|Year : 2022 | Volume
| Issue : 1 | Page : 21-26
Safety and efficacy of percutaneous ultrasound-guided needle aspiration of liver abscesses in a resource-scarce environment: The experience of a private diagnostic service center in kaduna over an 8-year period
Tokan Silas Baduku
Department of Radiology, Barau Dikko Teaching Hospital, Kaduna State University, Kaduna, Nigeria
|Date of Submission||26-May-2021|
|Date of Decision||01-Sep-2021|
|Date of Acceptance||22-Apr-2022|
|Date of Web Publication||07-Jul-2022|
Tokan Silas Baduku
Department of Radiology, Barau Dikko Teaching Hospital, Kaduna State University, Kaduna
Source of Support: None, Conflict of Interest: None
Background: Liver abscess is a condition found in both the developed and the developing countries (including Nigeria), which was normally treated with drugs alone. Refractory patients who were initially treated by open abdominal surgery are now successfully treated with minimally invasive approach from increased availability and access to ultrasound in low-resource settings where the burden of liver abscess is still significant. To our knowledge, not much data are available in our environment on a large series of patients with liver abscess managed solely with percutaneous needle aspiration under ultrasound guidance in combination with systemic and local abscess sac antibiotic treatment. We, therefore, report our experience in the management of liver abscess in Goshen Diagnostic Services, Kaduna, Nigeria (a private diagnostic center). Aim: The aim of this study was to describe our experience in the ultrasound-guided percutaneous management of liver abscesses over a period of 8 years in a private diagnostic center and to review the literature. Materials and Methods: This prospective study was conducted over an 8-year period at Goshen Diagnostic Services (a privately owned diagnostic outfit with only outpatient facility), Kaduna, Nigeria, from June 2012 to May 2020, involving 77 adult patients (62 male and 15 female) with liver abscess who were referred from various medical facilities within the city just for drainage purposes. Results: A total of 77 patients were eligible for the study consisting of 62 males and 15 females (male-to-female ratio of 4:1). Fifty-eight (75.3%) of them were referred from government/public hospitals, whereas 19 (24.7%) were from privately owned medical centers. Fifty-three (68.8%) patients were referred when still on admission in the various hospitals, whereas 24 (31.2%) came as outpatients. Twenty-eight percent of them required only a single aspiration, whereas 38.9% and 24.7% had to go for a second and third episode, respectively. The success rate was 100% after 6 months of follow-up. Conclusion: Liver abscess management used to be a surgical dilemma with substantial morbidity and mortality but has currently become minimally invasive. At present, morbidity and mortality have markedly diminished, with reduced cost to the patient. The direct infiltration of drugs into the abscess sac has improved the success rate.
Keywords: Antibiotics/antimicrobial instillation, liver abscess, needle aspiration, private diagnostic center, resource-limited settings, ultrasonography
|How to cite this article:|
Baduku TS. Safety and efficacy of percutaneous ultrasound-guided needle aspiration of liver abscesses in a resource-scarce environment: The experience of a private diagnostic service center in kaduna over an 8-year period. J Radiat Med Trop 2022;3:21-6
|How to cite this URL:|
Baduku TS. Safety and efficacy of percutaneous ultrasound-guided needle aspiration of liver abscesses in a resource-scarce environment: The experience of a private diagnostic service center in kaduna over an 8-year period. J Radiat Med Trop [serial online] 2022 [cited 2022 Aug 7];3:21-6. Available from: http://www.jrmt.org/text.asp?2022/3/1/21/350091
| Introduction|| |
Hepatic abscess can be defined as an encapsulated collection of suppurative material within the liver parenchyma, which may be infected by bacterial, fungal, and/or parasitic microorganisms. Amebic and pyogenic liver abscesses occur in both the developed and developing countries and continue to be an important cause of morbidity and mortality worldwide.,, The former is common in developing countries, whereas the latter is more in the developed countries., Immunocompromised hosts such as those with human immunodeficiency virus (HIV), leukemia, and diabetes are more prone to develop liver abscess with high mortality and, is more prevalent in men. Liver infection and abscess formation have the highest incidence in subtropical and tropical climates and in areas with poor sanitation., Over the past four decades, open surgical intervention has shifted to percutaneous intervention in the management of large abscesses, and image-guided percutaneous needle aspiration (PNA) has become one of the therapies of choice for the management of liver abscess., Management of liver abscess by PNA is accepted worldwide, but not much work has been done in our environment., Our study is to share our experience on the effect of abscess drainage using the PNA, followed by abscess sac infiltration with antibiotics and antimicrobial agents.
| Materials and Methods|| |
This was prospectively and intentionally designed to treat and study some outcomes among 77 adult patients (62 males and 15 females) who were referred for already diagnosed and conservatively treated ultrasound-guided PNA of liver abscess at Goshen Diagnostic Services, Kaduna (a privately owned diagnostic center), over a period of 8 years from June 2012 to May 2020 [Figure 1]. Children were excluded because they normally require general anesthesia. All the referrals were by physicians from either government or private medical establishments. The eligibility criteria were those with only right-sided lobe solitary abscesses of of up to 5.0cm diameters and above. Those patients with multiple and/or left lobe abscesses were excluded to avoid complications, since there was no admission facility in the center and intensive care resuscitation equipment were not available. Furthermore, patients with clinical features of peritonitis were excluded. All patients who were previously diagnosed by their various physicians had received antibiotics and antimicrobial drugs for a minimum of 3 weeks before their referral for abscess drainage. Some of the patients were still on therapeutic drugs as of the time they presented for the drainage. The procedure was explained to them, followed by the signing of a written consent form from the patients or their relations. Patients who refused to sign the form were excluded. The Research and Ethics Committee of the Kaduna State Ministry of Health approved the study. All the aspiration procedures were performed under sonographic guidance using an Omnia Sonoline ultrasound machine (Siemens Medical System) with a convex abdominal probe of 3.5 MHz frequency. An 18 or 20G disposable lumbar puncture (LP) needles were advanced into the abscess cavity, and the contents were aspirated in an attempt to completely evacuate the cavity, followed by irrigation of the abscess cavity with normal saline. The volume of infused saline was less than a quarter of the drained pus.
A brief history of the illness and drug therapy was taken from each patient, and the clotting and bleeding times were obtained from every patient before the procedure to prevent the risk of excess blood loss during the aspiration. Patients with bleeding diathesis were excluded from the study. Only patients with stable clotting profiles were included in the study. Both hepatitis and HIV status were also tested [Table 1]. The puncture sites were identified and marked. Cutaneous and subcutaneous anesthesia was induced by infiltration with 10 ml of 2% lidocaine hydrochloride. The needle was introduced, and continuous real-time sonographic imaging was done to localize the abscess and to guide needle insertion and progression. The tip of the needle is guided into the center of the abscess cavity [Figure 2], [Figure 3], [Figure 4], [Figure 5], after which a sample of fluid was aspirated and sent to the laboratory for bacterial culture and sensitivity before initiating the treatment.
|Figure 2: A turbid abscess cavity with rough edges within the right lobe of the liver. There was a history of prolonged antibiotic therapy before presentation|
Click here to view
|Table 1: Showing the degree to which the patients are affected by hepatitis and HIV|
Click here to view
After the culture result is known, the patient was given an appointment and aspiration of the pus was done under strict aseptic conditions. The PNA was considered successful when the cavity collapses, or was <20 ml, and/or with no relapse of abscess. Depending on the outcome of the culture and sensitivity results, drugs (sensitive antibiotics and Flagyl fluids) were instilled into the abscess cavities after every drainage episode. Broad-spectrum antibiotics/antimicrobials were also instilled into every cavity with negative culture results. In cases where the abscess contents were thick, the cavities were irrigated with normal saline before finally aspirating the contents. The patients are observed for at least 1 h before they are sent back to either the hospitals of referral or home, if there are no complaints, but with the strict instruction to contact the radiologist in case of any serious complaint (s). There was also a communication link established between the radiologist and the referring physicians. All patients were seen at 1-week interval after the first aspiration for follow-up sonography.
If further aspirations were needed, a second and/or third episode(s) were done. The sensitive drugs and 10 ml of metronidazole were then instilled into the abscess cavities following every episode of aspiration by dynamic scan, the patients were placed on oral antibiotics and metronidazol for about one week after every episode of aspiration. All patients who had negative culture results were also given broad-spectrum antibiotics to reduce the likelihood of a secondary infection. The patients were then sent back to be managed by their respective doctors until they became medically stable. The data were compiled and analyzed using commercial Statistical Product of Social Sciences (SPSS) for Windows software (version 20.; SPSS Inc., Chicago, IL, USA).
| Results|| |
After applying the inclusion and exclusion criteria, a total of 77 patients were eligible for the treatment and study consisting of 62 males (80.5%) and 15 females (19.5%), with a male-to-female ratio of 4:1 [Figure 1]. Their ages ranged from 25 to 77 years, with a mean of 53.5 years. The highest incidence of 32.5% was found in the age group of 51–60 years [Table 2]. All the patients were referred by physicians from either government or private medical establishments. Fifty-eight (75.3%) of them were referred from government/public hospitals, whereas 19 (24.7%) were from privately owned medical centers. Fifty-three (68.8%) patients were referred when still on admission in the various hospitals, whereas 24 (31.2%) came as outpatients. All patients who were previously diagnosed by their various physicians received antibiotics and antimicrobial drugs for a minimum of 3 weeks before their referral for the drainage. Few of them were still on therapeutic drugs as of the time they presented for the drainage.
All the patients for this study had their abscesses in the right lobe of the liver, which was part of the criteria for recruitment. Abscesses from the left lobe, and in cases of multiple abscesses, were excluded, since the center was not admitting patients. Those who required only a single PNA were 28 (36.4%), whereas those who required a second episode were 30 (38.9%). A third aspiration was extended to 19 persons, constituting 24.7% of the patients. There was no failure or re-accumulation after the third aspiration. The amount of the aspirated pus ranged from 350 to 4175 ml. Of these patients, abscess culture produced positive bacterial results in only 10 (13%) people. The breakdown of the types of bacterial isolates from the positive cultures was Klebsiella pneumoniae (5), Escherichia More Details coli (2), Staphylococcus aureus (2), and Streptococcus pneumoniae (1). Other tests conducted were screening for hepatitis and HIV status of all the enrolled patients. In these screening tests, 9 (11.68%) and 13 (16.88%) of patients were hepatitis B and C positive, respectively, whereas 14 (18.18%) tested positive for HIV. No abscesses recurred during the follow-up period of 6 months.
| Discussion|| |
Liver abscess was first described in the time of Hippocrates around 400 BC, as the most common type of visceral abscess. In 1938, Ochsner heralded open surgical drainage as the definitive therapy. The surgical drainage was associated with high morbidity and mortality, resulting in a drawback by both the patients and the surgeons alike. Before the introduction of high-resolution imaging techniques, 30%–50% of liver abscesses were not diagnosed until during postmortem examination. Percutaneous drainage of pyogenic liver abscess by aspiration was first performed in 1953 and was repopularized with the advancement of imaging techniques., The development of modern techniques has been accompanied by a significant reduction in the need for general anesthesia and the complications of an open abdominal surgical procedure, which include high morbidity and mortality. Ultrasound-guided percutaneous drainage is now considered the treatment of choice for those without a surgically correctable disease. We found PNA of liver abscess an easy and effective method of treatment, which has replaced surgical exploration.,
All the patients in this study had their abscesses in the right lobe of the liver, which was part of the criteria for recruitment. However, it is known that majority of liver abscesses are solitary and are located in the right lobe of the liver.,, Males were predominantly affected by this disease. In our study, there was male preponderance, with a ratio of 4:1, which agrees with many studies in almost all continents. Sreeramuli et al. had a ratio of 5.5:1, whereas Balogun et al. and Salahuddin et al. showed a ratio of 8:1,, all in favor of male preponderance. In this study, the highest incidence of 32.5% was found in the age group of 51–60 years [Table 2]. However, Balogun and Salahuddin and Balogun, had the highest incidence within the 61–70 years' age groups, but this does not correlate with a study of similar works done by Mgbor et al. and Mukhopadhyay et al., where the highest incidence was in the age group of 31–40 years., Singh et al. said that liver abscess is found more commonly in men between 20 and 40 years of age but can occur at any age.
Majority of the patients were referred from government hospitals (75.3%), whereas 68.8% were still on admission as of the time of referral. The reverse was the case in another study by Balogun et al., where only 10 (31.25%) patients were on admission at the time of drainage, whereas the majority (68.75%) were day cases. About 36% of cases required a single-needle aspiration, whereas 40% and 28% needed second and third episodes, respectively. This is similar to Kurland and Brann and Surya et al. who had extra episodes of aspiration., There was no failure or re-accumulation after the third aspiration; therefore, there was no need for surgical intervention. In this series, the amount of the aspirated pus ranged from 350 to 4175 ml. Singh et al. had a range from 100 to 3000 mL, with a mean of 850 mL, whereas Eastiak et al. aspirated a maximum of 4300 ml of abscess in one patient. Our maximum amount of abscess drained in a patient in this study was 4175 ml.
Of these patients, abscess culture produced positive bacterial results in only 10 people (13%). The breakdown of the types of bacterial isolates from the positive cultures was Klebsiella pneumoniae (5), Escherichia coli (2), Staphylococcus aureus (2), and Streptococcus pneumoniae (1). The most common species isolated by Ba et al., Kebede et al., and He et al. was K. pneumoniae,,, whereas Santos-Rosa et al. and Paul et al. isolated E. coli as the most common organisms., However, Pang et al. isolated S. pneumoniae. All the positive results were monomicrobial cultures in our series. Secondary infections have been reported as common complications of sterile abscesses such as amebic liver cavities and may affect up to 20% of them., This was not observed in this study. Antibiotics were changed and the patients were now treated based on the report of the culture and sensitivity of the aspirates that were sent to the laboratory. As for the patients whose results were bacteriologically negative, they were still placed on metronidazole and broad-spectrum antibiotics to prevent secondary infection during the aspiration.
Our series showed 14 (18.18%) patients who tested positive for HIV. Bosan et al. stated that liver abscesses are more prevalent in individuals with immunocompromised or suppressed cell-mediated immunity, with diabetic persons having a 3.6-fold increased risk for developing pyogenic liver abscess compared with the general population. Other authors have also found an emergence of liver abscess with the autoimmune deficiency syndrome pandemic who may need special medical attention. The management of all our patients was not different from other immunocompetent patients.
In our study, we adopted PNA by the use of disposable LP cannula and 20/50-ml syringes which are readily available [Figure 6]. This gave us a success rate of 100% after 6 months of follow-up. Several groups have reported reasonably good results of PNA along with systemic antibiotics only. For example, Balogun et al. and Giorgio et al. reported a 96% and 98% success rate, respectively., We attribute the high success rate of 100% in our case as probably due to the drugs being instilled into the evacuated abscess cavity. This was done to reduce infection to the barest minimum within the shortest possible time.
|Figure 6: The simple instruments used for a normal abscess aspiration. There is also a bowl of pyogenic aspirated abscess|
Click here to view
No major complications were seen. The main advantages of PNA include the following: needle aspiration under ultrasound guidance is a real-time technique that allows monitoring of the course of the needles. It is also less invasive, less expensive, and easily available and avoids the problems of ionizing radiation and prolonged nursing care., However, the safety of PNA also relies on the skills of an experienced radiologist and strict adherence to the protocol of the procedure. Despite the reported success of percutaneous drainage techniques, there remains a role for open surgical intervention in the management of abscesses.,
One of the limitations of PNA is that many centers are not involved in the percutaneous drainage of liver abscess possibly due to unavailability of suitable percutaneous drainage sets, unavailability of ultrasound machine at treatment site, and absence of experienced hands. A major drawback was our inability to carry out serology investigations on the patients, resulting in patients with amebic abscess and possibly secondary pyogenic infection being missed. Many medical centers in the tropics do not have facilities for serological tests.,, Our institution is a diagnostic center with no facility for admission, and many of these patients had been partially treated with both antibiotics and antimicrobial drugs. This probably accounts for the high percentage of negativity in abscess culture results.
This study excluded patients with abscess in the left lobe of the liver because it is said to be more liable to rupture than that on the right, and we did not adequate facilities for the management of emergencies. Another important reason for failure of needle aspiration is that it has no inability to completely evacuate the thick viscous pus that may be present in some of the abscess sac,, hence the instillation of normal saline by us to dilute any thick abscess before its aspiration. Re-accumulation of abscess is another reason described as a limitation of needle aspiration.,
One other important reason for failure of needle aspiration is the inability to completely evacuate the thick viscous pus that may be present in some of the abscesses even after dilution with normal saline. The treatment of liver abscess by aspiration is based mainly on the personal experience of clinicians since there is no uniformly set standards. It is universally known that needle aspiration combined with antibiotics/antiamebics is a safe and more effective procedure than drug treatment alone in the management of liver abscess., 'Instillation of drugs into abscess cavities after abscess aspirations also increases the degree of quick recovery. However, an improvement on the outcome of percutaneous drainage of liver abscesses requires further studies.
| Conclusion|| |
This study represents our preliminary work on liver abscess drainage. We found that a combination of needle aspiration, systemic antibiotics/antiamebics, and the instilling of these drugs into abscess cavity represents a successful therapeutic approach in the management of liver abscess whether it is pyogenic or amebic. It offers a safe and economical therapeutic approach, with high clinical recovery, and prevents complications.
Financial support and sponsorship
Conflicts of interest
There are no conflicts of interest.
| References|| |
Lardière-Deguelte S, Ragot E, Armoun K, Piardi T, Dokmak S, Bruno O, et al.
Hepatic abscess: Diagnosis and management. J Visc Surg 2015;152:231-43.
Mavilia MG, Molina M, Wu GY. The evolving nature of hepatic abscess: A review. J Clin Transl Hepatol 2016;4:158-68.
Egba RN, Asuquo M, Ugare GU, Udoh I. Closed drainage of liver abscesses: The 'UNICAL' drain as an efficient and cost saving device in a tropical setting. Niger J Clin Pract 2008;11:396-9.
Eastiak MF, Alam SM, Nur-E-Elahi M, Faruk I, Mousumi MS, lslam MR, et al
. Pigtail catheter in the management of liver abscess. J Surg Sci 2014;18:3-8.
Salahuddin G, Parvin S, Mollick MK, Hossain SM. Safety and efficacy of ultrasound guided percutaneous needle aspiration of liver abscess. Bang Med J Khulna 2018;51:3-6.
Ba ID, Ba A, Faye PM, Diouf FN, Sagna A, Thiongane A, et al.
Particularities of liver abscesses in children in Senegal: Description of a series of 26 cases. Arch Pediatr 2016;23:491-6.
Diarra A, Keita K, Traore A, Koné A, Konate M, Tounkara I, et al
. Liver abscesses: What diagnostics and therapeutics in the Kati Reference Health Center (Mali)? Surg Sci 2018;9:344-50.
Desoubeaux G, Chaussade H, Thellier M, Poussing S, Bastides F, Bailly E, et al.
Unusual multiple large abscesses of the liver: Interest of the radiological features and the real-time PCR to distinguish between bacterial and amebic etiologies. Pathog Glob Health 2014;108:53-7.
Khim G, Em S, Mo S, Townell N. Liver abscess: Diagnostic and management issues found in the low resource setting. Br Med Bull 2019;132:45-52.
Bosan IB, Baduku TS. Amoebic liver abscess: A diagnostic dilemma in the elderly. Ann Afr Med 2003;2:33-5.
Balogun BO, Olofinlade OO, Igetei R, Onyekwere CA. Ultrasound-guided percutaneous drainage of liver abscess: 6 years-experience in Lagos State university teaching hospital, Lagos. Niger J Surg Res 2013;15:13-6. [Full text]
Haider SJ, Tarulli M, McNulty NJ, Hoffer EK. Liver abscesses: Factors that influence outcome of percutaneous drainage. AJR Am J Roentgenol 2017;209:205-13.
Singh S, Chaudhary P, Saxena N, Khandelwal S, Poddar DD, Biswal UC. Treatment of liver abscess: Prospective randomized comparison of catheter drainage and needle aspiration. Ann Gastroenterol 2013;26:332-9.
Law ST, Li KK. Older age as a poor prognostic sign in patients with pyogenic liver abscess. Int J Infect Dis 2013;17:e177-84.
Heneghan HM, Healy NA, Martin ST, Ryan RS, Nolan N, Traynor O, et al
. Modern management of pyogenic hepatic abscess: A case series and review of the literature. BMC Res Notes 2011;4:80 doi.org/10.1186/1756-0500-4-80.
Malik AA, Bari SU, Rouf KA, Wani KA. Pyogenic liver abscess: Changing patterns in approach. World J Gastrointest Surg 2010;2:395-401.
McFadzean AJ, Chang KP, Wong CC. Solitary pyogenic abscess of the liver treated by closed aspiration and antibiotics; a report of 14 consecutive cases with recovery. Br J Surg 1953;41:141-52.
Kaminstein D, Heller T, Tamarozzi F. Sound around the world: Ultrasound for tropical diseases. Infect Dis Clin North Am 2019;33:169-95.
Brunetti E, Heller T, Richter J, Kaminstein D, Youkee D, Giordani MT, et al
. Application of ultrasonography in the diagnosis of infectious diseases in resource-limited settings. Curr Infect Dis Rep 2016;18:6. doi.org/10.1007/s11908-015-0512-7.
Errey AK, Singh SK, Sachan N, Singh V. Assessment of outcome and complications of ultrasonography guided pigtail catheter drainage in management of liver abscess. Int Surg J 2020;7:1825-9.
Mohan S, Talwar N, Chaudhary A, Andley M, Ravi B, Kumar A. Liver abscess: A clinicopathological analysis of 82 cases. Int Surg 2006;91:228-33.
Sreeramulu PN, Swamy SD, Vikranth SN, Suma S. Liver abscess: Presentation and an assessment of the outcome with various treatment modalities. Int Surg J 2019;6:2556-60.
Mgbor SO, Eke CI, Onuh AC. Amoebic liver abscess: Sonographic patterns and complications in Enugu, Nigeria. West Afr J Radiol 2003;10:8-14.
Mukhopadhyay M, Saha AK, Sarkar A, Mukherjee S. Amoebic liver abscess: Presentation and complications. Indian J Surg 2010;72:37-41.
Kurland JE, Brann OS. Pyogenic and amebic liver abscesses. Curr Gastroenterol Rep 2004;6:273-9.
Surya M, Bhoil R, Sharma YP. Study of ultrasound-guided needle aspiration and catheter drainage in the management of liver abscesses. J Ultrasound 2020;23:553-62.
Eastiak MF, Saifullah M, Islam MS, Hossain MJ, Mannan M, Mousumi MS, et al
. Pigtail catheter in the management of liver abscess. Mymensingh Med J 2015;24:770-5.
Kebede A, Kassa E, Ashenafi S, Woldemichael T, Polderman AM. Amoebic liver abscess: A 20-year retrospective analysis at Tikur Anbessa Hospital, Ethiopia. Ethiop J Health Dev 2004;18:199-202.
He S, Yu J, Wang H, Chen X, He Z, Chen Y. Percutaneous fine-needle aspiration for pyogenic liver abscess (3-6cm): A two-center retrospective study. BMC Infect Dis 2020;20:516.
Santos-Rosa OM, Lunardelli HS, Ribeiro-Junior MA. Pyogenic liver abscess: Diagnostic and therapeutic management. Arq Bras Cir Dig 2016;29:194-7.
Paul SN, Jain VK. Clinico-pathological study of liver abscesses with special reference to different treatment options. Int Surg J 2019;6:1-5.
Pang TC, Fung T, Samra J, Hugh TJ, Smith RC. Pyogenic liver abscess: An audit of 10 years' experience. World J Gastroenterol 2011;17:1622-30.
Al Amer NA, Abd El Maksoud WM. Abscess of the caudate lobe of the liver, a rare disease with a challenging management: A case report. J Biomed Res 2013;27:430-4.
Giorgio A, de Stefano G, Di Sarno A, Liorre G, Ferraioli G. Percutaneous needle aspiration of multiple pyogenic abscesses of the liver: 13-year single-center experience. AJR Am J Roentgenol 2006;187:1585-90.
Yu SC, Ho SS, Lau WY, Yeung DT, Yuen EH, Lee PS, et al.
Treatment of pyogenic liver abscess: Prospective randomized comparison of catheter drainage and needle aspiration. Hepatology 2004;39:932-8.
Baban FA. Clinical characteristic of amoebic liver abscesses in the North of Iraq. Saudi Med J 2000;21:545-9.
Nasr B, Derbel F, Barka M, Farhat W, Sghaier A, Mazhoud J, et al
. Presentation and management of pyogenic liver abscess in surgery department: About 34 cases. J Gastroenterol Hepatol Res 2014;3:1349-56.
Zafar A, Ahmed S. Amoebic liver abscess: A comparative study of needle aspiration versus conservative treatment. J Ayub Med Coll Abbottabad 2002;14:10-2.
[Figure 1], [Figure 2], [Figure 3], [Figure 4], [Figure 5], [Figure 6]
[Table 1], [Table 2]