Hypertrophic cardiomyopathy (HCM, or HOCM when obstructive) is a condition in which the heart becomes thickened without an obvious cause. The parts of the heart most commonly affected are the interventricular septum and the ventricles. This results in the heart being less able to pump blood effectively and also may cause electrical conduction problems.People who have HCM may have a range of symptoms. People may be asymptomatic, or may have fatigue, leg swelling, and shortness of breath. It may also result in chest pain or fainting. Symptoms may be worse when the person is dehydrated. Complications may include heart failure, an irregular heartbeat, and sudden cardiac death.HCM is most commonly inherited from a persons parents in an autosomal dominant pattern. It is often due to mutations in certain genes involved with making heart muscle proteins. Other inherited causes of left ventricular hypertrophy may include Fabry disease, Friedreichs ataxia, and certain medications such as tacrolimus. Other considerations for causes of enlarged heart are athletes heart and hypertension (high blood pressure). Making the diagnosis of HCM often involves a family history or pedigree, an electrocardiogram, echocardiogram, and stress testing. Genetic testing may also be done. HCM can be distinguished from other inherited causes of cardiomyopathy by its autosomal dominant pattern, whereas Fabry disease is X-linked and Friedreichs Ataxia is inherited in an autosomal recessive pattern.Treatment may depend on symptoms and other risk factors. Medications may include the use of beta blockers or disopyramide.
Acute Mareks disease is an epidemic in a previously uninfected or unvaccinated flock, causing depression, paralysis, and death in a large number of birds (up to 80%). The age of onset is much earlier than the classic form; birds are four to eight weeks old when affected. Infiltration into multiple organs/tissue is observed. Ocular lymphomatosis causes lymphocyte infiltration of the iris (making the iris turn grey), unequal size of the pupils, and blindness. Cutaneous Mareks disease causes round, firm lesions at the feather follicles. Atherosclerosis is induced in experimentally infected chickens. Immunosuppression is impairment of the T-lymphocytes resulting from Mareks disease, preventing a competent immunological response against pathogenic challenge, with the affected birds become more susceptible to disease conditions such as coccidiosis and Escherichia coli infection. Furthermore, without stimulation by cell-mediated immunity, the humoral immunity conferred by the B-cell lines from the Bursa of Fabricius also shuts down, thus resulting in birds that are totally immunocompromised. Diagnosis
Diagnosis of lymphoid tumors in poultry is complicated due to multiple etiological agents capable of causing very similar tumors. It is not uncommon that more than one avian tumor virus can be present in a chicken, thus one must consider both the diagnosis of the disease/tumors (pathological diagnosis) and of the virus (etiological diagnosis).