Circulatory Diseases

Anemia

      1.     Regenerative Anemias

    1. A.     Blood Loss Anemia

Acute blood loss can lead to shock and even death if >30-40% of blood is lost and the hypovolemia that develops is not treated aggressively with IV fluids or compatible blood, or both. For more information click here or call your veterinarian.

    1. B.      Hemolytic Anemia 

      1. a.      Alloimmune Hemolysis

Neonatal isoerythrolysis (NI) is an immune-mediated hemolytic disease seen in newborn horses, mules, cattle, pigs, cats, and, rarely, in dogs. NI is caused by ingestion of maternal colostrum containing antibodies to one of the neonate’s blood group antigens. For more information click here or call your veterinarian.

      1. b.      Heritable Diseases

Several heritable RBC disorders cause anemia. Pyruvate kinase (PK) deficiencies are seen in Basenjis, Beagles, West Highland White Terriers, Cairn Terriers, and other breeds, as well as Abyssinian and Somali cats. For more information click here or call your veterinarian.

      1. c.      Immune-mediated Hemolytic Anemia

Immune-mediated hemolytic anemia (IMHA) can be primary or secondary to neoplasia, infection, drugs, or vaccinations. In IMHA, the body no longer recognizes RBC as self and develops antibodies to circulating RBC, leading to RBC destruction by macrophages and complement. For more information click here or call your veterinarian.

      1. d.      Infections

Many infectious agents—bacterial, viral, rickettsial, and protozoal—can cause anemia, by direct damage to RBC, leading to hemolysis, or by direct effects on precursors in the bone marrow. For more information click here or call your veterinarian.

      1. e.      Microangiopathic Hemolysis

Microangiopathic hemolysis is caused by RBC damage secondary to turbulent flow through abnormal vessels. For more information click here or call your veterinarian.

      1. f.       Toxins

Toxins and drugs can cause anemia by many mechanisms. Those implicated most frequently in animals and their pathogenic mechanisms are listed in Table:Toxic Causes of Anemia. For more information click here or call your veterinarian.

      2.     Nonregenerative Anemias

  1. A.     Anemia of Chronic Disease

Anemia of chronic disease can be characterized as mild to moderate, nonregenerative, normochromic, and normocytic. It is the most common form of anemia seen in animals. For more information click here or call your veterinarian.

  1. B.      Nutritional Deficiencies

Nutritional deficiency anemias develop when micronutrients needed for RBC formation are not present in adequate amounts. Anemia develops gradually and may initially be regenerative, but ultimately becomes nonregenerative. For more information click here or call your veterinarian.

  1. C.     Primary Bone Marrow Diseases

Primary bone marrow disease or failure from any cause can lead to nonregenerative anemia and pancytopenia. With diffuse marrow involvement, granulocytes are affected first, followed by platelets and finally RBC. For more information click here or call your veterinarian. 

  1. D.     Renal Disease 

Chronic renal disease is a common cause of nonregenerative anemia in animals. For more information click here or call your veterinarian.

II.       Blood Parasites

      1.     Babesiosis

Babesiosis is caused by intraerythrocytic protozoan parasites of the genus Babesia. The disease, which is transmitted by ticks, affects a wide range of domestic and wild animals and occasionally humans. For more information click here or call your veterinarian.

      2.     Eperythrozoonosis

A hemolytic, sometimes febrile, disease is caused by rickettsiae of the genus Eperythrozoon of the family Rickettsiaceae. Each Eperythrozoon spp is host specific. Dogs can be infected with E canis. For more information click here or call your veterinarian.

      3.     Hemobartonellosis (Feline infectious anemia)

Feline infectious anemia (FIA) is an acute or chronic disease of domestic cats, seen in many parts of the world, caused by a rickettsial agent that multiplies within the vascular system. For more information click here or call your veterinarian.

      4.     Hepatozoonosis and American Canine Hepatozoonosis

Hepatozoonosis is a tickborne disease of wild and domestic carnivores caused by the protozoal agent, Hepatozoon canis. For more information click here or call your veterinarian.

      5.     Trypanosomiasis

  1. A.     Chagas’ Disease (Trypanosoma cruzi infection)

The trypanosome is pathogenic to humans and occasionally to young dogs and cats. T cruzi should be suspected in endemic areas in dogs that die acutely or have myocarditis. For more information click here or call your veterinarian.

  1. B.      Tsetse-transmitted Trypanosomiasis

This group of diseases caused by protozoa of the genus Trypanosoma affects all domestic animals. In dogs and cats, T brucei is probably the most important. The primary clinical signs are intermittent fever, anemia, and weight loss. For more information click here or call your veterinarian.

  1. C.     Surra (Trypanosoma evansi infection)

Surra is separated from the tsetse-transmitted diseases because other biting flies that are found within and outside tsetse fly areas usually transmit it. The disease can be fatal, particularly in dogs. For more information click here or call your veterinarian.

III.       Canine Malignant Lymphoma

Canine malignant lymphoma is a progressive, fatal disease caused by the malignant clonal expansion of lymphoid cells. For more information click here or call your veterinarian.

IV.       Hemostatic Disorders

      1.     Bleeding Diatheses

    A.     Coagulation Protein Disorders
  1. a.      Congenital Coagulation Protein Disorders 

In a severe deficiency or functional defect of coagulation proteins, clinical signs appear at an early age. Marked reductions in activity of coagulation proteins essential to hemostasis are usually fatal. For more information click here or call your veterinarian.

  1. b.      Acquired Coagulation Protein Disorders

Most coagulation proteins are produced primarily in the liver. Therefore, liver disease characterized by necrosis, inflammation, neoplasia, or cirrhosis often is associated with decreased production of coagulation proteins. For more information click here or call your veterinarian.

  1. B.      Platelet Disorders

 

  1. a.      Congenital Thrombocytopenia 
      1.                                                               i.      Fetal and neonatal alloimmune thrombocytopenia occur when maternal antibodies are produced against a paternal antigen on fetal platelets. For more information click here or call your veterinarian.
      2.                                                              ii.      Cyclic hematopoiesis in gray Collie dogs (Inherited Leukocytic Disorders) is characterized by 12-day cycles of cytopenia. For more information click here or call your veterinarian.
  1. b.      Acquired Thrombocytopenia 

Acquired thrombocytopenias are reported frequently in dogs and cats. Numerous causes have been identified, most involving immunologic or direct destruction of platelets. For more information click here or call your veterinarian.

  1. c.      Congenital Platelet Function Disorders 

Congenital disorders of platelet function affect platelet adhesion, aggregation, or secretion. They can be either intrinsic or extrinsic to platelets. For more information click here or call your veterinarian.

  1. d.      Acquired Platelet Function Disorders 

Dogs with immune-mediated thrombocytopenia also may have an acquired platelet functional defect. Dogs can have excessive bleeding tendencies without severely decreased platelet concentrations. For more information click here or call your veterinarian.

  1. C.     Vascular Disorders

 

  1. a.      Congenital Vascular Disorders

Cutaneous asthenia (Ehlers-Danlos syndrome, rubber puppy disease) is caused by a defect in the maturation of type I collagen. For more information click here or call your veterinarian.

  1. b.      Acquired Vascular Disorders
  1.                                                              i.       Rocky Mountain spotted fever is caused by Rickettsia rickettsii , which is transmitted by the ticks. The rickettsial organisms invade endothelial cells and cause cellular death with resultant perivascular edema and hemorrhage. For more information click here or call your veterinarian.
  2.                                                             ii.       Canine herpesvirus generally affects puppies 7-21 days old. Generalized necrotizing vasculitis is accompanied by perivascular hemorrhage. For more information click here or call your veterinarian.

 

      2.     Pathologic Thrombosis

  1. A.     Primary or Inherited Anticoagulant Disorders 

Congenital deficiency of any anticoagulant protein has not been recognized in domestic animals. If such a condition exists, it is probably incompatible with life. For more information click here or call your veterinarian.

  1. B.      Secondary or Acquired Anticoagulant Disorders

Certain diseases in animals have been associated with increased risk of thrombosis. For more information click here or call your veterinarian.

V.       Leukocytic Disorders

      1.     Leukocytosis and Leukopenia

Leukocytosis is an increase in the total number of circulating WBC; leukopenia is a decrease. For more information click here or call your veterinarian.

      2.     Leukemia and Lymphoma

Leukemia and lymphoma with a circulating leukemia should be considered as differential diagnoses in leukocytosis. In some instances of lymphoma without leukemia, necrosis within the tumor induces neutrophilia. For more information click here or call your veterinarian.

      3.     Inherited Leukocytic Disorders 

  1. A.     Chédiak-Higashi Syndrome

This syndrome, inherited as an autosomal recessive, is characterized by leukocyte dysfunction secondary to abnormal lysosomes. For more information click here or call your veterinarian.

  1. B.      Cyclic Hematopoiesis in Gray Collie Dogs

This syndrome, also called Gray Collie syndrome and canine cyclic neutropenia, is an inherited, autosomal recessive immunodeficiency characterized by a profound cyclic neutropenia, overwhelming recurrent bacterial infections, bleeding, and coat color dilution. For more information click here or call your veterinarian.

  1. C.     Pelger-Huët Anomaly

This condition of humans, cats, rabbits, and dogs, characterized by failure of granulocytes to lobulate from the band form to the segmented form, appears to be inherited as an autosomal dominant trait. For more information click here or call your veterinarian.

VI.       Polycythemia

Polycythemia is a relative or absolute increase in the number of circulating RBC resulting in an increased PCV, RBC count, and hemoglobin concentration. For more information click here or call your veterinarian.

VII.       Congenital and Inherited Anomalies of the Cardiovascular System

    1.     Anomalies of Derivatives of the Aortic Arches

  1. A.     Patent Ductus Arteriosus 

Persistence or patency of the ductus with an otherwise normal systemic and pulmonary circulatory system results in significant shunting of blood from left to right, ie, systemic to pulmonary. For more information click here or call your veterinarian.

  1. B.      Persistent Right Aortic Arch

In this vascular ring anomaly, the right aortic arch persists, which causes obstruction of the esophagus at the level of the heart base. For more information click here or call your veterinarian.

      2.     Outflow Tract Obstructions

  1. A.     Aortic Stenosis

Left ventricular emptying may be obstructed at 3 locations. The most common form in dogs is subaortic stenosis. For more information click here or call your veterinarian.

  1. B.      Pulmonic Stenosis 

Pulmonic stenosis is common in dogs and infrequent in cats. It results in obstruction to right ventricular outflow due, in most cases, to dysplasia of the pulmonic valve cusps. For more information click here or call your veterinarian.

  1. C.     Coarctation of the Aorta 

This rare condition of dogs and cats involves narrowing of the aorta distal to the subclavian artery, typically in the area of the ductus arteriosus. For more information click here or call your veterinarian.

      3.     Septal Defects

  1. A.     Atrial Septal Defects 

A communication between the atria may be the result of a patent foramen ovale or a true atrial septal defect. In most cases, blood shunts from the left atrium to the right atrium, causing a volume overload of the right-sided chambers. For more information click here or call your veterinarian.

  1. B.      Ventricular Septal Defects 

Ventricular septal defects are most commonly located in the perimembranous portion of the septum, high in the ventricular septum immediately beneath the right and noncoronary aortic valve cusps on the left and just below the cranioseptal tricuspid valve commissure on the right. For more information click here or call your veterinarian.

      4.     Peritoneopericardial Diaphragmatic Hernia (PPDH) 

Peritoneopericardial diaphragmatic hernia is the most common congenital pericardial disease in dogs and cats. he result is herniation of abdominal viscera into the pericardial sac. For more information click here or call your veterinarian.

      5.     Tetralogy of Fallot 

Tetralogy of Fallot is the most common defect that produces cyanosis. It results from a combination of pulmonic stenosis, a typically high and large ventricular septal defect, right ventricular hypertrophy, and varying degrees of dextropositioning of the aorta. For more information click here or call your veterinarian.

      6.     Mitral Valve Dysplasia

Congenital malformation of the mitral valve complex (mitral valve dysplasia) is a common congenital cardiac defect in cats. Canine breeds predisposed are Bull Terriers, German Shepherds, and Great Danes. For more information click here or call your veterinarian.

      7.     Mitral Stenosis 

Mitral valve stenosis is a narrowing of the mitral valve orifice caused by abnormalities of the mitral valve, resulting in obstruction to left ventricular inflow. This congenital abnormality is rare in dogs and cats and can occur together with other congenital defects. For more information click here or call your veterinarian.

      8.     Tricuspid Dysplasia

Congenital malformation of the tricuspid valve complex is seen occasionally in dogs and cats. Tricuspid dysplasia results in tricuspid insufficiency and systolic regurgitation of blood into the right atrium. For more information click here or call your veterinarian.

      9.     Ectopic Heart 

Ectopic heart is a condition in which the heart is located outside the thoracic cavity, usually in the ventral cervical area. For more information click here or call your veterinarian.

      10. Miscellaneous Congenital Cardiac Abnormalities 

 

  1. A.     Anomalous pulmonary venous connection is a congenital abnormality in which varying numbers of pulmonary veins (from one to all) attach to the right atrium or a systemic vein. For more information click here or call your veterinarian.

 

  1. B.      Endocardial cushion defects (atrioventricular [AV] canal defects, persistent AV ostium, AV septal defects) involve abnormalities of endocardial cushion development and can produce septum primum defects, AV valve abnormalities, and ventricular septal defects. For more information click here or call your veterinarian.

 

  1. C.     Cor triatriatum sinister and dexter result from a fibrous membrane dividing the left or right atrium, respectively. Cor triatriatum sinister has been reported in cats and cor triatriatum dexter in dogs. The affected atrium is divided into 2 chambers. For more information click here or call your veterinarian.

 

  1. D.     Dextrocardia, positioning of the heart in the right hemithorax, can occur as a congenital cardiac defect and by itself is typically benign. It can also occur in combination with situs inversus (an abnormal orientation of the organs of the body). For more information click here or call your veterinarian.

 

VIII.       Heart Disease and Heart Failure

    1.     Heart failure

Heart failure is not a specific disease or diagnosis, but a syndrome in which severe systolic and/or diastolic dysfunction results in decompensation of the cardiovascular system. For more information click here or call your veterinarian.

    2.     Specific Diseases

    1. A.     Degenerative Valve Disease (Endocardiosis, Chronic valvular disease, Chronic valvular fibrosis)

This acquired disease is characterized by nodular thickening of the cardiac valve leaflets, most severely at their free margins. The most commonly affected valves are the mitral or tricuspid valve leaflets. For more information click here or call your veterinarian.

    1. B.      Valvular Blood Cysts or Hematomas

These benign valvular lesions are present in up to 75% of calves <3 wk of age. They are most commonly located on the AV valves. For more information click here or call your veterinarian.

    1. C.     Cardiomyopathies

Cardiomyopathy is defined as any disease involving primarily and predominantly the heart muscle. The cardiomyopathies of animals are idiopathic diseases that are not the result of any systemic or primary cardiac disease. For more information click here or call your veterinarian.

    1. D.     Myocarditis 

Myocarditis is a focal or diffuse inflammation of the myocardium with myocyte degeneration or necrosis causing an adjacent inflammatory infiltrate. There are numerous causes, including several viruses and bacteria. For more information click here or call your veterinarian.

    1. E.      Other Causes of Myocardial Failure 

 

      1. a.      Atrial Standstill

A form of cardiomyopathy resulting in destruction of the atrial myocardium (and occasionally affecting the ventricular myocardium) has been reported in dogs, especially English Springer Spaniels. For more information click here or call your veterinarian.

      1. b.      Doxorubicin-induced Myocardial Failure

Doxorubicin is a common chemotherapeutic agent that causes well-recognized cardiotoxicity. For more information click here or call your veterinarian.

      1. c.      Endocardial Fibroelastosis

This disease of unknown etiology is characterized by focal thickening of the left atrial, left ventricular, and mitral valve endocardium. For more information click here or call your veterinarian.

      1. d.      Arrhythmogenic Right Ventricular Cardiomyopathy

This rare cause of myocardial failure in dogs and cats is restricted primarily to the right heart; however, some left ventricular involvement may be noted. For more information click here or call your veterinarian.

      1. e.      Duchenne’s Cardiomyopathy

This inherited, X-linked neuromuscular disorder has been reported in dogs, particularly Golden Retrievers. For more information click here or call your veterinarian.

    3.     Infective Endocarditis

Infection of the endocardium typically involves one of the cardiac valves, although mural endocarditis may occur. It is believed that endothelial damage must be present for infective endocarditis to develop. For more information click here or call your veterinarian.

    4.     Pericardial Disease 

When fluid accumulates in the pericardial sac, the pressure within the sac increases and progressively compresses the chambers of the heart. Because the right ventricular and right atrial diastolic pressures are less than those of the left chambers, the rising intrapericardial pressure first equilibrates with right-sided diastolic pressures, a condition termed cardiac tamponade. For more information click here or call your veterinarian.

    5.     Systemic and Pulmonary Hypertension 

Systemic hypertension is an increase in systemic blood pressure. There are 2 major types of systemic hypertension. Essential hypertension, which is idiopathic (primary) hypertension, is rare in dogs and cats, but common in humans. Pulmonary hypertension is elevation of blood pressure in the pulmonary circulation. Primary pulmonary hypertension is rare in dogs. For more information click here or call your veterinarian.

    IX.       Heartworm Disease (Dirofilariasis)

Heartworm (HW) infection is caused by a filarial organism, Dirofilaria immitis. At least 70 species of mosquitos can serve as intermediate hosts. Patent infections are possible in numerous wild and companion animal species. In companion animals, infection risk is greatest in dogs and cats housed outdoors. Heartworm infection is completely preventable. For more information click here or call your veterinarian.

X.       Thrombosis, Embolism, and Aneurysm

A thrombus is an aggregation of blood factors that may form when the blood flow in the arteries or veins is impeded. It frequently causes vascular obstruction at its site of origin. All or part of a thrombus may break off and be carried through the bloodstream as an embolus that lodges distally at a point of narrowing. An aneurysm is a vascular dilation caused by weakening of the tunica media of blood vessels. The weakness might be primary or caused by degenerative or inflammatory changes progressing from an intimal lesion. For more information click here or call your veterinarian.