Microvascular occlusion syndromes Flashcards
(73 cards)
1
Q
HITS epi
A
- 10X higher in unfractionated heparin compared with LMWH
- F>M
- rare in pregnancy
2
Q
HITs pathogenesis
A
- Platelet 4 factor is released and complexes with heparin –> rapid IgG antibody response within 5-7 days develops
- Immune complexes develop –> activating platelets and monocytes
- These activated platelets aggregate and produce platelet microparticles which generate thrombin, and thrombocytopaenia develops
- Activated monocytes and endothelial cells also increase their expression of tissue factor –> thrombin production and vascular occlusion
3
Q
HITS clinical
A
- Timing
- 5-10 days after heparin starts
- if have had heparin in the last 90-100 days, then HITS can develop within hours after re-exposure
- rarely can have anaphylactoid reaction within 30 minutes of a heparin bolus
- Delayed-onset: lesions can occur up to 3 weeks after exposure to heparin
- Atypical scenarios:
- Chronic heparin –> can trigger within 5-10 days
- sometimes without heparin, major surgery or bacterial infections can trigger a spontaneous or autoimmune HIT syndrome
- 5-10 days after heparin starts
- Cutaneous
- Tender, sharply demarcated, non-inflammatory and purpuric or necrotic, retiform
- Can occur at sites of S/C injection, or distant to heparin infusion
- Platelets
- Don’t often get thrombocytopaenia on bloods, although there is a consumption of platelets
- Decline in platelet of >50% from highest count should prompt consideration
- Cx: vascular occlusion to any limb or organ
4
Q
HITS pathology
A
non-inflammatory occlusion of blood vessels and ischaemic necrosis
5
Q
HITS dx
A
You can test: presence of anti-PF4 heparin complex antibodies –> can do via ELISA
6
Q
HITS rx
A
- Cease heparin
- Argatroban: treatment of HITS, is a direct thrombin inhibitor
- Also effective: danaparoid (Xa inhibitor), fondaparinux and bivalirudin
- need anticoagulation for 3 months with non-heparin agent
- Vitamin K blockers are contraindicated: increased risk of developing venous limb gangrene secondary to decreased Protein C
7
Q
Essential thrombocytosis epi
A
- PCV and essential thrombocytosis are more common in women
- > 50 years, incidence increases exponentially after 60 years
- have an increased CVS mortality risk
8
Q
Essential thrombocytosis pathogenesis
A
- essential thrombocytosis followed by PCV more likely to develop
- JAK mutation present in 90-95% of PCV patients, 50-70% of essential thrombocytosis and primary myelofibrosis
- MPL and CALR more commonly in essential thrombocytosis and primary myelofibrosis
- In these disorders, platelets can function abnormally –> occlusion or haemorrhage
- When platelets 400-1000 then thromboembolism is common
- When platelets 1000-2000 then bleeding is more common
- Acquired von Willebrand occurs when the platelet count is >1000
- When the platelet count is within a normal range of a myeloproliferative neoplasm, the risk of thrombosis is uncertain
9
Q
Essential thrombocytosis clinical
A
- Cutaneous in 20% of patients
- Purpura
- Haematomas
- Livedo reticularis
- Erythromelalgia
- Intense burning and paroxysmal bright erythema of the distal extremities
- can occur with any myeloproliferation or myelodysplastic disorder if the platelets are high enough
- platelet mediated acral vasodilation, inflammation and microvascular occlusion
- secondary responds well to aspirin
- Raynaud
- Urticaria
- Vasculitis
- Leg ulcers
- Gangrene
- Superficial thrombophlebitis
- CML often has elevated neutrophil counts, eosinophil or basophil counts
10
Q
Essential thrombocytosis histo
A
- microvascular occlusion of dermal vessels or subcutaneous arterioles
11
Q
Essential thrombocytosis rx
A
- Can give low dose aspirin
- For high risk - >65 with PV or >60 with ET and thrombosis –> low dose aspirin plus cytoreductive therapy
- refractory prutiis in PCV –> paroxetine, interferon alpha, UVB phototherapy, JAK inhibitor
- Imetelstat
12
Q
Paroxysmal Nocturnal Haemoglobinuria pathogenesis
A
- Mutation ins PIG-A in haemotopoietic stem cells - encodes proteins which are responsible for protecting blood cells and platelets from complement mediated injury.
- Lack of protection: red cell lysis and activation of platelets
- X-linked
- Cause of venous thrombosis is multifactorial, due to microparticle formation from platelets and other blood componenet membranes
13
Q
Paroxysmal Nocturnal Haemoglobinuria clinical
A
- Intravascular haemolysis, deficient haematopoiesis and thrombotic tendency
- can occur with aplastic anaemia, myelodysplastic syndrome
- Thrombotic events the most common cause of death, and venous thromboses more common than arterial
- Cutaneous:
- Haemorrhagic bullae
- Petechiae
- Leg ulcers
- Non-inflammatory retiform purpura
- Purpura fulminans like presentation
- Extra-cutaneous: smooth muscle dystonia with dysphagia, abdominal pain and erectile dysfunction, ++ chronic kidney disease
14
Q
Paroxysmal Nocturnal Haemoglobinuria histology
A
- microvascular occlusion
- detection of an absence or severe deficiency of GPI-anchored protein in >2 cell lineages (WCC, RBC) by flow cytometry of peripheral blood is diagnostic of PNH
15
Q
Paroxysmal Nocturnal Haemoglobinuria ddx
A
- haemolytic anaemia + pancytopaenia should suggest PNH
- the ddx is super broad
16
Q
Paroxysmal Nocturnal Haemoglobinuria rx
A
- Eculizumab: inhibits terminal phase of the complement cascade at the C5 stage, and can reduce intravascular haemolysis and venous thrombosis
- this can increase the risk of meningococcaemia via C5 inhibition, so make sure they get the meningococcal vaccine 2 weeks prior
17
Q
Primary thrombotic microangiopathy characterisation
A
- characterised by microangiopathic haemolytic anaemia + thrombocytopaenia
- used to be TTP and HUS, but there are just lots of types of primary and secondary
18
Q
Primary thrombotic microangiopathy inherited subtypes
A
- ADAMTS13 deficiency - TTP:
- onset in childhood
- recurrent TMA, neurologic or other organ
- Rx: plasma infusion or exchange
- Complement mediation
- 90% of inherited cases
- results in uncontrolled activation of the alternative complement pathway
- TMA + renal injury
- Rx: anti-complement: eculizumab, plasma exchange or infusion
- Metabolism mediated - MMACHC mutation
- homocystinuria and methylmalonic aciduria from mutation
- metabolic abnormalities trigger platelet activation
- Occurs in infancy
- Clinical: developmental delay, hypotonia, pulmonary artery hypertension, CKD with hypertension and proteinuria
- Rx: B12, folinic acid, betaine
- Coagulation mediated
- Mutation in THBD, PLG and DHKE - encode thrombomodulin, plasminogen, etc
- results in prothrombosis
- see in infancy
- AKI
- Rx: plasma infusion
19
Q
Primary thrombotic microangiopathy acquired subtypes
A
- ADAMTs12 deficiency
- from autoantibodies leading to inhition of ADAMTS12 activity
- results in vascular occlusion
- Adults: more common in women and blacks
- TMA with thrombocytopaenia, GI symptoms, focal neurological defects, transient renal injury
- Rx: plasma exchange
- Shiga toxin mediated - HUS
- Enteric infection with a toxin secreting strain of E coli or Shigella
- Early childhood
- Infectious enterocolitis, thrombocytopaenia, renal disease
- Supportive care
- Drug mediated - imnune
- Quinines, quetiapine, gemcitabine, interferon-beta
- Adult hood
- Sudden onset of severe systemic symptoms
- Stop the drug!
- Drug mediated - toxic/dose related
- Multiple drugs: cyclosporin, tacrolimus, VEGF inhibitors
- Gradual onset renal failure
- Complement mediated - 10% of cases acquired
- Antibdoies inhibit complement factor H
- Reduced inhibition or allternate complement pathway factors –> vessel damage
- AKI
- Plasma exchange
20
Q
Primary thrombotic microangiopathy clinical
A
- Fever, petechiae, thrombocytopaenia, microangiopathic haemolytic anaemia (schistocytes or framgented red cells prominent on the peripheral smear)
- Renal disease
- Neurologic: headache and confusion
- Macular petechiae: reflect haemorrhage, but occasionally may be from platelet plugging
- Disease may be subclinical unless triggered by factors such as drugs, pregnancy, AI-CT disease, systemic infections, haematopoietic stem cell transplant, malignant hypertension
21
Q
Primary thrombotic microangiopathy histo
A
microvascular occlusion of the visceral terminal arterioles and capillaries
22
Q
Primary thrombotic microangiopathy Ddx
A
- sepsis syndromes
- DIC
- normal or minimally elevated prothrombin time plus profound thrombocytopaenia strongly favours TMA over DIC
- antiphospholipid antibody syndrome
23
Q
What are cryoglobulins
A
immunoglobulins that are present in both serum and plasma, and reversibly precipitate with cold exposure
24
Q
What are cryofibrinogens
A
fibrinogens which precipitate in the cold, are consumed in clotting and therefore detectable only in plasma samples
25
What are cold agglutinins
antibodies which promote agglutination of red cells on exposure to cold
26
Disorders of Cryoprecipitation or Cryagglutination pathogenesis
- cryoglobulins become water insoluble on exposure to the cold --> increased viscosity
- Type 1: occlusion
- Type 2 & 3: immune complex mediated vasculitis --> inflammatory purpura which is palpable
- When cryoproteins precipitate it results in retiform purpura/necrosis --> reflection of monoclonal immunoglobulins --> type 1 from an underlying plasma cell dyscrasia
- Immune complex disease results in inflammatory purpura that is palpable --> usually due to Type 2 or 3, due to HCV
27
Disorders of Cryoprecipitation or Cryagglutination epidemiology
- Cryofibrinogenaemia varies from 0-7% in healthy, and 8-13% in hospitalized
- Female: male is 1.5-4.5:1
- can be secondary to lots of things: carcinomas, infectious, autoimmune
28
Disorders of Cryoprecipitation or Cryagglutination clinical
- Cardinal sign: purpura or necrotic lesions, often retiform, at acral sites of cold exposure
- Other cutaneous:
- acral cyanosis
- Raynaud phenomenon
- livedo reticularis
- Type 1 may have secondary vasculitis
- Type 2 may cause occlusion if they are unstable at close to body temperature
- With cryofibrinogenaemia --> need clinical correlation as its actually quite prevalent.
- Cold agglutinins are often asymptomatic, incidental findings such as mycoplasmal infections
- when symptomatic: haemolysis post cold exposure
- very rarely, cold exposure can result in red cell agglutination in cold-exposed sites
- can occur at infusion sites
29
Disorders of Cryoprecipitation or Cryagglutination histo
- eosinophilic hyaline occlusion of the blood vessels
30
Disorders of Cryoprecipitation or Cryagglutination ddx
- syndromes of distal occlusion: cholesterol emboli, acral antiphospholipid antibody
- Pernio
31
Disorders of Cryoprecipitation or Cryagglutination rx
- minimise cold exposure
- Cryoglobulinaemia:
- control underlying plasma cell dyscrasia or lymphoproliferative disorder
- short term: plasmapheresis or plasma exchange
- Cryofibrinogenaemia:
- low dose aspirin and steroids
- Stanozolol
- Immunosuppressants, plasmapharesis, IV fibrinolysis
- Thrombotic: anticoagulation
- Cold agglutinin:
- cold avoidance
- Rituximab - 50% response rate
32
Cholesterol emboli epi
- Mean >50 years
| - Comorbidities: diabetes mellitus, hyperlipidaemia, hypertension, tobacco use, peripheral artery diease
33
Cholesterol emboli pathogenesis
- severe atherosclerotic disease
- three settings to fragment cholesterol:
- 1. Arterial or coronary catheterization
- 2. Prolonged anticoagulation: slowly lyses the clot, leaving exposed areas of the plaque subject to shear stress of arterial flow. Occurs 1-2 months after starting the therapy - 'warfarin blue toe syndrome'
- 3. Acute thrombolytic therapy - given for MI or stroke, can occur within hours to days
- 20% will have no known inciting event
34
Cholesterol emboli clinical
- Systemic: fever, weight loss, myalgias, altered mental status, sudden onset of arterial hypertension
- Cx: embolic --> TIA, strokes, renal failures, GI ulcerations, haemorrhagic pancreatitis
- Cutaneous:
- Livedo reticualris
- Cyanosis/blue toes - 30-75%
- Ulceration - 15-40%
- Peripheral gangrene
- Nodules
- Purpura
- Can get upper extremity lesions can occur if the plaque originated in the aortic arch
- Initial diagnosis made in only 35-40% of patients
- Ix: eosinophilia, hypocomplementaemia, leukocytosis, elevated ESR, CRP, serum creatinine, BUN, amylase
- Urine: pyuria, eosinophiluria, heme positive urine or stool
35
Cholesterol emboli histo
- Cholesterol emboli: elongated clefts within lumina of small vessels --> clefts are from dissolution of cholesterol crystals during the fixation process
- neutrophils, eosinophils and mononuclear cells in the arterial walls within 24-48 hours, multinucleated histiocytes within 3-6 days (make sense)
36
Cholesterol emboli ddx
- abrupt onset should worry those about cholesterol or oxalate embolism
- retiform purpura, especially when it occurs distally in concert with extensive distal livedo reticularis, is especially suggestive of this diagnosis
- Acral cold occlusion syndromes need to be considered
37
Cholesterol emboli rx
- supportive, if possible surgical bypass or endovascular stent grafting
- aspirin, antiplatelets, statins, discontinuation of anticoagulation
- severe renal damage --> initiation of anticoagulation
- systemic steroids
- iloprost
- hyperbaric oxygen
38
Oxalate Embolus path and epi
- Really rare, occurs in association with primary hyperoxaluria
- rare enzyme deficiency
- increased oxalaic acid accumulation
39
Oxalate Embolus clinical
- Childhood: urolithiasis --> deposits in the kidney --> renal failure
- Once renal failure occurs, then embolus usually occurs
- death by age of 20 is not uncommon
- Secondary or acquired may result from taking oxalate precursors, increased absorption, pyridoxine deficiency, impaired renal excretion or bowel disease (Crohns)
- Cutaneous:
- acrocyanosis
- Raynaud
- peripheral gangrene
- acute cutaneous necrosis
- livedo reticularis
- erythematous ulcerated nodules
- miliary calcified deposites
- cutaneous calciphylaxis like presentation --> can be confusing because also renal failure
40
Oxalate Embolus histo
- yellow-brown birefringent crystals in a rectangular or radial pattern within and around vessels in the deep dermis and subcutaneous tissue
- crystals are yellow to golden brown in routinely stained sections, and birefringent under polarized light
- stain with alizarin red at pH 7
- no calcium deposition
41
Oxalate Embolus ddx
- cholesterol embolus
- cutaneous calciphylaxis
- other retiform purpura and livedo reticularis
42
Oxalate Embolus rx
- Type 1 primary hyperoxaluria without renal failure: oral pyridoxine
- Type 2: hydration and alkalinization of the urine
- no point doing a transplant without fixing the underlying issue
- hepatic transplant may reverse it
43
Atrial myxoma
- are, 3rd - 6th decade of life. Constitutional symptoms: fever, malaise, arthralgia, weight loss, blood flow obstruction, embolic phenomena
- Cutaneous: acral papules, purpuric, serpiginous or annular violaceous fingertip lesions, splinter haemorrhages, livedo reticularis, Raynaud, toe necrosis, malar flush, distal petechiae
- Carney complex: multiple early onset cardiac myxomas
44
Neonatal Purpura Fulminans
- Homozygous deficiency or severe dysfunction of protein C or protein S leads to neonatal purpura fulminans
- Its interesting because if they have deficiency of antithrombin 3 then they get DVTs and PEs but minimal cutaneous findings
- Clinical: non-inflammatory retiform purpura --> large scale cutaneous and limb necrosis, and visceral organ involvement
- Often born with cerebral thrombosis or retinal vessel occlusion with congenital blindness
- Can get acquired from group B strep infections
- Rx: intravenous protein C or fresh frozen plasma as initial treatment, then warfarin or LMWH, followed by tapering of factor replacement. they are then anticoagulated for life
45
Warfarin necrosis
- Abnormal gamma-carboxylation by the liver of vitamin K sensitive factors --> 2, 7, 9, 10, protein C and, could also get from severe vitamin K deficiency
- shortest half lives are factor 7 and protein C --> factor 7 is needed to switch to procoagulation
- so in warfarin necrosis, the procoagulant system takes longer to reach its low point equilibrium than protein C dependant anticoagulation does
- Starts 2-5 days after starting warfarin without heparin, more likely to occur if loading doses occur, and is when the protein C drops
- 4X higher in women, peak incidence 60-70s
- late onset warfarin necrosis is also a thing, for people with poor compliance or inappropriate dosing, liver function alteration or drug interactions
- Clinically:
- areas with lots of subcut fat: breast, hip, buttock or thigh
- pain, followed by well-demarcated erythema --> rapidly becomes haemorrhagic and necrotic
- partial retiform or branching purpura typically can be seen within or at the margin of the cutaneous lesions
- Biopsy: thrombosis of most of the dermal vessels
- Rx: stop warfarin, start vitamin K and heparin, and protein C replacement
46
Warfarin associated venous limb gangrene
- malignancy and HITs --> venous limb ischaemia and gangrene
- malignancy --> platelet consumption and coagulopathy
- INR is elevated as well
- persistent thrombin generation
47
Purpura fulminans with sepsis
- Meningococall infection: meningococcus' ability to bind directly to endothelial receptors via its type 4 pili
- Can also occur with S aureus, HIb and a few others
- In bubs most commonly from GBS
- Septic patient with DIC:
- retiform purpura can be the first sign --> inability of protein C-thrombodulin pathway to prevent clot propagation
48
Purpura fuliminans post infection
- Children post group A strep, varicella zoster or HHV6 --> acquire and antibody that inhibits protein S function
- occurs 7-10 days after initial infection
- Rx: would ideally like to treat with protein S, but there is no such thing really, so trial plasma exchange, plasmapharesis, plasma replacement + LMWH and sometimes IVIG
49
Antiphospholipid Antibody/ Lupus Anticoagulant Syndrome Diagnosis
Diagnosis - Sapporo-Sydney Criteria
You need at least 1 clinical and 1 lab criteria:
Clinical:
1. Vascular thrombosis --> can occur anywhere
2. Pregnancy morbidity
1. 1 or more unexplained foetal death after 10 weeks
2. Or 1 or more premature births of morphologically normal neonates before 34 weeks due to eclampsia/pre-eclampsia/placental insufficiency
3. 3 ore more spontaneous abortions
Lab criteria:
1. Anti-cardiolipin antibodies, IgM or IgG
2. Lupus anticoagulant
3. Anti beta-2 glycoprotein
50
Antiphospholipid Antibody/ Lupus Anticoagulant Syndrome epidemiology
- Females ++
- mean age 42 +/- 14 years
- Primary: 53%, secondary lupus 36%, lupus like sydnromes 5%
- Patients with lupus: more episodes of arthritis, livedo reticularis, thrombocytopaenia, leukopenia
- Females more likely to have arthritis, livedo reticularis, migraines
- Men: MI, epilepsy, arterial thrombosis
51
Antiphospholipid Antibody/ Lupus Anticoagulant Syndrome pathogenesis
multiple mechanisms for anti-phospholipid antibodies mediating thrombosis --> interference with release of prostacyclin, protein C and S pathways, activation of platelets by interacting with platelet membrane phospholipids, etc
52
Antiphospholipid Antibody/ Lupus Anticoagulant Syndrome clinical
- Cutaneous:
- Livedo reticularis - 24%
- Leg ulcers 5.5%
- Pseudovasculitic lesions 3.9%
- Digital gangrene
- Cutaneous necroiss
- Splinter haemorrhages
- Acral livedo reticularis
- Livedoid vasculopathy or Degos-like lesions
- Anetoderma like lesions with microthrombosis
- Raynaud
- Behcet like
- PG like
- Nail fold ulcers
- Pseudo-Kaposi sarcoma
- Extra-cutaneous
- DVT/PE
- CNS
- Catatrophic APLS - precipitated by surgery, drugs, discontinuation of anticoagulants, infections
- Also quite possibly can have seronegative group
53
Antiphospholipid Antibody/ Lupus Anticoagulant Syndrome path and lab investigations
- Antiphospholipid antibodies and lupus anticoagulants are detected by different assays - if positive for both its because they actually probably are
- Lupus anticoagulant
- most specific
- poorly predictive of thrombosis
- Anti-cardiolipin antibodies
- more positive than lupus
- specificity for clinically significant disease is lower
- Histo:
- non-inflammatory thrombosis of small dermal vessels
54
Antiphospholipid Antibody/ Lupus Anticoagulant Syndrome ddx
- in lupus, APLS is particularly likely to present as persistent moderate to extensive livedo reticularis or as livedoid vasculopathy
- Catastrophic may mimic DIC or ADAMTS13 deficiency
- Levamisole adulterated cocaine: neutropenia, aPL antibodies, ANCA
55
Antiphospholipid Antibody/ Lupus Anticoagulant Syndrome rx
- Heparin and chronic anticoagulation
- Aspirin for arterial events or stroke
- Lupus: antimalarial
- Catastrophic: systemic steroids, plasma exchange, IVIG, ritux, cyclophosphamide, eculizumab
56
Sneddon syndrome epi
- F>M
| - third or fourth decade of life
57
Sneddon syndrome pathogenesis
- often considered a manifestation of APLS, but not always positive antibodies
- Distinctive vasculopathy of smaller arteries and larger arterioles - particularly skin and brain
- Significant overlap with autosomal recessive disorder ADA2 deficiency
58
Sneddon syndrome clinical
- persistent, widespread livedo racemosa --> can precede neuro for many years
- labile hypertension
- CNS disease
- Hx foetal loss
- Raynauds
- those who are aPL antibody negative are less likely to have seizures, mitral regurg, thrombocytopaenia but more likely to have larger pattern livedo reticularis
59
Sneddon syndrome histo
- take the biopsy from normal appearing skin the centre of livedo reticularis
- endothelial inflammation, subendothelial myointimal hyperplasia, occlusion (partial or whole) of involved arterioles
60
Sneddon syndrome ddx
- Other livedo racemosa ddx
- ADA2 deficiency --> paeds
- make sure to test aPL antibodies
61
Sneddon syndrome rx
- Warfarin, although not routinely effective
- Systemic steroids or immunosuppressants not helpful either
- in those who are aPL negative, antiplatelets were just as effective so use aspirin/clopidogrel
62
Livedoid vasculopathy epi
- young to middle aged women
- can be divided into:
- Primary
- Secondary --> associated with varicosities, etc
63
Livedoid vasculopathy pathogenesis
- unknown, believed to be alteration in local or systemic control of coagulation with formation of fibrin thrombi focially wihtin superficial dermal blood vessels
- number of prothrombotic factors has been associated with this syndrome lijke protein C and S, factor 5 leiden, etc
64
Livedoid vasculopathy clinical
- painful, persistent and often punched-out ulcerations on the legs --> particularly the malleoli in women
- some patients may develop retiform or stellate purpura or ulcer extension
- heals with white atrophic scars with peripheral telangiectasias
- 50% --> associated prothrombotic abnormality has been noted
65
Livedoid vasculopathy ddx
Antiphospholipid antibody syndrome
| atrophie blanche like lesions: APLS, vasculitis, sickle cell disease, hydroxyurea related leg ulcers
66
Livedoid vasculopathy histo
- mild peri-vascular lymphocytic infiltrate
- extravasated red cells surrounding superficial dermal vessels with hyalinized walls and luminal fibrin deposition
- IF non-specific: IgM, C3 may be within vessel walls
67
Livedoid vasculopathy rx
- anticoagulants as monotherapy
| - other options: anabolic steroids, IVIG, antiplatelets
68
Malignant atrophic papulosis epi
- females, 20s-40s
| - can be familial
69
Malignant atrophic papulosis pathogenesis
- small vessel vasculopathy --> vaso-occlusive disorder
- several diseases can mimic it: APLS, lupus, DM
- Two forms:
- Systemic - dysregulation of interferon alpha and C5-9 membrane attack complex
- Benign - skin limited
70
Malignant atrophic papulosis clinical
- Cutaneous:
- crops of small 2-5 mm erythematous papules on the trunk or extremtiies, these evolve over 2-4 weeks with central depression
- porcelain white scar often with a rim of telangiectasias and appearance similar to atrophie blanche
- typically precede systemic manifestations
- Gastrointestinal: bowl perforation
- CNS manifestations
- Probability of having benign form of disease 70%, after 7 years of skin limited disease then icnreases to 97%
71
Malignant atrophic papulosis histo
- Wedge shaped area of ischaemic dermis with a sparse perivascular lymphohistiocytic infiltrate at the edge of the ischaemic area
- atrophic but slightly hyperkeratotic overlying epidermis
- Oedema and mucin in the ischaemic dermis
- Late stage sclerosis may be seen
- base of lesion: vascular damage with thrombosis
72
Malignant atrophic papulosis ddx
- lupus, DM
| - APLS
73
Malignant atrophic papulosis rx
- no proven treatment for idiopathic
- Aspirin, dipyridamole, eculizumab (decreases C5-9 membrane attack complex deposition) and trepostinil
- Mixed results with IVIG
