CASE PRESENTATION
A 14-year-old boy, previously fit and healthy, presented to his local hospital in March 2020 with rapidly developing respiratory symptoms of breathlessness, cough, and fever over 24 hours post smoking Midwakh, mixed with crushed Damas tree leaves (Conocarpus Lancifolius). On admission, he underwent a series of investigations including COVID 19; started on empirical broad-spectrum antibiotics and oseltamivir, and underwent a high-resolution computerized tomogram of the chest (HRCT), which demonstrated interstitial pneumonia with patchy consolidation and ground-glass appearance (figure 1). Within a few hours, he required intubation and mechanical ventilation due to significant hypoxia.
On day four of mechanical ventilation, he was transferred to our center on Volume control-Assist control settings (FiO2 40 - 70 %, PEEP 8, Tidal volume 400 ml). Initial arterial blood gas upon admission revealed relative hypoxemia (PaO2 77.9, PCO2 42.3 mm Hg). The patient met the criteria for moderately severe ARDS (Bilateral infiltrates on radiographs, PaO2/FiO2 ratio 192 mm Hg (<200) on PEEP 8 and no cardiogenic cause). He was managed with ultra-short lung-protective ventilation (Tv ~5 ml/kg), given poor lung compliance. Neuromuscular blockage and sedation were administered. Auscultation of the chest revealed bilateral decreased air entry and crackles. Continuous infusion of low dose furosemide was commenced for a positive cumulative fluid balance of 4 liters. During his admission, regular chest physiotherapy was performed.
Flexible bronchoscopy was performed on day 5, which revealed severe bilateral inflammation, petechial hemorrhages, and erythematous bronchial walls beside mild increase of airway secretions, in keeping with fulminant lung injury. Bronchoalveolar lavage had negative microbiology culture, viral PCR including the COVID-19 PCR and cell count differentiation of 71 % neutrophils, 5 % Lymphocytes, 6% monocytes, 18% macrophages, and no eosinophils. A diagnosis of interstitial pneumonitis with ARDS due to inhaled toxins was considered, for which the patient was commenced on a five day course of the following anti-inflammatory medications; intravenous Methyl Prednisolone one gram/day (15 mg/kg/day), oral hydroxychloroquine (300 mg per day) and oral azithromycin (500 mg per day). During the PICU admission course, he developed hypertension and pre-renal failure for which anti-hypertensive medications were administered, and diuretics were discontinued. The patient was rehydrated following this episode, balancing the perfusion of his kidneys and lungs. Antibiotics were rationalized because of negative microbiology results. On day 10, high-pressure ventilation was still required despite the high dosage of methylprednisolone. A repeat chest HRCT scan (figure 2) was performed, which revealed left lower lobe consolidation and right lower lobe collapse and the interstitial lung changes with ground glass appearances. Subsequently, a prolonged period of prone ventilation was initiated, after which there was a significant improvement of the ventilator requirements until extubation on day 14. Spirometry was done five days post-extubation and revealed a restrictive ventilatory pattern with forced vital capacity (FVC), Forced expiratory volume in one second (FEV1), and FEV1/FVC being 2.15 L (46.8 %), 2.02 L (53.3%) and 94.09 % (112.8 %) respectively. A minimal global weakness, features of critical illness myopathy and peripheral neuropathy were noted. The patient was discharged on a tapering dose of Prednisone.
Follow up at three months post-discharge showed significant recovery with resolving respiratory symptoms and improving effort tolerance. A follow-up HRCT Chest (figure 3) at three months post-discharge was normal, Spirometry has significantly improved with FVC of 3.8 L (91% predicted), FEV1 of 3.1 L (89% predicted), slightly reduced Diffusion capacity (DLCO) of 6.3 L (70% predicted) and normal 6 min walk test was obtained (with a heart rate of 110 bpm before a walk and 121 bpm after. Oxygen saturation (SpO2) of 100% before the walk and 98% after).