3. History
• Ataxic and inappetant
• Been on metacam for 1 week without improvement
• No weight loss
• Drinking normal
• No vomiting
• Biochemistry
– Albumin slightly low
– Total protein > 120g/l
– Decreased WBC
4. Further tests
• FIP profile
– For FIP diagnosis in sick cats
– FCoV antibodies
– Haematology/cytology
– A:G ratio
– Alpha 1 AGP
5. Results
• Haematology smear report
– Platelet numbers adequate but less than reference
– Blood picture poorly regenerative
– Rouleaux formation strongly increased
– Slide agglutination negative
– No evidence of haemoparasites
– Neutrophils show mild toxic change
– Occasional large lymphoblasts
16. References
• Jane M. Dobson, B. Duncan, X. Lascelles (2011). BSAVA Manual of Canine and
Feline Oncology. 3rd ed. Gloucester: British Small Animal Veterinary Association
• Elizabeth Villiers, Laura Blackwood (2005). BSAVA Manual of Canine and Feline
Clinical Pathology. 2nd ed. Gloucester: British Small Animal Veterinary Association
• Ian Ramsey, Bryn Tennant (2001). BSAVA Manual of Canine and Feline Infectious
Diseases. 1st ed. Gloucester: British Small Animal Veterinary Association
• http://www.mayomedicallaboratories.com/media/articles/communique/mar2002.
pdf
• Companion Animal Studies (CAS) lecture – Oncology 3: Approach to lymphoma
and leukaemia. J.S. Morris, BSc, BVSc, PhD, FRCVS
• Companion Animal Studies (CAS) lecture – Feline Infectious Diseases:
Panleucopenia, Cat Flu and FIP. Ian Ramsey, BVSc Phd DSAM FHEA MRVCS
DipECVIM-CA
Notas del editor
Today I will be walking us through how to work through a fairly common presentation you would likely to see in practice. I feel that we can always look up the treatment options and what further diagnostics can be performed but there is no book to help you work through a case.
SIGNALMENT
The patient is 10 year old female neutered domestic short hair that presented on 25th February 2011. The cat lives in a single cat household and is kept as an indoor cat.
HISTORY
The patient has been ataxic and inappetant and has been on metacam for 1 week without improvement. There has been no weight loss. The cat is drinking normally and there have been no signs of vomiting. A biochemistry has been done, of which white blood cells were low, albumin slightly low and total protein was greater than 120g/l. No other abnormalities were found.
FURTHER TESTS
Based on the history and previous biochemistry results, FIP was suspected. Thus, a FIP profile (for FIP diagnosis in sick cats) was requested. The FIP profile consists of the following:
FCoV antibodies serology
Haematology/cytology
Albumin : globulin ratio
Alpha-1 acid glycoprotein
HAEMATOLOGY RESULTS
Platelet numbers adequate but less than reference
Blood picture poorly regenerative
Rouleaux formation strongly increased
Slide agglutination done to rule out autoimmune disease
Slide agglutination negative
No evidence of haemoparasites
The lack of haemoparasites was noted as hyperglobulinaemia (shown in the next slide) can be seen in babesiosis, leishmaniasis and ehrlichiosis (uncommon in cats).
Neutrophils show mild toxic change
Occasional large lymphoblasts
RESULTS
These are the lab results and I have highlighted the abnormalities in the next slide.
ABNORMALITIES
There were some abnormalities in the results and these abnormalities suggest this cat could have FIP.
WBC < 10 x 109
Lymphopenia
total protein (>35g/l consistent with FCoV infection)
globulin
A:G ratio <0.4 (FIP likely)
BUT
However, the lab results for FCoV antibodies and alpha-1 AGP did not support FIP.
FCoV serology
High antibody titre (>640)
Suggestive of FIP
Must be accompanied with clinical signs of FIP
Moderate tire (<320)
Non diagnostic
Consider biopsy of lesions
But most cases of dry FIP have moderate titres
Negative titre
Unlikely to have FIP
Alpha-1 AGP
Values of more than 1500µg/ml correspond with FIP. As this patient only has a alpha-1 AGP level of 280µg/ml, the results are not supportive of FIP.
DIFFERENTIALS
Thus I had to explore differentials. My main differentials were neoplasia and FIV, of which I felt neoplasia was more likely.
The differential of neoplasia was drawn from the elevated globulin levels in the lab results. There are two causes of elevated globulin levels – inflammation and neoplasia. To differentiate between the two causes, a serum protein electrophoresis (SPEP) was done.
SERUM PROTEIN ELECTROPHORESIS (SPEP)
Serum protein electrophoresis (SPEP) measures the protein levels in the blood and classifies it into the different types of proteins – albumin, alpha-1 globulin, alpha-2 globulin, beta globulin and gamma globulin. This will result in either a polyclonal or monoclonal gammopathy.
Polyclonal gammopathy (non neoplastic)
Albumin is the main protein, with mixed levels of other globulins. Polyclonal gammopathy is seen with inflammation or immune mediated disease and FIP.
Monoclonal gammopathy
Gamma globulin is the main protein. Monoclonal gammopathy is seen with various neoplasias such as lymphoma, multiple myeloma and chronic lymphocytic leukaemia. These neoplasias result in a paraneoplastic syndrome called hyperviscosity syndrome. This will be further explained later.
Differentiating between polyclonal and monoclonal
If the base of the globulin spike is similar to that of the albumin spike, it is a monoclonal gammopathy.
SPEP RESULTS
In this case, the SPEP shows a narrow globulin spike and the base of this globulin spike similar to that of the albumin spike. Thus this is a monoclonal gammopathy.
As mentioned earlier, the various neoplasias that demonstrate a monoclonal gammopathy result in hyperviscosity syndrome. Hyperviscosity syndrome occurs when there is an increase in protein in the blood, making the blood more viscous and hence increasing resistance to blood flow. This results in decrease organ perfusion. The brain is thus affected and receives less oxygen, hence is unable to send the appropriate signals to various muscles, ultimately resulting in the ataxia.
NEOPLASIA DIFFERENTIALS
Our first differential is neoplasia – lymphoma, multiple myeloma and chronic lymphocytic leukaemia.
RULING OUT NEOPLASIA DIFFERENTIALS
First and foremost, chronic lymphocytic leukaemia can be ruled out. With chronic lymphocytic leukaemia, there should be a marked increase in mature lymphocytes in circulation (meaning a marked lymphocytosis). However, the lab results show a lymphopenia instead. As the lymphocytosis is very characteristic of CLL, this rules it out as a differential.
Multiple myeloma is rare in both cats and dogs. Anorexia and weight loss are common clinical signs in cats. One third of cats present leucopenic (this patient is mildly leucopenic). Thus this is a possible diagnosis.
There are multiple forms of lymphoma in the cat, with the most common being alimentary lymphoma. Other forms (in order of frequency) include multicentric, mediastinal, nasal, renal and spinal or central nervous system. As further tests have not been performed, we are unable to this time to determine the specific form of neoplasia the patient is suspected to have.
FURTHER TESTS
Unfortunately we never saw the cat again so we are unsure of the outcome and what neoplasia the cat had. But nonetheless, if this was our patient in practice, these are some further tests that could be done.
LYMPHOMA
Abdominal ultrasound – alimentary, renal
Lymph node excision – multicentric
Thoracic radiographs – mediastinal
FNA of mediastinal mass if present – mediastinal
Nasal CT – nasal
Spinal radiography / CT / MRI – spinal or CNS
MULTIPLE MYELOMA
Radiographs – looking for polyostotic osteolytic lesions on appendicular and axial skeleton
Depending on results, could do bone biopsy or bone scintigraphy to further confirm but lesions are characteristic
FELINE IMMUNODEFICIENCY VIRUS (FIV)
I would like to just touch briefly on FIV to explain why I had this on my list of differentials, just to show my thought process when coming up
differentials. I did not think this was very likely and neither did the vets on this case as no FIV test was ordered. Also, this differential was not explored further as the SPEP results were highly suggestive of a neoplastic condition.
The patient is 10 years old, which corresponds with the typical age cats present with FIV. The patient has been reported to be ataxic – neurological signs are often seen with FIV patients as the virus replicates in the brain. Biochemistry results display a lymphopenia, suggesting a possible infectious cause.
This differential was not explored further as the SPEP results were highly suggestive of a neoplastic condition.