Microanatomy in Clinical Practice

Microanatomy In Clinical Practice

• Author: Matthew J Valentine, BVMS, PhD, MRCVS, Dipl. ACVP

• Content adapted from Allan Kessell

Understanding Disease

• Definition of disease: "a departure from health due to abnormality of structure or function."

• Diagnosis requires knowledge of normal structures and functions to differentiate from abnormalities.

Diagnosis Process

• Components of diagnosis:

  • Signalment: Identification and basic information about the patient (species, breed, age, sex).

  • History: Gathering information on previous medical history and presenting complaints.

  • Physical examination: Comprehensive assessment of the patient’s physical condition.

  • Ancillary tests: Additional tests to provide further information, categorized into:

    • Diagnostic imaging: Techniques like X-rays, ultrasounds to visualize internal structures.

    • Laboratory investigations: Analyzing biological samples for disease indicators.

  • Ancillary tests extend beyond basic diagnosis and often involve microscopic examination of cells, tissues, and fluids.

Clinical Pathology and Its Applications

• Clinical Pathology: Testing blood, urine, feces, milk, lumps, etc.

• Anatomic Pathology: Examining tissues from biopsies and necropsies to see structural changes (lesions).

• Microbiology: Investigating infectious causes including bacteriology, virology, mycology, and parasitology.

Antemortem Sampling Techniques

• Types of samples:

  • Blood: Blood cells, plasma, serum, bone marrow.

  • Urine: Analysis of kidney function.

  • Milk and feces: Evaluating health in livestock.

  • Body fluids: Such as pleural, peritoneal, pericardial fluids, semen, CSF, joint fluid.

  • Washes: Tracheal and bronchial washes.

  • Tissue samples: Aspirates, impressions, scrapings, brushes, and biopsies.

Hematological Analysis

• Erythrogram Results:

  • Normal ranges:

    • RBC count: 5.5 – 8.5 x 10²/l

    • Hemoglobin: 120-180 g/l

    • PCV: 37 – 55%

    • MCV: 60-77 fl

    • MCH: 19 – 24 pg

    • MCHC: 320 - 360 g/l

    • Reticulocytes, leukograms and platelet counts included for further assessment.

Biochemistry Analysis

• Normal Results Ranges:

  • Sodium: 138-153 mmol/l

  • Potassium: 3.9 – 5.7 mmol/l

  • Chloride: 101 – 114 mmol/l

  • Calcium: 1.9 – 2.9 mmol/l

  • Bicarbonate: 15 – 24 mmol/l

  • Urea: 2.5 – 9.5 mmol/l

  • Creatinine: 44 – 150 µmol/l

  • Various other electrolytes, total protein measures, and enzyme levels indicating organ function.

Understanding Urinalysis

• Urinalysis includes gross observation and different measurements:

  • Address specific gravity, protein content, among other indicators.

Cytology

• Cytology Examination: Sampling techniques to assess cells from surfaces, lumens, or organ solid portions.

• Involves evaluation of stains from cytological samples.

Histopathology Techniques

• Biopsy Procedure: Sample collection from living animals using 10% buffered formalin.

• Importance of tissue preservation through fixation and embedding techniques.

Gross and Microscopic Anatomy

• Comparison of gross anatomy versus microscopic anatomy, evaluating diseases through imaging and structural examination using staining methods.

Case Studies

• Case study: 18-year-old brood mare shows signs of colic and depression,

  • Diagnostic methods used: clinical history and physical examination revealed weight loss, elevated heart rate, and abnormal gastrointestinal sounds.

• Recommended examinations and potential diagnosis strategies explored through analysis of signs of discomfort and physical state.

Imaging and Further Diagnosis

• Use of ultrasound to evaluate anatomical structures and assess abdominal fluid presence, critical for determining progression or resolution of clinical signs.