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home - Miscellaneous - Rheumatological Disease - HHT Written by Dr Sebastian Zeki

HHT

AD Cerebral AVMsThese are telangiectasias and AVM’s on the cerebrum or spinal cord.Cerebral AVMs affect 10 % of HHT patients and are usually silent.Bleeding is less likely than in non-HHT cerebral AVMs, in part due to the lower frequency of associated aneurysms.It may be wise to screen for cerebral AVM's with MRI.Treatment involves embolectomy, surgical removal, or stereotactic radiotherapy. EpistaxisThis is the most common clinical manifestation.It is usually the first sign-appears in childhood.If severe, it may need packing. Gastrointestinal bleedingThis occurs in 30%.Patient are usually over 40.Iron deficiency in HHT is more likely due to epistaxis.Telangiectasia occurs most commonly in the stomach and duodenum.Patients also get arteriovenousmalformations (AVMs) and aneurysms. Mucocutaneous telangiectasiaThis occurs in 75%.It presents after the age of 20.It increases in size and number with age. Pulmonary AVMsThese are usually symtpomatic after puberty.These communicate between pulmonary and systemic circulations, leading to hypoxaemia.They are asymptomatic in 2/3rds.They can result in paradoxical emboli.They can cause a haemothorax or haemoptysis- this usually occurs in pregnancy.They may be associated with an increased incidence of migraines.Treatment: involves embolotherapy. Hepatic involvementThis occurs in 30 % - it is usually silent.Patients can get CHF, PHTN, and biliary disease, depending on vascular involvement. Curacao diagnostic criteria1. Spontaneous and recurrent epistaxis2.Multiple mucocutaneous telangiectasias3.Visceral involvement (eg, gastrointestinal, pulmonary, cerebral, or hepatic AVMs)4. A first-degree relative with HHTConfirmed by genetic testing Screening:1. Screening for cerebral AVMs- not recommended as no treatment2. Screening of family members- genetic testing/ pumonary AVM testing +/- cerebral AVM testing Bleeding ManagementAvoid cauterisation as get vascular regrowth. -50 mcg of ethinylestradiol + 1 mg norethisterone po can be useful.- A 0.1 % estriol ointment applied twice daily to the nasal mucosa is beneficial.-"Hormone replacement" range oestrogens: (>625 mincrog/day ethinylestradiol equivalent) have some benefit.Antifibrinolytics such as tranexamic acid and aminocaproic acid can be useful.Antiestrogens such as tamoxifen may be useful.Angiogenesis inhibitors: (eg the VEGF antagonist bevacizumab) are under investigation. 5 major gene products implicatedOver 600 mutations found HHT-1 HHT-2 Chromosome 9: 2 major disease genes on (ENG, protein product: endoglin) Chromosome 12 (ACVRL1, protein product: activin receptor-like kinase 1, ALK-1). Chromosomes 5 (HHT3) and 7 (HHT4). Modulate signalling via (TGF)-beta Endoglin and ALK-1 are transmembrane glycoproteins on vascular endothelial cells. Pulmonary and cerebral AVMs are more common in HHT1 Hepatic AVMs, hepatic AVM- associated pulmonary hypertension and pulmonary arterial hypertension are more common in HHT2. Endoglin ALK-1 IncidenceIt is 1:8000.It is higher in Afro-Caribbean residents of Curacao and Bonaire- 1:1330 Management In Pregnancy Pregnancy is usually safe but consider as high risk.Epidurals are risky (risk of spinal AVM’s).Avoid long 2nd stage if cerebral AVMs have not been excluded. Hereditary Haemorrhagic Telangiectasia Oestrogens- PHTN and encephalopathy caused bya. Hepatic artery- portal vein shunt can cause b. Increased sinusoidal blood flow with enhanced deposition of fibrous tissue and pseudocirrhosis of the liver.Dx: CT, MRI, Doppler ultrasonography, or angiography.Treatment: Do not embolize as get fatal hepatic necrosisIf get liver failure or heart failure, need a liver transplant Written by Dr Sebastian Zeki

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