Transudative chylothorax and frailty: a diagnostic and therapeutic challenge

Background

Patients with unilateral pleural effusions are frequently admitted to the acute medical take and their presentation is often in the context of multimorbidity and frailty. Patients with non-malignant effusions secondary to organ dysfunction have an estimated 1-year mortality of 25-50%.1 Determining the best approach to their management relies heavily on ascertaining the underlying diagnosis and understanding the pathophysiological processes leading to fluid accumulation.

We report the case of an elderly patient presenting with a unilateral effusion that was unexpectedly found to be a transudative chylothorax. Although only around 14% of chylothoraces2 are estimated to be transudative, they are associated with significant morbidity.

Evidence surrounding the best approach to management of transudative effusions, especially when associated with recurrent or refractory disease, is emerging. Historically, indwelling pleural catheters (IPCs) have been used in the management of patients with non-malignant effusions but a recent randomised controlled trial has demonstrated that their effect on symptoms is not significantly superior to repeated aspiration and is associated with an increased incidence of adverse events3. We present this case with the hope of raising awareness of the complexities of the diagnosis and management of unilateral pleural effusions, and transudative chylothorax in particular, where comorbidities are often significant and case reports are scarce.

Case presentation

A woman in her 90s was admitted to hospital after presenting with sudden-onset breathlessness, worsening chronic cough, leg swelling and a 2-year history of significant weight loss. Her medical history included cryptogenic cirrhosis, aortic stenosis and bronchiectasis. She was a non-smoker with insignificant alcohol intake, with no recent surgery or trauma.

On presentation, she had a respiratory rate of 24 breaths/minute with oxygen saturations of 96% on air. She was haemodynamically stable and afebrile. The physical examination was consistent with a right-sided pleural effusion.

Investigations

A chest X-ray confirmed a right-sided pleural effusion with no significant parenchymal abnormality (figure 1). Inflammatory markers were normal but cardiac and liver enzymes were raised. Bedside ultrasound of the thorax revealed a right-sided non-septated pleural effusion with some echogenicity. One litre of straw-coloured fluid was aspirated, and analysis was consistent with a transudative chylothorax (pH 7.53, cholesterol 0.6 mmol/L, lactate dehydrogenase 130 U/L, triglyceride 2.11 mmol/L, paired serum triglyceride 0.97 mmol/L, protein 13 g/L).

There was no growth on extended culture of the aspirated fluid. Echocardiography confirmed moderate to severe aortic stenosis with biatrial dilatation and dilated aortic root. Systolic function was normal and ejection fraction was preserved at >55%. CT scan of neck, thorax, abdomen and pelvis revealed a non-occlusive portal vein thrombosis, liver appearances consistent with cirrhosis and mesenteric oedema and ascites in addition to the pleural effusion (figure 2). No evidence of malignancy was demonstrated on CT scan and cytological analysis of the pleural fluid was also negative for malignancy.

Differential diagnosis

The unilateral effusion in this patient with aortic stenosis was initially felt secondary to presumed congestive cardiac failure. Once biochemical analysis and echocardiographic evaluation of heart function had been obtained, the transudative chylothorax was then considered in relation to cryptogenic liver cirrhosis.

Treatment

Unfortunately, our patient experienced rapid reaccumulation of fluid causing significant symptoms and requiring two further therapeutic aspirations over a 2-week period. Supplemental oxygen was administered intermittently throughout admission to maintain saturations. The decision was made that transjugular intrahepatic portosystemic shunt was not in our patient’s best interests due to frailty and the extent of her comorbidities. She responded to diuretics and was commenced on a very low-fat diet with one tablespoon of sunflower oil daily to provide essential fatty acids.

Outcome and follow-up

Our patient did unfortunately test positive for COVID-19 later during her stay in the hospital but remained clinically stable, without respiratory consequence. She was discharged with plans to be reviewed in pleural clinic for discussion surrounding IPC insertion. Her condition initially deteriorated shortly after discharge, and IPC insertion was not felt by the respiratory team, the patient or her family to be in her best interests at that point. She remained at home, however, and subsequently, stabilised with improvement in symptoms. Several months later, we are delighted to hear she is doing well and enjoying time with family at home without need for repeated aspiration.