Managing severe anaemia with a blood transfusion in a suspected IMHA case

This article discusses from initial presentation, stabilisation and treatment then relapse, a challenging case with an inconclusive diagnosis and differentials of hemangiosarcoma or immune-mediated haemolytic anaemia. The case progression included intensive medical management and a whole-blood transfusion with an excellent outcome.

Hemangiosarcoma

Hemangiosarcoma is a common canine neoplasia with a higher prevalence in neutered animals than entire (Robinson et al, 2020). Superficial cutaneous lesions may be excisable while organ tumours are often fatal. However, advances in treatment have been minimal (Kim et al, 2015) and metastasis is common. Symptoms of visceral, often splenic, masses can include: anorexia, lethargy, weakness, cachexia, dyspnoea, syncope, pallor, increased capillary refill time, dehydration, peripheral hypotension, cold limbs, emesis, diarrhoea and hyperthermia (De Nardi et al, 2023). These ambiguous symptoms may resolve and recur frequently during illness due to small ruptures from malformed vessels intermittently leaking in the tumour, then clotting (Kim et al, 2015). Tumour rupture, however, causes haemoabdomen, hypovolemic shock, arrhythmias, respiratory arrest and sudden death (De Nardi et al, 2023).

Immune-mediated haemolytic anaemia

In haemolytic anaemia, red blood cells are destroyed prematurely, causing anaemia. Patients often present with inflammation, necrosis and thrombosis, hyperbilirubinaemia, reticulocytosis, macrocytosis and anisocytosis (Idalan et al, 2023), lethargy, weakness, vomiting, diarrhoea, pale or yellow gums, collapse, discoloured urine and petechiae (Johnson, 2020). Usually immune-mediated haemolytic anaemia blood smear examination displays persistent autoagglutination and marked spherocytosis with a positive Coombs test, which are not all present in other hemolytic conditions (Idalan et al, 2023) (Figure 1). Although spherocytes are only visible in 67–94% of cases and are not specific to immune-mediated haemolytic anaemia, they are an excellent marker for the disease (Johnson, 2020). Immune-mediated haemolytic anaemia is one of the most common immune-mediated diseases diagnosed in dogs and has a 30–70% mortality rate despite treatment, and relapse rates are between 11–15%. Even after recovery from the initial crisis, the long-term risks include thromboembolism, renal or liver failure, disseminated intravascular coagulopathy, relapse or medication complications (Balch and Mackin, 2007; Johnson, 2020; Palin, 2021). For this reason, close monitoring and ongoing re-examinations are necessary (Palin, 2021). Males have a statistically worse prognosis, although the disease is seen more commonly in females. If the haemolysis is intravascular, the additional risk of disseminated intravascular coagulopathy, thromboembolic and coagulopathies requires more aggressive treatment than with extravascular haemolysis (Johnson, 2020). Immune-mediated haemolytic anaemia can be primary or idiopathic, secondary to infection, toxin, certain drugs and neoplasia (Garden et al, 2019; Johnson, 2020). In total, 30% of immune-mediated haemolytic anaemia cases are non-regenerative on presentation, and in regenerative cases it takes 4–5 days for a significant response to be noted (Garden et al, 2019; Johnson, 2020). Mean platelet cell volume (MPCV) readings can be more reliable than haematocrit as a result of the presence of agglutination (Garden et al, 2019; Johnson, 2020). Immune-mediated haemolytic anaemia can be deemed diagnostic, supportive or suspicious according to current guidelines (Woodward and White, 2020) as there are no standardised tests available, and test specificity or sensitivity can depend on the type of test and the performance of the user (MacNeill et al, 2019). Treatment of immune-mediated haemolytic anaemia is through immune suppression by glucocorticoid use; a number of additional medications can supplement this primary therapy in order to reduce glucocorticoid dose and associated adverse effects (Swann et al, 2019). Intravenous fluid therapy is recommended to eliminate any dehydration deficits, reduce risk of thromboembolism, reduce intravascular haemolysis and increase renal perfusion. While this treatment will potentially lower the platelet cell volume, it also allows the dilution of bilirubin levels and maintenance of healthy tissue perfusion (Palin, 2021). If medical management fails, removal of the spleen can eliminate a contributing factor in red blood cell destruction, and can increase survival rates as well as decrease recovery times, but risk must be considered to the long-term health of the patient as well as surgical suitability (Balch and Mackin, 2007).

Patient presentation

The patient, Patch, an 8-year-old male neutered Jack Russell Terrier weighing 8.8 kg, presented with a history of lethargy and sudden onset of inappetence. Clinical symptoms alongside a packed cell volume of 19%, RBC 0.25x10¹²/L, haemoglobin 63 g/L, high platelets and borderline basophils (Table 1) was deemed by the veterinary surgeon to be an open diagnosis, with the most likely differentials being hemangiosarcoma or immune-mediated haemolytic anaemia. At this time it was unfortunately not possible to gain a sufficient sample to test for antinuclear antibody (ANA) and Coombs tests, due to the patient's poor blood pressure.

Table 1.

Blood results

Treatment initiated

Treatment for Patch was initiated with dexafort steroid injection (0.5 ml) on 8 April. The standard recommendations are to treat immune-mediated haemolytic anaemia with prednisolone, prednisone or dexamethasone if the patient is inappetant, as in this instance. There has been no significant clinical differences between the available steroid medications, although excessive doses are to be avoided to reduce adverse effects (Swann et al, 2019). Dexamethasone was chosen for its heightened anti-inflammatory potency (Balch and Mackin, 2007).

In this case, hospitalisation for the close monitoring of the patient was refused by the client on the basis of the significant level of stress and aggression exhibited by the patient in the clinic; it was decided overall this would likely impede his recovery (Palin, 2021), although this was normal behaviour for this patient.

By 13 April, the patient's packed cell volume had reduced further to 14%, with slight improvement in RBC to 0.38, haemoglobin further reduced to 38, high WBC 27.66, high neutrophils 22.28 and marginally high monocytes 2.32 with visible bloating. Steroid treatment dose was increased (0.7 ml dexafort) and a second steroid was added with the use of dexadreson (0.5 ml).

By 17 April the patient was showing signs of significant improvement with MPCV 28%, RBC 4.09, haemoglobin 113, WBC 18.68 and neutrophils 15.88. Additionally noted were low creatinine 40 µmol/L, elevated alanine transaminase 768 U/L, elevated alkaline phosphatase 1684 U/L and low amylase 377 U/L.

At this stage, sufficient blood sampling could be taken for anti-nuclear antibody (ANA) and Coombs tests which were sent to an external laboratory.

Antibody testing

Coombs direct antiglobulin test (DAT) is recommended for confirmation of immune-mediated haemolytic anaemia but it is not completely specific or sensitive, whereas saline macro-agglutination has 100% specificity, and this agglutination may affect the accuracy of the direct antiglobulin test (Cornell University, 2016; Garden et al, 2019).

The direct antiglobulin test detects erythrocyte-bound auto- and alloantibodies and is considered accurate in 97–99% of cases (Theis and Hashmi, 2022; Idalan et al, 2023). This is deemed more reliable than indirect antibody testing detecting free antibodies in serum or plasma, although the latter may aid diagnosis when fresh blood sampling is not possible (Idalan et al, 2023). A direct antiglobulin test can be a quantitative enzyme-linked immunosorbent assay (ELISA), flow cytometry (Garden et al, 2019), or other immunoassay techniques. This may be necessary if false negatives are suspected, as many tests rely on IgG or complement C3 and not IgM or IgA, or where antibody levels may be below the level detected in the non-quantitative test (Rodberg, 2022; Theis and Hashmi, 2022). A Coombs test may be unnecessary in cases where macro- and microagglutination is visibly present. In this case it was deemed suitable for confirmation and removal of any artefact (Johnson, 2020).

In Patch's case, the test was taken after glucocorticoid therapy had been instigated, as a result of inability to achieve an appropriate sample size before treatment, which may have affected the results (Swann et al, 2019), this is against the current treatment rationale, but was unavoidable because of the blood sample sizes obtained and the patient's severely debilitated state.

Referral for imaging

As the local clinic is located on an island, with no veterinary surgeon assessed ultrasonography capacity at the time of presentation, travel to the closest clinic with these facilities was arranged once the patient was stable enough for transport. Because of the concern of stress, air transport was deemed unsuitable and sea transport was arranged on 19 April. At this clinic, radiography showed an unconfirmed mass in the abdomen, and ultrasound showed an abnormal liver lobe appearance; this was not definitive and the owner opted against investigative surgery at the time. Repeat scans were scheduled for 2 months to monitor for changes and again discuss investigative surgery.

As the patient progressed and his bloating had resolved, on 25 April he was moved to oral steroids; dexamethasone 4 mg once daily. This dose reduction following significant improvement has been recommended to reduce the systemic effect of the steroid treatment (Swann et al, 2019).

MPCV was monitored and remained stable at 42% on 4 May and 37% on 18 May. Once PCV has been maintained over 30% and the patient remains stable, the recommendations for immune-mediated haemolytic anaemia patients are to reduce steroids by 25%, followed by a further 25% every 2–3 weeks, with PCV analysis before each dose change. An expected treatment duration is 3–6 months for glucocorticoids (Balch and Mackin, 2007; Swann et al, 2019). In this case the dose reduction was less gradual, due to the rate of his recovery and the level of side effects including polyuria or polydipsia, and he was reduced after 10 days to 3 mg once daily. After another 10 days this was reduced again to 2 mg once daily.

On 10 May, the anti-nuclear antibody/Coombs test came back as negative. This was considered in line with his clinical recovery and understood to be likely a false negative, unless haemangiosarcoma could be confirmed with future imaging or investigative surgery.

By 30 May the RBC was borderline normal at 4.98x10¹²/L, as was alkaline phosphatase <10 U/L.

By 22 June, all bloods were within normal limits, MPCV 43% and the oral steroid dose had been tapered to such a degree it could be discontinued, as once the dose is below 0.25–0.5 mg/kg, steroids can be discontinued, although this was achieved by a more rapid dose reduction than the recommended 2–4 months (Balch and Mackin, 2007).

Relapse

On 6 September, the patient presented with inappetence, acutely pale mucous membranes and rostral pinna, high temperature, macro-agglutination on blood sampling, extreme lethargy and slight abdominal bloating. Figure 2 shows relapse protocol guidelines for immune-mediated haemolytic anaemia. Bloods showed a manual MPCV 17%, low RBC 0.38x10¹²/L, low haemoglobin 38 g/L, marginally low platelets 143 x10⁹/L, and marginally high bilirubin 20 µmol/L. After assessment and discussion with the owner and the veterinary surgeon off-island, treatment as in the previous episode with dexafort steroid (0.5 ml) was agreed, with added antibiotics due to the immunocompromised status of the patient undergoing long-term steroid therapy, with a plan to review in 4 days. Discussion between the veterinary surgeon and client was open and detailed, explaining the poor prognosis for relapse with the current presenting symptoms more severe than the primary presenting episode. Once again hospitalisation was offered and at this stage declined. Immune-mediated haemolytic anaemia relapse episode guidelines recommend the diagnosis be re-confirmed to rule out possible triggers, before steroid treatment was commenced (Swann et al, 2019). However, because of Patch's symptoms and the inability to repeat imaging without travel, as well as the difficulty in gaining a suitable volume of blood sample, this was not performed.

On 9 September, the patient presented due to a further decline in condition including bloated abdomen and non-ambulatory collapse. Bloods showed a further decline in MPCV to 12%, with low RBC 0.43 x10¹²/L, low haemoglobin 33 g/L, improved within normal limits platelets, high reticulocytes 129.6 K/µL, high white blood cells 41.7 K/µL, high neutrophils 34.59 x10⁹/L, high monocytes 4.75x10⁹/L, high basophils 0.26x10⁹/L, high urea 16.6 mmol/L, high alanine transaminase 731 U/L, marginally high alkaline phosphatase 264 U/L, high bilirubin 111 µmol/L, questionably high amylase <2500 U/L and lipase 5853 U/L with active jaundice present on blood sample, at mucous membranes and on skin tissues. Discussion with the veterinary surgeon and owner at this stage with declining prognosis gave restricted options, but priority was given to preventing imminent tissue hypoxia (Balch and Mackin, 2007). These options included an emergency blood transfusion, to increase steroid dose and combine with intravenous fluid therapy, or travel to a clinic with imaging for repeat liver scan and advanced medical management including vincristine. Since the patient was not in a stable condition for sea travel, there were major concerns with these options, and the owner was warned all options held a very guarded prognosis. The owner opted to trial steroid increase, IVFT fluids and blood transfusion. Due to the poor prognosis of the case they understood the risks involved, as no blood typing tests were present at the clinic for the donor or the recipient, and his blood type was not known, although he had no prior history of transfusions.

Blood transfusion

Transfusions are indicated for a number of reasons, often as a life-saving adjunct to other medical treatment (Aleksandra and Justyna, 2021; Sai et al, 2023). Ideal donor dogs are healthy and dog erythrocyte antigen 1.1, 1.2 and 7 negative, as these are considered universal donors (Aravindh and Jacob, 2021; Sai et al, 2023), although other blood groups are more prevalent in other parts of the world (Mangiaterra et al, 2021). Cross matching should be completed prior to a transfusion where possible, although some inconsistencies have been found in certain tests (Zaremba et al, 2022). While cross matching should prevent antibody presence to red blood cell, white blood cell and platelets, antibodies may still cause an immediate haemolytic reaction (Sai et al, 2023).

Recommendations for immune-mediated haemolytic anaemia cases are to give fresh packed red blood cells; however, as this was unavailable, whole blood was chosen as a reasonable and accessible alternative (Swann et al, 2019; Callan, 2022).

Intravenous fluid therapy and steroids were provided immediately at admission while a donor dog was located. The donor patient was a male neutered 6-year-old Labrador, who was fit and healthy, over 25 kg, on no regular medications, with vaccinations up to date and had not travelled abroad, so an ideal candidate (Sai et al, 2023). Considering the resources of the clinic and nature of the donor, the sample was to be taken from the cephalic vein, which is suitable when a smaller donation is being taken (Sai et al, 2023). The donation was to be combined with 2 ml citrate phosphate dextrose adenine (CDPA) per 8 ml donated blood as per the veterinary surgeon instruction.

The calculated volume to be given was determined by using the Pet Blood Bank calculator for increasing PCV by 10%. This resulted in a required volume of 120–200 ml (Pet Blood Bank UK, 2023). A full calculation can be followed using the formula: Volume = 90 x weight x (change in PCV/donor PCV) (Balch and Mackin, 2007). The total donation supplied was restricted because of the volume of CDPA in stock and resulted in 35 ml anticoagulant combined with 112ml donor blood taken using an aseptic technique for a total infusion volume of 140 ml. Blood treated with this anticoagulant can be stored at 4°C for 4 weeks (Sai et al, 2023). This was given via a blood transfusion giving set with filter commenced within 2 hours of donation receipt, after first resuspending the blood by gentle inversion of the bag. The rate of blood transfusion was 0.5 ml/kg/h or 1 drop/40 seconds for 30 mins followed by 5 ml/kg/h or 1 drop/4 seconds for a total transfusion time of 2 hours (Pet Blood Bank UK, 2023). The catheter placed was a 21G 5 ⁄ 8 inch because of the size of the patient. It was accepted that there would be some degree of haemolysis (Perez and Darrow, 2023).

Reactions to blood transfusions may be acute or delayed and include anaphylaxis, circulatory overload, thromboembolism, fever, sepsis and infectious diseases.

The symptoms of these may include pyrexia, tachypnoea, tachycardia, bradycardia, coughing, dyspnoea vocalisation, arrhythmias, hypotension, muscle tremors or convulsions, anorexia, vomiting, diarrhoea, erythema, pruritus, urticarial lesions, oedema, jaundice, cardiopulmonary arrest and a significant drop in MPCV more than could be attributed to any fluid therapy (Palin, 2021; Sai et al, 2023).

No reactions were noted during or after the transfusion for this patient, and his heart rate, respiration rate, temperature, mucous membrane colour and mentation were monitored every 5 minutes during the first 30 minutes of transfusion time, then every 15 minutes for the remainder of the 2 hours transfusion time (Aravindh and Jacob, 2021; Sai et al, 2023).

After the blood transfusion, the patient's IV catheter was flushed using sterile saline, and intravenous fluid therapy was restarted at 1.5x maintenance and monitored hourly for both improvement and delayed transfusion reaction. Within the first 6 hours the patient's jaundice skin was beginning to improve, and by 12 hours post-transfusion on 10 September, a slight improvement in mucous membrane pink colouration had been achieved. Little change in demeanour or energy levels were noted at this time, although the patient began eating after maropitant injection and a visit from the owner. The patient had a slightly unsteady gait but was able to stand himself, although not for pro-longed periods (over 30 seconds). By 24 hours post-infu-sion, the patient's appetite was much improved without further maropitant and his gait was steady, with an ability to urinate without collapse. At this time his mucous membranes were significantly more pink, with minor jaundice present. A small blood sample was taken for manual PCV and found an increase to 18%.

Recovery

On 11 September, Patch was enthusiastically appetant, ambulatory voluntarily and requiring no assistance for eliminations, and his mucous membranes showed continued improvement. Bloods showed a further improvement with almost all parameters including MPCV %, red blood cells 1.03x10¹²/L, haemoglobin 1.03g/L, platelets 143x10⁹/L, white blood cells 32.79 K/µL, neutrophils 34.27x10⁹/L, monocytes 2.96x10⁹/L, basophils 0.25x10⁹/L, urea within normal levels, alanine transferase 558 U/L. However, Patch had high reticulocytes 255.7 K/µL and high alkaline phosphatase 499 U/L. At this time it was agreed the patient could be discharged to continue with oral antibiotics and repeat the steroid injection in 48 hours, as well as taking bloods for MPCV regularly depending on his condition. This decision was made due to the return of his aggressive behaviour in the clinic as his condition improved, which made it increasingly challenging to interact and appropriately care for him safely.

By the next day Patch was active and lively. On the 13 September, he had a repeat of the steroid dexafort injection (0.7 ml), with a plan to take his MPCV at the next steroid injection if there were no concerns before then, and to swap to oral steroids once stable.

On 18 September, the steroid dexafort injection (0.7 ml) was repeated and the manual MPCV was 28%. The owner reported he was doing very well, mucous membranes were pink with no jaundice or abdominal bloating present. At this stage the patient had returned to their usual demeanour, which unfortunately included reactivity to clinic staff, handling techniques and blood sampling. The registered veterinary nurse, veterinary surgeon and owner discussed the requirement for regular blood sampling in order to monitor MPCV alongside other parameters as steroid doses are reduced, with consideration for the anxiety this caused Patch. It was agreed steroid reduction would be significantly slower than during his previous recovery, so blood sampling could be taken regularly to monitor for early signs of relapse. This follows the guidance for immune-mediated haemolytic anaemia relapse cases, which advises that the steroid dose reduction should be tapered slower than in the primary occurrence, and bloods should be taken prior to each dose reduction (Swann et al, 2019).

At this time blood typing was discussed for Patch in case a future blood donation was required, although this needed to be delayed until 90 days after his received transfusion. Patch continued to be clinically bright, active and healthy. On 23 September he was moved to oral dexamethasone tablets at 3 mg once daily for 14 days, to be reduced to 2 mg once daily for a further 14 days, then 1 mg once daily, at which point he could be trialled on prednisolone, with repeat MPCV bloods as discussed before each dose reduction.

Sea travel for the patient to have ultrasound imaging was not possible after this time because of seasonal restrictions. As the differential during treatment so far was supportive of immune-mediated haemolytic anaemia, after this recent relapse it was decided this imaging should be delayed until spring. Air transport would have been potentially possible, but the owner was concerned at the level of distress this would cause Patch and preferred to avoid it.

Bloods for haematology were taken on 3 October and all values had continued to improve. Unfortunately, the client had been dosing incorrectly, so treatment was restarted at the originally agreed dose of 2 mg dexamethasone twice a day for 14 days, then 3 mg once a day for 14 days, then 2 mg once a day for 14 days, with a plan to retake bloods (providing Patch remained stable until then) then reduce again to 1 mg once daily for at least 14 days before a swap to prednisolone, if continued improvement was seen. At any point, if deterioration was seen in his condition, the owners were under instruction to bring him to the clinic as an emergency. More frequent blood sampling was not to be completed as originally planned because of client concern over the stress and anxiety the procedure caused the patient, and the veterinary team acknowledged the negative impact stress has on morbidity and mortality, as well as impacts on clinical parameters (Palin, 2021).

On 31 October, Patch was seen in the clinic for routine bloods with no current concerns, and the client had just reduced the dose to 1 mg once daily. On presentation, he had evident bloating and pale mucous membranes with poor blood pressure, although he was difficult to handle and sample as per his usual aggressive behaviours. His bloods exceeded expectations considering his presentation, with a MPCV of 34%, but considering his clinical symptoms, an increase to 3 mg once daily was agreed, with a slower reduction planned including no decrease in dosing until he had stabilised for at least 3 weeks. Once again the veterinary surgeon and client discussed the long-term implications of steroid use, and due to the inability of further investigations such as ultrasound imaging, the treatment was to be continued as planned. The case continues to be monitored regularly in practice.

Other medical managements

Secondary drugs such as azathioprine, cyclosporine or mycophenolate mofetil can be used to allow increased tapering of glucocorticoids and assist in the treatment, although the confidence in their effectivity is low and the use of a third medication should be avoided (Swann et al, 2019); however, there is some evidence they may help to prevent future relapses (Weng et al, 2023). Antithrombotic treatment is recommended in cases of intravascular hemolysis, autoagglutination, marked leukocytosis and increased liver enzyme activities unless severe thrombocytopenia is present (Swann et al, 2019).

Conclusions

This case allowed the empowerment of the registered veterinary nurses in the clinic to provide consistent and detailed care for a complex case of an aggressive patient including a blood transfusion and close monitoring of presenting symptoms and changes in demeanour and clinical parameters.

As a result of the island location of the local community and clinic, with a small population of residents and patients, this case instigated a registered veterinary nurse discussion over the accessibility of blood products and the safety of administration protocols. The clinic is a charity, and, before this case, there had not been a case of blood transfusion in over 14 years, so the routine stocking of blood products would be financially inappropriate as they would likely expire before use. Orders of emergency supplies to the island can take over 48 hours to arrive and are weather dependent, which is not appropriate when an emergency presents. As a viable alternative, a campaign has been initiated to blood type all resident canine patients, so that in the case of future transfusion requirement, clients will already know which type of blood their pet needs to receive, and the clinic will have a potential database of pets suitable for donating compatible blood. This campaign has been very well received locally and typing is currently underway, with consideration to potentially type feline patients in the near future in a similar initiative.

KEY POINTS

• Cases with closely linked differentials can be difficult to manage, and both diagnostic testing and owner understanding of prognosis should be thoroughly explained from the start, as well as the risks and likelihood of relapses.
• Regular monitoring of changes in parameters, as well as demeanour, are vitally important in these cases.
• Medical management of these cases can be difficult; however, nursing management and care has a vital role, particularly in the regular and open communication with the owner.
• Blood transfusions, once requested by the veterinary surgeon, can be life saving, and registered veterinary nurse confidence in assisting or performing of these in clinics cannot be underestimated, even in clinics which see low incidences of emergency or critical cases.
• Blood typing should be encouraged where possible in healthy patients; this case has enabled the clinic to pre-emptively blood type a large volume of the population in case future transfusions are required, particularly in an isolated island location and charity clinic where supplies for typing and stocking blood products is limited.