Diabetes mellitus

Changed by Daniel J Bell, 2 Jul 2022
Disclosures - updated 3 May 2022: Nothing to disclose

Updates to Article Attributes

Body was changed:

Diabetes mellitus (DM) often referred to simply as diabetes, is a group of metabolic conditions characterised by hyperglycaemia. 

These conditions should not be confused with diabetes insipidus which is clinically distinct and not related to hyperglycaemia.

Terminology

If a patient with diabetes mellitus requires insulin then this may be described as insulin-dependent diabetes mellitus (IDDM), conversely, if insulin is not required, then non-insulin-dependent diabetes mellitus (NIDDM). 

Clinical presentation

Symptoms/signs of hyperglycaemia classically include 1,2:

  • polyuria: frequent urination
  • polydipsia: increased thirst
  • polyphagia: excessive hunger
  • fatigue
  • weight loss (often masked by being overweight)

Other manifestations include:

  • diabetic dermopathy: e.g. granuloma annulare, necrobiosis lipoidica diabeticorum, eruptive xanthoma, and acanthosis nigricans 3
  • diabetic mastopathy (benign tumour-like breast masses)
  • manifestations of complications (see below)

Pathology

There are many forms of diabetes mellitus:

  • type 1 diabetes mellitus
    • the result of failure of pancreatic insulin production due to loss of beta cells in the pancreatic islets 1
    • the aetiology of this process is unknown but thought to be autoimmune 1
  • type 2 diabetes mellitus
    • the result of increasing insulin resistance, where the body's cells do not respond sufficiently to produced insulin 2
    • this is the most common form of diabetes mellitus (accounts for 90%) and is generally the result of obesity and occurs as part of the metabolic syndrome 2
  • type 3c diabetes mellitus
  • ​gestational diabetes
    • hyperglycaemia occurring in pregnant women without a prior history of diabetes 7
  • maturity onset diabetes of the young (MODY)
    • a rarer form of diabetes that is the result of one of a number of single-gene mutations causing defects in insulin production 8
    • there are a number of subtypes and these are generally inherited in an autosomal dominant manner 8
  • latent autoimmune diabetes of adults (LADA)
    • also known as diabetes mellitus 1.5 9
    • refers to the situation in which type 1 diabetes mellitus develops in adults 9
    • this may initially be mistaken for type 2 diabetes mellitus 9

Additionally, patients can be described as having 'prediabetes': a term used to describe the situation where an individual may have elevated glucose levels but does not reach diabetic diagnostic criteria. This includes the concepts of impaired fasting glucose and impaired glucose tolerance.

Diagnosis

The diagnosis of diabetes mellitus, generally, requires 1,2:

  • 2-hour glucose (glucose tolerance test) ≥11.1 mmol/L
  • fasting glucose ≥7.0 mmol/L
  • HbA1c ≥6.5% or ≥48 mmol/mol

In type 1 diabetes mellitus, for example, there are additional tests utilised to confirm the diagnosis, such as detection of autoantibodies (e.g. anti-GAD antibodies, anti-tyrosine phosphatase IA2 antibodies, anti-insulin antibodies) and C-peptide 1.

Radiographic features

The hyperglycaemia that characterises diabetes mellitus is clearly not radiographically visible but the complications of diabetes can often be detected radiologically, including (but not limited to) 10,11:

Furthermore, given the higher risk of infection seen in diabetes mellitus, these are also more likely to be seen radiographically in diabetic patients (e.g. osteomyelitisemphysematous pyelonephritis) 10

Treatment and prognosis

Treatment options vary depending on the type of diabetes, however, the following are the general options available 1,2,12:

  • lifestyle interventions
    • e.g. diabetes education, weight management, appropriate diet, aerobic exercise, cessation of smoking and alcoholism
    • these are generally indicated in patients with type 2 diabetes mellitus
  • antihyperglycaemic therapy
    • oral therapy (generally indicated in patients with type 2 diabetes mellitus)
      • biguanides (e.g. metformin)
      • sulfonylureas (e.g. gliclazide)
      • dipeptidyl peptidase-4 (DPP-4) inhibitors (e.g. linagliptin)
      • thiazolidinediones (e.g. pioglitazone)
      • sodium-glucose co-transporter 2 (SGLT2) inhibitor (e.g. dapagliflozin)
      • alpha-glucosidase inhibitor (e.g. acarbose)
    • insulin therapy (indicated in those with type 1 diabetes mellitus and in type 2 diabetes mellitus refractory to oral therapy)
      • many different forms (e.g. ultra-short acting, short-acting, long-acting, ultra-long-acting) and regimens
      • often used concurrently with oral therapy in patients with type 2 diabetes mellitus
    • glucagon-like peptide-1 (GLP-1) receptor analogues (e.g. exenatide), these medications are administered subcutaneously
  • bariatric surgery
Complications

Complications to the disease process can be either acute or chronic:

Furthermore, each therapy has its own potential set of complications, the most common and serious complication being hypoglycaemia.

  • -<li>peripheral neuropathy (e.g. glove and stocking distribution sensory changes, <a href="/articles/charcot-joint">Charcot arthropathy</a>, neuropathic pain, <a href="/articles/mononeuritis-multiplex">mononeuritis multiplex</a>, <a href="/articles/diabetic-amyotrophy">diabetic amyotrophy</a>)</li>
  • +<li>peripheral neuropathy (e.g. glove-and-stocking distribution sensory changes, <a href="/articles/charcot-joint">Charcot arthropathy</a>, neuropathic pain, <a href="/articles/mononeuritis-multiplex">mononeuritis multiplex</a>, <a href="/articles/diabetic-amyotrophy">diabetic amyotrophy</a>)</li>
  • -</ul><p>Furthermore, each therapy has its own potential set of complications, the most common and serious complication being hypoglycaemia.</p>
  • +</ul><p>Furthermore, each therapy has its own potential set of complications, the most common and serious complication being <a title="Hypoglycaemia" href="/articles/hypoglycaemia">hypoglycaemia</a>.</p>

References changed:

  • 1. Chatterjee S, Khunti K, Davies M. Type 2 Diabetes. Lancet. 2017;389(10085):2239-51. <a href="https://doi.org/10.1016/S0140-6736(17)30058-2">doi:10.1016/S0140-6736(17)30058-2</a> - <a href="https://www.ncbi.nlm.nih.gov/pubmed/28190580">Pubmed</a>
  • 2. Atkinson M, Eisenbarth G, Michels A. Type 1 Diabetes. Lancet. 2014;383(9911):69-82. <a href="https://doi.org/10.1016/S0140-6736(13)60591-7">doi:10.1016/S0140-6736(13)60591-7</a> - <a href="https://www.ncbi.nlm.nih.gov/pubmed/23890997">Pubmed</a>
  • 3. Lima A, Illing T, Schliemann S, Elsner P. Cutaneous Manifestations of Diabetes Mellitus: A Review. Am J Clin Dermatol. 2017;18(4):541-53. <a href="https://doi.org/10.1007/s40257-017-0275-z">doi:10.1007/s40257-017-0275-z</a> - <a href="https://www.ncbi.nlm.nih.gov/pubmed/28374407">Pubmed</a>
  • 4. Misra S & Oliver N. Diabetic Ketoacidosis in Adults. BMJ. 2015;351:h5660. <a href="https://doi.org/10.1136/bmj.h5660">doi:10.1136/bmj.h5660</a> - <a href="https://www.ncbi.nlm.nih.gov/pubmed/26510442">Pubmed</a>
  • 5. Pasquel F & Umpierrez G. Hyperosmolar Hyperglycemic State: A Historic Review of the Clinical Presentation, Diagnosis, and Treatment. Diabetes Care. 2014;37(11):3124-31. <a href="https://doi.org/10.2337/dc14-0984">doi:10.2337/dc14-0984</a> - <a href="https://www.ncbi.nlm.nih.gov/pubmed/25342831">Pubmed</a>
  • 6. Chawla A, Chawla R, Jaggi S. Microvasular and Macrovascular Complications in Diabetes Mellitus: Distinct or Continuum? Indian J Endocrinol Metab. 2016;20(4):546-51. <a href="https://doi.org/10.4103/2230-8210.183480">doi:10.4103/2230-8210.183480</a> - <a href="https://www.ncbi.nlm.nih.gov/pubmed/27366724">Pubmed</a>
  • 7. Kampmann U, Madsen L, Skajaa G, Iversen D, Moeller N, Ovesen P. Gestational Diabetes: A Clinical Update. World J Diabetes. 2015;6(8):1065-72. <a href="https://doi.org/10.4239/wjd.v6.i8.1065">doi:10.4239/wjd.v6.i8.1065</a> - <a href="https://www.ncbi.nlm.nih.gov/pubmed/26240703">Pubmed</a>
  • 8. Anık A, Çatlı G, Abacı A, Böber E. Maturity-Onset Diabetes of the Young (MODY): An Update. J Pediatr Endocrinol Metab. 2015;28(3-4):251-63. <a href="https://doi.org/10.1515/jpem-2014-0384">doi:10.1515/jpem-2014-0384</a> - <a href="https://www.ncbi.nlm.nih.gov/pubmed/25581748">Pubmed</a>
  • 9. Laugesen E, Østergaard J, Leslie R, Leslie R. Latent Autoimmune Diabetes of the Adult: Current Knowledge and Uncertainty. Diabet Med. 2015;32(7):843-52. <a href="https://doi.org/10.1111/dme.12700">doi:10.1111/dme.12700</a> - <a href="https://www.ncbi.nlm.nih.gov/pubmed/25601320">Pubmed</a>
  • 10. Chaudhary V, Bano S, Kalra S. Radiology and Diabetes Mellitus. J Pak Med Assoc. 2015;65(4):435-9. - <a href="https://www.ncbi.nlm.nih.gov/pubmed/25976585">Pubmed</a>
  • 11. Baker J, Demertzis J, Rhodes N, Wessell D, Rubin D. Diabetic Musculoskeletal Complications and Their Imaging Mimics. Radiographics. 2012;32(7):1959-74. <a href="https://doi.org/10.1148/rg.327125054">doi:10.1148/rg.327125054</a> - <a href="https://www.ncbi.nlm.nih.gov/pubmed/23150851">Pubmed</a>
  • 12. Chaudhury A, Duvoor C, Reddy Dendi V et al. Clinical Review of Antidiabetic Drugs: Implications for Type 2 Diabetes Mellitus Management. Front Endocrinol (Lausanne). 2017;8:6. <a href="https://doi.org/10.3389/fendo.2017.00006">doi:10.3389/fendo.2017.00006</a> - <a href="https://www.ncbi.nlm.nih.gov/pubmed/28167928">Pubmed</a>
  • 13. Hart P, Bellin M, Andersen D et al. Type 3c (Pancreatogenic) Diabetes Mellitus Secondary to Chronic Pancreatitis and Pancreatic Cancer. Lancet Gastroenterol Hepatol. 2016;1(3):226-37. <a href="https://doi.org/10.1016/S2468-1253(16)30106-6">doi:10.1016/S2468-1253(16)30106-6</a> - <a href="https://www.ncbi.nlm.nih.gov/pubmed/28404095">Pubmed</a>
  • 1. Chatterjee S, Khunti K, Davies MJ. Type 2 diabetes. (2017) Lancet (London, England). 389 (10085): 2239-2251. <a href="https://doi.org/10.1016/S0140-6736(17)30058-2">doi:10.1016/S0140-6736(17)30058-2</a> - <a href="https://www.ncbi.nlm.nih.gov/pubmed/28190580">Pubmed</a> <span class="ref_v4"></span>
  • 2. Atkinson MA, Eisenbarth GS, Michels AW. Type 1 diabetes. (2014) Lancet (London, England). 383 (9911): 69-82. <a href="https://doi.org/10.1016/S0140-6736(13)60591-7">doi:10.1016/S0140-6736(13)60591-7</a> - <a href="https://www.ncbi.nlm.nih.gov/pubmed/23890997">Pubmed</a> <span class="ref_v4"></span>
  • 3. Lima AL, Illing T, Schliemann S, Elsner P. Cutaneous Manifestations of Diabetes Mellitus: A Review. (2017) American journal of clinical dermatology. 18 (4): 541-553. <a href="https://doi.org/10.1007/s40257-017-0275-z">doi:10.1007/s40257-017-0275-z</a> - <a href="https://www.ncbi.nlm.nih.gov/pubmed/28374407">Pubmed</a> <span class="ref_v4"></span>
  • 4. Misra S, Oliver NS. Diabetic ketoacidosis in adults. (2015) BMJ (Clinical research ed.). 351: h5660. <a href="https://doi.org/10.1136/bmj.h5660">doi:10.1136/bmj.h5660</a> - <a href="https://www.ncbi.nlm.nih.gov/pubmed/26510442">Pubmed</a> <span class="ref_v4"></span>
  • 5. Pasquel FJ, Umpierrez GE. Hyperosmolar hyperglycemic state: a historic review of the clinical presentation, diagnosis, and treatment. (2014) Diabetes care. 37 (11): 3124-31. <a href="https://doi.org/10.2337/dc14-0984">doi:10.2337/dc14-0984</a> - <a href="https://www.ncbi.nlm.nih.gov/pubmed/25342831">Pubmed</a> <span class="ref_v4"></span>
  • 6. Chawla A, Chawla R, Jaggi S. Microvasular and macrovascular complications in diabetes mellitus: Distinct or continuum?. (2016) Indian journal of endocrinology and metabolism. 20 (4): 546-51. <a href="https://doi.org/10.4103/2230-8210.183480">doi:10.4103/2230-8210.183480</a> - <a href="https://www.ncbi.nlm.nih.gov/pubmed/27366724">Pubmed</a> <span class="ref_v4"></span>
  • 7. Kampmann U, Madsen LR, Skajaa GO, Iversen DS, Moeller N, Ovesen P. Gestational diabetes: A clinical update. (2015) World journal of diabetes. 6 (8): 1065-72. <a href="https://doi.org/10.4239/wjd.v6.i8.1065">doi:10.4239/wjd.v6.i8.1065</a> - <a href="https://www.ncbi.nlm.nih.gov/pubmed/26240703">Pubmed</a> <span class="ref_v4"></span>
  • 8. Anık A, Çatlı G, Abacı A, Böber E. Maturity-onset diabetes of the young (MODY): an update. (2015) Journal of pediatric endocrinology & metabolism : JPEM. 28 (3-4): 251-63. <a href="https://doi.org/10.1515/jpem-2014-0384">doi:10.1515/jpem-2014-0384</a> - <a href="https://www.ncbi.nlm.nih.gov/pubmed/25581748">Pubmed</a> <span class="ref_v4"></span>
  • 9. Laugesen E, Østergaard JA, Leslie RD. Latent autoimmune diabetes of the adult: current knowledge and uncertainty. (2015) Diabetic medicine : a journal of the British Diabetic Association. 32 (7): 843-52. <a href="https://doi.org/10.1111/dme.12700">doi:10.1111/dme.12700</a> - <a href="https://www.ncbi.nlm.nih.gov/pubmed/25601320">Pubmed</a> <span class="ref_v4"></span>
  • 10. Chaudhary V, Bano S, Kalra S. Radiology and diabetes mellitus. (2015) JPMA. The Journal of the Pakistan Medical Association. 65 (4): 435-9. <a href="https://www.ncbi.nlm.nih.gov/pubmed/25976585">Pubmed</a> <span class="ref_v4"></span>
  • 11. Baker JC, Demertzis JL, Rhodes NG, Wessell DE, Rubin DA. Diabetic musculoskeletal complications and their imaging mimics. (2012) Radiographics : a review publication of the Radiological Society of North America, Inc. 32 (7): 1959-74. <a href="https://doi.org/10.1148/rg.327125054">doi:10.1148/rg.327125054</a> - <a href="https://www.ncbi.nlm.nih.gov/pubmed/23150851">Pubmed</a> <span class="ref_v4"></span>
  • 12. Chaudhury A, Duvoor C, Reddy Dendi VS, Kraleti S, Chada A, Ravilla R, Marco A, Shekhawat NS, Montales MT, Kuriakose K, Sasapu A, Beebe A, Patil N, Musham CK, Lohani GP, Mirza W. Clinical Review of Antidiabetic Drugs: Implications for Type 2 Diabetes Mellitus Management. (2017) Frontiers in endocrinology. 8: 6. <a href="https://doi.org/10.3389/fendo.2017.00006">doi:10.3389/fendo.2017.00006</a> - <a href="https://www.ncbi.nlm.nih.gov/pubmed/28167928">Pubmed</a> <span class="ref_v4"></span>
  • 13. Hart PA, Bellin MD, Andersen DK, Bradley D, Cruz-Monserrate Z, Forsmark CE, Goodarzi MO, Habtezion A, Korc M, Kudva YC, Pandol SJ, Yadav D, Chari ST. Type 3c (pancreatogenic) diabetes mellitus secondary to chronic pancreatitis and pancreatic cancer. (2016) The lancet. Gastroenterology & hepatology. 1 (3): 226-237. <a href="https://doi.org/10.1016/S2468-1253(16)30106-6">doi:10.1016/S2468-1253(16)30106-6</a> - <a href="https://www.ncbi.nlm.nih.gov/pubmed/28404095">Pubmed</a> <span class="ref_v4"></span>

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