Challenges in Diagnosis and Management
Dr. Shadi Tabba Consultant Pediatric Endocrinologist Dubai Diabetes Center/ DHA Disclosures
I have no industry relations or conflicts of interest to disclose. Objec ves
Defining diabetes beyond age parameters
Understanding the special features of Type 1 vs. Type 2 vs. MODY vs. LADA vs. Flatbush Diabetes
Discussion on the overlap in presentation of the different types
Realizing the challenges in diagnosis and management of these types of diabetes Diabetes in History
1550 B.C., Egyptians describe a disease which shows as frequent urination and leads to emaciation
250 BC - 150 AD, Greeks describe a similar picture of “melting down of flesh and limbs” into the urine. They use the term “Diabetes” (siphon)
500 AD, 2 Indian physicians realizing presence of diabetes in youth and another type in obese adults, as did Avicenna who also describes DI
1675, English Doctor Thomas Willis adds the word Mellitus (sweet) to differentiate this condition from Diabetes Insipidus Diabetes in History
The diagnosis was generally considered a death sentence until Fred Banting and Charles Best try using insulin on a patient in 1922
Banting received Nobel Prize in 1923, made patent available for free
Banting is honored by naming World Diabetes day on his birthday (November 14th) every year
Mass production of insulin moves forward in addition to discovery of oral medications
Diabetes
Diabetes is a disorder of metabolism
It is signified by elevated blood glucose concentrations.
This is due to insufficient insulin effect, either due to insulin deficiency or due to insulin resistance and inefficient insulin function, or a combination of both.
DM Classifica ons: Age There was a time when:
Type 1 Diabetes was called “Juvenile Onset Diabetes”
And
Type 2 Diabetes was called “Adult Onset Diabetes” DM Classifica ons: Age Problem:
We have learned that Type 2 DM (Obesity+IR) happens in kids
We have learned that Type 1 DM (Autoimmune) may present in adults
We have learned of other forms of DM presenting at any age (MODY’s) DM Classifica ons: Treatment There was a time when:
Type 1 DM was called “Insulin Dependent Diabetes”
And
Type 2 DM was called “Non-Insulin Dependent Diabetes” DM Classifica ons: Treatment
Problem:
We’ve learned that Type 2 DM may become insulin-dependent
We’ve learned of other forms of DM which may or may not need insulin
We are looking into possible role for oral hypoglycemics in Type 1 DM
Type 1 Diabetes
Characterized by the body’s inability to produce insulin due to the autoimmune destruction of the beta cells of the pancreas.
The destruction has typically been there for several years (or decades) before reaching a point where the available active beta cells are insufficient.
May initially present with polyuria, polydipsia, nocturia, enuresis, weight loss, polyphagia, or even blurred vision and unusual candidal infections.
If initial symptoms are unnoticed or ignored, as insulin producibility continues to drop, ketosis and DKA may occur.
Type 1 Diabetes
Two peaks of incidence: From age 5-7 years and during puberty Antibodies are worth checking. They are by-products of the cellular immune response destroying the beta cells and are not the destroyers themselves. Antibodies: - IAA insulin autoantibodies - ICA islet cell antibodies - GAD-65 Glutamic Acid Decarboxylase antibodies - IA-2 (ICA-512) Tyrosine Phosphatase antibodies - Zn8 Transporter antibodies (recent) The more antibodies present, the higher the 5 year risk of diabetes 0: 0.2%, 1: 20%, 2: 50%, 3: 70%, 4:80%
Type 1 Diabetes
Atkinson et al., Lancet. 2001 Jul 21;358(9277):221-9 Adult Onset Autoimmune Diabetes
This umbrella of diabetics diagnosed in adulthood and found to have antibodies, covers a wide phenotype ranging from DKA to a mild non- insulin requiring diabetes. Commonest antibody is GAD-65
Prevalence of this is higher than childhood onset type 1 Diabetes
They seem to have a slower beta cell destruction process
Those requiring insulin right away may be labelled as adult onset type 1 Diabetes Mellitus. As for those who are not requiring insulin for 6 months after diagnosis, which is the higher chance: LADA Latent Autoimmune Diabetes of the Adult
Most prevalent form of autoimmune diabetes
They share genetic features with type 1 and type 2
Phenotypically, LADA is often misdiagnosed as type 2 diabetes
Why it matters that it’s LADA vs T2DM? LADA pts generally have worse HbA1c levels than type 2 diabetes pts
Clinically, LADA patients tend to have a lower mean age at diabetes onset, lower body mass index and more frequent need for insulin treatment than patients with type 2 diabetes.
Type 2 Diabetes
Characterized by resistance to insulin action (and excess Glucagon)
Typically, not dependent on insulin (but may require it)
More prone to have higher BMI, higher C-Peptide
To develop type 2 DM, there needs to be some degree of inadequate insulin secretion (inability to compensate for the insulin resistance)
There is proof of presence of beta cell dysfunction over time in type 2 Diabetics leading to possible need for insulin T1DM vs T2DM vs LADA Type 2 Diabetes vs Type 1 Diabetes
A person may be prone for/ develop autoimmune diabetes regardless of his weight and BMI and even presence of acanthosis. So an obese person can get type 1 Diabetes.
A person with type 2 Diabetes may present in DKA and be found to have low C-peptide at diagnosis (if it is a type 2 Diabetic this might recover). These tend to have less acidosis and faster recovery.
Once the acute incident resolves, many of them can recover beta cell function and go off of insulin (especially if aggresively treated initially).
C-Peptide level can be checked to confirm. Ketosis-Prone Diabetes Classification systems have been made for these patients to try to predict whether this patient presenting in DKA will truly be a type 1 Diabetes needing insulin, or a ketosis-prone type 2 diabetic (some have called this Flatbush Diabetes). It’s more common in non-whites.
These systems are: 1- ADA system looks mainly at those with complete Beta cell failure 2- Modified ADA as above with look at long term insulin requirement 3- BMI system (classifies into obese and lean) 4- Abeta system looks at autoantibodies and beta cell function
Balasubramanyam A. et al., Diabetes Care. 2006; 29(12): 2575 Ketosis-Prone Diabetes
The best classification system is the Abeta system:
- It looks at whether autoantibodies are there (A+ or A-)
- It assesses β cell function via Glucagon stim test at 2 weeks & 6 months after DKA or via fasting C-Peptide 2 weeks after DKA (β+ or β-)
- It has 99.4% sensitivity and 95.9% specificity.
Glucagon S m Test for C-Pep de
Glucagon 1 mg given IV to a fasting patient C-Peptide is measured before the injection and 10 minutes after it
Fasting C-Peptide >1.0 ng/dl and stimulated level >1.5 ng/dl is predictive of decent B cell function
There is good correlation with testing only fasting C-Peptide 2 weeks after presentation. Ketosis-Prone Diabetes
A- β- and A+ β- patients will typically act like type 1 Diabetes. Further studies are assessing how these 2 groups differ. Only 1% of them will ever recover β cell function long term. A+ of them may fit under LADA.
A+ β+ are only 5% of these patients. HLA testing can help predict whether they will progress to act like type 1 (they tend to). Need to monitor their β cell function over time even if insulin is stopped. These are 7% of adults presenting in DKA.
A- β+ act like type 2 Diabetes and will mostly not need insulin short term. This group is 74% of adults presenting with DKA. 70% will be insulin free by 10 weeks. Even 10 years later, 40% don’t need insulin.
MODY MODY (Maturity-Onset Diabetes of the Young), also called monogenic diabetes, is a term used to encompass a heterogeneous group of disorders with autosomal dominant inheritance leading to beta cell dysfunction leading to diabetes.
It is thought to account for 1-2% of diabetes , although this is probably an underestimate as it is underdiagnosed (misdiagnosed as T1 or T2)
Diagnosis may be important as some may be, at least for a while, treated with pills rather than insulin (and with better results).
It’s also important to diagnose so as to counsel the family. MODY Term first used in the 1970’s to describe some diabetics with mild form of it which was rampant in the family with autosomal dominant style of inheritance.
Genetic basis of it confirmed in the 90’s.
They used to be named as numbers (i.e. MODY 1, 2, 3, 4, etc.), but with the realization that they are truly different entities, there has been general agreement to name each condition based on the affected gene.
Tattersall RB. Q J Med. 1974;43(170):339–357
Yamagata K, et al. Nature. 1996;384(6608):458–460 MODY 3
MODY 2
MODY 1
MODY 5
MODY 10
MODY 4
MODY 6
MODY 8
MODY 9 MODY Screening Guidelines
These patients (typically under 25 years) have one or more of the following features:
1- Type 1 diabetic with: Family history of diabetes >50%, straight line (including gestational)** Absence of autoantibodies Insulin independence (beyond honeymoon period): witnessed by daily insulin doses less than 0.5 unit/kg/day, measurable C-Peptide when hyperglycemic, and absence of DKA if insulin is omitted.
2- Type 2 diabetic with the strong family history: Lack of features / causes for insulin resistance such as absence of obesity and acanthosis, or someone with normal/low TG and high HDL Ellard S, Bellanne-Chantelot C, Hattersley AT. Diabetologia. 2008;51(4):546–553 MODY
Some variants in genes involved may cause increased risk for actual type 2 Diabetes.
Extremely variable presentation and course makes it difficult to diagnose.
Expensive genetic testing. www.diabetesgenes.org there is a MODY probability calculator to say whether or not to test. Other supporting tests like the antibodies and Urine C-Peptide/Creatinine ratio.
Maybe someday all new diabetics will be tested? But even with the guidelines listed, yield for detection is low. Why pay the cost? Test if we find the special features discussed.