Diabetes mellitus

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Diabetes mellitus

Endocrine system


Diabetes mellitus


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USMLE® Step 1 questions

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High Yield Notes

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Diabetes mellitus

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USMLE® Step 1 style questions USMLE

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A 68-year-old man comes to the emergency department complaining of shortness of breath. One hour ago, while attending his nephew’s birthday party, the patient suddenly felt chest tightness with dizziness, and he was unable to catch his breath. Medical history includes type 2 diabetes mellitus, hypertension, chronic kidney disease, and chronic obstructive pulmonary disease. Medications include insulin, simvastatin, and lisinopril. He quit smoking 20 years ago. The patient’s temperature is 37.0°C (98.6°F), pulse is 190/min, respirations are 26/min, and blood pressure is 80/50 mmHg. Physical examination reveals the patient to be pale and in mild distress. Lung auscultation demonstrates clear breath sounds bilaterally. ECG shows the following:  

Reproduced from: Wikimedia Commons

Synchronized electrical cardioversion is attempted; however, the patient loses a pulse immediately afterwards. After 10 rounds of cardiopulmonary resuscitation, the patient is pronounced dead. Which of the following processes was the most likely contributor to this patient’s cause of death?  

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Atherosclerosis p. 302

diabetes mellitus and p. 346

β -blockers p. 246

diabetes and p. 246

Cataracts p. 535

diabetes mellitus and p. 346

Cerebrovascular disease

diabetes mellitus p. 346

Coronary artery disease

diabetes mellitus and p. 346

Diabetes mellitus p. 346-352

acanthosis nigricans p. 483

atherosclerosis and p. 302

atypical antipsychotics p. 573

β -blockers and p. 246

binge eating disorder p. 566

carpal tunnel syndrome p. 449

cataracts and p. 535

chronic renal failure and p. 603

CN III damage p. 541

diabetic ketoacidosis p. 350

diabetic retinopathy p. 537

endometrial cancer risk p. 648

Friedreich ataxia p. 531

fungal infections p. 186

glaucoma and p. 536

glucagonomas p. 350

glucosuria in p. 584

hemochromatosis p. 395

hepatitis C p. 173

hypertension and p. 301, 316

Klebsiella p. , 145

neonatal respiratory distress syndrome p. 661

nephropathy with p. 594, 595

neural tube defect association p. 491

opportunistic infections p. 153

pancreatic cancer p. 395

polyhydramnios and p. 642

preeclampsia and p. 643

in pregnancy p. 300

pyelonephritis and p. 600

readmissions with p. 272

renal papillary necrosis and p. 602

sexual dysfunction p. 567

tacrolimus and p. 120

teratogenic potential p. 614

type 1 vs type p. -19, 352

urinary incontinence with p. 599

urinary tract infections p. 181

UTIs and p. 600

Diabetes mellitus management p. 352-352

Diabetes mellitus type p. -20, 352

autoantibody p. 115

HLA subtypes with p. 100

Diabetes mellitus type p. -19, 352

amyloidosis p. 218

hyperosmolar hyperglycemia nonketotic syndrome p. 350

Diabetic glomerulonephropathy p. 595


diabetes mellitus p. 346

Glaucoma p. 536

diabetes mellitus and p. 346


diabetes mellitus p. 346

Growth hormone (GH) p. 334, 356

diabetes mellitus p. 346

Kimmelstiel-Wilson nodules

diabetes mellitus p. 346

Maternal diabetes

cardiac defect association p. 300

Myocardial infarction (MI) p. 304

diabetes mellitus p. 346


diabetes mellitus p. 346

Neural tube defects p. 491

maternal diabetes p. 614


diabetes mellitus p. 346

Polyuria p. 599

diabetes mellitus p. 346, 350

Pregnancy p. 633

Proteinuria p. 595

diabetes mellitus p. 346

Renal failure

diabetes mellitus p. 346


diabetes mellitus p. 346

Transposition of great vessels p. 298

maternal diabetes and p. 300

Weight loss

diabetes mellitus p. 346


In diabetes mellitus, your body has trouble moving glucose, which is a type of sugar, from your blood into your cells.

This leads to high levels of glucose in your blood and not enough of it in your cells, and remember that your cells need glucose as a source of energy, so not letting the glucose enter means that the cells starve for energy despite having glucose right on their doorstep.

In general, the body controls how much glucose is in the blood relative to how much gets into the cells with two hormones: insulin and glucagon.

Insulin is used to reduce blood glucose levels, and glucagon is used to increase blood glucose levels.

Both of these hormones are produced by clusters of cells in the pancreas called islets of Langerhans.

Insulin is secreted by beta cells in the center of the islets, and glucagon is secreted by alpha cells in the periphery of the islets.

Insulin reduces the amount of glucose in the blood by binding to insulin receptors embedded in the cell membrane of various insulin-responsive tissues like muscle cells and adipose tissue.

When activated, the insulin receptors cause vesicles containing glucose transporters that are inside the cell to fuse with the cell membrane, allowing glucose to be transported into the cell.

Glucagon does exactly the opposite, it raises the blood glucose levels by getting the liver to generate new molecules of glucose from other molecules and also break down glycogen into glucose so that it can all get dumped into the blood.

Diabetes mellitus is diagnosed when the blood glucose levels get too high, and this is seen among 10% of the world population.


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  2. "Harrison's Principles of Internal Medicine, Twentieth Edition (Vol.1 & Vol.2)" McGraw-Hill Education / Medical (2018)
  3. "Pathophysiology of Disease: An Introduction to Clinical Medicine 8E" McGraw-Hill Education / Medical (2018)
  4. "CURRENT Medical Diagnosis and Treatment 2020" McGraw-Hill Education / Medical (2019)
  5. "Harrison's Endocrinology, 4E" McGraw-Hill Education / Medical (2016)
  6. "Hyperglycemic Crises in Adult Patients With Diabetes" Diabetes Care (2009)
  7. "MECHANISMS IN ENDOCRINOLOGY: Seizures and type 1 diabetes mellitus: current state of knowledge" European Journal of Endocrinology (2012)

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