Pathology Introduction

Pathology

Introduction

The word ‘Pathology’ is derived from two Greek words—pathos (meaning suffering) and logos (meaning study). Pathology is, thus, a scientific study of changes in the structure and function of the body in disease. In other words, pathology consists of the abnormalities in normal anatomy (including histology) and normal physiology owing to disease. Another commonly used term with reference to the study of diseases is ‘pathophysiology’ (patho=suffering, physiology=study of normal function). Pathophysiology, thus, includes the study of disordered function (i.e. physiological changes) and breakdown of homeostasis in

diseases (i.e. biochemical changes). Pathologists contribute inpatient management by providing the final diagnosis of disease. Therefore, knowledge and understanding of pathology are essential for all would-be doctors, as well as general medical practitioners and specialists because unless they have knowledge and understanding of the language in the form of pathology laboratory reports, they would not be able to institute appropriate treatment or suggest preventive measures to the patient.

COMMON TERMS IN PATHOLOGY

It is important for a beginner in pathology to be familiar with the language used in pathology:

”” The patient is the person affected by the disease.

”” Lesions are the characteristic changes in tissues and cells produced by disease in an individual or experimental animal.

”” Pathologic changes or morphology consist of examination of diseased tissues. These can be recognized with the naked eye (gross or macroscopic changes) or studied by microscopic examination of tissues.

EVOLUTION OF PATHOLOGY

Pathology as the scientific study of disease processes has its deep roots in medical history. Since the beginning of mankind, there has been a desire as well as a need to know more about the causes, mechanisms, and nature of diseases. The answers to these questions have evolved over the centuries—from supernatural beliefs to the present state of our knowledge of modern pathology. However, pathology is not separable from other multiple disciplines of medicine and owes its development to interaction and interdependence on advances in diverse neighboring branches of science, in addition to

the strides made in medical technology. As we shall see in the pages that follow, pathology has evolved over the years as a distinct discipline from anatomy, medicine, and surgery, in that sequence.

The following brief review of the fascinating history of pathology and its many magnificent personalities with their outstanding contribution in the form of a disease or a process known by

their names are meant to stimulate and generate interest in the inquisitive beginner in pathology as to how this colorful specialty has emerged.

 

BRANCHES OF PATHOLOGY

There are three main subtypes of pathology: anatomical pathology, clinical pathology, and molecular pathology.

Anatomical pathology:

Anatomical pathology is the study of anatomical features, such as tissue removed from the body, or even an entire body in the case of an autopsy, to diagnose and increase knowledge of the disease. Anatomical pathology can include looking at cells under a microscope, but it also involves looking at organs in general (e.g. a ruptured spleen). It also includes the investigation of the chemical properties of cells and their immunological markers. There are several broad subcategories of anatomical pathology:

• Surgical pathology is the examination of tissues removed during surgery. A common example is the examination of a small piece of tumor tissue to determine whether the tumor is malignant (cancerous) or benign and make a diagnosis. This procedure is called a biopsy.
• Histopathology is the examination of cells under a microscope that has been stained with dye to make them visible or easier to see. Often, antibodies are used to label different parts of the cells with different colors of dye or fluorescence. After the microscope became widespread in pathology, many different methods of preserving and dyeing tissue were developed.
• Cytopathology is the study of small groups of cells shed in bodily fluids or obtained through scraping, such as those taken during a cervical Pap smear. A Pap smear detects cervical cancer and some types of infections. The cells are taken by swabbing the cervix and are then processed and examined under a microscope to check for abnormalities.

• Clinical Pathology

  Clinical pathology diagnoses disease through laboratory analysis of bodily fluids and tissues. For example, the chemical components of Blood may be analyzed, along with analyzing cells and identifying any microorganisms such as bacteria that are present in a sample. Sometimes, the field of clinical pathology is also referred to as the field of laboratory medicine. Major types include the following:

  • Chemical pathology, or clinical chemistry, involves the chemical analysis of bodily fluids, through testing and microscopy. Commonly, chemical pathology involves the study of blood and its immune components like white blood cells.
  • Hematology is also related to the study of blood, but it has more to do with identifying blood diseases specifically than chemical pathology does. Hematologists also study the Lymph system and bone marrow, which are other parts of the hematopoietic system.
  • Immunology, or immunopathology, is the study of immune system disorders. It deals with immune responses to foreign molecules, allergies, immunodeficiencies, and organ transplant rejection.

  Molecular Pathology

  Molecular pathology is the study of abnormalities of tissues and cells at the molecular level. It is a broad category that is used to refer to the study of disease of any organ or tissue in the body by examining what molecules are present in cells. It can combine aspects of both anatomical and clinical pathology. Some techniques that can be used in molecular pathology include polymerase chain reaction (PCR) to amplify DNA, fluorescence labeling, karyotype imaging of chromosomes, and DNA microarrays (small samples of DNA placed onto biochips).

  Careers in Pathology

  Pathologists are medical doctors; to be a pathologist, one needs to go to school for a medical degree and complete residency. Only MDs can truly be described as pathologists. However, many different careers exist in the field of pathology, for those with various levels of education. With a high school degree and subsequent specialized training, one can become a phlebotomist, a person who draws blood from patients for training. With a two-year associate’s degree, one can become a laboratory technician. Laboratory technicians perform laboratory testing, often under supervision. A person with a bachelor’s degree, often in biology or Bio-chem, can become a research laboratory technologist or a clinical/medical laboratory technologist. In this position, one can assist in performing research and clinical testing. Those who go on to get a Master’s degree can become a laboratory manager or pathologist’s assistant. Those who go even further to get a Ph.D. can become a research laboratory scientist, where they will design experiments involving pathology in order to expand upon scientific knowledge and help doctors better treat disease.

  References

  • n.a. (2016-04-13). “Anatomic Pathology.” Lab Tests Online. Retrieved 2017-04-15 from https://labtestsonline.org/understanding/features/anatomic-pathology/.
  • n.a. (2017). “Careers in Pathology and Laboratory Medicine.” University of Rochester Medical Center. Retrieved 2017-04-15 from https://www.urmc.rochester.edu/pathology-labs/about-us/pathology-careers.aspx.
  • Mandal, Ananya. (2013-11-07). “Types of Pathology.” News-Medical.net. Retrieved 2017-04-15 from http://www.news-medical.net/health/Types-of-Pathology.aspx.
  • Netto, George. J., Saad, Rana D., and Dysert, Peter A., II. (2003). “Diagnostic molecular pathology: current techniques and clinical applications, part I.” Proc. (Bayl. Univ. Med. Cent.) 16(4): 379–383.
  • “Pathology.” Merriam-Webster.com. Retrieved 2017-04-14 from https://www.merriam-webster.com/dictionary/pathology.
  • Van den Tweel, Jan G., and Taylor, Clive R. (2010). “A brief history of pathology.” Virchows Arch. 457(1): 3–10.