Help please with pyrexic cat now coughing/dyspnoeic

Re: Help please with pyrexic cat now coughing/dyspnoeic

Kate Richardson — Sat, 14 Apr 2012 15:43:03 GMT

Cheers Graham!

Re: Help please with pyrexic cat now coughing/dyspnoeic

Graham Bilbrough — Sat, 14 Apr 2012 15:22:20 GMT

The haematocrit from most haematology analysers is a calculated value (from MCV and RBC concentration).

When obtaining a PCV, we are relying on centrifugal forces (a lot of general practices don't check the performance of their centrifuges!) to estimate the haematocrit. The red blood cells do not pile-up like plates in the kitchen cupboard and there are 'plasma gaps' between the cells. Thus, PCV is a few percentage points higher than the true haematocrit.

Re: Help please with pyrexic cat now coughing/dyspnoeic

Kate Richardson — Sat, 14 Apr 2012 15:11:18 GMT

[quote user="Graham Bilbrough"]Generally, a great idea. But, keep in mind that you would expect the spun PCV to be a few percentage points higher than the calculated haematocrit from an analyser.
[/quote]

Why is that? I have seen this discrepancy several times and always wondered why

Re: Help please with pyrexic cat now coughing/dyspnoeic

Graham Bilbrough — Sat, 14 Apr 2012 14:54:50 GMT

"...if you get a result suggesting anaemia, why not just run a manual PCV to check before sending? Quick and cheap and saves the client money if it obviously has a normal manual pcv."

Generally, a great idea. But, keep in mind that you would expect the spun PCV to be a few percentage points higher than the calculated haematocrit from an analyser.

Re: Help please with pyrexic cat now coughing/dyspnoeic

Graham Bilbrough — Sat, 14 Apr 2012 14:43:34 GMT

"The HGB the prev day was a little higher - 12.5. I wasn't aware that this was what the asterisk meant, but I do know our machine can be inaccurate for haematology and I have had to repeat the haematology with an external lab on a few anaemia cases - and they weren't anaemic!"

How did the Hgb concentration compare between the external lab and the in-clinic analyser? I suspect you will find them to be similar. If you are finding a high proportion of your samples to have a high MCHC (e.g. more than 1 in 5 patients), it may be that your analyser needs attention. This could be something as simple as a "bleach clean". I assume from the order of the results, that this is a LaserCyte. If so, ring our freephone number on Monday and they will be able to check the trend in MCHCs on your LaserCyte via your Internet connection. If you send me an email with your account number (postcode will do) and the point-of-contact at your practice (e.g. the nurse in charge of the lab), I will ask them to make an outgoing call on Monday morning.

Thanks

Re: Help please with pyrexic cat now coughing/dyspnoeic

Kate Richardson — Sat, 14 Apr 2012 14:43:03 GMT

Thanks Graham, great explanation. I didn't know you could tell that just from the figures, so you learn something new everyday

[quote user="Emma Middleton"] I do know our machine can be inaccurate for haematology and I have had to repeat the haematology with an external lab on a few anaemia cases - and they weren't anaemic![/quote]

I know what you mean Emma, generally if our machine says the cbc is normal it usually is, but if it comes up with abnormalities they can mean anything! Regarding anaemia though, if you get a result suggesting anaemia, why not just run a manual PCV to check before sending? Quick and cheap and saves the client money if it obviously has a normal manual pcv.

Re: Help please with pyrexic cat now coughing/dyspnoeic

Graham Bilbrough — Sat, 14 Apr 2012 14:33:37 GMT

The mean corpuscular haemoglobin concentration (MCHC) is a calculated value (whatever the analyser: reference lab or in-house) derived from the haemoglobin concentration of the sample and the concentration of RBCs. Significantly, the analyser does not "know" whether the haemoglobin is within RBCs or in the plasma.

If the sample is haemalysed, the concentration of RBCs in the sample goes down, but the concentration of haemoglobin remains the same. Thus, the analyser reports a high MCHC. Here the MCHC was out of the reference interval. What we don't know is where the haemolysis occurred: during sampling (more of a problem in cats than dogs), in the patient or, with malfunction, in the analyser itself. There is no pathological condition that causes an elevated MCHC.

As a rule-of-thumb, you can also use a ratio of Hgb:HCt. Ignoring the units, you would expect 1 to 3. Here we have 1 to 2.5 and that would be another clue. I am not saying the cat doesn't have mild anaemia (we need to consider the IVFT here!), but the change in reported HCt (0.3 to 0.25) may not reflect what is happening in the patient.

Thanks

Re: Help please with pyrexic cat now coughing/dyspnoeic

Emma Middleton — Sat, 14 Apr 2012 14:22:56 GMT

[quote user="Graham Bilbrough"]

Hi, Emma

As you probably spotted, the subsequent haematology sample is haemolysed and the values with a "*" are to be taken "with a pinch of salt". Was there any change in the cat's haemoglobin concentration?

HCT    * 24.8   %       30-45      ***LOW ***
RBC    * 5.83   x10^12/ 5-10      
HGB    = 10     g/dL    9-15.1    
RETIC  = 14.6   K/uL    

Thanks

Graham

[/quote] The HGB the prev day was a little higher - 12.5. I wasn't aware that this was what the asterisk meant, but I do know our machine can be inaccurate for haematology and I have had to repeat the haematology with an external lab on a few anaemia cases - and they weren't anaemic!

Re: Help please with pyrexic cat now coughing/dyspnoeic

Kate Richardson — Sat, 14 Apr 2012 14:03:08 GMT

Graham, how do you know the sample is haemolysed?

Re: Help please with pyrexic cat now coughing/dyspnoeic

Graham Bilbrough — Sat, 14 Apr 2012 12:44:03 GMT

Hi, Emma

As you probably spotted, the subsequent haematology sample is haemolysed and the values with a "*" are to be taken "with a pinch of salt". Was there any change in the cat's haemoglobin concentration?

HCT    * 24.8   %       30-45      ***LOW ***
RBC    * 5.83   x10^12/ 5-10      
HGB    = 10     g/dL    9-15.1    
RETIC  = 14.6   K/uL    

Thanks

Graham

Re: Help please with pyrexic cat now coughing/dyspnoeic

Kate Richardson — Sat, 14 Apr 2012 12:21:20 GMT

[quote user="Emma Middleton"]Kate - unfortunately we have no bronchodilators in the practice, but this would have been nice to give acutely. [/quote]

Might be worth getting some- injectable terbutaline isn't too expensive if I recall if the practice doesn't want to invest in a 'practice' Aerokat, but worth the investment as quick and easy way to 'test treat' acute dyspnoeas.

Re: Help please with pyrexic cat now coughing/dyspnoeic

Kate Richardson — Sat, 14 Apr 2012 12:15:48 GMT

Good work! Keep us posted

Re: Help please with pyrexic cat now coughing/dyspnoeic

Emma Middleton — Sat, 14 Apr 2012 10:24:59 GMT

Thank you Kate, Sarah and Michael for your input. The FeLV and FIV were negative and so I continued fluids overnight + oral antibiotics. Kate - unfortunately we have no bronchodilators in the practice, but this would have been nice to give acutely.

I was all ready to come in this morning and GA the cat for BAL and place feeding tube, fearing the worst. When I walked in the cat was yowling at me at the front of the cage and looking much brighter, also breathing much more normally, although resps still increased, lungs sound much clearer. She has not eaten anything per se but is licking at Sardines and recovery food, which is a big improvement. Temp now down to 38.5C.

So plan is to keep her hospitalised so we can get the doxycycline into her reliably and hopefully get her eating properly so the owners can crush the tablets and put them in her food.

[quote user="sarah mason"]also could it have a np fb? [/quote]

Hi Sara and thanks for the advice. Yes I was also thinking about possibility of nasopharyngeal FB, aspiration pneumonia. Was going to examine NP this am under GA but as she is so much better I'm holding off for now.

Re: Help please with pyrexic cat now coughing/dyspnoeic

Kate Richardson — Fri, 13 Apr 2012 18:27:17 GMT

If she isn't responding to treatment, then i agree a BAL would be the next step.

I really think this is one case where corticosteroids really aren't indicated at this stage- pyrexic cat with a neutropaenia- too risky in my opinion.

Re: Help please with pyrexic cat now coughing/dyspnoeic

Michael Woodhouse — Fri, 13 Apr 2012 17:20:40 GMT

((from behind sofa - corticosteroids))

Re: Help please with pyrexic cat now coughing/dyspnoeic

sarah mason — Fri, 13 Apr 2012 17:17:47 GMT

it looks bronchial from here, i would get a bal for cytoly and c&s also what is the manual pcv tp and smear exam. could the cat be bleeding or haemolysing? fna the ln, prob reactive in this case, also could it have a np fb? hope you are well x

Re: Help please with pyrexic cat now coughing/dyspnoeic

Kate Richardson — Fri, 13 Apr 2012 17:08:28 GMT

Hi Emma, agree with you re bronchial pattern on rads and looks like a mixed bronchial-interstital pattern as far as I can tell on my computer. Any history of previous coughing? The neutropaenia and pyrexia suggests increased neutrophil consumption so fits with an infectious or inflammatory process. At this stage I would probably try some form of bronchodilator either via an inhaler or injection- have you got injectable terbutaline? and assess response to this, plus oxygen. I would probably change to doxycycline, can be crushed in food so could be syringed in if necessary and only once daily, and try pre-oxygenating prior to tableting if you need to give tabs directly. I would suspect the injection reaction to be a one off, so wouldn't be too worried about injecting if this means less stress for the cat and the meds get in. Obviously need to get the cat eating asap, feeding tube if necessary, plus iv fluids- did you get electrolytes checked to assess potassium as often goes low in sick anorexic cats. I would continue with a nsaid cautiously as long as you make sure the cat is well hydrated. There is mild anaemia as well, so I do wonder about chronicity, and your felv/fiv test results will be interesting (and hopefully negative!) Hope that helps a bit, gotta go and consult now!

Re: Help please with pyrexic cat now coughing/dyspnoeic

Emma Middleton — Fri, 13 Apr 2012 16:22:53 GMT

Forgot to say, I could see the classic bronchial pattern (at least on our digi screen) on the lateral x-ray, don't know if it shows up on here, but I am presuming an infectious aetiology. My concerns are getting antibiotics into this cat without it having a funny turn! I resorted to giving it an amoxyclav tablet just now as oral meds seem to be yielding a lesser reaction. By the way, it only had about 3/4 of its Baytril dose.

Haem results just back - very similar to yesterday in terms of the WBC and neuts (both slightly higher today), but now mild anaemia. HCT yesterday was 30:

WBC    = 3.96   x10^9/L 5.5-19.5   ***LOW ***
LYM    = 1.27   x10^9/L 0.4-6.8   
MONO   = 0.36   x10^9/L 0.15-1.7  
NEU    = 2.03   x10^9/L 2.5-12.5   ***LOW ***
EOS    = 0.27   x10^9/L 0.1-0.79  
BASO   = 0.04   x10^9/L 
%LYM   = 32.1   %       
%MONO  = 9.1    %       
%NEU   = 51.2   %       
%EOS   = 6.7    %       
%BASO  = 0.9    %       
HCT    * 24.8   %       30-45      ***LOW ***
RBC    * 5.83   x10^12/ 5-10      
HGB    = 10     g/dL    9-15.1    
RETIC  = 14.6   K/uL    
%RETIC = 0.3    %       
MCV    * 42.6   fL      41-58     
RDW    = 19.5   %       17.3-22   
MCHC   - --.--  g/dL    
MCH    = 17.2   pg      12-20     
PLT    * 406    K/uL    175-600   
MPV    * 12.6   fL      
PCT    * 0.51   %       
PDW    = 25     %       
Value Out of Range