Low-molecular-weight heparin-induced skin necrosis

 We report a case of low-molecular-weight heparin (LMWH)-induced skin necrosis in a patient with chronic lymphatic leukemia. The patient had heparin-PF4 antibodies and the heparin-induced platelet activation (HIPA) test was positive, but platelet counts remained normal. Analysis of seven cases of LMWH-induced skin necrosis revealed that this complication occurred mostly in patients previously exposed to heparin, and that severe problems such as thrombocytopenia or thromboembolic complications were rare. This is in contrast to skin necrosis induced by unfractionated heparin (UFH), where a substantially higher number of patients suffered from thrombocytopenia and thromboembolism. In addition, most patients with UFH-induced skin necrosis were not pretreated with heparin. Therefore, it is possible that LMWH is less immunogenic than UFH and requires repeated exposure for induction of skin necrosis. Received: February 18, 1998 / Accepted: May 11, 1998     

Heparin-induced skin necrosis associated with thrombocytopenia and acquired protein C and protein S deficiency

We have described a patient with colon cancer and liver metastases who developed heparin-induced thrombocytopenia and skin necrosis. We believe that the skin necrosis caused by the heparin/platelet factor 4 antibody was exacerbated by the acquired protein C and protein S deficiency. After the heparin was discontinued and infection treated, the skin necrosis and thrombocytopenia resolved. This case illustrates the fact that, in patients with heparin-induced skin necrosis, a search must be undertaken for an underlying pro-thrombotic state, which may precipitate the microthrombosis responsible for skin necrosis. We could not find any previous case reports of heparin-induced skin necrosis associated with isolated protein C deficiency, or combined protein C and protein S deficiency.     

Warfarin‐induced skin necrosis associated with Factor V Leiden and protein S deficiency

Thrombotic events are rare complications during anticoagulation therapy. The thrombosis varies from localized cutaneous involvement to catastrophic thromboembolism and is usually associated with an underlying thrombophilia. We describe a patient who developed skin necrosis during warfarin treatment for a pulmonary thromboembolism. The management was complicated by the development of heparin‐induced thrombocytopenia and further thrombotic events. Thrombophilia screen demonstrated the presence of protein S deficiency and Factor V Leiden as the prothrombotic factors, together with the demonstration of antiplatelet factor 4 antibodies, which confirms the diagnosis of heparin‐induced thrombocytopenia (type II). Reinstitution of warfarin at a low loading dose was successful without the recurrence of skin lesions nor any further thrombosis.     

Heparin‐induced thrombocytopenia in myeloproliferative disorders: A rare or under‐diagnosed complication?

Patients with myeloproliferative disorders (MPD) are prone to develop thrombotic complications and thus frequently receive heparin. Surprisingly heparin-induced thrombocytopenia (HIT) has been rarely reported in MPD and is potentially under-diagnosed due to the relatively high platelet count. We report three patients with MPD who developed HIT; all presented with a relative fall of platelet counts (although without an absolute thrombocytopenia), thrombosis or skin necrosis and a positive test for HIT antibodies (particle gel immunoassay). Risk factors for developing HIT in our patients were exposure to unfractionated heparin, a recent surgical procedure and female gender. We review the literature on HIT in MPD and discuss the diagnosis of HIT in the absence of an absolute thrombocytopenia.     

A fatal case of enoxaparin induced skin necrosis and thrombophilia

Skin necrosis caused by heparins is a rare complication. We report a case of a 71-yr-old white woman who developed painful diffuse skin lesions, most probably related to enoxaparin treatment. Other causes of skin necrosis, including heparin induced thrombocytopenia, disseminated intravascular coagulation, protein C/protein S deficiencies, anti-phospholipid antibodies, and vitamin K deficiency were less likely in this case. The concomitant combined thrombophilia possibly aggravated the patient's clinical presentation.     

Anticoagulant-induced skin necrosis in a patient with hereditary deficiency of protein S

Skin necrosis is a rare but debilitating complication of treatment with vitamin K antagonist anticoagulants such as warfarin. A clinically similar syndrome has been reported less frequently with heparin therapy. We recently managed a thirty-year-old female patient who developed skin necrosis on her left lower extremity while on warfarin for postpartum DVT. The lesions started to develop 48 hr after stopping heparin therapy. Discontinuation of warfarin and reinstitution of heparin was complicated by a rapid decrease in platelet count consistent with heparin-induced thrombocytopenia (HIT) and its associated risk of platelet activation and thrombosis. The diagnosis was supported by the identification of antibodies against heparin/platelet factor 4 complexes in the patient's serum. The platelet count recovered and the patient improved after switching to therapy with the heparinoid danaparoid. Evaluation for a hypercoagulable state revealed a partial deficiency of protein S, a condition that previously was identified in two of her family members. It is not clear if this patient suffered from warfarin-induced skin necrosis, a manifestation of heparin-mediated platelet activation, or a complex condition in which both drugs contributed. HIT may affect 1-3% of patients who receive unfractionated heparin, and this case raises the possibility that heparin may contribute to, or cause, some episodes of skin necrosis attributed to warfarin. Because many patients who develop warfarin-induced skin necrosis have been treated initially with heparin, it would seem prudent to consider HIT in these situations.     

Leucocytoclastic Vasculitis and Skin Necrosis Following Subcutaneous Heparin Calcium

Abstract: Leucocytoclastic vasculitis and skin necrosis following subcutaneous heparin calcium. J. H. Kearsley, R. W. Jeremy and A. S. Coates, Aust. N.Z. J. Med. , 1982, 12, pp. 288–289.
Low dose heparin calcium is of proven value in the prevention of post-operative deep venous thrombosis, and has been shown to reduce the incidence of fatal pulmonary embolism/ Adverse local reactions, most commonly haemorrhage, are seldom troublesome, but we report here a patient in whom extensive skin necrosis occurred at the sites of subcutaneous heparin calcium injection.     

Treatment of massive arterial thrombosis caused by thrombocytopenia induced by heparin with local thrombolysis

The authors report the case of a patient treated by subcutaneous injection of calcium heparin after deep vein thrombosis with floating thrombus and pulmonary embolism. She was readmitted to hospital after 16 days' treatment because of a massive aorto-iliac thrombosis due to heparin-induced thrombocytopenia (platelet count = 29.000). This thrombosis was treated by local injection of Urokinase (total dose = 7.425.000 U) over 93 hours without any major complications. The aorto-iliac circulation was completely restored to normal after treatment. Thrombotic complications secondary to immuno-allergic heparin-induced thrombocytopenia are relatively common because of the widespread use of heparin. From the therapeutic point of view, it is imperative to stop the heparin, which makes surgery very difficult, and the platelet-fibrin composition of these thrombi suggests that local thrombolysis with Urokinase is the treatment of choice in this syndrome.     

The use of low dose Orgaran in heparin-induced thrombocytopenia associated with in vitro platelet aggregation at higher Orgaran concentrations

We report a case of heparin-induced thrombocytopenia with in vitro antibody cross-reactivity by platelet aggregometry to both low molecular weight heparin and the heparinoid Org 10172 (Orgaran). The in vitro reactivity with Orgaran was only present at the upper limit of concentrations that would normally be used therapeutically. Low dose Orgaran therapy was initiated, allowing successful renal replacement therapy without invoking further thrombocytopenia or thrombosis. Interestingly, in vitro platelet aggregometry following treatment did not reveal increasing sensitivity to Orgaran. This case indicates that negative in vitro platelet aggregometry at defined lower concentrations of Orgaran may predict in vivo safety at the same levels despite positive platelet aggregometry reactions at higher concentrations of Orgaran.     

Calciphylaxis: a case study with differential diagnosis

Calciphylaxis is a relatively rare, but horribly disfiguring, skin condition that is most often associated with end-stage renal disease and long-term dialysis. Unfortunately, calciphylaxis-related morbidity and mortality are significant. The case study presented demonstrates many of the findings associated with the typical calciphylaxis patient; end-stage renal disease and an extensive, painful ulcer. The complexity of the patient s history and medical/surgical interventions, especially medication therapy with coumadin and heparin, complicated initial diagnostic processes. Close scrutiny of multiple physical assessment findings, historical factors, and test results was required for correct diagnosis. Crucial components of differential diagnosis of calciphylaxis versus coumadin-induced skin necrosis or heparin-induced thrombocytopenia necrosis include: patient history and characteristics, clinical presentation, and diagnostic test results.     

Use of recombinant hirudin as antithrombotic treatment in patients with heparin-induced thrombocytopenia

Heparin-induced thrombocytopenia is a rare but severe complication of heparin therapy that can result in severe venous or arterial thromboembolic events and whose treatment remains partially unanswered. Recombinant hirudin is potentially effective as an antithrombotic treatment in the management of heparin-induced thrombocytopenia, given its potent antithrombin effects without known interaction with platelets. We report the results obtained with intravenous recombinant hirudin (HBW 023) administered on a compassionate basis to patients suffering from heparin-induced thrombocytopenia. Six patients suffering from heparin-induced thrombocytopenia were submitted to intravenous recombinant hirudin (HBW 023) administered at a dose of 0.05 mg/kg/hr after an initial bolus injection of 0.07 mg/kg in the case of a venous thromboembolic event, and at a dose of 0.15 mg/kg/hr with the same initial bolus injection in the case of an arterial thromboembolic event. Whenever possible, oral anticoagulation with acenocoumarol was introduced at the same time as recombinant hirudin, which was interrupted as soon as the international normalized ratio reached 3. Clinical events, particularly thromboembolism and bleeding, were noted; activated partial thromboplastin time (aPTT), and platelet count were assessed throughout the administration of recombinant hirudin. Heparins responsible for heparin-induced thrombocytopenia were porcine sodium or calcium heparinate in four cases, nadroparin in one case, and enoxaparin in one case. Thrombocytopenia was discovered on routine systematic platelet count in two patients and after the occurrence of arterial and venous thromboembolism in two patients, respectively. After discontinuation of heparin and the onset of recombinant hirudin, clinical evolution was uneventful in all patients, with no recurrence of thromboembolism, limb amputation, or hemorrhagic complication. The aPTT ratio varied from 1.8 to 3.5 (median 2.4) throughout administration of recombinant hirudin. Platelet count rose from nadir (median value 60 × 10⁹ 15 to 90) to above 100 × 10⁹/L in every patient within 3–6 days (median 5), after discontinuation of heparin. Intravenous administration of recombinant hirudin ensured safe anticoagulation in patients with heparin-induced thrombocytopenia and made it possible to wait for oral anticoagulation to become efficient and platelet count to return to normal values without occurrence or recurrence of thromboembolism.     

Les thrombocytopénies induites par l’héparine : données récentes

Despite less frequent, heparin-induced thrombocytopenia (HIT) remains a severe complication of treatment with heparin, and is important to diagnose and manage appropriately. HIT results from an atypical immune response to heparin, with the synthesis of IgG antibodies specific to heparin-modified platelet factor 4 (PF4) which activate platelets, leukocytes and the endothelium. This activation explains that low platelet count is associated with thrombotic events in 50% of patients. The diagnosis of HIT is sometimes evoked because of atypical manifestations (i.e. cutaneous necrosis, amnesia, hypotension or dyspnea following intravenous injection of heparin). Biological assays are always necessary to confirm HIT in case of clinical suspicion, and specific rapid tests are now available for detecting anti-PF4 antibodies. However, their specificity is poor and functional assays such as serotonin release assay or platelet aggregation test are often necessary. Argatroban that is a direct antithrombin drug can be used in patients with severe renal failure and will be preferred to danaparoid sodium in this situation. Fondaparinux is not licensed for treating confirmed HIT and can only be used in case of suspicion. The early detection of HIT is based on the monitoring of platelet count recommended in surgical patients receiving a low molecular weight heparin and in all patients treated with unfractionated heparin.     

Heparin-induced thrombocytopenia in hemodialysis. Case report and review of the literature

Thrombocytopenia is a potential complication of heparin therapy. There are two forms of heparin-induced thrombocytopenia (HIT). Type-I HIT is characterized by a mild decrease in platelet count that occurs within the first 2-4 days after heparin initiation. The platelet count often returns to normal without stop heparin treatment. The mechanism of thrombocytopenia appears to be due to a direct effect of heparin on platelet activation. The second form (type-II) is an immune-mediated disorder characterized by severe thrombocytopenia, which may include both arterial and venous thrombosis. We present a case of type-II HIT occurred in a hemodialysis patient resulting in acute pulmonary embolism and peripheral venous thrombosis, and review the literature.     

Extensive skin necrosis induced by low-molecular-weight heparin in a patient with systemic lupus erythematosus and antiphospholipid syndrome

Low-molecular-weight heparin-induced skin necrosis can occur as a clinical feature of heparin-induced thrombocytopenia syndrome. Heparin-induced thrombocytopenia and antiphospholipid syndromes have some clinical features in common, including thrombocytopenia and thrombotic events. We describe a 46-year-old woman who developed extensive necrosis in the breast and other sites secondary to the use of enoxaparin after an elective hysterectomy. During the postoperative period, diagnoses of systemic lupus erythematosus and antiphospholipid syndrome were made because of some clinical and laboratory features (seizure, nephritis, bicytopenia, positive nuclear antibody, and positive antiphospholipid antibodies with a previous thrombotic event). The patient's clinical course improved only after corticosteroid therapy and the suspension of enoxaparin. Heparin-induced thrombocytopenia and antiphospholipid syndromes can have platelet factor 4 as a common denominator in their pathogenesis because platelet factor 4 tetramers can bind β2-glycoprotein molecules. This case suggests that use of low-molecular-weight heparins could be more risky in patients with an underlying immune disease and/or could trigger immune reactions that must be analyzed in larger studies.     

Bilateral lower extremity gangrene requiring amputation associated with heparin-induced thrombocytopenia: a case report

Heparin is a common cause of thrombocytopenia in hospitalized patients. Between 10% and 15% of patients receiving therapeutic doses of heparin develop thrombocytopenia. Heparin-induced thrombocytopenia (HIT) can cause severe bleeding and thrombosis owing to intravascular platelet aggregation. HIT must be distinguished from other causes of thrombocytopenia. Importantly, heparin use is often associated with an early fall in the platelet count that usually occurs within the first 4 days of initiation and recovers without cessation of heparin treatment. This nonimmune heparin-associated thrombocytopenia has not been found to be associated with thrombosis and does not necessitate discontinuation of heparin. The authors present a case report of a 70-year-old man who received heparin therapy following aortic tissue valve replacement and aortic root repair with graft and developed bilateral lower extremity arterial clots 6 days postoperatively in the setting of positive heparin antibody titers. Ultimately the patient required bilateral above-knee amputations.     

Venous thromboembolism in patients with hematologic malignancy and thrombocytopenia

The optimal management of hematologic malignancy‐associated venous thromboembolism (VTE) in patients with moderate‐to‐severe thrombocytopenia is unclear. This is a retrospective study of 128 adult patients with hematologic malignancies who were diagnosed with VTE. The outcome of patients with significant thrombocytopenia (≤50,000/µL) was compared with those without. Forty‐seven patients (36.7%) had a platelet count ≤50,000/µL during a period of time of perceived need for new or continued anticoagulation. The median nadir platelet count in those with significant thrombocytopenia was 10,000/µL (range 2,000–45,000/µL) versus 165,000/µL (50,000–429,000/µL) in those without (P < 0.001). The median duration of significant thrombocytopenia in the first group was 10 days (1–35 days). Therapy during the period of significant thrombocytopenia included prophylactic‐dose low‐molecular‐weight heparin ( LMWH) (47%), therapeutic‐dose LMWH or heparin (30%), warfarin (2%), inferior vena cava filter (2%), and observation (17%). Patients without thrombocytopenia were managed with the standard of care therapy. At a median follow‐up of more than 2 years, the risk of clinically significant bleeding (11% vs 6%, P = 0.22) including major bleeding (6% vs 2%) and clot progression or recurrence (21% vs 22%, P = 1.00) were similar in patients with or without significant thrombocytopenia. In a multivariate analysis, the risk of recurrence/progression (hazard ratio, HR 0.59, 95% CI 0.21–1.66, P = 0.31) and hemorrhage rate (HR 0.29, 95% CI 0.05–1.56, P = 0.15) did not differ based on the presence of significant thrombocytopenia. Within the limits of this retrospective study, cautious use of prophylactic‐dose LMWH may be safe in thrombocytopenic patients with hematologic malignancy‐associated VTE. Am. J. Hematol. 91:E468–E472, 2016. © 2016 Wiley Periodicals, Inc.     

Heparin-induced hyperkalemia

Heparin sodium is routinely used in the prophylaxis against deep venous thrombosis in medical and surgical patients. While most physicians are aware of heparin-induced thrombocytopenia and skin necrosis, the association of heparin and hyperkalemia is less well recognized. We present four cases in which the use of heparin was associated with hyperkalemia and discuss the pathophysiology. Our findings suggest that hyperkalemia can develop with the use of low-dose heparin, within seven days of initiating heparin therapy, and that patients with diabetes mellitus or chronic renal insufficiency are especially predisposed to this complication.     

Heparin-induced thrombocytopenia in pediatrics.

As in adult patients, heparin is used for prophylaxis and treatment of thromboembolism in newborns, children, and adolescents. Patients receiving heparin are potentially at risk to develop heparin-induced thrombocytopenia (HIT). HIT type II has been extensively described in the adult population; only a few reports address HIT type II in pediatric patients (total of 15 neonates, 4 young children, 12 older children and adolescents). The available data are discussed, and the case of a patient with recurrent thrombosis and HIT type II without thrombocytopenia is presented. The review of the literature reveals that HIT type II occurs especially in neonates and adolescents, corresponding to the two age peaks of thrombosis in pediatric patients. Risk factors for thrombosis include hereditary factors, immobilization, and surgery. HIT complications are severe and partly lead to life-threatening thromboembolism. In three patients, an increasing heparin demand was found. In five cases, thrombocytopenia was absent. Heparin was replaced mostly by danaparoid sodium; in three patients hirudin was used as an alternative anticoagulant. HIT type II represents a potentially dangerous complication of heparin therapy in pediatric patients and should be taken into consideration whenever heparin is given for prophylactic or therapeutic use in newborns, children, or adolescents.     

Heparin-induced thrombocytopenia

BACKGROUND AND OBJECTIVE: There are two types of heparin-induced thrombocytopenia (HIT). HIT I is characterized by a transitory, slight and asymptomatic reduction in platelet count, occurring in the first 1-2 days of therapy, that resolves spontaneously; in contrast, HIT II, which has an immunologic origin, is characterized by a significant thrombocytopenia generally after the fifth day of therapy that usually resolves in 5-15 days only after therapy withdrawal. HIT II is the most frequent and dangerous side-effect of heparin therapy; in fact, in spite of thrombocytopenia, it can be complicated by venous and arterial thrombosis. Therefore, the recognition of HIT II may be difficult due to the underlying thrombotic symptoms for which heparin is administered. The aim of this article is to review the most recent advances in the field and to give critical guidelines for the clinical diagnosis and treatment of HIT II. STATE OF THE ART: The prevalence of HIT II, as confirmed by laboratory tests, seems to be about 2% in patients receiving unfractionated heparin (UH), while it is much lower in those receiving low molecular weight heparin (LMWH). The immunologic etiology of HIT II is largely accepted. Platelet factor 4 (PF4) displaced from endothelial heparan sulphate or directly from the platelets, binds to the heparin molecule to form an immunogenic complex. The anti-heparin/ PF4 IgG immunocomplexes activate platelets and provoke an immunologic endothelial lesion with thrombocytopenia and/or thrombosis. The IgG anti-heparin/PF4 immunocomplex activates platelets mainly through binding with the FcgRIIa (CD32) receptor. The onset of thrombocytopenia is independent of the dosage, schedule and route of administration of heparin. Orthopedic and cardiovascular surgery patients receiving post-surgical prophylaxis or treatment for deep venous thrombosis are at higher risk of HIT II. Besides thrombocytopenia, cutaneous allergic manifestations and skin necrosis may be present. Hemorrhagic events are not frequent, while the major clinical complications in 30% of patients are both arterial and venous thromboses which carry a 20% mortality. The diagnosis of HIT II should be formulated on the basis of clinical criteria and in vitro demonstration of heparin-dependent antibodies. Functional tests, such as platelet aggregation and (14)C-serotonin release assay and immunologic tests, such as the search for anti-PF4/heparin complex antibodies by an ELISA method are available. If HITT II is probable, heparin must be immediately suspended and an alternative anticoagulant therapy should be initiated before resolution of thrombocytopenia and the following treatment with a vitamin K antagonist. The general opinion is to administer low molecular weight heparin (in the absence of in vitro cross-reactivity with the antibodies), heparinoids such as Orgaran or direct thrombin inhibitors such as hirudin. PERSPECTIVES: Further studies are required to elucidate the pathogenesis of HIT II and especially to discover the clinical and immunologic factors that induce the occurrence of thrombotic complications. The best therapeutic strategy remains to be confirmed in larger clinical trials.     

Warfarin-induced limb gangrene in the setting of lung adenocarcinoma

A 53-year-old man with lung adenocarcinoma developed pulmonary embolism and bilateral popliteal venous thrombosis. Treated with intravenous unfractionated heparin and discharged home on warfarin, he returned a week later with extending thrombosis. Treatment with heparin followed by warfarin was reinitiated. Twenty-four hours following the re-administration of warfarin, the patient's INR increased to 14.5. The platelet count dropped by more than 50%, and he developed venous limb gangrene of the left leg and skin necrosis of the right leg. Heparin-induced thrombocytopenia was ruled out, and coagulation studies showed a severe depletion of protein C as well as increased thrombin generation. The patient was transfused with fresh frozen plasma, and vitamin K was given. Heparin was continued, and after 4 weeks, the patient improved markedly showing only minimal necrosis of the toes. Venous limb gangrene is a major complication associated with warfarin therapy. Its pathogenesis is explained by a transient hypercoagulable state produced by protein C depletion that leads to microvascular thrombi progressing to venous limb gangrene. The present case emphasizes the importance of careful anticoagulation with heparin followed by slow initiation of low-dose warfarin, in order to minimize thrombotic complications.