Subglottic concretion masquerading as foreign body in a child with β thalassemia major: an airway nightmare!

Abstract

Subglottic concretion is a rare and perilous condition usually presenting with existing or impending airway obstruction. Due to long-standing nature of the condition, slow progression of symptoms and rarity of occurrence, the condition is either missed or misdiagnosed. Its resemblance in presentation and symptoms to that of foreign body (FB) bronchus can lead to a diagnostic misadventure. Detailed history, chronology of symptoms and radiological imaging in conjunction with fiberoptic evaluation are keys for establishing correct diagnosis. Treatment outcomes in such cases depend on appropriate management approach with backup plan in tandem. We describe a child with β thalassemia major with subglottic concretion, which was erroneously diagnosed and managed as a case of subglottic FB due to its classical history and presentation. The aim is to highlight the circumstances leading to this diagnostic misadventure with emphasis on airway management, problems faced and lessons learnt during the same.

Background

Paediatric airway obstruction is the leading cause of infantile deaths and ranks fourth among mortality in preschool children, of which tracheobronchial foreign bodies (FBs) presents as life-threatening emergency needing urgent bronchoscopy and FB retrieval.¹ Subglottic FB is one such condition that present as an existing or impending airway obstruction with most of the patients having nonspecific symptoms like hoarseness and difficulty in breathing.^{2 3} The diagnosis of such a condition therefore, requires a high degree of suspicion. Laryngoliths or subglottic concretions are similar in presentation as an FB, but rare and life-threatening variant of airway obstruction having grave implications. Subglottic FB has been widely reported; however, only very few cases have been reported regarding laryngoliths or subglottic concretion in children. Stones are usually formed in tubular organs and can occur at many sites inside the body, for example, sialolith, broncholith, rhinolith, tonsillolith, ureteric calculus and so on.^4–9 Since the vocal cords vibrate with fast air stream, and there is a lack of a specific structure on the vocal cords for calcification to develop, formation of a laryngeal stone is very rare. Moreover, unlike subglottic/tracheobronchial FB aspiration, laryngoliths and subglottic concretions do not present with acute airway obstruction. Patients with acute respiratory distress may be forthcoming with history of aspiration, but those with chronically obstructed airway vaguely remember any such episodes or the onset of symptoms, more so in patients where an obstruction is caused by a mass formed in vivo.^{2 10} Another condition with similar presentation is subglottic stenosis that is a well-known complication of trauma or prolonged endotracheal intubation and in rare scenario due to chronic subglottic FB. This further complicates FB removal and airway management during the procedure.^{11 12}

Nevertheless, irrespective of the origin of obstruction whether aspirated FBs, laryngoliths or subglottic growth/concretion, they all are potentially life-threatening conditions, requiring emergent bronchoscopy and removal of the obstructing body. Here, we discuss the diagnosis and airway management of a child with transfusion-dependent β thalassemia major, presenting with progressive respiratory distress of 1 month duration.

Case presentation

Nine-year-old male child weighing 25 kg, third child of a nonconsanguineous marriage, known case of transfusion, dependent β thalassemia major since 8 months of age. One month prior to presentation at our hospital, the child developed breathing difficulty after having breakfast. He was taken to the nearby hospital and was managed conservatively. The child persisted with nonspecific symptoms and was on and off treatment as an outpatient for about a month. However, the child continued to have progressive breathlessness and was referred to our hospital for further evaluation. On arrival, the child was already on O2 with face mask at 5 L/min. He was managed with oxygen and nebulisation and was transfused with 300 mL of Packed Red Blood Cells (PRBC) along with injection furosemide 40 mg because of anaemia (Haemoglobin 6.3 gm/dL). Chest X-ray (figure 1) and 2D echo were largely unremarkable. Since, his breathlessness kept worsening, he was placed on high flow nasal oxygenation (HFNO) (AIRVO2, Fisher & Paykel Healthcare, USA) at 40 L/min at FiO2 0.5, but the patient continued to deteriorate and developed stridor.

Figure 1.

Preoperative X-ray chest.

On examination, he was found to have tachycardia, tachypnoea and oxygen saturation of 94% with HFNO. The child was manifesting inspiratory stridor, with intercostal and subcostal retractions, and use of accessory muscles of respiration. Abdominal examination revealed a grossly distended abdomen with everted umbilicus and massive splenomegaly extending to 18 cm below towards right iliac fossa, and hepatomegaly was palpable up to 4 cm below right costal margin.

Fiberoptic laryngoscopy (FOL) was done, which revealed obstruction at subglottic region resembling FB causing subtotal occlusion of the trachea; however, both vocal cords were mobile (figure 2). With suspicious background of FB aspiration, aggravating respiratory distress and stridor, the decision was taken to conduct a rigid bronchoscopic evaluation and FB removal under general anaesthesia with tracheostomy as backup. The parents of the child were counselled in detail about the procedure and periprocedure complications and written high-risk consent was obtained for the procedure.

Figure 2.

Fiberoptic laryngoscopy view with suspected subglottic foreign body with near total obstruction of the lumen.

The patient was shifted to operation theatre, standard monitoring was attached. The child was premedicated with injection glycopyrollate 0.1 mg intravenously, injection dexamethasone 2.5 mg intravenously, injection fentanyl 25 µg intravenously. Preoxygenation was done with 100% oxygen for 5 min to achieve target fraction of expired oxygen (FeO2) of >90%. Anaesthesia was induced with injection ketamine 30 mg intravenously and sevoflurane by inhalation and after ensuring bag and mask ventilation injection succinylcholine 25 mg intravenously was administered, and then the patient was handed over to the ENT team. On table repeat, FOL was done, which reiterated the earlier FOL findings. Rigid bronchoscopy and FB retrieval were attempted with background oxygenation through HFNO (Flow at 50 L and FiO2 of 1.0). Intermittent ventilation was done using face mask in partially obstructed upper airway. Three attempts were made to remove the FB using rigid bronchoscope in the next 10 min. FB was hard in consistency with smooth margins and broke partially on retrieval attempts but was stuck and could not be removed. Meanwhile the child regained spontaneous ventilation, but ventilating the child became progressively arduous and the child started desaturating. With the airway advancing to complete obstruction salvage endotracheal intubation with small size endotracheal tube (4.5/4.0 mm uncuffed) was attempted, but failed due to the impacted FB and subglottic oedema caused due to multiple retrieval attempts. Immediate decision was made to perform emergency surgical tracheostomy. Tracheostomy posed another challenge as the child had short neck, a large thyroid gland and was secured with 5.0 mm single lumen tube. Unfortunately, patient developed severe hypoxemia-induced pulse less ventricular tachycardia. Cardiopulmonary resucitation (CPR) was initiated as per paediatric advanced life support (PALS) guidelines. Direct current (DC) shock was given first with 50 J and subsequently with 100 J. Injection epinephrine 250 µg was administered two times. Return of spontaneous circulation (ROSC) with sinus rhythm was achieved after the second DC shock. Arterial blood gas analysis done post-ROSC revealed severe acidemia with pH of 6.8, PaO₂ of 57 mm Hg, PaCO₂ of 136 mm Hg and HCO3 of 15. Immediate post-ROSC, heart rate was 140/min, blood pressure was 114/62 mm Hg without any inotropic support. Pupils were 2 mm in diameter, and sluggishly reacting to light. Both lung fields were evaluated by bedside Ultrasonography (USG), which revealed bilateral equal air entry with no fluid in pleura. Transthoracic echocardiography was performed, which showed a normal functioning heart. The urinary bladder of the patient was catheterised. Right femoral vein was cannulated with 7 Fr triple lumen central venous catheter and left femoral arterial line was placed with 20 G arterial catheter. Patient was shifted to the paeditaric intensive care unit (PICU) for postoperative ventilation. The child maintained stable vitals without any inotropic support.

Investigations

Fiberoptic laryngoscopy (video 1).

Video 1.

Download video file ^{(30.7MB, mp4)}

DOI: 10.1136/bcr-2021-242849.video01

Chest X-ray (figures 1 and 3).

Figure 3.

Postoperative X-ray chest showing bilateral nonhomogeneous opacities consistent with pulmonary oedema.

Differential diagnosis

Differential diagnoses include tracheobronchial FB, tracheobronchial tears/injury, bacterial tracheitis, tracheobronchial tuberculosis, retropharyngeal abscess, epiglottitis, acute peritonsillar abscess, laryngotracheobronchitis (croup), retropharyngeal abscess.

Anatomical/mechanical causes include gastric contents aspiration, neck compartment haemorrhage/ haematoma, vocal cord dysfunction. Chronic paediatric conditions leading to airway obstruction could be laryngotracheomalacia, vascular ring (double aortic arch) and paradoxical vocal cord movement.

Outcome and follow-up

After shifting to the PICU, heart rate was 144/min, blood pressure was 140/90 mm Hg, SpO₂ was 97% with FiO2 of 0.8 and respiratory rate was 37/min. The child was placed on ventilator in Pressure controlled-Synchronized intermittent mandatory ventilation (PC-SIMV) mode P_insp of 18 cm H₂O, Positive end expiratory pressure (PEEP) of 6 cm H₂O, Respiratory rate (RR) 40/min and FiO2 of 1.0. Arterial blood gas (ABG) was done, which revealed pH of 7.088, PaO₂ of 57.6 mm Hg, PaCO₂ of 80.05 mm Hg and HCO_3- of 23.5 mEq/L. Injection norepinephrine infusion was started at 0.1 µg/kg/min and titrated to keep mean arterial pressure >50th percentile. Regular tracheal suctioning was done, and frequently blood tinged aspirate was suctioned out. With the background of spontaneous respiration against obstructed airway during the procedure, normal echocardiography and chronology of events leading to the current clinical picture, probability of negative pressure pulmonary oedema was high. Chest X-ray was performed in supine position, which also corroborated with the clinical picture and revealed features suggestive of pulmonary oedema (figure 3). In PICU, the child remained severely acidotic with progressively worsening ventilatory and haemodynamic parameters. Eight hours after shifting to PICU, the child developed progressive desaturation with bradycardia. CPR was started with chest compressions and tracheostomy tube ventilation. CPR continued as per PALS protocol with three injections epinephrine (1:10000) intravenously at 10 μg/kg. No pulse was palpable, nor any spontaneous respiratory efforts were seen. After 45 min of CPR, no electrical activity was observed on ECG. Subsequently, the child was declared dead. An autopsy was critical for establishing definitive diagnosis, but parents declined permission. Histopathology of the retrieved pieces revealed hyperplastic stratified squamous epithelium, which is focally ulcerated and ulcer bed is covered with granulation tissue suggestive of chronic nonspecific inflammation (figure 4).

Figure 4.

Haematoxylin & Eosin (H&E) and Periodic acid-Schiff (PAS) stain photomicrographs. (A and B): Section shows a fragment lined by hyperplastic stratified squamous epithelium, which is focally ulcerated and ulcer bed is covered with granulation tissue (H&E stain, 20×). (C) Section shows mixed inflammatory infiltrate and proliferating capillaries (H&E, 40×). (D): PAS stain did not highlight any fungal profiles (PAS stain, 20×).

Discussion

Subglottic airway obstruction mostly occurs in children in the age group of 1–3 years. The reported incidence of laryngeal lodgment of aspirated FB varies from 2% to 11%.^{1 13} However, clinical reports of laryngoliths/subglottic concretions have been exceedingly rare. The formation of stone occurs in the respiratory tract in similar way, as they form in other parts of the body, like nose, tonsils, ureter, gall bladder and so on. However, the larynx does not provide a suitable environment for stone formation, as it is a dynamic structure, and due to the fact, that, the vocal cords constantly vibrate, with a fast airflow going past it during vocalisation. Moreover, the sub-glottis and the trachea are relative wider passages, with constant airflow during breathing. Finally, there is no medium or nucleus over which calcification might begin, for stone formation.

Moersch and Schmidt enumerated three different pathological processes for the formation of stones in the airway.¹⁴ First, stones may develop within the lumen of the bronchus subsequent to the deposit of calcium about a FB nucleus. Second, stones may occur as a consequence of calcification or ossification of the elastic cartilage of the bronchus with subsequent sequestration of the calcified material into the bronchial lumen. Finally and most commonly, most occur as the result of erosion and protrusion of calcified hilar and paratracheal nodes into the tracheobronchial tree. A fourth mechanism mentioned is inspissation of mucus, with further fibrin formation and calcification.

The first such case report was made by Baker and Karlan, wherein he described a 66-year-old woman who presented with dysphonia, with no dysphagia or stridor.¹⁵ Three years later, the patient developed stridor, dysphonia and shortness of breath. Initially, she underwent emergency tracheostomy, and, subsequently, she was found to have a calcified mass in anterior commissure under direct laryngoscopy, which was then removed. They postulated that the patient developed extensive ossification of her laryngeal cartilages postradiotherapy. Furthermore, mucosal insult by laryngeal instrumentation and biopsy might have led to low-grade infection and resultant chondronecrosis. The patient then developed laryngeal stricture, sequestration of ossified cartilage into the lumen and further accumulation of inspissated mucus around the mass with additional calcification, leading to the formation of laryngoliths. Hegab et al described a 44-year-old woman who presented with laryngeal stridor and incapacitating dyspnoea unresponsive to medical treatment.¹⁶ Direct laryngoscopy revealed two lesions projecting from the posterior cricoid lamina and an anterior subglottic soft tissue mass. Laryngeal litholopaxy was conducted and both the masses were removed. They proposed that trauma from endotracheal tube led to granuloma formation, which subsequently ran an indolent course over many years and calcified forming a laryngoliths.

Nam and Cho described a 50-year-old woman who presented a laryngeal mass in right subglottic area.¹⁷ Histopathology of the excised tissue reported amorphous stones of unknown components. They hypothesised that the patient’s laryngeal stone could have been caused by trauma due to endotracheal intubation 30 years prior.

Our patient was a case of transfusion-dependent beta thalassemia major. Patients with myeloproliferative disorders as well as those suffering from haemoglobinopathies exhibit extramedullary haematopoiesis (EMH). EMH is a well-documented pathophysiology in thalassemia with haematopoietic cell colonies breeching the bony cortex and even form masses of extramedullary haematopoietic material in the certain susceptible areas like thoracic or pelvic cavities as well as other anatomic regions. These, in turn, can cause a mass effect in their respective anatomical location, thus causing damage to adjacent structures, such as spinal cord compression and vascular occlusions, and may exhibit signs and symptoms accordingly. Barnes et al described a 70-year-old woman, a known case of polycythaemia vera with postpolycythaemia myeloid metaplasia who presented with progressive shortness of breath for 3 months.¹⁸ FOL revealed bilaterally soft tissue masses arising from the lateral subglottic walls causing airway obstruction. The patient underwent tracheostomy followed by submucosal biopsy revealing EMH on histopathology.

In our case, it is possible that the child could have developed EMH in cartilages in subglottic area, calcification of such cartilage and erosion of the subglottic mucosa and protrusion of the cartilage into the subglottis. This could have been further complicated by inspissation of the mucosa because of the fast air movement around the subglottic mass and concretions of epithelium, inflammatory cells mimicking a FB leading to subtotal occlusion of the subglottis. A planned tracheostomy prior to attempting rigid bronchoscopy and FB retrieval could have been done but was not contemplated due to ability to ventilate adequately in the beginning of case and progression to total obstruction was not considered in high probability. Unfortunately, during the retrieval attempt/handling of the FB/laryngoliths, it progressed to total obstruction leading to Cannot Intubate Cannot Oxygenate CICO scenario. However, in retrospect irrespective of the cause of obstruction, that is, subglottic FB or laryngolith, an emergency tracheostomy would have been a safer option and should have been contemplated especially when the FOL showed near-total obstruction.

Learning points.

• All cases of subglottic obstruction should undergo anterior and lateral view X-ray neck as well as CT wherever possible to identify the location and nature of obstruction.

• Subglottic airway obstruction is an acute emergency and should be dealt as such with emergent rigid bronchoscopy.

• Prior to induction of anaesthesia for instrumentation, the patient’s airway should be evaluated in a detailed manner, and with difficult airway being anticipated, a difficult airway cart should be kept on stand-by including front of the neck access.

• Patient should be adequately preoxygenated prior to induction of anaesthesia and, wherever possible, should be placed on high flow nasal oxygen or jet ventilation during periods of apnoea, during which instrumentation of the airway will be done.

• Finally, pre-emptive tracheostomy should be contemplated as a first choice in select cases like ours where risk of losing the airway is eminent because of progression to compete obstruction.

Ethics statements

Patient consent for publication

Parents/Guardians consent obtained.