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Care of the Post-Bariatric Surgery patient: What I should know even if I am not a bariatric surgeon.


December 04, 2014

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Author: Samer Badr, MD

Objectives:

  • List the indications and contraindications of a bariatric surgery.
  • Describe the different types of bariatric surgeries and their specific most common medical and surgical complications.
  • Understand the specificities (clinical presentation and management) of a bariatric surgery patient admitted to the hospital

 

Why is this important?

  • > 1.5 million surgeries performed in US since 1992
  • Hospitalists and other non-bariatric surgery clinicians are often the first responders

 

Which patients are surgical candidates?

  • BMI > 40 Kg/m2
  • BMI 35-40 Kg/m2 + 1 serious comorbidity*
  • Controversial: BMI 30-35 Kg/m2 + serious comorbidity (ies), evidence lacking

    * Serious comorbidities: DM, HTN, hyperlipidemia, but also obstructive sleep apnea, asthma, poor quality of life...

 

Which patients are not surgical candidates?

  • Psychiatric diseases: bulimia nervosa/binge eating, untreated major depression, psychosis
  • Substance abuse: alcohol, drugs
  • Extremes of age (controversial): <18 years, >65 years
  • Prediction of future non-compliance (patient currently not compliant with physicals, Pap exam, medications, dietary restrictions etc).
  • Medical contraindication: cardiac, coagulopathy etc.

 

Bariatric surgical techniques in 2015:

  • Restrictive: Laparoscopic adjustable gastric band, Sleeve gastrectomy
  • Restrictive + Malabsorptive: Roux-en-Y gastric bypass, Biliopancreatic diversion with duodenal switch

 

Laparoscopic adjustable gastric band:

  • Tight adjustable band around the entrance of the stomach, creating a 20 ml gastric pouch
  • The least invasive, adjustable and reversible but the least effective
  • Complications: band slippage or infection, esophageal dilation, GERD

 

Sleeve gastrectomy:

  • Most of the stomach is removed, a sleeve remains to connect the esophagus to the duodenum
  • Complications: early (leak), late (stricture).

 

Roux-en-Y gastric bypass:

  • Most of the stomach is resected and a pouch is created. A jejunal limb (called Roux) is sutured to the gastric pouch and to the jejunum. Food bypasses the duodenum. 
  • Surgical Complications: early (leak; infection), late (stricture; obstruction; internal hernia). 

 

Biliopancreatic diversion with duodenal switch:

  • Ilium transected around 100 cm before the ileo-cecal valve and attached to the duodenum just distal to the pylorus.  Food then bypasses the duodenum, jejunum and the proximal ileum. A biliopancreatic limb is sutured to the ileum.
  • Most effective (most weight loss), procedure with the highest risk of complications.

 

A late surgical complication might present as a medical one:

  • Vomiting is less frequent post-bariatric surgery
  • Physical exam can be misleading due to altered anatomy
  • Naso-gastric tube will not decompress the exclude stomach and upper endoscopy will not visualize it

 

Medical complications:

  • Increased risk of gallstones. ERCP very difficult to perform due to altered anatomy.
  • Dumping syndrome (see case below)
  • Excessive weight loss due to anorexia, short bowel syndrome, bacterial overgrowth
  • Vitamin deficiency:  consider a banana bag if pt admitted with vomiting, to avoid Wernicke’s encephalopathy
  • Iron deficiency anemia: reduced gastric acidity that normally converts ingested ferrous (Fe2+) to the absorbable ferric (Fe3+)
  • Fracture, osteomalacia: check calcium and vitamin D before starting bisphosphonates.

 

Specific considerations for medications in a post-bariatric (malabsorptive) surgery patient:

  • Unpredictable post-op levels: antidepressants, oral contraceptives, immunosuppressive.
  • Avoid long acting (extended release) medications
  • Avoid medications requiring gastric acid (use calcium citrate instead of carbonate)
  • Anticipate a rapid improvement of DM and anticipate hypoglycemia

 

Case: John, 40 yo male admitted to the observation unit for hypoglycemia due to a sulfonylurea:

  • 40 yo male, 8 months post-Roux-en-Y, takes glipizide for DM type 2.
  • Comes to the ER with weakness, one hour after dinner, glucose is 40.
  • His sugars have been unpredictable with peaks and lows. Often after eating he has been feeling dizzy, bloated with abdominal cramps.

 

Discussion of the case:

  • Accurate diagnosis is dumping syndrome rather than glipizide induced hypoglycemia.
  • Pathophysiology: ingestion of large amounts of sugar à unregulated emptying by gastric pouch à osmotic fluid shifts (thus the GI symptoms) and hormonal surges (thus the hyper/hypoglycemia).

 

Clinical Pearls

  • In Laparoscopic Adjustable Gastric Band, esophageal dilation due to a tight band could mimic the appearance of achalasia on a barium swallow and is therefore named ‘pseudoachalasia syndrome’. It can also cause esophageal spasms giving the appearance of a Nutcracker esophagus on a barium swallow.
  • CT scan after Roux-en-Y requires oral contrast, in order to differentiate between the Roux and the excluded limb
  • Surgical exploration might be necessary to rule out post-op complications. Eg, A CT scan as well as an upper GI series can be read as normal and miss a post-Roux-en-Y internal hernia that would only be detected during surgical exploration.
  • The rapid improvement of the DM days after a Roux-en-Y is not due to weight loss but to hormonal changes (gut hormones such as peptide YY play an important role in glucose metabolism)
  • Ursodiol is often prescribed for 6 months post-op as it was shown to markedly reduce the risk of cholelithiasis.
  • Bacterial overgrowth is often due to decreased gastric acidity and narcotics that can slow the transit. Change in diet (less sugars and fiber, more fat) can help.

 

Take home points:

  • Hospitalist and PCP key player in (co)managing post bariatric surgery patients.
  • Clinical diagnoses might not follow the textbook: Low threshold for surgical involvement.

 

 Suggested reading: J Hosp Med. 2012 Feb;7(2):156-63. doi: 10.1002/jhm.939. Epub 2011 Nov 15.

 

 Bariatric Surgery Chart