Anaphylactoid Purpura And Hereditary Hemorrhagic Telangiectasis
Clinical Features Of Anaphylactoid Purpura
The former is also known as Henoch-Schonlein syndrome, Hypersensitivity angitis and/or Rheumatic Purpura; while the later is also known as Rendu-Osler-Weber syndrome.
This is an immune complex disease caused by type III hypersensitivity reaction similar to that of rheumatic fever and acute glomerulonephritis. Histology shows vasculitis involving the small blood vessels. This syndrome is more common in children but occasionally it may be seen in young adults. Males predominate. In a small proportion of cases, there is history of preceding B-hemolytic streptococcal infection 10 to 20 days prior to the onset of purpura. Other precipitating causes are allergic reactions to drugs and food materials. In many, there may be no evidence of a precipitating cause.
Clinical Causes: A purpuric rash develops acutely over the skin of the extensor surface of the fore-arms, elbows, buttocks and legs distally. The lesions may be urticarial, blotchy and pruritic. Only rarely lesions develop over the trunk and face. Abdominal symptoms such as colicky pain and vomiting are usual. Hematemesis and melena may develop in severe cases. Involvement of joints is common and many large joints are affected. Polyarthralgia, polyarthritis and periarthritis may occur. Hematuria, albuminuria, edema and hypertension are indicative of renal involvement which may develop in 10% of cases. The renal lesions may manifest as acute glomerulonephritis. Some of the cases may develop acute renal failure. A small proportion becomes persistent and progressive.
Blood show neutrophil leucocytosis. Mild eosinophilia may occur at times. Tests of platelet and capillary function are usually normal. Majority of patients recover completely but recurrence may occur on exposure to the allergen.
Treatment: Symptomatic treatement is adequate in most of the cases since the condition is self-limiting in the majority of cases. Prednisolone 1mg/Kg per day gives symptomatic benefit. Steroids should be withdrawn after a short course. Antispasmodics relieve abdominal pain. Steroids have no effect on the skin lesions. If streptococcal sore throat is evident, a course of penicillin is indicated. Immuno-suppressive drugs like azathioprine and cyclophosphamide have been employed when the glomerulonephritis proves to be resistant to steroid therapy.
Drug Induced Vascular purpura
Exposure to drugs like penicillin, sulphonamides, atropine, phenacetin, aspirin and sedatives may produce vascular purpura.
This condition occurs as a chronic disorder of thin elderly people above the age of seventy years. Purpuric and ecchymotic spots occur on the extensor surfaces of the fore arms which arise spontaneously or after unnoticed trauma. The purpura is due to traction injury to the small capillaries of the dermis due to loss of dermal collagen and subcutaneous fat. No therapy is effective in this condition. It is important to distinguish this benign disorder from other diseases which may require therapy.
Clinical Features Of Hereditary Hemorrhagic Telangiectasis
Hereditary Hemorrhagic Telangiectasis
This hereditary bleeding disorder is transmitted as an autosomal dominant and affects both sexes. Multiple telangiectasia are found in the tongue, nasal mucosa, face, lips, conjunctiva, mucus membrane of the gastrointestinal tract and kidneys and over other parts of the skin. Any of these sites may bleed recurrently since the vessels are fragile. Systemic and pulmonary arteriovenous aneurysms have been described. Bleeding leads to anemia, epistacis and hemoptysis. As age advances, the number of lesions increases and bleeding becomes more marked. Diagnosis is made from the typical telangiectasis, bleeding episodes and the family history.
Treatment: Local pressure and application of thrombin help to arrest bleeding. Cauterisation and surgical treatment of arteriovenous fistula are of limited value but may be required at times. Hematinic therapy is indicated to prevent anemia.
Symptomatic Purpura: Several infections cause purpuric manifestation.
- Bacterial infections: Meningococcal septicemia, bacterial endocarditis, leptospirosis and other gram-negative septicemias.
- Viral infections, Measles, influenza, hemorrhagic fever and small pox.
- Rickettsial infections: Typhus and spotted fevers.
- Protozoal infections: Falciparum malaria.
Bleeding is caused by the direct injury to the vascular endothelium by the infecting agent, bacterial embolism or due to vasculitis as in bacterial endocarditis. Other factors like thrombocytopenia and diffuse intravascular coagulation may also be contributory.
© 2014 Funom Theophilus Makama