Rapidly enlarging, giant hepatic cyst growing pseudomonas

Abstract

A 74-year-old woman presented with dyspnoea and fever on a background of a large hepatic cyst thought to be stable in size. During her admission, she developed worsening shortness of breath. An echocardiogram revealed severely impaired cardiac output due to external compression by the hepatic cyst, which had grown rapidly. This was drained under ultrasound guidance and cultures of this fluid grew Pseudomonas aeruginosa: the organism responsible for the persistence of this giant hepatic cyst.

Background

Asymptomatic hepatic cysts occur in approximately 5% of the population.¹ A small proportion may expand causing obstruction of the gallbladder and other local organs, often associated with non-specific symptoms.² Rarely, hepatic cysts may become exceptionally large, impacting organs far beyond their origin.³ We present a case not yet seen in the literature, identifying a rapidly enlarging giant hepatic cyst growing Pseudomonas aeruginosa.

Case presentation

A 74-year-old woman presented with fever and worsening dyspnoea for 1 week, on a background of intermittent dyspnoea for 2 years. The patient had a known hepatic cyst under surveillance at a different tertiary centre, which had been stable in size over a period of 1 year. The patient’s medical history included lymphoedema, chronic kidney disease and previous transient ischaemic attacks. Prior to admission, the patient was independent and managed normal daily activities. On examination, there was bilateral pitting oedema to just above both knees and significant unilateral leg erythema. Reduced breath sounds on the right side, and a palpable liver with an undefined edge.

The patient was admitted to the hospital and commenced on intravenous co-amoxiclav for severe cellulitis, a probable cause of her fever. Initially, with the exception of fever, the patient had stable observations: maintaining a systolic blood pressure of 120 mm Hg with a normal heart rate, oxygen saturation of 94% on 1 L O₂, and a mildly elevated respiratory rate (20–24 breaths per minute). Table 1 shows laboratory blood results on admission. Acute kidney injury was also noted. On day 4 of admission, the patient’s systolic blood pressure began to trend downwards to between 90 and 100 mm Hg, accompanied by mild tachycardia (90–110 beats per minute) and worsening shortness of breath, though her fever had resolved and respiratory rate was stable.

Table 1.

Admission laboratory results

Component	Value	Reference range
Haemoglobin, g/L	111	115–165
White cell count, ×109/L	8.4	4–11
Platelets, ×109/L	245	150–450
Sodium, mmol/L	135	133–146
Potassium, mmol/L	3.6	3.5–5.3
Urea, mmol/L	15.6	2.5–6.5
Creatinine, μmol/L	243 (patient baseline approx. 120)	45–84
Estimate glomerular filtration rate, mL/min	17	>90
C-reactive protein, mg/L	22	0–5
International normalised ratio	1	<1.1
Activated partial thromboplastin time, s	45	25–50
D-dimer, ng/mL	1050	<250 (considered negative)

Chest X-ray showed a raised right hemidiaphragm, but no consolidation or effusion. An urgent echocardiogram showed compression of the right heart chambers by her giant hepatic cyst, resulting in severe cardiac output impairment. A CT scan revealed three large hepatic cysts. There were no signs of cyst infection on the CT scan. The largest cyst appeared to occupy a significant portion of the right hemithorax, measuring 33 cm in the largest longitudinal measurement and 17 cm in the largest lateral axis, with additional cysts in the midline (8×8 cm) and on the left (15×11 cm). A comparison with previous scans showed that the largest cyst had grown by over 6×2 cm in <1 year (see figure 1, right hepatic cyst comparison based on two dimensions).

Figure 1.

Pre-drainage sagittal and coronal non-contrast CT slice demonstrating three large cysts and associated visceral displacement. Soft tissue window.

Further investigations and management

An opinion was sought from the hepatopancreaticobiliary team at a tertiary centre for possible surgical management where patient’s suitability for transfer raised the question mark and it was deemed not appropriate. A local multidisciplinary team made recommendation of ultrasound-guided drainage of cysts in the intensive care setting. Over a period of 10 days, three 7.5 French Pigtail drains (Hydrophilic-coated ReSolve) were inserted into the cysts according to the Seldinger technique utilising CT guidance. The Pigtail catheters inserted were ReSolve Hydrophilic-Coated 7.5 French (25 cm/0.038’) Locking Drainage Catheter (Merit Medical, Merit Parkway, South Jordan, Utah, USA).

During this time, the patient also became septic and required inotropic support in the critical care unit. While on Intensive Treatment Unit (ITU), multiple drains were put in place at different time points. This was due to the presence of multiple septated non-communicating cysts of different sizes being present. These cysts were not amenable to synchronised drainage as the patient could not be comfortably positioned in ITU if multiple drains were placed in situ at one time. The patient was treated with flucloxacillin and clindamycin as per advice from the local microbiology team. Two days after drainage of the first cyst, initial fluid cultures showed gram-negative rods, identified as P. aeruginosa. Antibiotics were changed to tazobactam, piperacillin and metronidazole as per sensitivities. Over a period of approximately 6 weeks, a total of 32 L were drained from the largest cyst. Figure 2 demonstrates the volumes of fluids drained from the three cysts.

Figure 2.

Demonstrates size reduction of the liver cysts.

Outcome and follow-up

The patient had serial CT imaging demonstrating a significant improvement in the size of the largest cyst. Over 42 days, the right cyst reduced in size to 21 cm in height by 14 cm in width. The midline cyst was stable in size at 11 cm × 9 cm, while the left cyst completely disappeared. Unfortunately, due in part to poor mobility, the patient developed a grade 3 sacral pressure sore, and eventually gas gangrene. The patient continued to deteriorate and died secondary to gas gangrene associated-sepsis.

Discussion

Aetiology of infection

We present a rare case of a rapidly expanding giant hepatic cyst, secondary to Pseudomonas infection. Cases have been described of tuberculosis and echinoccocal-associated cysts, but not of giant Pseudomonas cysts.^{4 5} The aetiology of infected hepatic cyst is not well documented. There is however some literature describing ruptured hydatid cysts leading to pseudomonas sepsis, with no aetiological hypotheses.⁶ Infection of hepatic cysts has been described to occur via the common bile duct (CBD) leading colonisation by enteric organisms such as Escherichia coli, Clostridium or even Pseudomonas.⁷ These infections are rare and are hypothesised to be associated with immunosuppressive states such as chronic haemodialysis or diabetes mellitus—none of which were present in our patient.⁸ There is however some literature describing pyogenic liver abscesses secondary to Pseudomonas, suggesting that the CBD route of infection is most likely in this case.⁹

Identification of infected hepatic cysts

Giant hepatic cysts are most commonly identified incidentally through varying abdominal imaging modalities—MRI, CT and ultrasound.¹⁰ However, if clinical findings and serum samples indicate the presence of sepsis, it is important to consider the infection of hepatic cysts as a potential source.¹⁰ CT scan with contrast may help by showing signs of infection—peripheral enhancement and pericystic oedema. It was not possible to inject contrast in our patient’s case due to poor renal functions (low glomerular filtration rate). Ga67 scintigraphic study and 18-F-fluorodeoxyglucose–positron emission tomography have shown promising results to identify cyst infection, but none of these were available during our case. It can also be investigated using an ultrasound-guided sampling of the cysts for culture and microscopy.¹⁰

Management of giant hepatic cysts

Traditionally, giant hepatic cysts are managed by laparoscopic surgical de-roofing to achieve definitive treatment with a lower risk of recurrence.¹¹ When cysts become large enough to risk cardiac circulation, they should be urgently drained with a view to surgical de-roofing, to prevent the level of cardiac compromise that developed in our case. There have been recent developments in the management of cysts, and recently, single-incision enucleation of the cysts via endoscopy has been shown to have a low level of recurrence in treating hydatid cysts.¹² Other authors have described success when treating giant hepatic cysts with ultrasound-guided endoscopic drainage.¹³

Our patient experienced persistent hypotension requiring inotropic support. This is due to the external compression of the right atrium and inferior vena cava decreasing venous return to the heart and impairing cardiac output this can persist until sufficient drainage of the cyst is achieved to increase venous return. In our case, the cardiac compromise caused by the cyst resulted in the patient being unfit for surgical intervention, preventing definitive intervention. This demonstrates the importance of early intervention in giant hepatic cysts to prevent haemodynamic compromise and the need for emergency interventions.

Learning points.

• In a patient with known hepatic cysts, a diagnosis of infected cysts should be considered if clinical presentation suggests infection with no clear alternate source.

• As these cysts can cause life-threatening haemodynamic instability due to the combination of direct cardiac compression and fluid shift, early multidisciplinary discussions and expert centre advice lie at the centre of whole management.

• CT scans using intravenous contrast agents should be the first-line imaging studies performed, because of high availability and typical diagnostic findings. Alternatively, Ga67 scintigraphic study and 18-F-fluorodeoxyglucose – positron emission tomography could be utilised to identify infected cysts, if available.

• Radiological guided drainage of giant hepatic cysts is a relatively safe approach, bridging the gap between emergency situations and definitive surgical management.