LABOKLIN aktuell 2012 – LABOKLIN Europe

Anti-Mullerian Hormone

Laboklin — Wed, 02 May 2012 06:35:47 +0000

– Differentiation: Castrated, Uncastrated or Cryptorchid

– Diagnosis of Granulosa Cell Tumours in Mares

The Anti-Müllerian Hormone (AMH) is a glycoprotein that plays an important role in the sex differentiation during embryogenesis.

In male animals testosterone is responsible for the development of the Wolffian ducts, whereas AMH is needed to prevent the development of the mullerian ducts into the uterus and other mullerian structures.

In female animals AMH is not produced by the gonads during sex differentiation in early gestation, so the mullerian ducts automatically develop and the normal development of the female genitals occurs. In female animals, AMH is expressed by granulosa cells of the ovary controlling the formation of primary follicles by inhibiting excessive follicular recruitment by FSH.

Horse

In human medicine AMH is used to diagnose Granulosa cell tumours (GCT) (Fig. 1). As GCT is the most frequent diagnosed tumour of the equine female genitals (~85% of tumours found in the reproductive organs), it was obvious to try to establish this diagnostic test for mares as well. This idea was presented by B. A. Ball et al., at the AAEP Annual Convention in November 2011, which presented equine results. They had successfully been able to establish and validate a human test also for horses.

AMH stays the same during the reproductive cycle, but show individual differences between mares (0.22–2.94 ng/mL).
The AMH concentration is slightly higher in nonpregnant mares than pregnant mares.
Ovariectomized mares show a significantly lower AMH level (<0.1 ng/ml) and very importantly mares with granulosa cell tumours show significantly higher hormone concentration (>14.0 ng/ml) than normal mares.

For diagnosing Granulosa cell tumours the assay has a sensitivity of 95%, which is significantly higher than the other hormone tests previously used; Inhibin concentration has a sensitivity of 85%, Testosterone only 55% sensitivity. Other ovarian tumours (e.g. carcinoma, adenoma) are not detected by the AMH test.

In stallions AMH is produced by the Sertoli cells and remains high through puberty where it then declines to low levels with increasing testosterone production. Therefore stallions and cryptorchid can clearly be distinguished from castrated horses by measuring the AMH concentration (Tab. 1). AMH is in male animals a useful biomarker for active testicular tissue therefore useful to diagnose cryptorchidism. This test can even be used in young castrated animals – opposite to for instance the oestrone sulphate test.

Dog & Cats

Neutered versus intact is very difficult to determine in female animals, especially in animals with an unknown history (e.g. stray dogs). Here the AMH test can again be useful in both bitches and female cats. The bitches should be older than 6 months when tested. The time in cycle (also anoestrus) has on the other hand no influence on the result. The necessity to perform a dynamic test is with the new AMH test available hereby eliminated!
The same applies to both male dogs and cats: AMH determination can be used to diagnose cryptorchidism. As the AMH secretion take place in the Sertoli cells, AMH concentrations above the reference value indicate presence of testicular tissue (Tab. 1).

AMH Test & Interpretation

The AMH test is an ELISA test that (for now) is carried out once a week in our lab. Useful material is serum or lithium-heparin-plasma. The sample should be promptly centrifuged (for serum, right after coagulation) and cell-free pipetted. It is recommended to cool the sample before transportation and ship cooled if warm weather.

Anti-Mullerian Hormone

Take a Look at These Wild Slides – Haematology of Reptiles

Laboklin — Wed, 18 Apr 2012 12:14:17 +0000

Over the last few decades the popularity of reptiles as pets has increased. This trend is clearly reflected in the increasing number of exotic trade shows and the availability of reptiles in many pet shops. The animals are offered at low prices or even as an „all-inclusive set“ and purchased by unknowing pet lovers. Frequently the rude awakenings follow immediately – the reptiles become ill and are presented at the veterinary practice more and more often.

This of course provides a welcome variety in everyday practice life, but it also poses a new challenge to the practitioner.

There are some difficulties arising from differences between reptiles and the common mammals: the physiology of the ectothermic animals, their reaction to medications, available laboratory tests and last but not least a different morphology of blood cells.

Blood sampling

The blood sampling technique varies depending on the patient species (Tab. 1).Techniques such as clipping of toenails or tail tips are rendered obsolete and are no alternative to professional venipuncture.

General guidelines:

– A blood volume of 0.5% up to 0.8% of the body weight can be sampled safely from a healthy, normally hydrated animal

– The anticoagulant of choice is Li-Heparin, as EDTA may cause haemolysis, especially in tortoises and turtles

– Immediate preparation of a blood smear in order to avoid pre-analytical errors like the deterioration or clumping of blood cells

(Tab. 1)

Sample analysisk

There is a fundamental difference between mammalian and reptilian blood cells: In reptiles all blood cells are nucleated, whereas in mammals only leukocytes and erythroid precursors show a nucleus (Fig.2).

In general, haematology analysers first count In general, haematology analysers first count erythrocytes and thrombocytes, then lyse these cells and subsequently count the nucleated leukocytes. Unfortunately the nuclei of reptilian erythrocytes and thrombocytes do not lyse and therefore a reliable and exact separation of the different cell lines is not possible. Hence automated cell counters are not applicable for reptile blood samples.

Blood cell counts are performed by manual methods:

One possibility is the use of a haemocytometer with different staining and solution systems (e.g. the Unopette system or Natt and Herrick’s solution). These techniques are time consuming and results actually show a higher variability than results of automated methods.

Another manual technique is the estimation of leukocytes and thrombocytes using a stained blood smear. With this method the variability of results is also high, but the procedure is rapid and simply performed with a little bit of experience. Using the 40x objective (400x magnification, if required 100x objective/ 1000x magnification) leukocytes are counted in at least 10 fields of the blood smear. The average cell count per field is calculated and multiplied by the square of the magnification of the used objective (i.e. with 400x magnification by factor 1600, with 1000x magnification by factor 10000). The result is the number of cells per μl blood.

A small calculation example:

7 Leukocytes/400x field
7×1600=11200
The leukocyte count is 11200/μl

Thrombocytes are counted in the same way with the 100x objective (1000x magnification) but multiplied by factor 15000.
Furthermore the differential leukocyte count and morphology of the blood cells are obtained by microscopic examination of blood smears.
It is not possible to estimate the erythrocyte number. The packed cell volume (PCV) is determined by microhaematocrit centrifugation as in mammals. Haemoglobin concentration can be measured by haematology analysers.

Blood Cell Morphology

Erythrocytes of reptiles are ellipsoidal and have a centrally positioned nucleus. Depending on the stain used, the colour of the cytoplasm ranges from orange to pink or pale violet. Round basophilic or irregular clear inclusions (Fig. 3) are regularly found in the otherwise homogenous cytoplasm. In general these findings represent artefacts of slide preparation, staining or a prolonged drying period. Slight anisocytosis and polychromasia are normal in most reptiles. Increased numbers of polychromatic (juvenile) erythrocytes are found in regenerative anaemia, during ecdysis and in young animals.

In some cases of regenerative anaemia, massive inflammation or post hibernation erythroid precursors may be found (Fig.4). These are not necessarily a sign of bone marrow disease as in mammals.

Thrombocytes are frequently aggregated on reptile blood smears which complicate the estimation of their number. However, if some aggregates (Fig. 5) are present the thrombocyte number is probably normal. The morphology of reptilian thrombocytes is variable, but they are always nucleated and mostly ellipsoid (Fig. 5). The cytoplasm is usually colourless, but can stain pale blue or pale violet. If the thrombocytes round up (e.g. because of activation) they can easily be confused with small lymphocytes (Fig. 6).

Reptilian leukocytes are classified as heterophils, eosinophils, basophils, lymphocytes, monocytes and azurophils. Classification is occasionally difficult, because the morphology of the blood cells sometimes varies significantly between reptilian species, as well as between subspecies of one species. The differential leukocyte count naturally exhibits a high variation, on the one hand between individuals due to season, temperature and partly gender, on the other hand due to species differences. Some reptile species show a lymphocyte pre-dominant haemogram, i.e. lymphocytes are the most prevalent cell (e.g. bearded dragon, iguana, tortoises), whereas in others granulocytes predominate.

Lymphocytes resemble those of mammals and are easily differentiated from other leukocytes. They have a round nucleus with dark chromatin and only a scant amount of basophilic cytoplasm.

Lymphocytosis occurs during inflammations and viral infections.
The function of heterophils is analogous to the function of neutrophils in mammals. Heterophilic granules stain orange to pink with quick stains. Sometimes granules dissolve and make the cytoplasm appear eosinophilic (Fig. 7, lower left). The differentiation of heterophilic and eosinophilic granules only by their colour is sometimes impossible. However, heterophils are mostly of larger size and the granules are long, while eosinophilic granules are almost always round.

The nucleus of heterophils is round in some species (e.g. tortoises, crocodiles, snakes); other species (e.g. iguanas, chameleons, dragons) show a segmented nucleus in mature cells.

Heterophilia is primarily associated with inflammation (often together with monocytosis). Other causes are stress, paraneoplastic syndrome or leukaemia (uncommon). In severe, acute inflammation animals that normally have segmented heterophils can show a left shift (bands). In extreme cases toxic changes are also visible: loss of physiologic granules, basophilic and/or vacuolated cytoplasm and toxic granulation (Fig. 8).

Eosinophils display bright red or orange, round granules in most reptiles. Some species (e.g. green iguana, bearded dragon) show also small and round, but blue to grey granules. The number of eosinophils varies highly between species (chelonians often show high numbers) and with various factors like season and parasitic infestation (Fig. 9).

Basophils have many dark purple staining granules that sometimes obscure the eccentrically placed nucleus. Using quick stains basophils often show only few granules or appear vacuolated (Fig. 10).

Monocytes have variably shaped nuclei, as in mammals. They have moderately blue-grey cytoplasm that can be clearly vacuolated in activated cells. Monocytosis is present in various inflammatory conditions, especially in granulomatous forms (Fig. 11).

Melanomacrophages are a special kind of monocytes in lower vertebrates that have phagocytized melanin granules. They can be found in inflammatory disease, especially in dermatitis (Fig. 12).

The origin of azurophils is an intensely debated topic. Morphologically the cells look like monocytes with dust-like eosinophilic granules in the cytoplasm (Fig. 13). Some authors classify them as subgroup of monocytes. Other investigators regard them as a separate cell type. In addition, the clinical significance of azurophils is still unclear.

Take a Look at These Wild Slides – Haematology of Reptiles

Coughing, Sneezing, Hoarsening – Infectious Diseases of the Canine Respiratory System

Laboklin — Thu, 15 Mar 2012 15:16:57 +0000

Multiple Factor Disease “Kennel Cough”

The very common airway disease, known as “Infectious Canine Laryngo-tracheitis” or „Kennel Cough“ is characterized by acute onset of an extreme rough, sometimes convulsive cough. A multi-factor disease is your first suspicion, involving both viral and bacterial pathogens. Predisposing factors are high population density, as can be seen in shelters, kennels or large breeding facilities. Here is, as at dog schools or dog pensions, a very high infection pressure. Animals at all ages can be affected, although puppies between 6 weeks and 6 months are affected the most and most severely ill.

On top of the list of pathogens are the viral once, such as Canine Adeno virus Type 2 (CAV-2) and Canine Parainfluenza virus (CPiV). An infection with CAV-1, the pathogen of Hepatitis Contagiosa Canis (HCC) can in mild cases also cause respiratory symptoms. More rarely are the Canine Influenza virus, Canine Distemper virus (CDV) or Canine Herpes virus (CHV) involved in the disease. The primary bacterial pathogen is the Bordetella bronchiseptica. After the respiratory epithelia cell damage caused by the above mentioned pathogens, secondary bacteria or mycoplasma infections can create more severe respiratory disease. As secondary pathogens Pseudomonas spp., E.coli, Klebsiella, Pasteurella and Streptococci can be seen.

In uncomplicated cases a dry or cramping cough is the only symptom seen, which can be stress-induced or induced by pressure on the larynx. The trachea is easily triggered. More severe cases are presented with anorexia, moist productive cough, lethargy, dyspnoea, tachypnoea and/or weakness. Fever is usually only moderate if present.

Correct diagnose is made from the history (sudden onset of symptoms, possible exposure (contact to other dogs), lack of immunization, etc.) combined with the clinical symptoms. Viral pathogens can, especially in the early phase, be detected by means of PCR from a nasal- or throat swab. As bacterial infections are the cause of the more severe symptoms, a bacteriology examination including culture and subsequently antibiogram is crucial. A culture swab taken deep in the throat or from a tracheal- or broncho-alveolar lavage (BAL) is needed. Sampling must be done before any antibiotics are given. (Fig. 1)

Antibody detection is not always as useful due to the huge distribution of these pathogens in the dog population, and one cannot distinguish between a vaccination or infection titre. A second antibody titre test after 2-3 weeks is therefore required to indicate a current infection in most cases.

Therapy consists in most cases of antibiotics according to the antibiogram for a minimum of 14 days. Cough medicine (e.g. Butorphanole) should only be given to dry coughs. Important is strict rest for at least 2-3 weeks; in severe cases even longer. The owner should be informed that their dogs is contagious and should be kept away from other dogs. Especially by Bordetella bronchiseptica infections as it can persists in the respiratory tract for several months after recovery. As prophylaxes several vaccines are available.

Canine Parainfluenza virus (CPiV)

CPiV is a large enveloped RNA-Virus belonging to the Paramyxo virus family. It cannot replicate in macrophages and is therefore only to be found in the upper respiratory system. Mono-infections run rather unapparent but can be with respiratory symptoms like nasal discharge or cough.

Shedding of virus occurs mostly in the early stage of infection (6-8 days p.i.) in oro-nasal secretions. Detection is possible by PCR test.

Canines Adeno virus (CAV)

CAV is a non-enveloped DNA-virus with relative high tenacity. Adeno viruses are strictly species specific. CAV-1 and CAV-2 are genetically and anti-genetically close related; their antibodies show cross protectivity. Their difference lies in their organ tropism. CAV-2 show affinity for the respiratory tract: the virus replicates in the ciliated epithelium. Opposite the CAV-1, CAV-2 does not spread into a generalized infection. The clinical symptoms are often mild.

CAV-2 are excreted in nasal secrete up to approximately 9 days p.i. Contamination occurs through aerosols and direct contact. Detection is possible by PCR test.

Canine Distemper virus (CDV)

Canine Distemper virus (CDV) is a high-contagious RNA-Virus which affects several species in the order Carnivora. Besides dogs also fox, ferret, raccoon, otter and more can be infected. It causes acute to chronic general disease with different symptoms depending on the immune status of the animal:

GI-symptoms: Diarrhoea, vomitus
Respiratory symptoms: Conjunctivitis, coughing, bronchitis through to catarrhal broncho-pneumonia
CNS-symptoms: Blindness, ataxia, behavior changes, tonical-clonical cramps
Cutaneous symptoms: Hyperkeratosis of the feet or nares

Virus reservoir is clinical unapparent infected animals. Contamination occurs through direct contact or by aerosols. The initial virus replication occurs in the mono-nucleated cells in the local lymph nodes or tonsils wherefrom it evolves to a cell-associated viremia and target organ infection.

Young dogs from 6 months age are most susceptible. Typical symptoms are intermittent fiver. Virus are excreted with every kind of body secrete from day 5 p.i. The direct detection for diagnosis is possible by PCR test.

Canine Herpes virus (CHV)

Canine Herpes virus (CHV) infection is a very per-acute disease in young puppies; it can cause abortion if the infection is intrauterine, but CHV is in adult animals mostly an unapparent infection with only mild respiratory symptoms like rhinitis and conjunctivitis, if any.

Herpes virus is a large enveloped DNA-virus which is highly host-specific. Typical herpes virus infections are life-long latent infections. In the latent phase virus is situated in the neurons of the sensory ganglia. A sporadic reactivation of a latent infection can occur due to stress or immune suppression (e.g. Glucocorticoids), whereby CHV are shed and can be found in oro-nasal and vaginal secretions.

Contamination occur mostly oro-nasal through direct contact with an infected animal as intrauterine. Thereafter virus replication occurs in the mucous membrane of the upper respiratory tract and in the tonsils. Virus replication occurs at an optimum temperature of 37°C. Therefore, in puppies with a reduced body temperature, a viremia and subsequently a haemorrhagic-necrotizing infection of the inner organs occur. In older puppies where the body temperature regulation is fully functional the infection is limited to the upper respiratory tract. Virus detection by PCR test of nasal- or throat swab can be useful in active phases of infection. Alternatively PCR test on liver tissue upon autopsy or uterus swab from the aborting bitch.

Bordetella bronchiseptica

Bordetella bronchiseptica is a small, aerobe and mobile gram-negative bacteria. (Fig. 2)

It has a high affinity for ciliated epithelium in the respiratory tract and produces a row of toxins which paralyzes the cilia, inhibits the mucociliary clearance and decreases the phagocytosis. That is the reason why Bordetella bronchiseptica, besides it primary pathogenicity, plays an important role in facilitating secondary bacterial infections. It is multi-hostel (Zoonose) and can be contagious from dogs to cats and exotics and vice-versa.

Contamination occurs through droplet infection and close contact. The incubation time is 2-14 days. Clinical symptoms are predominately coughing and serous nasal- or eye secretion but otherwise unaffected.

Bordetella bronchiseptica causes a strong local immune response but as a facultative intracellular organism, it can escape the specific immune response and persist in the respiratory tract for a long period of time. Dogs which have been infected with Bordetella bronchiseptica have immunity for at least 6 months thereafter.

Detection of Bordetella bronchiseptica is mostly done by means of a PCR profile, where you profit from the extreme high sensitivity of the test method. A culture with subsequent antibiogram is recommended for correct therapy, as Bordetella bronchiseptica resistance to Doxycycline and Tetracycline has been described. Therapy should be continued until at least 1 week end of symptoms. As prophylaxes an intranasal life vaccine is available. After vaccination the bacteria enters the respiratory tract for several month and causes a local immunity. A vaccination during antibiotic therapy is therefore worthless.

Mycoplasma spp.

Mycoplasmas are very small organism without a cell wall which replicates independently through mitosis. Mycoplasmas require direct contact with host cells in order to have a functional metabolism. Therefore a special culture medium is needed for both transportation and cultivation and the organism also grow much slower than bacteria in the lab. Mycoplasmas are often not very virulent, but on the other hand very capable of avoiding the infected animal’s immune response. Infections are often secondary to other diseases. Pathogenic Mycoplasmas show a degree of host specificity.

Mycoplasma-commensal can be found in the canine naso-pharynx mucous membrane but is normally not to be found in the lower respiratory tract. Here they can cause cilia stasis, loss of cilia or even purulent bronchopneumonia if the lower respiratory tract has been pre-damaged by e.g. virus. Especially Mycoplasma cynos can be found in conjunction with respiratory disease in dogs.

Diagnostic samples should be taken from the lower respiratory tract. PCR test can be performed directly from the BAL-sample or from a dry swab.

Due to lack of a cell wall, only antibiotics impacting the protein- or nuclear acid syntheses are effective, as gyrase-inhibitors, macrolides- or tetracycline antibiotics. Please notice that therapy must be carried out for at least 4-6 weeks.

Streptococcus equi subsp. zooepidemicus

During the past years more and more reports of acute haemorrhagic pneumonia have been reported in dogs. Mostly dogs in large groups are affected (e.g. kennels, shelters). Responsible pathogen was identified as being Streptococcus equi subsp. zooepidemicus. Some were co-infections with the above described virus which also here can act as a precursor for secondary bacterial infections.

Initial the dogs show only nasal discharge and moist coughing, but later tachypnoea, anorexia and fiver sets in. Sometimes even a massive dyspnoea occur due to a haemorrhagic pleural effusion and death will follow within 2 days after first clinical symptoms are seen; mortality rate is high despite intensive therapy. The exact pathogenesis is still unclear.

The most suited material for culture or PCR tests are tracheal- or broncho-alveolar lavage (BAL) or lung tissue from death animals. As Streptococcus equi subsp. zooepidemicus is shed through respiratory secretes also nasal- or throat swabs can be used for PCR. Sick animals must in all cases be kept in isolation to avoid infecting other dogs.

Therapy should be initiated as soon as possible. Drugs of choice are Cephalosporin-, ß-Lactam- or Macrolide-antibiotics with a guarded prognosis.
Besides the above mentioned pathogens several mycological or parasitic infections can occasional play a role in canine respiratory disease.

Summery

For the diagnosis of canine infectious diseases causing coughing, especially in young animals with contact to other dogs, the following laboratory tests are significant:

• PCR Test:
Especially valuable in detecting virus, but useful for many pathogen bacteria as well. Please notice that no antibiogram is available after a PCR test.

Material needed: Tracheal- or BAL-sample, swab without medium or in rare cases a tissue sample.

• Bacteriology culture:
Culture with subsequent antibiogram for a correct therapy. Every pathogen found in a BAL-sample is usually relevant.

Material needed: Tracheal- or BAL-sample or swab with transport medium

Coughing, Sneezing, Hoarsening – Infectious Diseases of the Canine Respiratory System

Proliferations/Neoplasia of the Oral Cavity in Dogs and Cats

Laboklin — Mon, 12 Mar 2012 12:54:22 +0000

Lesions in the oral cavity are seen quite frequent in both dogs and cats. From a clinical point of view it is of great importance to know if the lesions are caused by an infection or neoplasia.
In this LABOKLIN Aktuell examples of both infectious and tumorous lesions in the oral cavity are described.

Eosinophil Ulcers

This disease is seen in cats and some dog breeds and belongs to the eosinophil granuloma complex. The lesions can be solitude or multiple. In dogs raised ulcerated plaques are most often seen, whereas cats show well-defined, ulcerated lesions with raised margins.

The aetiology is unclear, but the responsiveness to corticoids indicates an immune mediated pathogenesis.

Due to the unspecific clinical picture a histopathology examination is needed to determine the correct diagnosis. The results are characterized by the presence of eosinophil granulocytes as well as collagenolysis.

Plasmacytic Stomatitis

This disease affects cats, but rarely dogs, and presents itself with erythematous extensive proliferations. Histopathological it can be determined by a submucosal infiltration with plasma cells. The aetiology is thought to be immunological due to the increased immunoglobulin level in the blood. The Plasmacytic Stomatitis diagnose can only be differentiated from other lesions by histopathology.

Feline Ulcerative Stomatitis

This is seen in cats in the entire oral cavity but predominately in the deep throat and jaw angle. The aetiology is unclear. A microbial flora alteration is discussed as the cause, but for now it is believed that Feline Calici virus and Feline Herpes virus 1 are involved. The histopathology picture is non-specific but further examinations using PCR can be used in identifying the pathogen (see Fig. 1).

Besides infections also Neoplasia can cause proliferations and swellings. Tumours of the teeth (Odontoma, Cementoma) and the salivary glands will not be covered here.

Epulis

Epulis are considered to be hyperplasia and not neoplasia. The affected animals have rough, often multiple proliferations in their oral cavity.

Histopathological there are two forms: Epulis Fibromatosa and Epulis Ossificans, although mix-forms can occur. Both show connective tissue proliferations. The Epulis Ossificans produces additional osteoid and well-differentiated trabeculae. The clinical picture is identical. Invasive growth is not known, but as a complete excision can be very difficult renewed growth can occur.

A macroscopic differentiation between Epulis and Canine Acanthomatous Ameloblastoma is not possible, so a histopathology exam is crucial.

Canine Acanthomatous Ameloblastoma

This is a tumour originated from the odontogenic epithelium (see Fig. 2) (Earlier: Acanthomatous Epulis). The histopathological exam is here particularly important in differentiating squamous cell carcinoma from ameloblastoma and epulis, as the ameloblastoma unlike the epulis show a local invasive growth but do not metastasize and therefore has a better prognosis than the squamous cell carcinoma.

Papilloma

Papillomas are benign tumours originated from squamous epithelia. Macroscopic wart-like structures with a cauliflower-like surface are seen. There are two forms: In puppies and young dogs multiple viral papillomas can be seen which can spontaneous regress. The second form appears mostly in elderly dogs and with solitary lesions. Papilloma virae as cause for this form is controversial.

Prognosis is for both forms usually good, but in rare cases a malignant transformation can occur, with irregular deep epithelia taps showing in the histopathology preparation.

Squamous Cell Carcinoma

This is a malignant tumour form of the squamous epithelia cell. It is the most common tumour form in the feline oral cavity and the second common in the canine.

The tumour can invade both bone and soft tissue structures. The bigger the tumour is upon removal the poorer the prognosis.

In cats the tumours are macroscopical irregular red-grey colour lumps with a crumbly consistency. Often they ulcerate.

In dogs the tonsils but also the gingiva is affected.

Both local and remote metastases are described in dogs and cats.

Melanoma

Melanocytic tumours in the oral cavity are most often malignant. They are easily recognized by their black colour. The prognosis is poor, as early metastasis to the regional lymph nodes, lung, liver, kidney, brain and other organs often occur.

Fibrosarcoma

Fibrosarcomas are mesenchyme tumours originated from connective tissue. Macroscopical they are grey-red, rough proliferations. Fibrosarcomas are highly invasive leading to osteolysis complicating removal. Metastases can be seen in the lymph nodes and lungs.

Osteosarcoma

Bone distensions can be seen by osteosarcomas. The lytic and proliferating processes with bone remodelling can be difficult to distinguish from infectious or traumatic lesions – even histopathological. Often a diagnosis has to be made by a combination of clinical symptoms, images (e.g. x-rays) and histopathology lesions.

Conclusion

As many lesions of the oral cavity macroscopical have the same appearance a histopathology exam is recommended by every case. Prior to any resection, possible differential diagnosis should be considered in order to choose the most appropriate resection technique. Furthermore it is recommended to check the resectionlines histological to determine if all affected tissue has been thoroughly removed.

Proliferations/Neoplasia of the Oral Cavity in Dogs and Cats

Glucocorticoids and their Influence on Allergy Testing

Laboklin — Mon, 09 Jan 2012 14:45:31 +0000

Glucocorticoids are used commonly in many different areas of veterinary medicine. They are necessary drugs in many situations, but should always be used advisedly and with the right dosage. However, you should always be aware of their effects, their side effects to the animal body and their strong influence on laboratory examinations, which we will cover in this edition of the LABOKLIN Aktuell.

In the table 1 are listed different duration times of various Glucocorticoids. Short acting means <12h, intermediate acting means 12-36h and long acting means >36h. The long term effect of cortisone depends on combination of the base and the ester of the steroid, like the long acting glucocorticoids Paramethasone, Betamethasone and Dexamethasone, which duration time lies clearly over 36 hours.

The modality of administering cortisone also has an influence on its efficacy and duration of action. In general there is the possibility to apply Glucocorticoids orally, intramuscularly, subcutaneously, intralesionally (e.g. in oncology), topically or intravenously. (Tab. 2)

The good reasons for using Glucocorticoids (e.g. as anti-inflammatory, anti-pruritic or immuno- suppressive drug) cannot be separated from the many metabolic side effects.

CNS effects:
Euphoria and dysphoria, behaviour and mood modifications, polyphagia and polydipsia and seizure threshold can be lowered.

Gastrointestinal system:
Decreased absorption of calcium and iron salts, increased fat absorption, increased secretion of gastric acid, pepsin and trypsin, vomitus, diarrhoea, gastrointestinal ulcerations and pancreatitis.

Liver:
Increased glycogen deposits within hepatocytes, increased serum levels of liver enzymes like ALT and AST and also g-GT (Gamma Glutamyl Transpeptidase) can be increased. Severe increase of AP (alkaline Phosphatase) is frequently observed: In dogs the thermally stable AP-isoenzyme is induced by endogenous or therapeutically administered Glucocorticoids, but also by many other drugs. The increase can persist up to 2-4 weeks after termination of therapy. For clarification purpose the percentage of thermally stable AP can be determined at your lab. Increased values can be seen in 83-100% of dogs suffering from hyperadrenocorticism.

Musculoskeletal system:
Muscular weakness, atrophy, osteoporosis and weight increase (adrenocortical obesity).

Skin:
Skin atrophy und thinning of dermal tissue, calcinosis cutis, alopecia, formation of comedones, oedema and wound healing disorders

Hematopoietic system:
Involution of lymphatic tissue (species dependent), decreased amounts of lymphocytes (peripheral), monocytes and eosinophils, increased amounts of peripheral neutrophils, erythrocytes and circulating platelets (platelet aggregation is inhibited though), reduced blood coagulation time, inhibited phagocytosis, reduced prostaglandin, bradykinin, histamine and interleukin production.

Cardiovascular system:
Positive inotropic effect, reduced capillary permeability, enhanced vasoconstriction, arterial hypertension (retention of sodium chloride and water) and increased blood pressure (result from vaso-constrictive properties and increased blood volume).

Respiratory system:
Tachypnoe (panting).

Renal, fluid and electrolytes:
Increased reabsorption of water, sodium and chloride, increased excretion of potassium and calcium and therefore increased extracellular fluid volume. Also the effect of ADH is inhibited, thus resulting in polyuria.

Bones:
Inhibition of collagen synthesis carried out by fibroblasts, increased resorption of bone, decreased serum calcium level, vitamin D antagonist.

Endocrine system:
Suppression of the hypothalamus-pituitary gland-adrenal cortex axis, secondary hyperadrenocortisismus, secondary induced diabetes mellitus or a significant worsening of an already existing Diabetes mellitus.

Cells:
Stabilization of liposomal and lysosomal membranes, decreased macrophage reaction to migration inhibiting factor response, decreased lymphocyte and cellular response sensitivity to mediators of inflammation and inhibition of fibroblast proliferation.

Reproduction:
Teratogen in early pregnancy and when administered in the latter stages of pregnancy may induce parturition in equine and ruminant animals (less so in dogs and cats).

Ophthalmic system:
Prolonged use can cause increased intraocular pressure and glaucoma, cataracts and exophthalmos.

Adolescence/growth:
Growth inhibitor in young animals (CAVE: use of glucocorticoids in young and growing animals can retard their growth).

Immune system:
Decreased circulating levels of T-lymphocytes, inhibition of lymphokines, inhibition of neutrophils, macrophages and monocytes migration, reduced interferon production and inhibition of phagocytosis and chemotaxis. Glucocorticoids can also antagonize the complement cascade and mask clinical signs of infection with decreased number of mast cells, suppressed histamine synthesis and reduced amount of type 1 allergic effector cells in serum (basophils). Bottom line: immunosuppression and susceptibility to infection (e.g. infections of the urinary tract). (Tab. 3)

Glucocorticoids are pronounced antiinfl drugs, which can cause suppression of symptoms of acute, chronic, immunological or non-immunological infections. Very essential is the membrane stabilizing effect, which is extended to almost all biological membranes. Thereby inhibiting degranulation and releasing of inflamediators, causing a reduction in the capillary permeability and exsudative processes. Another mechanism affects the rapidly occurring inhibition of cyclooxygenase and thereby the synthesis of prostaglandins. Secondary, after a few hours, an additional blockade of the arachidonic acid cascade takes place. This early intervention in the arachidonic acid cascade not only results in the inhibition of the formation of prostaglandins but also of leucotriens. These play an important role in obstructive allergic respiratory diseases because of their vasoconstrictive effect on the bronchia. (Tab. 4)

Glucocorticoids and Allergy Testing

In cats suffering from allergic asthma a two-week withdrawal time from inhaled glucocorticoids is recommended prior to performing an intradermal skin test (IDST) (CHANG et al., 2011).
REEDY (1997) recommends a minimum of 6-8 weeks of withdrawal time after administration of injectable glucocorticoids. CLARKE et al. (2000) also found that dogs treated long term with corticoids and subsequently showed negative results on the ALLERCEPT® Fcε-receptor test, got positive test results after discontinuing of glucocorticoid therapy. Regarding orally given glucocorticoids and their influence on allergy testing KUNKLE (1994) showed that treatment of dogs with prednisone 1 mg/kg SID for 4-6 weeks made a significant reduction of reactions on the intradermal skin test (IDST). Another study showed that prednisolone and also cetirizine significantly influence and lower reactions in the IDST (TEMIZEL, 2011). Oral cortisone also reduces serum IgE levels considerably (SCHIESSL et al., 1998). Withdrawal times are also recommended for topical glucocorticoids and otic solutions containing cortisone. In a study 1% hydrocortisone containing conditioner (ResiCORT® Virbac) was applied once daily for 3 days. After treatment reduced IDST reactions were seen (RIVIERREL, 2000). Another study (BIZIKOVA, 2010) examined the influence of a locally used hydrocortisone aceponate spray (Cortavance® Virbac) on allergy testing. This spray reduced the IDST reactions and caused skin atrophy after long term treatment on all treated areas. Therefore, it is recommended to discontinue the applications for minimum 2 weeks prior to allergy testing.
Treatment with Otomax® (betamethasone containing otic solution) twice daily for 2 weeks reduced IDST reactions significantly in a study with 8 dogs (GINEL, 2007).
Although several withdrawal times regarding glucocorticoids, antihistamines and cyclosporine are discussed in different studies, our LABOKLIN Allergy Team recommends – based on our long clinical and laboratory experience – generally implementing the following withdrawal times prior to allergy testing: (Tab. 5)

Allergy is diagnosed according to clinical signs and accurate medical history, and the causative allergens are determined by allergy testing in order to either avoid them systematically or to perform an allergenspecific immunotherapy (ASIT). Thus, withdrawal times should be maintained to obtain the best possible test results and blood should be collected before any therapy with glucocorticoids is initiated, whenever possible.
Good quality serum can be stored in the refrigerator for a couple of weeks but frozen it can be stored for some months.
An allergy test which is performed during the glucocorticoid withdrawal time can be taken as valid, if it shows positive test results (reaction classes might have to be interpreted higher). In the case of negative test results, it is not possible to judge whether the result is truly negative or false negative because of the influence of glucocorticoids on allergy testing, and re-testing after withdrawal time is recommended.

Glucocorticoids and their Influence on Allergy Testing