1. Post-bariatric Surgery Hypoglycemia : A Descriptive Analysis
Rajasree Nambron, PGY2 Internal Medicine
Co-author: Daniel K Short, MD, PhD

2. Bariatric surgery for obesity- benefits
Bariatric surgery for morbid obesity- standard of care after failed medical therapy
Weight loss: 61%
HTN resolved: 62%
OSA resolved: 86%
Diabetes resolved: 77%
Hyperlipidemia improved: 70%

3. Bariatric surgery - complications
20%- adverse events
Early complications:
Bleeding, infections, PE and DVT
Late complications:
Metabolic and nutritional deficiencies
Dumping syndrome
Post-bariatric hypoglycemia
Failure to lose weight or weight gain

4. Possible causes of hypoglycemia after bariatric surgery
Medications: Hypoglycemic agents if still requiring after surgery
Dumping syndrome
Post-bariatric hypoglycemia syndrome (PBHS)

5. PBHS is defined as…
Spontaneous and symptomatic blood sugar less than 45 mg/dl in patients with history of gastric bypass
Inappropriately elevated insulin and C-peptide levels at the time of confirmed hypoglycemia
Exclusion of insulinoma
Exclusion of other causes of hypoglycemia (iatrogenic insulin or sulfonylurea use)
Subgroup of NIPHS (non insulinoma pancreatogenous hypoglycemia syndrome )
Presents 6 months to 8 years after bypass surgery with neuroglycopenic symptoms occurring 1-3 hours after eating.
Exact prevalence or treatment unclear at this time

6. PBHS Exact prevalence, incidence and treatment of PBHS is unknown
Presents 6 months to 8 years after bypass surgery with hypoglycemic or CNS symptoms occurring 1-3 hours after eating
Described 5 patients with neuroglycopenic symptoms, hyperinsulinemic hypoglycemia within 4 hours of meal ingestion
From endogenous source (not factitious)
FJ Service, et al, JCEM 84:

7. PBHS The mechanism of this process is unclear
GLP-1 (increases) and ghrelin (decreases) have both been implicated; but no proof
Not simply due to lack of regression of hyperplasia during obesity, since age/weight (pre-procedure) matched controls did not have islet hyperplasia

8. Pathology : in simple terms new islet cell formation!
FJ Service, et al, JCEM 84:

9. PBHS Treatment approaches tried:
Diet- small meals, avoid high carb diet
Acarbose and Nifedipine XR
Prednisone
Octreotide
Byetta
Reversal of procedure
Optimal treatment of the disorder is unknown.  Several approaches have been tried

10. Our Study
To estimate the prevalence of post-bariatric hypoglycemia syndrome in a large community academic center with a large bariatric surgery population
Characterize treatments given and their outcome

11. Methods Retrospective chart review
All patients who had bariatric surgery in last 10 years ( ) were included
Pre-screened for ‘hypoglycemia’ or symptoms of hypoglycemia

12. Inclusion Criteria: Significant Hypoglycemia
Random blood sugar < 60 mg/dl; AND
Exclusion of other known causes of hypoglycemia
Use of hypoglycemic agents (insulin or oral)
Adrenal insufficiency
Alcohol dependency

13. hypoglycemia syndrome
Results
N= 1092
Bariatric surgery patients ( ) ↓
N= 407 (37%)
Diagnosis of hypoglycemia or symptoms related to hypoglycemia ↓
N= 69(6.9%)
Significant Hypoglycemia (BG < 60 mg/dl) with no evidence of other causes ↙ ↘
Post-bariatric hypoglycemia syndrome ( N=5; 0.46%) as
BG < 45 mg/ dl
Symptomatic
C-peptide, insulin elevated
Other causes excluded
Imaging r/o insulinoma
Significant symptomatic hypoglycemia and possible Post-bariatric hypoglycemia ( N= 62)
C-peptide, insulin not measured !
D/D for this group other than PBHS : Dumping syndrome, insulinoma
N= 67(6.2%)
Symptomatic
N= 2 (0.18%)
Asymptomatic ↙ ↘
N= 6(0.55%)
Confirmed Post-bariatric
hypoglycemia syndrome
N= 61 (5.6%)
Unconfirmed (lack of data)

14. Characteristics of significant symptomatic hypoglycemia group

15. Therapy in significant symptomatic hypoglycemia group ( N=67)
Symptomatic hypoglycemia (N=67)
DIET COUNSELING (N=29;43%)
DID NOT REQUIRE ANY THERAPY (N=38; 57%)
Medications (N=4; 5.9%)
None required surgery

16. Therapy in significant symptomatic hypoglycemia group ( N=67)

17. Response to therapy in the PBHS group ( N=6)

18. Response to therapy in the PBHS group ( N=5)
Diet Counseling (N=6)
Successful Counseling 33.3% (N= 2)
Unsuccessful Counseling (66.6%N= 4)
Drugs
Prednisone (N=1)
Acarbose+Nifedipine XR N=2
Acarbose-1

19. Discussion Prevalence in our cohort: 0.46% (N=5) to 6.2% (N=67)
Diet counseling AND medications (acarbose, nifedipine XR, prednisone) can successfully treat this syndrome
More than 90% of patients with symptoms compatible with hypoglycemia following surgery not investigated completely
SYMPTOMS of hypoglycemia are common after surgery, but severe hypoglycemia requiring further workup was rare.  Since not all of those patients were worked up, it is possible that many more could have been diagnosed with PBHS if they had been evaluated further; however the fact that they did not require further evaluation makes the likelihood that those patients truly had PBHS fairly low.  If any of them DID have PBHS, it must have been fairly mild.  So it may be that our data reflects only severe PBHS.

20. Take away message.. Symptoms of hypoglycemia are common
after bariatric surgery (37%)
Confirmed symptomatic hypoglycemia-
uncommon
Post bariatric hypoglycemia syndrome is
very rare (0.46%), but an important
diagnosis/entity

21. Take away message.. Drug therapy + diet counseling successful
in improving symptoms in all cases
No patient required or desired surgery

22. ?