Oxygenation failure recalcitrant to increasing positive end-expiratory pressure is a feature of severe coronavirus disease 2019 (COVID-19) pneumonia [1]. A Chinese group used prone positioning to improve oxygenation for intubated patients with severe COVID-19 pneumonia [2]. However, prone positioning in unconscious patients is labour-intensive and is associated with various complications [3, 4]. As the incidence of severe COVID-19 pneumonia worldwide increases rapidly, many countries are also facing the problem of diminishing intensive care resources. Prone positioning ventilation is most used today in intensive care units (ICU) for patients with acute respiratory distress syndrome (ARDS) [5-7] and for prevention of ventilator-induced lung injury [8, 9]. Many mechanisms have been proposed, including relieving the dependent lung regions from the compressive force of the heart's weight [10] or increasing aeration in the originally dorsal lung regions [11]. The overall lung ventilation from dorsal to ventral areas is more homogeneous in the prone position than in the supine position. Prone positioning thus improves oxygenation whilst the other variable, perfusion, remains almost constant in both postures.
We read with interest the research letter by NG et al. [1], which described their experience in prone positioning (PP) for awake patients with coronavirus disease 2019 (COVID-19) pneumonia, and concluded that this manoeuvre could delay or reduce the need for intensive care. We agree that the authors demonstrated safety and feasibility of PP in COVID-19 pneumonia patients. However, we humbly suggest a few crucial points be addressed before drawing conclusions on the efficacy of PP.
An 80-year-old female presented to the Emergency Department with two weeks' duration of dyspnoea, loss of voice and weight loss. She denied fever, night sweats, gastrointestinal or joint symptoms. She also did not have ocular symptoms such as flashes, floaters or visual field defects. Significant medical history included diabetes mellitus, hypertension, hyperlipidaemia, osteoporosis, and early dementia. On arrival, tympanic temperature was 36.8ºC, blood pressure was 87/60mmHg, heart rate was 60/min and oxygen saturation was 98% on room air. Physical examination revealed stony dullness percussion note associated with reduced air entry of the left hemi-thorax. There are no naevi noted on the patient's body or conjunctiva. Chest radiograph showed a complete whiteout of the left hemithorax with mediastinal shift to the contralateral side (Figure 1 Panel A). Computed tomography (CT) scan of the thorax, abdomen and pelvis showed a massive left effusion with mediastinal compression, as well as a gastric fundal mass (Figure 1 Panel B). Bedside thoracostomy drained 1.5 litres of black pleural effusion (Figure 2). Pleural fluid study
Introduction and Importance: We present a case of extensive stage small cell lung cancer presenting as perforated appendicitis secondary to an appendiceal metastasis. This is a rare presentation with only 6 reported cases in the literature. Surgeons must be aware of unusual causes for perforated appendicitis as in our case the prognosis can be dire.
Case Presentation: A 60-year-old man presented with an acute abdomen and septic shock. Computed tomography demonstrated perforated appendicitis and a widespread malignant process initially suspected as colonic origin malignancy. Urgent laparotomy and a subtotal colectomy was performed. Further imaging suggested the malignancy was secondary to a primary lung cancer. Histopathology demonstrated a ruptured small cell neuroendocrine carcinoma in the appendix with TTF1 positive immunohistochemistry. Unfortunately, the patient deteriorated due to respiratory compromise and was palliated on day 6 postoperatively.
Discussion: The appendix is a rare site for metastasis of lung cancer and these metastases usually present as acute perforated appendicitis. Distinguishing the site of the primary tumor can be difficult when there is extensive metastatic disease, and this differentiation relies on immunohistochemistry. In our case the patient was managed surgically, however rapidly deteriorated post operatively from multi-organ metastatic disease. This demonstrates the diagnostic challenges in metastatic small cell lung carcinoma presenting as an acute appendicitis as well as the poor prognosis with advanced disease.
Conclusion: Surgeons should consider a broad differential diagnosis for the cause of acute perforated appendicitis as this can rarely be due to a secondary metastatic deposit from a widespread malignant process.
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