We provide a comprehensive analysis of individuals referred by their physician for evaluation of documented hypoglycemia (low blood sugar) for both diagnostic and treatment needs.

We have expertise in evaluation and management of complex hypoglycemia syndromes in adults, including insulin-producing tumors and hypoglycemia which follows gastrointestinal surgery (e.g. gastric bypass, sleeve gastrectomy, fundoplication, others).

You may receive opportunities to participate in specialized clinical trials.

Expert staffing comprised of our unique team of providers, including:

• Dr. Patti, an adult endocrinologist (hormone/metabolism specialist physician).

• Endocrinology fellow and experienced nurse practitioner who work with Dr. Patti

• A registered dietitian and certified diabetes educator with expertise in hypoglycemia.

• Registered nurses and certified diabetes educators.

How do I make an appointment?

We appreciate your interest in having an evaluation at the hypoglycemia clinic at Joslin. All individuals seeking an appointment must be referred by a physician (not self-referred) and a complete set of records from the referring physician must be received prior to scheduling an appointment. Additionally, if the referring physician is not an endocrinologist, but you have seen an endocrinologist in the past, these records will need to be received as well prior to scheduling your first visit. This is to ensure that the hypoglycemia team has all of information needed to carefully review your history prior to your appointment, as well as to inform what labs or testing may need to be ordered. Depending on appointment availability, it is possible that your first visit will be with an experienced nurse practitioner; this is to begin the process of evaluation, and you will see Dr. Patti at your next visit. After your initial visit, follow-up will be scheduled as needed.

We are experiencing high volume of referrals and have a long wait time until the appointment.  All information is reveiwed and those individuals with the most severe medical issues are prioritized.  If the wait time is too long, we would encourage you to seek care with your local endocrinologist who can also start the evaluation process. Following evaluation of your hypoglycemia you may be referred back to your endocrinologist for ongoing collaborative care to help implement the plan. To initiate the appointment process please call 617 309 2440 (appointments office).  

Resources

• Handout for physicians and other clinicians who may be seeing patients in an urgent care or emergency setting, describing strategies for managing acute aspects of hypoglycemia

• For additional information about results of ongoing research in this condition, please refer to PubMed search:  Patti ME - Search Results - PubMed (nih.gov)

Other thoughts about hypoglycemia that may be useful to you (May 2025):

HYPOGLYCEMIA IN GENERAL

Hypoglycemia is not your fault!

We recognize that hypoglycemia is challenging on so many levels.  

EVALUATION

The first step of evaluation is to verify that hypoglycemia is the cause of your symptoms.  Hypoglycemia causes a wide variety of symptoms - but these symptoms are not unique to hypoglycemia.  The symptoms can feel exactly the same as those with low blood pressure, rapid heart beat due to irregular heart rhythms, anxiety, or even symptoms related to how the stomach empties (sometimes called dumping syndrome) and others.

This is why it is essential that the evaluation done by your doctor is aimed at making sure that your symptoms are linked to low glucose at the time of the symptoms!

Continuous glucose monitors (CGM) are very helpful but are not accurate enough for making the diagnosis of hypoglycemia.  They are less accurate at low values.  In addition, they can give you falsely low readings.  For example, if you lay on the sensor during sleep, it can result in a falsely low glucose value.  The monitors are also less accurate in the first 24 hours after insertion of the sensor.  It is important to rely on a fingerstick glucose reading at these times to ensure accuracy.

CGM were designed for use in people with diabetes.  You may see that 70 is the lower limit of the CGM goal range.  Remember that this was designed for people with diabetes, many of whom are on insulin therapy. Keeping the glucose above 70 is helpful for safety in this situation.  However, people without diabetes often have glucose levels below 70 on CGM.  A sensor glucose value under 70 does not mean hypoglycemia.  Most healthy individuals do not have sensor glucose readings under 54 mg/dl.  

Once we verify that hypoglycemia is the cause of symptoms, additional evaluation may be done.  This is aimed at making sure you don't have medical conditions which would require different treatment plans  (e.g. insulin producing tumor, adrenal problem, others).  

We often do fasting testing to be sure your body can turn off insulin production when you fast.  Sometimes this could be an overnight fast or sometimes over several days in the hospital. We check other hormones such as adrenal hormones, to be sure these are not contributing.  

If the blood testing is normal this is a good thing!   It doesn't mean you don't have hypoglycemia.  It just means you don't have the other conditions which would be treated differently.  

INFORMATION ABOUT HYPOGLYCEMIA AFTER GASTROINTESTINAL SURGERY

Hypoglycemia can be a complication of upper gastrointestinal surgery, such as  gastric bypass, sleeve gastrectomy, gastrectomy, esophagectomy, or fundoplication.  After these surgeries, food enters the intestine quickly, and this causes the release of hormones and other signals which increase insulin production and then can cause hypoglycemia.  This is a well-recognized complication and not your fault!

INFORMATION ABOUT REACTIVE HYPOGLYCEMIA

Sometimes low blood gluoses can occur after eating, after activity, or at other times of the day.  Sometimes this is related to how your stomach and intestine moves (motility).  We do not fully understand all the causes but we and other research teams are working hard on this.  The evaluation is aimed at excluding  those causes of hypoglycemia which would be treated differently  (e.g. insulin producing tumor).  We often do fasting testing to be sure your body can turn off insulin production when you fast.  We check other hormones such as adrenal hormones, to be sure these are not contributing.  The first step of treatment focuses on changing nutrition to reduce the effect of food to stimulate insulin production and then lower glucose.  Sometimes we need to use medication in addition to medical nutrition therapy, if hypoglycemia is severe.

INFORMATION ABOUT POSTPRANDIAL SYNDROME

Sometimes people have symptoms similar to hypoglycemia after eating, but glucose levels remain normal.  It is thought that the symptoms relate to hormones and other signals released from the intestine after eating, which can cause symptoms.  The treatment is similar to hypoglycemia, and largely focuses on changing nutrition to lessen these symptoms.  It is a good thing if the glucose levels are normal!  We understand that you still have symptoms, but they just are not due to hypoglycemia. Other causes of similar symptoms can include rapid heart rate, low blood pressure, anxiety, and others.

TREATMENT

The first step of treatment focuses on changing nutrition to reduce the effect of food to stimulate insulin production and then lower glucose.  Sometimes we need to use medication in addition to medical nutrition therapy, if hypoglycemia is severe.  If you don't respond enough to changing food patterns, it is not your fault - everyone is different.  

We have a number of medications which we can choose from based on your specific condition and pattern.  If one medication does not work for you, we may need to use another medication or  combinations of medications.  Sometimes side effects can be present which cannot be predicted.

Continuous glucose monitoring can be helpful, especially for those persons who cannot always sense low glucose levels.  Suggestions for maximizing the benefits of CGM:

1.     When the sensor glucose is low:

• If you feel fine, check to be sure you are not laying on the sensor as this can cause a false low.  This is especially important during the first 12-24 hours after insertion of a new sensor, as this can cause a falsely low reading. When this happens, you need to check your glucose by fingerstick and meter to verify the reading.

• If you are having symptoms, try to test.  If you cannot, or have verified that the glucose is low, go ahead and treat.
  • Start with 2-3 glucose tablets (4 grams each) or 1/2 of glucose gel pack or gel pack mini size (e.g. Transcend).
  • Repeat after 15 minutes. Retreat if needed.
  • Follow the treatment with a snack containing protein and complex carbs (see handout).

2.  Be sure to discuss the alarms during your visit with your clinician.  Which ones are the ones you really need or pay attention to?

3.  The rapid fall alarm (3 mg/dl/min) can help you to PREVENT a low.  If you see this alarm, and the glucose is under 100, this is a signal to eat a small amount of food (e.g. piece of cheese, some nuts, natural sugar-free peanut butter)  to PREVENT subsequent hypoglycemia.  Don't wait for it to go low.

4.  Do not calibrate when sensor glucose is low, or when the arrow next to the circle with the glucose in the middle is either pointing up or down.  Just check the glucose by fingerstick but don't enter the # as a calibration.

Selected research publications on hypoglycemia authored by the staff of the hypoglycemia clinic - more in progress!  Thanks to our volunteers and funding from the NIH for making this progress possible!

• 2025:  Dr Patti and team reported that alterations in bile acid metabolism and transport were different in individuals with post-bariatric hypoglycemia, potentially paving the way for new approaches to treatment.  This was published in Nature Metabolism (PMID 40186075).

• 2024:  The Patti Lab team (working with both clinical and basic science team members) showed that serotonin and several aspects of glucose metabolism differ in individuals who develop hypoglycemia, as compared with those who do not develop hypoglycemia after gastrointestinal surgery.  This was published in Journal of Clinical Investigation (PMID:  39264731).

• 2024: The Patti Lab team reported on characteristics of individuals with hypoglycemia as compared with those without hypoglycemia. Key findings were high rates of irritable bowel, dumping syndrome, orthostatic hypotension, preoperative symptoms of hypoglycemia, and family history of hypoglycemia. This was published in Clinical Endocrinology (PMID: 39604085).

• 2024:  The Patti Lab reported on hypoglycemia associated with Ehlers-Danlos Syndrome.  This was published in JCEM Case Reports (PMID 39498469).

• 2023:  Dr. Patti reported results of treatment in a patient with  severe tumor-associated hypoglycemia, using an investigational antibody against the insulin receptor to block the effects of insulin.  This was published in the New England Journal of Medicine (PMID 37611129).

• 2023:  Dr. Patti and the hypoglycemia research team published results of the use of continuous glucose monitoring, which successfully reduced hypoglycemia and reduced glycemic variability.  This was published in Diabetes, Obesity, and Metabolism (Cummings C et al, PMID 37046360).

• 2023:  Scientific review of glucose metabolism after bariatric surgery:  implications for type 2 diabetes remission and hypoglycemia (Sandoval DA and Patti ME, Nature Reviews Endocrinology 2023, PMID 36289368).

• 2022:  Medical nutrition therapy and other approaches to management of post-bariatric hypoglycemia:  a team based approach (Patience N et al, Current Obesity Reports 2022, PMID 36074258).

• 2022:  Results of a study using pramlintide for post-bariatric hypoglycemia. Sheehan A et al, Diabetes Obesity and Metabolism 2022, PMID 35137513.

• 2022:  Review of hypoglycemia and dysautonomia (disorder of the autonomic nervous system) after bariatric surgery.  Addison P et al, Obesity Surgery 2022, PMID 35133603.

• 2021:  Identification of mediators of post-surgical diabetes control.  Dreyfuss JM et al, Nature Communications 2021, PMID 34845204.

• 2021:  Postbariatric hypoglycemia:  symptom patterns and associated risk factors in the Longitudinal Assessment of Bariatric Surgery study.  Fischer LE et al, Surgery for Obesity and Related Disorders (SOARD) 2021, PMID 34294589.

• 2020:  Review of post-bariatric hypoglycemia.  Sheehan A et al. Hypoglycemia After Upper Gastrointestinal Surgery: Clinical Approach to Assessment, Diagnosis, and Treatment, published in Diabetes, Metabolic Syndrome, and Obesity 2020, PMID 33239898. 

• 2018: review of  "Hypoglycemia after Gastric Bypass Surgery" .  Salehi M et al.  Journal of Clinical Endocrinology and Metabolism 2018, PMID 30101281. 

• 2017:  Our expert dietitian, Emmy Suhl RD, MS, summarizes the critical nutritional approaches to managing this condition. Suhl et al.  SOARD 2017, PMID 28392017. 

• Article from our hypoglycemia team which describes first steps to developing a glucagon delivery system to prevent hypoglycemia in this setting, information now guiding current ongoing research. Laguna Sanz AJ et al.  Diabetes Technol Ther 2018, PMID 39355439.

• Article from our hypoglycemia team about further development and testing of a novel glucagon delivery system to prevent hypoglycemia in patients with post-bariatric hypoglycemia.  This study is now guiding further development of a pump system.  Mulla CM et al.  Journal of Clinical Endocrinology and Metabolism 2020, PMID 31714583