Approach to cushing syndrome dr vidyakar


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Approach to cushing syndrome dr vidyakar

  1. 1. Dr. Sachin Verma MD, FICM, FCCS, ICFC Fellowship in Intensive Care Medicine Infection Control Fellows CourseConsultant Internal Medicine and Critical Care Web:- Mob:- +91-7508677495
  2. 2. INVESTIGATION Hb 12.4 gm/dl,TLC 4100/mm3 Sr creat 0.9 mg/dl, RBS 98mg/dl S Na/K/Ca 140 /2.2/4.26 Sr ACTH=10.06 pg/ml LOW DOSE DST= 85 microgm/dl USG-WHOLE ABDOMEN: ?SOL in tail of pancreas ?SOL in lt adrenal gland,sol in liver,spleen and multiple lymphnodes.
  3. 3. Case presentationcushing syndrome
  4. 4. Approach to cushing syndrome In 1972 harvey cushings first described a 23 years old female with obesity, hirsutism and amenorrhea and 20 years later postulated that this “polyglandular syndrome” was due to primary pituitary abnormality causing adrenal hyperplasia. Traditionally, cushing syndrome is used to describe all causes. Cushing’s disease is reserved for cases of pituitaty dependent cushing’s syndrome.
  5. 5. Classification and etiology ofcushing syndromeACTH Dependent Cushing disease (pituitary dependent). Ectopic ACTH syndrome. Ectopic CRH syndrome Macronodular hyperplasia Iatrogenic (Treatment with ACTH).
  6. 6. Classification and etiology ofcushing syndromeACTH Independent Adrenal adenoma and carcinoma Primary pigmented nodular adrenal hyperplasia and carney’s complex. McCune albright syndrome Aberrant receptor expression Iatrogenic (Pharmacologic doses of prednisolone, dexamethasone)Pseudo-cushing’s Alcoholism Deposiiton Obesity
  7. 7. Symptoms of Excess Cortisol Truncal obesity Moon face Fat deposits supraclavicular fossa and posterior neck- buffalo hump HTN Hirsutism Amenorrhea or impotence Depression Thin skin Easy bruising Purplish abdominal striae Proximal muscle weakness Osteoporosis Diabetes Mellitus Avascular necrosis Wound healing impaired Pysch symptoms Hyperpigmentation Hypokalemic alkalosis
  8. 8. Investigation of a patient withcushing syndrome There are two stages in the investigation of a patient with cushing’s syndrome. Stage I - Does this patient have cushing syndrome? Stage II - If yes what is the cause? Note : Radiological investigations to be deferred until cushing’s syndorme has been confirmed biochemically.
  9. 9. Diagnosis Q1 Does this patient have cushing’s syndorme? Circadian rhythm of plasma cortisol. In normal subjetcs plasma cortical levels are highest in morning lowest at around midnight. This circadian rhythm is lost in cushing syndrome. – Midnight cortisol >7.5 µg/dl indicates cushing syndrome. – Sensitive test but due to many false positives not used .
  10. 10. Screening test Salivary cortisol – >2.0 ng/ml (5.5 nmol/L) – 100% sensitive – 96% specific Urinary free cortisol excretion – Normal : <220 to 330 nmol/24 hrs (80 to 120 µg/d) – Useful screening test Spot - Urinary cortisol - creatinine ratio – >25 nmol cortisol/mmol creat
  11. 11. Screening test(cont)Low dose/ overnight Dexamethasone suppression testProcedure:Oral adm of 1 mg dexamethasone previous night and next day 8.00 am plasma cortisol < 5µg /d is normal and < 2µg/day excludes cushings syndrome.0.5mg dexamethasone 6 hourly for 2 consecutive day and plasma cortisol at 48 hrs < 5µg/dl is normal <2µg/dl excludes cushing’s.
  12. 12. Low dose DST differentiates those who have cushing’s from those who donot have.
  13. 13. Screening testLoperamide test : To differentiate true cushing’s from pseudocushing’s lopermide lowers cortisol values in patients with pseudocushing’s but not in true cushing’s.Q.2 Haring confirmed cushing’s syndrome clinically and biochemically then go for the causative factor. Plasma ACTH: A Midnight ACTH > 5 pmol/L. (> 22pg/ml). In a patient with biochemical hypercortisolism confers that the underlying disease is ACTH dependant.Note : pts with bilateral MAH and Adrenal carcinoma /adenoma have variable levels.
  14. 14. Screening testPlasma potassium Hypokalemia alkalosis is present in more than 95% of patients with ectopic ACTH syndrome but is present in fever than 10% of patients with cushing’s disease.High dose dexamethasone suppression test 2 mg dexamethasone 6 hourly for 48 hours and greater than 50% decrease in urinary cortisol at 48 hours defines or positive response. Alternating 8 mg give at 11.00 pm plasma cortisol at 8.00 am next morning can be done. Note : 50% of patients with ectopic ACTH syndrome exhibit suppression and conversely patients with putuitary ACTH macroadenoma show no suppression.
  15. 15. High dose DST distinguish tose pts with cushing’s disease from those having ectopic ACTH syndrome/adrenal tumor
  17. 17. Metyrapone test Cholesterol ↓ Pregnenolone ↓ Progesterone  17OH-progesterone ↓ ↓ DOC11deoxy cortisol ↓ 11 beta OH ase ↓ Corticosterone cortisol ↓ Aldosterone Metyrapone 750 mg 4 hrly for 24 hrs.
  18. 18. Exaggerated rise in ACTH and 11 deoxycortisol val > 35µ/dl at 24 hours.Used to distinguish cushing’s disease from adrenal cause.Value of this test is questioned in modern endocrine practice due to more false positive result.
  19. 19. CRF TestPROCEDURE IV CRF 1 µg/kg (or) 100 µg bolous  measure plasma ACTH and cotisol every 15 mins for 1 to 2 hours.Results Normal  ACTH and cortisol increase by 15 to cushing disease  ACTH increase by 50%; Cortisol increase by 20% In ectopic ACTH syndrome  no response.
  20. 20. Inferior petrous sinus sampling Selective venous catheterisation Most robust test to distinguish cushing disease from ectopic ACTH syndrome is IPSS.Normal value Pituitary ACTH : Peripheral ACTH < 1.4 : 1 Cushing disease >2 Or Post CRF pituitary/peripheral ACTH >3 (97% sensitive, 100% specific)
  21. 21. Investigation algorithmScreening tests : – 24 hours urinary free cortisol (or) – 1 mg overnight DST Or – 11 PM midnight salivary cortisolConfirmation : – Low dose DST or – Midnight plasma cortisol
  22. 22. Defining the cause ACTH +high dose DST <50% suppression of UFC (or) plasma cortisol Suppression on high Fails to suppress on Fail to suppress on highdose DST and ↑ ACTH high dose + ↑ ACTH dose and ACTHCushing disease or Ectopic ACTH •Adrenal tumorbronchial carcinoid syndrome •Adrenal macro nodular hyperplasia CT chest/adrenal •Surreptitous use of MRI/CT of Pituitary glucocorticoids Pituitary tumor present No Pituitary mass CT of the adrenals Surgery Do CRH stimulation test IPSS with CRH  ectopic ACTH syndrome ↑ >50% ACTH Inconclusive ↑ 20% cortisol Cushing’s disease Repeat radiological studies
  23. 23. False PositivesSevere depressionSevere stressPhenytoin/phenobarbital/rifampin (accelerated metabolism of dex)Estrogen (pregnancy or OCP)Morbid obesity
  24. 24. Imaging Modalities Plain abdominal film Ultrasound (grey scale and Doppler)  CT scan MRI Adrenal scintigraphy 25
  25. 25. Plain Abdominal FilmPlain abdominal film finding are non specificMay be helpful in detecting Mass in adrenal area Calcification in adrenal 26
  26. 26. UltrasoundAdult appearance Entirely hypoechoic Concave with straight marginNewborn Cortex hypoechoic, Medulla hyperechoic Cortex>>medulla thickness Convex border 27
  27. 27. UltrasoundInvestigation of first choice in infant , children and pregnant womenIndication adrenal masses ( larger than 2 cm) 28
  28. 28. CT ScanOn precontrast scan adrenal have soft tissue density similar to that of liverNormal adrenal appear inverted V or Y shape within retroperitoneal fatConsist of body , medial limb and lateral limb 29
  29. 29. Ct ScanThickness of each limb is 5 mmMaximum width of the body is 10- 12mmIndication masses (adenoma & cancer) Cyst abscess metastasis 30
  30. 30. CT ScanAttenuation is measured in Hounsfield unit (HU)Benign masses have low attenuation values (< 20 HU )Malignant masses have high attenuation values (> 20 HU ) 31
  31. 31. CT ScanUnenhanced CT Scan Adenomas : < 10 HU Malignancies : > 20 HUDelayed enhanced CT Scan Adenoma : < 30 HU Malignancies : > 30 HU 32
  32. 32. MRIEqually effective as CT in imaging adrenal disorderNormal adrenal is intermediate signal intensity to liver and hypo intense to fat on TIW1 imageOn T2W2 image adrenal hypo intense to fat, iso intense to liver &hyper 33 intense to crus
  33. 33. MRICarcinoma have hyper-intense signal on T2W2 and hypointense on T1W1 imagesOn contrast enhancement show rapid enhancement with sluggish washoutAdenoma are hypointense, show mild enhancement & rapid 34 contrast washout
  34. 34. Adrenal scintigraphyUsual role of scintigraphy is to clarify inconclusive result of imagingIndication Functional status of adrenal nodule Assess contralateral adrenal function Detect functional metastasis Detect recurrence after surgery 35
  35. 35. Adrenal ScintigraphyAdrenocortical imaging agent NP-59 ( 6-B-iodomethyl-19- norcholesterol ) Selenium-75 6-B- selenomethylnorcholesterolSympathoadrenal imaging agent MIBG ( metaiodobenzylguanidine ) 36
  36. 36. Adrenal ScintigraphyIndication for MIBG Pheochromocytoma Neuroblastoma, carcinoid, adrenal metastasisIndication for NP-59 Adrenocortical carcinoma Adenoma Adrenal hyperplasia 37
  37. 37. MIBG Scintigraphy 38
  38. 38. MIBG Scintigraphy MIBG : Inc tracer accumulation in lt adrenal 39
  39. 39. TreatmentCushing’s Disease: Transphenoidal resection of pituitary adenomaAdrenal neoplasms: resectionEctopic ACTH: resection if possibleBilateral adrenal hyperplasia: may need adrenalectomies (lifelong glucocorticoid and mineralcorticoid replacement)
  40. 40. ‘Medical’ AdrenalectomyMedications that inhibit steroidogenesisKetoconazole (600 to 1200 mg/day)metyrapone (exacerbates female virilization) (2-3 g/day)Mitotane(2-3 G/day)- slow onsetAminoglutethinide (1g/day)Ocreotide can work in 1/3 of patients.Major side affect is adrenal insufficiency, therefore start at lowest dose and titrate
  41. 41. Complications of Cushings ifUntreatedDiabetesHTNOsteoporotic fractures and avascular necrosisInfectionsNephrolithiasisPsychosisDeath from vascular causes within 5yrs
  42. 42. PrognosisBenign adrenal adenoma- 95% 5 year survival, 90% 10 yearCushing’s disease (pituitary adenoma) same survival, but 10-20% transphenoidal resection failure rate over 10 years.Ectopic ACTH survival depends on malignancyUnknown cause of elevated ACTH- 65% 5 year survival, 55% 10 year survivalAdrenal carcinoma- median survival 7 months upto 2 yrs
  43. 43. THANK YOU 44