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X NOVEM- OCTO- MONTH library at www . ausdoc . com . au / therapy-update
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2022
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serological tests . In Australia , most laboratories use a treponemal test to screen for syphilis ( eg , syphilis CMIA , enzyme immunoassay [ EIA ]). 1-3 If reactive , a second treponemal test and a non-treponemal test ( eg , RPR ) are performed . 1 , 2 Treponemal tests usually become reactive 2-4 weeks post-infection and usually remain reactive for life , even after appropriate treatment . Non-treponemal tests usually become reactive 3-4 weeks post-infection and indicate disease activity . 2 , 3 Both types of tests do not have 100 % sensitivity and therefore may be negative in early infection ( ie , incubating and primary syphilis ). 1 , 2 The sensitivity of RPR in secondary syphilis is virtually 100 %, however false negatives can occur , as seen in this case , due to the prozone phenomenon .
The prozone effect can be unmasked by diluting the serum to reduce the concentration of circulating antibodies . 4 , 6 When clinical findings are strongly suggestive of syphilis despite negative or unexpectedly low non-treponemal test results , request that the investigating laboratory repeat the test on specimens at higher dilution to uncover a possible prozone effect .
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Management
The patient declines lumbar puncture and is treated presumptively with a neurosyphilis regimen of benzylpenicillin 24 million units
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months after treatment and is reactive , titre 1:64 , indicating successful serological response to treatment .
Acknowledgements The authors wish to acknowledge Associate Professor Bernard Hudson , director of microbiology and senior staff specialist , Royal North Shore Hospital , Sydney , NSW .
References on request from kate . kelso @ adg . com . au
Box 1 . Key practice points
• Syphilis diagnoses are increasing , especially in gay , bisexual and other men who have sex with men ( GBMSM ), Aboriginal and Torres Strait Islander people and women of reproductive age .
• Diagnosis and disease staging of syphilis relies heavily on clinical suspicion and serological tests .
• Consider the possibility of the prozone effect in cases that are highly suspicious for syphilis but with non-reactive or unexpectedly low non-treponemal tests .
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ANSWER The answer is B . Angiosarcomas are malignant tumours that arise from endothelial cells of blood or lymphatic vessels . They are primarily found in the skin and soft tissues on the head and neck of elderly males ; however , they can also originate from solid organs , such as bone , breast , liver and heart . 1
Cutaneous angiosarcoma is the most common type , with most occurring on the upper head and scalp . Lower face and neck presentations are less common . 2
Diagnosis can be difficult because early lesions may appear as innocuous patches of dusky-coloured skin — similar to a poorly defined bruise . Initial lesions can be overlooked , especially in elderly patients taking blood thinners , in whom bruising is common . Lesions can then grow rapidly and become firm , ulcerate and bleed . The diagnosis is confirmed histologically — ideally , on an excisional biopsy . 3
Other differential diagnoses to consider include reactive and benign vascular tumours , such as haemangiomas and pyogenic granulomas . 4
Treatment depends on the location and extent of the lesion but can involve a combination of surgery , chemotherapy and radiotherapy . Radical surgical resection is often attempted , but local recurrence is common owing to extensive microscopic spread of the disease . 1 , 2
Overall prognosis of angiosarcoma is poor as local recurrence , tumour invasion and / or metastasis are common . Reported five-year survival is approximately 35 %, with half of patients dying within 15 months of presentation . 5
References on request from kate . kelso @ adg . com . au
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