Diagnosis of Nonregenerative Immune Mediated Hemolytic Anemia in a Cat

Diagnosis of Nonregenerative Immune Mediated Hemolytic Anemia in a Cat

Gaspar is a 4 year old neutered male cat presented to Veterinarium Clinic. According to the owner, the patient had exhibited anorexia, lethargy, vomiting, and weight loss over the preceding week. Notably, Gaspar had no prior history of medical problems.

On physical examination, the patient was tachycardic and tachypneic, with hypotension and pale mucous membranes. Gaspar was dehydrated, lethargic, and demonstrated reduced responsiveness to external stimuli. Based on the clinical findings, anemia was suspected by Nutsa Besashvili, the clinic’s internist and ultrasonographer.

A complete blood count performed in the clinic’s laboratory confirmed decreased erythrocyte count and hemoglobin concentration. Thrombocytopenia and leukopenia were also identified.

The anemia was classified as critical. The hematocrit was reduced approximately 3.5 fold relative to the lower reference limit. Additionally, the anemia was determined to be nonregenerative, indicating insufficient production of new blood cells by the bone marrow. Given the severity of the condition, blood transfusion was considered essential.

Although the clinic does not operate a dedicated overnight inpatient unit, Gaspar remained hospitalized overnight by team decision. The patient received intravenous fluid therapy, symptomatic treatment, and continuous monitoring of vital parameters.

Concurrently, a donor search was initiated. Gaspar required a large volume transfusion, and collection of such a volume from a feline donor would have posed significant risk. Therefore, xenotransfusion was considered the only viable option. In this case, the donor was a 6 year old Hungarian Pointer.

Prior to transfusion, the Hungarian Pointer was confirmed to meet donor eligibility criteria. A donor recipient compatibility test was performed, yielding a positive result.

The transfusion was administered over 4 hours. Immediately following the procedure, Gaspar showed noticeable clinical improvement, becoming more active, resuming grooming behavior, and initiating food intake.

Due to immunologic mechanisms, canine erythrocytes typically undergo destruction in the feline recipient within approximately 2 to 6 days. Consequently, the observed improvement was expected to be temporary. Without adequate endogenous blood cell production, clinical deterioration would have been anticipated.
Therefore, identification and management of the underlying cause of pancytopenia was critical.

Based on hematologic and biochemical analyses, potential causes of anemia including hemorrhage, chronic kidney disease, toxin exposure, and infectious disease were excluded.

By Nutsa Besashvili’s clinical decision, additional PCR testing for FIV and FeLV was performed, as these viruses can impair normal bone marrow function through distinct pathogenic mechanisms.

Gaspar was diagnosed with NRIMHA (Feline Nonregenerative Immune Mediated Hemolytic Anemia). This condition involves immune mediated destruction of circulating erythrocytes as well as immune mediated damage to bone marrow precursor cells. As a result, existing red blood cells are destroyed while effective regeneration is impaired. Due to bone marrow suppression, NRIMHA is frequently associated with thrombocytopenia and leukopenia.

Treatment was initiated with immunosuppressive therapy. Periodic laboratory monitoring demonstrated afavorable response, with hematologic parameters returning to reference ranges. Gaspar continues prescribed medications at home.