Changes

In cases of pure red cell aplasia, a Coomb's test may still be positive but, experimentally, a definitive diagnosis can only be made by transfusing the serum of one animal to another and documenting the development of anaemia in the recipient.

In cases of pure red cell aplasia, a Coomb's test may still be positive but, experimentally, a definitive diagnosis can only be made by transfusing the serum of one animal to another and documenting the development of anaemia in the recipient.

===Diagnostic Imaging===

===Diagnostic Imaging===

Imaging may be indicated to rule out other potential causes of the signs observed but it is not always necessary to make a diagnosis of IMHA.  Hepatosplenomegaly will be the major findings on both radiographs and ultrasound scans.

Imaging may be indicated to rule out other potential causes of the signs observed but it is not necessary to make a diagnosis of IMHA.  Hepatosplenomegaly will be the major findings on both radiographs and ultrasound scans.

==Treatment==

==Treatment==

===Stabilisation===

===Stabilisation===

In animals that have lost a large percentage of their PCV acutely, it is likely that a blood transfusion will be required.  Since animals with IMHA are not usually hypovolaemic, packed red blood cells are often transfused to replace erythrocytes without significantly expanding the plasma volume.  In emergency situations, whole blood or synthetic haemoglobin molcules (such as Oxyglobin [tm]) may be used to support the oxygen carrying capacity of the patient.  Oxygen may be provided to tachypnoeic and dyspnoeic patients by facemask, nasal catheter or flow-by.  

In animals that have lost a large percentage of their [[Packed Cell Volume|PCV]] acutely, it is likely that a [[Blood Transfusion|blood transfusion]] will be required.  Since animals with IMHA are not usually hypovolaemic, packed red blood cells are often transfused to replace erythrocytes without significantly expanding the plasma volume.  In emergency situations, whole blood or synthetic haemoglobin molcules (such as Oxyglobin [tm]) may be used to support the oxygen carrying capacity of the patient.  Oxygen may be provided to tachypnoeic and dyspnoeic patients by facemask, nasal catheter or flow-by.  

===Immunosuppressive Therapy===

===Immunosuppressive Therapy===

Whatever supportive measures are taken, the autoimmune response must be controlled to prevent the continuing lysis of red blood cells.  The following types of drug are typically used to achieve this goal:

Whatever supportive measures are taken, the autoimmune response must be controlled to prevent the continuing lysis of red blood cells.  The following types of drug are typically used to achieve this goal:

*'''Corticosteroids''' such as prednisolone and dexamethasone are used universally as a first-line treatment for IMHA as they are frequently effective and they are available in a variety of preparations.  Traditionally, very high doses of corticosteroids have been used to try to control the autoimmune response and dose rates beyond 2-3 mg/kg may be associated with significant adverse effects.  More recently, there has been a move to add further immunosuppressive agents (see below) in a polypharmaceutical approach which allows the clinician to keep the corticosteroid dose rate at a reasonable level.

*'''Corticosteroids''' such as prednisolone and dexamethasone are used universally as a first-line treatment for IMHA as they are frequently effective, act rapidly and are available in a variety of preparations.  Traditionally, very high doses of corticosteroids have been used to try to control the autoimmune response but dose rates beyond 2-3 mg/kg may be associated with significant adverse effects.  More recently, there has been a move to add further immunosuppressive agents (see below) in a polypharmaceutical approach which allows the clinician to keep the corticosteroid dose rate at a reasonable level.  Corticosteroids act to control both the cell- and antibody-mediated immune responses.

*'''Azathioprine''' is frequently used in the management of IMHA and it has effects on both cell- and antibody-mediated immune responses.  It may take 3-4 weeks of treatment before patient experiences the maximal effects of the drug.  Azathioprine is a cytotoxic drug and gloves should be worn to administer tablets.  Owners or keepers should be made aware that the active drug or its metabolites may be present in the saliva and other secretions of animals receiving the drug.

*'''Azathioprine''' is frequently used in the management of IMHA and it has effects on both cell- and antibody-mediated immune responses.  It may take 3-4 weeks of treatment before the patient experiences the maximal effects of the drug.  Azathioprine is a cytotoxic drug and gloves should be worn to administer tablets.  Owners or keepers should be made aware that the active drug or its metabolites may be present in the saliva and other secretions of animals receiving the drug.

*'''Ciclosporin A''' is a fungal metabolite that inhibits a signaling molecule (ciclophilin) involved in T cell activation.  Since B cells require T cell help to become activated, differentiate into plasma cells and produce antibodies, there is a rationale for the use of ciclosporin in cases of IMHA.   

*'''Ciclosporin A''' is a fungal metabolite that inhibits a signaling molecule (ciclophilin) involved in T cell activation.  Since B cells require T cell help to become activated, differentiate into plasma cells and produce antibodies, there is a rationale for the use of ciclosporin in cases of IMHA but there are currently no reports of its relative efficacy compared to the other immunosuppressive drugs.   

*Other less commonly-used drugs include danazol, mycophenolate mofetil and cyclophosphamide.

*Other less commonly-used drugs include danazol (a steroid related to testosterone), mycophenolate mofetil and cyclophosphamide. Cyclophosphamide was used widely in the management of IMHA but two separate studies have shown that its use is associated with higher rates of mortality.

 

===Adjunctive Therapy===

===Adjunctive Therapy===

Animals with IMHA frequently suffer concurrent vomiting, regurgitation and diarrhoea while hospitalised.  These conditions are frequently managed with [[Gastroprotective Drugs|gastro-protectant drugs]] such as sucralfate, ranitidine and omeprazole to prevent the development of gastro-duodenal ulceration and [[Oesophagitis|oesophagitis]].

Animals with IMHA frequently suffer from concurrent vomiting, regurgitation and diarrhoea while hospitalised.  These conditions are frequently managed with [[Gastroprotective Drugs|gastro-protectant drugs]] such as sucralfate, ranitidine and omeprazole to prevent the development of gastro-duodenal ulceration and [[Oesophagitis|oesophagitis]].

Antibiotics are frequently administered to animals which present with acute haemolytic crises but these should be used judiciously on a case-by-case basis.

Antibiotics are frequently administered to animals which present with acute haemolytic crises but these should be used judiciously on a case-by-case basis.

==Prognosis==

==Prognosis==