Vishesh Paul

Epidemiology and outcome of infections with carbapenem-resistant Gram-negative bacteria treated with polymyxin B-based combination therapy

Abstract Introduction: Infections with carbapenem-resistant Gram-negative bacteria (CRGNB) are increasing and are associated with a high mortality. Synergistic effects of combination therapy with a polymyxin, carbapenem, and rifampin have been observed in in vitro studies. Clinical data are limited to retrospective studies. Methods: We performed an observational cohort study of patients over 18 y of age who were treated with polymyxin B combination therapy. Results: One hundred and four patients were studied. The mean age was 77 y; 73% had recently received antibiotics, 67% had recently been hospitalized, and 47% lived in a nursing facility. The most common infections were pneumonia and urinary tract infection due to Acinetobacter baumannii (33%), Klebsiella pneumoniae (24%), and Pseudomonas aeruginosa (11%). Treatment regimens included polymyxin B with a carbapenem in 48%, with additional rifampin in 23%. Clinical success was achieved in 50% and reinfection occurred in 25%. Treatment-related acute renal failure occurred in 14.4%. No treatment-related hemodialysis was needed. All-cause hospital mortality was 47% and mortality after 6 months was 77%. No significant difference was found between treatment regimens. Age (odds ratio (OR) 10.4 per 10 y, p = 0.04), severity of acute illness (OR 2.2 per point, p < 0.001), and Charlson score (OR 1.12 per point, p = 0.04) were associated with hospital mortality. K. pneumoniae was associated with increased hospital survival compared to other CRGNB (p = 0.03). Conclusion: CRGNB infections are associated with previous antibiotic and health care exposure. Mortality is related to age and the severity of chronic and acute illness.

Severe epistaxis after nasogastric tube insertion requiring arterial embolisation

A 53-year-old dialysis patient was admitted with symptoms of a respiratory tract infection, abdominal pain and vomiting. She aspirated and required intubation. A nasogastric tube was placed with slight difficulty and the patient developed severe epistaxis. The bleeding could not be controlled with mechanical pressure and nasal packing. Angiography revealed extravasation from a pseudoaneurysm arising from the inferior pharyngeal branch of the ascending pharyngeal trunk. The vessel was successfully embolised with cessation of bleeding. We emphasise that even a seemingly easy procedure like insertion of a nasogastric tube, can lead to a life-threatening complication.

Acute pulmonary edema secondary to hyperbaric oxygen therapy.

Hyperbaric oxygen therapy (HBOT) has been shown to be effective in the treatment of diabetic ulcers, air embolism, carbon monoxide poisoning and gas gangrene with minimal adverse effects. Very few cases of HBOT causing acute pulmonary edema (PE) has been described; with a study on dogs suggesting that a complication of this therapy could be PE. We describe the case of an 80-year-old man with a history of stable systolic heart failure and diabetes mellitus presenting with acute PE following treatment with HBOT for diabetic foot.

Pneumothorax occurring after nasogastric tube removal

An 85-year-old woman with failure to thrive due to poor oral intake was admitted owing to dehydration. A nasogastric (NG) tube was inserted for the initiation of enteral feedings. The tube position was confirmed by gastric auscultation after insufflating air through the tube. A chest X-ray revealed that the NG tube traversed the right main stem bronchus with its tip ending in the right costophrenic angle adjacent to the pleura. No pneumothorax was identified. The tube was removed and a short while later the patient developed mild chest discomfort. A repeat chest X-ray revealed significant pneumothorax on the right side. She was treated conservatively with 100% oxygen with successful resolution of the pneumothorax.

Severe pneumonitis refractory to steroids following anti-PD-1 immunotherapy.

Anti-programmed death 1 (PD-1) immune checkpoint inhibitors enhance the antitumour activity of the immune system and have produced durable tumour responses in several solid tumours including non-small cell lung cancer (NSCLC). However, PD-1 inhibitors can lead to immune-related adverse events , including pneumonitis, which is typically mild, but can be severe and potentially fatal. Pneumonitis often resolves with steroids, but some cases are steroid refractory, leading to a relapsing and remitting course in milder cases or the need for salvage therapies in more severe cases. Here, we present two patients with NSCLC who developed severe pneumonitis following therapy with nivolumab and pembrolizumab. While one patient improved with steroids and infliximab, the other patient failed to respond to steroids and subsequently died. These cases demonstrate the highly variable presentation and therapeutic responses seen in patients with pneumonitis following anti-PD-1 therapy and illustrate that severe cases can often present refractory to steroid therapy.