Complications after bariatric surgery, can be divided into two types of short-term, such as leaks of the anastomosis, bleeding, and embolism and long-term, such as ulcers, obstruction, malabsorption of nutrients, vitamins and minerals (7). In addition, some rare side effects may also occur, which is necessary for all those who work in this field to be familiar with them and its causes and how to treat. Thrombocytopenia in adults, known as the platelet count less than 150,000, that is divided into mild (100,000 - 150,000 /microL), moderate (50,000 to 99,000 /microL) and severe (less than 50000 /microL) (8). In 5.2% of cases the platelet count may be less than 150,000 as a normal variant (8). In some cases, despite the drop in platelet counts, it maybe still be equal to or greater than 150,000. Therefore, the platelet count should be compared with the initial platelet counts, and recent platelet drop of more than 50% of the initial amount, needs to investigate (9).
The most common cause of thrombocytopenia fallowing surgery are: hit, disseminated intravascular coagulation (dic), thrombotic thrombocytopenic purpura (TTP), dilution from fluid resuscitation or massive transfusion, Medications, bone marrow suppression due to sepsis or infection, alcohol consumption, nutrients such as folic acid or copper deficiencies, or can be idiopathic (10). Of the drugs, antibiotics like Sulfonamides, Ampicillin, Piperacillin, Vancomycin, Rifampin or Antiepileptic agents such as Carbamazepine, Phenytoin, and Quinine could be noted (11). If the patient has not already been taking these drugs, thrombocytopenia occurs in 1 to 2 weeks later, and after stopping, 5 - 7 days later becomes normal, and no more treatment is required (9, 12). Among the drugs used in this patient, none of them could cause a drop in platelets count.
Folate, vitamin B12 and copper deficiencies, can cause a mild pancytopenia, but isolated thrombocytopenia has also been reported after bariatric surgery especially gastric bypass (13). In this patient, blood levels of vitamins and minerals checked, and was normal. Also there was no evidence of sepsis in this patient.
According to previous use of Heparin for her DVT and recent prescription of prophylactic Heparin; HIT and Non-immune Heparin-associated thrombocytopenia (HAT) was diagnosed at the first step.
Thrombocytopenia often occurs in the ICU-admitted patients. Although there may be various reasons, the use of heparin is considered as the cause of this phenomenon increasingly. Table 1 shows the differences between these two diseases (14).
HIT is an immunologic disorder, mediated by antibodies against heparin-platelet factor complex 4 (PF4). It is a rare cause of thrombocytopenia, and its incidence in patients who receive heparin, is 0.5 - 2 percent, and in patients who are hospitalized in the ICU is 39.0 - 48.0 percent (10).
Table 1.
The Differences Between HIT and Non-Immune HAT Include
Variables | Non-Immune HAT | HIT |
---|
Onset | Within 4 days | Usually 5 - 14 (may be sooner) |
Platelet count | Typically 100 - 150k | Typically 20 - 150k |
Median 50k |
Rarely < 20k |
Sometime falls > 30%,but remain > 150k |
Complication | None | Thrombo-embolic lesions |
Incidence | 5% - 30% | 1% at 1 week; 3% at 2 weeks |
Recovery | 1 - 3 days | 5 - 7 days |
Cause | Benign, small platelet aggregates | IgG-mediated strong platelet activation |
HIT Diagnostic criteria’s, briefly called Ts4, are: (14-16)
1. Platelets decrease after heparin therapy (Thrombocytopenia). Often platelet count drops about 50% or less, but in 10% of cases, there may be a drop in platelet count between 30 to 50% and usually doesn’t reach under 20000/mcl unless when is accompanied with disseminated intravascular coagulation (DIC).
2. Thrombocytopenia may appear 5 - 14 days after initiation of heparin and if heparin had taken before, may presented sooner.
3. The incidence of thromboembolic complications while receiving heparin (thrombosis or another sequel).
4. Rule out Other causes, such as sepsis, etc.
The definite diagnosis is based on laboratory tests of antibodies against PF4-heparin complex detection. Immunoassay methods which done by most of the laboratories has low sensitivity while Platelet activation assay Methods is highly sensitive (negative predictive values, close to 100%) (14).
By discontinuation of the Heparin, recovery takes place at 4 to 14 days later. Direct thrombin Inhibitors such as Argatroban and Dabigatran should be used in these patients (14). Due to the unavailability of laboratory tests in many centers, the majority of physicians assume HIT as the cause of thrombocytopenia in patients who receive Heparin. So, they discontinue the patient’s Heparin; but, if there was another cause for it; the thrombocytopenia doesn’t improve and deprived the patient of taking this effective drug. Specifically, the impact of alternative medications is not as well as Heparin. On the other hand, in patients with bypass surgery who have oral medication intolerance or malabsorption, intravenous Heparin administration is much more effective than oral alternative medications (17).
In this case, there is previously heparin intake, and recently she takes Heparin again for 2 weeks, probability of HIT was clinically high. However, according to confirmed pulmonary embolism, discontinuation of heparin injection, puts the patient in high risk of mortality. Therefore, due to the lack of serologic tests feasibility at the admitted hospital, blood samples for this test, was sent to another laboratory, and after negative results, this diagnosis was ruled out, and Heparin injections were not disconnected.
After bariatric surgery, the risk of DVT and pulmonary embolism (PE) is high. Because there are more risk factors. Such as BMI above 25 kg/m2, intra-operative anti-Trendelenburg position, high gas pressure in the abdomen during laparoscopic surgery, and reduced fibrinolysis activity. Despite receiving Heparin in these patients, the incidence of clot formation in the lower extremities, is 0.79 percent (18). The risk of clot formation will be remain up to 30 days after surgery (19). If you suspect DVT or PE, therapeutic dose of Heparin should be started.
Idiopathic Thrombocytopenic Purpura (ITP) is an autoimmune disease that was first described in 1916 and is due to production of autoantibodies against platelets. Its incidence is 9.3 cases per 100,000 per year. However, the causes of the former cases is unknown, But the latter, can result from other autoimmune disorders, infections, vaccinations, lymphoproliferative disorders, congenital immune deficiencies, and medications (20).
ITP diagnosed by thrombocytopenia below 100,000, and the absence of splenomegaly and secondary causes. The standard treatment is Corticosteroid (8, 9). Assistive prescription of intravenous immunoglobulin, sometimes is necessary. 80 to 90 percent of patients, response to this treatment. In refractory cases, other treatments such as Splenectomy or prescription of Rituximab or Romiplostim can be used (15).
3.1. Conclusion
ITP is a rare complication of Laparoscopic omega gastric bypass, and responds well to corticosteroids. Although this patient had a previous history of DVT and heparin use; but laboratory data ruled out HIT. The diagnosis of ITP comes up for this patient after all other causes of thrombocytopenia ruled out. On the other hand; concurrent increase in platelet levels and corticosteroid prescription; helped to confirm the diagnosis. So because of the short timing interval (2 weeks) of happening this condition after bariatric surgery; it strongly comes to mind to be related with the operation or even be one of its complications. But; it also needs more study on similar cases in future to assess all neglected aspects of the condition. So; thrombocytopenia in patients receiving Heparin needs a complete workup and before discontinuation of Heparin, HIT must be ruled out in high risk patients.
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