A 13-year-old Girl with Hypercapnic Respiratory Failure

CASE DESCRIPTION

A 13-year-old female, born of nonconsanguineous marriage presented with early morning headache, easy fatigability, and dyspnea on exertion. She had been admitted four times in past 2 years in other hospitals with hypercapnic respiratory failure requiring noninvasive ventilation (NIV). There was no history of chronic cough, sputum, wheeze, or chest pain. There was no history suggestive of recurrent childhood pneumonia, delayed milestones, or poor performance at school. Her family did not report her to have any snoring or witnessed apnea during sleep. Clinical examination revealed a sleepy child with height of 136 cm, weight of 38 kg, and a body mass index (BMI) of 20.5 kg/m². Her vital signs revealed a pulse rate of 68 beats/minute; respiratory rate of 12/minute, and body temperature of 36°C. The arterial blood gas analysis showed pO₂—61 mm Hg, pCO₂—50 mm Hg, HCO₃—29 mmol/L, and pH 7.34 on room air. The complete blood count, organ functions, chest X-ray, thyroid function tests, and serum cortisol levels were also within the normal range. A spirometry, CT chest, CT pulmonary angiography, and maximal inspiratory and expiratory pressure (MIP/MEP) were normal. In further evaluation, her echocardiography, MRI brain with spinal cord, nerve conduction studies, and laryngoscopy were normal.

Polysomnography (PSG) level 1 under transcutaneous CO₂ monitoring (tcpCO₂) was performed (Fig. 1)

The patient was diagnosed as late-onset congenital central hypoventilation syndrome (LO-CCHS).

The patient had hypercapnic respiratory failure in the arterial blood gas analysis, but with a preserved alveolar-arterial gradient suggestive of pure hypoventilation. Hypoventilation is defined as a fall in ventilation leading to rise in pCO₂ by 10 mm Hg in a polysomnography or to a value more than 45 mm Hg,¹ which was documented in our patient using transcutaneous pCO₂ (tcpCO₂) rising from 45 to 65 mm Hg in the PSG. There was no obstructive apnea, hypopnea, or abdominal paradox. There were frequent arousal and prolonged desaturations during sleep with lowest saturation recorded being 65%. The patient had history of multiple past admissions for her hypercapnic respiratory failure but had not undergone a PSG. In absence of any identifiable pulmonary, cardiac, neuromuscular disease, brainstem disorder, chest wall disorder, chronic obstructive pulmonary disease, chronic drug abuse, or obesity hypoventilation, this patient was diagnosed with LO-CCHS. The genetic mutation analysis could not be carried out in view of nonavailability in our hospital and nonaffordability of the patient for the same for paid labs. There was no family history of similar such complaints in siblings and parents of the patient.

DISCUSSION

Late-onset congenital central hypoventilation syndrome is characterized by adequate ventilation while the patient is awake but hypoventilation with preserved respiratory rates and shallow breathing (decreased tidal volume) during sleep.² While asleep, such patients develop progressive hypercapnia and hypoxemia with variable ventilatory sensitivity to both. Gradually, there is progression from nocturnal to diurnal hypoventilation.³

Children with CCHS usually present in infancy with appearance of cyanosis during sleep with no tachypnea or awakening.⁴ Such children require tracheostomy and ventilatory support. Elder children having central alveolar hypoventilation, who can cooperate, can be managed with noninvasive ventilation. Being a lifelong disease, management requires a diligent effort and support on the part of the parents, family members, home health-care personnel, and physicians. Our patient was titrated with NIV using tcpCO₂ as the guide and corrected sleep-induced hypoventilation. With regular use NIV, a daytime pCO₂ of 41 mm Hg was achieved after 4 weeks. The patient’s early-morning headaches and fatigue reduced significantly with no further hospital admission. Her ABG on follow-up showed a pH of 7.412, pCO₂ 41 mm Hg, and pO₂ 79 mm Hg

Our case highlights the importance of timely diagnosis and proper management with NIV for patients with LO-CCHS as this can help to reduce the associated morbidity.⁵

DECLARATION OF PATIENT CONSENT

The authors certify that they have obtained all appropriate patient consent forms. In the form, the patient(s) has/have given his/her/their consent for his/her/their images and other clinical information to be reported in the journal.

The patient understands that his name and initials will not be published and due efforts will be made to conceal his identity, but anonymity cannot be guaranteed.

REFERENCES

1. Brown LK. Hypoventilation syndromes. Clin Chest Med 2010;31(2):249–270. DOI: 10.1016/j.ccm.2010.03.002.

2. Dosier LBM, Vaughn BV, Fan Z. Sleep disorders in childhood neurogenetic disorders. Children (Basel) 2017;4(9):82.

3. Magalhães J, Madureira N, Medeiros R, et al. Late-onset congenital central hypoventilation syndrome and a rare PHOX2B gene mutation. Sleep Breath 2015;19(1):55–60. DOI: 10.1007/s11325-014-0996-7.

4. Gothi D, Joshi JM. Late onset hypoventilation syndrome: is there a spectrum of idiopathic hypoventilation syndromes? Indian J Chest Dis Allied Sci 2005;47(4):293–298.

5. Marcus CL. Sleep-disordered breathing in children. Am J Respir Crit Care Med 2001;164(1):16–30. DOI: 10.1164/ajrccm.164.1.2008171.