JPC SYSTEMIC PATHOLOGY

RESPIRATORY SYSTEM

August 2017

P-B01

 

Signalment (JPC # 2317878):  Laboratory rat

HISTORY:  Unknown history

HISTOPATHOLOGIC DESCRIPTION:  Lungs:  Affecting approximately 90% of one section of lung and 10% of the other, there are multifocal to coalescing nodules of inflammation that surround bronchi, bronchioles, and associated blood vessels, effacing the underlying connective tissue and distorting and compressing the adjacent alveolar architecture.  This inflammatory infiltrate is composed of numerous macrophages, with lymphocytes, plasma cells, and fewer neutrophils, admixed with scattered fibrin, hemorrhage, and edema.  Inflammatory cells multifocally infiltrate the respiratory epithelial lining (which is frequently hyperplastic with piling up of cells that form folds within the airway lumen) into the adjacent connective tissue, alveolar septa and avleoli.  Multifocally, bronchi and bronchioles are expanded (up to 4mm) by a neutrophilic exudate (bronchiectasis and bronchiolectasis).  Cilia and epithelial cells are often lost.  Bronchiolar associated lymphoid tissue (BALT) is markedly hyperplastic with a pale germinal center and tingible-body macrophages.  Adjacent, less affected alveolar septa are compressed, collapsing alveolar lumina and there are multiple foci of alveolar emphysema. 

Esophagus: No significant findings.

MORPHOLOGIC DIAGNOSIS:  Lung:  Bronchopneumonia, suppurative, subacute, diffuse, severe, with bronchiectasis, bronchiolectasis and bronchiolar-associated lymphoid hyperplasia, rat, rodent.

ETIOLOGIC DIAGNOSIS:  Mycoplasmal pneumonia

CAUSE:  Mycoplasma pulmonis

CONDITION:  Murine respiratory mycoplasmosis (MRM)

GENERAL DISCUSSION:

PATHOGENESIS:

TYPICAL CLINICAL FINDINGS:

TYPICAL GROSS FINDINGS:

TYPICAL LIGHT MICROSCOPIC FINDINGS:

ULTRASTRUCTURAL FINDINGS:

ADDITIONAL DIAGNOSTIC TESTS:

DIFFERENTIAL DIAGNOSIS:

COMPARATIVE PATHOLOGY:

REFERENCES:

  1. Barthold SW, Griffey SM, Percy DH, eds. Pathology of Laboratory Rodents and Rabbits. 4th ed. Ames, IA: Wiley-Blackwell; 2016:63-65, 134-136, 186, 228.
  2. Boulianne M, ed. Avian Disease Manual. 7th ed. Jacksonville, FL: American Association of Avian Pathologists, Inc; 2013:106-116.
  3. Caswell JL, Williams KJ. Respiratory system. In: Maxie MG, ed. Jubb, Kennedy and Palmer’s Pathology of Domestic Animals. Vol 2. 6th ed. St. Louis, MO: Elsevier; 2016: 533-535, 551-554, 563-564, 579, 590.
  4. Cheville NF. Ultrastructural Pathology: The Comparative Cellular Basis of Disease. 2nd ed. Ames, Iowa: Blackwell Publishing; 2009: 442-444.
  5. Desjardins DR, Kennedy LH, Agnew DW. Pathology in practice. Mycoplasma pulmonis J Am Vet Med Assoc. 2012; 240(2):155-157.
  6. Dixon D, Herbert R, Sills R, Boorman G. Lungs, pleura, and mediastinum. In: Pathology of the Vienna, IL: Cache River Press; 1999:300-302.
  7. Noga, EJ. Fish Disease: Diagnosis and Treatment. 2nd ed. Ames, IA: Wiley-Blackwell; 2010: 176.
  8. Priestnall SL, Mitchell JA, Walker CA, Erles K, Brownlie J. New and emerging pathogens in canine infectious respiratory disease. Vet Pathol. 2014; 51(2):492-504
  9. Rothenburger JL, Himsworth CG, Clifford CB, Ellis J, Treuting PM, Leighton FA. Respiratory pathology and pathogens in wild urban rats (Rattus norvegicus and Rattus rattus). Vet Pathol. 2015; 52(6): 1210-1219.


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