Potential Hematology and Nutritional Complications of Bariatric Surgery

Review Article

Ann Hematol Oncol. 2018; 5(5): 1209.

Potential Hematology and Nutritional Complications of Bariatric Surgery

Al-Jafar H¹*, Al-Zamil K², Al Ageeli M³, Alhaifi M4 and Al-Sabah S4

1Department of Hematology, Amiri Hospital, Kuwait

2Department of General Surgery, Amiri Hospital, Kuwait

3Department of Clinical Biochemistry, Amiri Hospital, Kuwait

4Department of General Surgery & Bariatric Surgery, Amiri Hospital, Kuwait

*Corresponding author: Hassan Al-Jafar, Consultant Hematologist, Department of Hematology, Amiri Hospital, Kuwait

Received: June 08, 2018; Accepted: July 02, 2018; Published: July 11, 2018


Bariatrics is a specialized field of medicine that deals with the etiology, prevention and management of patients with morbid obesity. Surgical and nutritional complications are two adverse effects associated with bariatric surgery. For patients in recovery, post-bariatric surgical treatment and management often involves the care of a hematologist. Long term nutritional problems may develop following bariatic surgery and should be considered by physicians, although long-term nutritional complications are often rare or just temporary. Multivitamin and iron supplementation are required as part of a patient’s prophylactic postbariatric surgical management protocol; therefore, the patient’s adherence to vitamin supplementation should be checked during follow up appointments. This review aims to emphasize the potential multi systemic hematological and nutritional complications of bariatric surgery. Vitamin deficiencies such as iron and vitamin B12 sometimes affect patients and therefore physicians should be aware of this in the treatment of patients with a history bariatric surgery. Inquiring about a patient’s history of bariatric surgery needs to be one of the first questions to ask a patient who is presenting with vitamin deficiencies as this can cause multi system abnormalities. Many patients are lost to follow up after bariatric surgery and come back with complications. Therefore, the importance of maintaining follow up appointments should be emphasized.

Keywords: Bariatric; Hematology; Nutrition; Vitamins


The term “bariatric” was used for the first time on 1965 [1]. Bariatrics in medicine deals with the etiology, prevention and management of morbid obesity. Body Mass Index (BMI) is derived from a patient’s weight and height to assess the degree of obesity [2]. The BMI is widely applicable in various clinical fields as it is necessary to assess the dose of many drugs [3]. Bariatric surgery is currently the most used and effective measure to treat patients with morbid obesity and to help reduce metabolic disorders such as Diabetes mellitus, dyslipidemia and hypertension [4]. The U.S. National Institutes of Health recommends bariatric surgery for obese people with a BMI of 40 kg/m² [5]. Indication for bariatric surgery could be appropriate for those individuals with a BMI of 35-40 kg/m² without comorbidities or a BMI of 30-35 kg/m² with significant comorbidities [6]. Obesity is associated with severe fat deposition in many organs that may cause serious, adverse effects on health [7] and individuals with BMIs exceeding the healthy range have a much greater risk for medical issues [8]. Usually, exercise, diet and behavior therapy should be the first-line of treatment for individuals with obesity [9], as medical therapy for severe obesity has limited short and longterm success [10]. Bariatric surgery often leads to improvements in a patient’s quality of life and obesity-related diseases [11]; moreover, improvements in psychological health have also been observed [12]. Major complications due to bariatric surgery have been reported in 3.3% of patients [13]. Surgical complications may occur as adverse events early in the post-operative period, especially in those excessively overweight [14]. Nutritional complications are considered late side effects and require attention by the treating surgeon. These complications are often associated with gastrointestinal malabsorption which needs to be addressed to prevent chronic health conditions such as neurological complications associated with longstanding severe vitamin B12 deficiency [15].

I-Potential Surgical Complications


Bleeding is an adverse outcome in many types of surgical procedures. However, the amount of bleeding can be reduced by adequate pre-operative assessment to identify and correct disorders due to other comorbidities. Surgical bleeding can arise from technical causes as well as the presence of a bleeding disorder [16]. The onset of early bleeding is usually = 24 hours after the end of the surgery, the location is either intraluminal or extra luminal, and the severity of the bleeding may be either mild or severe [17]. Bleeding due to a disorder can be categorized into three groups: disorders of platelet function or number, disorders of clotting factors, or a combination of these, and thirdly, the bleeding could be due to vascular or pathological localized lesions [18]. The incidence of bleeding ranges between 0% and 4.4% and varies according to the different procedures performed. However, bleeding remains a known and limited complication in bariatric surgery [19].


Deep Vein Thrombosis (DVT) is one of the serious complications of bariatric surgery in patients with morbid obesity. Patients with postoperative DVT could be asymptomatic [20] or DVT could simply manifest as chronic venous hypertension, which subsequently develops into varicose veins. Factors that could influence thrombus formation are alterations in blood flow, changes in the vessel wall, alterations in blood constituents and viscosity, and inhibition of the fibrinolysis system. Once DVT occurs, the fate of the thrombus depends on the persistence of factors involved in its formation. Many thrombi will spontaneously lyse or will shrink, but others may extend and embolize, posing a threat to the patient [21]. The reported incidence of DVT after bariatric surgery varies widely, from 0.2% to1.3% at 30 days [22] and to 0.42% at 90 days [23].


All patients who undergo surgery are at risk for Pulmonary Embolism (PE). During surgery, PE often initially manifests as hemodynamic instability [24]. PE occurs in approximately 0.3% to 1.6% of the general population that undergoes surgery [25]. The initial hemodynamic insult in PE is the obstruction of blood flow, which causes emboli in the pulmonary vasculature that disrupt pulmonary outflow, cause an acute increase in right ventricular impedance, and initiate neural reflexes and the release of pulmonary vasoconstrictors into the circutation [26]. The reported incidence of PE in patients undergoing open bariatric surgery with prophylaxis measures ranges from 0.36% to 3.0% [27].

II-Potential Nutritional Complications

A-Vitamin Deficiencies

Micronutrients, including trace elements, water, and fat-soluble vitamins can become depleted in patients during the post-bariatric surgical recovery period, and such elements are essential factors that mainly serve as enzymatic cofactors in biochemical pathways and metabolic processes [28]. Micronutrient deficiencies vary in frequency according to the type of surgery performed [29,30]. Adverse events after bariatric surgery can lead to a wide range of symptoms, most commonly anemia (10%-74%) and neurological dysfunction (5%- 9%) [31,32]. Determining the exact risk for developing micronutrient deficiencies is challenging as there is no consensus on the appropriate amount of vitamin and mineral supplementation required across bariatric surgery programs, and therefore, supplementation practices vary widely [33]. It is clear that micronutrient deficiencies are relatively common in patients before and after all types of bariatric surgery; therefore, it is important to screen patients at baseline and at least annually [34].

Thiamine (vitamin B1) deficiency

Thiamine deficiency is common after bariatric surgery lead to the combination of a reduction in acid production by the gastric pouch, restriction of food intake, and frequent episodes of vomiting [35,36]. Thiamine deficiency accompanied by peripheral neuropathy is characterized by polyneuropathy with paresthesia of the extremities, especially the legs, reduced knee-jerk and other tendon reflexes, severe progressive weakness, muscle wasting, and increased susceptibility to infections [37]. Thiamine deficiency is associated with a condition called Beriberi syndrome, which presents as mental confusion, anorexia, muscular weakness, ataxia, peripheral paralysis, tachycardia; thiamine deficiency associated with edema is known as wet beriberi [38]. Red blood cell megaloblastic changes in thiamine deficiency could cause megaloblastic anemia [39], which is reversible and could be corrected with pharmacologic doses of thiamine (vitamin B1) [40] (Table 1).

Citation: Al-Jafar H, Al-Zamil K, Al Ageeli M, Alhaifi M and Al-Sabah S. Potential Hematology and Nutritional Complications of Bariatric Surgery. Ann Hematol Oncol. 2018; 5(5): 1209.