Possible imaging diagnosis is
Case 300
【Progress】
She was re-given steroid for a while. It induced relief of symptoms.
【Discussion】
Microscopic polyangiitis and granulomatosis with polyangiitis are ANCA-(antineutrophil cytoplasmic antibodies) related diseases. They are caused by neutrophils firmly fixed to vessels. Neutrophils contain granules with protease and reactive oxygen species, inducing damages to vessel wall (1). Meanwhile, acute eosinophilic pneumonia, chronic eosinophilic pneumonia and eosinophilic granulomatosis with polyangiitis are caused by eosinophils fixed to vessels. Eosinophils contain granules with ribonuclease (RNase) and deoxyribonuclease (DNase) (2, 3). In a sense, eosinophils own powerful weapons to the opponent. It is known that eosinophils appear and attack effectively when parasites infection occur, whereas neutrophils attack to parasites is not effective. When eosinophils firmly fixed, it induces possibles damages to vessel wall.
Eosinophils count fewer in number than neutrophils in healthy peripheral blood. The situation called eosinophilia indicates number of eosinophils more than 500/mm3 or more than 10 % of all white cells. Then, it is imperative to check white blood cell numbers including its component rate of neutrophils and eosinophils, also in chest CT interpretation.
What situation makes to check counts of eosinophils in chest CT interpretation?
Acute eosinophilic pneumonia is characteristic of hilar consolidation with pleural effusion on CT, resembling cardiac heart failure (1-6). Chronic eosinophilic pneumonia is characteristic of ground glass opacity or fibrous ground glass in marginal pulmonary area, resembling cryptogenic organizing pneumonia, microscopic polyangiitis (ANCA related disease) (2-6) and viral infection such as COVID-19. Eosinophilic granulomatosis with polyangiitis is characteristic of marginal ground glass adjacent with multiple nodules.
In our case, CT showed ground glass opacity in bilateral apical regions not like bacterial infection but like smoking related disease. Laboratory test revealed eosinophils of 27.7%. CT six months before showed relatively large ground glass opacity in left lobe and small ground opacity in right lobe that does not meet acute eosinophilic pneumonia, chronic eosinophilic pneumonia and eosinophilic granulomatosis with polyangiitis. However, it is not contradictory with Loffler syndrome (simple pulmonary eosinophilia) that occurs from parasite infection, drug-induced pneumonia and unknown origin (7).
【Summary】
We presented a 23-year-old female presented in our hospital with high fever and general fatigue. Laboratory test revealed eosinophilia, 27.7%. Chest CT showed bilateral ground glass opacity in bilateral apical regions. She was diagnosed eosinophilic pneumonia in a respiratory specialist hospital. Chest CT six months before showed ground glass opacity mainly extensive in left lobe that did not meet either acute eosinophilic pneumonia, chronic eosinophilic pneumonia, or eosinophilic granulomatosis with polyangiitis but Loffler syndrome (simple pulmonary eosinophilia). It is borne in mind that there four types of pulmonary eosinophilia; simple pulmonary eosinophilia like our case, acute eosinophilic pneumonia whose CT image is like acute cardiac failure with hilar consolidation associated with pleural effusion; chronic eosinophilic pneumonia whose CT image is marginal ground glass or fibrous gland glass: eosinophilic granulomatosis with polyangiitis whose CT image is multiple nodules adjacent with marginal ground glass or fibrous gland glass. Further, there are two types of ANCA diseases that indicates neutrophils firmly fixed to vessels causing vessel wall damages; microscopic polyangiitis whose CT images are characteristic of marginal fibrous ground glass opacity resembling COP and chronic eosinophilic pneumonia: granulomatosis with polyangiitis whose CT images are multiple nodules often associated with cavity formation.
【References】
1.Ananthakrishnan L, et al. Wegener's granulomatosis in the chest: high-resolution CT findings. AJR Am J Roentgenol. 2009;192 (3): 676-82.
2.Jeong YJ, et al. Eosinophilic lung diseases: a clinical, radiologic, and pathologic overview. Radiographics. 27 (3): 617-37.
3.Johkoh T, et al. Eosinophilic lung diseases: diagnostic accuracy of thin-section CT in 111 patients. Radiology. 2000;216 (3): 773-80
4.Janz D, et al. Acute Eosinophilic Pneumonia: A Case Report and Review of the Literature. Crit Care Med. 2009;37(4):1470-4. doi:10.1097/CCM.0b013e31819cc502 - Pubmed
5.Nishio M, et al. Idiopathic acute eosinophilic pneumonia. Intern. Med. 1992;31 (9): 1139-43. Intern. Med. (link) - Pubmed citation
6.King MA, et al. Acute eosinophilic pneumonia: radiologic and clinical features. Radiology. 1997;203 (3): 715-9
7.Allen JN. Drug-induced eosinophilic lung disease. Clin Chest Med 2004; 25:77–88
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