1. Background
In the UK, the incidence of liver abscesses is thought to be 7 per 100,000 population, tending to affect older people with those with co-morbidities. Liver abscesses can be caused by a variety of organisms, including parasites and bacteria [1]. Furthermore, the polymicrobial nature of liver abscesses makes choosing the correct microbial agent of choice difficult [2]. What made this case unique, was that three microorganisms were identified as possible causative agents, including both bacteria and parasites.
This case highlights the difficulties and pitfalls of managing patients with liver abscesses, in terms of identifying a causative organism, opting for the most appropriate management and being aware of the risks associated with treatments of liver abscesses, namely of percutaneous drainage of liver abscesses. Currently, guidelines for managing liver abscesses, including criteria as to whether or not to percutaneously drain liver abscesses, are difficult to find, and this case hopes to highlight the need for developing guidelines for the management of liver abscesses [1].
2. Case Presentation
A 70-year-old gentleman had returned to the UK after having spent a few months in rural Thailand who had been complaining of a week long history of a sore tongue and mouth ulcers, with reduced oral intake. On arrival to a UK airport, his friend found him to be confused, and he was brought to the nearest hospital. It is worth noting at this stage, that he had not complained of abdominal pain, diarrhoea nor shortness of breath.
His past medical history included Parkinson’s Disease and Polymyalgia Rheumatica. His medication history included dopamine replacement and regular oral prednisolone (1 mg once a day). A social history revealed he was a retired engineer, and for the last 10 years of his retirement he had been spending approximately 6 months of each year in rural Thailand. Prior to his hospital admission, he was independent of all activities of daily living.
On examination, his mouth ulcers were noted and he was slightly icteric. Initial blood tests revealed a raised procalcitonin of 49.6 µg/L, a neutrophilia of 25.7 × 109/L and a CRP of 128 mg/L. There was also a cholestatic picture on his blood tests, with a total Bilirubin of 68 µmol/L (conjugated Bilirubin was 50 µmol/L), Alkaline Phosphatase of 263 IU/L, Alanine Aminotransfrase of 13 IU/L, Albumin 13 g/L and INR of 1.4. The blood film suggested toxic features, suggestive of acute infection.
A CT scan revealed multiple peripherally enhancing hypotenuse lesions in the right lower lobe of the liver, the largest measuring 6.5 cm in maximum dimension, suggestive of a liver abscess (see Figure 1). There were also a couple of small well-defined hypotenuse lesions seen in the left lobe of the liver, the larger one measuring 1.5 cm, likely representing hepatic cysts. A subsequent CT scan revealed a small right sided pneumothorax, which was conservatively managed.
Figure 1. Initial CT Abdomen and Pelvis with contrast: multiple peripherally enhancing hypoattenuating lesions in the right lower lobe of the liver, at least 3 of which with a diameter of approximately 3 cm.
Two percutaneous drains were radiologically inserted into the liver in order to drain the liver abscesses. However, soon after insertion of the percutaneous drains, which he became tachycardic and hypotensive, requiring vasopressor support in the intensive care unit. It is likely that he developed septic shock post insertion of the percutaneous drains. He recovered from this over the next few days, being weaned off vasopressor support, and he eventually was stepped down back to a medical ward. The fluid from the hepatic drains grew was pyogenic and grew Streptococcus intermedius, which at the time, was thought to be a contaminant. The hepatic drains were eventually removed once their output was negligible.
Figure 2. Subsequent CT scans: Improving appearance of liver abscesses, some having resolved completely, and one having reduced to 1cm diameter; hepatic drains have been removed by this point.
Amoebic and Hydatid ELISA were negative, the latter excluding Echinococcus Granulosus as a potential cause, however Shistosoma ELISA came back positive. It should be noted the turnaround time for these results was over 10 days, hence the gentleman was covered with antibiotics that covered anaerobic bacteria in the interim, given the liver abscesses. The antibiotics used included amoxicillin and metronidazole, which was well tolerated. The patient had also grown a Prevotella denticola baceteraemia, however because of its fastidious nature, no sensitivities could be provided. Once the ELISA results had come back, on the advice of the microbiology team, Praziquantel had been prescribed, however unintentionally it had been prescribed as a course rather than a single dose. The gentleman developed a wide-spread desquamating skin rash subsequent to this, and Praziquantel was discontinued.
A subsequent CT scan performed just over 2 weeks after the initial CT scan, revealed improving appearances of the liver abscess (see Figure 2). His mouth sores had eventually healed and neutrophil levels and liver function tests eventually normalised. His ability to swallow, however, unfortunately appeared to deteriorate, which was highlighted during video fluoroscopy, despite timely administration of his Parkinson’s medications through an NG tube. It was eventually agreed for risk feed approach and he was discharged to a rehabilitation facility.
3. Discussion
Unlike most bacteria, parasites such as Schistosoma won’t appear on blood cultures. Diagnosis requires requesting specific serology for Shistosoma and other parasites, and therefore requires a high index of suspicion, as it may not be commonly requested. It’s worth noting, however that positive serology in a patient who is native to an area endemic with a parasite may reflect only a past infection unrelated to current clinical condition. These antibodies may be present for months to years, and it should be noted that parasite-specific IgM or IgG antibodies are often not useful either, hence establishing the acuity of an infection may be difficult [3]. Although the gentleman in this case was not native to Thailand, he did spend many years in Thailand in his later life, and although Schistosoma has in the literature been implicated in development of liver abscesses [4], whether the positive serology reflects a previous relatively innocuous infection or whether it reflects a cause of his abscesses is not clear.
There have been reported cases of Prevotella denticola, which is a normal component of the upper respiratory tract, causing liver abscesses, particularly if associated with periodontal disease [5] [6]. Although poor dentition did not appear to be a concern, given the presentation including mouth ulcers and a sore tongue, one may wonder whether it was in fact Prevotella as a causative organism of the abscess rather than Schistosoma.
Streptococcus intermedius, like Prevotella denticola, is a normal component of the upper respiratory tract. There have been reported potential associations of Streptococcus intermedius with liver abscesses [7]. Therefore, another question we have to ask is whether Streptococcus intermiedus grown in this gentleman’s fluid from his hepatic abscesses was indeed a contaminant or a possible causative agent (or potentially one of the causative agents) in this case? Indeed, there is the possibility that the liver abscess in this case was polymicrobial. In fact, a study in USA, examined 20 patients with pyogenic liver abscesses and found 12 of them to have polymicrobial liver abscesses [8].
Liver abscesses are generally either pyogenic or amoebic. Amoebic liver abscesses are caused by the parasite Entamoeba Histolytica, whereas pyogenic liver abscesses are caused by a range of bacteria. Advanced age has been reported to be more of a risk factor for pyogenic liver abscesses than it does for amoebic liver abscesses, where immunosuppression is described in the literature as being more of a risk factor. It is worth noting that the long term use of low dose steroid medication in this case likely had a role to play in lowering the immune system, to predispose this gentleman in developing liver abscesses.
The two different types of liver abscesses (amoebic and pyogenic) are usually clinically and radiologically difficult to distinguish, although pyogenic liver abscesses are more likely to have multiple liver abscesses. Given the relatively advanced age of the gentleman in this case, and the multiple abscesses found on the CT scan, it is likely that he had a pyogenic liver abscess. Given that bacteria are generally the cause of pyogenic liver abscesses, and Prevotella denticola and Streptococcus intermedius were the bacteria that were cultured in this case, it is likely that one or both of these bacteria were potentially the cause of the pyogenic liver abscesses. Certain literature describes the recommended treatment for amoebic liver abscesses as including amebicides (+/− drainage of the abscess), whereas antibiotics with drainage is recommended for pyogenic liver abscesses [2].
The gentleman developed hypotension and tachycardia post insertion of the percutaneous drains, therefore it is possible he had developed septic shock potentially as a result of percutaneous drainage of the liver abscesses. One study, based in USA analysed 27 patients who had hepatic abscesses drained percutaneously. 7 of the patients developed symptoms of “septicaemia” after they were drained, 2 of whom were reported to have died from the post procedure “septicaemia” [9]. Although, there is a huge importance of draining hepatic abscess, the study and the case both highlight the need to be aware of the risks of percutaneously draining liver abscesses.
Another issue, this case highlighted, there is a significant proportion of bacteria that are fastidious, i.e. they are not easily grown on media. This may be due to there not being able to grow on media currently used in practice today or interactions with other bacteria in the environment. This issue means that there may be pathogenic bacteria that may cause abscesses that we are unable to incubate, and therefore unable to identify or treat [10].
The strengths of this case were that there was access to parasitic serology testing as well as interventional radiology to allow drainage and culture of the hepatic abscess. The limitations of this case was this gentleman was managed in a gastroenterology ward at a district general hospital, and not a specialist liver unit in a tertiary centre, where outcomes and prognosis potentially may be different.
4. Conclusion
Nevertheless, we can conclude that clinicians managing patients with hepatic abscesses need to be aware of what investigations to request as well being aware of what management would be most appropriate, especially to be aware of complications from treatments. Given there are no specific guidelines for managing liver abscesses, there needs to be effort to create guidelines to aid clinicians in managing patients suffering from liver abscesses.
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Authors’ Contributions
I am the sole author. I have independently written up the entire manuscript.
Acknowledgements
I would like to thank the patient involved in the case and the rest of the Gastroenterology Department at The Princess Alexandra Hospital.