Sunday, March 14, 2021

Recurrent Tonsillitis Case File

Posted By: Medical Group - 3/14/2021 Post Author : Medical Group Post Date : Sunday, March 14, 2021 Post Time : 3/14/2021
Recurrent Tonsillitis Case File
Eugene C. Toy, MD, Lawrence M. Ross, MD, PhD, Han Zhang, MD, Cristo Papasakelariou, MD, FACOG

CASE 49
A 7-year-old boy was referred to an ear-nose-throat (ENT) specialist after experiencing recurrent episodes of tonsillitis with peritonsillar abscesses. His mother noted about seven infections over the past 8 months, all treated with antibiotics. After discussing treatment options with the family, the ENT specialist recommended a tonsillectomy. The patient’s tonsillectomy was complicated by bleeding from the surgical bed, and he had temporary loss of taste sensation from his posterior tongue. He is currently doing well and without complaints.

 The intraoperative bleeding was most likely from which blood vessel?
 Why was there a temporary loss of taste sensation?


ANSWER TO CASE 49:

Recurrent Tonsillitis
Summary: A 7-year-old boy is status posttonsillectomy for recurrent tonsillitis complicated
by increased intraoperative bleeding and temporary loss of taste sensation
from the posterior one-third of the tongue.

• Vessel involved with intraoperative bleeding: External palatine vein

• Loss of taste sensation: Compression of glossopharyngeal nerve (CN IX)


CLINICAL CORRELATION
For patients with recurrent episodes of tonsillitis or peritonsillar abscesses (>4 episodes per year), tonsillectomy may be indicated. Although tonsillectomy is regarded as a routine procedure, it is not without complications and risks. A thorough understanding of the anatomy of the pharynx is necessary in order to limit complications. The tonsillar bed is extremely vascular with the most common source of intraoperative bleeding from the external palatine vein, which arises from the lateral aspect of the tonsillar bed. Even if a direct injury does not occur, compression from edema may cause temporary injury as in this case. Compression of glossopharyngeal nerve branches causes a temporary loss in taste sensation on the posterior aspect of the tongue. As the swelling decreases, so does the nerve impairment. Many other vital vessels, nerves, and structures are adjacent to the tonsils, and care must be taken to avoid injury.


APPROACH TO:
The Tonsils

OBJECTIVES
1. Be able to describe the divisions of the pharynx
2. Be able to list the muscles that form the pharynx
3. Be able to describe the components of the tonsillar ring
4. Be able to identify vessels that supply the pharynx, especially branches that course through the tonsillar beds
5. Be able to identify the cranial nerves providing sensory and motor innervation to the pharynx


DISCUSSION
The pharynx is a space within the head that connects the oral and nasal cavities to the trachea and esophagus. Air-filled spaces in the temporal bone (i.e., the tympanic cavity and the mastoid air cells) connect with the pharynx through the pharyngotympanic (eustachian) tube. The walls of the pharynx are covered with mucosa. Deep to the mucosa are several aggregations of lymphoid tissue that form a ring around the pharynx, priming the immune system for defense against pathogens (see Figure 49-1).

The superior boundary of the pharynx is the base of the skull. The muscles of the pharyngeal walls form a cone that narrows to the esophagus. The medial pterygoid plates support the lateral walls of the superior part of the pharynx. The bodies of cervical vertebrae support the posterior wall. The anterior wall is interrupted by three apertures. One opens to the nasal cavity, another to the oral cavity, and a third to the larynx. Therefore, the pharynx is divided into three corresponding regions: the nasopharynx, the oropharynx, and the laryngopharynx. The naso- and oropharynx are continuous but are separated by elevation of the soft palate during swallowing to prevent reflux of food and liquid into the nasopharynx. The oro- and laryngopharynx are also continuous. Depression of the epiglottis during swallowing separates the larynx from the laryngopharynx, preventing aspiration into the trachea and lungs.

Recurrent Tonsillitis anatomy

Figure 49-1. Median section through pharynx.

The pharyngeal wall is composed of three muscles: the superior, middle, and inferior pharyngeal constrictors. The inferior part of the inferior constrictor muscle thickens as it merges with the esophagus, forming a sphincter called the cricopharyngeus muscle. The three constrictor muscles are stacked like ice cream cones. Between the pairs of muscles are gaps that transmit important structures. The gap between the superior constrictor and the occipital bone transmits the pharyngotympanic tube, the levator veli palatini muscle, and the ascending palatine artery. Between the superior and middle constrictors are the glossopharyngeal nerve and stylopharyngeus muscle. Between the middle and inferior constrictors course the internal laryngeal nerve and the superior laryngeal artery. The recurrent laryngeal nerve and the inferior laryngeal artery ascend deep to the inferior constrictor.

The lymphoid tissue surrounding the pharynx is commonly called the Waldeyer ring, which is composed of three masses of lymphoid tissue: the pharyngeal tonsils (also called “adenoids” when enlarged), the palatine tonsils, and the lingual tonsils. The pharyngeal tonsils are located in the roof and posterior wall of the nasopharynx. The opening of the pharyngotympanic tube into the nasopharynx is protected by a tonsil. The palatine tonsils are located in the anterior wall of the oropharynx between the palatoglossal and palatopharyngeal folds. The lingual tonsil is located under the mucosa of the posterior one-third of the tongue.

The pharynx is supplied by arteries from several sources, most of which are branches of the external carotid artery, specifically the maxillary, facial, lingual, and superior thyroid arteries. The constrictor muscles are also supplied by branches from the deep cervical and inferior thyroid arteries. With respect to this case, the most important vessels are the ascending palatine and tonsillar branches of the facial artery. Surgery to remove the palatine tonsil can damage the tonsillar branch, resulting in excessive bleeding. Venous drainage from the pharynx parallels the arterial supply. In addition, there is an extensive pharyngeal venous plexus on the posterior surface of the constrictor muscles. The external palatine vein descends along the lateral surface of the palatine tonsil to drain into the venous plexus. Therefore, this vessel may be damaged during surgery to remove a palatine tonsil, also resulting in excessive bleeding.

The nerve supply to the pharynx is from cranial nerves IX and X. The glossopharyngeal nerve (CN IX) supplies general sensory fibers to the mucosa of the pharynx. These fibers contribute to the afferent limb of the gag reflex. CN IX also supplies special sensory fibers mediating taste to the posterior one-third of the tongue. This nerve exits the cranium through the jugular foramen and descends with the stylopharyngeus muscle to pass through the gap between the superior and middle pharyngeal constrictor muscles. The vagus nerve (CN X) supplies general motor fibers to the constrictor muscles. These fibers contribute to the efferent limb of the gag reflex. This nerve also exits the cranium through the jugular foramen but descends within the carotid sheath. As it descends, it gives off branches that form the pharyngeal plexus on the posterior surface of the pharynx. In this case, edema from the tonsillectomy compressed the branches of CN IX, blocking the sensation of taste from the posterior one-third of the tongue.


COMPREHENSION QUESTIONS

49.1 During a procedure to remove a palatine tonsil, the operating field was suddenly filled with bright red blood. Which artery was inadvertently damaged?
    A. Tonsillar branch of facial
    B. Ascending pharyngeal
    C. Ascending palatine
    D. Descending palatine
    E. Lingual

49.2 A patient has a mild chronic cough but has clear lungs and no evidence of bronchitis. Her physician believes that the symptoms are due to postnasal drip brought on by allergy. Which nerve is responsible for the afferent limb of the cough reflex?
    A. CN V2
    B. CN V3
    C. CN VII
    D. CN IX
    E. CN X

49.3 Which structure passes through the gap between the superior and middle constrictor muscles?
    A. Recurrent laryngeal artery
    B. Internal laryngeal nerve
    C. Superior laryngeal artery
    D. Glossopharyngeal nerve
    E. Pharyngotympanic tube


ANSWERS
49.1 A. The tonsillar branch of the facial artery lies in the bed of the palatine tonsil and is susceptible to injury. Although the ascending palatine artery sends branches to the tonsil, it is unlikely to be affected in a routine procedure.

49.2 D. The cough reflex is stimulated by irritation of the laryngopharynx, which is innervated by CN IX. The trigeminal nerve (CN V1 and V2) innervates the oral and nasal cavities.

49.3 D. The glossopharyngeal nerve (CN IX) passes through the gap between the superior and middle constrictors, along with the stylopharyngeus muscle and stylohyoid ligament.


ANATOMY PEARLS
 The three pharyngeal constrictor muscles are stacked like ice cream cones. Structures pass into the pharynx through gaps between the muscles.
 The tonsillar (Waldeyer) ring is a discontinuous mass of lymphoid tissue located where the body opens to the environment, exposing the immune system to pathogens.
 At the base of the palatine tonsil, the tonsillar branch of the facial artery and the glossopharyngeal nerve (CN IX) can be identified.
 The gag reflex is evoked by mechanical stimulation of the oropharynx. The afferent limb of the reflex is mediated by the glossopharyngeal nerve (CN IX), and the efferent limb is mediated by the vagus nerve (CN X).

References

Gilroy AM, MacPherson BR, Ross LM. Atlas of Anatomy, 2nd ed. New York, NY: Thieme Medical Publishers; 2012:582−583, 586−587. 

Moore KL, Dalley AF, Agur AMR. Clinically Oriented Anatomy, 7th ed. Baltimore, MD: Lippincott Williams & Wilkins; 2014:1032−1036, 1047−1048. 

Netter FH. Atlas of Human Anatomy, 6th ed. Philadelphia, PA: Saunders; 2014: plates 64, 68.

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