A 54-year-old woman with severe gallstone pancreatitis is reviewed after 2 days of worsening condition, now requiring oxygen. She received 4L IV fluids over 48 hours for nausea and vomiting, with examination findings showing intravascular depletion of fluid.


She has no known cardiac history


On examination her respiratory rate is 35, peripheral oxygen saturations 94% on 10L (40%) Venturi mask, heart rate 115, blood pressure 105/58, temperature 35.6°C.

Respiratory exam reveals diffuse bilateral coarse crepitations and reduced bibasal air entry. Mild pedal oedema extends to the knees. Abdominal exam shows epigastric guarding with mild distension; her abdomen is otherwise soft and non-tender.

Portable chest x-ray is shown below

Which of the following is the most likely diagnosis?

Options:
explanation: Severe pneumonia can present within 48hrs and can be precipitated by poor inspiratory effort from abdominal pain, resulting in mucous plugging, atelectasis, and poor clearing of secretions. Often to develop into fulminant chest sepsis, the patient either has an acute precipitant e.g. aspiration, is immunosuppressed, or has poor residual lung function. This patient does not have evidence of these from the information above and so pneumonia would be a less likely cause of rapid respiratory deterioration in a patient with pancreatitis. The patient's chest x-ray shows interstitial fluid from pulmonary oedema and small bilateral pleural effusions, providing further evidence of acute respiratory distress syndrome over pneumonia
name: Severe bilateral lobar pneumonia
label: c
answer: no
explanation: The patient has signs and symptoms of acute pulmonary oedema. Differentiating between cardiogenic and non-cardiogenic pulmonary oedema can be challenging, although the patient's history, cardiac history, fluid balance, and echocardiography signs can provide useful information. This patient has no cardiac history and has only been resuscitated with 2L intravenous fluid per day for two days with only mild pedal oedema on examination. It is unlikely that the pulmonary oedema is cardiogenic based on this information, and given the history of acute pancreatitis, acute respiratory distress syndrome is more likely
name: Fat embolism syndrome
label: d
answer: no
explanation: The patient has signs and symptoms of acute pulmonary oedema. Differentiating between cardiogenic and non-cardiogenic pulmonary oedema can be challenging, although the patient's history, cardiac history, fluid balance, and echocardiography signs can provide useful information. This patient has no cardiac history and has only been resuscitated with 2L intravenous fluid per day for two days with only mild pedal oedema on examination. It is unlikely that the pulmonary oedema is cardiogenic based on this information, and given the history of acute pancreatitis, acute respiratory distress syndrome is more likely
name: Acute cardiogenic pulmonary oedema
label: b
answer: no
explanation: Acute interstitial pneumonitis (AIP) presents as acute respiratory distress and is the only acute form of idiopathic interstitial pneumonitis. It has a similar presentation and chest x-ray appearance as ARDS due to extensive diffuse alveolar damage. It usually occurs following a prodromal viral upper respiratory tract infection and then 1-2 weeks later rapidly progresses into respiratory failure. It is a very rare disease, not associated with pancreatitis, and is therefore a less likely cause of this patient's deterioration than ARDS
name: Acute interstitial pneumonitis (Hamman-Rich syndrome)
label: e
answer: no
explanation: This patient has presented with an acute respiratory deterioration on a background of acute pancreatitis. Examination findings and chest x-ray point to pulmonary oedema as the likely cause. The patient has no cardiac history and has been resuscitated with 2L intravenous fluid per day. It is unlikely that the pulmonary oedema is cardiogenic based on this (although is common as patients with pancreatitis are often given aggressive fluid resuscitation). The most likely cause of this patients rapid deterioration and new florid pulmonary oedema is acute respiratory distress syndrome (ARDS) secondary to acute pancreatitis. The patient will likely be in the initial exudative phase of ARDS, characterised by diffuse alveolar damage, microvascular injury, type I pneumocyte necrosis, and influx of inflammatory cells. The mechanism of this is likely a consequence of systemic inflammatory response with increased endothelial and epithelial barrier permeability, resulting in leakage of protein-rich substances into the alveolar space and interstitial tissues. Increased cytokines and chemokines result in increased pulmonary infiltration of neutrophils into the interstitial tissue where they cause breakdown of pulmonary parenchyma
name: Acute respiratory distress syndrome
label: a
answer: yes

Correct answer: a

Acute respiratory distress syndrome