Indications for aspiration of amoebic liver abscess. Treatment of amoebic liver abscess with metronidazole alone or in combination with ultrasound-guided needle aspiration: a comparative, prospective and randomized study. Uncomplicated amebic liver abscess: prospective evaluation of percutaneous therapeutic aspiration. Amoebic liver abscess: ultrasonographic characteristics and results of different therapeutic approaches. Needle aspiration in large amoebic liver abscess. Prophylactic metronidazole in appendectomy: a double-blind controlled trial. Prophylactic metronidazole in appendicectomy: a controlled trial. Comparison of systemic prophylaxis with metronidazole/placebo and metronidazole/fosfomycin in colorectal surgery. A clinical study demonstrating the need for additional anti-aerobic prophylactic cover. Single dose cefuroxime/metronidazole versus metronidazole alone in elective colorectal surgery.
A two-part study was undertaken to determine whether aspiration of amoebic liver abscess (ALA) prevents complications. Eighty patients studied prospectively were randomised into aspiration or non-aspiration groups and were treated with metronidazole. Common factors in patients with complicated diseases were determined to formulate and test indications for aspiration. Records of all patients with ALA admitted to King Edward VIII Hospital, Durban, between October 1983 and December 1984 were analysed to test the validity of the criteria derived from the first part of the study. The findings suggest that aspiration influences the course and outcome of ALA and that the criteria are valid although not necessarily complete. Thirty-nine patients with amoebic liver abscess (ALA), admitted to the Central Hospital of Hué (Vietnam), were evaluated in a comparative, prospective and randomized study for the treatment of ALA. Adult patients with an abscess located in the right liver lobe and an abscess diameter of 6 to 10 cm were included. Bacterial abscesses were excluded by microbiological examination of abscess fluid in all patients. Nineteen patients were treated with metronidazole for 10 days alone and 20 patients were punctured under ultrasound guidance with aspiration of abscess fluid in addition to drug administration. The clinical symptoms fever, pain in right upper abdomen and liver tenderness, and the laboratory parameters erythrocyte sedimentation rate, white blood cells, haemoglobin and C-reactive protein and the abscess size were determined on the day of admission and followed during an observation period of 38 days. Improvement of liver tenderness was significantly faster in the aspiration group during the first 3 days (P < 0.001), whereas all the other parameters showed no differences between the two groups. This minor benefit is obviously not sufficient to justify routine needle aspiration and advocates drug treatment alone for uncomplicated amoebic liver abscesses with a diameter up to 10 cm located in the right liver lobe. The performance of therapeutic aspiration in the treatment of amebic liver abscess, advocated and practiced in many centers, is controversial. Previously, this practice has been evaluated in retrospective analyses. To test the potential benefit of therapeutic aspiration, the authors undertook a prospective randomized trial in 57 patients admitted for suspected amebic liver abscess during a 15-month period. Sixteen patients were excluded from the trial. The remaining 41 patients were randomly included in one of two study groups to receive amebicidal therapy alone or amebicidal therapy coupled with image-guided percutaneous therapeutic aspiration. All patients in the trial recovered. No statistically significant benefit was demonstrated in the aspiration group for the two objective parameters evaluated: length of hospitalization and duration of time to becoming afebrile. Subjective improvement in symptoms after aspiration was greater in the aspiration group at a marginally statistically significant level. These data do not support the adjunctive performance of percutaneous therapeutic aspiration in the treatment of uncomplicated amebic liver abscess. Amebicidals alone were equally efficacious in treating the group studied. This prospective study was carried out on 33 patients with clinically, serologically and ultrasonographically confirmed amoebic liver abscess. All patients were randomly treated with metronidazole and chlorochin or a combination of medicamentous therapy and percutaneous drainage. Ultrasonographic characteristics of amoebic liver abscesses were rotound or oval shape, usually hypoechogenic content with specific dorsal sonic enhancement, and in the majority of cases, location near liver capsule. Shorter duration of amoebic liver abscess resolution time in the group of patients treated with the combined therapy was observed particularly in the first four weeks of the treatment. The authors concluded that percutaneous drainage in combination with medicamentous therapy represents a successful therapeutic approach in the treatment of amoebic liver abscesses. The role of percutaneous needle aspiration for therapy of uncomplicated, large amoebic liver abscess (ALA) is not defined. Twenty nine patients of ALA with a cavity larger than 5 cm were randomised to two groups: (i) metronidazole 800 mg tid for 10 days combined with needle aspiration (group A, n = 15) and (ii) metronidazole therapy alone (group B, n = 14). Clinical parameters, viz, fever, pain and abdominal tenderness were recorded daily and graded 0 to 3 (in order of increasing severity). A statistically significant benefit was demonstrated in group A for clinical parameters evaluated. Group A patients took less time to become afebrile from the grade 2 level as compared to group B (3.8 +/- 1.7 days and 5.6 +/- 2.2 days respectively; p < 0.05). Reduction in pain intensity and abdominal tenderness from grade 2 to 1 also occurred earlier in group A (0.7 +/- 0.7 days vs 2.9 +/- 0.9 days for pain, P < 0.001 and 1.7 +/- 0.8 days vs 2.9 +/- 1.2 days for abdominal tenderness, p < 0.001). The mean duration of hospitalization was significantly shorter in group A as compared to group B (5.8 +/- 0.8 days vs 7.4 +/- 1.5 days, p < 0.001). Improvement in haematological and biochemical variables was similar in both groups. We conclude that percutaneous therapeutic needle aspiration of uncomplicated, large ALA hastens clinical recovery. Ninety-eight patients with suspected nonperforated acute appendicitis have to date been entered into a continuing, prospective, blinded randomized trial to determine the role of prophylactic metronidazole in postoperative wound infection. Twenty-six patients were excluded for the following reasons: diagnosis other than acute appendicitis (16), perforation of the appendix (8), administration of other antibiotics (1), and refusal to enter study (1). Seventy-two patients, 47 men and 25 women, with a mean age of 27.5 years (range 15 to 60 years), underwent appendectomy and were studied. Thirty patients received 1 gm intravenous metronidazole preoperatively and five intravenous doses of 500 mg metronidazole postoperatively. Forty-two patients received placebo only. Cultures of the appendiceal stump grew aerobic cultures in 45 (62%) and anaerobic organisms in 29 (40%): Escherichia coli and Bacteroides fragilis, respectively. Six of the 72 patients (8.2%) developed postoperative wound infections: four of 42 (9.5%) who received placebo and two of 30 (6.6%) who received metronidazole (P = 0.54 by Fisher exact test). No toxicity from metronidazole was observed. The postoperative wound infection rate is insufficient to demonstrate the efficacy of metronidazole for prophylaxis in nonperforated acute appendicitis, although there appears to be a tendency of to assume its efficacy in this regard. Prophylactic metronidazole was compared with no treatment in a randomly allocated study of patients undergoing appendicectomy. A 1-g suppository of metronidazole was given with the premedication and 200 mg t.d.s. orally for 7 days thereafter. There were 4 hospital wound infections in the 87 patients receiving metronidazole and 11 out of 83 in the no-treatment group (P < 0.05). However, 60 per cent of wound infections occurred at home and the overall infection rates were not significantly different. The duration of postoperative hospital stay was longer in the control group (5.8 days +/- 3.0 s.d.) than in the treated group (4.8 +/- 2.3; P < 0.01). Only one anaerobic infection occurred in a patient receiving metronidazole but late infection was not prevented. Blood levels of metronidazole taken at the end of operation showed a wide variation but there was no correlation with subsequent infection. Culture of the appendix showed aerobic organisms in 88 per cent of cases and anaerobes in 72 per cent. It is suggested that an antibiotic which is effective against both aerobic and anaerobic organisms might have an advantage over metronidazole in appendicitis. The aim of this randomized double-blind study comparing the efficacy of two prophylactic regimens, metronidazole/placebo (n = 23) and metronidazole/fosfomycin (n = 26) was two-fold. First, to evaluate the need for anti-aerobic cover in addition to short-term systemic administration of metronidazole against anaerobes in colorectal surgery. Secondly, to explore the prophylactic effect of fosfomycin on aerobes of intestinal origin. An unacceptably high rate of surgical sepsis (16.3%) forced premature conclusion of the study after 49 patients had entered it. All surgical and remote infections occurred in the metronidazole/placebo group and were caused solely by aerobes. Anaerobic sepsis was not seen at all and the surgical infection rate was 34.8%. No septic complications occurred in the 26 patients (0%) receiving metronidazole/fosfomycin (p less than 0.01). Thus the study demonstrated both the need to administer an effective anti-aerobic agent in addition to metronidazole in colorectal surgery and the efficacy of fosfomycin in preventing aerobic sepsis of intestinal origin. Adverse reactions to the two drugs were not observed and resistance did not occur. Sixty assessable patients undergoing elective colonic and rectal surgery were randomly allocated to receive prophylaxis with a combination of 1.5 g cefuroxime plus 500 mg metronidazole or 500 mg metronidazole alone as single doses by the intravenous route, given at the beginning of anesthesia. The two groups were matched for age, sex, malignancy, and type of operation. Primary wound infections were observed in one patient (3.7%) in the combination group and six (18.2%) in the group given metronidazole alone. This trend was not statistically significant. Bacteriologic examination of the anastomoses, abdominal walls, and wounds showed significantly more sterile cultures in the combination group, although more aerobic cefuroxime-resistant isolates were seen in this group. There is no evidence that the emergence of resistant strains had any influence on the outcome of patients in the study. It was concluded that an appropriate antibiotic prophylactic regimen for colorectal surgery should be directed against aerobic and anaerobic organisms. Cefuroxime plus metronidazole is an effective regimen for the prevention of postoperative infection.
Therapeutic aspiration in addition to metronidazole to hasten clinical or radiologic resolution of uncomplicated amoebic liver abscesses cannot be supported or refuted by the present evidence. The trials lack methodological rigour and adequate sample size to conclude on the presence of effectiveness of adjunctive image-guided aspiration plus metronidazole versus metronidazole alone. Further randomised trials are necessary.