Introduction
There are a number of conditions that can cause a change in the quality of the human voice leading to hoarseness. Before I explain some of the causes of hoarseness of the throat I will briefly explain the anatomy of the upper airway.
Here is a picture that compares the anatomy of the upper airway of a human to the anatomy in a chimpanzee (thanks to www.indiana.edu for this link).
The point that was made in this illustration is that in humans the crossing of the food pathway is anatomically much lower than in the chimpanzee. Also the chimpanzee has a much bigger lid (called the epiglottis) that protects the upper opening of the larynx from choking. As humans depend on protective reflexes to prevent choking spells, we need to be aware of the following facts:
- We need to realize that we can only do one thing at a time: either eat or breathe. If we want to breathe while swallowing or if we want to swallow while breathing, we likely will choke (meaning that food particles want to enter into the larynx causing us to cough).
- When the Central Nervous System is suppressed, as after too much alcohol, during multi-drug interaction in the elderly or during a period of unconsciousness, the protective reflexes do not work well any more and there is a danger of aspiration pneumonia.
Below I listed some common reasons for hoarseness of the throat (modified according to Ref. 2, p. 1760). I will comment briefly on each of these conditions further below.
Common causes of hoarseness
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malformations : congenital macroglossia or craniofacial anomalies
infections : croup, laryngitis, epiglottitis, fungal larynx infection, diphtheria
granulomatous diseases : tuberculosis, lupus, leprosy, syphilis
angioedema : acute swelling due to allergies
gastroesophageal reflux disease : GERD can lead to micro aspirations of gastric acid into the upper larynx during deep sleep
voice abuse : vocal fold nodules are caused by this, called “singer’s nodules”, “preacher’s nodules” or “screamer’s nodules”
vocal cord polyps, granulomas and cysts : all of these changes occur because of voice abuse; intubation during surgery can cause granulomas
vocal cord paralysis: cancer, neck surgery and infection are common causes
neurological illness : Parkinson’s disease, myasthenia gravis, ALS (Lou Gehrig disease)
foreign body aspiration : sometimes masked as an asthma attack (sudden wheeze with breathing)
larynx cancer (=throat cancer): cancer and other tumors can change voice
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Malformations
With the importance of head and neck shape for the proper swallowing and breathing mechanism as indicated above, it is easy to see that a congenitally large tongue (macroglossia) or a malformed head shape (craniofacial anomaly) can cause problems. A pediatric maxillofacial surgeon and pediatric ENT surgeon likely should assess the child as soon as possible after birth. Some of the problems can wait, others have to be fixed right away (Ref. 2, p. 1761).
Infections
Viral infections cause croup and laryngitis. Haemophilus influenzae and other bacteria can cause epiglottitis, which has been dealt with under this link. Fungal infections can also lead to hoarseness of the throat. Diphtheria, although rare in countries that have childhood vaccination programs, is still very common in development countries and can be a serious cause of hoarseness of the throat. Further symptoms, findings and treatment are dealt with under this link (Ref. 2, p. 1762).
Granulomatous diseases
With granulomatous diseases one of the first signs is hoarseness of the voice, but shortly after there is an chronic persistent cough that develops. There might be coughing up of blood as well, as the granulomatous tissue around the pharynx tends to bleed. Tuberculosis is the most common infectious granulomatous disease and has been dealt with under the indicated link. Other diseases and their links are syphilis, leprosy and lupus (Ref. 2, p. 1762).
Angioedema
Urticarial rashes and angioedema are allergic conditions where highly active circulating immunoglobulin IgE antibodies suddenly bind to an allergen like peanut protein causing immediate swelling and in the throat a possible acute airway obstruction. Similar abrupt angioedema reactions can take place with allergies to bees or wasps. It is important for these individuals to carry medical alert bracelets and for onlookers to call 911 for the emergency response team. Adrenaline by inhalation or 0.5 ml of 1:1000 dilution subcutaneously can be life saving the sooner it is given (Ref. 2, p. 1762).
Gastroesophageal Reflux Disease (GERD)
With an incompetent sphincter in the lower esophagus gastric acid can flow up the esophagus and at night when the patient is deeply asleep there is a danger that acid might be aspirated. Even a small amount of acid at the entrance to the larynx can lead to devastating laryngeal scarring, granulomas, polyps and cysts (Ref. 2, p. 1762).
Voice abuse
With strain of the voice in professional speakers, teachers, sport coaches etc., structural changes of the vocal folds are happening. These structural changes lead to a monotonous, breathy and harsh voice. If speech therapy and voice training is instituted at this stage this condition is reversible (Ref. 2, p. 1763).
Vocal cord paralysis
The vocal cords are supplied by the laryngeal nerves. If there is disruption from cancer, or if surgery to the thyroid gland inadvertently destroys the nerve, the voice becomes hoarse or gets otherwise changed.
Throat Cancer
This topic has been dealt with under this link. In about 30% of cases of hoarseness there is an underlying tumor, either a primary larynx cancer or a secondary cancer that metastasized into the larynx from another original site (Ref. 2, p. 1766).For those of you who like to see a picture of larynx cancer here is a link to a site with a pictures of laryngoscopy findings regarding two throat cancers (thanks to www.tobacco-facts.info for this link).
References:
1. James Chin et al., Editors: Control of Communicable Diseases Manual, 17th edition, 2000, American Public Health Association.
2. Behrman: Nelson Textbook of Pediatrics, 16th ed., 2000, W. B. Saunders Company
4. Noble: Textbook of Primary Care Medicine, 3rd ed.,2001 Mosby, Inc.
5. Abeloff: Clinical Oncology, 2nd ed.,2000,Churchill Livingstone, Inc.
6. Ferri: Ferri’s Clinical Advisor: Instant Diagnosis and Treatment, 2004 ed., Copyright © 2004 Mosby, Inc.
7. Rakel: Conn’s Current Therapy 2004, 56th ed., Copyright © 2004 Elsevier
