Pulmonary opacities on chest x-ray

Overview

There are 3 major patterns of pulmonary opacity:

• Airspace filling
• Interstitial patterns
• Atelectasis

Patterns

1. Airspace filling

• Localized = segmental
• Diffuse or multifocal

2. Interstitial patterns

• Reticular—fine or coarse linear shadows
• Reticulonodular
• Nodular—small (2 to 3 mm), medium, large, or masses (>3 cm)

3. Atelectasis

• Diminished aeration of lung
• Associated with signs of volume loss

Causes of pulmonary opacity

Focal airspace disease

• Pneumonia
• Pulmonary embolism: infarction or intrapulmonary hemorrhage
•  Neoplasm: alveolar cell carcinoma, lymphoma (usually diffuse)
• Atelectasis: opacity accompanied by signs of volume loss

Diffuse or multifocal airspace disease

• Pulmonary edema: CHF and non-cardiogenic pulmonary edema
• Pneumonia: bacterial, viral, Mycoplasma, Pneumocystis
• Hemorrhage: trauma (contusion), immunologic (Goodpasture’s), bleeding diathesis, pulmonary  embolism
• Neoplasm: alveolar cell carcinoma, lymphoma
• Desquamative interstitial pneumonitis (DIP), alveolar proteinosis
• Bat-wing pattern—Central opacification with peripheral clearing—characteristic of pulmonary edema

Fine reticular pattern

Acute:

• Interstitial pulmonary edema
• Interstitial pneumonitis: viral, Mycoplasma
  (Airspace filling often accompanies interstitial pneumonia and pulmonary edema)

Chronic:

• Lymphangitic metastasis, sarcoidosis, eosinophilic granuloma, collagen vascular diseases, inhalation injuries, idiopathic pulmonary fibrosis (“fibrosing alveolitis”), resolving pneumonia

Coarse reticular pattern

• Honeycomb lung—end-stage pulmonary fibrosis
• Also seen when pneumonia or pulmonary edema occurs in patients with underlying emphysema

Reticulnodular pattern

• A common radiographic pattern that encompasses the same disorders as reticular patterns

Miliary pattern — 2 to 3 mm well-defined nodules (“micronodular pattern”)

• Tuberculosis, Fungal, Nocardia, Varicella
• Silicosis, Coal Worker’s lung, Sarcoidosis, Eosinophilic granuloma
• Neoplastic (adenocarcinoma, thyroid)

Nodular pattern — Margins of the lesions are generally well-defined. Mass: >3 cm

• Neoplasm: metastatic, lymphoma; benign tumors
• Fungal or parasitic infection, septic emboli
• Rheumatoid nodules, Granulomatosis With Polyangiitis (Wegener granulomatosis)

CCC Differential Diagnosis Series
NEURO	Anosmia, Ataxia, Blepharospasm, Bulbar and Pseudobulbar palsy, Central Pontine Myelinosis, Cerebellar Disease, Chorea, Cranial nerve lesions, Dementia, Dystonia, Exophthalmos, Eye trauma, Facial twitches, Fixed dilated pupil, Horner syndrome, Loss of vision, Meningism, Movement disorders, Optic disc abnormality, Parkinsonism, Peripheral neuropathy, Radiculopathy, Red eye, Retinal Haemorrhage, Seizures, Sudden severe headache, Tremor, Tunnel vision
RESP	Bronchial breath sounds, Bronchiectasis, High airway pressures, Massive haemoptysis, Sore throat, Tracheal displacement
CVS	Atrial Fibrillation, Bradycardia, Cardiac Failure, Chest Pain, Murmurs, Post-resuscitation syndrome, Pulseless Electrical Activity (PEA), Pulsus Paradoxus, Shock, Supraventricular tachycardia (SVT), Tachycardia, VT and VF, SVC Obstruction
GIT	Abdominal distension, Abdominal mass, Abdominal pain, Asterixis, Dysphagia, Hepatomegaly, Hepatosplenomegaly, Large bowel obstruction, Liver palpation abnormalities, Lower GI haemorrhage, Malabsorption, Medical causes of abdominal pain, Rectal mass, Small bowel obstruction, Upper GI Haemorrhage
GUT	Genital ulcers, Groin lump, Scrotal mass, Urine colour, Urine Odour, Urine transparency,
MSK	Arthritis, Shoulder pain, Wasting of the small muscles of the hand
DERM	Palmar erythema, Serious skin signs in sick patients, Thickened Tethered Skin, Leg ulcers, Skin Tumour, Acanthosis Nigricans
ENDO	Diabetes Insipidus, Diffuse Goitre, Gynaecomastia, Hirsutism, Hypoglycaemia, SIADH, Weight Loss
HAEM	Splenomegaly
PAEDS	Floppy infant
MISC	Anaphylaxis, Autoimmune associated diseases, Clubbing, Parotid Swelling, Splinter haemorrhages, Toxic agents and abnormal vitals, Toxicological causes of cardiac arrest
IMAGING	CHEST: Atelectasis, Hilar adenopathy, Hilar enlargement on CXR, Honeycomb lung, Increased interstitial markings, Mediastinal widening on mobile CXR, Pulmonary fibrosis, Pseudoinfiltrates on CXR, Pulmonary opacities on CXR, ABDO: Gas on abdominal X-ray, Kidney mass, BRAIN: Intracranial calcification, Intracranial structures with contrast, Ventriculomegaly, OTHER: Pseudofracture on X-Ray,
LABS	LOW: Anaemia, Hypocalcaemia, hypochloraemia, Hypomagnesaemia,  HIGH: Bilirubin and Jaundice, Hyperammonaemia, Hypercalcaemia, Hyperchloraemia, Hyperkalaemia, Hypermagnesaemia,  ACID BASE: Acid base disorders, Resp. acidosis, Resp. alkalosis, Creatinine, CRP, Dipstick Urinalysis, Laboratory Urinalysis, Liver function tests (LFTs), Pleural fluid analysis, Urea, Urea Creatinine Ratio, Uric acid, Urinalysis, Urine Electrolytes

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