An Upper Gastrointestinal Endoscopy (EGD) is a routine medical procedure used to examine the lining of the upper digestive system. This involves passing a thin, flexible tube (the endoscope) through the mouth and throat to visualize the esophagus, stomach, and the beginning of the small intestine. The procedure is highly safe, and serious complications are infrequent. Concerns about potential vocal cord damage arise because the endoscope must navigate the pharynx, the area immediately surrounding the voice box. Although the risk of permanent injury is very low, the delicate tissues in the throat are exposed to the instrument, making temporary irritation or minor trauma a possibility.
The Path of the Endoscope and Vulnerable Anatomy
The endoscope begins in the oral cavity and passes through the pharynx, a shared passageway for air and food, before entering the esophagus. The larynx (voice box) is located centrally in the throat, just in front of the esophageal entrance. The vocal cords (true vocal folds) are the two bands of muscle tissue housed within the larynx that generate sound for speech.
The endoscope bypasses the larynx and enters the esophagus via the upper esophageal sphincter. To avoid the airway, the instrument is typically guided into the pyriform fossa, a recess on either side of the larynx. This area is extremely close to the structures controlling vocal cord movement, specifically the arytenoid cartilages and the recurrent laryngeal nerve. Because the endoscope navigates this tight anatomical space, the tissues lining the throat and the vocal cords are vulnerable to contact.
How Vocal Cord Injury Occurs
Vocal cord injury resulting from an EGD typically involves two main categories: mechanical trauma and chemical irritation.
Mechanical Trauma
The most direct cause is physical contact or friction from the endoscope during insertion or withdrawal. This is more likely if the patient has difficulty relaxing or if the throat anatomy makes scope passage challenging. Contact can lead to superficial scrapes, bruising, or localized swelling of the vocal cord tissue.
A more serious, though exceedingly rare, mechanical injury is vocal cord paralysis. This severe complication is hypothesized to occur when the endoscope tip or the gag reflex applies pressure to the pyriform sinus area. Such pressure can cause temporary or prolonged damage (neuropraxia) to the recurrent laryngeal nerve, which controls most vocal cord movement.
Chemical Irritation (Reflux Laryngitis)
Chemical irritation, often manifesting as reflux laryngitis, is another factor that can damage the vocal cords after endoscopy. The procedure can temporarily compromise the function of the upper and lower esophageal sphincters, which normally prevent stomach contents from backing up. Gastric acid and pepsin can then reflux into the laryngopharynx, causing chemical burns and inflammation of the vocal cord lining. This irritation is compounded because many patients temporarily stop anti-reflux medication before the procedure, leading to increased acid exposure.
Identifying Post-Procedure Symptoms
Patients should distinguish between expected post-procedure irritation and signs of true vocal cord trauma. Almost all patients experience a mild sore throat, a normal response to the endoscope passage that typically resolves within one to two days. Hoarseness (dysphonia) is also common, usually due to transient swelling and irritation of the vocal folds.
Symptoms that persist beyond 48 hours or increase in intensity warrant closer attention. Persistent hoarseness lasting a week or more, or pain upon swallowing (odynophagia), should prompt consultation with a healthcare provider. If a more significant injury, such as swelling or nerve irritation, has occurred, the hoarseness may last for two to three weeks.
Any symptom related to breathing difficulty, such as stridor (a high-pitched, noisy sound when inhaling), is a medical emergency requiring immediate attention. This uncommon symptom can signal significant laryngeal swelling or bilateral vocal cord paralysis, which compromises the airway. If hoarseness is accompanied by a sensation of a lump in the throat or if the voice does not improve after several days, a specialist evaluation may be necessary to rule out complications like a granuloma.
Treatment and Healing
Most cases of post-endoscopy vocal irritation are self-limiting and heal spontaneously with supportive care. The primary treatment is voice rest, meaning avoiding unnecessary talking, shouting, or whispering for 24 to 48 hours to allow superficial tissue recovery. Hydration is also key, as keeping the throat moist helps soothe irritated mucous membranes.
Supportive care measures include:
- Using warm saltwater gargles to reduce inflammation and relieve soreness.
- Taking over-the-counter throat lozenges containing soothing agents like menthol.
- Using a humidifier, especially during sleep, to prevent the throat from drying out.
If hoarseness or discomfort persists beyond a few days, or if initial symptoms were severe, a follow-up with the endoscopist or a referral to an otolaryngologist (ENT specialist) may be required. Specialists can perform a focused laryngoscopy to visualize the vocal cords and determine the cause of persistent symptoms. For significant swelling, temporary use of anti-inflammatory medications, such as corticosteroids, may be considered. The long-term prognosis is positive, with almost all complications resolving completely over time.