Lymph node aspirate from a California wine-country dog.
A 4-year-old, male Golden Retriever was presented to the Veterinary Medical Teaching Hospital at the University of California-Davis with a history of lethargy, inappetance, and vomiting. The patient had generalized lymphadenomegaly, marked thrombocytopenia, mild anemia, and moderate hypoalbuminemia. Moderate to marked histiocytic inflammation and lymphocytic-plasmacytic reactivity of the mesenteric, left popliteal, and right mandibular lymph nodes were diagnosed cytologically. Many macrophages contained granular to amorphous material of a uniform blue color, occasionally in morula formation, suggestive of rickettsial organisms. Exposure to raw trout was subsequently documented, leading to a presumptive diagnosis of salmon poisoning disease (SPD). The patient responded quickly to doxycycline therapy for the causative agent of SPD (Neorickettsia helminthoeca). SPD should be considered as a differential diagnosis for a canine patient with clinical signs of vomiting, diarrhea, lethargy, and lymphadenomegaly; laboratory findings of thrombocytopenia and hypoalbuminemia; and potential exposure to raw fish from an endemic area. The cytologic finding of rickettsial inclusions within lymph node macrophages is reportedly seen within a majority of SPD cases and can be valuable in supporting a clinical suspicion of SPD, as it was in this case.
Johns
Jennifer L
JL
Veterinary Medical Teaching Hospital, School of Veterinary Medicine, University of California - Davis, CA, USA. jljohns@ucdavis.edu
Strasser
Jennifer L
JL
Zinkl
Joseph G
JG
Christopher
Mary M
MM
D000711:Anaplasmataceae Infections / Q000175:diagnosis / Q000188:drug therapy / Q000473:pathology / Q000662:veterinary*; D000818:Animals; D000900:Anti-Bacterial Agents / Q000627:therapeutic use; D044963:Biopsy, Fine-Needle; D002140:California; D004283:Dog Diseases / Q000175:diagnosis* / Q000188:drug therapy / Q000382:microbiology / Q000473:pathology; D004285:Dogs; D004318:Doxycycline / Q000627:therapeutic use; D008198:Lymph Nodes / Q000473:pathology*; D008297:Male; D041102:Neorickettsia / Q000302:isolation & purification*
D000900:Anti-Bacterial Agents; D004318:Doxycycline