Iron status and erythrocyte volume in dogs with congenital portosystemic vascular anomalies

Comparison of hematologic variables between dogs with congenital intrahepatic and extrahepatic portosystemic shunts

BACKGROUND

Dogs with congenital intrahepatic portosystemic shunt (IHPSS) are predisposed to gastrointestinal inflammation, ulceration, and bleeding, unlike dogs with congenital extrahepatic portosystemic shunt (EHPSS). Limited information is available about hematologic differences between dogs with IHPSS and dogs with EHPSS.

OBJECTIVE

Compare hemogram variables between dogs with IHPSS and EHPSS. We hypothesized that hematologic variables would differ between the 2 populations, with a higher frequency and severity of anemia and microcytosis in dogs with IHPSS.

ANIMALS

Twenty-six client-owned dogs with IHPSS and 35 client-owned dogs with EHPSS.

METHODS

Retrospective cross-sectional study. Dogs were included if a CBC was performed before shunt attenuation. Contingency analysis was performed to determine if the frequency of clinical signs and of hematologic variables below the reference range differed between groups. Hematologic and selected biochemical variables were compared between groups using an analysis of covariance with age as a covariate.

RESULTS

Gastrointestinal clinical signs (IHPSS, 81% vs EHPSS, 34%; P = .01), anemia (31% vs 6%; P = .01), microcytosis (77% vs 29%; P = .002), and hypochromia (77% vs 49%; P = .03) were more common in dogs with IHPSS than in dogs with EHPSS. Dogs with IHPSS had lower packed cell volume (34% vs 41%, P = .04), hemoglobin concentration (11.5 g/dL vs 13.7 g/dL, P = .03), mean corpuscular volume (57 fL vs 65 fL; P = .001), and mean corpuscular hemoglobin concentration (32 g/dL vs 33 g/dL; P = .04) than dogs with EHPSS.

CONCLUSIONS AND CLINICAL IMPORTANCE

Dogs with IHPSS had a higher frequency of anemia, microcytosis, and hypochromia and exhibited more gastrointestinal clinical signs.

Diagnosis and classification of portosystemic shunts: a machine learning retrospective case-control study

Diagnosis of portosystemic shunts (PSS) in dogs often requires multiple diagnostic tests, and available clinicopathologic tests have limitations in sensitivity and specificity. The objective of this study was to train and validate a machine learning model (MLM) that can accurately predict the presence of a PSS utilizing routinely collected demographic data and clinicopathologic features. Dogs diagnosed with PSS or control dogs tested for PSS but had the condition ruled out (non-PSS) were identified. Dogs were included if a complete blood count and serum chemistry panel were available from PSS diagnostic testing. Dogs with a PSS were subcategorized as having a single intrahepatic PSS, a single extrahepatic PSS, or multiple extrahepatic PSS. An extreme gradient boosting (XGboost) MLM was trained with data from 70% of the cases, and MLM performance was determined on the test set, comprising the remaining 30% of the case data. Two MLMs were created. The first was designed to predict the presence of any PSS (PSS MLM), and the second to predict the PSS subcategory (PSS SubCat MLM). The trained PSS MLM had a sensitivity of 94.3% (95% CI 90.1-96.8%) and specificity of 90.5% (95% CI 85.32-94.0%) for dogs in the test set. The area under the receiver operator characteristic curve (AUC) was 0.976 (95% CI; 0.964-0.989). The mean corpuscular hemoglobin, lymphocyte count, and serum globulin concentration were most important in prediction classification. The PSS SubCat MLM had an accuracy of 85.7% in determining the subtype of PSS of dogs in the test set, with variable sensitivity and specificity depending on PSS subtype. These MLMs have a high accuracy for diagnosing PSS; however, the prediction of PSS subclassification is less accurate. The MLMs can be used as a screening tool to increase or decrease the index of suspicion for PSS before confirmatory diagnostics such as advanced imaging are pursued.

Bone marrow iron scoring in healthy and clinically ill dogs with and without evidence of iron-restricted erythropoiesis

BACKGROUND

There are few reports in dogs that have evaluated the utility of semi-quantitative scoring of bone marrow iron stores in conjunction with reticulocyte hemoglobin (CHr) to identify iron-restricted erythropoiesis due to absolute iron deficiency or iron sequestration.

OBJECTIVES

An established system for scoring iron stores in human bone marrow samples was applied to dogs. The objectives were to evaluate interobserver agreement (Κ_ω ), determine marrow iron scores in dogs without detectable hematologic abnormalities, and assess combined interpretation of iron scores and CHr to evaluate for iron-restricted erythropoiesis.

METHODS

Four blinded observers independently scored iron in 139 Prussian blue-stained canine marrow samples from 0 (none) to 6 (very heavy), including healthy controls (n = 12), clinically ill dogs with (n = 100) and without (n = 16) detectable hematologic abnormalities, and dogs with experimental nutritional iron deficiency (n = 11). Additional medical record data were available for 118 dogs to evaluate for other evidence of iron deficiency (abnormal CHr, RBC indices, serum iron variables, external blood loss, or nutritional deficiencies).

RESULTS

Mean Κ_ω was 0.69 (substantial agreement) for all samples but was 0.44 (moderate agreement) for samples with iron scores <3, indicating distinguishing scores 0-2 may not be reliable. Dogs without detectable hematologic abnormalities had scores from 3-5. Dogs with scores <3 and decreased CHr often had more indicators of iron deficiency vs dogs only having low iron scores or low CHr.

CONCLUSIONS

Evaluation of dogs with marrow iron score <3 for external blood loss or nutritional deficiencies is likely clinically worthwhile, particularly if there is also decreased CHr.

Congenital Portosystemic Shunts in Dogs and Cats: Classification, Pathophysiology, Clinical Presentation and Diagnosis

Congenital portosystemic shunts (CPSS) are abnormal vascular communications between the portal and the systemic circulation, bypassing the hepatic parenchyma and resulting in liver hypoplasia and hepatic insufficiency. Such connections develop in utero and persist postnatally. CPSS are among the two most common congenital vascular anomalies of the liver in small animals, along with primary hypoplasia of the portal vein without portal hypertension (PHPV without PH). CPSS can be extrahepatic (ECPSS), most commonly diagnosed in small and toy breed dogs and cats, or intrahepatic (ICPSS), most commonly seen in large breed dogs. Single ECPSS is the most common type encountered in both dogs and cats. Clinical signs of CPSS are non-specific and may wax and wane, while laboratory findings can raise clinical suspicion for CPSS, but they are also not specific. Definitive diagnosis will be established by evaluation of liver function tests, such as determination of fasting plasma ammonia (FA) levels, and pre- and postprandial serum bile acids concentrations, and diagnostic imaging. The purpose of this article is to review the definition, classification, pathogenesis, clinical presentation, and diagnosis of CPSS in dogs and cats, highlighted by the authors' clinical experience.

Nasopharyngeal cryptococcosis in a cat: interlaboratory variation in cryptococcal antigen assay test results

Case summary

An indoor-only 6-year-old spayed female domestic cat was evaluated for a history of stertorous respiration. Skull radiographs revealed increased soft tissue density within the caudal aspect of the left nasal cavity. CT and rhinoscopy revealed a mass lesion in the choana, plus a smaller lesion, nearly completely occluding flow through the nasal passages. Rhinoscopy was used to collect a biopsy specimen from a fleshy, tan–yellow mass visualized in the caudal nasopharynx. Histopathology was diagnostic for Cryptococcus species infection and systemic antifungal therapy with fluconazole was initiated. Following a series of discordant results, serum samples were submitted to a veterinary diagnostic laboratory that utilized a cryptococcal antigen latex agglutination system with pretreatment of serum with pronase. Twenty-three months after the initial diagnosis, the cat’s serum cryptococcal antigen titer declined to 1:5 and the cat has responded well to continuing treatment.

Relevance and novel information

This case illustrates challenges associated with discordant test results for cryptococcal antigen among laboratories. Discordancies may be due to differences in assay design, or the underlying disease state itself, or whether serum is pre-treated with pronase; with some tests relying on the training and experience of the operator if the cryptococcal antigen detection test requires a subjective interpretation. It also resolves some confusion in the literature related to the assay types available and terminology used to describe them, and emphasizes the importance of considering cryptococcosis as an important differential for cats with upper respiratory signs, without nasal discharge, even if the cat is kept exclusively indoors.

Postattenuation neurologic signs after surgical attenuation of congenital portosystemic shunts in dogs: A review

The development of postattenuation neurologic signs (PANS) is a poorly understood and potentially devastating complication after surgical attenuation of congenital portosystemic shunts in dogs. Postattenuation neurologic signs include seizures but also more subtle neurologic signs such as depression, behavioral changes, tremors, and twitching. They most commonly occur within 7 days postoperatively and are typically unrelated to hyperammonemia, hypoglycemia, or electrolyte disturbances. This narrative review summarizes the findings of 50 publications from 1988-2020 that report occurrence of PANS. While most published reports included only dogs affected by postattenuation seizures (PAS), others included dogs with any form of PANS. Overall, PANS (including PAS) affected 1.6%-27.3% of dogs, whereas incidence of PAS ranged from 0%-18.2%. The etiology of PANS remains unknown; however, several theories have been proposed. Risk factors include preoperative hepatic encephalopathy, increasing age, and possibly certain breeds and extrahepatic shunt morphology. There is increasing evidence that prophylactic antiepileptic drugs do not prevent PANS. Treatment is centered around controlling neurologic signs with antiepileptic drugs and providing supportive intensive care. The 30-day survival rate in studies that included a minimum of four dogs affected by PANS was 0%-100% (median, 50.0%) and 0%-75.0% (median, 37.5%) for those with PAS. Mortality associated with PANS was typically related to occurrence of generalized seizure activity. Prognostic factors positively associated with short-term survival included having a history of preoperative seizures and development of focal seizures only. If affected dogs survived to discharge, survival for several years was possible, and the majority of neurologic signs manifested as part of the phenomenon of PANS appeared to resolve.

Variability in the cleavage of exosome-associated transferrin receptor questions the utility of clinically useful soluble transferrin receptor assays for dogs, cats, and horses

Whole transferrin receptor (TfR) is present in reticulocyte exosomes. Soluble transferrin receptor (sTfR) is cleaved from whole TfR in human plasma, with the remnant cytoplasmic domain (cTfR) remaining membrane associated. In humans, sTfR is a biomarker that can detect iron deficiency in the presence of inflammatory disease. This condition is still a diagnostic dilemma in veterinary species. We aimed to (1) confirm the presence of exosomes and exosome-associated TfR in the serum of dogs, cats, and horses; and (2) to assess and compare the proportion of cTfR to total (cTfR + whole) in exosomal membranes of healthy and diseased dogs and cats and in healthy horses to indirectly predict their anticipated levels of circulating sTfR. We used discarded serum and whole blood samples from canine and feline patients, separated into healthy and diseased groups based on the health status of each patient, and healthy equine participants from a previous study. Ultracentrifugation, followed in some experiments by OptiPrep discontinuous density gradient fractionation, was used to isolate exosomes. Exosomes and associated TfR were identified using TEM and Western blot for TfR, respectively. Densitometry tracings of Western blots of serum exosomes were used to measure the proportion of cTfR to total TfR. Extracellular vesicles compatible with exosomes were successfully isolated and expressed TfR. The proportion of cTfR in dogs was greater than 50%, indicating that a majority of the whole TfR was cleaved to produce sTfR (and remnant cTfR). There was significant interindividual variation and no significant difference between healthy and diseased animals. The proportion of cTfR in cats was very low at 11%, indicating that very little sTfR was likely produced. There was a small yet significant difference between healthy and diseased cats. Healthy horses do not appear to cleave exosome-associated TfR. Diagnosis of iron deficiency in the presence of inflammatory disease remains a challenge in veterinary medicine. Our results indicate that TfR is poorly or unpredictably cleaved in veterinary species, revealing that there are species differences in exosomal TfR handling. These data suggest that development of an assay for the detection and quantification of sTfR in the species investigated may not be warranted.

Use of video capsule endoscopy to identify gastrointestinal lesions in dogs with microcytosis or gastrointestinal hemorrhage

Background

Video capsule endoscopy (VCE) is a noninvasive imaging modality that can identify mucosal lesions not detected with traditional endoscopy or abdominal sonography. In people, VCE is used in diagnostic and management protocols of various gastrointestinal (GI) disorders, particularly in GI bleeding of obscure origin or unexplained iron deficiency anemia (IDA).

Objective

To evaluate the utility of VCE in the identification of mucosal lesions in dogs with evidence of GI hemorrhage.

Animals

Sixteen client‐owned dogs that underwent VCE.

Methods

Retrospective case‐control study. Medical records were reviewed to include dogs with microcytosis, low normal mean corpuscular volume, or clinical GI bleeding that received VCE.

Results

Median age of dogs was 8.7 years (range, 8 months to 15 years) with a median weight of 21.7 kg (range, 6.9‐62.5 kg). Abdominal ultrasound (16), abdominal radiography (4), and abdominal CT (1) did not identify a cause for GI blood loss. Gastric mucosal lesions were identified by VCE in 15 of 16 dogs and small intestinal lesions in 12 of 14 dogs, with 2 capsules remaining in the stomach. Endoscopy was performed in 2 dogs before VCE; 1 dog had additional small intestinal lesions identified through the use of VCE.

Conclusions and Clinical Importance

Video capsule endoscopy is a minimally invasive diagnostic tool that can identify GI lesions in dogs presenting with microcytosis with or without GI hemorrhage when ultrasonography is inconclusive; however, the majority of lesions identified would have been apparent with conventional endoscopy.

Interventional Radiology Management of Vascular Malformations: Portosystemic Shunts and Vascular Fistulae/Malformations

Vascular malformations are abnormal connections between blood vessels that can have various endothelial characteristics. Although uncommon, these malformations can present challenging diagnostic and therapeutic scenarios. The use of interventional radiology techniques in the management of various vascular malformations is an attractive option because of the ability to treat these malformations at the most appropriate anatomic location and in the most effective manner. Techniques such as coil embolization of intrahepatic portosystemic shunts and liquid embolization of arteriovenous fistulae/malformations have shown tremendous potential as treatments for these challenging diseases.

Haematology and coagulation profiles in cats with congenital portosystemic shunts

Objectives The objectives of this study were, first, to report the haematological parameters and coagulation times for cats with a congenital portosystemic shunt (CPSS) and the influence of surgical shunt attenuation on these parameters; and, second, to identify any association between prolongation in coagulation profiles and incidence of perioperative haemorrhage. Methods This was a retrospective clinical study using client-owned cats with a CPSS. Signalment, shunt type (extra- or intrahepatic), degree of shunt attenuation (complete or partial), haematological parameters, prothrombin time (PT) and activated partial thromboplastin time (aPTT) test results, and occurrence of any perioperative clinical bleeding complications were recorded for cats undergoing surgical treatment of a CPSS at the Royal Veterinary College, UK, between 1994 and 2011. Results Forty-two cats were included. Thirty-six (85.7%) had an extrahepatic CPSS and six (14.3%) had an intrahepatic CPSS. Preoperatively, mean cell volume (MCV) and mean cell haemoglobin (MCH) were below the reference interval (RI) in 32 (76.2%) and 31 (73.8%) cats, respectively. Red blood cell count and mean cell haemoglobin concentration (MCHC) were above the RI in 10 (23.8%) and eight (19.1%) cats, respectively. Postoperatively, there were significant increases in haematocrit ( P = 0.044), MCV ( P = 0.008) and MCH ( P = 0.002). Despite the significant increase in MCV postoperatively, the median MCV postoperatively was below the RI, indicating persistence of microcytosis. Preoperatively, PT was above the upper RI in 14 cats (87.5%), and aPTT was above the upper RI in 11 cats (68.8%). No cat demonstrated a perioperative clinical bleeding complication. Conclusions and relevance Cats with a CPSS are likely to present with a microcytosis, but rarely present with anaemia, leukocytosis or thrombocytopenia. Surgical attenuation of the CPSS results in a significant increase in the HCT and MCV. Coagulation profiles in cats with a CPSS are likely to be prolonged, irrespective of shunt type, but do not appear to be associated with an increased risk of clinical bleeding.

Hepatocutaneous syndrome in Shih Tzus: 31 cases (1996-2014)

OBJECTIVE

To characterize findings in Shih Tzus with progressive superficial necrolytic dermatitis and degenerative vacuolar hepatopathy consistent with hepatocutaneous syndrome.

DESIGN

Retrospective case series.

ANIMALS

31 Shih Tzus.

PROCEDURES

Medical records were reviewed to obtain information on signalment, history, treatment, outcome, and results of clinicopathologic testing, abdominal ultrasonography, and histologic examination of skin and liver specimens. A pedigree analysis was performed.

RESULTS

There were 16 males and 15 females. Median age at the time of diagnosis was 8 years (range, 5 to 14 years). Common clinical signs included lethargy, inappetence, weight loss, and lameness. Twenty-five dogs had cutaneous lesions consistent with hepatocutaneous syndrome; the remaining 6 initially only had hepatic abnormalities, but 3 of the 6 subsequently developed cutaneous lesions. Common clinicopathologic abnormalities included microcytosis (15/24 [63%] dogs) and high serum alkaline phosphatase activity (24/24 [100%] dogs). Hepatic ultrasonographic findings included a hyperechoic or heteroechoic appearance to the parenchyma with innumerable hypoechoic nodules. Histologic hepatic lesions consisted of degenerative vacuolar (glycogen and lipid) hepatopathy associated with minimally fibrotic to nonfibrotic, noninflammatory, proliferative nodules. Pedigree analysis confirmed a common ancestry in 12 of 18 dogs. Median survival time was 3 months (range, 1 to 36 months).

CONCLUSIONS AND CLINICAL RELEVANCE

Results suggested that HCS may have a heritable component in Shih Tzus, although the condition may also be identified in Shih Tzus without affected relatives. Clinical, clinicopathologic, ultrasonographic, and histologic abnormalities in affected Shih Tzus were similar to those previously reported for dogs of other breeds with HCS.

Hepatic hepcidin gene expression in dogs with a congenital portosystemic shunt

Background

Microcytic anemia is common in dogs with a congenital portosystemic shunt (cPSS) and typically resolves after surgical attenuation of the anomalous vessel. However, the pathophysiology of the microcytic anemia remains poorly understood. Hepcidin has been a key role in controlling iron transport in both humans and animals and in mediating anemia of inflammatory disease in humans. The role of hepcidin in the development of microcytic anemia in dogs with a cPSS has not been examined.

Hypothesis

To determine whether hepatic hepcidin mRNA expression decreases, while red blood cell count (RBC) and mean corpuscular volume (MCV) increase in dogs after surgical attenuation of a cPSS.

Animals

Eighteen client‐owned dogs with confirmed cPSS undergoing surgical attenuation.

Method

Prospective study. Red blood cell count (RBC) and mean corpuscular volume (MCV), together with hepatic gene expression of hepcidin, were measured in dogs before and after partial attenuation of a cPSS.

Results

There was a significant increase in both RBC (median pre 6.17 × 10¹²/L, median post 7.08 × 10¹²/L, P < .001) and MCV (median pre 61.5fl, median post 65.5fl, P = .006) after partial surgical attenuation of the cPSS. Despite the increase in both measured red blood cell parameters, hepatic gene expression of hepcidin remained unchanged.

Conclusions and Clinical Importance

This study found no evidence that dysregulated production of hepcidin was associated with anemia in dogs with a cPSS.

Association of increased erythrocyte osmotic resistance with haematological and histopathological findings in dogs with a congenital extrahepatic portosystemic shunt

The aim of the study was to investigate changes in erythrocyte osmotic resistance in relation to haematological and histological changes in dogs with a congenital portosystemic shunt. Osmotic fragility tests with complete blood counts and liver histological examinations were performed in 12 dogs with single extrahepatic portosystemic shunt confirmed by surgical exploration. Laboratory results were compared with those from 30 healthy dogs. Dogs with portosystemic shunt had a significantly increased erythrocyte osmotic resistance (P < 0.01) with 5%, 50% and 90% haemolysis corresponding to 0.45%, 0.35% and 0.30% NaCl solution, respectively. Statistical analyses revealed no correlation between haematological indicators and the osmotic fragility test results. Increased osmotic resistance was significantly associated with hepatic lipogranulomas. Based on these results, dogs with a congenital portosystemic shunt have a significantly increased erythrocyte osmotic resistance suggesting impaired red blood cell deformability. Osmotic resistance test that until now was not studied in canine hepatopathies seems to be independent of routinely performed haematological tests.

Shunting Between the CVC and Both the Azygos Vein and Thoracic Duct in a Dog with CTDS

A 5 mo old female rottweiler was referred for evaluation of a suspected congenital heart disease. Clinical signs included anorexia, exercise intolerance, and severe loss of body condition. Clinical examination revealed dyspnea, pale mucous membranes, and weak femoral pulses. Pleural and abdominal effusions and iron deficiency anemia were identified. A distended intrathoracic caudal vena cava (CVC) visible on thoracic radiographs suggested that the modified transudate abdominal effusion was the result of improper venous return to the right side of the heart. Cor triatriatum dexter (CTD) was diagnosed via echocardiography but did not explain all the anomalies detected during a contrast echocardiography. Abnormal communications between the CVC and azygos vein and the CVC and thoracic duct were subsequently identified by abdominal ultrasonography and angiography. Medical management with diuretics, iron supplements, and surgical treatment of CTD resulted in normalization of the respiratory rate, the exercise intolerance, and the anemia. To the authors’ knowledge, this is the first reported case of CTD associated with shunts between the CTV and both the azygos vein and thoracic duct in dogs. This report emphasizes the importance of presurgical assessment of concurrent thoracic and abdominal congenital vascular abnormalities.

Clinical and clinicopathologic abnormalities in young dogs with acquired and congenital portosystemic shunts: 93 cases (2003-2008)

OBJECTIVE

To determine whether clinical and clinicopathologic data could assist differentiation of congenital portosystemic shunts (CPSSs) from acquired portosystemic shunts (APSSs) in young dogs.

DESIGN

Retrospective case series.

ANIMALS

Dogs < 30 months of age with CPSSs (n = 62) or APSSs (31).

PROCEDURES

Medical records from 3 referral centers identified 31 dogs with APSSs and 62 dogs with CPSSs diagnosed from July 2003 to July 2008. Signalment, clinical signs, physical examination, and clinicopathological data were recorded, and statistical analyses were performed to determine differences between groups.

RESULTS

Univariable analysis showed APSS patients were older, heavier, and in poorer body condition, compared with CPSS patients. In CPSS patients, diarrhea was less prevalent, and neurologic signs were more prevalent. Ascites was more prevalent in APSS (Fisher exact test; OR, 50.2; 95% confidence interval [CI], 6.2 to 409.7), with no significant difference in albumin concentration between groups. The logistic regression model used to assess clinicopathological parameters showed lower Hct (OR, 1.42 × 10(-12); 95% CI, 1.42 × 10(-17) to 4.0 × 10(-6)), higher mean corpuscular volume (OR, 1.27; 95% CI, 1.08 to 1.50), and higher alanine aminotransferase concentrations (OR, 1.005; 95% CI, 1.001 to 1.009) were more likely in APSS patients.

CONCLUSIONS AND CLINICAL RELEVANCE

Several clinicopathologic differences between dogs with congenital and acquired shunts were identified; however, assessed alone, these would be unlikely to enable differentiation between the 2 conditions. Awareness of the rarity of ascites in CPSS cases should prompt recognition of a likely diagnosis of APSS, allowing the veterinarian to target further diagnostics and counsel the owner appropriately.

Portal hypertension: pathophysiology, diagnosis, and treatment

Portal hypertension (PH) is the result of increased vascular resistance in the portal circulation, increased portal venous blood flow, or both. In veterinary medicine, where portal pressure is seldom measured directly, the diagnosis of PH often is inferred from identification of associated complications including multiple acquired portosystemic shunts, ascites, and hepatic encephalopathy. Likewise, treatment of PH primarily is aimed at controlling these complications. The goal of this review is to provide an update on the pathophysiology, diagnosis, and treatment of PH. The review draws from information in the veterinary hepatology literature, reviews, and consensus statements in human hepatology and the literature on experimental models of PH.

Effect of storage on microcytosis observed in dogs with portosystemic vascular anomalies

Microcytosis is a common laboratory finding in dogs with iron deficiency and congenital portosystemic vascular anomalies (PSVA), however artefactual changes due to blood storage may occur which could mask this feature. This study evaluated the effects of storage on microcytosis in dogs with congenital PSVA. Full haematological parameters were measured on the day of sampling and following 24h storage at room temperature, in unaffected dogs (n=13) and in dogs affected with PSVA (n=24). Storage for 24h resulted in significantly higher MCV values in both groups of dogs (P<0.01). The percentage increase in MCV was greater in the control dogs (median 8.07%, range 5.64-9.31%) compared to affected dogs (median 6.05%, range 3.12-15.21%) (P<0.02). Storage of 1ml EDTA blood samples at ambient temperature for 24h prior to analysis, as occurs when samples are posted to external laboratories, will have significant effects on MCV and may mask microcytosis in dogs with PSVA.

Iatrogenic copper deficiency associated with long-term copper chelation for treatment of copper storage disease in a Bedlington Terrier

A 9-year-old Bedlington Terrier was evaluated because of weight loss, inappetence, and hematemesis. Copper storage disease had been diagnosed previously on the basis of high hepatic copper concentration. Treatment had included dietary copper restriction and administration of trientine for chelation of copper. A CBC revealed microcytic hypochromic anemia. High serum activities of liver enzymes, high bile acid concentrations, and low BUN and albumin concentrations were detected. Vomiting resolved temporarily with treatment, but the clinicopathologic abnormalities persisted. Results of transcolonic portal scintigraphy suggested an abnormal shunt fraction. Results of liver biopsy and copper quantification revealed glycogen accumulation and extremely low hepatic copper concentration. Serum and hair copper concentrations were also low. Chelation and dietary copper restriction were tapered and discontinued. Clinical signs and all clinicopathologic abnormalities improved during a period of several months.

Surgical treatment of intrahepatic portosystemic shunts in 45 dogs

The surgical attenuation of an intrahepatic portosystemic shunt in 45 dogs is described. Twenty-nine (64 per cent) had left divisional shunts consistent with a patent ductus venosus (PDV), 15 (33 per cent) had central divisional shunts and one had a right divisional shunt. In the dogs with a PDV, the shunt vessel could be most easily manipulated at a posthepatic site, whereas in those with central and right divisional shunts the manipulation could be more easily made intrahepatically but sometimes involved demanding intravascular surgical techniques. Eight dogs (18 per cent) died during the surgery or shortly afterwards. Of the 37 dogs surviving longer term, 28 (76 per cent) became clinically normal and required no medication or diet control. In a further three animals the shunt was ligated completely only during a second surgical procedure. The remaining six dogs were euthanased because of clinical signs of encephalopathy which were either surgically or medically uncontrollable.