Platypnea-Orthodeoxia syndrome (POS) is a rare clinical entity characterized by dyspnea and arterial desaturation while in the upright position. The various pathophysiologic mechanisms leading to POS has puzzled clinicians for years. The hypoxia in POS has been attributed to the mixing of the deoxygenated venous blood with the oxygenated arterial blood via a shunt. The primary mechanisms of POS in these patients can be broadly classified based on intracardiac abnormalities, extracardiac abnormalities and miscellaneous etiologies. A Patent Foramen Ovale (PFO) was the most common reported site of an intracardiac shunt. In addition to PFO, intracardiac shunt leading to POS has been reported from either an Atrial Septal Defect (ASD) or an Atrial Septal Aneurysm (ASA). Most patients with an intracardiac shunt also demonstrated a secondary anatomic or a functional defect. Extracardiac causes of POS included intra-pulmonary arteriovenous malformations and lung parenchymal diseases. A systematic evaluation is necessary to identify the underlying cause and institute an appropriate intervention. We conducted a review of literature and reviewed 239 cases of POS. In this article, we review the etiology and pathophysiology of POS and also summarize the diagnostic algorithms and treatment modalities available for early diagnosis and prompt treatment of patients presenting with symptoms of platypnea and/or orthodeoxia.

Euglycemic DKA thus poses a challenge to physicians, as patients presenting with normal BG levels in ketoacidosis may be overlooked, leading to a delay in appropriate management strategies. In this article, we review all the possible etiologies and the associated pathophysiology of patients presenting with euglycemic DKA. We also discuss the approach to diagnosis and management of such patients. Despite euglycemia, ketoacidosis in diabetic patients remains a medical emergency and must be treated in a quick and appropriate manner.

Pulmonary artery aneurysm is a rare but important entity in the spectrum of pulmonary vascular diseases. The etiologies can be varied and patients can present with non-specific symptoms with the diagnosis being incidental. There is limited consensus regarding the diagnostic criteria and follow-up imaging for patients diagnosed with this entity. Further the management strategies can be variable depending upon underlying disease, etiology, center dependent expertise, and resources available. We review the etiologies, epidemiology, classification, clinical manifestations, and imaging features of pulmonary artery aneurysm. We also review the current management strategies and suggest an algorithmic approach to these patients.

Bronchoscopic interventions are preferred for sampling suspicious pulmonary lesions as they have lower complications and can achieve diagnosis and staging in one single procedure. Limitations in existing guided bronchoscopy platforms has led to developments in robotic assisted technologies. These devices may allow the bronchoscopist to more precisely maneuver the scope and instruments into the periphery of the lungs under direct visualization while also ensuring stability during sampling of the target lesions. These devices have the potential to improve the diagnostic yield in sampling peripheral lung lesions and may play a role in the treatment of non-operable or oligometastatic peripheral tumors using bronchoscopic ablative therapies. In this article, we review the existing robotic bronchoscopy technologies and summarize the available pre-clinical and clinical data supporting their use.

Renal cell carcinoma (RCC) accounts for majority of all primary renal neoplasms. Classic manifestations of RCC include the triad of flank pain, hematuria and a palpable renal mass. Patients with RCC can develop various extra renal manifestations including involvements of the lungs, inferior vena cava, liver and the bones. The pulmonary manifestations of renal cell carcinoma include metastatic disease including endobronchial, pleural, parenchymal or lymph node metastasis, pleural effusion or hemothorax. Pulmonary embolism and tumor embolism is another common manifestation of renal cell carcinoma. RCC is a highly vascular tumor and can cause pulmonary arterio-venous fistulas leading to high output failure. Rarely, RCC can also present with paraneoplastic presentations including cough or bilateral diaphragm paralysis. Drugs used to treat RCC have been associated with drug related pneumonitis and form an important differential diagnosis in patients with RCC on therapy presenting with shortness of breath. In this review we discuss the various pulmonary manifestations of RCC. A high index of suspicion with these presentations can lead to an early diagnosis and assist in instituting an appropriate intervention.