Clinical Cases - Upper GI Tract

An eight year-old boy presents to his physician with a chief complaint of an earache, fever and some degree of hearing loss. The patient's case history indicates a recent viral upper respiratory tract infection. During physical exam, the physician examines the patient with an otoscope and notes an inflamed tympanic membrane that is bulging and opacified. Pneumatic otoscopy confirms the presence of fluid in the middle ear. The patient is diagnosed with acute otitis media, an infection of the mucoperiosteal lining of the middle ear which has a relatively sudden onset and short duration.

Questions to consider:

1. A major factor in the pathogenesis of otitis media is dysfunction of the auditory (Eustachian) tubes. What is the function of the auditory tubes?

   The normal function of the auditory (old term: eustachian) tubes is to regulate pressure within the middle ear (ventilation), protect the middle ear by preventing nasopharyngeal aspiration (protection), and allow clearance of secretions from the middle ear (drainage).

2. If the ventilatory function of the auditory (eustachian) tubes is compromised, air is resorbed by the middle ear and a negative pressure, anaerobic environment is created in the middle ear. The negative pressure may result in aspiration of nasopharyngeal contents, including bacteria, into the middle ear that then proliferate to cause otitis media. Which muscle opens the auditory (Eustachian) tube?

   The tensor veli palatini muscle opens the auditory tube during swallowing by pulling on the cartilage of its lateral wall.

3. What surgical procedures may be used to treat the fluid build-up in the middle ear?

   Surgical alleviation of fluid build-up includes myringotomy. This procedure involves making a curvilinear incision in the inferior portion of the tympanic membrane below the malleus handle. The incision should be long enough to allow good drainage, the fluid may be gently suctioned. Post-operationally, cotton should be inserted into the patient's ear to absorb the drainage.
   
   In the case of the patient with recurrent or chronic (fluid build-up lasting for more than 2 or 3 months) otitis media, the patient may have a tympanostomy tube inserted. In the long-run, the tube equalizes middle ear pressure by preventing the early closure of the initial myringotomy opening thus artificially maintaining proper middle ear ventilation.

4. What are possible complications to otitis media?

   Possible intratemporal complications due to otitis media include mastoiditis, an invasive infection of the mastoid air cells which is frequently accompanied by abscess formation and invasion into surrounding bone. It is generally associated with otitis media.
   
   Possible intracranial complications to otitis media include brain abscess, extradural abscess, subdural abscess, and meningitis.

5. What would an infection of the outer ear be called? What anatomical features/structures protect the ear from injury?

   An infection of the outer ear is called otitis externa. Features and structures that protect the ear include: a small opening to the auditory canal, the narrow isthmus and upward orientation of the auditory canal, hair in the auditory canal, and the presence of sebaceous and apocrine glands that produce the water-repellent cerumen (ear wax).

A 5-year-old girl was taken to the primary health care physician because she was having sore throat, high temperature and runny nose. Symptoms started a couple of days ago and her mother reported that she also complained of pain in the right ear at night. The doctor examined her tonsils and found them enlarged, and checked her ears with the otoscope and saw that both eardrums were congested and looked reddish especially on the right. He recommended decongestant medication and analgesics and requested to see the girl again a week later.

Questions to consider:

1. How would you explain the congestion of both eardrums?
   

   The auditory (Eustachian) tube provides a passage for organisms to reach the middle ear from the nasal cavity. In children the tube is more horizontal and shorter than in adults, and therefore the possibility of spread is higher. One of the earliest signs of otitis media is congestion of the eardrum that may be seen easily with otoscope.

2. If the ear infection was not treated properly, what important anatomical structures are likely to be affected in the middle ear?
   

   Neglected otitis media may lead to rupture of the tympanic membrane and loss of hearing. Ossicles may be involved, and that may lead to further deterioration of hearing. Infection may spread posteriorly to the mastoid air cells causing mastoiditis, with possible spread to the posterior cranial fossa and infection of meninges.

A 14 year old male was brought to the emergency room by his mother. Symptoms of severe headache, photophobia, nausea, vomiting, fever of 103, and nuchal rigidity (resistance to flexion of the neck) began the evening before, and progressed rapidly during the night. Suspecting meningitis, a lumbar puncture was performed. The CSF appeared purulent and turbid.

CSF lab analysis showed increased protein levels, decreased sugar, and many polymorphonuclear leukocytes. This confirmed meningitis, probably bacterial. Culture of the CSF determined the cause to be Streptococcus pneumoniae. The boy was admitted to the hospital for antibiotic therapy and close monitoring.

Subsequently, the boy developed a facial nerve palsy, a complication of the meningitis. His symptoms mimic Bell's Palsy.

Questions to consider:

1. What is the course of the facial nerve?
   1. Where does it emerge from the brain?

      lower border of the pons

   2. What foramen does it enter and exit from the skull?

      internal auditory meatus, stylomastoid foramen

   3. Name the ganglion it is associated with.

      geniculate ganglion

   4. Name the five end branches.

      temporal, zygomatic, buccal, mandibular, cervical

   5. What muscles does it innervate?

      the muscles of facial expression, platysma, stylohyoid, posterior belly of digastric, and stapedius

   
   
2. What are the clinical signs of Bell's Palsy?

   Unilateral flaccid paralysis of the muscles innervated by the facial nerve, leading to loss of expression. The patient will be unable to smile, lift their eyebrow, or close their eyelid on the affected side of the face.

3. Hyperacusis is noted. What is this? What motor branch of the facial nerve is affected?

   Hyperacusis is increased sound perception. This happens because the stapedius (a muscle of the middle ear) is innervated by a branch of the facial nerve. Normally, stapedius serves to dampen large vibrations of the tympanic membrane resulting from loud noises by contracting and inhibiting movement of the stapes. So, the "nerve to the stapedius" is affected.

4. Facial pain or lack of sensation implies that which nerve is affected?

   Sensation of the face is from the trigeminal nerve (CN V).

5. The physician orders lubricating eye-drops to be applied as needed. Why?

   Because the eyelid cannot close upon reflex or conscious effort (unless it is closed manually i.e. with one's hand), the patient with facial nerve palsy is at risk for corneal irritation. Closing the eye is a function of the orbicularis oculi muscle.

A 65-year-old man complained of inability to shut his right eye, difficulty in moving food around his mouth and weakness on the same side of his mouth with slight numbness on the right cheek. The problem started a few weeks ago following an excisional biopsy of a right facial lump that proved to be a benign parotid tumor. The surgeon was able to verify an area of mild numbness on the right cheek. Upon examining facial muscles, he suspected an injury to facial nerve branches that must have happened during the biopsy. He suggested intensive physiotherapy sessions and regular checkups to monitor the patient's progress.

Questions:

1. How would you explain the patient's numbness on the right cheek?

   The most likely reason is an injury to the maxillary division of the trigeminal nerve.

2. Which facial muscles do you think are responsible for the patient's complaints?

   The main muscles are: orbicularis oculi, buccinator, and orbicularis oris.

3. How would you test for these muscles?

   For the orbicularis oculi: ask the patient to shut his eye as tightly as he can. The affected eye is either not closed at all, in which case the eyeball rolls upward to make up for the failure of the lid to descend. For buccinator and orbicularis oris: ask the patient to whistle. If he is unable to do so, ask him to smile or show his upper teeth, the mouth is then drawn to the healthy side. Ask him to inflate his mouth with air and blow out his cheeks. Tap with a finger in turn on each inflated cheek. Air can be made to escape from the mouth more easily on the weak or paralyzed side.

4. What other functions of the facial nerve need to be checked?

   Test sense of taste on the anterior part of the tongue and ask the patient to raise his eyebrows.

An 18-year-old woman went to see her dentist for a regular checkup. During the visit, the doctor discovered that her lower third molars ("wisdom teeth"), which had appeared to be erupting fine on her last visit, had begun to cause crowding in the patient's mouth. He was afraid that they might eventually cause her discomfort, and since her teeth were currently straight, he recommended that she have the third molars extracted. She agreed, and returned the following week for the procedure. Before the dentist began to work, the patient told him that she had a low pain tolerance and asked that he make sure that her mouth was fully anesthetized. The dentist promised that he would take care of it , and then proceeded to inject the anesthetic in the mucous membrane on both sides of the patient's mouth. The teeth were removed without incident; however, when the dentist finished, the patient found that she could not close her mouth. The dentist apologized, saying that he must have dislocated her jaw, but that he could fix it easily and she would suffer no lasting effects. He then reduced the dislocated jaw by pressing downward on the remaining molars until the mandible slipped back into place. He then warned her not to attempt to chew any food until the anesthetic had worn off and she was able to feel her tongue and lower lip again, lest she damage them by chewing on them.

Questions to consider:

1. What nerve(s) would need to be anesthetized in order to prevent pain during a lower third molar extraction?

   The inferior alveolar nerve, a branch of the mandibular nerve (V3), provides sensory innervation to all of the teeth of the lower jaw.

2. Why were the patient's lower lip and tongue numb?

   The lower lip was numb because the chin and lower lip receive sensory innervation from the branch of the inferior alveolar nerve called the mental nerve. When the inferior alveolar nerve is anesthetized near the mandibular foramen, as in most dental procedures, all sensory stimuli from branches distal to that point will be blocked. The tongue (as well as the mandibular gingiva) is deadened at the same time that the inferior alveolar nerve is anesthetized because the lingual nerve passes beneath the mucosa in close proximity to the inferior alveolar nerve medial to the ramus of the mandible.

3. What joint was dislocated during the tooth extraction and how did this occur?

   The temporomandibular joint (TMJ) was dislocated during the tooth extraction, probably due to excessive downward stress during the procedure that caused the head of the mandible to pass anterior to the articular tubercle to a position beneath the zygomatic arch. Downward and backward pressure on the patient's lower molars generally reduces this dislocation fairly easily.

4. Some patients occasionally experience temporary paralysis of the muscles of facial expression or of mastication following a dental procedure. Why do you think this might happen?

   If a sufficiently large amount of anesthetic is injected (or if the parotid fascia is pierced by the needle), it may spread through the soft tissue to the parotid gland, where the facial nerve will be anesthetized, leading to paralysis of the muscles of facial expression. An analogous event would be true for paralysis of the muscles of mastication.

5. When dental work is performed on the lower teeth, anesthetic injected at a single point is often adequate to produce complete local anesthetization of all the teeth on a given side. The same is not true for the upper teeth. Why not? How do they have to be anesthetized?

   The teeth of the upper jaw are innervated by a series of branches from the posterior, middle, and anterior superior alveolar nerves, which are derived from the maxillary nerve (V2). There is no convenient way to anesthetize the entire maxillary nerve and thus provide nerve block to all of the maxillary teeth, as can be done with the mandibular teeth. Instead, the nerves to each tooth must be anesthetized by injecting the anesthetic into the gingiva around each tooth.

6. What are the anatomical structures that prevent joint dislocation?

   The fibrous capsule of the TMJ is thickened laterally to form the lateral ligament, which reinforces the lateral part of the capsule. Other ligaments (the stylomandibular and sphenomandibular) have a minor role in stabilizing the joint.

You were asked to assess the case of 20-year-old woman whose impacted right lower wisdom tooth was surgically removed. The operation lasted about an hour, and the dental surgeon suspected that some nerves might have been bruised during the operation. The patient presented with loss of sensation in the gums of her lower jaw, and her mouth was slightly dry. You examined taste sensation in the tongue and found that it was diminished in the anterior two-thirds but it was normal in the posterior portion.

Questions:

1. Which nerve is most likely to have been bruised in this patient?
   

   The lingual nerve, which is a branch of the posterior division of the mandibular nerve (CN V₃).
   

2. How would you explain the patient's complaints?
   

   The lingual nerve supplies general sensory fibers to the anterior two-thirds of the tongue, the floor of the mouth and the gums of the mandibular teeth. It carries the chorda tympani nerve, which carries taste fibers from the anterior two-thirds of the tongue and parasympathetic innervation to the submandibular and sublingual salivary glands.
   

3. Which nerve is responsible for sensation in the posterior third of the tongue?
   

   The glossopharyngeal (CN IX) supplies taste and general sensation to the posterior third of the tongue.
   

A medical student was celebrating the end of midterm exams with her friends in a seafood restaurant when she started feeling a prickling sensation in her neck after swallowing a large bite of smoked fish. The pain was getting worse, and attempts to clear it with drinks failed. At the emergency room a plain X-ray of her neck showed a tiny fish bone lodged in the lower part of the pharynx. The bone was quickly removed under general anesthesia, and the patient was discharged a few hours later.

Questions to consider:

1. Which are the most usual places for swallowed foreign bodies to be lodged?
   

   The piriform recess and the valleculae on either side of the median glosso-epiglottic fold.

2. What is the piriform recess?
   

   This is a small, pear-shaped depression of the laryngopharyngeal cavity on each side of the inlet of the larynx. It is separated from the inlet by the aryepiglottic fold. Laterally the piriform recess is bounded by the medial surfaces of the thyroid cartilage and the thyrohyoid membrane. The branches of the internal laryngeal and inferior laryngeal nerves (continuation of recurrent laryngeal) lie deep to the mucous membrane of the piriform recess.

3. Fish bones and other foreign bodies may pierce the mucous membrane of the recess and cause injury to the internal laryngeal nerve. What are the possible consequences of this injury?
   

   Injury to the internal laryngeal nerve will result in anesthesia of the laryngeal mucous membrane as far inferiorly as the vocal folds.