Endocrine 1 Flashcards
Adrenal cortex structure and function
Go Fetch Rex, Makes Good Sex
Zona Glomerulosa - Mineralocorticoids - ALDOSTERONE
Zona Fasciculata - Glucocorticoids - CORTISOL
Zona Reticularis - Sex hormones - Androgens - TESTOSTERONE
Renin
Secreted by juxtaglomerular cells
In response to low BP - SNS activation
Converts ANGIOTENSINOGEN to AT1
Angiotensin
AT1 converted to AT2 by ACE (from lungs)
Causes systemic vasoconstriction
Stimulates thirst centres in brain
Causes CV hypertrophy
Stimulates ZG to produce ALDOSTERONE
Aldosterone
Secreted by zona Glomerulosa
Acts on DCT and collecting ducts
Increases SODIUM reabsorption
Increases POTASSIUM excretion
ADH - Vasopressin
Secreted by PP - In response to low BP
Acts on collecting ducts
Increases water reabsorption
Hypervolaemic state
Hypertension
Cardiac distension
Raised AT2
Atrial myocytes secrete ANP
- Vasodilation
- Inhibits RENIN production
Addison’s aetiology
Primary adrenal insufficiency
Primary HYPOaldosteronism - AI
TB
Metastatic disease
HIV
Addison’s presentation
TTTT
Thin, Tanned, Tired, Tearful
N/V
Dizziness
Fatigue
Addison’s investigations
Bloods - U+E, FBC, serum CORTISOL
Short synACTHen test
- Give ACTH
- Should stimulate an increase in CORTISOL
- Will not happen in Addison’s
CT adrenals
Addison’s clinical findings
Low CORTISOL
- HYPOglycaemia
- HYPERpigmentation - Palmar creases, joints, buccal mucosa
Low ANDROGENS
Low BP
Low SODIUM
High POTASSIUM
Metabolic acidosis
Addison’s management
Replace Mineralocorticoids - FLUDROCORTISONE
Replace Glucocorticoids - HYDROCORTISONE
Vaccinations
Addison’s - Adrenal crisis precipitants
Infection
Missed medication
Stress
Surgery
Addison’s - Adrenal crisis presentation
Abdo pain
Cramps
Fatigue
Very low BP - Circulatory collapse
Metabolic acidosis
Addison’s - Adrenal crisis management
IV FLUDROCORTISONE
IV HYDROCORTISONE
Cushing’s aetiology
Gushing CORTISOL
ACTH dependent
- Pituitary tumour - Increased ACTH
- Ectopic - SCLC
ACTH independent
- Adrenal tumour
- Exogenous CORTISOL - Steroids
Cushing’s signs and symptoms
BBIIGGGG
Bone - Osteoporosis and fractures
Blood pressure ^^^
Infections
Irritability
GLUCOSE ^^^
Gynaecomastia
GnRH inhibition - Amenorrhoea
Gluconeogenesis
Cushing’s - Gluconeogenesis signs
Buffalo hump
Moon face
Diabetes
Central obesity
Muscle wasting
Abdominal striae
Thick skin
Bruising
Cushing’s investigations
24hr urinary free CORTISOL
ACTH levels - Low in ACTH independent
DEX suppression test - Low dose
- DEX will not suppress CORTISOL in Cushing’s
DEX - High dose
- Differentiate between pituitary and ectopic
- Suppression of Cortisol = Pituitary problem
- NO suppression of cortisol = Ectopic problem
MRI adrenals
CT pituitary and thorax (SCLC)
Cushing’s management
Treat cause
- Tumour excision
- Steroid reduction
KETOCONAZOLE and METYRAPONE
- Decrease CORTISOL production
Conn’s aetiology
Primary HYPERaldosteronism
Primary - Low RENIN
- Idiopathic
- Adenoma
Secondary - High RENIN
- Chronically low BP
- Cardiac failure
- Liver cirrhosis
Conn’s presentation
High ALDOSTERONE
High BP
High SODIUM
Low POTASSIUM
- Cramps
- Weakness
- Paraesthesia
Metabolic alkalosis
Conn’s investigations
ALDOSTERONE:RENIN ratio
Primary - High ALDOSTERONE and low RENIN
Secondary - High ALDOSTERONE and high RENIN
CT adrenals
Conn’s management
ALDOSTERONE antagonist - SPIRONOLACTONE
HYPERcalcaemia aetiology
METASTASES
MYELOMA
Granulomatous disease
TB/Sarcoidosis
HYPERthyroidism
HYPERparathyroidism
Dehydration
Addison’s
Drugs
- THIAZIDES
- LITHIUM
HYPERcalcaemia presentation
Bones - Bone pain Stones - Renal stones Groans - Abdominal pain Moans - Depression Thrones - Polydipsia, polyuria, constipation
Short QT
HYPERcalcaemia investigations and management
ECG - Short QT!
Calcium profile - Including vitamin D
HyperPTH screen
- PTH ^ - Should be LOW if Calcium ^
- Low phosphate
- Tech-99 scan - PTH gland
Skeletal survey
CXR - TB/sarcoid
Myeloma screen - Protein electrophoresis / ESR
Management
- IV fluids
- IV bisphosphonates
HYPOcalcaemia aetiology
Diet - Vitamin D deficiency
Malabsorption
HYPOparathyroidism - Secondary HYPERparathyroidism
Renal disease
Acute pancreatitis
HYPOcalcaemia presentation
Tetany - Chvostek sign Weakness Paraesthesia - Peri-oral Trosseau's sign- Abnormal hand posturing with BP cuff Long QT
HYPOcalcaemia investigations
Serum CALCIUM PTH U+E CRP Faecal calprotectin Anti-TTG
HYPOcalcaemia management
Calcium supplementation - ADCAL
IV CALCIUM GLUCONATE - Risk of tissue necrosis
Treat cause
Acromegaly aetiology
Abnormal GH secretion
Pituitary adenoma
Acromegaly presentation
Bitemporal hemianopia - Tunnel vision
Headaches
Dizziness
Greasy skin
Sweating
Large facial features
Large square hands
Large feet
Carpal tunnel
Diabetes
HTN
Acromegaly investigations
IGF-1
MRI pituitary
Acromegaly management
Somatostatin analogue - OCTREOTIDE
Transspenoidal tumour resection
HYPERkalaemia aetiology
Addison’s
Rhabdomyolysis
AKI
Metabolic acidosis
Drugs
- SPIRONOLACTONE
- ACE-I
- ARB
- HEPARIN
HYPERkalaemia presentation
Weakness
Fatigue
Flaccid paralysis
Decreased reflexes
HYPERkalaemia investigations
ECG - TTT
Tall Tented T waves Absent P waves Broad QRS Long PR Sinusoidal wave VT
HYPERkalaemia management
C BBIG, K DRop
CALCIUM GLUCONATE
- Cardiac membrane protection
- Only give if K > 6.5 or ECG signs
- Can cause tissue necrosis
Beta agonist - SALBUTAMOL Bicarbonates - SODIUM BICARBONATE INSULIN - Moves POTASSIUM back into cells GLUCOSE - DEXTROSE Diuretics - Eliminate POTASSIUM Renal dialysis
HYPOkalaemia aetiology
FUROSEMIDE
THIAZIDES
Conn’s
N/V
DKA management - INSULIN
HYPOkaelaemia presentation
Weakness
Hypotonia
Cramps
Paraesthesia
HYPOkalaemia investigations
ECG
Inverted T waves
Prolonged PR
U waves
ST depression
HYPOkalaemia management
Oral POTASSIUM - SANDOK
SIADH aetiology
Ectopic secretion - SCLC
Lung - TB, pneumonia
Brain - Meningitis, stroke, abscess
Drugs - Carbamazepine
SIADH pathophysiology
ADH made in hypothalamus Secreted by PP Binds to V2 receptors Increases number of aquaporin-2 channels in collecting tubule Leads to increased reabsorption of water
SIADH presentation
Irritability
Muscle cramps
Tremor
SIADH investigations
Low serum osmolality
High urine osmolality
Identify cause
- CT head
- CXR
SIADH management
SLOW TO AVOID CENTRAL PONTINE MYELINOLYSIS
Treat cause
Restrict fluids
HYPERTONIC SALINE
DEMECLOCYCLINE
Diabetes insipidus aetiology
Cranial
- Pituitary tumour
- Trauma
- Surgery
Nephrogenic
- CKD
- LITHIUM
- Low POTASSIUM
- High CALCIUM
Diabetes insipidus presentation
Low ADH
Polydipsia
Polyuria
Postural HYPOtension
Diabetes insipidus investigations
High serum osmolality
Low urine osmolality
DESMOPRESSIN stimulation test
- Cranial - Change in osmolality
- Nephrogenic - Unable to respond - No change in osmolality
Find cause - Imagine
Diabetes insipidus management
Cranial - DESMOPRESSIN
Nephrogenic - THIAZIDES + low salt diet
Treat cause
Pheochromocytoma aetiology
MEN-2
Malignant proliferation of chromaffin cells
Production of catecholamines
Pheochromocytoma presentation
TRIAD!
- Headaches
- Sweating
- Palpitations
HTN
Cafe au lait spots
Pheochromocytoma investigations
24hr Metanephrines
24hr catecholamines
MRI adrenal medulla
Pheochromocytoma management
ALPHA-BLOCKER
BETA-BLOCKER
Tumour resection
Thyroid structure and function
Hypothalamus secretes TRH
AP secretes TSH
Thyroid produces T3 and T4
T3 and T4…
- Regulate use of energy sources
- Protein synthesis
- Control body’s sensitivity to other hormones
Classification of thyroid disorders
HYPOthyroidism
- Primary - Problem affecting thyroid galnd
- Secondary - Problem with pituitary
- Congenital
HYPERthyroidism
- Primary
- Secondary < 1%
HYPOthyroidism aetiology
Hashimoto’s thyroiditis
- AI disease associated with DM1, Addison’s or pernicious anaemia
- Transient thyrotoxicosis in acute phase
Drugs
- LITHIUM
- AMOIDARONE
Subacute thyroiditis - de Quervain’s
- Associated with painful goitre and raised ESR
Iodine deficiency - Most common cause in developing world
HYPERthyroidism aetiology
Graves’ disease
- Most common cause of thyrotoxicosis
- May be associated with thyroid eye disease
Toxic multinodular goitre
- Autonomously functioning thyroid nodules that secrete excess thyroid hormones
Drugs - AMOIDARONE
HYPOthyroidism presentation
Weight gain
Lethargy
Cold intolerance
Dry cold yellow skin
Non-pitting oedema - Hands and face
Dry coarse scalp hair
Loss of lateral aspect of eyebrows
Constipation
Menorrhagia
Decreased deep tendon reflexes
Carpal tunnel syndrome
HYPERthyroidism s/s
Weight loss
Restlessness
Heat intolerance
Palpitations
Arrhythmias - AF?
Sweating
Pretibial myxoedema
Thydoid acropachy - Clubbing
Diarrhoea
Anxiety
Tremor
TFTs
Graves’ disease
Primary HYPOthyroidism
Secondary HYPOthyroidism
Graves’
- Low TSH
- High T4
Primary HYPOthyroidism
- High TSH
- Low T4
Secondary HYPOthyroidism
- Low TSH
- Low T4
Sick euthyroid syndrome
Low TSH
Low T4
Common in hospital inpatients
Changes reversible upon recovery from systemic illness
No treatment required
Subclinical hypothyroidism
High TSH
Normal T4
Patients on their way to developing HYPOthyroidism
Poor THYROXINE compliance
High TSH
Normal T4
Patients only taking THYROXINE in the days before a routine blood test
T4 normal but TSH lags - Reflects long-term low T4 levels
Thyroid disorders- Additional investigations
Autoantibodies
- Hashimoto’s - Anti-thyroid peroxidase (TPO)
- Graves’ - TSH receptor antibodies
- Thyroglobulin antibodies
Nuclear scintigraphy - Toxic multinodular goitre reveals patchy uptake
Thyroid disorder management
HYPOthyroidism - LEVOTHYROXINE
HYPERthyroidism
- Propranolol - Control symptoms
- CARBIMAZOLE
- Radioiodine treatment
HYPOnatraemia definitions
Normal SODIUM = 135-145
HYPOnatraemia < 135
Severe < 125
Acute < 48 hours
Chronic > 48 hours
HYPOnatraemia aetiology
EXCESS WATER
HYPOvolaemic
EUvolaemic
HYPERvolaemic
HYPOnatraemia presentation
Chronic - Asymptomatic
Acute moderate
- Headache
- Irritability
- N/V
- Confusion/delirium
- Unsteady gait
Acute severe
- Stupor/coma
- Convulsions
- Respiratory arrest
HYPOnatraemia - Effect on the brain
Low serum osmolality
Water moves into the brain causing swelling
Loss of SODIUM, POTASSIUM, CHLORINE, to compensate
HYPOnatraemia management
HYPER or EUvolaemic = Fluid restriction
HYPOvolaemic = SALINE replacement
