Fatal Reactions Research Articles

Advances in multimodality imaging and the application of new cardiac imaging technologies for radiation‐induced heart disease

AbstractRadiation‐induced heart disease (RIHD) is a heterogeneous, delayed, and potentially fatal adverse reaction to radiation that can damage all structures of the heart, including the pericardium, myocardium, coronary arteries, valves, and conduction system, leading to a series of diseases. Acute and chronic disease processes play a role in the development of RIHD, the onset times of which range from months to decades. However, the clinical manifestations of RIHD are usually insidious, overlap with several other diseases, and lack specificity. Cardiovascular imaging is essential for early diagnosis, follow‐up, and outcome assessment in patients with RIHD. This review first describes the pathogenesis and clinical manifestations of RIHD before providing an overview of the practical approaches and research advances in multimodal cardiovascular imaging in patients with RIHD, including echocardiography, cardiac magnetic resonance (CMR) and nuclear medicine, and cardiac computed tomography (CT). Then, the value of new cardiac imaging assessments for the early diagnosis of RIHD is described, particularly with relation to speckle‐tracking echocardiography, extracellular volume fraction assessment as a quantitative CMR technique, CMR myocardial strain assessment, positron emission tomography‐CT myocardial perfusion imaging, CT‐ECV, and CT strain assessment, amongst others. In addition, the advantages and disadvantages of each screening technique are compared with the aim of better guiding the follow‐up and diagnosis of subclinical RIHD and preventing cardiovascular events.

El pediatra de Atención Primaria y la anafilaxia

Anaphylaxis is a severe, rapid and potentially fatal allergic reaction. The diagnosis of anaphylaxis is clinical and must be early. It appears in the first 2 hours after exposure to the allergen, in the first 30 minutes in food allergy and earlier with intravenous drugs or hymenoptera stings. Cutaneous symptoms are generally the first to appear and are present in most cases, more than 80%. They may be mild or transitory, or absent in 18% of cases. If the cardio-circulatory system is affected, an anaphylactic shock occurs. The most frequent cause in pediatrics is nutrition. There are several cofactors whose presence increases the likelihood of anaphylaxis; the most important are: exercise, medication, fever and stress. The treatment of choice is intramuscular adrenaline. Parents and children should be able to identify the signs and/or symptoms of anaphylaxis in order to implement the treatment prescribed in the written action plan.

Modulation of the Mas-Related G Protein-Coupled Receptor X2 (MRGPRX2) by Xenobiotic Compounds and Its Relevance to Human Diseases.

Mast cells (MCs) are immune cells that reside in tissues; particularly in the skin, and in the gastrointestinal and respiratory tracts. In recent years, there has been considerable interest in the Mas-Related G Protein-Coupled Receptor X2 (MRGPRX2), which is present on the surface of MCs and can be targeted by multiple exogenous and endogenous ligands. It is potentially implicated in non-IgE-mediated pseudoallergic reactions and inflammatory conditions such as asthma or atopic dermatitis. In this paper, we review natural products and herbal medicines that may potentially interact with MRGPRX2. They mainly belong to the classes of polyphenols, flavonoids, coumarins, and alkaloids. Representative compounds include rosmarinic acid, liquiritin from licorice extract, osthole, and sinomenine, respectively. While evidence-based medicine studies are still required, these compounds have shown diverse effects, such as antioxidant, analgesic, anti-inflammatory, or neuroprotective. However, despite potential beneficial effects, their use is also burdened with risks of fatal reactions such as anaphylaxis. The role of MRGPRX2 in these reactions is a subject of debate. This review explores the literature on xenobiotic compounds from herbal medicines that have been shown to act as MRGPRX2 ligands, and their potential clinical significance.

Current update on anaphylaxis: anaphylaxis management in recent guidelines.

Anaphylaxis is a potentially fatal hypersensitivity reaction but frequently underrecognized. Although its incidence rates vary according to geographical location, it seems clear that there has been a general increase in recent years, either because of greater recognition of this entity or because it is progressing proportionally to the presence of allergic diseases in the world. The development of anaphylaxis management guidelines adapted to local or regional needs seems of utmost importance. Furthermore, it is necessary to assess their implementation and their positive effect regarding diagnosing and treating anaphylaxis. In this review we explore the currently existing definitions of anaphylaxis and its epidemiology, the potential triggers of anaphylaxis and guideline recommendations in terms of diagnosis and management, proposing a novel anaphylaxis calculator and reviewing the current scoring methods for anaphylactic episodes.

BBDash: An Electron-based tool for analyzing blood product utilization

Blood transfusions can be associated with side effects ranging from occasional febrile reactions to extremely rare fatal reactions. Monitoring blood product orders and ensuring appropriate utilization is therefore an important strategy to ensure patient safety. However, data extracted from laboratory information systems can be difficult to interpret. We created BBDash, an Electron-based tool that reads Sunquest reports to create easy-to-interpret graphs related to blood product utilization.

Integrating antimicrobial photodynamic therapy into the adjuvant phototherapeutic approach for orofacial manifestations of toxic epidermal necrolysis and Stevens-Johnson syndrome

Characterized by an immune reaction to medications, toxic epidermal necrolysis (TEN) and Steven-Johnson Syndrome (SJS) are potentially fatal mucocutaneous reactions, and their management remains challenging. Considering the promising studies regarding the use of laser in managing orofacial lesions, this study aimed to report two cases in which children presenting with TEN and SJS were treated using a combination of antimicrobial photodynamic therapy (aPDT) and photobiomodulation therapy (PBMT) concurrently with conventional supportive care. The treatment proposed herein resulted in significant clinical improvement of the children's oral condition within a few days, enabling the reintroduction of oral feeding. Within the limitations of the study, the cases reported suggest that the adjuvant combination of PBMT and aPDT may be beneficial for improving the oral condition of children afflicted with oral injuries induced by TEN and SJS.

A Potentially Fatal Reaction to Dipyrone: Should we Continue Using it?

A Potentially Fatal Reaction to Dipyrone: Should we Continue Using it?

Death following COVID-19 vaccination: A case report

Vaccines are necessary to reduce the mortality and morbidity of infectious diseases. It has played a vital role in the ongoing coronavirus disease 2019 (COVID-19) pandemic. Different types of vaccines have been developed to combat the pandemic. Adverse events following immunization including anaphylaxis have been reported for all types of COVID-19 vaccine. Anaphylaxis is common in a person who has a history of allergic reactions. Adverse reactions develop within minutes or a few hours after vaccination. Thus, in India, vaccine recipients are made to stay in the medical facility for 30 min for observation.
 Herein, we report the case of a 23-year-old woman who succumbed after 24 hours of taking COVISHIELD ChAdOx1 nCoV-19 Corona Virus Vaccine (recombinant). She did not have any symptoms after vaccination during her observation at the medical facility and did not have a history of allergic reactions. She was brought dead to M.S. Ramaiah Hospital, and the autopsy revealed pulmonary edema. Antibodies to COVID-19, inflammatory markers, serum IgE, and coagulation indicators in the postmortem blood sample were high. The cause of death was attributed to a delayed allergic reaction to COVISHIELD vaccine. Newer vaccines can cause fatal allergic reaction, sometimes later than expected, even when cutaneous reactions may not be present.

Beyond the Clinic Walls: Fostering Well-Being in a Client with Schizoaffective Disorder (SAD) Through Home Care and Clozapine Therapy - A Case Report

Schizoaffective disorder SAD is a chronic severe and disabling illness associated with concurrent presentation of symptoms of schizophrenia and affective disorders. The mainstay of treatment is a combination of antipsychotic medications and depending on the subtype of schizoaffective disorder either mood stabilizers or antidepressants are given. Clozapine is a second-generation antipsychotic used in the treatment of SAD. Clozapine-induced agranulocytosis has the highest risk of occurrence during the first few months of treatment. Other common side effects are sialorrhea constipation dehydration and hyperglycaemia. Adequately managing side effects can improve adherence and quality of life. Physical health should be monitored at each clinical review particularly in the first few months of treatment to reduce the occurrence of serious sometimes fatal adverse reactions. Many clients find clozapine to help with their psychosis but they often need to balance the positive effect of psychosis with some of the side effects that clozapine can cause.

Dapsone-Induced DRESS Syndrome: A Case Report

Drug reaction with eosinophilia and systemic symptoms DRESS syndrome sometimes known as drug-induced hypersensitivity syndrome represents a unique and potentially life-threatening adverse response triggered by medications. It typically presents as a skin rash resembling measles affecting individuals of various age groups accompanied by symptoms like fever swollen lymph nodes irregular blood cell counts and a range of multiorgan issues. Its incidence is 11000 to 10000 exposures and its mortality is 10-20. We report a case of a patient diagnosed with DRESS syndrome secondary to Dapsone use. The main objective of this case report is to describe the characteristics complications and treatment of drug-induced DRESS syndrome. The presented case report of a 17-year-old female patient admitted to a tertiary care hospital in Bengaluru with a history of peeling skin all over the body for 10 days and was diagnosed with DRESS syndrome secondary to Dapsone use. During the admission she was prescribed Wysolone and Atarax Hydroxyzine. The patient was simultaneously treated with local ointments and her condition symptomatically improved. This case emphasizes the fatal and life-threatening adverse reactions of Dapsone and their management.

An Appy That Needs Epi: An Atypical Presentation of Anaphylaxis.

An Appy That Needs Epi: An Atypical Presentation of Anaphylaxis.

Insights into Mefenamic Acid-Induced Allergic Reactions: A Comprehensive Clinical and Research Review

This study investigates the incidence of Drug Rash with Eosinophilia and Systemic Symptoms (DRESS) syndrome associated with the over-the-counter non-steroidal anti-inflammatory drug (NSAID) mefenamic acid. Approximately 10% of individuals exposed to mefenamic acid experience DRESS syndrome, a severe and potentially fatal allergic reaction characterized by fever, skin rash, lymphadenopathy, hematological abnormalities, and internal organ involvement. Leukocytosis with eosinophilia (90%) and mononucleosis (40%) has been linked to certain cases, emphasizing the diversity of clinical presentations. The causative medication must be promptly discontinued upon identification of DRESS syndrome, with documented evidence indicating improved prognosis with early drug removal. Despite the severity of these reactions, the study sheds light on the alarming accessibility of mefenamic acid and other banned medications in developing nations, particularly exemplified by the Indian Pharmacopoeia Commission’s alert on mefenamic acid issued on December 7, 2023. The lack of effective law enforcement and medical awareness poses significant challenges, allowing banned drugs, including Nimesulide and Rofecoxib, to persist in the market despite being banned by the USFDA. This research underscores the critical need for global collaboration to address regulatory gaps, enhance medical awareness, and enforce stringent measures to restrict the availability of harmful medications in developing nations. Urgent attention to these issues is imperative to safeguard public health and ensure the effective implementation of drug regulations on a global scale.

Variation in the Allergenicity of Scrambled, Boiled, Short-Baked and Long-Baked Egg White Proteins.

Hen's egg white (HEW) is the most common cause of food allergy in children which induces mild to fatal reactions. The consultation for a proper restriction is important in HEW allergy. We aimed to identify the changes in HEW allergenicity using diverse cooking methods commonly used in Korean dishes. Crude extract of raw and 4 types of cooked HEW extracts were produced and used for sodium dodecyl-sulfate polyacrylamide gel electrophoresis (SDS-PAGE), enzyme-linked immunosorbent assay (ELISA), and ELISA inhibition assays using 45 serum samples from HEW allergic and tolerant children. Extracts were prepared; scrambled without oil for 20-30 seconds in frying pan without oil, boiled at 100°C for 15 minutes, short-baked at 180°C for 20 minutes, and long-baked at 45°C for 12 hours with a gradual increase in temperature up to 110°C for additional 12 hours, respectively. In SDS-PAGE, the intensity of bands of 50-54 kDa decreased by boiling and baking. All bands almost disappeared in long-baked eggs. The intensity of the ovalbumin (OVA) immunoglobulin E (IgE) bands did not change after scrambling; however, an evident decrease was observed in boiled egg white (EW). In contrast, ovomucoid (OM) IgE bands were darker and wider after scrambling and boiling. The IgE binding reactivity to all EW allergens were weakened in short-baked EW and considerably diminished in long-baked EW. In individual ELISA analysis using OVA+OM+ serum samples, the median of specific IgE optical density values was 0.435 in raw EW, 0.476 in scrambled EW, and 0.487 in boiled EW. Conversely, it was significantly decreased in short-baked (0.406) and long-baked EW (0.012). Significant inhibition was observed by four inhibitors such as raw, scrambled, boiled and short-baked HEW, but there was no significant inhibition by long-baked HEW (IC50 > 100 mg/mL). We identified minimally reduced allergenicity in scrambled EW and extensively decreased allergenicity in long-baked EW comparing to boiled and short-baked EW as well as raw EW. By applying the results of this study, we would be able to provide safer dietary guidence with higher quality to egg allergic children.

Non-surgical management of a large facial antibioma with photobiomodulation as a therapeutic adjunct: A case report

The injudicious overuse of antibiotics has led to a worldwide rise in antibiotic-resistant bacterial strains. Apart from antibiotic resistance and misuse of resources, inappropriate use of antibiotics also increases the possibility of potentially fatal anaphylactic reactions and makes patients vulnerable to unwarranted side effects. Sometimes, prolonged and unnecessary use of these antibiotics, either by the treating dentist or by the patient, combined with improper drainage of the pulpal canal, may lead to the formation of a tough fibrous swelling known as antibioma. The most commonly reported treatment modality for antibioma is surgical excision and extraction of the tooth involved. However, the present case reports a non-surgical management of a large facial antibioma using photobiomodulation (PBM) (neodymium-doped yttrium aluminum garnet, 1064 nm) for management of an antibioma developed in relation to a long-standing chronic apical periodontitis in mandibular molar.

IgE and anaphylaxis specific to the carbohydrate alpha-gal depend on IL-4

Alpha-gal (Galα1-3Galβ1-4GlcNAc) is a carbohydrate with the potential to elicit fatal allergic reactions to mammalian meat and drugs of mammalian origin. This type of allergy is induced by tick bites, and therapeutic options for this skin-driven food allergy are limited to the avoidance of the allergen and treatment of symptoms. Thus, a better understanding of the immune mechanisms resulting in sensitization through the skin is crucial, especially in the case of a carbohydrate allergen for which underlying immune responses are poorly understood. We aimed to establish a mouse model of alpha-gal allergy for in-depth immunologic analyses. Alpha-galactosyltransferase 1-deficient mice devoid of alpha-gal glycosylations were sensitized with the alpha-gal-carrying self-protein mouse serum albumin by repetitive intracutaneous injections in combination with the adjuvant aluminum hydroxide. The role of basophils and IL-4 in sensitization was investigated by antibody-mediated depletion. Alpha-gal-sensitized mice displayed increased levels of alpha-gal-specific IgE and IgG1 and developed systemic anaphylaxis on challenge with both alpha-gal-containing glycoproteins and glycolipids. In accordance with alpha-gal-allergic patients, we detected elevated numbers of basophils at the site of sensitization as well as increased numbers of alpha-gal-specific B cells, germinal center B cells, and B cells of IgE and IgG1 isotypes in skin-draining lymph nodes. By depleting IL-4 during sensitization, we demonstrated for the first time that sensitization and elicitation of allergy to alpha-gal and correspondingly to a carbohydrate allergen is dependent on IL-4. These findings establish IL-4 as a potential target to interfere with alpha-gal allergy elicited by tick bites.

Rare Event of Anaphylaxis Reaction in a Rabies Post-Exposure Prophylaxis Vaccine: A Case Report

Background. One of the most fatal infectious illnesses, rabies can result in severe symptoms in humans and almost 100% fatality if patients don't receive prompt and sufficient PEP (Post Exposure Prophylaxis). Despite the rarity of allergic responses following rabies immunization, vaccines that protect against infectious illnesses can cause anaphylaxis. Determine if the patient will respond quickly to therapy, pass away in a matter of minutes, or recover on their own as a result of endogenous adrenaline, angiotensin II, and endothelin I secretion. The care of children suffering from anaphylactic shock will be the main topic of this case report. Case Presentation. A six-year-old male patient was admitted to emergency department with shortness of breath, swelling of the whole face and body, gasping for air, and cyanosis of lips, hands, and feet. Previously, the patient was bitten by a dog on the front and right side of his neck 90 minutes prior. He was sent to the community health care facility and administered PEP immediately. It was administered in two ampules without any direct adverse reactions were seen in the following 30-minute observation. Neither previous illnesses nor allergies were reported by his parents. When the patient arrived in emergency room, cyanosis was evident, and he was agitated. Airway was secured using head tilt and chin lift. Oxygen saturation was 60%, thus was given 10 liters/minutes oxygen. He was then given an intramuscular injection of 1:1000 0.3 mg epinephrine and fluid challenge of 300 cc ringer’s lactate solution. Upon reassessing, his vitals sign was not getting better. He had cardiac arrest, resuscitated, but to no avail. Conclusion. During the treatment of rabies, anaphylaxis reactions were inevitable. Post procedure monitoring and emergency management of anaphylaxis reactions must always be prepared to prevent a fatal adverse reaction. Adequate preparation for both equipment and medical personnel is necessary to produce a better outcome. Keywords: Anaphylaxis, Rabies, Post-Exposure Prophylaxis, Vaccine, Children, Case Report

Arthropods and the skin

AbstractArthropods are responsible for most of the animal‐related emergency room visits each year, and nonvenomous arthropods cause the greatest number of animal‐related deaths in the emergency setting. Physicians should recognize the sequela of common and lethal arthropod bites and stings as they can range from asymptomatic or mild pruritus to fatal anaphylactic reactions. This chapter provides an update on recent advancements in the dermatological manifestations, pathophysiology, and management of conditions caused by arthropod bites and stings. Key topics include emerging treatments for pediculosis, characteristic rashes of mosquito‐borne viral diseases, cutaneous lesions in Chagas disease, new Lyme disease vaccine development, topical Spinosad for scabies, and Loxosceles venom composition and early use of antivenom. Recent research reveals progress in understanding arthropod‐related dermatologic diseases but also persistent knowledge gaps in the literature. This focused update delivers a concise overview of current concepts and developments at the intersection of arthropods and dermatology for clinicians.

Serotonin syndrome: A pharmacovigilance comparative study of drugs affecting serotonin levels.

Serotonin syndrome is a rare and potentially fatal adverse drug reaction caused by serotonergic drugs and is due to an increase in serotonin concentration or activation of the 5-HT receptor in the central nervous system. We analysed adverse events in the US Food and Drug Administration (FDA) Adverse Event Reporting System (FAERS) data set to investigate the main drug classes related to reports of serotonin syndrome and the reporting risk in relation to age and sex. We analysed data from the FAERS database to evaluate the main drug classes related to reports of the serotonin syndrome, and the reporting risk in relation to age and sex. We found 8,997 cases of serotonin syndrome; selective serotonin reuptake inhibitors (SSRIs) was the class of drugs with most reports, followed by opioids and other antidepressants. The highest Reporting Odds Ratios (ROR) for drug classes was for monoamine oxidase (MAO) inhibitors (45.99, 95% confidence interval (CI): 41.21-51.33) and SSRIs (32.66, 95% CI: 31.33-34.04), while the ten active substances with the highest ROR were moclobemide, isocarboxazid, oxitriptane, tranylcypromine, melitracen, phenelzine, linezolid, amoxapine, reboxetine and tryptophan; with values of ROR ranging from 44.19 (95% CI: 25.38-76.94) of tryptophan to 388.36 (95% CI: 314.58-479.46) of moclobemide. The ROR for the most commonly involved drugs was higher in the group of older adults (65 > years old), and higher in males. Prescribers need to be vigilant about drugs that can raise serotonin concentration or influence serotonergic neurotransmission, also when using drugs with less well-known risk for serotonin syndrome, like linezolid and triptans.

Nifedipine-induced agranulocytosis: A rare case report and literature review

Rationale: Drug-induced agranulocytosis (DIAG) is a fatal idiosyncratic reaction characterized by a peripheral neutrophil count <0.5 × 109/L. Almost all classes of medications have been implicated with DIAG. However, agranulocytosis induced by antihypertensive drugs is rare worldwide. To the best of our knowledge, this is the first case of nifedipine-associated agranulocytosis with a positive rechallenge. Patient concerns: An 82-year-old man was admitted to our hospital due to uncontrolled fasting blood sugar. He had a history of hypertension and underwent treatment with nifedipine 6 years prior to admission. Blood tests showed white blood cell count of 2.30 × 109/L with a neutrophil count of 0.49 × 109/L. Diagnosis: Other malignancies that contributed to agranulocytosis were excluded, and the patient was diagnosed with DIAG. Interventions and outcomes: At first, gliclazide, rather than nifedipine, was considered as the culprit for DIAG and it was discontinued. Neutrophil count improved upon hematopoietic growth factors and traditional Chinese medicine. During the follow-up, the neutrophil count decreased again, and nifedipine was thought to be the offending agent for agranulocytosis. The neutrophil count increased to 0.91 × 109/L 2 months after nifedipine discontinuation. However, the patient was re-exposed to nifedipine and the neutrophil count decreased to 0.70 × 109/L. Lessons: Nifedipine-induced agranulocytosis is a rare but serious adverse drug reaction. For any patients with clinical suspicion or diagnosis of DIAG, a full drug history should be chronologically and completely taken in order to identify the suspected agents. Sometimes diagnosis of DIAG is challenging since some patients may be entirely asymptomatic. Management of DIAG starts with immediate discontinuation of the implicated drug. Empirical broad-spectrum antibiotics and hematopoietic growth factors may improve patient outcomes and reduce recovery time.

3Ts Score, an Attempt for Less Testing in Thrombocytopenia Patients with Suspected Heparin Induced Thrombocytopenia (HIT): Retrospective Analysis in a University Hospital Setting

Background: Heparin-induced thrombocytopenia (HIT) is a prothrombotic and potentially fatal adverse drug reaction mediated by platelet-activating antibodies against multimolecular complexes of platelet factor 4 (PF4) and heparin. The 4Ts is a pretest scoring system for HIT that was developed to improve and standardize clinical diagnosis. The strength of the 4Ts score lies in the negative predictive value of a low pretest probability score. Those with a 4T score ≥4 is considered to have moderate to high probability of HIT and should undergo confirmatory laboratory test. Delays in treatment are associated with risk of thrombosis. Immediate cessation of heparin and initiation of a non-heparin anticoagulant is therefore standard of care. Method: This is a single institutional retrospective study. We reviewed the charts of 219 patients with thrombocytopenia with suspected HIT to evaluate the appropriateness of ordering the HIT testing based on the pretest probability of the 4Ts scoring system. All patients had enzyme linked immunosorbent assay (ELISA) test for HIT antibodies (the screening test). We studied tests that were sent from 03\16\2021 through 07\03\2023. The serotonin release assay (SRA) which is the confirmatory test for HIT was only sent for patients who had a positive ELISA test. 4T scores were calculated retrospectively using chart's information available to clinicians at the time of the HIT tests were sent. Results: Out of the 219 patients, 80(36.5%), 120(54.7%) and 19(8.6%) patients had a low, intermediate and high pretest probability respectively. The HIT ELISA test was positive in 33 (15.7%) patients and 196 (84.9%) patients had negative results. HIT ELISA had 100% and 93.5% sensitivity and specificity respectively while the positive and negative predicative values were 60% and 100% respectively. A positive SRA test was reported in 23 patients (10.5% of the total study population). Seventy-nine patients (36% of our total sample) scored 4 points which represents intermediate pretest probability. Out of these 79 patients only 6 (11.3%) patients had a positive ELISA test, and 5 (6.3%) patients had a positive SRA test. Aiming to minimize the HIT over testing we examined the increase in the cutoff point of the intermediate pretest probability from 4 points to 5 points which resulted in significant increase in the sensitivity and positive predictive value of the intermediate pretest probability (75.4% and 21% versus 39% and 12.9% respectively). However, the sensitivity dropped from 90% to 65%. The 4th part of 4Ts score gives points based on the probability of HIT versus other pathology as a cause of the thrombocytopenia. Most of the patients with suspected HIT will score one point out of the 4th part of 4Ts score which makes this part of the score is less helpful in distinguishing between patients with suspected HIT and will result in higher overall pretest probability and more testing. We studied the 3Ts score (the 4Ts scoring system after elimination of the 4th part) effect on the intermediate pretest probability. The cutoff points for the 3Ts score are 1-3, 4-5 and 6 for low, intermediate and high pretest probability respectively. The 3Ts score model resulted in significant increase in the specificity and the positive predictive value (76% and 21.7% versus 39.2% and 12.9% respectively) however the sensitivity dropped from 90% to 65%. The average turnaround time for HIT ELISA test and the SRA test was 2.3 days and 4.4 days respectively. Fifteen patients (21% out the patient had low pretest probability on the 4Ts score), 41 patients (59% of the patient who had an intermediate pretest probability on the 4Ts score) and 13 patients (18.8% of the patients who had high pretest probability on the 4Ts score) started on non-heparinoid anticoagulation meanwhile awaiting on the HIT testing result. Conclusion: Over testing of HIT is common secondary to underuse of 4Ts scoring system. Multicomponent educational interventions to increase the awareness and utility of the 4Ts score in addition to implantation of clinical decision support based on HIT computerized score will help to reduce unnecessary diagnostic testing of HIT in patients with low pretest probability. Increasing the cutoff point of the intermediate pretest probability or applying the 3Ts score model resulted in significant increase in the specificity and the positive predictive value of the 4Ts scoring system on expense of the scoring system sensitivity.