CHEST DDx Flashcards
Intra parenchymal Cystic lung Disease:
Associated GGO:
- PJP infection in setting of AIDs: bilateral thin walled upper zone cysts. Gallium +ve.
- DIP: smoker
Associated Nodules:
- LIP: CT disorder (SKE, Sjogrens, RA) or HIV.
- Amyloid: Sjogrens or MM
- LCH: young smoker, bizarre cysts, spares costophrenic angles.
Multifocal / Diffuse:
- LAM (tuberous sclerosis)
- LCH
- Lymphoid Interstitial Pneumonia: CT disorder
- Birt Hogg Dube: lower lobes subpleural, bilateral renal chromophobe RCC, oncocytomas, and facial fibrofolliculomatosis.
- Infection: atypical bacteria, staph, coccidiomycosis.
- Adenocarcinoma.
LCH: bizarre shaped, thick walled
LAM: round shaped, thin walled
Birt Hogg Dube: oval shaped, thin walled.
Nodular Lung Disease:
Sub pleural nodules: Diffuse - Random pattern:
- Miliary Infection: TB, Mycobacterium, Histioplasmosis.
- Haematogenous Mets.
Sub Pleural Nodules: patchy, subpleural, peribronchovascular, interlobular septa - Perilymphatic pattern:
- Sarcoidosis: upper zone, symmetric, peribronchovascular, hilar nodes.
- Lymphangetic Carcinomatosis: smooth / nodular septal thickening.
- Silicosis / coal workers pneumoconiosis: upper zone posterior, symmetrical.
No subpleural nodules, with Tree and Bud Opacity:
- Infection: acute, typical and atypical, if cavitary - TB.
- Aspiration
- Infectious bronchiolitis: air trapping
- CF bronchiectasis
- ABPA setting of asthma, finger in glove.
No subpleural nodules, with no tree and bud opacity:
- Infection: acute, GGO
- aspiration: acute, dependent
- Oedema: acute, GGO
- Haemorrhage: acute, GGO.
- Hypersensitivity Pneumonitis: GGO, mid/upper zone, but can be diffuse in CC plane wi inflammatory HP, mosaic attenuation, sparing costophrenic angles.
- Respiratory Bronchiolitis ILD: chronic, smoker, uuper zones, GGO.
- Follicular Bronchiolitis: RA or Sjogrens, or immunosuppressed.
- Invasive Mucinous Adenocarcinoma: Chronic, soft tissue with consolidation and lucent bubbly appearance, multi lobar.
- LCH: soft tissue nodules with cysts / cavitations, young smoker, upper zones, sparing costophrenic angles.
Acute GGO:
Infection - usually atypical Oedema - usually dependent Acute lung injury / ARDS Haemorrhage Aspiration Acute hypersensitivity pneumonitis Acute eosinophilic pneumonia
Chronic GGO:
Hyper sensitivity pneumonitis NSIP DIP / RB LIP / Follicular bronchiolitis Invasive mucinous adenocarcinoma Organising pneumonia Eosinophilic pneumonia Sarcoidosis Lipoid pnuemonia Alveolar proteinosis
Peripheral distribution GGO:
NSIP DIP OP Eosinophilic pneumonia Atypical or viral pneumonia Oedema - usually non cardiogenic.
Patchy geographic GGO with central predominance:
Hypersensitivity pneumonitis RB LIP Follicular bronchiolitis OP Sarcoidosis Alveolar proteinosis
Unilateral / highly asymmetric distribution of GGO:
Invasive pulmonary mucinous adenocarcinoma
Lipoid pneumonia
GGO with mosaic perfusion / air trapping:
Hypersensitivity pneumonitis
Crazy paving
ACUTE:
- oedema
- atypical infections
- diffuse alveolar damage / ARDS
- Haemorrhage
- Acute hypersensitivity pneumonitis
- Acute eosinophilic pneumonia.
CHRONIC:
- Alveolar proteinosis (Favoured Dx)
- Hyper sensitivity pneumonitis
- NSIP
- DIP / RB
- LIP / Follicular bronchiolitis
- Invasive mucinous adenocarcinoma
- Organising pneumonia
- Eosinophilic pneumonia
- Sarcoidosis
- Lipoid pnuemonia
GGO with centrilobular nodules:
Hypersensitivity pneumonitis
RB
Follicular bronchiolitis
Invasive mucinous adenocarcinoma
GGO with signs of fibrosis (honey combing, traction bronchiectasis, irregular reticulation)
NSIP
Hypersensitivity Pneumonitis
Indeterminate UIP.
Peripheral distribution chronic consolidation:
Chronic eosinophilic pneumonia
Organising pneumonia (Polymyositis / dermatomyositis)
COVID
PEs
Causes of organising Pneumonia:
Cryptogenic organising pneumonia Drugs CT disease Toxic Inhalation Immunodeficiencies Graft vs Host.
DDx for organising pneumonia / Atoll sign:
Chronic eosinophilic pneumonia
Hypersensitivity pneumonitis: centrilobular nodules.
Infections - fungal: neutropenia.
Granulomatosis polyangiitis.
Pulmonary infarction: peripheral wedge shaped
Head Cheese Sign:
Hypersensitivity - most likely!
Respiratory bronchiolitis / desquamative interstitial pneumonia
Follicular bronchiolitis / lymphoid interstitial pneumonia
Atypical infections
Sarcoid
2 seperate processes: oedema and asthma.
Upper lobe predominant fibrosis: “ STROLA”C
Sarcoidosis TB Radiation Occupation: pneumoconioses LCH Ankylosing spondylitis Chronic HP
Lower lobe predominant fibrosis:
UIP / Idiopathic pulmonary fibrosis Connective tissue disease Drug fibrosis Asbestosis Hypersensitivity pneumonitis (mid zones, can be diffuse) Chronic aspiration.
Reticulonodular pattern: “VOTE SSSX”
ACUTE:
- Viral (lymphadenopathy)
- Oedema (effusion)
- TB (middle to upper lobe predominance, lymphadenopathy)
- Eosinophilic pneumonia / HP
CHRONIC:
- Sarcoidosis (middle to upper lobe, lymphadenopathy)
- Silicosis (middle to upper lobe, lymphadenopathy)
- Secondaries (carcinomatosis, effusion, lymphadenopathy)
- Langerhans Histiocystosis X (normal to increased lung volumes, middle to upper lobe).
- Asbestosis: pleural thickening / calcification.
- LAM: associated pneumothorax.
Mid to upper zone bronchiectasis:
CF
ABPA
TB
Lower zone bronchiectasis:
Chronic infection
Aspiration
Immunodeficiency
Primary ciliary dyskinesia
Tree in Bud opacities:
Bacterial infection
mycobacterial infection
Fungal ingection
Viral infection
Cystic fibrosis
ABPA
Primary ciliary dyskineasia
Immunodeficiency
Diffuse panbrochiolitis
Follicular bronchiolitis
Invasive mucinous adenocarcinoma
Aspiration
CT findings of parenchymal lung disease as cause of pulmonary HTN
Fibrosis, emphysema, or cystic lung disease
CT findings of chronic pulmonary thromboembolism as cause of pulmonary HTN:
Pulmonary artery filling defects or occlusion, mosaic perfusion.
CT findings of idiopathic pulmonary HTN:
Dilated main pulmonary artery, centrilobular nodules of GGO
CT findings of pulmonary veino-occlusive disease as cause of pulmonary HTN:
Smooth interlobular septal thickening, dilated main pulmonary artery, normal sized pulmonary veins
CT findings of pulmonary capillary haemangiomatosis as cause of pulmonary HTN:
Centrilobular nodules of ground glass opacity, progression of findings after treatment with vasodilators.
CT findings of IV injection of oral medications as cause of pulmonary HTN:
Diffuse small homogenous branching centrilobular nodules.
CT findings of sickle cell disease as cause of pulmonary HTN:
Dense bones, rugger jersey spine
CT findings of liver disease as cause of pulmonary HTN:
Small nodular liver
CT findings of left sided heart disease as cause of pulmonary HTN:
Left atrial or ventricular dilation, smooth interlobular septal thickening.
Asymmetric / focal pulmonary oedema:
Patient position Asymmetric emphysema / bulls disease. Mitral regurgitation. Pulmonary embolism / vascular obstruction Neurogenic pulmonary oedema
UIP Terminology:
Typical UIP pattern:
- Reticulation
- Honeycombing
- Sub pleural / basilar distribution
- Absence of atypical features.
Probable UIP pattern:
- Reticulation
- No honey combing
- Sub pleural / basilar distribution
- Absence of atypical features.
CT pattern indeterminate for UP:
- Findings of fibrosis
- Variable or diffuse distribution
- Inconspicuous features suggestive of non-UIP pattern.
CT features most consistent with non-IPF diagnosis:
- Peribronchovascular distribution
- Mid - upper distribution
- Atypical features: mosaic perfusion, air trapping, ground glass opacity, consolidation, nodules, cysts.
- Etiologies of non IPF fibrotic disease: NSIP, Hypersensitivity pneumonitis, sarcoid, silicosis, coal workers pneumoconioses.
Etiologies of UIP:
Idiopathic pulmonary fibrosis
Connective tissue disease
Drug toxicity
Asbestosis
CT findings of NSIP:
Sub pleural, basilar predominant pattern GGO, irregular reticulation, traction bronchiectasis No / minimal honey combing Immediate sub pleural sparing.
Etiologies of NSIP:
- Idiopathic NSIP
- Connective tissue disease - check oesphagus ? scleroderma.
- Drug toxicity
- Hypersensitivity Pneumonitis
CT Findings of Desquamative Interstitial Pneumonia:
Subpleural basilar predominant GGO Cysts or emphysema Fibrosis may develop over time May see centrilobular nodules of GGO with a mid to upper zone predominance and mosaic perfusion, implying background of RB.
DDx for symmetrical mediastinal hilar lymphadenopathy:
Sarcoid
Pneumoconioses
Amyloidosis
Castleman’s disease
Mets - usually asymmetric, can be seen in mets from GI / GU / Lung / breast cancers and leukaemia.
Lymphoma - usually asymmetric.
Mycobacterial / fungal infection - usually asymmetric.
DDx for patchy consolidation:
Sarcoid Organising pneumonia Chronic eosinophilic pneumonia Invasive mucinous adenocarcinoma Lymphoma Lipoid pneumonia
Head cheese sign:
Hypersensitivity pneumonitis
Desquamative interstitial pneumonia / respiratory bronchiolitis.
Follicular bronchiolitis / lymphoid interstitial pneumonia
Sarcoidosis
Atypical infections.
Causes of pulmonary Haemorrhage:
Pulmonary Renal Syndromes:
- ANCA +ve vasculitis
- granulomatosis with polyangiitis
- Microscopic polyangiitis
- Anti GBM
- Auto immune connective tissue disease
- SLE
- Polymyositis
- Scleroderma
- HSP
- Drug induced vasculitis
- idiopathic pulmonary renal syndrome
Without renal disease:
- Anticoagulation
- Pulmonary embolism
- Idiopathic pulmonary haemosiderosis
- Trauma
- Bone marrow transplantation.
Chronic Alveolar Lung Disease:
"SALA" Sarcoidosis Alveolar proteinosis Lymphoma / lipoid pneumonia. Adenocarcinoma in Situ