LEC10 Disorders of Primary Hemostasis Vascular Disorders 1 PDF

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Summary

Hereditary Hemorrhagic Telangiectasia Autosomal dominant Vascular malformation involves vessels throughout the body, which are dilated, tortuous (full of twist) and disorganized. It is characterized by the presence of widespread telangiectatic lesions of the skin and mucous membrane. A.K Osler-Weber...

Description

Hemangioma – Thrombocytopenia Syndrome 1.

Hereditary Hemorrhagic Telangiectasia • •

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Autosomal dominant Vascular malformation involves vessels throughout the body, which are dilated, tortuous (full of twist) and disorganized. It is characterized by the presence of widespread telangiectatic lesions of the skin and mucous membrane. A.K.A Osler-Weber-Rendu Syndrome Lesions develop on the tongue, lips, palate, face and hands IDA is usual Laboratory Findings o Anemia- depending on the degree of bleeding. o BT, PFT, Tourniquet test, Coagulation test – NORMAL o Diagnosis is based on the findings of telangiectasia. Treatment: o Oral iron - anemia o Therapeutic Drugs o Surgical Technique ▪ stop or prevent bleeding Notes: o The vascular defect of this disorder is characterized by thin-walled blood vessels with a discontinuous endothelium, inadequate smooth muscle, and inadequate or missing elastin in the surrounding stroma. o The disorder usually becomes manifest by puberty and progresses throughout life. o Telangiectasias are fragile and prone to rupture. o Epistaxis is an almost universal finding, and symptoms almost always worsen with age. o There are several other disorders and conditions in which telangiectasias are present, including: ▪ cherry-red hemangiomas (common in older men and women), ▪ ataxia-telangiectasia (Louis-Bar syndrome), and ▪ chronic actinic telangiectasia; ▪ they also are seen in association with chronic liver disease and pregnancy.

Kasabach-Merritt Syndrome • Profound thrombocytopenia related to platelet trapping within a vascular tumor, either a Kaposilike hemangioendothelioma or a tufted angioma (tumor of blood vessels that grow in skin). • Thrombocytopenia is usually severe and associated with DIC and MAHA. • Bleeding Diathesis – tendency to bleed • Contributing factors include “platelet trapping” and platelet consumption associated with DIC. • Platelet trapping demonstrated by immunohistochemical staining of the tumors with anti-CD61 antibodies. • Notes: o Originally described the association of a giant cavernous hemangioma (vascular tumor), thrombocytopenia, and a bleeding diathesis. o Treatment: Corticosteroid therapy and surgery

Ehlers-Danlos Syndrome •

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An autosomal-dominant, recessive or x-linked disorder characterized by hyper distensible joints and fragile skin; bleeding is due to abnormalities of collagen in blood vessel walls leading to vascular fragility. Defect – Peptidase enzyme that converts procollagen to collagen. Affected individuals are prone to serious and potentially fatal complications, especially vascular, intestinal, and uterine ruptures. Physical Findings o Large skin ecchymosis and hematomas, bleeding from the gums, GIT bleeding o Laboratory Findings o Coagulation Test: Normal o Platelet count: Normal Treatment o No known therapy Notes: o The disorder generally can be ascribed to defects in collagen production, structure, or cross-linking, with resulting inadequacy of the connective tissues.

Marfan Syndrome •

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Marfan Syndrome is an autosomal-dominant genetic disorder due to mutation of the gene for fibrillin (chromosome 15) resulting in abnormalities of connective tissues and risk for bleeding and bruising. Fibrillin – A glycoprotein that is essential in the formation of elastic fibers found in connective tissue. Affects the bones, lungs, eyes, nervous system, heart, and blood vessels.

Purpura •

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Pseudoxanthoma elasticum • •

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An autosomal recessive disorder affecting elastic fibers of connective tissue of skin and arteries. Genetic disease that causes fragmentation and mineralization of elastic fibers in some tissues. The most common problems arise in the skin and eyes, and later in blood vessels in the form of premature atherosclerosis. o Atherosclerosis – plaque build up in the arteries PXE is caused by autosomal recessive mutations in the ABCC6 gene on the short arm of chromosome 16. Laboratory Findings o Test usually are not helpful in the diagnosis except to rule other causes of the clinical abnormalities. Treatment o No known therapy

Osteogenesis imperfecta •

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A rare autosomal dominant disorder caused by mutation of genes which code for peptides of type 1 collagen; individuals may demonstrate easy bruising, epistaxis, hemoptysis and intracranial bleeding. Diagnosis: X-ray, DNA test, bone density scan Symptoms: Curved spine, loose joint, easily broken bones, and muscle weakness

Clinical manifestation of red blood cell extravasation (leakage) into mucosa or skin, results from various conditions, including rheumatologic, infectious, dermatologic, traumatic and hematologic disorders. Refers to visible hemorrhage into mucous membrane or skin, which corresponds to extravasation of RBC around dermal small vessels and chronic hemosiderin deposition.

Allergic Purpuras / Anaphylactoid Purpura • This is a syndrome characterized by a relatively distinctive purpuric eruption in association with various constitutional and localized symptoms. • Nonthrombocytopenic purpura o Characterized by allergic manifestation – skin rash and edema • Associated with certain foods, drugs, cold, insect bites. • The disorder is the result of an autoimmune process or allergic vasculitis. o e.g. Henoch-Schonlein Purpura • Henoch- Schönlein Purpura o Result of allergic vasculitis which involves the skin, GIT, kidneys, heart and CNS. o It is considered as an immune complex disease and is characterized by involvement of capillaries with diffuse infiltration of neutrophils, lymphocytes and macrophages. o It is commonly seen in children; renal dysfunction is common and typically reversible in children. o Disease of children, occurring most commonly in children 3 to 7 years of age. o The onset of the disease is sudden, often following an upper respiratory tract infection. o Attempts have been made to implicate a specific infectious agent, particularly b-hemolytic streptococcus. o The lesions have been described as “palpable purpura.” o Proteinuria and hematuria are commonly present. o Classic triad: purpura, abdominal pain, and arthritis o Treatment: Corticosteroid – alleviates the symptoms • Notes: o The platelet count is normal. o Tests of hemostasis, including the bleeding time, and tests of blood coagulation, usually yield normal results in patients with allergic purpura o Anemia generally is not present unless the hemorrhagic manifestations have been severe. o The white blood cell count and the erythrocyte sedimentation rate are usually elevated.

Purpura Secondary to Dysproteinemia

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Purpura Associated with Infections • A wide variety of infections may produce purpura by means of vascular damage which result from direct endothelial injury by the infectious agent e.g. Ricketsia, viruses, cocci. a.

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Septic emboli to the skin (Ecthyma gangrenosum) may be seen in endocarditis. • Caused by P. aeruginosa. • Septic means infected with bacteria. • An embolus is anything that moves through blood vessels until it gets stuck in a vessel that’s too small to pass through and stops the blood flow. • Septic emboli are bacteria containing blood clots that have broken free of their source and traveled through the bloodstream until getting lodged in — and blocking — a blood vessel. • The problem with septic emboli: o Septic emboli represent a twopronged attack on your body: ▪ They completely block or partially reduce blood flow. ▪ The blockage includes an infectious agent. o Septic emboli can have mild outcomes (minor skin changes) to serious ones (lifethreatening infections).

Purpura fulminans • A unique disorder characterized by sudden onset, fever, prostration, symmetric circumscribed ecchymoses and infarcts of the skin and frequently by gangrene of the extremities. • The major initiating factor appears to be diffused vascular injury and intravascular coagulation. • The term purpura fulminans applies to any purpura on rapid onset. • More fatal • Treatment: Antibiotic therayi, IV-IgG

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Waldenstrom’s purpura • A disorder of women that presents with recurrent purpura on the lower extremities and resultant hemosiderin staining of the skin similar to Schamberg’s. • Fatigue, weight loss, and enlargement of lymph nodes

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Cryoglobulinemia • Cryoglobulinemia is caused by production of cryoprecipitable serum proteins or protein complexes (result from primary plasma cell dyscrasias or from hepatitis C). • Caused by the abundance of cyroglobulins. • Cryoglobulins are abnormal protein. o Clumps at...