Endocrinology Flashcards
What do alpha cells in the Islets of Langerhans secrete?and what is the function of that hormone?
Glucagon - breaks down glycogen into glucose
What do beta cells in the Islets of Langerhans secrete?
and what is the function of that hormone?
Insulin - increases glucose uptake and stores as glycogen in tissues
What happens with hormones in a post-prandial state (just after eating a meal)
Insulin production is increased to reduce blood glucose levels. In the liver- it stores glucose as glycogen and inhibits gluconeogeneis - so glucose isn’t produced.
What happens with hormones in a fasting state?
Insulin production is low and glucagon production is increased to release glucose from glycogen and lipolysis- breakdown of fatty acids to produce glucose
Give 4 causes of diabetes
Type 1 diabetes Type 2 diabetes Gestational diabetes MODY- maturity onset diabetes of the young- AD, diagnosed young, high genetic association Acromegaly Cushing's Steroids
What is the pathophysiology of type 1 diabetes
Autoimmune destruction of beta cells leading to insulin deficiency. This causes glucose production with no conversion to glycogen.
What are the symptoms of T1DM?
Polyuria (increased urinary glucose), polydipsia, weight loss, fatigue, hunger
What initial investigations are done for T1DM?
Random plasma glucose >11mmol Fasting plasma glucose >7 (on 2 occasions) 2 hour OGTT >11 HbA1c (for monitoring)- >48mmol may do urine dipstick for ketones
What is the first line treatment for T1DM?
Insulin
What is the first line insulin regime for T1DM?
Basal-bolus regime.
Long acting OD/BD + rapid acting before each meal
eg. lantus/levermir + novorapid
need to know how much carb eating to give correct bolus
What is second line insulin regime for T1DM?
Mixed insulin regime- mixed (containing rapid + short) + intermediate BD eg. Humulin I
What is the third line insulin regime for T1DM?
continuous insulin infusion
What are the monitoring requirements for both T1 and T2 DM?
HbA1c 3 monthly - target =48mmol
Eye and foot screening yearly
eGFR and urinary albumin: creatinine ratio yearly
What is the pathophysiology of T2DM?
Insulin resistance. so get decreased conversion of glucose to glycogen –> hyperglycaemia
What are the risk factors for T2DM
Central obesity, FMH, ethnic group eg. asians, lack of exercise, HTN
Initial investigations for T2DM?
Random plasma glucose >11 Fasting glucose >7 OGTT >11 HbA1c >48mmol (pre=diabetes: 42-47) U&Es (renal failure), lipids, LFTs (NAFLD)
What is first line treatment for T2DM?
Control RF- stop smoking, lose weight, exercise, statins, control BP
What is first line drug treatment for T2DM?
Metformin. SE: abdo pain/diarrhoea, lactic acidosis,
When would you start a second drug (in addition to metformin) in T2DM?
If the HbA1c > 58 despite the max dose of metformin
What second line drugs would be used in addition to metformin in T2DM?
Sulfonylureas - gliclazide SE: hypoglycaemia, weight gain
SGLT-2 inhibitors- gliflozins SE: UTI, genital thrush
Thiazolidinediones eg. pioglitozone- SE: weight gain, heart failure
DPP-4 inhibitors eg. sitagliptin. SE: few- GI discomfort
GLP-1 agonists eg. -tides SE: weight loss,
What is the associated dermatological condition with T2DM and why?
Acanthosis nigracans- dark hyper pigmented patches in folds of skin eg. groin, armpit, neck
What are the only 2 drugs allowed to treat diabetes in pregnancy?
Insulin and metformin. Discontinue all others.
What is the pathophysiology of DKA?
In absence of insulin to break down glucose- use free fatty acids are a source of energy which are broken down to ketones
The high levels of glucose cause lots of glucose to be excreted in kidney and water follows–> dehydrated
What is the triad of DKA?
Hyperglycaemia >11mmol or known DM
Ketones 2+ urinary, >3mmol blood
Acidosis ph<7.3 or bicarb <15
What are the signs and symptoms of DKA?
Polyuria, polydipsia, N&V, abdo pain. Signs= ketotic breath, Kussmaul breathing (deep laboured breathing to blow off CO2)
What investigations would you do for DKA?
Urine dip for ketones, blood ketones, blood glucose, FBC , U&E, CRP, ABG/VBG, infection screen- MSU, CXR?
What is the treatment for DKA?
- 1L 0.9% Normal Saline
- Fixed rate insulin at 0.1ml/kg/hour (prescribe 50 units Actrapid in 50ml saline). If glucose <14= add 5% dextrose.
Electrolytes: K 3.5-5.5= add 40mmol
A patient with known T2DM presents with significant dehydration (low BP, dry skin & mouth), leg cramps and weakness along with polyuria and polydipsia. Thinking of the likely diagnosis- what is the best initial investigation?
Blood glucose
Will be >30 if hyperosmolar hyperglycaemic state
What are some causes of HHS?
Infection, stroke, MI, hypo/hyperthermia
What is the pathophysiology of HHS?
Marked hyperglycaemia means the kidneys are unable to reabsorb it all so it spills out into the urine causing an osmotic diuresis- become dehydrated.
What are the investigations to with a patient presenting with HHS?
Blood glucose Ketones- absent Serum osmolality >320 Bloods- FBC, U&E- dehydration, LFTs, CRP, ABG/VBG- no acidosis Infection screen- CXR, urine sample
What is the treatment for HHS?
IV 1L 0.9% normal saline
Only give insulin if ketones raised or if glucose isnt dropping with saline alone.
Add 40mmol KCl if K 3.5-5.5
Patient is admitted with sweating, hunger, tachycardia, feeling drowsy. You manage to elicit from the history that he has taken excess of his diabetic medication. What initial investigation would you like to do?
Blood glucose. He is likely hypoglycaemic (blood glucose <3.9)
This patient has a decreased GCS, how would you treat his hypoglycaemia
IV glucose STAT (if no IV access= IM glucagon)
Then 1L 10% glucose 4-8 hourly and monitor glucose every 30 mins , keep it above 5
This patient has a normal GCS, how would you treat his hypogylcaemia?
15g quick acting carb eg. lucozade or 1 glycogel oral
If it is still low after 3 of these= IM glucagon or IV glucose
Once recovered: long acting carb= toast
What are the causes of hypoglycaemia?
Excess insulin/anti-diabetic drug in diabetic
Accidental dose in non-diabetic
Alcohol
Hypoglycaemia unawareness- lose the sympathetic drive after long time
Renal impairment
Describe the HPA (hypothalamus –> pituitary –> adrenal) axis
Hypothalamus –> CRH–> ACTH–> cortisol (negatively feedbacks)
What hormones do the adrenal cortex release from each zone? And from the medulla?
Cortex:
Zona glomerulosa: aldosterone
Zona fasiculata: cortisol
Zona reticularis: androgens
Medulla:
Adrenaline and noradrenaline
What are the causes of Cushing’s syndrome?
Exogenous- Oral steroids (ACTH independent- low )
Endogenous:
Cushing’s disease- Pituitary adenoma - ACTH dependent
Ectopic ACTH production (SCLC)- ACTH dependent
Adrenal adenoma- ACTH independent
Patient presents with moon face, scapular fat pad and. central obesity. Additionally- he struggles to stand up from the chair using his arms and legs. What condition does he have? And what other symptoms might he present with?
Cushing's syndrome. Other Symptoms include: Easy brushing, striae on skin He has proximal myopathy (protein breakdown by cortisol) Acne, hirsutism Recurrent infections
What ophthalmic/neuro sign would be found if pituitary adenoma was the cause of Cushing’s?
Bitemporal hemianopia
What is the first test done to diagnose Cushing’s?
24h urinary free cortisol
What is the diagnostic test for Cushing’s disease?
Dexamethasone suppression test. In Cushing’s disease and endogenous cause: cortisol will stay high (ACTH is driving production)
What would be found on 9am plasma ACTH if the patient had Cushing’s disease (pit adenoma) and ectopic ACTH or if he had adrenal adenoma
Cushing’s disease: 9am plasma ACTH will be high
Adrenal adenoma: low ACTH
What test would be used to would you differentiate between Cushing’s disease (pit adenoma) or ectopic ACTH secretion as the cause of Cushing’s syndrome
High dose dexamethasone
Cushing’s disease: serum cortisol will drop
ectopic ACRH: it will stay high
How would you image and treat Cushing’s disease?
Pit adenoma: MRI pituitary. Tx: surgical removal
How would you treat steroid induced Cushing’s syndrome?
Gradual decrease and stop steroids
What imaging and treatment would be done for ectopic ACTH production as cause?
CT chest, abdo, pelvis- looking for cancer (usually lung). Tx cancer.
A young person presents with intermittent headaches, sweating, palpitations. On taking the BP - it is 170/120. What is the likely diagnosis and its cause?
Phaechromacytoma.
Benign tumour of adrenal medulla - secreting adrenaline and noradrenaline
What is the first line investigation for phaechromacytoma?
24 hour plasma and urinary metanephrines. If this is +ve= CT abdo & pelvis
What is the treatment for phaechromacytoma?
Beta blockers (propranolol) then alpha blockers (phenoxybenzamine) Then surgical resection of the tumour
What is the pathophysiology of Addison’s disease?
Destruction of the adrenal cortex –> aldosterone and cortisol deficiency
What are the signs and symptoms of Addison’s disease?
Derm: Hyperpigmentation- mouth and palmar creases (excess ACTH)
MSK: Muscle weakness (proximal myopathy) , fatigue
GI: vomiting, abdo pain
Neuro: postural hypotension
What would be the electrolyte derangement in Addison’s disease? What would be the aldosterone and renin level change?
Decreased Na, raised Potassium (no aldosterone)
Decreased aldosterone, raised renin