Erythrocyte volume distribution analysis and hematologic changes in dogs with iron deficiency anemia

Impact on canine neutrophil preservation with the addition of bovine serum albumin to K3 -EDTA whole blood samples

BACKGROUND

Cellular deterioration occurs with blood sample aging, impacting white blood cell (WBC) identification and differential accuracy. This may be exacerbated in samples from patients experiencing inflammation. Previously, bovine serum albumin (BSA) has been shown to improve cellular preservation of blood and other samples, but the effect on cell preservation in canine blood has not been assessed.

OBJECTIVES

We aimed to determine the effects of BSA on neutrophil nuclear area when added to potassium ethylene diamine tetra-acetic acid (K3 -EDTA)-anticoagulated canine blood prior to blood smear preparation. We evaluated the impact of inflammatory leukograms, sample storage temperatures (4° and 20°C), and time on outcomes.

MATERIALS AND METHODS

Canine K3 -EDTA-anticoagulated blood samples stored at 4° and 20°C were used from unique patients, 10 with and 10 without inflammatory leukograms. Blood smears were prepared from aliquots with or without the addition of 22% BSA at 0, 4, 8, 24, 48, and 72 h. The nuclear area was measured for 25 randomly selected neutrophils per slide using Fiji software. Mixed-effect linear regression modeling was performed (significance: P < 0.05).

RESULTS

Nuclear area increased over time with and without added BSA. Both sample storage temperatures and the presence or absence of an inflammatory leukogram significantly impacted neutrophil nuclear area. Samples with added BSA had slightly higher predicted nuclear areas than those without BSA, but this difference was not statistically significant.

CONCLUSIONS

BSA did not significantly impact neutrophil nuclear area and did not improve neutrophil preservation in canine blood samples.

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.

Histograms of Complete Blood Counts in Dogs: Maximizing Diagnostic Information

Histograms, which are an integral part of the automated complete blood count, are now available through most of the automatic hematology analyzers used in veterinary clinical practice. Data concerning the size and number of blood cells are graphically presented in histograms, and their variations are also illustrated. Important information that is not apparent from numerical results are sometimes provided by histograms. Histograms are also referred to as frequency distribution curves and are essentially graphs resulting from the placement of the sizes of cells on the x-axis and the number of cells on the y-axis. Typically, automated analyzers provide histograms for each class of blood cells, that is, for erythrocytes, leukocytes, and platelets. Thus, when the erythrocyte histogram shows asymmetry with a right shift, it means the size of the erythrocytes is greater than normal (macrocytosis); when it presents a left shift, the size of the erythrocytes is less than normal (microcytosis). When two peaks are found in the curve, two populations of erythrocytes coexist, as in the case of a blood transfusion or therapeutic response. In the leukocyte histogram, three peaks are found: the closest to the y-axis (left) corresponds to the lymphocytes, the middle to the monocytes, and the right to the polymorphonuclear cells (neutrophils, eosinophils, and basophils). Finally, in platelet histogram, asymmetry with a right shift suggests the presence of giant platelets or schistocytes. Although the histogram is not recommended as a stand-alone test, it allows the practitioner to observe abnormalities in the distribution curve that correspond to abnormalities in the size or number of cells, and to quickly make diagnostic or therapeutic decisions that are particularly important in emergencies.

A review of anaemia of inflammatory disease in dogs and cats

Anaemia of inflammatory disease is a common cause of anaemia in routine veterinary practice. It is most often mild to moderate, normocytic, normochromic and non-regenerative. Shortened red cell life span, inhibition of iron metabolism and impaired bone marrow response to erythropoietin all contribute to its development. Although anaemia of inflammatory disease is a well-known cause of anaemia in dogs and cats, there is a lack of epidemiological information because specific diagnostic criteria have not been established in veterinary species. Anaemia of inflammatory disease is associated with a poor outcome in various disease states in human medicine; however, its clinical significance and treatment in veterinary medicine are not well understood. This review article describes anaemia of inflammatory disease in dogs and cats and considers its potential significance.

Iron Homeostasis and Disorders in Dogs and Cats: A Review

Iron is an essential element for nearly all living organisms and disruption of iron homeostasis can lead to a number of clinical manifestations. Iron is used in the formation of both hemoglobin and myoglobin, as well as numerous enzyme systems of the body. Disorders of iron in the body include iron deficiency anemia, anemia of inflammatory disease, and iron overload. This article reviews normal iron metabolism, disease syndromes of iron imbalance, diagnostic testing, and treatment of either iron deficiency or excess. Recent advances in diagnosing iron deficiency using reticulocyte indices are reviewed.

Hematologic responses in llamas with experimentally-induced iron deficiency anemia

Hematologic abnormalities consistent with iron deficiency anemia were experimentally induced in two healthy llamas by repeated phlebotomy. Hematologic abnormalities included erythrocyte microcytosis and hypochromia, decreased hemoglobin concentration, hypoferremia, and decreased transferrin saturation. Erythrocyte volume distribution histograms were more sensitive than mean corpuscular volume values for detection of microcytosis. Hypochromia, which was often eccentric, was morphologically observed on Wright-Giemsa-stained blood films. Frequent folded erythrocytes and dacryocytes were also noted on the blood films. Hematologic abnormalities resolved rapidly after cessation of blood removal, without parenteral iron supplementation.

Predicted mean corpuscular volume as an indicator of bone marrow iron in anemic dogs

A predicted mean corpuscular volume (PMCV) was calculated from the reticulocyte percentage and compared to the actual mean corpuscular volume for the purpose of determining bone marrow iron depletion in the dog. A difference of greater than 10 fl between the pMCV and the actual measured MCV accurately predicted the absence of stainable iron in bone marrow aspirates (sensitivity 86%, specificity 93%). The difference (Diff) between the predicted and actual measured MCV may also be a valuable method for following response to iron therapy in dogs with iron deficiency anemia without the necessity for repeated bone marrow examination. The predicted MCV may be useful in determining which patients are not at risk for canine iron deficiency.

Evaluation of the erythroid regenerative response in two different models of experimentally induced iron deficiency anemia

Anemia was induced in weanling Sprague Dawley rats either by feeding an iron-deficient diet or by chronic phlebotomy. The erythroid regenerative response was then evaluated before and after a hemolytic event, and results were compared with those of a third group of control nonphlebotomized rats fed an iron-replete diet. Diet and phlebotomy groups developed a similar degree of anemia (mean hemoglobin concentration 7.9 g/dL and 7.8 g/dL, respectively; controls, 13.9 g/dL) and hypoferremia (mean serum iron concentration 25.4 microgram/dL and 34.9 microgram/dL, respectively; controls, 222.0 microgram/dL). However, the anemia in diet rats was nonregenerative (reticulocyte count, 83.1 X 10(3) cells/microliter) and associated with bone marrow erythroid hypoplasia; whereas the anemia in phlebotomy rats was regenerative (reticulocyte count, 169.6 X 10(3) cells/microliter) and associated with bone marrow erythroid hyperplasia. Thrombocytosis was seen in diet rats (1,580 X 10(3) cells/microliter) but not phlebotomy rats (901 X 10(3) cells/microliter) when compared with controls (809 X 10(3) cells/microliter). To further evaluate the regenerative capability, phenylhydrazine (PHZ) was administered to induce hemolysis. Erythrocyte mass declined approximately 25% in all groups, including controls. The reticulocytosis (265.3 X 10(3) cells/microliter) seen in phlebotomy rats was earlier and significantly greater than that seen in either diet or control rats. Hemoglobin concentration returned to pre-PHZ concentrations (7.9 g/dL) in phlebotomy rats within 4 days posthemolysis. In diet rats, the maximal regenerative response (176.3 X 10(3) cells/microliter) was not seen until 8 days posthemolysis, and hemoglobin (7.5 g/dL) did not return to pre-PHZ concentrations during the 8-day study. In many aspects, the anemia seen following diet- or phlebotomy-induced iron deficiency was similar. However, the erythroid regenerative capability varied depending on the mechanism by which anemia was induced and furthermore altered the efficiency of hemoglobin production following a hemolytic event. These results suggest that the availability of iron in the diet may modulate the pathogenesis of iron deficiency anemia.

Differentiation of dogs with regenerative and non-regenerative anaemia on the basis of their red cell distribution width and mean corpuscular volume

The red blood cell distribution width (RDW), which provides a quantitative measure of the heterogeneity of the red cell population (anisocytosis) in the peripheral blood, the mean corpuscular volume (MCV) and a regression model combining both variables were used to assess their predictive accuracy in differentiating 51 dogs with regenerative anaemia from 92 dogs with non-regenerative anaemia, which had been diagnosed on the basis of the corrected reticulocyte count A classification tree analysis was constructed to generate an optimum set of diagnostic rules to differentiate between the two types of anaemia. Seventy-four dogs with a normal haemogram were used as controls. An increase of 1 per cent in the RDW and of 1 fl in the MCV increased the odds of an anaemic dog suffering from regenerative anaemia by factors of 1.3 and 1.14, respectively. By the classification tree, 78 per cent of anaemic dogs with a RDW of 16.25 per cent or less would be expected to have non-regenerative anaemia. With a RDW over 16.25 per cent, an MCV of 68.2 fl was the cut-off between dogs expected to have regenerative (71 per cent) or non-regenerative (75 per cent) anaemia. The RDW and MCV are measured by most automatic haematology analysers and may give the first indication of the bone marrow response of an anaemic dog. However, different electronic counters give different normal values of the RDW and MCV.

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

Microcytosis, hypochromasia, and low mean corpuscular hemoglobin are frequent hematologic abnormalities in dogs with portosystemic vascular anomalies (PSVA). The relationship of iron status to these abnormalities is unclear. We evaluated iron status and hematologic and biochemical parameters in dogs with congenital PSVA before (25 dogs) and after (11 dogs) partial ligation of the vascular anomaly. Serum iron concentration and total iron binding capacity were subnormal in 56% and 20% of dogs with PSVA, respectively. Transferrin saturation was normal in 68%, decreased in 20%, and increased in 12% of the dogs. Plasma ferritin concentration was either normal (56%) or high (44%), and was not associated with increases in ceruloplasmin concentration. Hepatic stainable iron was increased in 10 of 16 dogs. Mean corpuscular volume (MCV), mean corpuscular hemoglobin, and mean corpuscular hemoglobin concentration were decreased in more than 60% of dogs with PSVA. Serum biochemical abnormalities included high bile acid concentration and alanine transaminase (ALT) and alkaline phosphatase (ALP) activities; and low urea, creatinine, cholesterol, and total protein concentrations. Serum iron concentration and clinical status (normal or PSVA) significantly influenced MCV (P = .003 and P < .001, respectively), whereas age, ceruloplasmin, ferritin, cholesterol, bile acids, and total iron binding capacity did not. Partial ligation of PSVA was associated with resolution of clinical signs and the return to normal of iron status and all clinicopathologic abnormalities, except total fasting bile acid concentrations. These findings indicate that iron status is frequently abnormal in dogs with PSVA and that low serum iron concentration appears to be related to the development of microcytosis. The normalization of iron status and clinicopathologic abnormalities after treatment suggests that they are direct consequences of PSVA.

Hematology and hemostasis in the horse: normal functions and common abnormalities

In diseased animals, laboratory evaluations of erythrocytes, leukocytes, and hemostasis provide important information that contributes to either narrowing the list of potential diagnoses or to determining a specific diagnosis. To adequately interpret the results of these evaluations, normal erythrocyte and leukocyte kinetics and normal hemostatic function must be understood. In addition, knowledge of common diseases resulting in abnormalities of these laboratory tests and of typical changes in these tests caused by these diseases is vital. This article has reviewed normal erythrocyte and leukocyte kinetics and normal hemostatic functions that are clinically significant and has described the laboratory abnormalities expected in common diseases affecting these functions.

Microcytosis and iron status in dogs with surgically induced portosystemic shunts

Microcytosis is common in dogs with congenital portosystemic shunts (PSS) and acquired liver disease. The objective of this study was to determine if microcytosis could be induced in normal dogs by surgical creation of PSS, and to characterize the changes in hematology and iron status. Hematocrit, mean cell volume, mean cell hemoglobin, and mean cell hemoglobin concentration decreased linearly from 45.5%, 69.1 fL, 22.8 g/dL and 33.1% to 39.5%, 55.9 fL, 17.8 g/dL and 31.9%, respectively, 18 weeks after creation of PSS. The erythrocyte count did not change, but red cell distribution widths indicated a shift to a heterogenous population with decreased volume. Mean cell volume and mean cell hemoglobin decreased rapidly after induction of PSS and were significantly (P < .05) different from presurgery values within 2 weeks. Serum iron and copper concentrations and total iron binding capacity were decreased in dogs with PSS. Liver iron concentration doubled after creation of PSS, with the majority of stainable iron located in Kupffer cells. The changes in erythrocyte indices and measures of iron status in dogs with surgically induced PSS were similar to those in dogs with congenital PSS. Microcystosis developed rapidly in dogs after induction of PSS. These results indicate that iron deficiency was not the cause of microcytosis in these dogs.

Effects of aerobic long distance running training (up to 40 km.day-1) of 1-year duration on blood and endocrine parameters of female beagle dogs

The effects of long distance running training on blood parameters, hormone responses and bone growth were studied in young growing dogs. A genetically uniform group of female beagles matched with respect to age and body mass were used. The runner dogs (n = 10) underwent gradually increased running exercise up to 40 km.day-1 on a treadmill with 15 degrees uphill gradient 5 days each week during a period of 1 year, while the littermate control dogs (n = 10) were kept in their cages throughout the study. Low plasma lactate concentrations of the runners measured immediately after the running training indicated the aerobic metabolism of the dogs while running. Significant decreases of blood haemoglobin concentrations (11%), blood erythrocyte number (10%), and erythrocyte packed cell volume (12%) were found in the runner group. Throughout the experiment, the value of thyroxine was slightly lower (13%) in the runners but no changes were found in tri-iodothyronine, free thyroxine, or cortisol serum concentrations. Serum oestradiol concentration at 56 weeks was significantly lower (42%) in the runner group than in the control group but was not as low (27%) at 70 weeks. Somatomedin-C concentration had decreased significantly by 37% at the age of 56 weeks in the runner group but was again at the level of the control dogs at the end of experiment (at 70 weeks). Ulna and radius bone mass as a ratio to the body mass had significantly increased in the runners. It would seem from our study that long distance running has a positive effect on bone growth.(ABSTRACT TRUNCATED AT 250 WORDS)

Hematologic features of iron deficiency anemia in llamas

Iron deficiency anemia was identified and characterized in three 14 to 29-month-old male llamas (llama Nos. 1-3) from separate herds in Colorado. The identification of iron deficiency anemia was based on hypoferremia (serum iron = 20-60 micrograms/dl), erythrocytic features, and hematologic response to iron therapy. The anemia was moderate and nonregenerative and characterized by erythrocyte hypochromia, microcytosis (mean cell volume = 15-18 fl), and decreased mean corpuscular hemoglobin concentration (36.0-41.0 g/dl). Morphologic features unique to llamas with iron deficiency anemia included irregular distribution of hypochromia within erythrocytes and increased folded cells and dacryocytes. The cause of iron deficiency was not determined. The llamas were treated with various doses and schedules of parenteral iron dextran. Two of the llamas were monitored for up to 14 months after the start of iron therapy and experienced increases in hematocrit and mean cell volume values. In one llama, progressive replacement of microcytic cells with normal cells was visualized on sequential erythrocyte volume distribution histograms following iron therapy.

Dyserythropoiesis, polymyopathy, and cardiac disease in three related English springer spaniels

A polysystemic disorder was observed in three related English Springer Spaniel dogs that demonstrated regurgitation from an early age, slowly progressive temporal muscle atrophy with partial trismus, and less pronounced generalized skeletal muscle atrophy. All dogs exhibited moderate dyserythropoietic anemia, polymyopathy with megaesophagus, and varying degrees of cardiomegaly. The prevalence, etiology, underlying pathomechanism, and possible mode of inheritance remain to be elucidated.

Gastrointestinal lymphoma in 20 dogs. A retrospective study

The records of 20 dogs with histopathologically diagnosed gastrointestinal (GI) lymphoma (LSA) evaluated between 1970 and 1984 were reviewed. Fifteen dogs were considered to have primary GI LSA, while five dogs had GI involvement in association with the multicentric form. Most clinical and laboratory findings were nonspecific, but positive-contrast upper GI radiography was suggestive of GI LSA in all of the dogs evaluated. Nine dogs had extensive lymphocytic-plasmacytic inflammatory infiltrates around the neoplastic foci, resulting in difficulty in obtaining a diagnosis of GI LSA when samples were obtained by endoscopy.