Figures
- Figure 1
a, b) Non-contrast chest CT 8 months prior to presentation, when the patient was mildly symptomatic, in the coronal and axial planes, respectively. These show mild basilar-predominant peripheral reticulations (dashed white arrows) and minimal GGOs (solid white arrows). c, d) Representative coronal and axial images during acute exacerbation, the solid white arrows indicate GGOs. e, f) Representative coronal and axial images after discontinuation of nitrofurantoin and initiation of steroid therapy, with near-complete resolution of GGOs and peripheral reticulations.
- Figure 2
Representative a) coronal and b) axial images from a non-contrast chest CT of the abdomen and pelvis of this 64-year-old female obtained to evaluate for renal calculus. An obstructive calculus is seen in the distal right ureter (solid white arrow) with proximal hydroureteronephrosis (dotted white arrow).
Tables
- Table 1
Pulmonary function tests before and after discontinuation of nitrofurantoin
FVC FEV1 DLCO mL·min−1·mmHg−1 Tiffeneau Index Initial encounter 1.78 L (56%) 1.83 L (62%) 10.14 (49%) 87% 6-week follow-up 2.25 L (71%) 1.7 L (69%) 13.4 (65%) 76% - Table 2
Drug-induced pneumonitis clinical and radiographic features
Aetiology Many drugs, most commonly chemotherapy agents (bleomycin, busulfan, cyclophosphamide, methotrexate, thalidomide), immunosuppressive agents (sirolimus), amiodarone, antibiotics (nitrofurantoin, amphotericin B), pembrolizumab Incidence Overall incidence unknown (varies depending on agent) Sex ratio Unknown Age predilection Varies depending on agent (e.g. bleomycin-induced lung injury risk is increased in the elderly)
Median age for acute and chronic nitrofurantoin-induced pulmonary reactions was 59 and 68 years, respectivelyRisk factors Varies depending on agent (e.g. marked increased risk of bleomycin lung injury if cumulative dose exceeds 450 units) Treatment Cessation of offending agent
Corticosteroid therapy is often used, although evidence is lackingPrognosis Varies widely, from complete clinical recovery and resolution of imaging findings to respiratory failure and death Findings on imaging CT findings vary among different aetiologies, includes multifocal GGOs with intralobular interstitial thickening, patchy GGO, centrilobular nodules - Table 3
Differential diagnosis for presenting symptoms of this patient
Differential diagnosis Radiographic findings CT findings Hypersensitivity pneumonitis Low sensitivity, with many patients having normal radiographs
Findings may include: nodular opacities, GGOs or consolidation, fine reticulation, eventual fibrosis with honeycombingMid and upper lobe predominance, centrilobular nodules, bilateral and symmetric airspace opacities (ground glass or consolidation), air trapping with mosaic pattern, head cheese sign, fibrosis with honeycombing Pulmonary interstitial oedema Peribronchial cuffing, septal (Kerley B) lines, interlobular fissure thickening GGOs, interlobular septal thickening, bronchovascular bundle thickening Sarcoidosis Mid and upper lobe predominant opacities, lymphadenopathy, calcified lymph nodes Mid and upper lobe predominant reticulation, honeycombing, traction bronchiectasis, lymphadenopathy, calcified lymph nodes Coronavirus disease 2019 (COVID-19) Bilateral lower lobe predominant airspace opacities Bilateral lower lobe predominant ground glass and consolidative opacities Mycoplasma pneumoniae Unilateral or bilateral patchy consolidation, nodular or reticular opacities Patchy or ground-glass opacities, centrilobular nodules, tree-in-bud, bronchial wall thickening
