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ULAM IN-VIVO ANIMAL CORE
UNIVERSITY OF MICHIGAN
Main Laboratory
North Campus Research Complex
2800 Plymouth Rd., Bld. 36: G155/157
Ann Arbor, MI 48109-2800
(734) 647-0731
Satellite Location
3527 Animal Research Facility
1150 W. Medical Center Dr.
Ann Arbor, MI 48109-0614
(734) 936-3803
ulam-ivac@umich.edu

Case Information:

Necropsy Date: 12/9/23 Clinician: Lester
IVAC Service ID: 23-3219 Prosector: Boulanger
Species: SUS Gross necropsy pathologist: Curtis
Principal Investigator: Xu Other contact: arieck
Depart:

Animal ID:

Animal ID: Clinical Number: Age: Sex: Genotype/Strain/Study: Mode of Death:
Ben Curtis
15-14 23x10872 ~30 kg M SUS Euthanized-Injectable

Clinical History:

Presented 12/9 for concerns of respiratory distress with previous history of general anesthesia involving craniotomy and intubation. Euthanized given decline in respiratory status.

Final Diagnos(es) for Case

Organ/System Process Diagnosis
Respiratory Trauma Laryngeal trauma with perforation and subsequent pneumomediastinum/retroperitoneum
Respiratory Inflammatory Necrotizing and suppurative laryngitis with intralesional bacteria

Final Comments:

Gross and histological findings are consistent with trauma to the larynx at the level of the median ventral and lateral ventricles, just caudal to the vocal folds. These blind ended pouches, along with sharp angle of deflection from the pharynx through the larynx to the trachea, and the naturally narrow diameter of the larynx can commonly make intubation in pigs difficult. No other significant lesions were noted histologically. Bacterial culture grew common commensal organisms, but not primary pathogens.

Pathologist Only:

Case Complete? Yes
Final Review Pathologist: Benjamin Curtis, DVM, DACVP
Completion Date: 2023-12-19

Gross Findings

Animal 1 15-14
Body condition score: 3/5 3/5
Carcass condition: Intact Intact
Autolysis: None None

Gross Lesions

Organ System Evaluated? (Y/N/Some animals) Findings or Comments Y/N Comments (only if Findings)
Cardiovascular Y Y Marked diffuse mediastinal emphysema which extends caudally through the diaphragm to the retroperitoneal space. A small pericardial abscess adhered to cardiac apex (swabbed).
Endocrine Y N
Gastrointestinal Y N food noted in stomach
Hematolymphoid Y N
Hepatic Y N
Integument Y Y Focal erosion at plenum of nose. Craniotomy surgery site is intact, clean, and free of exudate. Deep to the incision is a large hematoma.
Musculoskeletal Y N
Nervous Y N The meninges deep to the hematoma are intact, clean, and free of exudate. The brain tissue is unremarkable.
Reproductive Y N
Respiratory Y Y Lungs float in formalin, blood clots noted in large airways with caudal lobe edema. Trachea adjacent to larynx demonstrated multifocal to coalescing dark-green discoloration with fibrinonecrotic membrane. Thyroid membrane/ligament of larynx thinned but intact with potential compromise. Just caudal to the vocal folds, at the edges of the ventral median and lateral ventricles are markedly hemorrhagic, hyperemic, and lined by necrotic debris (swabbed - submitted). The injury tracks deeper ventrally into the surrounding soft tissues and opens into a pocket of purulent exudate (swabbed). Tissues around the larynx are emphysematous. The mucosal surface of the trachea distally is smooth, shiny, and clean.
Urinary Y Y Retroperitoneal emphysema is most easily observed by the left kidney.

Additional Procedures Performed: Check all that apply

Tissues Frozen lung, liver, kidney, spleen, GI (cecum, small intestine, large intestine)
Tissues Refrigerated Culture swabs from the ventral tracheal abscess and pericardial abscess were saved.
Other The swab from the larynx, injury site, was sent for general bacteria culture

Microscopic Findings

Organ/Slide Findings Y/N Description
Heart N
Kidneys N
Larynx Y Regionally extensive mucosal ulceration, necrosis with marked suppurative inflammation and colonizing bacterial colonies.
Liver N
Lungs Y Mild to moderate expansion of the alveolar septae. Alveolar spaces are generally unremarkable.
Spleen N

Microscopic Morphologic Diagnos(es)

Organ/System Process Morphologic Diagnosis
Larynx Trauma Tracheitis, laryngitis, with fibrinonecrotic membrane, marked, acute