Liver lobe torsion is extremely uncommon in dogs, with few reports in the veterinary literature (1,6,11). Available reports have shown that this condition mainly occurs in middle- to older-aged dogs of a large breed, with no sex or underlying disease predispositions (15,20). The left and right triangular ligaments, left and right coronary ligaments, and falciform ligament provide spatial support to the liver (14,18). The left and right triangular ligaments provide support to the left and right lateral liver lobes until the muscular portion of the diaphragm, whereas the left and right coronary ligaments allow attachment of these lobes to the tendinous portion of the diaphragm (14). Damage or absence of these supporting structures can cause the liver lobe to twist at the vascular pedicle, initially causing venous occlusion, increased hydrostatic pressure, ascites, arterial and venous thrombosis, and eventually necrosis (18). In a report of 13 dogs with liver lobe torsion, only 3 cases had caudate lobe involvement without affecting the caudate process of the caudate lobe (15). Splenic torsion, which is characterized by the rotation of the spleen around the gastrosplenic and phrenosplenic ligaments leading to occlusion of venous drainage and arterial supply, is also rarely observed in dogs (3). Overall, previous studies have shown that this condition accounts for 0.5%-3.4% of all splenic conditions accordingly (8). Splenic torsion is often observed in conjunction with gastric dilatation and volvulus (GDV); however, studies have yet to determine how it occurs in an isolated manner (3,7). Clinical signs associated with torsion of these organs tend to be initially nonspecific, such as lethargy, abdominal pain and distension, weakness, anorexia, and vomiting, and could be acute or chronic (9,13,20). If undetected, this conduction may result in acute collapse and sudden death (3,15). This report aimed to describe our experience with the first ever reported case involving the simultaneous torsion of both the caudate process of the caudate liver lobe and spleen in dogs.

A 3-year-old, 20.6-kg, brown and black, neutered male German Shepherd dog, who received regular vaccinations and deworming, was referred to the Kyungpook National University Veterinary Medicine Teaching Hospital (KNUVMTH). After history taking, painless abdominal distension with chronic diarrhea having a waxing and waning course for 6 weeks was confirmed, which did not significantly improve despite 3 weeks of symptomatic treatment at the local animal hospital. No lethargy, anorexia, and vomiting were observed, and a weight loss of approximately 4 kg was noted during this period.

Upon presentation, the dog was bright, alert, and responsive with an estimated body condition score of 2/9. Physical examination findings, including temperature, pulse, respiration, auscultation, membrane mucous color, capillary refill time, and blood pressure were normal. Venous blood gas analysis and CBC revealed a normal acid-base balance, mild anemia, and a slight increase in leukocytes, particularly neutrophils, that had not been observed in the previous monitoring test (Table 1). A serum biochemistry analysis showed elevated ALT and AST levels and mild hypoalbuminemia (Table 2). The blood coagulation profile showed a slight increase in the citrate activated partial thromboplastin time (APTT), with a normal lactate level. During the fecal examination, the flotation test came back negative, although a large number of phagocyting neutrophils were observed on microscopy.

Table 1 . Perioperative blood gas analysis and completed blood count.

Parameters	Day –4	Day 0	POD 1	POD 3	POD 5	POD 7	POD 14	RR
pH		7.45	7.36					7.31-7.46
pCO2 (mmHg)		24	41.6					27-50
HCO3 (mmHg)		15.3	22.7					17-28
WBC (103/μL)	12.79	17.32	19.68	9.78	17.87	11.31	11.98	6-17
RBC (106/μL)	6.01	5.28	5.48	4.79	4.4	4.4	5.17	5.1-8.5
Hemoglobin (g/dL)	13.3	11.9	12.3	10.8	10.0	10.0	11.8	12.6-19.4
Hematocrit (%)	39.1	33.9	35.8	31.2	28.4	29.5	34.6	36.9-55.0
PLT (103/μL)	201	170	236	274	503	295	486	117-490
Neutrophil (103/μL)	10.37	14.0	17.46	6.74	15.14	9.14	8.8	3.6-12.5

RR, reference range; Day 0, reference day; POD, postoperative day..

Table 2 . Perioperative evaluation of serum biochemistry panels and blood coagulation profile.

Parameters	Day –4	Day 0	POD 1	POD 3	POD 5	POD 7	POD 14	RR
BUN (mg/dL)		19.9		5.8	8.2	8.3		9.2-29.2
Creatinine (mg/dL)		0.44	0.3	0.28	0.4	0.39		0.4-1.4
ALP (U/L)	114	249	223	358	330	296		47-254
ALT (U/L)	> 1000	1269	997	342	185	129		17-78
AST (U/L)	633	189	139	93	47	48		17-44
GGT (U/L)	6	6	6	6	7	8		5-14
Glucose (g/dL)		97	88		131	103		75-128
Albumin (g/dL)	2.6	2.3	2.0	1.9	2.1	2.1	2.6	2.6-4.0
Total protein (g/dL)	5.1	5.5		4.8	5.0	5.5	6.0	5.0-7.2
Total bilirubin (mg/dL)		0.3			0.2	0.2		0.1-0.5
Na+ (mEq/L)		148	144	149	147	144		141-152
K+ (mEq/L)		4.4	4.5	4.4	4.7	4.2		3.8-5.0
Cl– (mEq/L)		107	113	106	106	102		102-117
Lactate (mmol/L)		2.1	1					0.5-2.5
cPL (ng/mL)			< 50					< 50
Citrate PT (s)		17.6						14-19
Citrate APTT (s)		114.6						75-105

RR, reference range; cPL, canine pancreatic lipase; Day 0, reference day; POD, postoperative day..

Abdominal radiographs revealed a large amount of air in the gastrointestinal tract, which made evaluating other abdominal organs difficult due to intestinal gas (Fig. 1). On ultrasonography, the liver lobe thought to be the caudate lobe had heterogeneous echogenicity and an abnormal cranial orientation. No abnormal findings were noted in the other liver lobes. At the hilum of the affected liver lobe, the hepatic vessels could not be clearly distinguished, and a hyperechoic change in the adjacent mesenteric fat was observed (Fig. 2). On color-Doppler ultrasonography, the affected liver lobe did not exhibit a blood flow signal. Computed tomography (CT) revealed a triangular-shaped mass in the right upper abdomen (Fig. 3). Given that the caudate process of the caudate liver lobe was not observed and some branches originating from the hepatic vessels continued toward the margin of the mass, we believe that the mass was the caudate process of the caudate liver lobe. This liver lobe showed no contrast enhancement and was abnormally oriented cranially and medially, which should normally be oriented caudally. The splenic vessels showed a whirl sign in the counterclockwise direction at the splenic hilum (Fig. 4), with the slightly dilated splenic vein showing weak internal contrast enhancement. The spleen showed heterogenous contrast enhancement. In particular, the head of the spleen showed lower enhancement than did the splenic body and tail. In addition, the cranial mesenteric vein was somewhat dilated, and the distal parts of the small and large intestine were overall distended, but no structures that could cause obstruction were observed. Based on our imaging findings, the patient was diagnosed with torsion of the caudate process of the caudate liver lobe and spleen. This condition was considered an emergency, and surgical treatment was performed immediately.

Figure 1. Preoperative right lateral (A, B) and ventrodorsal (C, D) abdominal radiographs. A large amount of gas in the stomach and intestines was observed.

Figure 2. Preoperative B-mode (A, C) and color-Doppler (B, D) ultrasonography images of the caudate process of the caudate liver lobe (A, B) and their hilum (C, D). The caudate process of the caudate liver lobe had heterogeneous echogenicity (A) with no blood flow within the parenchyma (B, D). At the hilum of the affected liver lobe, hyperechoic mesenteric edema (asterisk) was observed, with no blood flow signal in the blood vessels (arrow) of the affected liver lobe (C). Other liver lobes had normal parenchyma and blood flow signals (C, D).

Figure 3. Preoperative dorsal plane pre-contrast (A), arterial (B), venous phase (C), and transverse plane arterial phase (D) computed tomography images. The caudate process of the caudate live lobe was abnormally oriented cranially and leftward (arrow heads). Small vessels branching to the affected liver lobe originating from the right hepatic vessels were observed (arrow), but the parenchyma show no contrast enhancement (D).

Figure 4. Preoperative venous phase transverse (A) and dorsal plane (B) and venous phase maximum intensity projection dorsal plane (C) computed tomography images. The splenic vein originating from the main portal vein was dilated and showed heterogeneous contrast enhancement (arrows) (A). The splenic parenchyma showed heterogeneous contrast enhancement (B). At the level of the splenic hilum, the splenic vessels ran counterclockwise, showing a whirl sign (arrow) (C).

Midazolam (0.2 mg/kg, Midazolam^®, Bukwang Pharm, Ansan, Korea) and fentanyl (3 μg/kg loading dose, Fentanyl Injection^®, Hanlim Pharm, Yongin, Korea) were injected intravenously (IV) as preanesthesia, after which anesthesia was induced with propofol (5 mg/kg, IV, Anepol Inj^®, Hana Pharm, Hwaseong, Korea). After intubation, anesthesia was maintained with isoflurane (1%-1.5%, Ifran^®; Hana Pharm, Seoul, Korea) in oxygen (2.0 L/min). Plasma solution was also administered at 5 mL/kg/h IV, and intraoperative analgesia was maintained with fentanyl (4-10 μg/kg/h, IV) via constant-rate infusion (CRI). A laparotomy was performed using a standard ventral midline approach and an additional bilateral paracoastal incision for surgical vision. Excessive gas in the gastrointestinal tract and intraperitoneal serosanguineous ascites were aspirated and suctioned, respectively. After confirming torsion and congestion of the caudate liver lobe, lobectomy of the affected tissues was performed using the Guillotine method with a 1-0 polyglactin (Vicryl^TM, Ethicon, United States). The resectioned lobes were dark red to black in color with no gross evidence of infection or neoplasia. Afterward, abdominal lavage was performed with 1,300 mL of warm 0.9% normal saline. A lesion suspected of focal ischemic injury was identified in the head of the spleen with torsion, suggesting that the gastrosplenic ligament, splenocolic ligament, and omentum were twisted around the splenic vein. The splenic vein was ligated, and splenectomy was performed using a harmonic scalpel. In addition, prophylactic gastric fixation was performed on the right paracoastal incisional line. Before suturing the abdomen, the abdominal cavity was flushed with 1,700 mL of warm 0.9% normal saline and closed routinely.

To overcome intraoperative hypotension, ephedrine (0.05 mg/kg twice, Ephedrine^®, Jeil Pharm, Daegu, Korea), dobutamine (5 μg/kg/min, IV CRI, Dobutamine Inj^®, Myung Moon, Hwaseong, Korea), norepinephrine (0.1 μg/kg/min, IV CRI, Norepirin^®, Huons, Jecheon, Korea), and 6% hydroxyethyl starch (Voluven^®; 2.5 mL/kg/h, IV CRI) were administered sequentially. Atropine (0.02 mg/kg IV) was used once for bradycardia. After surgery, bupivacaine (1.0 mg/kg, Bupivacaine HCl 0.5% Inj^®, Myung Moon, Hwaseong, Korea) was subcutaneously injected around the surgical site. Postoperative treatment consisted of analgesic management with fentanyl (2 μg/kg/h, IV CRI) and fluid therapy with plasma solution. A postoperative blood test revealed a normal lactate level, whereas a CBC showed mild anemia and leukocytosis (neutrophilia) typically observed after surgery (Tables 1, 2). Regarding significant changes in serum chemistry analysis, liver enzyme (ALT and AST) levels were still high, although the albumin level decreased to 1.9 g/dL (reference range: 2.6-4.0 g/dL). Immediately after surgery, vital parameters showed normal values except for temperature (33.6°C), which eventually elevated to normal levels within an hour. Clinical signs, including chronic diarrhea and flatulence, gradually ameliorated over around 5 days, together with the normalization of laboratory parameters. Similarly, radiography showed a decrease in gastrointestinal dilatation, and the patient was discharged 11 days after surgery without complications. No chronic diarrhea and additional torsion were observed during the follow-up examination after approximately 6 months.

Torsion of the caudate process of the caudate liver lobe and spleen, which rarely develops in dogs individually, occurred simultaneously in a 3-year-old, neutered male German Shepherd dog. After ultrasound examination upon presentation, torsion of the caudate liver lobe was suspected; however, other than abdominal distension and diarrhea, no other clinical signs that required emergency treatment, such as hemoabdomen or acute collapse, had been observed (10). As such, we opted to perform CT for a more sensitive non-invasive diagnostic option, which subsequently confirmed liver lobe torsion while also incidentally discovering splenic torsion. Diagnostic imaging, including ultrasound and CT, played an important role in providing vital disease information by assessing and characterizing the patient’s condition (9,12).

Although the cause of liver lobe and spleen torsion in dogs is not clearly known, the absence of structures supporting the organs or damage to these supporting structures caused by trauma or tumors have been proposed to cause torsion (11,16,20). Additionally, excessive gas distension in the gastrointestinal tract, like GDV and flatulence, has been considered a potential risk factor given that it impairs the support mechanisms of the liver and spleen (5,6,15). In particular, GDV has initially been considered to cause torsion of the left hepatic lobe by promoting laxity of the left triangular ligament; however, studies later confirmed that it was not associated with torsion of the right hepatic lobe (3,4,15). The left hepatic lobe is most prone to torsion considering its potential for laxity of the hepatogastric ligament, its relatively large size and high mobility compared to the right hepatic lobe, and its anatomical separation from other hepatic lobes (18). However, these characteristics do not explain the lower occurrence of torsion in other hepatic lobes than in the left hepatic lobe (2,11). In the current case, torsion of the caudate liver lobe and spleen occurred concurrently with excessive gas expansion in the gastrointestinal tract. Therefore, the torsion in our case could have been attributed to the compression or damage of the supporting structure of the liver lobe or spleen caused by severe gas expansion in the gastrointestinal tract or the mutual effects of the occurrence of torsion between the liver lobe and the spleen.

Given that liver masses with loss of vitality in dogs with hepatic torsion can be similar in ultrasonographic appearance to tumor tissue, histological examination and prognosis evaluation is necessary to rule out tumors (20). The most reported histopathological findings in dogs with liver torsion include parenchymal necrosis and atrophy and local accumulation of neutrophils in the affected tissue (18,20). In the current case, intraoperative macroscopic evaluation revealed congestion and atrophy of the affected lobe without heterogeneous structures suggestive of a tumor. In addition, no macroscopic findings indicating tumors were observed in other liver lobes or organs, and the possibility of tumors was low considering the age of the patient. Lastly, excised tissues were not further submitted for histopathology due to the owner’s financial difficulties.

Clinical symptoms of hepatic lobe and splenic torsion in dogs are mainly nonspecific, with available studies reporting abdominal pain, lethargy, anorexia, and vomiting (3,6,15). However, this patient showed only abdominal distension and chronic diarrhea, with no other specific clinical findings or significant changes in laboratory parameters during the previously symptomatic treatment period of around 3 weeks. Given that the chronic diarrhea and gas expansion in the gastrointestinal tract that did not respond to medical treatment were treated after surgical resection of the affected necrotic organ with torsion, the relationship between organ torsion and the previously mentioned clinical symptoms should be considered.

Controversial reports have suggested an increase in the incidence of GDV after splenectomy or hepatectomy in dogs (11,19). However, considering that the spleen and part of the liver lobe had been removed simultaneously in the current case, a substantial amount of space had been created in the cranial abdomen, which allows greater movement of the remaining organs and consequently increases the risk of new torsion. Therefore, based on the medical history and surgical findings, prophylactic gastric fixation was performed. According to previous reports, immediate surgical intervention in cases involving liver and spleen torsion can promote good outcomes (13,15,17). The current patient also showed an improvement in clinical symptoms through immediate stabilization after diagnosis, resection of the affected liver lobe and spleen, gastric fixation, and proper management after surgery. No significant findings were noted during the follow-up examination 6 months after surgery.

To our knowledge, this has been the first report on the concomitant torsion of the caudate process of the caudate liver lobe and spleen in a dog. Despite their rarity, liver lobe and splenic torsion in dogs can be considered in the differential diagnosis list for cases with untreated chronic diarrhea and excessive abdominal distension. More research of related cases is needed to evaluate the causal relationship between these pathological conditions in dogs and comprehensively analyze the clinical symptoms and etiology.

The authors have no conflicting interests.