Congenital Throat Problems

There is a range of congenital throat problems - some occurring alone and others as part of a syndrome. The underlying causes are varied but, as with any congenital disorder, they can be broadly divided into chromosomal abnormalities (mutations and inherited problems), diseases associated with prenatal infection, maternal drug abuse, environmental factors, iatrogenic causes and abnormalities of unknown aetiology. These are generally uncommon conditions, occurring in <5 in10,000 births.

Laryngeal abnormalities^[1]

These children present with a range of clinical manifestations, from a problem so mild that it is only found coincidentally later in life, to so severe as to cause death at birth without immediate treatment. This depends on the site and severity of the abnormality. The clinical manifestations include:

• Dyspnoea.
• Tachypnoea.
• Stridor.
• Weakened or abnormal cry.
• Episodes of cyanosis.
• Aspiration.

These children should have a thorough physical examination, mainly to rule out associated problems. Imaging is helpful to help identify the problem itself in conjunction with a specialist ear, nose and throat (ENT) evaluation. The former may include:

• Plain film anteroposterior (AP) and lateral views of the neck and chest - useful to help rule out any stenotic lesions of the airway.
• If inspiratory and expiratory films are difficult to obtain, airway fluoroscopy to view the dynamic properties of the trachea.
• A barium swallow can be used in cases of swallowing difficulty.
• CT and MRI scans are generally not helpful in these patients.

The gold standard for diagnosis is direct laryngoscopy and tracheobronchoscopy under general anaesthesia.

Laryngomalacia^[2]

• The most common congenital laryngeal abnormality (60% of all cases), where the larynx is soft and floppy and collapses during breathing due to abnormalities of the laryngeal cartilages.
• Three types have been proposed:
  • Type 1 - the aryepiglottic folds are tightened or foreshortened.
  • Type 2 - there is redundant soft tissue in any area of the supraglottic region.
  • Type 3 - associated with other disorders - eg, neuromuscular disease and gastro-oesophageal reflux.
• Infants present within the first few weeks of life (not necessarily at birth, typically at 4-6 weeks) with noisy respiration and inspiratory stridor which are worse in the supine position, when feeding or when agitated. Infants may also have gastro-oesophageal reflux but they are otherwise generally well, happy babies. Importantly, the cry is normal (if not, there may be an abnormality at or near the vocal cords). The abnormal sounds may best be heard just above the sternal notch.
• These problems initially worsen with age but tend to resolve by 18-24 months. Respiratory distress, failure to thrive and cyanosis are rare.
• Oxygen saturation should be monitored. Other investigations are not usually required if the baby is thriving but laryngoscopy and bronchoscopy may be performed in cases of diagnostic difficulty.
• Most of these children are managed conservatively with close observation (with particular note taken of any reflux disease). 99% of cases resolve spontaneously. In some cases, it may be worth considering putting the baby to bed in the prone position but consider the risk factors for sudden infant death syndrome (SIDS) first, and advise care to be taken to avoid soft bedding, pillows and blankets. Surgical intervention is only warranted with severe respiratory distress and may include tracheotomy, laryngoplasty or laser epiglottopexy.

Congenital neuromuscular problems in the larynx

Congenital vocal fold paralysis is the second most common congenital laryngeal abnormality (15-20% of all cases). It is usually idiopathic (47% of individuals) but may be seen where there is neuromuscular immaturity or where there are central nervous system (CNS) abnormalities (eg, Arnold-Chiari malformation, cerebral palsy, hydrocephalus, myelomeningocele, spina bifida, hypoxia or haemorrhage). Birth trauma can also cause paralysis for up to nine months.

• Bilateral paralysis presents in the infant, with varying degrees of respiratory distress. There may be a history of recurrent chest infections secondary to aspiration. Surgical intervention is frequent although the priority is to stabilise the airway, followed by a thorough evaluation of the problem.
• Unilateral paralysis may be asymptomatic or present with a hoarse cry and difficulty in feeding. These infants tend to have a stable airway and so investigations can be carried out less urgently. Many manage with speech therapy alone.

An ineffective cough is also a feature in these babies.

Diagnosis is with endoscopy and management depends of severity of symptoms (tracheostomy to simple observation). Nutritional support will also be considered in the child with bilateral paralysis. Other neuromuscular problems relate to a number of syndromes: cri du chat syndrome and arthrogryposis multiplex congenita.

Subglottic stenosis (SGS)^[3]

• This is the third most common congenital laryngeal abnormality (15% of all cases) but congenital SGS only accounts for 5% of all SGS cases. It is the most common cause for performing tracheostomy in infants. It is a narrowing of the subglottic airway due to a malformed cricoid cartilage.
• Acquired SGS was seen early in the 20th century secondary to trauma or infection (eg, syphilis, tuberculosis, typhoid, diphtheria). It saw a resurgence in the 1960s when long-term intubation was used as a treatment in neonates in need of prolonged ventilation support.
• If severe, it presents very early on in life with airway obstruction requiring immediate surgical intervention. Moderate cases may present in the first few months of life with biphasic stridor ± respiratory distress during the course of an acute inflammatory process - eg, upper respiratory tract infection (URTI). It resembles croup but symptoms are recurrent and prolonged (>3 days). The child may have a hoarse or weak voice. In mild cases, it may be asymptomatic and is only discovered if there is a need to intubate the child; a smaller than normally expected endotracheal tube needs to be used. A number of these children concurrently suffer from gastro-oesophageal reflux. It may be associated with Down's syndrome.
• Mild cases may resolve spontaneously as the child grows but more severe cases require intervention. Development of upper respiratory symptoms during routine infections can indicate whether a child requires treatment. Sometimes, exercise-induced stridor may also warrant treatment. The options include endoscopic procedures (± laser ablation therapy) or open reconstructive surgery.

Laryngeal webs

• These are fibrotic sheets of tissue representing incomplete canalisation of the larynx during development, usually occurring between the vocal cords.^[4]
• The newborn will present with respiratory distress (paroxysmal dyspnoea ± cyanosis), biphasic stridor and a weak cry where the webs are thick, and similar but less severe symptoms when they are thin or incomplete sheets (may be as little as mild dysphonia). There may be the 'Sail sign' on lateral plain X-rays (persistent tissue between vocal cord and subglottis) but definitive assessment is via rigid laryngoscopy.
• Management ranges from observation in very mild cases to surgery: incision may do for thin webs but excision is required with more substantial ones. Tracheostomy is performed in severe cases.
• Symptomatic webs and successfully treated webs are associated with a normal lifespan in the absence of other complicating factors but there may be chronic hoarseness of the voice.

Laryngeal atresia

This is also known as glottic atresia and is the absence of a laryngeal lumen.^[5]It can occur at any level of the larynx and it represents the most extreme form of laryngeal webs. It is a rare abnormality (50 reported cases). Prenatal diagnosis is imperative (but not always possible) or immediate diagnosis at birth (there is severe distress on clamping the cord) as this is invariably fatal unless tracheostomy is performed at the time of birth. It is often associated with other abnormalities, most commonly pulmonary hyperplasia but also problems in the central nervous, gastrointestinal, urogenital and skeletal systems.

Laryngotracheoesophageal cleft^[5]

This rare, mostly sporadic, midline defect involves the posterior larynx/trachea and the anterior wall of the oesophagus. Mild forms may present with stridor, coughing and cyanotic episodes precipitated by feeding. More extensive clefts are associated with a high mortality rate. It is most commonly associated with cardiac and pulmonary abnormalities but ophthalmic and genitourinary problems are also documented. Mild forms may respond to conservative therapy directed towards minimising reflux (nursing upright, thickened feeds) but more severe forms require surgery, usually endoscopic.

Laryngeal masses

• Subglottal haematomas present between 2-12 months of age with croup-like symptoms of varying severity as well as failure to thrive. Most patients develop respiratory symptoms warranting tracheostomy until the lesion regresses (usually by 5 years). Diagnosis is confirmed by rigid bronchoscopy.
• Laryngoceles are dilated sac-like structures filled with air which may extend through the thyrohyoid membrane. The lesions may be multiple and cause intermittent dyspnoea, worsened by crying. This is one condition where CT may be helpful in the diagnosis.
• Saccular cysts are fluid-filled lesions that are distinct from the laryngeal lumen. They are rare and present with varying degrees of respiratory obstruction and dysphagia. They need to be removed surgically but, if they are large, tracheotomy or intubation may be required at birth. They can recur.
• Lymphangiomas are equally rare, arising from lymphatic vessel malformations. URTIs are particularly prone to increase the size of lymphangiomas and may result in tracheostomy being performed. Laser ablation is carried out in less acute cases.

Other laryngeal abnormalities

There are a number of other congenital laryngeal abnormalities which can be broadly classified into:

Supraglottic abnormalities

• Bifid epiglottis: this is a rare condition presenting with inspiratory stridor, airway obstruction ± episodes of cyanosis associated with feeding.
• Vascular and lymphatic malformations: infants may present with dyspnoea, stridor or feeding difficulties. See 'Haemangiomas and vascular malformations', below, for more details about vascular malformations. Unlike vascular malformations, lymphatic lesions do not regress with age, and require endoscopic laser treatment.
• Anomalous cuneiform cartilages: symptoms mimic laryngomalacia.

Glottic abnormalities

• Congenital High upper Airway Obstruction Syndrome (CHAOS): this is a condition diagnosed on in utero ultrasound and is associated with large echogenic lungs, flattened diaphragms, dilated airways distal to the obstruction and fetal ascites or hydrops.

Subglottic abnormalities

• Vascular and lymphatic malformations: see 'Haemangiomas and vascular malformations', below.

Neck abnormalities

Thyroglossal ducts/cysts

These are masses occurring along the pathway of the thyroid gland as it descends from its site of origin (the foramen caecum at the base of the tongue) to its final position in the neck. If a portion of the duct remains patent, it gives rise to a typical painless, smooth, cystic midline mass. This is usually found somewhere between the isthmus of the thyroid gland and the hyoid cartilage. It may also be situated just above the hyoid cartilage. It can be distinguished from other neck masses as it rises when the patient swallows or protrudes the tongue.

They can occur at any age but most are seen in young patients, between 15 and 30 years of age. They may swell and become painful if inflammation/infection sets in. Any infection has to be resolved before such a mass can be surgically excised. Carcinoma can arise in these but this is rare (<1%).^[6]

Branchial malformations

Neck abnormalities can be traced back to the abnormal development of the branchial apparatus, which makes an appearance in the second week of embryonic life. This apparatus is made up of five pharyngeal arches (confusingly numbered 1-6, the 5th being lost in development) which give rise to muscular, skeletal, neural and vascular structures of the neck. If this complex process is disturbed, a cyst, sinus or fistula will result depending on the degree of development. Abnormalities of a structure in a given arch are likely to affect other derivatives from that same arch (eg, fistulae communicate between structures of the same arch). Evaluations of such abnormalities are carried out in a specialist unit.

Branchial cleft cysts^[7]
The clinical manifestation will depend on the branchial arch of origin:

• First branchial cleft cysts: parotid masses, parotitis or otorrhoea/otalgia if there is a tract with the external auditory canal.
• Second branchial cleft cysts: these typically present spontaneously as a painless, fluctuant mass high in the lateral neck.
• Third branchial cleft cysts: these are found at the anterior edge of the sternocleidomastoid (typically on the left) and are rare. There are reports that these are associated with recurrent acute suppurative thyroiditis of childhood.
• Fourth branchial cleft cysts: present as a left-sided, anterior lesion at the lowest portion of the sternocleidomastoid muscle. They are extremely rare and also reportedly associated with recurrent acute suppurative thyroiditis of childhood.

Thymic abnormalities

Incomplete descent of the thymus into the chest can give rise to thymic cysts along the descent line and thymic cysts can be sequestered along the way so giving rise to ectopic tissue. These cysts can grow, become engorged or bleed, so giving rise to asymptomatic neck lumps, typically in the first decade of life (two thirds are diagnosed at birth). 10% of patients will present with a mass effect dysphagia, dyspnoea, pain, and hoarseness, in which case surgery is warranted. It is worth noting that thymic cysts can manifest themselves in association with a number of other conditions - eg, thyrotoxicosis, aplastic anaemia, Down's syndrome and Hodgkin's lymphoma. Uncommonly, myasthenia gravis can be associated with a thymic cyst neoplasm.

Haemangiomas and vascular malformations^[8]

Haemangiomas are the most common of all congenital abnormalities: the incidence is 0.3-2% at birth (their incidence increases in preterm or low birth-weight babies) and 10% at one year. 20% of affected infants have multiple haemangiomas and in 50% of those with cervicofacial haemangiomas there are associated laryngotracheal lesions.

They can be distinguished from vascular malformations: an haemangioma is a proliferative lesion whereas a vascular malformation is an abnormally formed vessel (distended vessel growth). Thus, whereas an haemangioma regresses after a peak growth period, vascular malformations grow proportionately with the child (although they may expand further following trauma, infection or during periods of hormonal change).

A lesion may be both an haemangioma and a vascular malformation. The most common site of presentation for these lesions is in the scalp, face and neck.

Most haemangiomas continue to grow until the patient is about 2 years of age before beginning to regress - 90% have fully regressed by 5 years of age. Treatment is generally for cosmetic reasons and can involve a number of options, including electrodissection, compression, embolisation, cryotherapy, sclerotherapy, radiation and laser treatment. However, these procedures may produce irreversible cosmetic side-effects in themselves. Dermatological advice and appropriate counselling are important (primum non nocere).

Sternocleidomastoid tumour of infancy

A firm, painless neck mass presenting within first two months of life, more on the right and in males, particularly if born breech. They usually resolve by six months but follow-up and appropriate physiotherapy are important to avoid craniofacial asymmetry (surgery may be indicated where torticollis does not resolve by one year).

Other neck lesions

• A quarter of dermoid cysts occur on the neck. They are midline, painless masses typically found in the submental area. They are distinct from thyroglossal lesions in that they do not elevate on tongue protrusion.
• Cervical teratoma  - often large and diagnosed at birth - and a rare condition in this area of the body.^[9]Maternal polyhydramnios is seen in 18% of the cases of cervical teratomas. They can compromise the airway and the oesophagus, warranting prompt surgical excision. There is a 20% incidence of malignancy arising in these lesions.
• Midline cervical cleft.

Surgical excision/repair is warranted for all these conditions.