Laryngeal anatomyLaryngeal anatomy, , physiology and disordersphysiology and disorders

Prof. Alexander I. YashanProf. Alexander I. Yashan

Laryngeal AnatomyLaryngeal Anatomy

• The larynx is the organ of voice production

• It is a part of the respiratory tract lying between the trachea and the pharynx, has a framework of cartilages, muscles and ligaments

• The entrance to the larynx is guarded by a “U”-shaped hyoid bone, which is also the supportive structure for the tongue

Laryngeal StructuresLaryngeal StructuresMuscles are cartilages support the

larygngeal framework, the key structures are:

• Epiglottis - flexible, elastic, leaf-like structure

• Thyroid - largest cartilages• Corniculate - remnant in humans• Arytenoid - on the border of

cricoid• Extrinsic (supporting) and

intrinsic (influencing laryngeal motion) muscles

Vocal CordsVocal Cords

• The true vocal cords project into the laryngeal cavity

• paired vocal cords originate from the thyroid cartilage, near the thyroid notch

• They have a common anterior attachment of the folds is common (comissure)

• Medial borders are free to vibrate

• The space between the vocal folds - glottis – supraglottic / subglottic regions

The Mucosal WaveThe Mucosal Wave

Vocal Cord AnatomyVocal Cord Anatomy

• Thin layer of epithelium on lamina propria

• Recent studies show a delicate and complex basement membrane structure between epithelium and the superficial layer of lamina propria

• Strong connection between basement membrane attachment and healing of vocal cord

Factors that effect phonationFactors that effect phonation

• Respiratory tract infection• Asthma• Smoking• Medication• Irritants: dust, fumes, smoke• Vocal abuse: singers• External Trauma

• Laryngeal injuries: prolonged intubation

• Foreign bodies• Degenerative disorders:

papilloma, granuloma, vocal cord lesions etc.

• Sudden voice change may be due to haemorrhage into the vocal cords

• Hoarseness following upper respiratory infection is due to acute inflammation of the larynx

Changes in Voice ProductionChanges in Voice Production

• Change in airflow pressure generated in the lower respiratory tract

• Mass on the vocal cords• Neurological control of vocal

cord movement• Change in vocal cord tension• Stiffness and vibration• Stridor - indicates partial

obstruction of upper airway, mostly in children

Congenital AbnormalitiesCongenital Abnormalities

• Laryngomalacia - softening of laryngeal cartilage - surgery is not usually required

• Atresia and Webs - lead to opening of the airway by surgical intervention

• Laryngoceles - air-sack, causing a foreign body sensation in the throat, can be removed surgically

• Hemangioma - proliferation of a blood vessel leading to a mass; removed by laser surgery

Functional DisordersFunctional Disorders

• Abnormal vocal cord position - surgical intervention eg: medialisation

• Recurrent laryngeal nerve paralysis - all the internal laryngeal musculature is paralysed on the affected side. If the case is bilateral, the glottis is widened with CO2 laser surgery

Traumatic InjuriesTraumatic Injuries

• Vocal Abuse - often leads to formation of polyps and nodules which are removed surgically

• Intubation Injury -formation of heamatoma - usually heals by itself - or granulomas which can be surgically removed

• Foreign Bodies

InflammationInflammation

• Acute Laryngitis present with red, swollen cords, usually cured by antibiotics

• Specific Chronic Laryngitis - eg: Tubercolosis, Scleroma (granulation) in the sub-glottic space

• Non-Specific Chronic Laryngitis - usually caused by smoking

Benign tumors of the LarynxBenign tumors of the Larynx

• Vocal Cord Polyps - cause hoarseness and attacks of coughing, surgical removal

• Reinke’s Edema - Reinke’s space is a closed cleft under the vocal cord epithelium - the edema is always almost bilateral and usually affects smokers

Benign tumors of the Benign tumors of the LarynxLarynx

• Papilloma - benign epithelial tumor cause by viral infection, usually recurrent; causes hoarseness and respiratory obstruction

• Retention cysts - glazed, white cysts derived from the mucosal glands, effect phonation

SummarySummary

• Voice production is a compley function requiring fine neuromuscular control and coordination

• Sound varies according to mass, tension and lenght of the vocal folds

• Minor changes in anatomical structures as well as disease and pathology can greatly alter phonation

LARYNGEAL DISODERSLARYNGEAL DISODERSThe term "laryngitis" is frequently misused as a synonym for The term "laryngitis" is frequently misused as a synonym for hoarseness, but "laryngitis" refers to any acute or chronic, hoarseness, but "laryngitis" refers to any acute or chronic, infectious or noninfectious, localized or systemic inflammatory infectious or noninfectious, localized or systemic inflammatory process that involves the larynx. The clinic al presentation of process that involves the larynx. The clinic al presentation of laryngitis depends on its underlying cause, the amount of tissue laryngitis depends on its underlying cause, the amount of tissue swelling/edema, the region of the larynx primarily involved, and swelling/edema, the region of the larynx primarily involved, and the patient's age. Patients with laryngitis may present with one the patient's age. Patients with laryngitis may present with one or more symptoms: or more symptoms: dysphonia, odynophonia, dysphonia, odynophonia, dysphagia, odynophagia,dysphagia, odynophagia,cough,cough,dyspnea,dyspnea,and/or stridor. and/or stridor. The diagnosis is usually based on the history and the laryngeal The diagnosis is usually based on the history and the laryngeal examination, but it sometimes requires special diagnostic tests, examination, but it sometimes requires special diagnostic tests, such as cultures, blood tests, skin tests, pH monitoring, such as cultures, blood tests, skin tests, pH monitoring, and/or rad iographs.and/or rad iographs.

CHILDHOOD LARYNGITISCHILDHOOD LARYNGITIS

• The smaller pediatric airway is much more susceptible than the adult airway to obstruction from edema. Equivalent amounts of mucosal edema produce critical narrowing in children, but cause minimal or no symptoms in adults. Table 48-2 shows the effects of1 mm of edema on the airway of a neonate, a child, and an adult. Laryngitis is therefore more often a life-threatening illness requiring airway management in infants and children than in adults.

Common Viral LaryngitisCommon Viral Laryngitis• The most common cause of laryngitis is viral infection.

This type of nonobstructive laryngitis is clinically mild, and is often associated with a viral upper respiratory infection (URI). Patients may present with low-grade fever, mild dysphonia, cough, or rhinitis. Rhinovirus, parainfluenza, respiratorysyncytial virus, and adenovirus have been implicated. Other viral illnesses causing laryngitis include influenza, measles, mumps, pertussis, and chicken pox.

• The diagnosis may be based on the history and symptoms, so that examination of the larynx does not always need to be performed. When examined, the laryngeal mucosa is erythematous and edematous, with normal vocal fold mobility and no evidence of airway obstruction. Common viral laryngitis is usually self-limited, and treatment is aimed at providing hydration and humidification, but antipyretics and decongestants are frequently also prescribed.

Acute Laryngotracheitis (Croup)Acute Laryngotracheitis (Croup)

• Acute laryngotracheitis1 (croup) is a common viral infection which generally affects children younger than 5 years of age. Typically, this illness lasts from 3 to 7 days and it is common in the autumn and winter. Parainfluenza I is the most common lyimplicated viral agent, but parainfluenza II, influenza A, rhinovirus, and respiratory syncytial virus may also be causative. The child first develops a febrile URI followed dayslater by the classic "barky" or croupy cough; the cough is usually nonproductive and worsens at night.

• Usually, croup is self-limited, but if significant edema develops, progressive airway difficulty may ensue. Stridor with intercostal and supraclavicular retractions becomes prominent as the child struggles for air. In severe cases, with out treatment, the airway obstruction may progress, exhaustion may ensue, and complete airway obstruction may occur. Most often, the diagnosis is based on the history and on lateral neck radiographs, which usually reveal the classic "steeple sign," caused by subglottic narrowing due to edema.

Acute Laryngotracheitis (Croup)Acute Laryngotracheitis (Croup)• In laryngotracheitis, the subglottic larynx is the primary site of

inflammation and edema formation, although the trachea may also be involved. In severe cases, epithelial sloughing, associated with tenacious mucoid secretions, may accompany the inflammatory process, and further compromise the airway. It should be noted that the supraglottic larynx is usually unaffected in laryngotracheitis, and this helps differentiate it from other causes of airway obstruction in young children.

• Treatment is directed at reducing the edema, thinning the secretions, and in severe cases, establishing an airway. Intensive humidification and hydration are begun to help thin the secretions and soften the crusts in the airway. If symptoms worsen, aerosolized epinephrine treatments and high-dose corticosteroids are used to prevent further progression of the edema.2,3,4 If impending airway obstruction develops, intubation or tracheotomy is required to secure the airway and permitadequate pulmonary toilet. Antibiotics are indicated for secondary bacterial infection, which may be caused bystaphylococci, streptococci, or pneumococci.

Secondary Bacterial LaryngitisSecondary Bacterial Laryngitis • Some patients with laryngotracheitis progress to

develop secondary bacterial infection of the airway. These patients present with various degrees of airway obstruction, stridor, tachypnea, tachycardia, cough, fever, and drooling. This condition is more serious and it is usually attended by high fever and purulent drainage. This condition has the potential to obstruct the airway, and it requires prompt diagnosis andtreatment.5 The organisms usually responsible are Haemophilus influenzae, pneumococcus, and hemolytic streptococci. Antibiotic therapy should be directed at these organisms. When possible, culture and gram stain of the exudate should be obtained. Airway support is often needed in these patients.

Acute SupraglottitisAcute Supraglottitis• Children between 2 and 4 years of age are most often affected, and

most cases of supraglottitis occur in the winter and spring. Acute supraglottitis,6,7 also sometimes called "epiglottitis," is a life-threatening infection of the larynx, most often caused by Haemophilus influenzae type B. This condition is a medical emergency, because airway obstruction and death can develop rapidly. Typically, the illness begins and progresses rapidly, over 2 to 6 hours, with the onset of fever, sore throat, and inspiratory stridor. The child's voice tends to be muffled, but a croupy cough is unusual. As the supraglottic structures become increasingly edematous, airway obstruction may develop. Affected children are frightened and ill-appearing; often stridulous, and sitting upright in the "sniffing" position. They often drool because swallowing is very painful.

Acute SupraglottitisAcute Supraglottitis• A presumptive diagnosis of supraglottitis is based on the

history and clinical findings, but since laryngeal examination in the emergency department may precipitate airway obstruction, it is not recommended. Lateral soft-tissue radiographs typically reveal the classic "thumb" sign of the edematous epiglottis. In addition, the entire supraglottis may be hazy and indistinct with a dilated hypopharynx.

• When airway obstruction is severe, treatment should not be delayed to obtain radiographs. If radiographs are deemed necessary, the child should be constantly attended by personnel capable of immediate intubation if airway obstruction should occur.

Acute SupraglottitisAcute Supraglottitis• Children with suspected supraglottitis should be taken to the

operating room immediately to establish the diagnosis and secure the airway. The child is transported to the operating room by the parents, an otolaryngologist, and an anesthesiologist. At the time of direct laryngoscopy, the epiglottis usually appears veryswollen and cherry red, as do the aryepiglottic folds and falsevocal cords. The true vocal folds and subglottis usually appearvirtually normal.

• Treatment secures the airway and then provides antimicrobial and supportive care. Drawing blood, starting intravenous lines, obtaining a rectal temperature, and other necessary procedures are performed after the airway is established. After controlled anesthesia and diagnosis, the patient should be orally intubated. The oral endotracheal tube can then be converted to a nasotracheal tube, with direct visualization of the glottis as the orotracheal tube is removed, or a tracheotomy may be performed. (Instruments necessary for rigid bronchoscopy and tracheotomy must be ready in the operating room in case the airway is lost before intubation). In some settings, such as institutions without skilled pediatric intensive care staff available around the clock, tracheotomy may be preferred to endotracheal intubation, because it is easier to secure and maintain in the small patient with a tenuous airway

Acute SupraglottitisAcute Supraglottitis• Antimicrobial therapy is initiated against Haemophilus influenzae.

Extubation is usually possible after 48 to 72 hours, at which time the edema has subsided sufficiently to allow an air leak around the endotracheal tube. Direct laryngoscopy or fiberoptic laryngoscopy are the most reliable techniques to ensure resolution of the inflammation before extubation.

• Haemophilus influenzae type B polysaccharide vaccine has been available since 1985 for children older than 18 months of age.Since 1988 conjugate vaccines have made possible the immunization of children beginning at 2 months of age. Immunization has resulted in a dramatic decrease in the incidence ofsupraglottitis.7 Although H. Influenzae remains the leading cause of supraglottitis, beta-hemolytic streptococci and staphylococcusmay also cause supraglottitis.

• Unfortunately, the mortality rate for supraglottitis today remains quite significant despite advances in airway management.This is because the diagnosis may be missed in the early stagesof the illness, (often mistaken for croup) with rapid progression of airway obstruction. Differentiating acute supraglottitis from laryngotracheitis is not always easy, but this differentiation is essential.

Laryngeal DiphtheriaLaryngeal Diphtheria• Laryngeal diphtheria is very uncommon; however, outbreaks of

diphtheria have recently been reported in eastern Europe, believed to be due to low immunization rates.8 It is caused by Corynebacterium diphtheriae and generally affects individual solder than 6 years of age. A febrile illness of slow onset associated with sore throat and dysphonia is followed by progressive airway obstruction.

• The organism causes an exudative inflammatory response of the mucous membranes, which results in a thick, gray-green, plaque-like membranous exudate over the tonsils, pharynx, and larynx. Characteristically, the exudate is difficult to dislodge, and it bleeds when it is removed. Cultures and smears are obtained for confirmation of the diagnosis.

• Treatment consists of establishing a safe airway, administrationof diphtheria antitoxin, and erythromycin or penicillin toeradicate the organism. Intubation is contraindicated because it may dislodge a plaque and cause airway obstruction, thus, tracheotomy is often performed. Mortality results largely from the neuropathic responses to the diphtheria toxin. If the patienth as been previously immunized against diphtheria, the disease may still occur, but tends to be mild.

Laryngopharyngeal RefluxLaryngopharyngeal Reflux• Laryngopharyngeal reflux (LPR), the reflux of gastric contents

into the laryngopharynx, is ubiquitous in pediatric otolaryngology, yet the diagnosis may be difficult to make. LPR is associated with laryngomalacia, vocal nodules, polyps ,granulomas, laryngeal and tracheal stenosis, and laryngospasm. LPR may also play a causal role in asthma, sudden infant death syndrome, bronchopulmonary dysplasia, and aspirationpneumonia.9,10

• A high index of suspicion is necessary for LPR tobe considered in cases of laryngitis; unfortunately, the only reasonably sensitive diagnostic test for this condition is ambulatory 24-hour double-probe pH monitoring.9 Other tests, such as barium esophagography, radionuclide scanning, and the lipid-laden macrophage test, lack sufficient diagnostic sensitivity to be of value in most cases.

Spasmodic CroupSpasmodic Croup• Spasmodic or false croup is a noninfectious form of

laryngeal inflammation, possibly related to allergy or reflux laryngitis. It generally affects children 1 to 3 years of age. It is occasionally associated with an URI, but not with a significant febrile illness. The child usually wakes at night with a "barky“ cough, stridor, and mild dyspnea. The coughing paroxysms may be followed by vomiting, which may terminate the attack. These episodes may occur as an isolated event or recur over 2 to 3nights. The child is usually asymptomatic during the day.

• Examination shows mildly erythematous laryngeal mucosa, with subglottic edema. Humidification is usually all that is required to alleviate the symptoms. Spasmodic croup may be confused with laryngotracheitis and with LPR-related laryngospasm.

Spasmodic Croup Spasmodic Croup Differential DiagnosisDifferential Diagnosis

• Inflammatory forms of laryngitis may result in airway obstructionand should be diagnosed accurately and promptly to provide appropriate treatment.5 The most common causes of obstructive laryngitis in children are laryngotracheitis, supraglottitis, and LPR. However, in dealing with a child with dysphonia, stridor, or airway obstruction, other diagnoses should be considered. These include foreign bodies, respiratory papillomas,laryngeal cysts and hemangiomas, subglottic stenosis, bacterial tracheitis, and retropharyngeal abscess. If the infant or child develops laryngeal inflammation (with or without airway obstruction), and there are no definitive signs of infection, LPR should be considered as the most likely diagnosis

ADULT LARYNGITISADULT LARYNGITIS• Laryngitis in adults is usually less serious

than in childrenbecause the larger adult larynx can accommodate swelling withoutobstructing as readily. Most commonly, adult laryngitis is causedby a viral URI, smoking, or LPR. Unlike children, adults can havechronic laryngitis that may go unrecognized for many years, butlike children, adults may occasionally develop laryngotracheitisand supraglottitis.

Viral LaryngitisViral Laryngitis

• Infectious laryngitis in adults is most commonly associated with a viral URI. Patients present with a generalized viral syndrome and dysphonia that is characterized by voice breaks, episodic aphonia, hoarse cough, and a lowering of the vocal pitch.

• Rhinoviruses are the most common causative agents. Characteristically, the laryngeal mucosa is erythematous and edematous, especially over the true vocal folds. The disease is self-limited and is treated symptomatically with humidification, voice rest, hydration, smoking cessation, cough suppressants, and expectorants. Antibiotics are indicated only for secondary bacterial infection.

Bacterial LaryngitisBacterial Laryngitis• Supraglottitis is manifested by fever, sore throat, a muffled

voice, odynophagia, and dyspnea. The diagnosis is usually made by observing the swollen, red supraglottic structures by fiberopticlaryngoscopy or by detecting the swollen epiglottis/supraglottison a lateral neck radiograph. Haemophilus influenzae is the most common organism, but Streptococcus pneumoniae, Staphylococcus aureus, and hemolytic streptococci are also found. Close observation of the adult patient with serial fiberoptic examinations is appropriate, with intubation or tracheotomy reserved for progressive airway obstruction. Patients whose symptoms progress rapidly over less than 24 hours are at high risk for airway compromise.11,12 Conservative measures include humidification, hydration, corticosteroids, and intravenous antibiotics. Epiglottic abscess is an uncommon complication of bacterial laryngitis, and it occurs more commonly in adults than in children. Tracheotomy followed by drainage is the treatment of choice.

NONINFECTIOUS LARYNGITIS IN NONINFECTIOUS LARYNGITIS IN ADULTSADULTS

• Laryngopharyngeal Reflux (LPR)• Of all the causes of laryngitis in adults, LPR is probably the

most common. It has been estimated that reflux affects 50 million Americans, and that as many as 50% of patients with laryngeal complaints have reflux-related causes.13,14 LPR may be associated with an acute, chronic, or intermittent pattern of laryngitis, with or without granuloma formation. LPR has also been implicated in the development of laryngeal carcinoma and stenosis, recurrent laryngospasm, crico arytenoid fixation, and many other conditions, including globus pharyngeus, cervical dysphagia, bronchiectasis, asthma, and chronic cough.15,16 The highest reported association (92%) is with subglottic stenosis (inchildren and adults).13

Laryngopharyngeal Reflux (LPR)Laryngopharyngeal Reflux (LPR)• Gastroenterologists consider reflux patients who denygastrointestinal

symptoms to be "atypical refluxers," but they are quite typical of the patients encountered in an otolaryngology practice. Otolaryngology patients with LPR are probably under-diagnosed and under-treated, because the signs, symptoms, and mechanisms of LPR are quite different than those seen in gastroenterology patients, who characteristically have heartburn, regurgitation, and esophagitis. In addition, when compared to esophagitis patients, LPR patients have up rightreflux, normal esophageal acid clearance, and normal esophagography. Consequently, LPR patients usually present with symptoms of dysphonia, cough, and frequent throat clearing, butoften deny having symptoms of heartburn.(Table 48-4)

• Examination of the larynx may reveal a variety of findings. Posterior laryngitis, demonstrating red arytenoids with interarytenoid mucosal hypertrophy, is commonly seen with LPR. Subglottic edema forming a "pseudo-sulcus vocalis" is alsofrequently seen. The larynx may instead show diffuse edema, Reinke's space edema, or mucosal thickening without significant erythema. This may cause ventricular effacement. Diffuse erythema with granular, friable mucosa, and vocal process granuloma(s), with or without associated laryngeal edema and erythema are also seen. Although granulomas of the vocal process may be caused by vocal abuse and endotracheal intubation, available data indicate that LPR plays a role in most cases

Laryngopharyngeal Reflux (LPR)Laryngopharyngeal Reflux (LPR)

• Ambulatory 24-hour double-probe pH monitoring is the current "gold standard" for the diagnosis of LPR. (The second probe is placed in the hypopharynx, behind the laryngeal inlet). This technique is highly sensitive and specific for LPR and also delineates each patient's reflux pattern, allowing treatment to be somewhat individualized.17

• The treatment of LPR includes dietary and life style modifications, and antireflux medication, such as an H2-blocker or proton pump inhibitor (PPI), such as omeprazole. PPIs are the most effective antireflux medicine available, because unlike theH2-blockers, they can achieve total suppression of gastric acidproduction. With H2-blockers, treatment fails in approximately one-third of LPR patients. Patients who fail medical anti-refluxtherapy may require a surgical anti-reflux procedure, such as fundoplication

Traumatic LaryngitisTraumatic Laryngitis• "Traumatic laryngitis" is commonly caused by vocal abuse, such as

excessive shouting or yelling, but it can also result from persistent coughing, muscle tension dysphonia, or direct endolaryngeal injury. Such patients present with various degrees of dysphonia and odynophonia. The mucosa of the true vocal folds is hyperemic from dilated vessels on the vocal fold surface. Edema within Reinke's space develops, and submucosal hemorrhage may occur. This form of laryngitis is self-limited and subsides within a few days when treated with voice conservation and humidification.

• Thermal Injury• Laryngitis due to thermal damage to the larynx is well recognized.

Patients complain of dysphonia, odynophagia, andodynophonia. Exposure of the larynx to steam, smoke, very hot liquids or food (particularly if microwaved) leads tosupraglottic edema and erythema. It is more common in children. Laryngeal edema due to exposure to free-base cocaine may also present a diagnostic dilemma. Treatment of such injuries is with humidification, corticosteroids, and airway observation or intubation if the larynx is severely edematous.

AngioedemaAngioedema• Acquired angioedema is an inflammatory reaction characterized by

vascular dilation and increased vascular permeability. This can be caused by a variety of substances particularly angiotensin-converting enzyme (ACE) inhibitor medications and is potentially life-threatening if the larynx is involved.

• Hereditary angioedema is an autosomally dominant deficiency of C1esterase inhibitor that leads to recurrent attacks of mucocutaneous edema. Diagnosis is based primarily on the history, although the offending agent may not be readily apparent. Patients present with edema that may involve the face, oral cavity, oropharynx, or larynx. The onset is rapid and may be associated with pruritus. Dysphonia is common with laryngeal involvement.

• Treatment must be aggressive. Supplemental oxygen, epinephrine, corticosteroids, antihistamines, and aminophylline are the mainstays of therapy. However, ACE inhibitor related angioedemais not believed to be IgE mediated and therefore such patients may be refractory to this therapy. If progressive airway obstruction develops, intubation or tracheotomy may be required. Chronic "pretreatment" of hereditary angioedema with danazol appears to elevate levels of functional C1 esterase inhibitorand may help to prevent recurrent episodes.

Allergic LaryngitisAllergic Laryngitis• Allergy-mediated inflammation involving the larynx is controversial. It

may be responsible for symptoms of chronic and recurrent dysphonia in some patients. Anaphylaxis is well known and will not be re viewed here. Laryngeal chemical sensitivity and delayed food allergies are less well known. Examination may reveal glottic edema and erythema as well as muscular tension dysphonia. The most common triggering substances are insecticides, phenol, and petroleum- based compounds. Diagnosis is based on the history, ruling out more common causes such as LPR, a standard allergy evaluation, and challenge testing with the suspected triggering agent(s).

• The contribution of vocal abuse, misuse, LPR, and secondary gain after exposure(s) to such compounds is unknown. Treatment begins with optimizing vocal hygiene with hydration, conservative voice use, and treating LPR, if it is present. Training with as peech-language pathologist and avoidance of the incitingsubstances are also critical.

Relapsing PolychondritisRelapsing Polychondritis• Relapsing polychondritis is characterized by

episodes of inflammation and fibrosis with subsequent destruction of the cartilage of the ears, nose, larynx, and tracheo-bronchial tree. Laryngeal disease occurs in more than half the cases and is manifested by dysphonia, dysphagia, and throat pain. Airway involvement leads to the high mortality seen with this disease. Treatment includes dapsone, corticosteroids and other immunosuppressive drugs. Tracheotomy may be necessary.