Gag reflex abnormalities [Pharyngeal reflex abnormalities]
Gag reflex abnormalities [Pharyngeal reflex abnormalities]: Excerpt from Handbook of Signs & Symptoms (Third Edition)
The gag reflex — a protective mechanism that prevents aspiration of food, fluid, and vomitus — normally can be elicited by touching the posterior wall of the oropharynx with a tongue depressor or by suctioning the throat. Prompt elevation of the palate, constriction of the pharyngeal musculature, and a sensation of gagging indicate a normal gag reflex. An abnormal gag reflex — either decreased or absent — interferes with the ability to swallow and, more important, increases susceptibility to life-threatening aspiration.
An impaired gag reflex can result from a lesion that affects its mediators — cranial nerves (CNs) IX (glossopharyngeal) and X (vagus) or the pons or medulla. It can also occur during a coma, in muscle diseases such as severe myasthenia gravis, or as a temporary result of anesthesia.
Emergency interventions
If you detect an abnormal gag reflex, immediately stop the patient’s oral intake to prevent aspiration. Quickly evaluate his level of consciousness (LOC). If it’s decreased, place him in a side-lying position to prevent aspiration; if not, place him in Fowler’s position. Have suction equipment at hand.
History and physical examination
Ask the patient (or a family member if the patient can’t communicate) about the onset and duration of swallowing difficulties, if any. Are liquids more difficult to swallow than solids? Is swallowing more difficult at certain times of the day (as occurs in the bulbar palsy associated with myasthenia gravis)? If the patient also has trouble chewing, suspect more widespread neurologic involvement because chewing involves different CNs.
Explore the patient’s medical history for vascular and degenerative disorders. Then assess his respiratory status for evidence of aspiration, and perform a neurologic examination.
Medical causes
Basilar artery occlusion
Basilar artery occlusion may suddenly diminish or obliterate the gag reflex. It also causes diffuse sensory loss, dysarthria, facial weakness, extraocular muscle palsies, quadriplegia, and a decreased LOC.
Brain stem glioma
Brain stem glioma causes a gradual loss of the gag reflex. Related symptoms reflect bilateral brain stem involvement and include diplopia and facial weakness. Common involvement of the corticospinal pathways causes spasticity and paresis of the arms and legs as well as gait disturbances.
Bulbar palsy
Loss of the gag reflex reflects temporary or permanent paralysis of muscles supplied by CNs IX and X. Other indicators of bulbar palsy include jaw and facial muscle weakness, dysphagia, loss of sensation at the base of the tongue, increased salivation, possible difficulty articulating and breathing, and fasciculations.
Wallenberg’s syndrome
Paresis of the palate and an impaired gag reflex usually develop within hours to days of thrombosis. The patient may experience analgesia and thermanesthesia, occurring ipsilaterally on the face and contralaterally on the body, and vertigo. He may also display nystagmus, ipsilateral ataxia of the arm and leg, and signs of Horner’s syndrome (unilateral ptosis and miosis, hemifacial anhidrosis).
Other causes
Anesthesia
General and local (throat) anesthesia can produce temporary loss of the gag reflex.
Special considerations
Continually assess the patient’s ability to swallow. If his gag reflex is absent, provide tube feedings; if it’s merely diminished, try pureed foods. Advise the patient to take small amounts and eat slowly while sitting or in high Fowler’s position. Stay with him while he eats and observe for choking. Remember to keep suction equipment handy in case of aspiration. Keep accurate intake and output records, and assess the patient’s nutritional status daily.
Refer the patient to a therapist to determine his aspiration risk and develop an exercise program to strengthen specific muscles.
Prepare the patient for diagnostic studies, such as swallow studies, a computed tomography scan, magnetic resonance imaging, EEG, lumbar puncture, and arteriography.
Pediatric pointers
Brain stem glioma is an important cause of an abnormal gag reflex in children.
Book Source Details
- Book Title: Handbook of Signs & Symptoms (Third Edition)
- Author(s): Springhouse
- Year of Publication: 2006
- Copyright Details: Handbook of Signs & Symptoms (Third Edition), Copyright © 2006 Lippincott Williams & Wilkins.
More About DiGeorge's syndrome
More Medical Textbooks Online about DiGeorge's syndrome
Review other book chapters online related to DiGeorge's syndrome:
Medical Books Excerpts
- Pharyngitis
- "Professional Guide to Diseases (Eighth Edition)" (2005)
- [ read ]
- Pharyngitis
- "The 10-Minute Diagnosis Manual: Symptoms and Signs in the Time-Limited Encounter" (2000)
- [ read ]
Copyright notice for book excerpts: Copyright © 2008 Lippincott Williams & Wilkins. All rights reserved.
» Next page:
DiGeorge syndrome (Professional Guide to Diseases (Eighth Edition))
Rate This Website
What do you think about the features of this website?
Take our user survey and have your say:
Website User Survey
Medical Tools & Articles:
Next articles:
Tools & Services:
Medical Articles:
Forums & Message Boards
- Ask or answer a question at the Boards:
