Week 12 - Endocriology
Card Set Information
Week 12 - Endocriology
DM, Thyroid & Adrenals
Define Diabetes Mellitus [WHO 1999]
Metabolic disorder of multiple aetiology
Characterised by → chronic hyperglycemia & disturb of carb, fat & prot metabolism
Resulting from defects in insuling secretion, action or both
What are teh diagnostic criteria for DM?
Based on threshold values for micro-vascular disease
Symptoms + random BM >11.1mmol/l
Fasting Plasma Glucose >7mmol/l
2hours post oral GTT >11.1mmol/l
Define impaired glucose tolerance?
Fasting BM <7mmol/l
but post OGTT ~7.8-11.1mmol/l
Define Impaired fasting Glucose?
Fasting Glucose ~6.1-6.9mmol/l
Post OGTT <7.8mmol/l
Absolute insulin deficiency
no GLUT4 induction → hyperglycaemia
Outline the Pathology of T1DM
Autoimmune origin → pancreatic beta cell destruction
Outline the CF of T1DM?
PMH/ FH of autoimmune disease
rapid weigt loss
Polyuria & Polydipsia
What is Diabetic Ketoacidosis?
How does insulin deficiency lead to DKA?
DKA = Severe uncontrolled hyperglycaemia, acidosis & electrolyte imbalance
Lack of insulin leads to hyperglycaemia
^gluconeogenesis & glycogenolysis
Reduced peripheral uptake [no GLUT4]
Lack of insulin → ^ lipolysis
^^glycerol & FFA in portal circulation
FFA → ketone bodies [hepatic mitochondria] → ketosis & Acidosis
^^blood glucose → osmotic diuresis
loss of fluid & electrolytes [Na, K & Mg]
acidosis displaces intracellular K
Outline the Management of DKA?
Replace Insulin → 6u/hr, maintain BM 9-14mmol/l
Fluid replacement → FAST, 1l saline
Replace K → serum ^^, total body K = low
Supportive → ABCs, ECG, NGT, DVT-prophylaxis
What are the complications of T1DM?
Peripheral vascular disease
insulin resisitance + progressive insulin secretory defect
Give 5 RF for T2DM
Impaired glucose tolerance
Impaired flasting glucose
South asian or afro-carribean ethnicity
FH → genetic factors
For Metformin give;
Decr hepatic glucose production, decr GI glucose absorption, incr target cell insulin sensitivity
T2DM 1st line
Short half life
Take w meals
Stop during illness → lactic acidosis
For Sulphonylurea [Gliclazide] give
MoA → act on beta cells ^^release of insulin
Indications → intolerant to Metformin
A/E → weight gain, hypoglycaemia
PK/PD → short t1/2
WWJD? → dont take if pregnant/ lactating
For Thiazolidinediones [TZDs] such as Pioglitazone give
MoA → improves target cell resp to glucose, decr gluconeogenesis
Indications → 2nd line + SU
A/E → concerns re: safety, ^ankle swelling, ^risk of osteoporosis
PK/PD → prodrug, req hepatic metabolism
WWJD? → heart failure
Outline the Hypothalamic Pituitary Thyroid Axis?
Give 5 CF of Hypothyroidism & 2 causes?
Congenital → picked up on guthrie card
Post ablation → radio-iodine or surgery
Auto immune → hashimotos thyroiditis
What would the TFT results of a hypothyroid patient be?
What would the AntiTPO result be? Why?
^^TSH, low fT4/T3
Anti TPO in Hashimotos, cause of hypothyroid
What is the Tx for Hypothyroidism?
Converted to T3
What are the CF of thyrotoxicosis?
What are the causes of Thyrotoxicosis?
3 Ts of thyrotoxicosis
Also → weight loss, amenorrhoea, diarrhoea, moderate goitre w bruit
Autoimmune → graves disease [Stimulatory TSH-r Ab]
Thyroid Adenoma → goitre
^^TSH drive → Pituitary adenoma, hCG cross react w TSHr
What Ix would you perform for suspected Thyrotoxicosis?
TFTs → low TSH, ^^fT3/T4
TSH receptor antibody
Iodine uptake scan → radiolabelled iodine
How is Thyrotoxicosis treated?
Carbimazole → 40mg daily
Radioactive Iodine → thyroid destruction
What features of thyroid eye diseas are specific to Graves?
Graves eye disease
Lid lag & retraction are not specific to Graves.
How does Amiodarone cause hypothyroidism?
What would the O/E be?
Amiodarone has ^^Iodine
^^I → reactionary hypothyroidism
Thyroid just wants to chill
Outline the histology of the Adrenal Gland
Zona Glomerulosa → minerallocorticoids [Aldosterone]
Zona Fasciculata → Glucocorticoids [Cortisone]
Zona Reticularis → Androgens
Inner cortex → catecholamines
Outline the HPA axis?
What is Hyperaldosteronism?
Hyperaldosteronism = mineralocorticoid excess assoc w ^^BP & low K [arrythmia, muscle weakness]
→ suppressed renin levels
e.g. Conns syndrome, bilateral adrenal hyperplasia, adrenal carcinoma
→ to ^^^^^^renin
e.g. renal hypoperfusion [HF, cirrhosis, nephrotic syndrome]
How would you investigate Hyperaldosteronism?
U+Es → low K, ?renin [primary v secondary
Aldosterone renin ratio [raised = primary aldosteronism n.b ^^renin, ^^aldosterone]
Adrenal Vein sampling [to check for aldosterone]
MRI/CT → localise any adenoma
How is the hyperaldosternoid Pt managed?
Spironalactone [aldosterone antagonist]
Unilateral adrenalectomy [30% remain HBP]
What is hypoadreanilsim?
a.k.a Adrenal insufficiency
Inadequate production of steroid hormomes by adrenals
Usually Cortisol [may include aldosterone]
Primary acute → stress crisis/ rapid steroid withdrawal/ adreanl haemorrhage
Primary Chronic → Addisons/ MTB infection
Secondary → hypothalamic/ pituitary disease
What are the CF of Addisons Disease?
Hyperpigmentation of buccal mucosa & palmar creases [ACTH cross reaction w melanin receptors]
Vague symptoms [weightloss, dizzy fainting low mood diarrhoea etc]
'Unforgiving master of non-specificity & disguise'
How do you test for adrenal insufficiency?
Short ACTH test
Measure plasma [cortisol] befre & 30 mins after ACTH analogue has been given
Addisons excluded if 2n measure = >550mmol/l
What is Cushings Syndrome?
What are the differenct causes?
Cushings = glucocorticoid excess
ACTH dependant causes
Cushings Disease → pituitary adenoma secreting ACTH bilateral adrenal hyperplasia
Ectopic ACTH → Small cell lung cancer & carcinoid tumours
Ectopic CRH [Rare] → Prostate tumour
Iatrogenic → Steroid use
Adrenal nodular hyperplasia
What are the CF of Cushings Syndrome?
Peripheral muscle wasting
How do you investigate Cushings Syndrome?
Overnight Dexamethasone Suppression test
Give Pt steroid at midnight
measure cortisol before & at 8am
in healthy negative feedback so no ^cortisol
In CS → ^ cortisol despite low ACTH
What are the hormones secreted by the Anterior Pituitary?
Girls Like FAT!
Draw the control loop of Growth hormone release?
What is Acromegaly?
Give 5 CF of this disease!!!!!
Growth hormone excess [HODOR!]
Coarse facial features
spade like hands
Wrist pain → carpal tunnel