lobes if upright.
May favour right side, like ET tube.
Commonest complication is empyema, which may lead to bronchopulmonary fistula.
Actinomycosis - imaging (2)
Airspace opacity in peripheral lobes.
Can be aggressive and cause rib osteomyelitis or invade chest wall
Actinomycosis - trivia
Commonly dental procedure gone wrong, leading to mandible osteomyelitis and aspiration.
Mycoplasma - imaging (2)
Fine, reticular pattern on CXR.
Patchy airspace opacity with tree-in-bud
Commonest cause of death post bone marrow transplant
Pneumonia, occurs in almost 50% of people after BMT
Graft vs Host disease post BMT (types) (4)
Acute:
- 20-100 days
- Favours extrapulmonary systems (Liver, skin, GI)
Chronic:
- >100 days
- Lymphocytic infiltration of airways and obliterative bronchiolitis.
Post BMT Pulmonary findings (types) (3)
Early neutropenic (0-30 days),
Early (30-90 days),
Late (>90 days)
Early neutropenic post BMT findings (lung) (4)
Pulmonary oedema,
Haemorrhage,
Drug induced lung injury,
Fungal pneumonia (invasive aspergillosis)
Early post BMT findings (lung) (2)
PCP, CMV
Late post BMT findings (lung) (2)
Bronchiolitis obliterans,
Cryptogenic organising Pneumonia
AIDS infections - CD4 >200 (2)
Bacterial infections,
TB
AIDS infections - CD4 <200 (2)
PCP,
Atypical mycobacterial
AIDS infections - CD4 <100 (3)
CMV,
Disseminated fungal,
Mycobacterial
AIDS - focal airspace opacity - DDx (3)
Bacterial infection (strep most common),
Consider TB if low CD4,
Consider lymphoma or kaposi sarcoma if chronic
AIDS - multi-focal airspace opacity - DDx (2)
Bacterial or TB
AIDS - ground glass - DDx (2)
PCP.
Consider CMV if CD4<100
PCP - trivia
Most classic AIDS infection
PCP - imaging (2)
Perihilar ground glass, sparing periphery.
Can have thin walled cysts within the ground glass opacities (30%)
AIDS - flame shaped perihilar opacity (Dx)
Kaposi sarcoma
AIDS - persistent opacities (Dx)
Lymphoma
AIDS - Lung cysts
LIP
AIDS - Lung cysts & ground glass & pneumothorax
PCP
AIDS - hypervascular lymph nodes (2)
Castlemans or Kaposi
TB - types (4)
Primary,
Primary progressive,
Latent,
Post primary (reactivation)
Primary progressive TB - definition (2)
Local progression of parenchymal disease with development of cavitation (at initial site or site of haematogenous spread).
Similar in course to post-primary disease
Primary TB - Progression (7)
- Inhaled bug leads to necrosis.
- Body attacks it, forms granuloma (Ghon focus).
- Nodal expansion (bulky in kids, less common in adults), can calcify (Ranke complex).
- Bulky nodes can cause compression, leading to atelectasis.
- Node may rupture into a bronchus (causing endobronchial spread) or vessel (haematogenous spread –> milliary TB).
- Cavitation is NOT common in primary TB.
- Effusions can be seen, more common in adults.
Primary progressive TB - associations (6)
Uncommon, associated with HIV or immunocompromise:
- transplant,
- steroids,
- jejuno-ileal bypass,
- subtotal gastrectomy,
- silicosis
Latent TB - definition
Positive skin test, negative CXR and no symptoms
Post primary (reactivation) TB - definition (2)
Endogenous reactivation of latent infection.
Happens in 5% of cases.
Post primary (reactivation) TB - anatomy (4)
Classically apical and posterior upper lobe, and superior lower lobe (more oxygen, less lymphatics).
Primary infection tends to show healing, post primary tends to show progression.
Cavity development is key feature of post-primary.
Arteries near the cavity can form aneurysms (Rasmussen aneurysm)
Immune Reconstitution Inflammatory Syndrome (clinical & Rx) (2)
Pt with TB & AIDS doing worse clinically after starting HAART.
Rx = steroids
Pleural involvement with TB (3)
Primary TB - pleural effusion can occur any time, usually 3-6 months, as a hypersensitivity response.
Pleural fluid is culture negative (60%), pleural biopsy then needed for diagnosis.
Post-primary: Pleural effusions are rarer but more often culture positive.
Ghon lesion (2)
Calcified TB granuloma.
sequela of primary TB
Ranke complex (2)
Calcified TB granuloma & calcified hilar node.
healed primary TB
Bulky hilar and paratracheal adenopathy
Kids
TB patterns in HIV (3)
Reactive pattern (cavitations) seen when CD4 >200.
Primary progressive pattern (adenopathy, consolidation, milliary spread) seen when CD4 <200.
TB does NOT usually form lobar pattern in HIV.
Non-tuberculous mycobacterium - types (4)
Cavitary (“classic”),
Bronchiectatic (“non-classic”, “Lady Windermere”),
HIV,
Hypersensitivity pneumonitis (“Hot tub lung”)
Cavitary mycobacterium (3)
Usually caused by MAC (Mycobacterium Avium-intracellulare Complex).
Commonly old, white, male with COPD or chronic lung disease.
Looks like reactivation TB (upper lobe cavitating lesion w/adjacent nodules).
Bronchiectatic mycobacterium (4)
a.k.a. Non-classic or Lady Windermere.
Caused by not coughing.
Favours old, white lady.
Tree-in-bud and cylindric bronchiectasis in the right middle lobe and lingula.
HIV mycobacterium (4)
Seen with CD4 <100
GI infection disseminated in blood. Hepatosplenomegaly.
Mediastinal lymphadenopathy is commonest manifestation.
Frequently mixed with other chest infections, lungs can look like anything.
Hypersensitivity pneumonitis (3)
Hot tub lung.
Aerosolised bugs.
Ill defined, ground glass, centrilobular nodules.
Aspergillus infections - types (3)
Normal immune system.
Immunocompromised.
Hyper-immune.
Aspergillus - normal immune system (2)
Aspergilloma (fungus ball) formed within an existing cavity.
Cavity can be from trauma, prior infection, etc.
Aspergillus - Immune compromised (5)
AIDS or transplant patient.
Invasive aspergillosis.
2 appearances:
1) Halo sign - solid nodule/mass surrounded by ground glass (gg is actually the invasive component)
2) Air crescent sign - thin crescent of air within solid mass, which represents healing as the necrotic lung separates from parenchyma. 2-3 weeks after healing.
May also see peripheral, wedge shaped infarcts in setting of some halo signs
Aspergillus - hyper immune (3)
Asthmatic (long standing) or CF.
ABPA - Allergic Broncho-Pulmonary Aspergillosis.
Upper lobe central saccular bronchiectasis with mucoid impaction (finger in glove)
Mucormycosis (2)
Seen in immune compromised (AIDS, steroids, bad diabetes).
Invasion of mediastinum, pleura and chest wall.
CMV - causes (2)
Reactivation of latent virus after prolonged immunosuppression (e.g. 30-90 days post BMT).
Infusion of CMV positive bone marrow or other blood products.
CMV - imaging
Multiple ground glass or solid nodules.
Measles - imaging
Multifocal ground glass opacities with small nodular opacities.
Measles - trivia
Pneumonia can be before or after skin lesions.
Complications higher in pregnant or immunocompromised
Influenza - Imaging (2)
Coalescent lower lobe opacity.
Pleural effusion is rare.
SARS - imaging
Ground glass opacities, predominantly lower lobe
Varicella - imaging (2)
Multiple peripheral nodular opacities.
Forms small round calcific nodules in healed version.
Varicella - trivia (2)
1 in 6 with skin findings get pneumonia.
Usually kids. Usually immunocompromised (AIDS, lymphoma)
Ebstein Barr - imaging (2)
Rarely affects lung. Can cause lymph node enlargement.
Most common radiographic abnormality is splenomegaly.
Septic emboli (lung) - trivia (5)
Lower lobe predominant (more blood flow).
Can infarct - peripheral nodular densities with wedge shaped infarcts.
Can cavitate.
Feeding vessel sign - nodule with big vessel going towards it (also seen with haematogenous mets).
Empyema and pneumothorax are known complications.
Causes for lung cavities (6)
CAVITY:
Cancer (usually squamous cell)
Autoimmune (Wegeners, Rheumatoid/Caplan syndrome)
Vascular (septic emboli, other emboli)
Infection (TB)
Trauma (Pneumatoceles)
Young (Congenital - CCAMs, Sequestrations)
Lemierre Syndome - definition
Jugular vein thrombosis with septic emboli.
Lemierre syndrome - cause (2)
Seen after oropharyngeal infection or recent ENT surgery.
Causative organism is commonly Fusobacterium Necrophorum.
