Hughes–Stovin syndrome (HSS) is a rare autoimmune disorder often described as inflammation in relation to blood vessels, a form of vasculitis. It is not associated with any known cause and is typically characterized by multiple aneurysms in pulmonary arteries and deep vein thromboses. It is named after the two British physicians, John Patterson Hughes and Peter George Ingle Stovin, who first described it in 1959. HSS is presumed to be a rare variant of Behçet's disease, which entails more general problems with the circulatory system. Due to its clinical similarity with Behçet's disease, it has also been referred to as 'Incomplete Behçet's disease.' Most patients are young adult males between the age of 20–40. Common clinical presentations include fever, cough, dyspnea and hemoptysis. Radiological features are similar to those of Behçet's disease.
Signs and symptoms The signs and symptoms of the disease are mostly associated by the diagnostic feature of the disease, the presence of both pulmonary artery aneurysms and deep vein thromboses. Other symptoms to this disease are typically secondary to these two conditions, the common reported clinical symptoms present in patients are listed below;
Multiple pulmonary aneurysms: secondary to the aneurysms present in the lung, other symptoms may persist, such as; cough, dyspnea (shortness of breath), chest pain and hemoptysis. Peripheral venous thrombosis Recurrent fever Chills intracranial hypertension: this is in relation with the vein thrombosis persistent with patients with HSS, due to blood constriction. pulmonary hypertension: this symptom is associated with the pulmonary aneurysms constricting lung capacity.
Cause The pathogenesis of this syndrome is still not clear and not complete, as there have not been enough studies on it, and therefore not enough published literature. It has been presumed that the possible causes of this syndrome include presence of infections and/or possibly angiodysplasia, characterized by vascular malformation of the gut. The possibility of the disease being a consequence of infections was ruled out as the use of antibiotics did not aid patients. Angiodysplasia could be an underlying cause of Hughes-Stovin as it can account for the vascular changes. As Hughes-Stovin syndrome is clinically considered an autoimmune disorder, the primary mechanism by which it precedes is presumed to be in the same manner as other autoimmune disorders, the syndrome occurs when the body begins attacking its own cells. This syndrome yields the inflammation of blood vessels in the body due to the body's overreactive immune system targeting affected cells. This causes coagulation, forming blood clots and begins the development of pulmonary aneurysms and thrombosis.
Pathophysiology The etiology or pathophysiology of the disease remains unclear. However, in recent years, Hughes-Stovin syndrome has been found to be potentially caused by systemic venous angiitis or collagen disease. Systemic venous angiitis or vasculitis is an inflammatory disease of the blood vessels walls, secondary to autoimmune diseases. It is essentially a T helper cell driven reaction, recruited by dendritic cells. The vascular impact can affect the blood circulation in the veins and thus give rise to the syndrome of Hughes-Stovin. It can occur in any type of artery or vein and cause the underlying main symptoms prevalent in the disease. This is presumed as Behçet's disease is caused by a similar form of vasculitis, and there is heavy vascular involvement in the disease.
Diagnosis There is no rigid set of diagnostic criteria for Hughes-Stovin. Hughes-Stovin can be discerned from similar conditions by its resemblance to vasculitis without a presenting infection. The syndrome is also identified as being associated with pulmonary/bronchial artery aneurysms and thrombophlebitis, without the known diagnostic symptoms and features of Behçet's disease (BD)." However physicians have often diagnosed Hughes-Stovin syndrome by using one or more of these techniques;
Lab findings Bronchoscopy Ventilation/perfusion scan (V-Q): to examine air circulation in the lungs. Doppler ultrasound of extremities: this is a measure of the amount of blood flow in the body, particularly in the limbs. Radiological diagnosis: a. Chest roentgenograms b. Traditional angiography is often employed to characterize the severity and prognosis of the disease by evaluating the pulmonary aneurysms and assessing the angiodysplasia in bronchial arteries. c. Helical computed tomography d. Magnetic resonance angiography Histological diagnosis: This requires the assistance of a histologist to examine tissue under a microscope in order to diagnose disease. Physicians have to be able to differentiate between HSS and Behçet's disease, as HSS is often clinically considered a rare variant of this disease. The way they do this is through the absence of some of the more common symptoms of Behçet's disease, mouth and genital ulcers. Therefore, in the presence of multiple pulmonary artery aneurysms (PAA) and deep vein thrombosis, physicians differentiate between HSS and Behçet's disease and ultimately rule out Behçet's disease on the basis of the absence of skin-related findings.
Management There is currently no satisfactory treatment for this condition. Immunosuppressive therapy is the most common treatment, involving a mix of glucocorticoids and cyclophosphamide. This is most effective in the early stages and may cause remission of the aneurysms, but is ineffective once the disease has progressed. The administration of corticosteroids, a type of steroid hormones, in combination with cytotoxic agents aid in the stabilization of the pulmonary artery aneurysms. Furthermore, the presence of thrombosis typically would require anticoagulants, however, they are typically not prescribed due to the possible life-threatening rupture of the pulmonary artery aneurysms. Therefore, if anticoagulants are given, this is done in extensive care and in special cases. Depending on the state of the pulmonary artery aneurysms, surgery might also be an option when the aneurysm is localized, this would improve the state of the patient.
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