Diagnostic Techniques

Transcription

1 Diagnostic Techniques LAT Chapter 10 LATG Chapter 14 Laura Gallaugher, DVM

2 Diagnosisi Why do we need healthy animals? Clinical and subclincal disease affects lifespan, growth rates, breeding, tumor growth, immunology, etc Experimental consistency, variability and validity Reduction! Zoonoses

3 Diagnosisi Determining the nature of the disease Tests Results compared to normal values Data + history + clinical i l signs = diagnosisi Prognosis: forecast of the probable course and outcome of the disease

4 Topics Parasitology Ecto-& Endo-parasites Hematology CBC, Biochemical Profiles, Serology Pathology Necropsy Radiology X-ray, CT, MRI, PET, PET-CT, Ultrasound, IVIS & Faxitron

5 Parasitology Study of organisms: that live on (ectoparasites) or that t live in (endoparasites) another organism Draw nourishment from their host

6 Parasitology Endoparasites Adults found in GI tract Et Ectoparasites Bite host & ingest body fluids Observe appearance & behavior Hair loss, Skin lesions, ITCHING!

7 Endoparasite Detection ti Direct smear: Protozoan (motile) Fecal Flotation: parasite eggs Tape Test: pinworm eggs (Syphacia) Syphacia obvelata Aspiculuris tetraptera

8 Endoparasite Detection ti Gross Examination: Tape Gross Examination: Tape segments (grains of rice)

9 Ectoparasites Skin Scraping: mites Tape Test: fur mites in mice

10 Ectoparasites Myocoptes musculinus Myobia musculi Radfordia affinis

11 Hematology Study of the production, use and destruction of blood components One of the most useful diagnostic tests Infections, dehydration, anemia

12 Complete Blood Count (CBC) Evaluates the number & types of cells in the blood Red Blood Cell Count & volume Hemoglobin concentration White blood cell count Platelet count

13 Blood Smear Shape and appearance (morphology) of blood cells WBC differential (types & amounts) Determines the % of each type of WBC Can be done with an automated hematology analyzer

14 Red Blood Cell Count Million of cells/microliter of blood Low RBC count = anemia High RBC count = dehydration

15 Hematocrit or PCV The percentage of the blood volume occupied by blood cells (packed cell volume)

16 Hematocrit or PCV Color of plasma: Yellow: icterus (jaundice) Red: cell lysis Cloudy: hyperlipidemia (Fatty meal)! Buffy coat: Thicker: high h WBC count

17 WBC Differential Neutrophils/Heterophils Segmented nuclei & cytoplasmic granules Elevations = infection, inflammation

18 WBC Differential Band Neutrophils Immature, unsegmented neutrophils Increased: Bacterial infection

19 WBC Differential Lymphocytes Round, smooth-surfaced Increases: acute infection, leukemia Decreases: Stress

20 WBC Differential Eosinophils Red-staining granules in cytoplasm Increases: allergic Increases: allergic reaction, parasites

21 WBC Differential Basophil Bluish-staining granules Monocyte Large leukocyte w/ bean-shaped nucleus

22 Peripheral Blood Smear Examine red & white cell morphology Prepared from anticoagulated blood within 15 minutes of collection Stain within 1 hour

23 Platelet l t Count Source of clotting factors Maintain integrity of blood vessels <50, ,000/ul can lead to bleeding

24 Serum Chemistries i What is serum? The liquid that remains after blood has been allowed to clot What is plasma? The liquid (non-cellular) portion of the unclotted blood Contains clotting proteins!

25 Serum Chemistries i Study of changes in the concentrations of biochemical substances in the blood Enzymes ALT alanine transaminase Metabolic waste products BUN blood urea nitrogen Electrolytes l t sodium, potassium, calcium, chloride

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27 Serum Chemistries i Tell us: Which organ or system is affected BUN & creatinine i = kidney ALT & Bilirubin = Liver Lipase & Amylase = Pancreas How severely

28 Serology Study of serum with respect to the presence or absence of antibodies Antibodies are secreted in response to an antigen Specific Indicate exposure has occurred

29 Serology Titer Dilute serum into series of decreasing concentrations & test the solution for antibody reactivity Most dilute solution that is positive The higher the titer, the more antibody present Tells you timing of infection

30 Serology Mainstay of viral surveillance Viral antibodies can be detected for a prolonged time One serum sample can be tested for antibodies for a panel of viruses ELISA (Enzyme-linked Immunosorbent Assay)

31 Ui Urinalysis i Study of the physical & chemical properties of urine General observations: Color Odor Turbidity

32 Ui Urinalysis i Chemical Determinations dipsticks Glucose Protein Blood ph

33 Ui Urinalysis i Specific Gravity Indicates kidney s ability to concentrate urine Compared with plasma Urine is a solution Specific gravity >

34 Ui Urinalysis i Hematuria: blood in the urine Hemoglobinuria: excretion of hemoglobin into the urine from breakdown (hemolysis) of RBC Myoglobinuria: excretion of myoglobin into urine from traumatic ti muscle injury Positive for blood on dipstick

35 Ui Urinalysis i Sediment Analysis: Centrifuge & Stain Crystals Epithelial cells RBC & WBC

36 Microbiology Study of microorganisms Isolating & identifying bacteria, fungi Sterile specimen collection is paramount

37 Microbiology

38 Minimum Inhibitory Concentration The lowest concentration of an antimicrobial (antibiotic) that will inhibit the visible growth of a microorganism after overnight incubation Antibiotic Sensitivity

39 Necropsy Can help determine the cause of death Case History Perform necropsy as soon as possible! Don t Freeze the carcass!

40 Necropsy Be consistent External features Gender, BW, skin, general condition i Describe & record any lesion Location, size, amount, color, number & distribution

41 Radiography Diagnostic imaging g by means of controlled radiation X-rays: electromagnetic waves Short wavelength Expose photographic film Cause changes in living cells, genes & chromosomes

42 Radiography radiolucent radiopaque

43 Faxitron What Faxitron does: Cabinet X-ray system for specimen radiography and research High contrast, high resolution imaging jgl/jgl mouse with fusions of tail vertebrae and exostoses of vertebrae

44 Fluoroscopy Takes moving pictures Used for angiography Follow the path of the catheter instantaneously Increased radiation exposure e

45 Ultrasound Uses sound waves Bounced into the body, reflections are transformed into an image Image is opposite to radiographs Portable Internal & external Real-time moving pictures

46 Magnetic Resonance Imaging How MRI works H2O Magnetic field aligns water protons Proton positions are determined by applying additional magnetic fields during the scan Different tissue type protons return to equilibrium state at different rates 9.4T MRI

47 Magnetic Resonance Imaging Indications MRI is used to image every part of the body Particularly useful for (non-boney): Neurological conditions, brain and spinal cord Disorders of the muscles and joints For evaluating tumors Showing abnormalities in the heart and blood vessels.

48 Magnetic Resonance Imaging Whole body mouse MRI

49 Computed Tomography How CT works Series of 2-dimensional X-ray images taken around a single axis of rotation Digital geometry processing generates a threedimensional image of the object

50 Positron Emission Tomography (PET) Radiation emitted by a radioisotope is measured to create the image Visualizes biological processes in vivo Blood flow Metabolism

51 PET-CT How PET-CT works: Combines positron emission tomography with an x-ray computed tomography Functional imaging: PET Anatomic imaging: CT

52 PET-CT

53 In vivo Imaging Systems What IVIS does: Evaluates biological processes (i.e. molecular pathways) within intact, living organisms Non-invasive gene expression determination Bioluminescent or fluorescence

54 You be the VET

55 Diagnostic Case 1 year old, Male, C57BL/6 Mouse Itching constantly Hairloss around neck, ears and shoulders Diagnostic Test? Tape Test/Fur Pluck to check for furmites

56 Diagnostic Case 2 year old, female, NZW Rabbit Not eating Scant feces QAR Diagnostic Test? Check teeth palpate abdomen Bloodwork Check teeth, palpate abdomen, Bloodwork Radiograph

57 Diagnostic Test 3 year old, Female, Beagle Urinating frequently, straining to urinate, urine is discolored d Diagnostic Test? Urinalysis, culture, antibiotic sensitivity

58 Quiz If there is a delay before an animal can be necropsied, what is the best approach to preserve the body? A. Keep it refrigerated to prevent rapid decomposition B. Put it in the freezer to prevent decomposition i C. Keep it at room temperature but protect it from insects and other animals D. The animal should always be necropsied within 8 hours of its death

59 Quiz Which term means "to predict the outcome of a disease?" A. Prognosis B. Diagnosis C. Therapeutic index D. Treatment

60 Quiz Which of the following best describes plasma? A. The liquid portion of clotted blood B. Whole blood C. The liquid id portion of unclotted blood D. Unclotted blood

61 Quiz What instrument best aids placement of a catheter into a heart? A. Fluoroscope B. Radiograph C. CT scanner D. Sonogram

62 Quiz What type of tissue allows the least absorption of x-rays? A. Bone B. Lungs C. Muscle D. Blood

63 Quiz What clinical chemistry test measures kidney function? A. BUN B. Blood glucose C. CPK D. ALT

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