Presentation on theme: "Instructions for Cases 1.Do NOT print this outit will waste a lot of paper. 2.Clicking on the blue underlined questions will take you to the answer. On."— Presentation transcript:
Instructions for Cases 1.Do NOT print this outit will waste a lot of paper. 2.Clicking on the blue underlined questions will take you to the answer. On the answer slide, click return to case. 3.On the diagnostics page, every test is not necessary. Choose only those that you feel will appropriately narrow your differential list or affect your treatment plan. Click on the test to obtain the results and my justification for performing (or not performing) each test. 4.Similarly, not all the offered treatments and preventions are appropriate or necessary. Pick those that you feel are best.
Background Signalment: 3 year old Brown Swiss cow. 12 days postpartum History: Found down in the pasture this afternoon. Could stand and walk slowly when encouraged. Severely depressed. Herd is vaccinated annually with a killed respiratory disease/lepto vaccine and clostridial vaccine.
Physical Exam: T-97.8F, P-115, R-80. No rumen contractions. Ping noted on right flank approximately 10 inches in diameter and centered over 13 th rib. What is the most likely cause of a ping in this location and what should we do about it?
Small pings in the dorso-cranial right flank near the 13 th rib are most commonly due to gas in the spiral colon. This is a normal finding and no treatment is needed. Return to case
Physical exam, cont.: Eyes are approximately 6mm recessed. Right prefemoral and right supramammary lymph nodes are enlarged. Right rear quarter is swollen, red, and painful. Milk from that quarter is watery with some clumps. Rectal exam: Uterus is appropriately involuted for 12 days in milk. Remainder of physical exam is unremarkable. What is the significance of eyeball recession? What is this cows problem list? Based on this problem list, what are your differentials?
Eyeball recession is one of the best measures of dehydration in cattle. Estimate the recession of the eye at the medial canthus in millimeters. Multiply this number by 2 and you get a reasonable approximation of percent dehydration. For example in this case, we estimated the eyeball recession to be 6mm, so the cow is 12% dehydrated (6mm x 2 = 12 % dehydrated). Note that dehydration of less than 6% is probably not clinically apparent, and dehydration much more than 12-14% generally equals death. Return to case Measure this distance in millimeters
Problem list: Abnormal milk in right rear quarter Inflamed right rear quarter Regional lymphadenopathy Weakness/depression Tachycardia Hypothermia Dehydration Return to case
Differential Diagnoses: Acute Toxic Mastitis Salmonellosis with unrelated mastitis Abomasal volvulus with unrelated mastitis Return to case It should be relatively clear that this is a case of acute toxic mastitis and the other two differentials are rather unlikely. Salmonellosis will cause similar signs of sepsis, but this cow does not have diarrhea. Similarly, a cow with an abomasal volvulus will have similar clinical signssevere dehydration, tachycardia, and weaknessbut the ping on the right is not consistent with an abomasal ping. Which bacteria are most commonly associated with acute toxic mastitis? Are they environmental or contagious pathogens?
Gram negative bacteria are most commonly associated with acute toxic mastits. E. coli and Klebsiella spp. are the typical organisms isolated. Both are environmental pathogens, and Klebsiella is specifically associated with sawdust bedding. Return to differential diagnoses list
Diagnostic Work Up Complete blood count Chemistry panel Sterile milk culture from affected quarter Abdominal ultrasound Gram stain of milk from affected quarter California mastitis test Abdominal exploratory Serial Salmonella fecal cultures Based on your findings, what is your diagnosis?
CBC TestResultReference Range WBC 6404000-12000 PCV3326-44 Plasma Prot6.87-8.5 Fibrinogen300300-700 Seg Neuts26600-4000 Band Neuts00-120 Lymphs5892500-7500 Monocytes625-840 Eosinophils130-2400 Where did all the neutrophils go? This test is probably not necessary, as it will not affect your diagnosis, treatment plan, or prognosis. Nonetheless, the results are interesting and classic for this disease. Return to case
Neutrophils are lost into the mammary gland to some degree, but the biggest cause of neutropenia in septic animals is due to the margination of neutrophils in the vasculaturethey become sticky and start attaching to the endothelium as they become activated. Return to case
Chemistry Panel Test ResultReference Range Glucose8646-76 Urea Nitrogen245-20 Creatinine1.40.7-2.0 Phosphorus6.34.7-8.3 Calcium8.68.7-10.9 Magnesium2.01.9-2.7 Total Prot6.16.7-8.9 Albumin3.42.7-3.6 Globulin2.73.5-5.9 Total Bilirubin0.6<0.3 ALP6422.4-114.1 AST7546-87 GGT327-36 CK36475-558 Sodium139138-147 Potassium4.34-5.7 Chloride9697-107 Bicarbonate2518-27 A chemistry is not necessary to come to this diagnosis, and probably not worth the expense. Measuring calcium could be helpful in ruling in or out hypocalcemia as a contributing factor to the cows weakness. Similarly, hepatic lipidosis could also be (somewhat poorly) assessed from a chemistry panel. Neither of these answers though will impact your main diagnosis, but could affect your fluid choice. Return to case
Sterile Milk Culture This test will confirm your primary differential, and can help in making recommendations to the farm for control of this disease. The downside of culture is that it takes a couple days, so it is not very helpful in guiding the initial treatment of this cow. Results: No Growth Nothing grew? So the cow doesnt have mastitis? Return to case
No growth results are relatively common with Gram negative mastitis cases. So these results could actually support your suspicion. Return to case
Gram stain of milk This test will give you immediate results (unlike culture), but you will not be able to identify a species of bacteria. It is useful in confirming your diagnosis, and guiding treatment as not all antibiotics will be effective against Gram negative organisms. Results: Multiple Gram negative rods seen Return to case
Abdominal Ultrasound This test is not warranted at this time. The location of the ping and rectal exam findings are sufficient to determine what the ping is. Furthermore, ultrasound diagnosis of pings is difficult as they are caused by gas and fluid filled structures, and the gas precludes easy identification of the pinging structure. Return to case
California Mastitis Test A CMT is extremely useful in identifying subclinical mastitis, but is not necessary in this case. You know that the cow has mastitis simply by looking at the milk. Return to case
Abdominal Exploratory While exploratories are reasonable diagnostics in many bovine cases, this cow does not need surgery. The location of the ping and the negative rectal exam findings allows you to determine that this is not a surgical problem. Return to case
Serial Salmonella Cultures As salmonellosis is unlikely, this should not be pursued at this time. Return to case
Diagnosis Acute Toxic Gram Negative Mastitis If you arrived at this diagnosis without any of the diagnostic tests, that is fine. The signs are pretty classic for this disease, though a culture of the milk is a good idea for any cow with clinical mastitis. Now that we have a diagnosis, what should we do about it?
Treatment Intramammary Spectramast (ceftiofur) Intramammary ToDAY (cephaparin) Intramammary Gentocin (gentamicin) Subcutaneous Naxcel (ceftiofur) Subcutaneous Baytril (enrofloxacin) IV hypertonic saline IV lactated ringers solution Oral electrolyte solution Frequent stripping of milk from the infected quarter Case Outcome
IMM Spectramast Use of intramammary antibiotics in cases of Gram negative mastitis is controversial, particularly in cases such as this in which there is no growth. Treatment may or may not impact resolution of this case, but appears to decrease recurrence. In this particular case in which the cow is particularly sick, I would generally opt to treat. Of the given options, Spectramast (ceftiofur) is the only drug that has both an appropriate spectrum of activity (cephaparin is not effective against G- pathogens) and is legal (there is no IMM gentamicin product, so any use would be extralabel and not appropriate since there is an approved drug for this disease). Return to case
IMM ToDAY Cephaparin is not effective against G- pathogens, so it would not be an appropriate antibiotic choice. Return to case
IMM Gentocin While gentamicin will kill G- pathogens, there is no IMM gentamicin product. This extralabel use would be inappropriate as there are approved IMM antibiotics that would likely be effective against these pathogens. Return to case
SQ Naxcel Are cows with toxic mastitis systemically ill due to absorption of endotoxin or whole bacteria (endotoxemic vs. septicemic)? Based on these findings, it is prudent to treat cows with systemic antibiotics that have a G- spectrum. Naxcel will kill G- pathogens and is a reasonable choice in this case. Return to case
SQ Baytril Enrofloxacin has a G- spectrum, but is not labeled for treatment of mastitis. Extralabel use of this drug is prohibited, so go directly to Jail, do not pass Go, and do not collect $200. Return to case
IV Hypertonic Saline Based on this cows clinical signs of shock (hypothermia, tachycardia, tachypnea), rapid plasma volume expansion is needed. This is best accomplished by administering 4-5 ml/kg of hypertonic saline over 5 minutes. In order to prolong this effect, administration of a large volume of oral fluids is necessary after administering hypertonic solutions. Return to case
IV LRS Generally sick adult ruminants become alkalotic, so as a rule LRS would not be the best fluid choice. Furthermore, the volume of isotonic fluids needed for this cow would be impractical to administer in most situations. Return to case
Oral Fluids Due to the severe dehydration and shock in this cow, oral fluids alone would not rehydrate the cow quickly enough. Ideally, oral fluids would be combined with IV hypertonic saline. Return to case
Frequent Milking This treatment is based on the classic theory, Better out than in. The idea is that repeatedly milking the affected quarter may increase the rate at which the pathogen is expelled. This has been difficult to confirm experimentally, but certainly does no harm, and may be helpful. It is time consuming, and may not always be practical on every farm. Return to case
Case Outcome Due to your prompt administration of IV and oral fluids, and IMM and SQ ceftiofur, the cow is improving. The farmer is sufficiently impressed to consider listening to any preventative recommendations that you have. So… What about the rest of the herd? What recommendations do you make?
Preventative Measures Gram negative core antigen vaccine Switch to sand bedding Wash any manure off udder prior to milking Switch to Albadry (penicillin/novobiocin) at dry off
Gram negative vaccine Significant research has shown that G- core antigen vaccines are effective in decreasing the severity of G- mastitis though the incidence may or may not decrease. Economically, this is still an effective preventative strategy as it will decrease the number of cows that die from toxic mastitis or need intensive therapy like this cow. Return to case
Sand Bedding Sand bedding is consistently the best bedding for dairy cows in freestall barns. It is the most comfortable, drains well, and does not support bacterial growth. Switching from an organic bedding (sawdust, straw, composted manure) to sand will help prevent G- mastitis. Sand is more expensive than the other options and does pose some difficulties in regards to manure management. Return to case
Washing the Udder Use of water to wash the udder is associated with an increase in G- mastitis. The teats should be cleaned, but washing the udder only washes pathogens from the udder down onto the teats. Return to case
Albadry at dryoff Dry cow antibiotics help prevent G- infections during the dry period, but have no effect on the incidence of G- mastitis during lactation. Therefore, changing the dry cow therapy would be of no value in this case. Return to case
This is the end of case #1. Please contact me at firstname.lastname@example.org if you have any questions or comments concerning this case. I appreciate any suggestions that you may have. email@example.com