Pharyngitis: Nursing

Pharyngitis, more commonly known as sore throat, is an inflammatory disease of the pharynx, or the back of the throat, and it’s most often caused by an invading pathogen like a virus or bacteria, and rarely by fungi.

Now, let’s quickly review a bit of anatomy and physiology of the respiratory tract. When we breathe in, air enters the respiratory tract through the nose or mouth, respectively into the nasal and oral cavities, and then into the pharynx. At each side of the back of the throat, there is a pair of structures called adenoids and tonsils, which are small clumps of lymphoid tissue that act as the body's first line of defense that swallow harmful foreign particles and pathogens that enter through the nose or mouth. The lower part of the pharynx is continuous with the larynx or the voice box. Now, the pharynx also connects the oral cavity to the esophagus. So, at the top of the larynx sits a spoon-shaped flap of cartilage called the epiglottis, which acts like a lid that seals the airway off while eating or drinking, so that anything we consume can only go one way, down the esophagus and towards the stomach. In contrast, during breathing, the epiglottis stays open, so that air can make its way into the larynx, and then continue its journey through the trachea, or windpipe, towards the lungs.

Zooming in, the epithelium lining respiratory tract consists of goblet cells that release mucus, which is sticky and contains enzymes to help trap and destroy harmful foreign particles and pathogens; as well as columnar epithelial cells that have hair-like projections called cilia, which work to sweep the harmful particles up and out of the airways. In addition, the epithelial layer that lines the pharynx is actually thicker than elsewhere in the respiratory tract, as it has to protect the tissues from any harmful particles from the air we breathe in, as well as from anything we consume.

Okay, so pharyngitis is caused by any harmful particle that manages to breach these defense mechanisms and irritates the epithelial layer that covers the pharynx. In most cases, the cause is infectious. Typically, the pathogen is transmitted from person to person via respiratory droplets or aerosolized particles expelled from an infected individual when talking, coughing, or sneezing. Most often, these droplets land in the eyes, nose, or mouths of people nearby, infecting them; less frequently, the pathogen is transmitted indirectly when an individual touches a contaminated surface and then, prior to washing their hands, they touch their eyes, nose, or mouth.