Role of ultrasound guided biopsy and ultrasound guided fine needle aspiration biopsy in the diagnosis of hepatic affections in dogs Singh C.2, Mahajan S.K.2,*, Mohindroo J.2, Sood N.K.1,2, Saini N.S.2, Singh S.S.2 2Department of Veterinary Surgery and Radiology, College of Veterinary science, Guru Angad Dev Veterinary and Animal Sciences University, Ludhiana (India) 1Dept. of Veterinary Pathology,College of Veterinary science, Guru Angad Dev Veterinary and Animal Sciences University, Ludhiana (India) *Corresponding author
Abstract The clinical study was conducted on 24 clinical cases of dogs for various liver disorders by ultrasound guided biopsy (USGB) in 8 cases and ultrasound guided fine needle aspiration biopsy (USG-FNAB) in 16 cases. In case of hepatosis, ultrasonographically the liver was hypoechoic with multiple hyperechoic areas. The cytological findings ranged from mild to severe fatty change, degeneration and necrosis of the hepatocytes and histopathological findings ranged from moderate to marked degenerative changes in hepatocytes, sinusoidal congestion and atrophy of hepatocytes. In case of hepatitis, ultrasonographically the hepatic parenchyma was hyperechoic in general. The cytological findings ranged from marked degeneration and necrosis of hepatocytes, mild to moderate fatty changes along with neutrophilic infiltration and histopathological findings ranged from multifocal chronic hepatitis, chronic cholangiohepatitis along with fibrosis and mild mononuclear cell infiltration. Insignificant (non-diagnostic) cytological/histopathological findings were seen in three cases. Ultrasonography helped characterization of liver parenchyma for change in size and echotexture. Hepatitis and hepatosis were the conditions which were diagnosed with USGB and USG-FNAB in dogs. Top Keywords Fine needle aspiration biopsy, Hepatitis, Hepatosis, Liver, Ultrasound guided biopsy. Top |
INTRODUCTION The evaluation and management of hepatic disease is very challenging for a veterinary clinician. Hematobiochemical tests are usually inadequate for the establishment of an etiologic diagnosis, specific therapy and prognosis. Lack of contrast in the abdomen limits the precision of abdominal radiography. Ultrasonography has the ability to diffrentiate various soft tissue densities, which makes it possible to locate organs and lesios not visible radiographically. The ultrasound guided biopsy (USGB) can help to make a definitive diagnosis of pathological condition, and also to assess an organ function. In veterinary medicine, fineneedle aspiration and tissue core biopsy of liver are the most common procedures performed under US guidance. The technique is inexpensive, rapid, and minimally invasive and requires no general anesthesia. An advantage is that the needle can be visualized and guided into the target organ, making more accurate than blind punctures. Aspiration biopsy is obtained with needle ranging in size from 20–22 gauges. The term fine needle aspiration biopsy (FNAB) is reserved for the use of smaller than 20 gauge3. The second technique, tissue core biopsy, using larger (14–18 G) automated needles has advantage of yielding sufficient tissue plugs for histopathological examination. Fine-needle aspiration is associated with less risk than biopsy because of the smaller size of the needle and lesser need for heavy sedation or anesthesia. Therefore, the aim of the present study was to assess the efficacy and diagnostic value of ultrasound guided biopsy and ultrasound guided fine needle aspiration biopsy in cases of hepatic affections in dogs. |
Top MATERIALS AND METHODS The present study was conducted on 24 clinical cases of dogs of either sex, aged 4 months to 12 years and body weight ranging from 4 to 35 kg presented at the small animal teaching hospital, GADVASU, Ludhiana with varying symptoms. All the animals were subjected to systematic evaluation for diagnosis of diseases. Hematological and biochemical parameters including serum AKP (μ/L), SGPT (μ/L), SGOT (μ/L), BUN (mg/dL), creatinine (mg/dL), TLC (×103 per ml), DLC (%), Hb (g/dl), total protein and albumin (g/dL) were determined depending upon the case. Ultrasound-guided core biopsy (USGB) samples were collected in eight cases using a Bard's disposable biopsy gun and ultrasound guided fine needle aspiration biopsy (USG-FNAB) samples were collected in 16 cases of hepatic affections using 20–22 gauge needle attached to a 10 ml syringe employing free hand technique. Survey abdominal radiography and ultrasonography were performed in all the cases. The findings of above parameters were correlated to arrive at a definitive diagnosis. Platelet adequacy was determined in some critical cases, where USGB was carried out. Ultrasonography was carried out using a concept/MCV Veterinary Ultrasound scanner (a gray scale, real time, B-mode scanner), with 3.5 MHz micro convex and 7.5 MHz linear array transducer. USGB was carried out in dorsal recumbency in non-anesthetized animals. In few cases local infiltration anesthesia was injected at the site where patients were non-cooperative during the procedure. The instrument used for all biopsies was Bard Max core disposable biopsy instrument, which was resterilized and reused. The size of the needle was 18g ’ 16 cm in length. The length of sample notch was 1.8 cm and depth of the penetration was 22 mm. The needle was pierced at an angle from ultrasound transducer through the skin, as the organ was being visualized on the monitor. Biopsy of liver was made in maximum one or two attempts and a post biopsy scan was done to check the haemorrhage. The tissue samples thus obtained were immediately stored in 10% buffered formalin for histopathological examination. USG-FNAB was done using a 20-22g needle attached to a 5–10 ml syringe. The needle was advanced slightly oblique to the long axis of transducer through the skin. When the needle was seen in middle of the lesion, moderate and rapidly repeated suction (appx. 3- 6 times) was applied to the syringe plunger while the needle was moved within the lesion. Smears were made from tissue samples and stained (Wright/Giemsa stain) for cytological evaluation. |
Top RESULTS AND DISCUSSION Based on clinical, biochemical, radiological, ultrasonographic and cytological/histopathological findings, lesions/diseases were broadly divided into three categories, viz. hepatosis (those having predominantly degenerative changes), hepatitis (those having predominantly degenerative and inflammatory changes) and non-diagnostic samples (in which sample was not diagnostic). |
Hepatosis Hepatosis was diagnosed in four animals (three males and one female) suffering from liver disorders, with an average age of 6.38±1.90 years (2–11 years) and a mean body weight of 20.42 ±2.43 kg (14–26 kg) on the basis of cytological examination from samples collected by USG-FNAB. Hepatosis was recorded in another four cases (three male and one female) with an average age of 8.12±2.37 years (1.5–12) and mean body weight of 27.50±3.25 kg (19–36) on the basis of histopathological examination from samples collected by USGB. However, Mahajan10 reported an average age of 9 months and mean body weight of 13 kg in hepatosis. The clinical signs in hepatosis included vomition, abdominal distension, reduced feed intake, and black colored loose faeces10,19. Ascites was seen in three cases. Rectal temperature was normal in two cases and moderately elevated in rest of the cases. Heart and respiration rates were moderately elevated in all except one case. Conjunctiva was yellowish-white in all except two where it was congested. The blood SGPT, SGOT values were elevated in all cases (Table 1). AKP values were moderately elevated in all cases except in two cases in which it was markedly elevated. The BUN, creatinine, and total protein levels were within the normal range. Total platelet counts were adequate in all except one case where it was low. The animals were usually anaemic in all cases which may be the result of increased degradation of RBC in most hepatobiliary disease19 and had neutrophilic leucocytosis in all except one case. The neutrophilic leucocytosis is characteristic of acute inflammatory conditions4,19. The increase in SGPT and AKP values can be attributed to hepatocellular injury caused by various stimuli or factors. The SGPT is a liver specific cytosolic enzyme in dogs9. Increase in SGPT and AKP was observed most often with hepatocellular necrosis and inflammation and magnitude of elevation was roughly proportionate to the number of injured hepatocytes18. The increased level of SGOT may also be associated with leakage following altered membrane permeability5. The loose faeces in the liver disease could be due to cholestasis caused by endotoxins and increased resistance to portal blood flow, leading to congestion of intestinal vasculature, decreasing intestinal water resorption15. The lateral radiographs of the abdomen showed ground glass appearance in three cases indicative of ascitic fluid. Hepatomegaly was recorded in three cases characterized by extension of margins of liver well beyond costal arch on lateral radiograph10,12,14. In two cases radiograph revealed no apparent abnormality. Accurate radiographic evaluation of generalized and mild changes in hepatic size have been found to be difficult1,7. Johnson8 also observed that when ascites is present, the liver size might be difficult to evaluate on the survey films. Ultrasonographically, the liver was hypoechoic in general with hyperechoic areas in all cases in the present study10,19 (Fig.1). The hypoechogenicity might be caused by the degenerative changes in the liver. Selcer16 opined that most common causes of diffuse decreased liver echogenicity include chronic passive congestion resulting from dilation of hepatic sinusoids and hepatitis, owing to swelling of hepatocytes. The hypoechogenicity of the liver may be attributed to increased blood volume or due to uniform cellular infiltration, leading to swelling of hepatocytes which, being less attenuating to the ultrasonographic beam than normal parenchyma, appears hypoechoic2,11. The cytological changes (USG-FNAB) in all the four cases ranged from mild to severe fatty change (Fig 2), degeneration and necrosis of the hepatocytes. Similar cytological findings were also reported by Mahajan10. However, Weiss and Moritz20 reported that cytologically hepatocytes appear indistinct with vacuolar degeneration of cytoplasm in degenerative conditions like hepatosis. The histopathological examination (USGB) revealed marked degenerative changes in hepatocytes and sinusoidal congestion and atrophy of hepatocytes in two cases (Fig 3), moderate degenerative changes in hepatocytes and marked congestion of liver in rest of the two cases. Similar histopathological findings were also recorded by Mahajan10. In the present study, ultrasonographic findings corroborated with the hematobiochemical parameters and it was possible to identify alterations in internal hepatic architecture and parenchyma. The cytological/histopathological findings were also correlated with the clinical, hematobiochemical and ultrasonographic findings. Radiography was not much helpful in the diagnosis of the diseased conditions of liver in most cases. However, hepatomegaly could be diagnosed on the lateral radiographs except in cases of ascites. Hepatitis Hepatitis was diagnosed in 10 animals (nine males and one female) with an average age of 5.32±.966 years (2-11years) and mean body weight of 23.90±2.324 kg (12- 35 kg) on the basis of cytological examination of samples collected by USG-FNAB as reported previously19. Hepatitis was also seen on the basis of histopathological examination of samples collected by USGB from three male animals. Clinical signs were similar to those seen in the cases of hepatosis. One case had the history of haematuria for last 3–4 days. Rectal temperature was normal in all except moderately elevated in two cases and high in another two cases. Heart and respiration rates were generally moderately elevated. The blood SGPT, SGOT and AKP values were generally moderately elevated (Table 2) which could be attributed to hepatic cell damage or biliary obstruction associated with hepatic inflammation4. However, an increase in AKP alone is nonspecific and is said to reflect the proliferation of bile ductule epithelium that is seen with biliary obstruction and hepatic regeneration13, and large amounts of AKP are normally found in bile duct epithelium17. Other serum parameters were generally within the normal range. The animals were usually anaemic which could be the result of increased degradation of RBCs in most hepatobiliary diseases and had neutrophilic leucocytosis, characteristic of acute inflammatory conditions4,19. Johnson8 also found that dogs with chronic inflammatory liver diseases had higher peripheral blood mononuclear cell proliferation in response to liver membrane protein. There was fall in hemoglobin levels of all the animals in this group. The low levels of haemoglobin and hence anaemia in hepatobiliary diseases could be attributed to increased degradation of red blood cells. The possible cause of degradation may be the increased transit time of erythrocytes through the spleen due to reduced portal blood flow and/or increased fragility of red blood cells due to high levels of bile acids15. The similar hematobiochemical findings were also reported by Fuentealba et al.6. The findings of survey radiograph of the cranial abdomen were generally insignificant except hepatomegaly seen in 7 cases10,19. Hepatitis chiefly causes changes in the hepatic parenchyma and the standard lateral and ventro-dorsal radiographs of the cranial abdomen can be of use only for evaluation of liver size, margination, position and opacity11. Ultrasono- graphically, the hepatic parenchyma was hyperechoic in general (Fig. 4). Partington and Biller11 reported that increase in the liver echogenicity could be due to some toxic hepatopathies. The cytological findings in present study revealed marked degeneration and necrosis of hepatocytes along with neutrophilic infiltration, chronic hepatitis and several fibroblast cells, mild to moderate fatty changes in hepatocytes and few lymphocytes along with degenerated and necrotic hepatocytes, suggesting chronic or suppurative hepatitis20 (Fig. 5). The histopathology of USGB (N=3) cases in present study evinced multifocal chronic hepatitis characterized by congestion, focal haemorrhages, mild to moderate degenerative changes and fatty changes in hepatocytes along with fibrosis and mild mononuclear cell infiltration, chronic cholangiohepatitis, hyperplasia of biliary epithelium and marked thickening of capsule (Fig. 6). However, Fuentealba et al.6 found moderate to severe inflammatory infiltration, comprising principally of lymphocytes and plasma cells in the portal areas and extending into the midzone. The cytological/histopathological findings in the present study correlated well with the clinical, hematobiochemical and ultrasonographic findings. Radiography, however, proved to be of little value in the diagnosis of these diseases except that variation in size of liver like hepatomegaly can be diagnosed radiographically. Non-diagnostic sample (N=3) Three samples having hepatic affections by USGB (N=1) and USG-FNAB (N=2) were non diagnostic due to fragmentation of sample (USGB) or insufficient sample/poor staining. In the present study, USGB and USG-FNAB were found to be easy, safe, accurate, reliable and inexpensive techniques in the diagnosis of hepatic disease conditions in dogs.The free hand technique did not show any side effects. The techniques were practically effective in the differenatation of predominantly inflammatory (hepatitis) and degenerative (hepatosis) conditions of liver. Top ACKNOWLEDGEMENTS Authors are thankful to the Incharge, Clinical Diagnostic Lab and Head, Department of Veterinary Pathology for providing necessary facilities to carry out the present study. |
Top Figures | Fig. 1:: Sonogram showing hypoechoic liver parenchyma along with hyperechoic areas and tip of the needle (N) in the hepatic parenchyma during USGB.
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| | Fig. 2:: Cytology of liver showing mild to moderate fatty changes in hepatocytes in case of hepatosis. (Wright x100).
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| | Fig. 3:: Histopathology of the liver showing marked degenerative changes of hepatocytes and sinusoidal congestion (HE x40).
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| | Fig. 4:: Sonogram showing overall increase in echogenicity of liver parenchyma.
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| | Fig. 5:: Cytology of liver showing marked degeneration and necrosis of hepatocytes and neutrophils, suggesting suppurative hepatitis. (Wright x100).
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| | Fig. 6:: Histopathology of the liver showing chronic hepatitis characterized by mild fibrosis and mononuclear cell infiltration (HE x40).
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Tables | Table 1.: Hemato-biochemical parameters in cases of hepatosis (N=8).
| | Hematological parameters (Mean ± SE) | Biochemical parameters (Mean ± SE) | | Hb (× g/dL) - 8.10±1.54 | SGPT (μ/L) - 326.75±124.98 | | TLC (×103/μL) -48.19± 17.65 | SGOT (μ/L) - 148.75 ± 24.70 | | DLC (%) | AKP (μ/L) - 615.50± 164.45 | | N - 88.00±1.89 | BUN (mg/dL) - 31.21± 2.23 | | L - 9.75±1.79 | Creatinine (mg/dL) - 1.08± 0.12 | | E - 2.25± 0.96 | Total Protein (g/dL) - 6.54± 0.38 | | Albumin (g/dL) - 3.28± 0.29 |
| | | Table 2.: Hemato-biochemical parameters in cases of hepatitis (N=13)
| | Hematological parameters (Mean ± SE) | Biochemical parameters (Mean ± SE) | | Hb (× g/dL) - 7.32±0.63 | SGPT (μ/L) - 279.15±52.80 | | TLC (×103/μL) - 36.61± 8.82 | SGOT (μ/L) - 182.31 ± 42.13 | | DLC (%) | AKP (μ/L) - 556.38± 93.42 | | N - 90.77±1.32 | BUN (mg/dL) - 57.62± 17.62 | | L - 6.92±1.41 | Creatinine (mg/dL) - 3.05± 1.24 | | E - 1.85± 0.79 | Total Protein (g/dL) - 5.94± 0.45 | | M - 0.46±0.27 | Albumin (g/dL) - 2.87± 0.22 |
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| Hb-Haemoglobin, TLC-Total leucocyte count, DLC-Differential Leucocytecount, N-Neutrophils, L-Lymphocytes, E-Eosinophils, M- Monocytes, SGPT-Serum Glutamic Pyruvic Transaminase, SGOT- Serum Glutamic Oxaloacetic Transaminase, AKP-Alkaline Phosphatase, BUN- Blood Urea Nitrogen, p/L-micron per litre, g/dL- Gram per deciliter, mg/dL- miligrama per decilitre | |
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