Invasive amoebiasis

Introduction
Amoebiasis is a rare parasitic disease in the temperate zone which may be underestimated or even not recognized initially.

Case report
A 55 year old male patient had been diagnosed with acute appendicitis in a peripheral hospital. His history revealed malaria and several episodes of diarrhea, during a long professional stay in Nigeria. An emergency appendectomy was performed. The patient's postoperative followings were complicated by diarrhea, fever, chills, signs of septic shock and renal failure. The patient was admitted urgently, seven days after the appendectomy, to the 3rd Surgical Unit of "St Spiridon" Hospital of Iasi. The patient was diagnosed in the first 48 hours from his admission with invasive amoebiasis by identification of parasitic cysts and trophozoites of Entamoeba Histolytica (E.H.) in the stool and urine samples. No immunological tests for E.H. were available. Amoebicidal therapies associated to a broad spectrum of antibiotic and antimycotic therapy were initiated: Chloroquine 300mg/24 h, Imipenem 0,5 g / 12 h, Diflucane 200mg / 24 h, also Metronidazole 1g / 12 h.
The abdominal ultrasound followed by whole body examination by enhanced computed tomography (CT) revealed an enormous spheroid liver abscess (15/10/10 cm), occupying most of the volume of the right lobe, bordered with some calcifications (Fig. 1) The rest of the liver parenchyma was of normal aspect. Another fluid collection 6/4/3 cm was identified in the right iliac fosa (Fig. 2). The kidneys were noted also with an increased volume. The thoracic and brain CT scan were normal.
The operative scare of the appendectomy became progressively reddish and painful and a stercoral fistula has occurred spontaneously soon after the admission. The amoebic trophozoites and enteral flora were identified in the secretion.
The first step of the surgical treatment was continuous sucction drainage of the right iliac fosa by placing a polyorificial tube; 72 hours after, the abdomen was less distended and less painful.
After five days of treatment in the intensive care unit, the surgical approach was decided. The liver abscess had been surgically evacuated (900 ml average of "milk chocolate" like fluid and necrotic detritus), then rinsed with 0,5 % metronidazol solution and drained with two suction tubes.
Favorable followings were noted in the next days under amoebicidal drugs. Continuous drainage was maintained in the right iliac fosa. Six weeks after, the liver remnant cavity measured 6/6/5 cm; three consecutive microscopic examinations of secretion samples from the tubes draining the liver remnant cavity were negatives for E.H. The patient counted seven weeks of hospital stay. The patient has lived the hospital with no drainage tube of the liver abscess; the enteral fistula was covered by a coclostomy pouch. He returned home under the supervision of a general practitioner.
Four weeks later the patient was readmitted for pain in the right upper abdominal region, fever, chills, sweats and a mild alteration of the general status. The remnant cavity of the liver abscess had doubled in size - 13/12/10 cm - since the last evaluation (Fig. 3). Also a chronic stercoral fistula was still present in the right iliac fosa.
The indication for a second surgical approach was decided: about 800 ml of "anchovy paste" like fluid was evacuated through a small breach in the liver parenchyma of the segment VI. Thereafter, we have performed the resection of the peripheral wall for a large opening of the remnant cavity (a hemispheric ablation of the cavity wall - Fig. 4). The microscopy revealed again both forms (trophozoites and cysts) of Entamoeba Hystolitica and Cocci Gram (+) in some detritus from the remnant cavity. The remnant cavity was plugged with great omentum and drained with two polyorificial tubes. The operation is continued with the ileo-caecal resection and excision of the scare of the abdominal wall, followed by side to side anastomosis of the ileum to the ascending colon. The pathology examination confirmed the chronic inflamation but no amoebic bodies. Postoperatively, the antibiotic therapy (Vancomycin 1 g/ 24 h) based on culture of the liver abscess fluid (Staphylococcus aureus) has been administered for 7 days. The amoebicidal agent (Metronidazole 1g / 12 h) was administered again up to three weeks. Finally, the patient was considered healed twelve months after the diagnosis of the systemic amoebiasis.

Discussions
The unusual parasitic pathology for the temperate zone must be taken into consideration for the patients who come from an endemic region. The amoebic infection of the digestive tract can spread out systemically and could lead to multiple amoebic locations - invasive amoebiasis. An amoebic liver abscess is the most common extra-intestinal manifestation of amoebic infection (1, 2). The presence of both amoebic forms in urine samples has proved, in our patient, the invasive extradigestive amoebiasis.
The amoebicidal drugs as first therapeutic option, didn't have the favorable results as mentioned in most reports (3, 4, 5, and 6).
The CT or ultrasound guided drainage of the abscess, as mentioned in many reports (7, 8), were not feasible, because of the calcifications of the abscess wall. Also a high risk of peritoneal dissemination was considered.
The involution of the remnant cavity after surgical or percutaneous drainage required long-term maintenance of the drainage tubes, with the risk of nosocomial infection (Staphylococcus aureus). However, the sterilization of the remnant cavity was not sure even after long-term drainage and amoebicidal treatment (9). The chronic liver abscess seems to be the most probable evolution of the large remnant cavity.
We have considered that a limited liver resection (corresponding to segmentectomy or bisegmentectomy) could be performed safely in the same operative session with the abscess evacuation. The amoebicidal treatment and antibiotherapy accorded to the culture were associated. Amoebic enteritis complicated with perforation, leads to a chronic enteral fistula. The surgical treatment is recommended if the fistula did not close spontaneously. The excision of the fistula with or without limited resection of the segment of the bowel involved, may shorten the local evolution.

Conclusions
A multidisciplinary approach of a patient diagnosed with invasive amoebiasis allowed successful treatment and complete healing of this. For a large liver amoebic abscess, the treatment requires surgical evacuation and large opening of the abscess cavity by liver resection. We consider this the best way to treat the remnant cavity. Chronic enteric fistula following perforation by E.H. enteritis may also require surgical resection.

Acknoledgement
Many thanks to Dr. Constantin Scurtu - Tropical Infectious Disease Department, Dr. Cristina Petrovici - Microbiology Laboratory of Infectious Disease University Hospital, and Dr Adriana Pricop, Dr. Mihai Grigoras - Department of Radiology, Dr. Elena Florea -Department of Pathology, St Spiridon University Hospital, for their help in the investigation of the patient.

References
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