Radiology · Year 4 · from Radiology

Case 3: Usual Interstitial Pneumonia (UIP) Pattern

Patient Demographics

  • Age: 71 years
  • Sex: Male

Chief Complaint

Progressive dyspnea on exertion over 2 years

Presenting Symptoms

The patient reports gradually worsening shortness of breath that initially occurred only with strenuous activity but now limits him to walking one block on flat ground. He has a dry, non-productive cough that has persisted for over a year. He denies fevers, weight loss, hemoptysis, or known exposures to asbestos, birds, or organic dusts. He is a former smoker with a 20 pack-year history, quit 15 years ago.

Physical Exam Findings

  • Vital Signs: BP 126/78 mmHg, HR 82 bpm, RR 18/min at rest, SpO2 94% on room air (drops to 86% with ambulation)
  • General: Well-appearing male with mild clubbing of fingernails
  • Pulmonary: Bilateral fine inspiratory crackles ("velcro" crackles) at lung bases, no wheezes
  • Cardiovascular: Regular rate and rhythm, no peripheral edema

Imaging Findings and Interpretation

High-Resolution CT (HRCT) Chest:

  • Distribution: Bilateral, peripheral, and basal predominant fibrotic changes
  • Honeycombing: Subpleural clustered cystic airspaces with thick walls (3-10mm diameter) at both lung bases - pathognomonic for UIP pattern
  • Traction bronchiectasis: Dilated airways within areas of fibrosis
  • Reticulation: Interlobular and intralobular septal thickening
  • Minimal ground-glass opacity: Limited areas of ground glass, consistent with UIP rather than NSIP
  • No features suggesting alternative diagnosis: No upper lobe predominance, air trapping, or centrilobular nodules that would suggest hypersensitivity pneumonitis

Pattern Classification: The combination of basal-peripheral predominant honeycombing, traction bronchiectasis, and reticulation WITHOUT features suggesting alternative diagnosis meets criteria for a DEFINITE UIP pattern on HRCT. Per 2018 ATS/ERS guidelines, this imaging pattern in the appropriate clinical context is diagnostic for idiopathic pulmonary fibrosis without need for surgical lung biopsy.

Diagnosis

Idiopathic Pulmonary Fibrosis (IPF) based on definite UIP pattern on HRCT in appropriate clinical context

Management

  1. Multidisciplinary discussion confirming diagnosis (pulmonology, radiology, pathology)
  2. Pulmonary function tests (expected restrictive pattern with reduced DLCO)
  3. Antifibrotic therapy: Pirfenidone or Nintedanib to slow disease progression
  4. Supplemental oxygen for exertional hypoxemia
  5. Pulmonary rehabilitation program
  6. Lung transplant evaluation given progressive disease (age-appropriate candidate)
  7. Vaccinations: Pneumococcal and annual influenza
  8. Avoid known exacerbation triggers
  9. Palliative care involvement for symptom management and advance care planning

Radiological Image

Image Description: High-resolution CT of the chest demonstrating the usual interstitial pneumonia (UIP) pattern with basal-predominant honeycombing (clustered cystic airspaces with thick walls), traction bronchiectasis, and reticulation. This pattern is diagnostic for idiopathic pulmonary fibrosis.

Source: Wikimedia Commons - "CT scan of idiopathic pulmonary fibrosis" URL: https://commons.wikimedia.org/wiki/File:IPF_amiodarone.JPG License: Creative Commons Attribution-Share Alike 3.0 Unported

Learning Points

  1. Air Bronchograms and the Silhouette Sign: Air bronchograms indicate alveolar consolidation with patent airways, characteristic of pneumonia. The silhouette sign localizes pathology based on which borders are obscured - right hemidiaphragm obscuration indicates right lower lobe involvement.
  1. CT Pulmonary Angiography Protocol: CTPA requires precise bolus timing to maximize pulmonary arterial opacification. Key findings include intraluminal filling defects, the "polo mint sign," and secondary signs of RV strain that influence management decisions.
  1. UIP Pattern Recognition: The combination of honeycombing, traction bronchiectasis, and basal-peripheral predominant fibrosis without features suggesting alternative diagnoses constitutes a definite UIP pattern, which is diagnostic for IPF without biopsy.
  1. Fleischner Society Guidelines: For pulmonary nodule management, size, morphology, and patient risk factors determine follow-up intervals. HRCT patterns guide interstitial lung disease diagnosis through recognition of specific imaging features.

All cases for this lecture as Markdown