Sunday, March 14, 2021

Dental Abscess/Ludwig Angina Case File

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

CASE 52
A 45-year-old woman complains of a left posterior toothache for the past 2 weeks that she treated with saltwater gargles. However, over the past 24 h, she has had fever and difficulty opening her mouth while talking or swallowing. On examination, the patient has a fever of 101°F, with redness of the left submandibular region extending to the left side of her throat. She is sitting up but is anxious and drooling and has some inspiratory stridor. The physician states that the infection in the mouth has spread to the neck and may ultimately enter the chest.

 What is the most likely diagnosis?
 What is the anatomical mechanism for this condition?


ANSWER TO CASE 52:

Dental Abscess/Ludwig Angina
Summary: A 45-year-old woman had a left molar toothache for 2 weeks but now has fever, trismus, and dysphagia. There is a left submandibular inflammation extending to the left side of the throat. She is sitting but is anxious and drooling and has some inspiratory stridor. This infection may track from the mouth to the neck to the chest.

• Most likely diagnosis: Submandibular cellulitis (Ludwig angina)

• Anatomical mechanism for this condition: A dental (molar) abscess that has tracked inferiorly from the submandibular space to impinge on the trachea


CLINICAL CORRELATION
Dental abscesses are relatively common occurrences and typically are self-limited or easily treated with antibiotics such as penicillin. Occasionally, an infection involving the molar teeth may extend into the submandibular space (Ludwig angina) and affect the trachea or carotid sheath contents. Fever, painful edema, limited neck mobility, drooling, and difficulty opening the mouth are clinical findings. The infection can also extend inferiorly into the mediastinum (mediastinitis). The inspiratory stridor in this case may indicate tracheal compression. In such cases, laryngoscopy may lead to laryngospasm and complete airway obstruction. Lateral neck radiographs or CT imaging are helpful in the diagnosis. The best treatment is intravenous antibiotics, airway protection (intubation if needed), and operative drainage of the abscess.


APPROACH TO:
The Oral Cavity

OBJECTIVES
1. Be able to list the layers of the deep cervical fascia
2. Be able to describe the structures in the floor of the mouth and submandibular space and its communications with the spaces of the neck
3. Be able to describe the route of spread of infection from the oral cavity into the thorax

DEFINITIONS
STRIDOR: A high-pitched whispering sound with respiration that indicates obstruction of the airway

TRISMUS: Sustained contraction of the masseter muscle, leading to “lockjaw”

DYSPHAGIA: Difficulty or pain with swallowing

LIGAMENTUM NUCHAE: A thickened extension of the supraspinal ligament into the neck.


DISCUSSION
The deep cervical fascia consists of connective tissue sheets that enclose and support various structures in the neck. Deep to the superficial fascia and platysma, the investing fascia (the superficial layer of deep fascia) encircles the neck and splits to enclose the SCM and the trapezius muscles and attaches to the ligamentum nuchae posteriorly. Superiorly, it attaches to the hyoid bone, mandible, and base of the skull; inferiorly, it attaches to the acromion, clavicle, and manubrium of the sternum. The prevertebral fascia surrounds the cervical vertebral column, the spinal cord, and the pre- and paravertebral musculatures. It attaches to the base of the skull superiorly and the ligamentum nuchae posteriorly, and blends with the anterior longitudinal ligament of the vertebral column in the thorax. The pretracheal fascia surrounds the larynx, trachea, esophagus, thyroid, and parathyroid glands and splits to enclose the infrahyoid (strap) muscles of the neck. It is attached superiorly to the hyoid bone and inferiorly blends with the fibrous pericardium in the thorax. Posteriorly and superiorly, it is continuous with the buccopharyngeal fascia. The carotid sheath is usually described as having originated in the investing, prevertebral, and pretracheal layers.

Between the prevertebral and buccopharyngeal fasciae lies the retropharyngeal space (“danger space”). This space is a pathway for spread of infection to the thorax, possibly resulting in cardiac tamponade. Within the pretracheal fascia is a potential space filled with loose areolar connective tissue called the visceral space (Figure 52-1).

The submandibular space lies between the mucosa of the floor of the mouth and the mylohyoid and hyoglossus muscles. The root of the tongue lies medially, and the inner surface of the mandible lies laterally. The space contains the sublingual gland and ducts, a portion of the submandibular gland and its duct, and the lingual and hypoglossal nerves. A cleft exists between the mylohyoid and hyoglossus muscles, through which the submandibular gland wraps around the posterior border of the mylohyoid muscle. The roots of the posterior molar teeth are close to the inner surface of the mandible, thus increasing the risk for dental abscesses spreading into the submandibular space. Infectious material can thus spread inferiorly into the visceral space through the cleft between the mylohyoid and hyoglossus muscles.

Compartments of the neck

Figure 52-1. Compartments of the neck: 1 = investing fascia, 2 = sternocleidomastoid muscle, 3 = infrahyoid muscle, 4 = trapezius muscle, 5 = visceral (pretracheal) fascia, 6 = thyroid gland, 7 = trachea, 8 = recurrent laryngeal nerve, 9 = esophagus, 10 = buccopharyngeal fascia, 11 = alar fascia (present only in upper pharynx), 12 = retropharyngeal (retroesophageal) space, 13 = neurovascular (carotid) sheath, 14 = common carotid artery, 15 = internal jugular vein, 16 = vagus nerve, 17 = prevertebral fascia, 18 = phrenic nerve, 19 = sympathetic trunk, 20 = roots of the brachial plexus, 21 = vertebral artery. (Reproduced, with permission, from the University of Texas Health Science Center, Houston Medical School.)


COMPREHENSION QUESTIONS

52.1 A 67-year-old man developed a dental abscess that he ignored for 2 weeks. At that time, he developed severe chest pain due to infection of the mediastinum. Through which pathway did the infection most likely spread to the mediastinum?
    A. Masticator space
    B. Pretracheal space
    C. Retropharyngeal space
    D. Suprasternal space

52.2 A dentist uses local anesthesia to prepare for a procedure on a lower molar tooth. Which of the following nerves is the dentist blocking?
    A. Submental
    B. Maxillary
    C. Mandibular
    D. Vagus

52.3 A 24-year-old male was involved in a knife fight in a bar. He appeared in the emergency department with a 2-cm laceration in the anterolateral neck. The wound was superficial, but the physician observed muscle fibers just deep to the superficial fascia. Which of the following muscles was observed?
    A. Platysma
    B. Sternocleidomastoid
    C. Omohyoid
    D. Trapezius
    E. Thyrohyoid


ANSWERS
52.1 C. The major pathway between the infections of the neck and the chest is through the retropharyngeal space, which is a potential space between the prevertebral layer of fascia and the buccopharyngeal fascia surrounding the pharynx.

52.2 C. Dental anesthesia involving the lower molar teeth is called a lower mandibular block. The nerve affected is the inferior alveolar nerve branch of the mandibular nerve, which is a branch of V3.

52.3 A. The platysma muscle is a wide flat muscle that covers the anterolateral region of the neck.


ANATOMY PEARLS
 The submandibular space is continuous with the visceral space in the neck.
 The investing, pretracheal, and prevertebral deep cervical fasciae contribute to the carotid sheath.
 The major pathway for infection between the neck and the chest is the retropharyngeal space.

References

Gilroy AM, MacPherson BR, Ross LM. Atlas of Anatomy, 2nd ed. New York, NY: Thieme Medical Publishers; 2012:530−531, 576, 606−609. 

Moore KL, Dalley AF, Agur AMR. Clinically Oriented Anatomy, 7th ed. Baltimore, MD: Lippincott Williams & Wilkins; 2014:985−989. 

Netter FH. Atlas of Human Anatomy, 6th ed. Philadelphia, PA: Saunders; 2014: plates 26, 67, 75.

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