Vascular malformations Notes

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This Osmosis High-Yield Note provides an overview of Vascular malformations essentials. All Osmosis Notes are clearly laid-out and contain striking images, tables, and diagrams to help visual learners understand complex topics quickly and efficiently. Find more information about Vascular malformations by visiting the associated Learn Page.
NOTES NOTES VASCULAR MALFORMATIONS GENERALLY, WHAT ARE THEY? PATHOLOGY & CAUSES ▪ Developmental malformations of the vascular system SIGNS & SYMPTOMS ▪ Usually asymptomatic ▪ Large malformations can cause obstruction /impair organ functions ▪ Diverts away high volume of blood → heart compensates → high-output heart failure DIAGNOSIS DIAGNOSTIC IMAGING ▪ Imaging studies usually not needed OTHER DIAGNOSTICS ▪ History ▪ Physical examination TREATMENT ▪ Generally no need for treatment unless formations bleed/cause other problems SURGERY ▪ Surgical/laser therapy considered for skin malformations Figure 22.1 Illustration depicting changing pressure between normal arteries and veins. OSMOSIS.ORG 145
ARTERIOVENOUS MALFORMATION osms.it/arteriovenous-malformation PATHOLOGY & CAUSES ▪ Abnormal capillary bed formation between artery and vein ▪ Capillary bed does not form, leaving arteries connected directly to veins → tangling → nidus ▪ Arteriovenous fistula: single artery to single vein direct connection ▪ No capillaries → arteries, veins subjected to high pressures → arteries dilate → veins thicken (fibrosis) ▪ AVM expands over time → compresses surrounding tissues → decreases blood flow ▫ Can cause bruit (whooshing noise heard on auscultation) ▫ Noise can get loud enough that person with the bruit can hear it, causing psychological stress, hearing issues and sleep issues CAUSES ▪ Possibly congenital/genetic ▪ Osler–Weber–Rendu disease/hereditary hemorrhagic telangiectasia connected to AVM RISK FACTORS ▪ Biological male, 10–30 years old, genetic conditions (e.g. Osler-Weber-Rendu) COMPLICATIONS ▪ Ischemia at site, high output heart failure, rupture, haemorrhage SIGNS & SYMPTOMS ▪ Most are asymptomatic ▪ Depend upon location ▪ Presence of bruit on auscultation 146 OSMOSIS.ORG Brain ▪ Epilepsy, neurological deficits, abnormal sensations (numbness, tingling, pain) ▪ Sudden onset, severe headache indicates subarachnoid hemorrhage ▪ Difficulty with movement coordination, muscle weakness, paralysis, vertigo ▪ Apraxia (physical difficulties performing actions upon command, though command is understood) Lungs ▪ Asymptomatic 1/3 of time ▪ Dyspnea, cough, clubbing, cyanosis, hemoptysis, chest pain ▪ Platypnea (shortness of breath in upright position, relieved by lying down) ▪ Orthodeoxia (decrease in oxygen saturation by ≥ 2% when rising from lying down to standing) Spine ▪ Muscle weakness, paralysis Pediatric ▪ May present with ▫ Heart failure, macrocephaly, prominent scalp veins DIAGNOSIS DIAGNOSTIC IMAGING Angiography ▪ Functional anatomy of AVM ▫ Feeding arteries: stenosis ▫ Sharp twisting of veins (ectasia) ▫ Arterial and venous dilatation CT scan/MRI ▪ Anatomy of AVM ▫ Irregular/bulbous masses in brain/ brainstem
Chapter 22 Vascular Malformations OTHER DIAGNOSTICS ▪ Bruit TREATMENT ▪ Treat all arteriovenous malformations SURGERY Radiosurgery ▪ Radiation beams target AVM to close vessels Endovascular embolization ▪ Catheter placed to obstruct vessels Figure 22.2 CT scan of the head in the axial plane demonstrating an arteriovenous malformation in the left parietal lobe. CAVERNOUS HEMANGIOMA osms.it/cavernous-hemangioma PATHOLOGY & CAUSES ▪ Benign tumor formed from tangle of unencapsulated, dilated, thin-walled blood vessels ▪ Spherical caverns form from dilatation of vessels separated by fibrous connective tissue ▪ Characteristic “mulberry” presentation TYPES RISK FACTORS ▪ Von Hippel–Lindau disease COMPLICATIONS ▪ ▪ ▪ ▪ Rupture → hemorrhage Obstructive jaundice, clotting disorders Intravascular thrombosis Dystrophic calcifications SIGNS & SYMPTOMS Cerebral cavernous malformations ▪ Usually asymptomatic Liver cavernous hemangioma ▪ Sometimes found in people with previous pregnancies → high estrogen levels thought to be a factor Brain ▪ Brain tissue compression → seizures, hemorrhages ▪ Stroke, speaking difficulties, memory/ attention difficulties ▪ Headaches, balance issues Ocular cavernous hemangioma CAUSES ▪ Genetic mutations ▫ CCM1, CCM2, CCM3 Liver ▪ Pain in right upper quadrant ▪ Gastrointestinal issues: nausea, vomiting, loss of appetite, early fullness after eating OSMOSIS.ORG 147
Eyes ▪ Double/decreased vision, proptosis DIAGNOSIS DIAGNOSTIC IMAGING MRI ▪ Seen as popcorn/mulberry shape → pathognomonic ▪ Hepatic cavernous hemangiomas best diagnosed with ▫ Ultrasound ▫ IV contrast CT scan ▪ Can be mistaken for metastatic tumors Figure 22.3 Abdominal CT scan in the axial plane showing a hemangioma of the liver. 148 OSMOSIS.ORG TREATMENT ▪ Monitoring usually sufficient MEDICATIONS ▪ Facial hemangioma growth slowed with steroids ▫ Administered orally/injected at site Sclerotherapy ▪ Close tumor’s blood supply → tumor shrinks SURGERY ▪ Prevent damage to healthy tissues Figure 22.4 A cavernous hemangioma from the liver, composed of large vascular spaces with thin walls. No normal liver is present.
Chapter 22 Vascular Malformations HEMANGIOMA osms.it/hemangioma PATHOLOGY & CAUSES ▪ Hemangioma/infantile hemangioma (IH): benign vascular skin tumor ▫ Originates from endothelial cells lining blood vessels ▪ Most frequent tumors of infancy ▪ Develop a few days after parturition ▫ If IH appears to be present at birth → not IH RISK FACTORS ▪ ▪ ▪ ▪ Intrauterine hypoxia Localised hypoxia Biological females more at risk Premature underweight infants COMPLICATIONS Usually none Easily infected, start bleeding Possible ulceration → infection Usually psychosocial: mostly appear on highly visible areas (face, neck, etc.) ▪ Multiple IH in newborns can indicate liver hemangiomas ▪ ▪ ▪ ▪ SIGNS & SYMPTOMS ▪ Appear in first weeks of life ▪ Tumors can grow for ≤ six months after birth ▪ Most regress over time, around five years old ▫ Can leave marks: fibroadipose tissue, changes in pigmentations, scars ▪ Resemble red/white patch, blemish; can be found all over body ▪ Superficial lesions: bright red, flat/raised from the skin → papules AKA “strawberry hemangiomas” ▫ Exposed areas: if grazed, can produce black, crusted, sometimes painful ulceration ▫ > five hemangiomas → ultrasound for hepatic hemangioma ▪ Deeper hemangiomas: bluish lesions, poorly defined ▫ Can proliferate into bigger tumors ▫ Some have superficial capillary counterparts visible over/surrounding affected area ▫ Slower development ▪ Compound hemangiomas: deep IH + superficial IH DIAGNOSIS DIAGNOSTIC IMAGING ▪ Usually no need for imaging Doppler ultrasound ▪ High vessel density and high peak arterial Doppler shift, may show peripheral feeding vessels MRI ▪ Multiple high signal intensity lobules (due to cavernous/cystic spaces containing stagnant blood); often heterogeneous LAB RESULTS ▪ Usually no need for biopsy unless history unclear; used to confirm diagnosis OTHER DIAGNOSTICS History and physical exam ▪ History of onset, age, growth pattern, duration, treatment OSMOSIS.ORG 149
TREATMENT ▪ Most do not require treatment, regress in a few years ▪ Exceptions ▫ Functional issues: feeding (laryngeal hemangiomas), obscuring vision ▫ Bleeding ▫ Hepatic/cardiac complications ▫ Permanent scars causing disfigurement Figure 22.5 A capillary hemangioma on the abdomen of an infant. MEDICATIONS ▪ Beta blockers, oral corticosteroids ▪ Antiangiogenic therapies ▫ Usually intravenous: interferon-alfa 2a, 2b, vincristine SURGERY ▪ Rarely, surgery/laser therapy Figure 22.6 Histological appearance of a capillary hemangioma showing multiple small vascular spaces containing red blood cells. LYMPHANGIOMA osms.it/lymphangioma PATHOLOGY & CAUSES ▪ Benign lymphatic malformations ▪ Composition: lymphatic channels/cysts ▪ May present at birth/develop during first few years of life TYPES Cystic hygroma (macrocystic) ▪ AKA cavernous lymphangiomas ▪ Composition: cystic masses, dilated lymphatic networks with thin endothelial 150 OSMOSIS.ORG layer; fluid-filled cavities; indistinct margins ▪ One/more cysts ≥ 2cm3/0.8in3 in size ▪ Tends to develop in deep soft tissues; propensity for rapid growth, local invasion of muscle, bone, underlying tissue Lymphangioma circumscriptum (microcystic) ▪ AKA simple/capillary lymphangioma ▪ Composition: capillary-sized endotheliallined lymphatic networks ▪ One/more cysts < 2cm3/0.8in3 in size ▪ Tend to develop in superficial tissues
Chapter 22 Vascular Malformations Mixed ▪ Contains variously-sized cysts CAUSES DIAGNOSIS DIAGNOSTIC IMAGING ▪ Failure to form communication between lymphatic, venous circulation (e.g. jugular lymph sac, internal jugular vein) during fetal development ▪ May be sporadic/associated with genetic mutations (e.g. VEGFR3 germline mutation) MRI ▪ Multiloculated fluid-filled cystic lesions; identifies lesion’s extent RISK FACTORS Histopathology ▪ Cystically dilated channels lined with flat endothelial cells, filled with lymphatic fluid; deeper vessels are large, contain smooth muscle ▪ Chromosomal anomalies ▫ Turner syndrome, Down syndrome, Noonan syndrome (cystic hygroma) Ultrasound ▪ Prenatal cystic mass detection; ↑ nuchal translucency (hypoechoic space) COMPLICATIONS ▪ ▪ ▪ ▪ Lymphedema, recurrent cellulitis Disfigurement Lesion recurrence Fetal hydrops, fetal death, obstructed labor, chylous pleural effusion, chylopericardium, airway compression (cystic hygroma) SIGNS & SYMPTOMS TREATMENT SURGERY ▪ Resection OTHER INTERVENTIONS ▪ Image-guided percutaneous chemoablation ▪ Sclerotherapy Cystic hygroma ▪ Large (up to 15cm/5.9in), poorly-defined soft, fluctuant mass ▫ Commonly located in deeper layers of cervicofacial region, axilla, lateral chest wall ▫ Covered with normal skin Lymphangioma circumscriptum ▪ Slightly elevated lesion ▫ Commonly located in head (oral cavity), trunk, proximal extremities, axillary region ▫ May appear as translucent/hemorrhagic vesicles ▫ Overlying skin may be reddish-purple color secondary to small hemorrhages, thrombus formation/may contain wartlike lesions Figure 22.7 CT scan in the coronal plane demonstrating a large cystic hygroma on the left side of the neck. OSMOSIS.ORG 151
Figure 22.8 Histological appearance of a lymphangioma composed of dilated lymphatic spaces, lined by simple endothelium. 152 OSMOSIS.ORG

Osmosis High-Yield Notes

This Osmosis High-Yield Note provides an overview of Vascular malformations essentials. All Osmosis Notes are clearly laid-out and contain striking images, tables, and diagrams to help visual learners understand complex topics quickly and efficiently. Find more information about Vascular malformations by visiting the associated Learn Page.