Clinical history

A 3-year-old, 93 cm-long royal python (Python regius), weighing 2239 g, was presented with the following clinical signs of 10 days’ duration:

The snake was bred in an American snake farm and bought in a pet shop. Since then it was kept in a 120 cm × 50 cm × 60 cm sized, glass terrarium, lined with coco humus. A 70 watts spotlight was installed as the only light and heat source, which generated a constant temperature of 30°C during the day. The nocturnal temperature declined to 23°C and the air humidity was consistently over 60%. UV radiation was absent. The snake received rodents as food.

Physical examination

The snake was presented with a good body condition and an unimpaired general health. The mucous membranes of the oral cavity and pharynx appeared unsuspicious and pink coloured. In the cranial third of the body, approximately. 8 cm caudal to the occiput, an 8 cm long and 3 cm wide, tough-elastic, non-moveable swelling was present (Fig. 3.1). Nothing abnormal was detectable on the rest of the snake’s body by adspection and palpation. The righting reflex and the cloacal tone were normal. Survey radiographs were taken (Fig. 3.2) and ultrasonographic examination of the neck region was performed. In addition, a sonographically-controlled fine needle biopsy of the mass was taken.

Fig. 3.1 In the cranial third of the body of a royal python (Python regius), an 8 cm long and 3 cm wide, tough, elastic, non-moveable swelling was palpable.

Fig. 3.2 Radiographs of the ball python in the dorsoventral and latero-lateral planes. The swelling appeared as a homogeneous radiopaque mass similar to soft tissue.

Clinical diagnosis examination

Results

Please evaluate the clinical history, Figs 3.1 and 3.2, the results of the physical examination and clinical diagnosis laboratory tests.

2. List your differential diagnoses.

3. List your therapeutic strategy.

Differential diagnoses for swellings/distensions in snakes

Therapy

The snake was hospitalized to perform surgical removal of the mass. Previous to surgery the snake received premedication (Table 3.1).

Table 3.1 Therapy

After anaesthesia and analgesia, the skin around the swelling was disinfected with an alcoholic antiseptic. Incision of the skin was made between the second and third row of lateral scales and underlying muscle layers separated by blunt dissection. The mass (Fig. 3.3) was localized inside the oesophagus, which was incised to a length of 10 cm. The mucous membranes of the oesophagus were extensively infiltrated by the growth, so that a complete removal would have been impossible. As an extirpation was assumed to be connected with huge bleeding and tissue damage the animal was euthanized during surgery. Afterwards the greasy-mushy, strongly vascularized mass (Fig. 3.3) was removed and sent for histopathological examination.

Fig. 3.3 Left: skin incision between the second and third row of lateral scales and separation of underlying muscle layers by blunt dissection make the mass visible inside the oesophagus. Right: section of the greasy-mushy, strongly vascularized mass after surgical removal.

Histopathological diagnosis

The removed mass was histopathologically identified as a lymphoma. The malignant neoplasia included parts of necrosis and purulent-necrotic inflammation.

Discussion

Swellings or distensions of different causes are common findings in reptiles. A thorough diagnostic including imaging (radiography and/or ultrasound), cytology and/or histopathology is needed to reveal the cause. Sometimes these findings are neoplastic in origin. Most diagnoses are based on histopathological examinations following necropsies or biopsies. Classifications of the growths are done according to the WHO classification scheme of mammalian tumours. Current case reports and retrospective studies mentioned an increasing number of neoplasms diagnosed in reptiles over the last years. Among the reptiles, high tumour prevalence (12.4–15% in zoological collections) was described in snakes compared to a lower prevalence in lizards, tortoises and crocodiles. The ophidian genera Colubridae (colubrids), Crotalidae (pit vipers) and Viperidae (vipers) were more often affected than the genus Boidae (boids). Neoplasms in serpents were found frequently in liver, skin and the gastrointestinal tract. Epithelial tumours were diagnosed more often than mesenchymal tumours, and malignant neoplasms (54–80%) more often than benign neoplasms. Metastases were found in liver, pancreas, heart, spleen and lung. Besides mast cell tumours, lymphomas, seminomas and adenomas, a great variety of malignant neoplasms have been described in snakes (e.g. undifferentiated sarcomas of soft tissues, melanomas, carcinomas, spindle cell sarcomas, adenocarcinomas, haemangiosarcomas, sertoli cell tumours, malignant histiocytomas, fibrosarcomas and lymphosarcomas).

The diagnosed lymphoma is a cancer of lymphoid cells of the immune system. Lymphoid neoplasms are the most commonly reported tumours in snakes beside haematopoietic neoplasms. In retrospective studies, it seems to be most common in vipers, particularly cobras and urutus. Lymphoid tumours in reptiles are often multicentric and have blast morphology (only occasionally plasmacytoid or histiocytic morphology). The oral manifestations of lymphomas are often admixed with inflammation, like in the described ball python. Malignant lymphomas or lymphosarcomas are frequently accompanied by leukaemia and metastases. In this case, it was not possible to exclude a metastasis as the owner refused a complete necropsy of the python, but palpation and radiography gave no hint of this.

For therapy of cancers, there are only a few oncologic strategies reported in reptiles. Besides the surgical removal of neoplastic material, corticosteroids (prednisolone) and cytostatics (cyclophosphamide, chlorambucil, melphalan or doxorubicin) have been used occasionally for chemotherapy. The use of chemotherapeutics is controversial because their effectiveness and their tolerance differ a lot between species and between individuals.

Clinical history

A female Pearl island boa (Boa constrictor sabogae) weighing 1220 g was presented with the clinical signs of depression and intermittent anorexia. Due to the anorexia, the owner observed a reduced weight and growth. Since the animal was wild-caught, the exact age was unknown.

The animal had lived with the owner for 6 months. It was kept in a terrarium with temperatures of 28–34°C during the day and 22–26°C during the night. Relative humidity was 70–85%. The diet consisted of dead mice.

Clinical examination

On presentation, the animal was alert and had a body condition of 2/5. Adspection and palpation did not reveal any abnormal clinical signs.

Radiography (Fig. 3.4a, b)

1. What is your interpretation of the radiographic image in Fig. 3.4a, b?

Fig. 3.4 (a) Dorsoventral radiographic image of the lung of the boa constrictor; (b) latero-lateral radiographic image of the lung of the boa constrictor.

Clinical diagnosis laboratory

The results of the clinical diagnosis laboratory assays are shown in Tables 3.2 and 3.3.

Table 3.2 Haematology values of the boa constrictor

Table 3.3 Blood chemistry values of the boa constrictor

Results

Please evaluate the clinical history, Fig. 3.4a, b and the results of the physical examination and clinical laboratory diagnostic tests.

3. List your differential diagnoses.

Differential diagnoses

4. What would be your next diagnostic steps to ascertain the diagnosis?

Further diagnostic steps

In this case, endoscopic examination of the right lung was chosen. General anaesthesia was induced with butorphanol (1 mg/kg IM) followed by propofol (5 mg/kg IV), subsequently the animal was intubated and anaesthesia was maintained with isoflurane and intermittent positive pressure ventilation.

The images obtained are shown in Figs 3.5 and 3.6.

Fig. 3.5 Endoscopy of the right lung of the boa constrictor revealing a worm-like structure which was diagnosed as pentastomid.

Fig. 3.6 Endoscopy of the right lung of the boa constrictor revealing moderate haemorrhagic inflammation. On the right side, the intrapulmonary bronchus can be recognized.

5. What would be your therapeutic approach?

Therapy (Table 3.4)

Table 3.4 Therapy

Final diagnosis

Discussion

Pentastomidae are well-known parasites of reptiles, especially snakes. Typically, these parasites invade the lungs. The disease can be asymptomatic, but respiratory signs and even death have been noted. In this case, leucocytosis with azurophilia was observed. Increase of azurophils in reptiles is seen as a sign of inflammation, especially granulomatous inflammation. In the present case, significant inflammation was noted in the lung. Other clinical laboratory findings may include anaemia, eosinophilia and hypoproteinaemia.

Penstostomids usually have an indirect life cycle, but direct life cycles have also been found in certain species. Intermediate hosts typically include mammals such as rodents or primates. The latter also indicates a possible zoonotic risk of pentastomids. Due to the importance of an intermediate host, pentastomids are more frequently found in wild-caught reptiles, than in captive-bred animals. Treatment is controversial. The use of antiparasitic drugs, such as avermectins or levamisole, may kill the parasites. The risk that dead parasites in the lung may cause inflammation or obstruction of the trachea cannot be neglected. In the present case, endoscopic exploration of the right lung with mechanical removal of the parasites was successfully used. Postoperatively, the snake developed well and no complications were observed. The choice to investigate the right lung only was made on the basis that most snakes and boids, in particular, have a well-developed right lung, whereas the left lung is vestigial.

Clinical history

A 3-year-old female garter snake (Thamnophis spp.) was presented with the following clinical signs of 7 days’ duration:

The snake had changed ownership recently due to the inability of the previous owner to provide adequate husbandry. The snake had been treated with metronidazole for the past 7 days without improving.

Clinical examination

On presentation, the snake was in bad general condition (Figs 3.7 and 3.8). A moveable bulge cranial to the cloaca was palpable. A bluish tissue with a central lumen and a peripheral blind sac was detected by using a probe.

Fig. 3.7 Picture of the cloacal region of the snake.

Fig. 3.8 Picture of the bulge in the caudal quarter of the garter snake.

1. What is your interpretation of the clinical examination and Figs 3.7 and 3.8?

2. What are your differential diagnoses? List your diagnostic plan.

Differential diagnoses

Clinical diagnosis examination

Results

Therapy

It was decided to lavage the cloaca and the colon through the rectum with lubricant solution and massage the bulge caudally. A large amount of kidney beans were passed out (Fig. 3.9) but the massage induced intestinal prolapse (Fig. 3.10). This was corrected by placing transverse cloacal sutures (Fig. 3.11, Table. 3.5).

Fig. 3.9 Kidney beans were retrieved out of the intestines.

Fig. 3.10 Prolapsed intestine.

Fig. 3.11 Transverse cloacal sutures.

Table 3.5 Therapy

Final diagnosis

Discussion

Prolapse of the cloaca is generally the result of tenesmus. Constipation, bacterial enteritis and parasitic enteritis have been implicated. Constipation may be the result of environmental factors, such as excessively small enclosures inhibiting sufficient exercise to stimulate normal defecation. Determination of the cause of tenesmus and treatment of this, in conjunction with management of the prolapse, are important. In the acute phase, the prolapsed tissue is easily reduced and can be managed with either purse-string or transverse cloacal sutures. On questioning, the owner did not know the origin of the kidney beans. The snake was re-examined 6 weeks after surgery for suture removal and was presented in good health.

Clinical history

A 6-year-old female African egg-eating snake (Dasypeltis medici) weighing 110 g was presented with the following clinical signs:

Clinical examination

On presentation, the snake had a good body condition. It behaved motionless even when stimulated to move. The righting reflex was absent (Fig. 3.12). The palpation of the body was normal.

Fig. 3.12 Absent righting reflex of the egg-eating snake.

1. What are your differential diagnoses? List your diagnostic plan.

Differential diagnoses

Clinical diagnosis laboratory

The results of the clinical diagnosis laboratory assays were as follows:

The size of the snake was a limiting factor for further investigation. Blood collection was done by heart punction and the blood volume was so small that careful consideration was given to the type of diagnostic test to choose. Also biopsies of the liver and pancreas to examine IBD or cerebrospinal fluid analysis could not be made due to the size. Radiographs were assumed not to bring any further information. Ultrasonography, computed tomography and magnetic resonance imaging were not considered useful or practical.

2. List your therapeutic strategy.

Therapy (Table 3.6)

Within 5 days the snake’s general health got worse and so the decision was taken to euthanase it and to perform a thorough post-mortem examination.

Table 3.6 Therapy

Post-mortem findings

Final diagnosis

Discussion

Hepatic encephalopathy may cause CNS signs in reptiles, such as convulsions. Chronic liver disease is associated with weakness, weight loss and anorexia.

Clinical history

A 10-year-old female green iguana (Iguana iguana) weighing 2800 g was presented with the following clinical signs of one week’s duration:

The iguana was purchased when it was a hatchling and was kept in a large terrarium with adequate temperature gradient and adequate supplement of UV light. The diet of the lizard was based on fresh vegetables, commercial reptile food and insects.

Physical examination

On presentation, the iguana had a body condition of 2/5 and had thick saliva in the mouth and sunken eyes. Dehydration of 8% was estimated. Abdominal and rectal palpation showed ascites, gas-filled intestines and normal size kidneys.

Clinical diagnosis examination

Whole body radiographs were taken and blood samples were collected for haematology, blood chemistry and plasma protein electrophoresis.

Radiology (Fig. 3.13a, b)

1. What is your interpretation of the radiographs of Fig. 3.13a, b?

Fig. 3.13 (a) Ventrodorsal survey radiograph of a 10-year-old iguana with abdominal distension; (b) lateral survey radiograph of a 10-year-old iguana with abdominal distension.

Clinical diagnosis laboratory examination

The results of the clinical diagnosis laboratory assays are shown in Tables 3.7–3.9.

Table 3.7 Haematology values of the green iguana

Table 3.8 Blood chemistry values of the green iguana

Table 3.9 Plasma protein electrophoresis of the green iguana

Results

Please evaluate the clinical history, Fig. 3.13a, b, the results of the physical examination and clinical diagnostic tests.

3. List your differential diagnoses.

4. List your diagnostic strategy and possible diagnostic test.

Differential diagnoses

Diagnostic plan

More imaging techniques were necessary to discover the origin of the fluid-filled abdomen. The owner agreed to make an ultrasound study of the lizard.

Echography (Figs 3.14–3.17)

5. What is your interpretation of the ultrasound images of Figs 3.14–3.17?

Fig. 3.14 Ultrasound view of the congested liver and portal vein of the green iguana.

Fig. 3.15 Ultrasound view of the gall bladder of the green iguana notably distended. Measurements of this organ were taken.

Fig. 3.16 Ultrasound view of the right kidney of the green iguana.

Fig. 3.17 Ultrasound view of the spleen of the iguana.

Results of the ultrasound study

Therapy

Because the iguana blood results were strongly suggestive of a generalized infection, a treatment with a broad spectrum antibiotic was started and exploratory laparotomy was suggested to the owners to get a definitive diagnosis. After an IO catheter was positioned in the right femur, fluid therapy was started in order to correct the ionic imbalances discovered in the iguana (Table 3.10).

Table 3.10 Therapy

Surgery

The iguana was anaesthetized with an induction dose of alfaxolone 10 mg/kg. Rectal temperature, haemoglobin saturation, blood pressure and end tidal CO₂ concentration were monitored during the surgical procedure (Fig. 3.18). After paramedial incision, 100 ml of ascitic fluid was eliminated from the coelomic cavity (Fig. 3.19). The ascetic fluid contained lower glucose levels than peripheral blood suggesting active infectious peritonitis. Four structures compatible with neoplasia masses or bacterial granulomas were found attached to the intestinal meso and to the mesovary; the four structures were surgically removed (Fig. 3.20). An exceedingly enlarged gallbladder containing 50 ml of bile was found during the exploratory laparotomy (Fig. 3.21). The bile was removed using a 60 ml syringe and total cholecystectomy was carried out (Fig. 3.22). The liver lobe surrounding the gall bladder was resected as well in the same surgical procedure (Fig. 3.23). The laparotomy was closed using routinely described techniques and the lizard recovered from anaesthesia uneventfully.

Fig. 3.18 View of the iguana totally monitored prior to the surgical laparotomy. Blood pressure, haemoglobin saturation, rectal temperature and end tidal CO₂ were monitored during the surgical procedure.

Fig. 3.19 More than 100 ml of free fluid was removed from the coelomic cavity of the green iguana.

Fig. 3.20 Four structures resembling neoplasia or bacterial granulomas were found attached to the intestine and ovarian mesos. The four structures were removed during the surgery and submitted for histopathological analysis.

Fig. 3.21 Intraoperative view of the liver. The organ was pale and firm. On the left part of the image the gall bladder appears distended.

Fig. 3.22 More than 50 ml of bile were extracted from the gall bladder using a 60 ml syringe.

Fig. 3.23 The empty gall bladder and the attached liver lobe were removed surgically using standard procedures.

Biopsy findings

The four structures found in the lizard coelom were bacterial granulomas containing coccobacilli. The liver had chronic advanced cirrhosis, severe biliary hyperplasia and moderate multifocal fibrosis and moderate lipidosis and was an air sac carcinoma. Histopathology of the gall bladder showed severe diffuse necrosis of the mucosal layer, oedema and perilesional thrombosis.

Final diagnosis

Follow up

After 4 days of hospitalization, the iguana was sent home with antibiotic treatment for 2 weeks. Fourteen days after surgery the iguana was rechecked, including physical examination, blood analysis and ultrasound exam. There was still a raised WBC count and a small volume of intracoelomic fluid but the health status of the lizard was much improved. Posterior revaluation of the iguana 45 days and 3 months after surgery showed decreasing numbers of WBC to normality and decreased intracoelomic fluid. Bile acids were normal 2 weeks after surgery.

Discussion

Liver disease in iguanas has rarely been described in reptilian literature. Description of necropsies and specific infectious diseases such as viral infections have been reported but not from a practitioner’s point of view. This case describes the approach to liver disease in this iguana from a logical sequence of clinical procedures followed for other species. The author has not found any other report about cholecystectomy and liver lobe resection for green iguana in the scientific literature.