Score twice before you cut once: a clinical case of reconstructive bariatric surgery after obesity surgery in a patient with postoperative hypothyroidism and hypoparathyroidism

Introduction

Obesity is an acute problem in modern life. There are lots of publications, statistical and scientific data on the increasing prevalence and serious complications of obesity. It can be stated that people are losing a fight with the obesity epidemic (pandemic) in the 21st century¹. It refers both to preventive measures (all the proposed preventive strategies turned out to be ineffective) and therapeutic approaches. Unfortunately, in the majority of cases, long-term control of the body weight can be provided neither by pharmaceutical nor by non-pharmaceutical methods [1]. Thus, the search for new strategies is ongoing. In the past decades, surgical methods of treatment for obesity have become widespread. Thus, after bariatric surgery, fast reduction of weight, normalization or improvement of the parameters of lipid and carbohydrate metabolism are registered. What is more important, the achieved effect is long-term and stable [2]. It is known that there are different types of surgeries performed on the digestive organs to decrease body weight. They include restrictive (gastroplasty) surgeries to provide a limited amount of food in the stomach; malabsorptive (bypass) to decrease absorption of nutrients due to a shortening of the intestinal tube involved in the digestion; and a combined type. Along with an evident positive effect (fast weight loss, normalization of lipid and carbohydrate metabolism, these surgeries (especially bypass) are associated with specific complications that can be fatal if not resolved. Bypass surgeries are primarily associated with anastomosis stenosis, infectious complications, dumping syndrome, and the final degree of hypoabsorption (malabsorption syndrome). Hypoabsorption is a condition that is associated with any bypass surgeries and develops because of the exclusion of a part of the small intestine from digestion. Globally, hypoabsorption is the aim of numerous bariatric surgeries because a decrease in the absorption of main nutrients leads to a decrease in calories consumption to a critical level. This results in a bodyweight reduction regardless of physical activities. The main problem is that the gastrointestinal tract absorbs not only proteins, fats, and carbohydrates but also a wide range of other substances that influence the organism greatly. For some of them, the intestine is the only natural and available pathway to the blood. Thus, in the remote period after the surgery, a common problem is a deficiency of calcium, vitamin D, iron, vitamin B12, folic acid, and thiamin [3]. The indication of proper nutrient additives and regular monitoring of laboratory parameters compensates for a deficit of macro and micronutrients. Considering the specified peculiarities of surgical treatment of obesity, precise indications and contraindications for this type of surgery were established, which are described in foreign and Russian clinical recommendations [4]. Thus, surgical methods of treatment of obesity are indicated for patients with BMI ≥ 40 kg/m² (3^rd degree of obesity or morbid obesity) if conservative therapy was not effective or patients with BMI < 40 and severe somatic complications. A decision on a bariatric surgery should be made on an interdisciplinary basis (endocrinologist, surgeon, psychiatrist, therapist, cardiologist, nutritional specialist, etc.). It is necessary to evaluate indications and contraindications, as well as the ratio of benefits and risks that can develop right after the surgery and in the long-term period. At the final stage of discussion, the patient should be involved so that they would be informed about the effects of the surgery and make an informed decision on the surgery considering the negative consequences of postoperative behavior violation and lack of medical monitoring. Postoperative management of bariatric patients and monitoring of laboratory parameters are integral parts of qualitative treatment for such patients. Timely correction of microelements and vitamins in the postoperative period, especially, in the period of intensive body weight loss (first year after the surgery), can compensate for the majority of complications. However, there are situations when effective correction is not possible. In such cases, reconstructive interventions with the inclusion of small intestine parts in the digestion are required, which is associated with major difficulties. The authors present a clinical case with a similar situation, which can be useful for all specialists that face patients with a planned or performed bariatric surgery.

Clinical Case

Patient M., 56 years old applied to the Clinic of Rostov State Medical University (Rostov-on-Don) with complaints about nagging pain, paresthesia in arms and legs, involuntary muscular contractions, finger joint tightness, and periodical stridulous breath. The anamnesis of the patients is of special interest. In 2007, the patient underwent total thyroidectomy with left-sided circular lymphadenectomy and further radioactive iodine therapy. After the surgery, the patient developed hypothyroidism and hypoparathyroidism. A replacement therapy was prescribed for the correction of these conditions (levothyroxine 125 µg, Ca-containing drugs 2000 mg/day, vitamin D 1.0 µg/day). Monitoring of laboratory parameters was made (results dated July 6, 2007): TSH – 1.48 mU/L (referent values: 0.4–4.0 mU/L), 25-OH vitamin D – 70 nmol/L, total calcium – 1.61 mmol/L (referent values: 2.10–2.55 mmol/L), phosphorus – 1.8 mmol/L (referent values: 0.74–1.52 mmol/L), ionized calcium – 0.94 mmol/L (referent values: 1.03–1.23 mmol/L). Considering a long-term anamnesis after the surgery and prescription of not only levothyroxine but also vitamin D and Ca-containing drugs, it can be suggested that the patient underwent parathyroidectomy (no primary medical documentation was provided). Another important aspect is that the patient had a compensated calcium-phosphorus metabolism during the postoperative period.

Eight years after the surgery, the patient faced another problem associated with her health – obesity. In 2015, she applied to one of the centers of bariatric surgery to lose weight (the weight before the surgery was 122 kg, BMI = 41 kg/m², HbA1c – 6.7%, ionized calcium – 1.1 mmol/L). By this time, the patient received 850 mg of metformin, Ca-D3 500 mg + 200 ME, levothyroxine 100 mg/day. Medical records contained the diagnosis verified before the surgery “Third-degree obesity, type 2 diabetes mellitus (without specification of complications), hypertensive disease I degree II stage, CHF 0, primary hypothyroidism at the stage of compensation”. Because of 3rd-degree obesity, comorbid conditions, and inability to lose weight using conservative methods, the patient underwent bariatric surgery. The surgery included a duodenal-ileal bypass with a sleeve gastrectomy. According to the surgery protocol, sleeve gastrectomy was performed (the major curvature, body, and fundus of the stomach were removed and a tube was formed with a wall made of lesser curvature). The duodenum was transected 3 cm distal to the pylorus (the duodenal stump going further to the intestine was sealed with sutures). A small intestine loop was isolated 3.5 m from the ileocaecal angle. An end-to-side ileoileal anastomosis was placed (a small intestine loop was sutured with a 3-cm residual part of the duodenum, and thus, connected with the stomach). The major part of the stomach and 2–2.5 m of the initial part of the small intestine (duodenum and jejunum) were excluded from the digestion. A month after the surgery, because of weight reduction and compensation of carbohydrate metabolism, the diagnosis “diabetes mellitus type 2” was changed for “impaired fasting glycemia”. The third-degree obesity was changed for the second-degree of obesity. Thus, the final diagnosis was “Impaired fasting glycemia. Alimental-constitutional obesity of the 2nd degree (BMI = 39 kg/m²); Hypertensive disease I degree II stage, CH 0; Masked depression”.

The general examination by the endocrinologist showed that the patient had a hypersthenic constitution, BMI = 33 kg/m², the skin had icteric discolor. The patient had a convulsive disorder and a specific position of hands (“obstetrician's hand”). The anterior abdominal wall had postoperative scars. Chvostek’s sign and Trousseau’s sign were positive.

Based on the complaints obtained from the patient, objective examination, and anamnesis, the patient was sent for laboratory tests. The results dated September 12, 2018: TSH – 22.82 µU/L, ionized calcium – 0.59 mmol/L, vitamin 25 (OH) D – 38 ng/ml (target values during the correction for a deficit of vitamin D – 30–60 ng/ml). The obtained data indicated the development of decompensation of hypothyroidism and hypoparathyroidism after bariatric surgery. By the time of examination, the patient received daily i.v. infusions of a 10% solution of calcium gluconate and oral Ca-containing drugs 1000 mg, vitamin D3 (colecalciferol) 2 µg, L-thyroxine 200 µg, and standard antihypertensive therapy.

The compensation for hypothyroidism and hypoparathyroidism in bariatric patients is a complicated issue because of a reduction of the absorptive area of the small intestine. The indication of treatment should be made considering the pharmacokinetics of the drugs. It is known that the absorption of levothyroxine occurs in the ileum. Levothyroxine is absorbed in the stomach, duodenum, and upper part of the jejunum, which is confirmed by the studies on the peculiarities of the pharmacokinetics of levothyroxine after bypass surgeries. These data were obtained due to a cohort of patients with removed digestive organs (as specified above) [5]. However, the pharmacokinetics of the drug is affected by the pH of gastric juice (hydrochloric acid is secreted by parietal cells that are primarily located in the fundus and body of the stomach). Thus, the changes in the pH will require an increase in the dose of L-thyroxin [6]. Calcium is primarily absorbed in the duodenum and jejunum [7]. Vitamin D plays an important role in this process, which is absorbed in the small intestine [8].

In 2007, the patient underwent sleeve gastrectomy, which contributed to changes in gastric pH. According to scientific publications, patients that underwent bypass bariatric surgeries could compensate for hypothyroidism with a sublingual form of levothyroxine [9]. However, in Russia, this pharmaceutical form of this drug is not registered. There is an option of a rectal introduction of the drug [10] but this is inconvenient for everyday use and will decrease the quality of life of the patient.

During bypass surgery, the patient had the duodenum and the major part of the jejunum excluded from digestion, which complicated the absorption of enteral forms of calcium and vitamin D. Lifetime i.v. injections of Ca-containing drugs were not possible. The only available option of conservative therapy was an increase in the doses of the prescribed drugs.

The patient’s therapy was corrected: the dose of oral calcium was raised to 2000 mg/day, an active form of vitamin D (alfacalcidol) 3 µg/day was prescribed [11][12], the dose of levothyroxine was increased to 400 µg/day. Despite these changes, the need in i.v. injections of 10% solution of calcium gluconate remained (10 ml).

A month later (October 11, 2018), laboratory control tests showed the following results: ionized calcium – 0.69 mmol/L (referent values: 1.03–1.23 mmol/L), vitamin 25 (OH) D – 56 ng/ml, non-organic phosphorus – 1.91 mmol/L (referent values: 0.74–1.52 mmol/L). The obtained results showed that the therapy was ineffective. Since the patient needed lifetime replacement therapy, a decision was made on reconstructive surgery to include the duodenum and jejunum into the digestive process to provide calcium absorption. On November 19, 2018, laparoscopic proximalization of the anastomosis was performed. The protocol of the surgery included the isolation of the ileum 50 cm long adjoining to the duodenal-ileal anastomosis, formation of an anastomosis between a distal end of the isolated segment of the intestine and duodenal stump, and restoration of the small intestine patency with an ileoileal anastomosis. Thus, all the length of the small intestine was included in the digestive process.

Three months after the reconstructive surgery, the weight of the patient was 81 kg (weight loss continued despite reconstructive surgery); BMI = 27 kg/m²; ionized Ca – 1.12 mmol/L; HbA1c – 4.5%. It was possible to reduce the dose of the prescribed drugs: L-thyroxin 125 µg, oral Ca-containing drugs 1500 mg, vitamin D3 – 1.0 µg. The correction of hyperglycemia along with injections of Ca-containing drugs was not needed. Phosphorus-calcium metabolism and hypothyroidism were compensated by the indication of oral forms of drugs.

Despite the presence of indications for surgical treatment of obesity in this patient, the primary bariatric surgery was irrational because of underestimation of contraindications associated with the peculiarities of the pharmacokinetics of the replacement therapy after total thyroidectomy and parathyroidectomy. Although the aim of the surgery was achieved (the bodyweight reduced, carbohydrate disorders were corrected, arterial hypertension was stabilized), the patient’s life was threatened by the failure to normalize the levels of Ca in the blood and compensate for hyperthyroidism with medication. This mistake was corrected with reconstructive surgery, which improved the patient’s condition.

CONCLUSION

The present clinical case revealed the necessity of the study and informing of endocrinologists, physicians, and nutrition specialists on the peculiarities of bariatric surgeries, their influence on macro and microelements, and pharmaceutical drugs. The data on these peculiarities should be available not only for doctors that work at bariatric centers but also for a wide range of specialists that can encounter the treatment of bariatric patients in the remote postoperative period. Annually, hundreds of thousands of bariatric surgeries are performed. They proved their safety and effectiveness in the treatment of obesity and type 2 diabetes mellitus. The rate of such surgeries in Russia is increasing. There are no doubts that soon, any doctor will face a patient after bariatric surgery that would require pharmacotherapy. The peculiarities of absorption of the indicated drugs must be accounted for in the identification of contraindications to bariatric surgeries. In some cases, like in the presented case, a reverse reconstruction can be needed when the patient’s condition is not improved by medication. Such situations require a thorough approach to the establishment of indications and contraindications for bariatric surgeries, especially those that involve bypass techniques, for each patient individually. A decision on such intervention should be made by a multidisciplinary team meeting. Thorough postoperative monitoring of bariatric patients should be conducted, especially in the first year after the surgery. Besides, the authors believe that considering the high efficiency of this surgical method for the treatment of obesity, it is necessary to develop “reverse” surgical techniques of intervention for the correction of intestinal anatomy in the case of malabsorptive complications that cannot be corrected with pharmacotherapy.