কোন কোন condition এ আপনি OGTT করবেন না? করলে misinterpretation হতে পারে।

কোন কোন condition এ আপনি OGTT করবেন না? করলে misinterpretation হতে পারে। 🔴 An oral glucose tolerance test should not be performed in people, 📌 who are under physical stress - Post surgery - Trauma - Infection - Within 6 weeks of a myocardial infarction (MI) - Major surgery 📌 Drugs that may interfere with the test should be withdrawn for 3 days before the test if possible. - Glucocorticoids - Beta-blockers. - Thiazide - Loop diuretics Reference : Kumar & Clark, 11th e, 1212 আসুন, কেন এই situation গুলোতে করা যাবেনা সেটা নিয়ে বিস্তারিত কথা বলি ইনশা আল্লাহ। 🔴 Why should avoid OGTT during physical stress? Physical stress means infection, trauma, postoperative state, acute MI, major surgery. During significant physical stress, the body enters a counter-regulatory/hyperglycaemic state. 🔴During stress → ↑ catecholamines + cortisol + glucagon + growth hormone + inflammatory cytokines These produce: 📌 ↑ hepatic glycogenolysis 📌 ↑ hepatic gluconeogenesis 📌 ↓ peripheral glucose uptake 📌 ↑ insulin resistance 📌 Relative suppression of insulin secretion Thus these situations increase the average blood glucose level. Therefore, if you perform a 75 g OGTT during an acute infection or shortly after major surgery, the 2-hour glucose may be abnormally high even though the patient's usual glucose tolerance is not that poor. 🔷 Example A patient normally has: Fasting glucose = 5.5 mmol/L 2-h OGTT = 7.0 mmol/L 📌 During severe pneumonia: Fasting glucose = 6.8 mmol/L 2-h OGTT = 12 mmol/L The second result could reflect stress hyperglycaemia, rather than stable diabetes. Therefore, the test is postponed until the acute stress has resolved. 🔴 Why you should withdraw Glucocorticoids before OGTT? Glucocorticoids increases blood glucose level through: 📌 Glucocorticoids → ↑ hepatic gluconeogenesis 📌 ↓ Peripheral glucose uptake 📌 ↑ Insulin resistance Result in: ↑ plasma glucose So a patient taking glucocorticoids may develop a markedly abnormal OGTT despite having normal glucose tolerance without the drug. 📌 Glucocorticoid > ↑ transcription of gluconeogenic enzymes > ↑ hepatic glucose production. 📌 Glucocorticoid > ↓ GLUT4-mediated glucose uptake in muscle/adipose tissue > Insulin resistance Therefore: Glucocorticoids can cause a false-positive/overestimation of impaired glucose tolerance or diabetes on OGTT. 🔴 Why should we withdraw thiazide diuretics before OGTT? Thiazides can cause hyperglycaemia and impaired glucose tolerance particularly with prolonged use or higher doses. 📌 Thiazide → ↑ renal K⁺ loss > Hypokalaemia > Impaired pancreatic β-cell insulin secretion > ↓ Insulin level in blood > blood glucose level ↑ 📌 Thiazide also contributes to insulin resistance. So if someone is taking a thiazide during OGTT, their glucose may rise more than it otherwise would. 🔴 Note: Hypokalemia > ↓ insulin secretion from Beta cells. This is the reason why thiazide associated hyperglycemia is more common when potassium depletion is significant. 🔴 Why should we withdraw loop diuretics before OGTT? Loop diuretics can also promote glucose intolerance, although their effect is generally less central to routine diabetes diagnosis than glucocorticoids. They can cause: 📌 Loop diurtics > ↑ renal Na⁺/K⁺ loss > ↓ K⁺ > Potentially β-cell insulin secretion ↓ > higher glucose level. 📌 Loop diuretics may also produce metabolic changes associated with impaired glucose tolerance. 🔴 Why should we withdraw beta-blockers before OGTT? Chronic β-blocker therapy, particularly with some older/non-selective agents, may cause mild worsening of insulin sensitivity and glucose control, resulting in higher fasting/postprandial glucose in some patients. But this hypothesis is not established. 🎓Feel the MEDICINE Dr. Muhammad Mosleh Uddin www.mediversebd.com