*Corresponding author:Wilson Laffita Labañino, General Surgeon, Master of Emergency Medicine, Medical and Surgical Department of Investigation in Angola, Multiperfil Clinic, 21 Janeiro, Morro Bento, Luanda, Angola
How to cite this article:Wilson L L, Márcio T d C G, Cándido S A L, Lynda D G C, Maria d N I P J. Invasive Klebsiella Pneumoniae Liver Abscess
Syndrome. Analysis of Three Cases in Angola.Adv Res Gastroentero Hepatol, 2021; 17(5): 555975. DOI: 10.19080/ARGH.2021.17.555975.
Liver abscess is a disease that is defined as collection bordered by a fibrotic capsule in the hepatic parenchyma and its frequency and etiology varies according to its geographic latitude. Klebsiella pneumoniae (Kp) was described for the first time in Taiwan in 1980 and it rapidly spread through the east Asia. Due to migration of people from those countries to all the continents today there are cases in Europe, North America, South America and Australia. There is an especially virulent Kp serotype that causes a syndrome with high mortality rate due to its extrahepatic complications known as Hypervirulent Invasive Klebsiella pneumoniae Syndrome (HIKPS). We describe three patients with HIKPS, there are no similar cases known in Angola but in the African continent cases were reported in South Africa, Nigeria and Morocco. The Hypervirulent Invasive Kp Syndrome is a reality in Angola, generally associated to cryptogenic origin and diabetic patients, and is characterized by bacteremia with metastatic infection and even with an adequate treatment, it has a high morbidity and mortality rate. Initially its diagnosis can go unnoticed so a high index of clinical suspicion for an early diagnosis and management is important.
Liver abscess is a disease that is defined as collection bordered by a fibrotic capsule in the hepatic parenchyma and its frequency and etiology varies according to its geographic latitude [1-3]. Generally, they are classified into two groups, pyogenic and amebic, but there are other etiologies such as Mycobacterium tuberculosis [4,5], fungal and parasites . The etiology of pyogenic liver abscess has changed in the last few years due to scientific and technical advancements and strong antibiotics; Intraabdominal infection (appendicitis, diverticulitis) via portal vein used to be the most common cause in the last century but nowadays it was replaced by biliary tract infection in the last decades of the twentieth century [1-5].
First world countries report as a primary cause the biliary tract instrumentation (ERCP), reconstructive biliary surgery, hepatic transplant, treatment of liver tumor, interventional radiology (chemoembolization) and radio ablation [1,5-8]. In Asia, the cryptogenic cause (apparently without etiological cause) is predominant, and in countries of Eastern Asia especially in Taiwan, the Klebsiella pneumoniae (Kp) substitutes the Escherichia Coli as the agent responsible of the formation of the pyogenic liver abscess in the last three decades [1-8]. Kp was described in Taiwan for the first time in 1980 and it rapidly spread through all east Asia reporting 23% in China, 52% in Hong Kong, 72% in South Korea . As a result of the vast migration of people from those countries to all the continents, in nowadays series and isolated cases are reported in Europe, North America, South America and Australia [1-9].
There is a specific Kp virulent serotype that causes a syndrome with high mortality rate due to its extra-hepatic septic complications known as Hypervirulent Invasive liver Abscess Syndrome with bacteremia, metastatic infection, peculiar
ultrasound and Computed Tomography (CT) findings that are
associated to its cryptogenic cause and diabetic patients [1-10].
Three cases with the invasive liver abscess syndrome associated
to Kp were reported in our institution, we don´t have knowledge
of other similar cases reported in Angola but there were cases
reported in other African countries such as South Africa ,
Nigeria  and Morocco .
The aim of the authors is to alert the medical community in
the country and the rest of Africa about this dangerous syndrome
responsible of high mortality rate.
On table 1, described three patients with HIKPS, all Angolans,
without travel background to Asian countries, all male between the
ages of 39 and 65. Two of them were diabetic, the microbiological
agent found was Klebsiella specie (Ksp), one of them was positive
to Kp in the blood culture and pus culture collected from the liver abscess.
The three patients had clinically and radiologically the HIKPS,
characterized by bacteremia, metastatic infection, peculiar
ultrasound and tomography characteristics which are going to be
explained next. From the imaging point of view (ultrasound and
abdominal tomography with contrast): the wall or capsule were
poorly demarcated, were single, multilocular and with presence
of gas in all patients. We could also prove distant metastasis
(tomography diagnosis) in the three patients, been the most
frequents in the lung, mediastinum, muscle groups, bone and
brain as well as the hepatic and portal vein thrombophlebitis.
One patient presented septic pulmonary thromboembolism,
there was not rupture of the abscess into the abdominal cavity.
The therapeutic used was the ultrasound guided percutaneous
drainage and there was the necessity to evolve to a laparotomy in
two of them. All patients evolved to multiple organ failure that led
to their death.
Source: Patients clinical history. Multiperfil Clinic. Luanda. Angola.
Klebsiella pneumonia is a bacillar, Gram-negative bacteria,
facultative anaerobic, non-motile and encapsulated, widely spread through the environment and it grows in mammals’ mucous
surfaces; in human beings it colonizes the nasopharynx and the
gastrointestinal tract . Klebsiella pneumonia is responsible for
the infections of a variety of systems such as respiratory, urinary and digestive, surgical site infections, cholangitis and peritonitis
, generally associated to patients with medical history of
alcohol abuse and diabetes .
In the majority of cases, pyogenic abscesses are polymicrobial
and the Escherichia coli is the most frequent agent [16,17] and
they respond well to a combined treatment of drainage with
antibiotics. In the last century, mid ´80s, pyogenic liver abscesses
caused by specific hypervirulent Klebsiella pneumoniae strains
appeared as an important epidemiologic problem in East Asia
and nowadays they constitute the cause of more than 80% of the
pyogenic liver abscesses in Asia [17,18]. In the last decade, cases
of hypervirulent Klebsiella pneumoniae pyogenic liver abscesses
were notified in the whole world [1-18] regardless of its Asian
origin like in the three patients described in our study in which
all of them were Angolans without travel background to those
Typically, Kp pneumoniae is responsible for the severe
cryptogenic liver abscesses frequently associated to uncommon
distant septic metastatic locations: endophthalmitis, meningitis,
myositis, osteomyelitis among others in immunocompetent hosts
[16,19]. Several studies have been demonstrating that the invasive
Kp strains infect the liver through the portal circulation starting
from the bacterial translocation of the intestinal epithelium
[14,18-20]. It is interesting to comment that the studied patients
has as a past medical history malaria by falciparum 30 days before
the liver abscess diagnosis and according to studies made in rats
by Denny and cols , infection by plasmodium have different
effects on the homeostasis of the intestinal microbiota that could
contribute to a enteric bacteremia associated to malaria.
Diabetes mellitus is considered as a risk factor for Kp liver
abscess and its complications, it is proposed that hyperglycemia
interferes in the polymorphs leukocytes chemotaxis and therefore
compromises the phagocytosis of the K1 and K2 encapsulated serotypes that are considered as hypervirulent strains  and it
is related to a bad control of these patients glycemia as a possible
cause of the metastatic septic complications [14,21].
In relation to the etiology, Kp liver abscesses rarely have a
biliary, portal, pos surgical, traumatic, or tumoral cause, generally
they have a cryptogenic cause. Studies in animals suggests that
Kp crosses the intestinal barrier and produces the liver abscess
[18,22]. Although a pathognomonic image hasn´t been defined for
the hypervirulent Kp liver abscess, they tend to present imaging
characteristics of immaturity [6,23]. The Ultrasound shows solid
masses with irregular or ill-defined margins with internal debris
images and incomplete liquefaction [6,23].
The CT findings include thin walls or badly demarcated,
septum ruptures, necrosed debris, presence of air that translates
into a delay in the abscess maturity [6,23]. There is also
described: single abscess, more solid than liquid, multilocular,
with a high percentage of association to portal and hepatic vein
thrombophlebitis [18,24,25]. Lee & cols  propose as a criteria
to imaging diagnosis of Kp liver abscess, the presence of (1) thin
walls, (2) necrosed debris, (3) metastatic infection and (4) absence
of biliary pathology
According to their study in the Asian population, the presence
of three criteria has 98% of specificity. All studied patients in this
article had the Lee and cols criteria (Figure 1-3). Generally, it is
suggested ultrasound guided percutaneous drainage as the gold
standard treatment although this procedure might be jeopardized
by a predominance of solid areas, abscess immaturity that could
lead to its failure and complement it with surgery (laparotomy or
laparoscopy) as it happened with two of the patients in this study.
Hsieh & cols  suggest that an aggressive hepatic resection
could have a better prognosis than a percutaneous drainage in
those patients that are severely ill.
There is preference to third-generation cephalosporin,
there can be also used ampicillin-sulbactam, aztreonam, and a
quinolone ; though beta lactamase producer strains are not
usual, in these cases the drug of election are the carbapenems.
The morbidity and mortality of the invasive Kp liver abscess
syndrome is substantial, with a mortality between 35 and 42%
[14-25]. Our study has several limitations as the sample is scarce,
with limitations in isolating the Hypervirulent Kp (serotypes K1
and K2). Nevertheless, the hypervirulent invasive Kp liver abscess
syndrome has a cryptogenic etiology, associated to diabetic
patients, with characteristic imaging criteria (Lee criteria) with
metastatic infections that were present in all three of the reported
patients. Despite the appropriate treatment, including the abscess drainage percutaneous or surgical in combination with
aggressive antibiotics, the result was not good. The metastatic
septic complication that led to the septic shock and multiple organ
failure contributed to its fatal outcome.
The invasive liver abscess syndrome secondary to Klebsiella
pneumoniae is a reality in Angola usually associated to cryptogenic
cause and diabetic patients. It is characterized by bacteremia
with metastatic septic complications that even with an adequate
treatment has a high morbimortality. Its diagnosis could initially
go unnoticed so a high index of clinical suspicion for an early
diagnosis and management is important.
a) It is important for the medical community not only in
Angola but also in the rest of the African continent and the world
to take into consideration this unusual and dangerous diagnosis
in our daily practice due to the extra-hepatic complications that
are generally fatal.
Microbiologists must be alert and know that a positive culture
for Kp with hyper viscosity is highly suggestive of invasive Kp,
same with radiologists when they write the medical reports of
peculiar ultrasonography and tomography images (Lee criteria)
they should immediately notify the medical doctors to consider
the possibility of this syndrome.
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Dédjan AH, Aziz Sel, Chadli A (2016) Liver Abscess in Diabetic Patients: A Case Series. Endocrinology, Diabetes & Metabolism 1) 1011: 1-4.
Maheswaranathan M, Ngo T, Rockey DC (2018) Indentification and Management of the Hypervirulent Invasive Klepsiella Pneumoniae Syndrome: A unique and distinct clinical entity. Journal of investigative medicine high impact case report 6: 1- 4.
Criales S, Lafleur A, Gervais P (2019) Liver Abscess Metastatic Syndrome Caused by Hypermucoviscous Klebsiella Pneumoniae in a Canadian Patient of Vietnamese Origin. Canadian journal of General Internal Medicine 14: 21-24.