Patients with quinine-induced immune thrombocytopenia have both "drug-dependent" and "drug-specific" antibodies

Spectroscopic Analysis of an Antimalarial Drug’s (Quinine) Influence on Human Serum Albumin Reduction and Antioxidant Potential

Quinine (Qi) is a well-known drug used in malaria therapy; it is also a potential anti-arrhythmic drug used in the treatment of calf cramps, rheumatoid arthritis, colds, and photodermatitis. Moreover, it is used in the food industry for the production of tonics. This study aimed to analyze the interaction between quinine and a transporting protein—human serum albumin (HSA)—as well as the influence of Qi on both protein reduction and antioxidant potential. It was found that Qi (via spectrofluorometric measurements and circular dichroism spectroscopy) binds to HSA with a low affinity and slightly affects the secondary structure of albumin. As demonstrated by the use of ABTS and FRAP assays, HSA has a higher antioxidant and reduction potential than Qi, while their mutual interaction results in a synergistic effect in antioxidant activity and reduction potential.

Case Report: First Case of Cefotaxime-Sulbactam-Induced Acute Intravascular Hemolysis in a Newborn With ABO Blood Type Incompatibility by the Mechanism of Non-Immunologic Protein Adsorption

Background

ABO blood type incompatibility hemolytic disease of newborn (ABO-HDN) and drug-induced immune hemolytic anemia (DIIHA) due to non-immunologic protein adsorption (NIPA) mainly cause extravascular hemolysis. All the reported severe DIIHA were caused by drug-induced antibodies, and rare report of acute intravascular hemolysis was caused by the NIPA mechanism or ABO-HDN.

Case presentation

We report the first case of acute intravascular hemolysis induced by cefotaxime sodium - sulbactam sodium (CTX - SBT) in a case of ABO-HDN which resulted in death at 55 h after birth. The mother’s blood type was O and RhD-positive, and the newborn’s blood type was B and RhD-positive. No irregular red blood cell (RBC) antibodies or drug-dependent antibodies related to CTX or SBT was detected in the mother’s plasma and the plasma or the RBC acid eluent of the newborn. Before the newborn received CTX - SBT treatment, the result of direct antiglobulin test (DAT) was negative while anti-B was positive (2 +) in both plasma and acid eluent. After the newborn received CTX - SBT treatment, the results of DAT for anti-IgG and anti-C3d were both positive, while anti-B was not detected in plasma, but stronger anti-B (3 +) was detected in acid eluent. In vitro experiments confirmed that NIPA of SBT promoted the specific binding of maternal-derived IgG anti-B to B antigen on RBCs of the newborn, thereby inducing acute intravascular hemolysis.

Conclusion

The NIPA effect of SBT promoted the specific binding of mother-derived IgG anti-B in newborn’s plasma to the newborn’s RBC B antigens and formed an immune complex, and then activated complement, which led to acute intravascular hemolysis. Drugs such as SBT with NIPA effect should not be used for newborns with HDN.

Spontaneous bleeding from orbital haemangioma in drug-induced thrombocytopaenia

An 81-year-old woman, a drug-induced thrombocytopaenia (DITP) patient, presented with a case of spontaneous bleeding from an orbital haemangioma manifesting as a sudden onset of ocular pain, proptosis and limited eye movement. Image studies revealed an extraconal, cystic lesion with haemorrhage. The ophthalmopathy was caused by the bleeding of the orbital haemangioma and it was resolved after embolisation of the feeding vessels. Spontaneous bleeding of orbital haemangioma is rare. This case emphasises that DITP may be the cause of spontaneous bleeding of orbital haemangioma by precipitating the inflammatory reactions within the tumour, which further cause the haemodynamic disturbances and ultimate spontaneous bleeding.

Drug-induced immune-mediated thrombocytopenia secondary to durvalumab use

Immunotherapy is an expanding area of cancer treatment with significant promise. Despite their efficacy, checkpoint inhibitors are associated with a number of immune-related adverse events; here, we described thrombocytopenia secondary todurvalumab.

Rifampicin-Induced Thrombocytopenia: A Case Report and Short Review of the Literature

Thrombocytopenia may be associated with a variety of conditions and risks depending on its severity, ranging from mild epistaxis to life-threating bleeding. Many drugs or herbal remedies can cause thrombocytopenia by either inhibiting platelet production and/or enhancing their destruction from the peripheral blood mediated via an immunological mechanism implicating drug-dependent antibodies. The latter entity is called drug-induced immune thrombocytopenia: a life-threatening, under-recognised condition, which is often a diagnostic challenge. Rifampicin is a widely used, well-tolerated, and effective bactericidal drug. Adverse events, except for gastrointestinal effects, headache, skin rash, and pruritus, are uncommon. The authors herein report on a patient with isolated thrombocytopenia with a recent medical history of brucellosis on rifampicin and doxycycline. Thrombocytopenia was proved to be rifampicin-induced. Also presented is a short review of the literature on this rare subject, which should be of great importance to clinicians.

Immune thrombocytopenia induced by beta-lactam antibiotics: Cross-reactions of responsible antibodies with other beta-lactam drugs

BACKGROUND

Beta-lactam antibiotics are a relatively common cause of immune thrombocytopenia. Because the many beta-lactam drugs now in clinical use have structural similarities, when a patient experiences this complication the question of whether an alternative member of this drug family can safely be used often arises but there are little data available to guide this decision.

STUDY DESIGN AND METHODS

Drug-dependent, platelet-reactive antibodies from 32 patients who experienced thrombocytopenia while being treated with a beta-lactam drug of the penam (piperacillin, etc.) or cephem (ceftriaxone etc.) groups were studied for serologic cross-reactivity with other drugs from these families using flow cytometry. Cross-reactions observed were analyzed for correlations with structural features of the drugs tested.

RESULTS

Among 14 antibodies specific for penam drugs, five "strong" cross-reactions with other penam drugs were found. Among 18 antibodies specific for cephem drugs, 8 "strong cross-reactions were identified. Antibodies induced by penam drugs did not cross-react strongly with cephem drugs and vice versa. A strong correlation between cross-reactions and similar or identical R1 side groups of the beta-lactams studied was observed.

DISCUSSION

The findings suggest that patients who experience immune thrombocytopenia while being treated with a beta-lactam of the penam group can safely be treated with a cephem drug and vice versa. If a patient is to be switched to another beta lactam within the same group, the likelihood of serologic cross-reactivity can be minimized by choosing an agent with a distinctly different R1 side group.

Platelet transfusion refractoriness: how do I diagnose and manage?

Platelet refractoriness continues to be a problem for thrombocytopenic patients because the risk of a major spontaneous or life-threatening bleed significantly increases when platelet counts drop below 10 × 109/L. The majority of patients have nonimmune causes driving the refractoriness, such as bleeding, medications, or diffuse intravascular coagulation; however, this article is dedicated to the diagnosis and support of patients with immune-based platelet refractoriness. Antibodies to class I HLA molecules (A and B alleles) are responsible for most immune-based refractory cases, with antibodies to platelet antigens seen much less frequently. Patients may be supported with either crossmatch-compatible or HLA-matched/compatible platelet units. When trying to select HLA units it can be difficult to find a perfect "4 of 4" match for the patient's class IA and IB alleles. In these cases, it is better to use the antibody specificity prediction method, which identifies compatible units that lack antigens recognized by the patient's anti-HLA antibodies. For an algorithmic approach to the patient with platelet refractoriness, see Visual Abstract.

Plexus Slim®-Induced Immune Thrombocytopenic Purpura

Primary immune thrombocytopenic purpura (ITP) is a common cause of thrombocytopenia. Due to the many possible precipitating factors, the diagnostic approach can be complex in nature. Much of the published literature on drug-induced ITP (DITP) report on quinine-induced thrombocytopenia. Here we present a case of the proposed dietary cause of DITP by the weight loss supplement Plexus® which contains two potential thrombocytopenia-causing compounds, garcinia cambogia fruit extract, and chromium polynicotinate. This case highlights how a thorough patient history, including evaluation of supplement use and dietary habits, can be of the utmost importance in the workup of ITP.

Immune thrombocytopenic purpura caused by the over-the-counter weight supplement Root of Tejocote (Crataegus species)

Over-the-counter supplements, such as Alipotec which often purported to amplify weight loss and readily available in naturopathic shops, can have clinically significant patient outcomes including severe cytopenia, and even inducing immune thrombocytopenic purpura.

Drug-induced activation of integrin alpha IIb beta 3 leads to minor localized structural changes

Integrins are transmembrane proteins involved in hemostasis, wound healing, immunity and cancer. In response to intracellular signals and ligand binding, integrins adopt different conformations: the bent (resting) form; the intermediate extended form; and the ligand-occupied active form. An integrin undergoing such conformational dynamics is the heterodimeric platelet receptor αIIbβ3. Although the dramatic rearrangement of the overall structure of αIIbβ3 during the activation process is potentially related to changes in the protein secondary structure, this has not been investigated so far in a membrane environment. Here we examine the Mn2+- and drug-induced activation of αIIbβ3 and the impact on the structure of this protein reconstituted into liposomes. By quartz crystal microbalance with dissipation monitoring and activation assays we show that Mn2+ induces binding of the conformation-specific antibody PAC-1, which only recognizes the extended, active integrin. Circular dichroism spectroscopy reveals, however, that Mn2+-treatment does not induce major secondary structural changes of αIIbβ3. Similarly, we found that treatment with clinically relevant drugs (e.g. quinine) led to the activation of αIIbβ3 without significant changes in protein secondary structure. Molecular dynamics simulation studies revealed minor local changes in the beta-sheet probability of several extracellular domains of the integrin. Our experimental setup represents a new approach to study transmembrane proteins, especially integrins, in a membrane environment and opens a new way for testing drug binding to integrins under clinically relevant conditions.

Acquired Glanzmann thrombasthenia: From antibodies to anti-platelet drugs

In contrast to the inherited platelet disorder given by mutations in the ITGA2B and ITGB3 genes, mucocutaneous bleeding from a spontaneous inhibition of normally expressed αIIbβ3 characterizes acquired Glanzmann thrombasthenia (GT). Classically, it is associated with autoantibodies or paraproteins that block platelet aggregation without causing a fall in platelet count. However, inhibitory antibodies to αIIbβ3 are widely associated with primary immune thrombocytopenia (ITP), occur in secondary ITP associated with leukemia and related disorders, solid cancers and myeloma, other autoimmune diseases, following organ transplantation while cytoplasmic dysregulation of αIIbβ3 function features in myeloproliferative and myelodysplastic syndromes. Antibodies to αIIbβ3 occur during viral and bacterial infections, while drug-dependent antibodies reacting with αIIbβ3 are a special case. Direct induction of acquired GT is a feature of therapies that block platelets in coronary artery disease. This review looks at these conditions, emphasizing molecular mechanisms, therapy, patient management and future directions for research.

A Case of Hyperacute Severe Thrombocytopenia Occurring Less than 24 Hours after Intravenous Tirofiban Infusion

Thrombocytopenia is defined as a condition where the platelet count is below the lower limit of normal (<150 G/L), and it is categorized as mild (100–149 G/L), moderate (50–99 G/L), and severe (<50 G/L). We present here a 79-year-old man who developed severe thrombocytopenia with a platelet count of 6 G/L, less than 24 hours after intravenous tirofiban infusion that was given to the patient during a percutaneous transluminal coronary angioplasty procedure with placement of 3 drug-eluting stents. The patient's baseline platelet count was 233 G/L before the procedure. Based on the timeline of events during hospitalization and laboratory evidence, it was highly likely that the patient's thrombocytopenia was the result of tirofiban-induced immune thrombocytopenia, a type of drug-induced immune thrombocytopenia (DITP) which occurs due to drug-dependent antibody-mediated platelet destruction. Anticoagulant-mediated artefactual pseudothrombocytopenia was ruled out as no platelet clumping was seen on the peripheral blood smears. The treatment of DITP includes discontinuation of the causative drug; monitoring of platelet count recovery; or treatment of severe thrombocytopenia with glucocorticoids, IVIG, or platelet transfusions depending on the clinical presentation. The most likely causative agent of this patient's thrombocytopenia—tirofiban—was discontinued, and the patient did not develop any signs of bleeding during the remainder of his hospital stay. His platelet count gradually improved to 24 G/L, and he was discharged on the sixth hospital day.

A Case Report of Nephrotic Syndrome While Undergoing Quinine Therapy

We summarize the case of an 81-year-old Caucasian female who presented to her family physician with signs and symptoms of nephrotic syndrome following a brief exposure to quinine. Prior to that visit, she was clinically well with no chronic medical ailments and met with her family physician for annual physical assessments. She had taken 11 tablets of quinine for nocturnal leg cramps over the course of 28 days before starting to notice mild peripheral edema, which subsequently progressed, leading to a family physician review. Her initial serum albumin level was 12 g/L, and a 24-hour urine protein output was quantified at 8.14 g/day; she was diagnosed as having nephrotic syndrome. A kidney biopsy confirmed the diagnosis of minimal change disease (MCD). Quinine therapy was stopped, and she was initiated on a tapering regime of prednisone with concurrent cyclosporine therapy. Within a fortnight of starting therapy, she went into remission and her immunosuppressive medications were rapidly tapered and discontinued. This paper reports an association between the use of quinine and subsequent MCD. This case report proposes that the use of quinine has an association with, and may be causal for, the development of minimal change disease. As this is yet an unreported adverse effect, this paper seeks to increase the knowledge of the varied and numerous effects of quinine.  

Drug-induced immune thrombocytopenia: Mapping of the drug binding site to the membrane-proximal region of platelet GPIX

Drug-induced Immune thrombocytopenia (DIT) is a common complication of several medications, including commonly used antibiotics. The most widely studied DIT is caused by quinine. In DIT, antibodies predominantly bind to the platelet membrane glycoprotein (GP) IX in a drug-dependent fashion resulting in increased platelet clearance. Binding of the sensitizing drug, such as quinine, to GPIX has been proposed but is yet to be established. This work demonstrates that quinine is retained specifically by human GPIX. Quinine binding was first analyzed in wild-type mouse platelets and in transgenic mouse platelet expressing human GPIX using high performance liquid chromatography. Binding of quinine to GPIX was then measured in Chinese hamster ovary (CHO) cells expressing a combination of wild type, human or mouse, three human/mouse chimeric constructs and six mutant GPIX proteins. Quinine was retained by human GPIX. No detectable absorption was observed with mouse GPIX or human GPIbα. The quinine binding site was mapped to residues 110-115 of human GPIX suggesting that quinine interacts with specific residues of the GP. These findings provide further insights into the molecular mechanisms of DIT.

Metronidazole caused profound drug-induced immune thrombocytopenia

Metronidazole is commonly prescribed and has not been known to cause drug‐induced immune thrombocytopenia. We have provided clinical and laboratory evidence with DDabs that metronidazole can cause drug‐induced immune thrombocytopenia (DITP). Providers must be aware of metronidazole causing DITP because recognition of thrombocytopenia is critical and cessation of the drug should occur promptly.

Vancomycin-Induced Thrombocytopenia: A Narrative Review

Thrombocytopenia has been reported as an adverse reaction of numerous drugs. Vancomycin is often overlooked as a culprit but has been associated with several cases of thrombocytopenia that were not well described in the literature. A literature search was conducted to find reports of thrombocytopenia induced by vancomycin. Biomedical databases including 'PubMed', 'Scopus', and 'Web of Science' were searched using terms 'vancomycin', 'platelet', 'pancytopenia', 'thrombocytopenia', and 'bleeding'. English language articles published before July 2015 were included. Thirty-nine papers including 29 case reports (30 cases), five observational studies, two clinical trials, two letters, and one case series remained for final analysis. The main route of administration was intravenous infusion. This adverse reaction seems to be duration dependent with the mean time to platelet nadir count of 8 days in reported cases. The interval may be significantly shorter in re-exposure to the drug. Platelet nadir counts ranged from 2000 to 100,000/mL in patients who experienced bleeding. Vancomycin-specific antibodies were detected in 13 of 17 patients who were tested in the case reports. Based on the Naranjo Adverse Drug Reaction Probability Scale, reaction was 'definite', 'probable', and 'possible' in 1, 15, and 14 patients, respectively. Among 30 cases, vancomycin was discontinued in 29 patients and platelets returned to normal counts within 5-6 days in 17 of them; in one patient, vancomycin was not discontinued, but platelet count recovered 11 days after the nadir time. Transfusion might be recommended if severe thrombocytopenia and bleeding occurs. Intravenous immunoglobulins, corticosteroids, rituximab, and plasma exchange should be reserved for patients with resistant thrombocytopenia and severe bleeding as mentioned in a number of reports.

Thrombotic microangiopathy associated with Valproic acid toxicity

Background

Thrombotic microangiopathy (TMA) is a serious, sometimes life-threatening disorder marked by the presence of endothelial injury and microvascular thrombi. Drug-induced thrombotic microangiopathy (DI-TMA) is one specific TMA syndrome that occurs following drug exposure via drug-dependent antibodies or direct tissue toxicity. Common examples include calcineurin inhibitors Tacrolimus and Cyclosporine and antineoplastics Gemcitabine and Mitomycin. Valproic acid has not been implicated in DI-TMA. We present the first case of a patient meeting clinical criteria for DI-TMA following admission for valproic acid toxicity.

Case presentation

An adolescent male with difficult to control epilepsy was admitted for impaired hepatic function while on valproic acid therapy. On the third hospital day, he developed severe metabolic lactic acidosis and multiorgan failure, prompting transfer to the pediatric intensive care unit. Progressive anemia and thrombocytopenia instigated an evaluation for thrombotic microangiopathy, where confirmed by concomitant hemolysis, elevated lactate dehydrogenase (LDH), low haptoglobin, and concurrent oliguric acute kidney injury. Thrombotic thrombocytopenic purpura was less likely with adequate ADAMTS13. Discontinuing valproic acid reversed the anemia, thrombocytopenia, and normalized the LDH and haptoglobin, supporting a drug-induced cause for the TMA.

Conclusion

To the best of our knowledge, this is the first report of drug-induced TMA from valproic acid toxicity.

New-onset acute thrombocytopenia in hospitalized patients: pathophysiology and diagnostic approach

Thrombocytopenia is a hematological finding commonly encountered in daily clinical practice from asymptomatic clinic patients to critically ill intensive care unit patients. A broad spectrum of etiologies and variation in clinical presentation often present a diagnostic challenge. Furthermore, concomitant presence of thrombosis and thrombocytopenia, as in cases of thrombotic thrombocytopenia, complicates the management. In hospitalized patients, new-onset thrombocytopenia is an important reason for hematology consultation. Therefore, it is of utmost importance that the etiology is diagnosed accurately. In addition, a basic understanding of the pathophysiology and the differential diagnosis avoids delay in the diagnosis and leads to rapid initiation of treatment. This review will address causes of thrombocytopenia that arises in hospitalized patients with an emphasis on the pathophysiological basis of each disorder.

Effect of quinine and artesunate combination therapy on platelet count of children with severe malaria

BACKGROUND

There are several case reports of quinine-induced thrombocytopenia but no clinical trials to ascertain its incidence and significance in severe malaria.

OBJECTIVES

The primary objective was to assess the effect of quinine on the platelet count in children with severe malaria and to compare it with artesunate combination therapy (ACT), and the secondary objective was to assess outcome of treatment with quinine and ACT.

METHODS

An open-labelled, randomised, controlled trial was undertaken in 100 children aged 6 months to 12 years who were diagnosed with malaria by microscopy and/or rapid diagnostic test kits with at least one WHO clinical or laboratory criterion for severe malaria. All subjects were commenced on either quinine or ACT. Clindamycin was added to artesunate as a combination drug (ACT). It was also given to patients on quinine to avoid its confounding effect on the results. Platelet counts were undertaken every 24 hours for 7 consecutive days, temperature and coma score (Blantyre coma score ≥3 in children <4 years or Glasgow coma score ≥13 in children >4 years) was recorded 6-hourly and peripheral smears were taken 12-hourly until two consecutively negative smears were obtained. The primary outcome was a fall in the platelet count by ≥20% from the time of drug initiation until day 7. The secondary outcome was comparison of the efficacy, parasite clearance time, fever clearance time, coma recovery time and adverse effects of quinine vs ACT.

RESULTS

30.4% patients in the quinine group (n = 48) had ≥20% fall in platelet count and 10.8% of patients in the ACT group (n = 46) (P = 0.02). Despite the fall in platelet count, there was no bleeding. The efficacy of ACT was significantly better than quinine but the other treatment outcomes showed insignificant difference.

CONCLUSION

Quinine should be used with caution in patients with severe malaria because of the potential risk of quinine-induced thrombocytopenia.

Levofloxacin-Induced Acute Immune-Mediated Thrombocytopenia of Rapid-Onset

Drug-induced immune thrombocytopenia (D-ITP) typically occurs after the patient has been receiving the implicated drug for at least 1 week, due to newly forming drug-dependent antibodies ("typical-onset" D-ITP). A "rapid-onset" form of D-ITP can occur when previous sensitization has occurred, where antibodies have thus already been formed, and a precipitous platelet count fall occurs upon reexposure. Typical-onset D-ITP has been reported after levofloxacin, but the rapid-onset form with a well-documented previous exposure has not been described. We report a 76-year-old male treated with levofloxacin for acute exacerbation of chronic obstructive pulmonary disease. After a single 750 mg oral dose of levofloxacin, his platelet count fell from 187 to 5 × 10⁹/L (nadir) over 4 days. Other causes of thrombocytopenia were ruled out. He had received a previous course of levofloxacin 6 months earlier. Discontinuation of levofloxacin and treatment with intravenous immunoglobulin and dexamethasone resulted in platelet count recovery. Levofloxacin-dependent antibodies were not detectable, consistent with the known low sensitivity of laboratory tests for drug-dependent antibodies, presumably indicating antibodies against levofloxacin metabolites, as is indirectly supported by the abrupt but relatively slow platelet count decline observed. This case illustrates a rapid-onset presentation of levofloxacin-induced D-ITP in the setting of previous drug exposure.

A rare case report of acyclovir-induced immune thrombocytopenia with tongue hematomas as the first sign, and a literature review

Background

Acyclovir has been widely used to treat infections caused by herpes simplex virus (HSV) and varicella zoster virus (VZV). The common adverse effects of this drug include nausea, diarrhea, headache, dizziness and mental changes. The immune thrombocytopenia induced by acyclovir is rare.

Case presentation

A 67-year-old Chinese male who was given acyclovir 5 mg kg⁻¹ 8 hourly intravenously for treatment of VZV infection developed severe thrombocytopenia with fist sign in oral cavity within 10 days of starting using acyclovir. The patient’s condition was improved by stopping using acyclovir and further supportive treatment. The acyclovir-dependent platelet antibody test showed positive results, which implicated acyclovir as the causative agent. The final definitive diagnosis of acyclovir-induced immune thrombocytopenia was established basing on the time correlation between the start of using acyclovir and the onset of symptoms of thrombocytopenia, combining with excluding of other common causes of thrombocytopenia.

Conclusion

There have been few reports of acyclovir-induced immune thrombocytopenia. This is the first case report and literature review of acyclovir-induced immune thrombocytopenia, with tongue hematoma as the first sign. Dentists should never overlook this rare adverse effect of acyclovir, as a rapid and appropriate treatment may prevent further severe life-threatening complications.

Diversity and severity of adverse reactions to quinine: A systematic review

Quinine is a common cause of drug-induced thrombocytopenia and the most common cause of drug-induced thrombotic microangiopathy. Other quinine-induced systemic disorders have been described. To understand the complete clinical spectrum of adverse reactions to quinine we searched 11 databases for articles that provided sufficient data to allow evaluation of levels of evidence supporting a causal association with quinine. Three reviewers independently determined the levels of evidence, including both immune-mediated and toxic adverse reactions. The principal focus of this review was on acute, immune-mediated reactions. The source of quinine exposure, the involved organ systems, the severity of the adverse reactions, and patient outcomes were documented. One hundred-fourteen articles described 142 patients with definite or probable evidence for a causal association of quinine with acute, immune-mediated reactions. These reactions included chills, fever, hypotension, painful acral cyanosis, disseminated intravascular coagulation, hemolytic anemia, thrombocytopenia, neutropenia, acute kidney injury, rhabdomyolysis, liver toxicity, cardiac ischemia, respiratory failure, hypoglycemia, blindness, and toxic epidermal necrolysis. One hundred-two (72%) reactions were caused by quinine pills; 28 (20%) by quinine-containing beverages; 12 (8%) by five other types of exposures. Excluding 41 patients who had only dermatologic reactions, 92 (91%) of 101 patients had required hospitalization for severe illness; 30 required renal replacement therapy; three died. Quinine, even with only minute exposure from common beverages, can cause severe adverse reactions involving multiple organ systems. In patients with acute, multi-system disorders of unknown origin, an adverse reaction to quinine should be considered.

Probable Levofloxacin-Induced Thrombocytopenia in a Patient Previously on Ciprofloxacin: A Case Report and Literature Review

Drug-induced thrombocytopenia is a poorly understood, yet common phenomenon widely encountered in clinical practice. We present a case of suspected levofloxacin-induced thrombocytopenia, a rare side effect of a ubiquitous antibiotic, in a patient without similar effect to ciprofloxacin. This report builds upon other isolated case reports of fluoroquinolone-induced thrombocytopenia and demonstrates our algorithmic approach to the issue as well as a literature review pertaining to fluoroquinolone-induced thrombocytopenia.

Effect of anti-tuberculosis drugs on hematological profiles of tuberculosis patients attending at University of Gondar Hospital, Northwest Ethiopia

BACKGROUND

Tuberculosis (TB) treatment may present significant hematological disorder and some anti-TB drugs also have serious side effects. Although many other diseases may be reflected by the blood and its constituents, the abnormalities of red cells, white cells, platelets, and clotting factors are considered to be primary hematologic disorder as a result of tuberculosis treatment. The aim of this study was to determine hematological profiles of TB patients before and after intensive phase treatment.

OBJECTIVE

The aim of this study was to determine hematological profiles of TB patients before and after intensive phase treatment.

METHODS

Smear positive new TB patients were recruited successively and socio-demographic characteristics were collected using pre-tested questionnaire. About 5 ml of venous blood was collected from each patient and the hematological profiles were determined using Mindry BC 3000 plus automated hematology analyzer.

RESULT

The hematological profiles of TB patients showed statistically significant difference in hematocrit (38.5 % versus 35.7 %), hemoglobin (12.7 g/lversus11.8 g/l) and platelet (268 × 10(3)/μlversus239 × 10(3)/μl) values of patients before initiation of treatment and after completion of the intensive phase of tuberculosis treatment, respectively (P < 0.05). The red cell distribution width (RDW) of treatment naïve TB patients was by far lower (17.6 ± 7.09 %) than the corresponding RDW (31.9 ± 5.19 %) of intensive phase treatment completed patients. Among TB patients that had high platelet distribution width (PDW) (n = 11) before initiation of TB treatment, 10 demonstrated lower PDW values after completion of the intensive phase. There was no significant difference on total white blood cell count among TB patients before and after completion of the 2 month treatment.

CONCLUSION

The levels of hemoglobin, hematocrit and platelet count of the TB patients were significantly lowered after completion of the intensive phase of TB treatment. Significant variation of the RDW and PDW were also observed among treatment naïve and treatment completed patients. Hematological abnormalities resulted from TB treatment should be assessed continuously throughout the course of tuberculosis therapy.

Mechanism of quinine-dependent monoclonal antibody binding to platelet glycoprotein IIb/IIIa

Drug-dependent antibodies (DDAbs) that cause acute thrombocytopenia upon drug exposure are nonreactive in the absence of the drug but bind tightly to a platelet membrane glycoprotein, usually α(IIb)/β3 integrin (GPIIb/IIIa) when the drug is present. How a drug promotes binding of antibody to its target is unknown and is difficult to study with human DDAbs, which are poly-specific and in limited supply. We addressed this question using quinine-dependent murine monoclonal antibodies (mAbs), which, in vitro and in vivo, closely mimic antibodies that cause thrombocytopenia in patients sensitive to quinine. Using surface plasmon resonance (SPR) analysis, we found that quinine binds with very high affinity (K(D) ≈ 10⁻⁹ mol/L) to these mAbs at a molar ratio of ≈ 2:1 but does not bind detectably to an irrelevant mAb. Also using SPR analysis, GPIIb/IIIa was found to bind monovalently to immobilized mAb with low affinity in the absence of quinine and with fivefold greater affinity (K(D) ≈ 2.2 × 10⁻⁶) when quinine was present. Measurements of quinine-dependent binding of intact mAb and fragment antigen-binding (Fab) fragments to platelets showed that affinity is increased 10 000- to 100 000-fold by bivalent interaction between antibody and its target. Together, the findings indicate that the first step in drug-dependent binding of a DDAb is the interaction of the drug with antibody, rather than with antigen, as has been widely thought, where it induces structural changes that enhance the affinity/specificity of antibody for its target epitope. Bivalent binding may be essential for a DDAb to cause thrombocytopenia.

Structural basis for quinine-dependent antibody binding to platelet integrin αIIbβ3

Drug-induced immune thrombocytopenia (DITP) is caused by antibodies that react with specific platelet-membrane glycoproteins when the provoking drug is present. More than 100 drugs have been implicated as triggers for this condition, quinine being one of the most common. The cause of DITP in most cases appears to be a drug-induced antibody that binds to a platelet membrane glycoprotein only when the drug is present. How a soluble drug promotes binding of an otherwise nonreactive immunoglobulin to its target, leading to platelet destruction, is uncertain, in part because of the difficulties of working with polyclonal human antibodies usually available only in small quantities. Recently, quinine-dependent murine monoclonal antibodies were developed that recognize a defined epitope on the β-propeller domain of the platelet integrin αIIb subunit (GPIIb) only when the drug is present and closely mimic the behavior of antibodies found in human patients with quinine-induced thrombocytopenia in vitro and in vivo. Here, we demonstrate specific, high-affinity binding of quinine to the complementarity-determining regions (CDRs) of these antibodies and define in crystal structures the changes induced in the CDR by this interaction. Because no detectable binding of quinine to the target integrin could be demonstrated in previous studies, the findings indicate that a hybrid paratope consisting of quinine and reconfigured antibody CDR plays a critical role in recognition of its target epitope by an antibody and suggest that, in this type of drug-induced immunologic injury, the primary reaction involves binding of the drug to antibody CDRs, causing it to acquire specificity for a site on a platelet integrin.

Immune thrombocytopenia associated with consumption of tonic water

Thrombocytopenic purpura can develop from an induced antibody response that destroys platelets. Megakaryocyte production may also play a role. Although the inciting antigen is usually not identified, it is important to consider medications. This article presents the case of a man who developed sudden onset of severe thrombocytopenia associated with the ingestion of quinine-containing tonic water.

Fatal quinine-induced thrombocytopenia from pulmonary haemorrhage

Severe drug-induced thrombocytopenia is a well known but rare complication of quinine. This paper presents a discussion on quinine-induced thrombocytopenia based on a patient who developed fatal thrombocytopenia and pulmonary haemorrhage.

Hospital-acquired thrombocytopenia

The development of thrombocytopenia is common in hospitalized patients and is associated with increased mortality. Frequent and important causes of thrombocytopenia in hospitalized patients include etiologies related to the underlying illness for which the patient is admitted, such as infection and disseminated intravascular coagulation, and iatrogenic etiologies such as drug-induced immune thrombocytopenia, heparin-induced thrombocytopenia, posttransfusion purpura, hemodilution, major surgery, and extracorporeal circuitry. This review presents a brief discussion of the pathophysiology, distinguishing clinical features, and management of these etiologies, and provides a diagnostic approach to hospital-acquired thrombocytopenia that considers the timing and severity of the platelet count fall, the presence of hemorrhage or thrombosis, the clinical context, and the peripheral blood smear. This approach may offer guidance to clinicians in distinguishing among the various causes of hospital-acquired thrombocytopenia and providing management appropriate to the etiology.

Syndromes of thrombotic microangiopathy

This review article covers the diverse pathophysiological pathways that can lead to microangiopathic hemolytic anemia and a procoagulant state with or without damage to the kidneys and other organs.

Antiplatelet antibodies in oxaliplatin-induced immune thrombocytopenia

Drug-induced immune thrombocytopenia may be potentially fatal; here we report the development of severe thrombocytopenia with strong oxaliplatin-dependent antiplatelet antibodies.

Diagnosis and classification of drug-induced autoimmunity (DIA)

Since sulfadiazine associated lupus-like symptoms were first described in 1945, certain drugs have been reported to interfere with the immune system and induce a series of autoimmune diseases (named drug-induced autoimmunity, DIA), exemplified by systemic lupus erythematosus (SLE). Among the drugs, procainamide and hydralazine are considered to be associated with the highest risk for developing lupus, while quinidine has a moderate risk, and all other drugs have low or very low risk. More recently, drug-induced lupus has been associated with the use of newer biological modulators, such as tumor necrosis factor (TNF)-alpha inhibitors and cytokines. In addition to lupus, other major autoimmune diseases, including vasculitis and arthritis, have also been associated with drugs. Because resolution of symptoms generally occurs after cessation of the offending drugs, early diagnosis is crucial for treatment strategy and improvement of prognosis. Unfortunately, it is difficult to establish standardized criteria for DIA diagnosis. Diagnosis of DIA requires identification of a temporal relationship between drug administration and the onset of symptoms, but the relative risk with respect to dose and duration for each drug has rarely been determined. DIA is affected by multiple genetic and environmental factors, leading to difficulties in establishing a list of global clinical features that are characteristic of most or all DIA patients. Moreover, the distinction between authentic DIA and unmasking of a latent autoimmune disease also poses challenges. In this review, we summarize the highly variable clinical features and laboratory findings of DIA, with an emphasis on the diagnostic criteria.

Drug-induced immune thrombocytopenia: incidence, clinical features, laboratory testing, and pathogenic mechanisms

Drug-induced immune thrombocytopenia (DIIT) is a relatively uncommon adverse reaction caused by drug-dependent antibodies (DDAbs) that react with platelet membrane glycoproteins only when the implicated drug is present. Although more than 100 drugs have been associated with causing DIIT, recent reviews of available data show that carbamazepine, eptifibatide, ibuprofen, quinidine, quinine, oxaliplatin, rifampin, sulfamethoxazole, trimethoprim, and vancomycin are probably the most frequently implicated. Patients with DIIT typically present with petechiae, bruising, and epistaxis caused by an acute, severe drop in platelet count (often to <20,000 platelets/pL). Diagnosis of DIIT is complicated by its similarity to other non-drug-induced immune thrombocytopenias, including autoimmune thrombocytopenia, posttransfusion purpura, and platelet transfusion refractoriness, and must be differentiated by temporal association of exposure to a candidate drug with an acute, severe drop in platelet count. Treatment consists of immediate withdrawal of the implicated drug. Criteria for strong evidence of DIIT include (1) exposure to candidate drug-preceded thrombocytopenia; (2) sustained normal platelet levels after discontinuing candidate drug; (3) candidate drug was only drug used before onset of thrombocytopenia or other drugs were continued or reintroduced after resolution of thrombocytopenia, and other causes for thrombocytopenia were excluded; and (4) reexposure to the candidate drug resulted in recurrent thrombocytopenia. Flow cytometry testing for DDAbs can be useful in confirmation of a clinical diagnosis, and monoclonal antibody enzyme-linked immunosorbent assay testing can be used to determine the platelet glycoprotein target(s), usually GPIIb/IIIa or GPIb/IX/V, but testing is not widely available. Several pathogenic mechanisms for DIIT have been proposed, including hapten, autoantibody, neoepitope, drug-specific, and quinine-type drug mechanisms. A recent proposal suggests weakly reactive platelet autoantibodies that develop greatly increased affinity for platelet glycoprotein epitopes through bridging interactions facilitated by the drug is a possible mechanism for the formation and reactivity of quinine- type drug antibodies.

Drug-induced immune thrombocytopenia

Thrombocytopenia is caused by immune reactions elicited by diverse drugs in clinical practice. The activity of the drug-dependent antibodies produces a marked decrease in blood platelets and a risk of serious bleeding. Understanding of the cellular mechanisms that drive drug-induced thrombocytopenia has advanced recently but there is still a need for improved laboratory tests and treatment options. This article provides an overview of the different types of drug-induced thrombocytopenia, discusses potential pathologic mechanisms, and considers diagnostic methods and treatment options.

A systematic evaluation of laboratory testing for drug-induced immune thrombocytopenia

BACKGROUND

Drug-induced immune thrombocytopenia (DITP) can be confirmed by the demonstration of drug-dependent platelet antibodies in vitro; however, laboratory testing is not readily accessible and test methods are not standardized.

OBJECTIVE

To identify drugs with the strongest evidence for causing DITP based on clinical and laboratory criteria.

PATIENTS/METHODS

We developed a grading system to evaluate the quality of DITP laboratory testing. The 'DITP criteria' were: (i) Drug (or metabolite) was required for the reaction in vitro; (ii) Immunoglobulin binding was demonstrated; (iii) Two or more laboratories obtained positive results; and (iv) Platelets were the target of immunoglobulin binding. Laboratory diagnosis of DITP was considered definite when all criteria were met and probable when positive results were reported by only one laboratory. Two authors applied the DITP criteria to published reports of each drug identified by systematic review. Discrepancies were independently adjudicated.

RESULTS

Of 153 drugs that were clinically implicated in thrombocytopenic reactions, 72 (47%) were associated with positive laboratory testing. Of those, 16 drugs met criteria for a definite laboratory diagnosis of DITP and thus had the highest probability of causing DITP. Definite drugs were: quinine, quinidine, trimethoprim/sulfamethoxazole, vancomycin, penicillin, rifampin, carbamazepine, ceftriaxone, ibuprofen, mirtazapine, oxaliplatin and suramin; the glycoprotein IIbIIIa inhibitors abciximab, tirofiban and eptifibatide; and heparin.

CONCLUSIONS

We identified drugs with the strongest evidence for an association with immune thrombocytopenia. This list may be helpful for ranking potential causes of thrombocytopenia in a given patient.

Vancomycin-induced thrombocytopenia without isolation of a drug-dependent antibody

Vancomycin is a glycopeptide antibiotic used in the treatment of gram-positive infections including methicillin-resistant Staphylococcus aureus (MRSA). The most common adverse reaction to vancomycin is red man syndrome, which is a histaminergic reaction causing a rash on the upper torso, neck, and face after rapid infusion of the drug. Less commonly, vancomycin has been associated with thrombocytopenia. The etiology is believed to be the induction of drug-dependent antibodies, which in turn cause immune-mediated destruction of platelets. We describe a 41-year-old man who received two courses of vancomycin for the treatment of MRSA pneumonia and then experienced a decline in platelet count to a nadir of 15 x 10³/mm³. Vancomycin was discontinued, doxycycline was started, and the patient's platelet count rebounded over the next 6 days. The patient was readmitted to the hospital 2 months later for MRSA bacteremia and was rechallenged with vancomycin. He again experienced a decline in platelet count. Vancomycin was discontinued, and daptomycin was started. The patient's platelet count rebounded to normal levels over the next 5 days. Although the patient experienced acute thrombocytopenia after vancomycin exposure, no bleeding complications occurred, and the patient's platelet count rebounded to normal after the discontinuation of vancomycin. The patient had no other known risk factors for the development of rapid thrombocytopenia. Use of the Naranjo adverse drug reaction probability scale indicated a definite relationship (score of 9) between the patient's development of thrombocytopenia and vancomycin therapy. Although vancomycin was the presumed cause of thrombocytopenia in this patient, no drug-dependent antibody was isolated from blood samples collected after both exposures to vancomycin (analyzed by using a screening assay to identify drug-dependent antibodies to vancomycin [developed by the BloodCenter of Wisconsin]). Although the evidence supporting vancomycin induction of antibody-mediated destruction of platelets was lacking, further studies delineating alternate mechanisms of platelet destruction are warranted. Therefore, even in the absence of a positive antibody test, vancomycin should still be considered in the differential diagnosis as a cause of drug-induced thrombocytopenia.

A case of daptomycin-induced immune thrombocytopenia

We report a case of severe daptomycin-induced immune thrombocytopenia in a patient treated for methicillin-resistant Staphylococcus epidermidis and ampicillin-resistant Enterococcus faecalis bacteremia acquired in an intensive care unit. Serum antibodies bound to platelets in the presence of daptomycin on flow cytometry. There was no evidence of other causes of thrombocytopenia. The patient died of brain herniation complicating extensive cerebral hemorrhage. To our knowledge, this is the first described case of daptomycin-induced thrombocytopenia.

Moxifloxacin (avelox) induced thrombotic thrombocytopenic purpura

We report a case of a 66-year-old African-American female who presented with complaints of progressively worsening weakness, shortness of breath on minimal exertion, lethargy for the last few days, and short episodes of aphasia lasting 20–30 seconds. Prior to presentation, she was treated with two courses of moxifloxacin for sinusitis. Laboratory examination was remarkable for anemia and thrombocytopenia with elevated lactate dehydrogenase and no evidence of renal failure. Peripheral smear showed numerous schistocytes and she was diagnosed with thrombotic thrombocytopenic purpura. Moxifloxacin was identified as the offending agent. The patient was treated with prednisone and plasmapheresis. To the best of our knowledge, this is the first reported case of thrombotic thrombocytopenic purpura associated with the use of moxifloxacin. Although rare, physicians should be aware of this serious complication associated with its use.

Antibodies causing thrombocytopenia in patients treated with RGD-mimetic platelet inhibitors recognize ligand-specific conformers of αIIb/β3 integrin

Arginine-glycine-aspartic acid (RGD)-mimetic platelet inhibitors act by occupying the RGD recognition site of α(IIb)/β(3) integrin (GPIIb/IIIa), thereby preventing the activated integrin from reacting with fibrinogen. Thrombocytopenia is a well-known side effect of treatment with this class of drugs and is caused by Abs, often naturally occurring, that recognize α(IIb)/β(3) in a complex with the drug being administered. RGD peptide and RGD-mimetic drugs are known to induce epitopes (ligand-induced binding sites [LIBS]) in α(IIb)/β(3) that are recognized by certain mAbs. It has been speculated, but not shown experimentally, that Abs from patients who develop thrombocytopenia when treated with an RGD-mimetic inhibitor similarly recognize LIBS determinants. We addressed this question by comparing the reactions of patient Abs and LIBS-specific mAbs against α(IIb)/β(3) in a complex with RGD and RGD-mimetic drugs, and by examining the ability of selected non-LIBS mAbs to block binding of patient Abs to the liganded integrin. Findings made provide evidence that the patient Abs recognize subtle, drug-induced structural changes in the integrin head region that are clustered about the RGD recognition site. The target epitopes differ from classic LIBS determinants, however, both in their location and by virtue of being largely drug-specific.

Piperacillin and vancomycin induced severe thrombocytopenia in a hospitalized patient

In hospitalized patients with complex medical problems on numerous drugs, thrombocytopenia may have a multiple confounding etiology. Keeping this in mind, it is of utmost importance to monitor the platelet count regularly during hospitalization and on subsequent follow-up visits, even after the most probable etiology has been identified/most likely causative drug has been withdrawn. Isolated thrombocytopenia with no evidence of microangiopathic hemolysis on the peripheral blood smear in an acutely ill hospitalized patient implicated sepsis, disseminated intravascular coagulation and drugs as the most probable causes. Our patient represents an uncommon case of antibiotic-induced severe immune thrombocytopenia, as he developed both vancomycin-dependent and piperacillin-dependent antibodies, while being treated for cellulitis (vancomycin-specific antibodies of the IgG isotype, and both IgG and IgM antibodies specific for piperacillin were identified in laboratory testing). Vancomycin was stopped before the reports were available. Following this, the patient's platelet count showed a transient upward trend, but then the thrombocytopenia worsened drastically reaching a nadir of 10,000/µL. The platelet count returned to normal only after piperacillin/tazobactam was stopped after a week, thus establishing it as the cause of the more severe thrombocytopenia, which occurred later on; this was subsequently confirmed by the laboratory results. Vancomycin is an established cause of drug-induced immune thrombocytopenias, especially in acutely ill, hospitalized or elderly patients, whereas incidents of piperacillin/tazobactam-induced immune thrombocytopenia are uncommon. In case clinical suspicion is high, workup should include immunoprecipitation and flow cytometry studies to confirm antiplatelet antibodies.

Review of Continuing Education Course on Hemostasis

The continuing education course “Hemostasis” provided a comprehensive review of hemostasis and selected perturbations of the underlying processes as well as an assessment of hemostasis in animal models and preclinical testing environments. The session began with a review of the current state of understanding of hemostasis and how the waterfall or cascade of activation has transformed to the current cell-based, membrane-associated sequence of highly regulated events. The specific mechanisms of drug-induced thrombocytopenia were then presented, followed by a discussion of the relationships of coagulation and platelets in inflammation and cancer metastasis and platelet activity. Evaluation of hemostasis and platelet function in animals and especially in the environment of the contract research facility concluded the session.

Identifying drugs that cause acute thrombocytopenia: an analysis using 3 distinct methods

Drug-induced immune thrombocytopenia (DITP) is often suspected in patients with acute thrombocytopenia unexplained by other causes, but documenting that a drug is the cause of thrombocytopenia can be challenging. To provide a resource for diagnosis of DITP and for drug safety surveillance, we analyzed 3 distinct methods for identifying drugs that may cause thrombocytopenia. (1) Published case reports of DITP have described 253 drugs suspected of causing thrombocytopenia; using defined clinical criteria, 87 (34%) were identified with evidence that the drug caused thrombocytopenia. (2) Serum samples from patients with suspected DITP were tested for 202 drugs; drug-dependent, platelet-reactive antibodies were identified for 67 drugs (33%). (3) The Food and Drug Administration's Adverse Event Reporting System database was searched for drugs associated with thrombocytopenia by use of data mining algorithms; 1444 drugs had at least 1 report associated with thrombocytopenia, and 573 (40%) drugs demonstrated a statistically distinctive reporting association with thrombocytopenia. Among 1468 drugs suspected of causing thrombocytopenia, 102 were evaluated by all 3 methods, and 23 of these 102 drugs had evidence for an association with thrombocytopenia by all 3 methods. Multiple methods, each with a distinct perspective, can contribute to the identification of drugs that can cause thrombocytopenia.

Acute thrombocytopenia: an unusual complication occurring after drug-eluting microspheres transcatheter hepatic chemoembolization

Image-guided transcatheter hepatic chemoembolization (TACE) is accepted worldwide as an effective treatment for patients with unresectable hepatocellular carcinoma and liver metastases from neuroendocrine tumors, colorectal carcinomas, and uveal melanomas. Although the technique is relatively safe, it has been associated with several complications. We report the cases of two patients with colorectal liver metastases who developed acute thrombocytopenia a few hours after TACE. To our knowledge, acute thrombocytopenia occurring after TACE with drug-eluting microspheres has not yet been reported. Here we discuss the hypothetical etiopathogenetic mechanisms.