Paroxysmal nocturnal hemoglobinuria (PNH) is a rare, acquired, life-threatening disease of the blood characterized by destruction of red blood cells by the complement system, a part of the bodys innate immune system. This destructive process occurs due to deficiency of the red blood cell surface protein DAF, which normally inhibits such immune reactions. Since the complement cascade attacks the red blood cells within the blood vessels of the circulatory system, the red blood cell destruction (hemolysis) is considered an intravascular hemolytic anemia. Other key features of the disease, such as the high incidence of venous blood clot formation, are incompletely understood.PNH is the only hemolytic anemia caused by an acquired (rather than inherited) intrinsic defect in the cell membrane (deficiency of glycophosphatidylinositol or GPI) leading to the absence of protective exterior surface proteins that normally attach via a GPI anchor. It may develop on its own ("primary PNH") or in the context of other bone marrow disorders such as aplastic anemia ("secondary PNH"). Only a minority of affected people  have the telltale red urine in the morning that originally gave the condition its name.Allogeneic bone marrow transplantation is the only cure, but has significant rates of additional medical problems and death. The monoclonal antibody eculizumab reduces the need for blood transfusions and improves quality of life for those affected by PNH. Eculizumab dramatically alters the natural course of PNH, reducing symptoms and disease complications as well as improving survival to the extent that it may be equivalent to that of the general population.
Animals affected by laryngeal paralysis have reduced tolerance for exercise and heat and an increased risk of aspiration pneumonia. The condition is not generally regarded as causing pain, other than physical distress and anxiety caused by any difficulty in breathing or emotional distress from any difficulty with physical movement. Where laryngeal paralysis is related to a general progressive polyneuropathy, as in GOLPP, the nervous system will gradually degenerate causing increasing difficulty in management of the limbs (especially rear limbs), swallowing and breathing, and eventually in most cases euthanasia. Laryngeal paralysis is fairly common in large breed and geriatric dogs, particularly in the Labrador retriever, is rarely found in cats, and can also occur in horses where it is referred to as roaring, roarers syndrome, or medically as laryngeal hemiplegia or  recurrent laryngeal neuropathy (RLN). Laryngeal paralysis can be unilateral or bilateral depending upon dysfunction of one or both arytenoid cartilages. Causes
In most cases, the cause of laryngeal paralysis is unknown or idiopathic. However, the disorder may arise secondary to general neuropathies, generalized neuromuscular diseases, muscular diseases, neoplasia either in the cervical (neck) region or the cranial mediastinum, or trauma. This acquired form occurs predominantly in middle-aged to old large breed or giant breed dogs such as the Labrador Retriever, golden retriever, Siberian Husky, Newfoundland, and St. Bernard. Usually these dogs are born with a normal larynx, but over time the nerves and muscles that control the laryngeal cartilages lose function.Laryngeal paralysis may also be congenital in some breeds (e.g.