Endocrine Flashcards
1
Q
Causes of Secondary HTN
A
Renal
Endocrine
2
Q
Endocrine causes of Secondary HTN
A
- Cushing
- Conn syndrome
- Hyperthyroidism / Hyperparathyroidism
- Acromegaly
- Phaeochromocytoma
3
Q
Phaeochromocytoma
A
Catecholamine producing tumour of adrenal medulla
4
Q
Symptoms of phaeochromocytoma
A
Sweating
Palpitation
Weight loss
HTN
5
Q
Ix for Phaeochromocytoma
A
I. 24 hour urine
- catecholamine levels or their metabolites (metanephrine)
- affected by drugs: eg. paracetamol, cough syrup, tricyclic antidepressant, beta blockers)
- sample needs to be collected in acid
II. Plasma metanephrine
- low specificity
- pts must be rested for 15-30 min
- affected by caffeine, alcohol, smoking
- only used as a secondary test
6
Q
Conn’s syndrome definition
A
Excess aldosterone production
Leads to alkalosis / hypokalaemia
7
Q
Causes of Conn’s syndrome
A
Primary - adrenal adenoma
Secondary - increased renin secretion
8
Q
Ix for Conn’s syndrome
A
Plasma aldosterone:renin ratio
Pt must be rested > 30 mins
Primary = High aldosterone + Low renin
9
Q
Secretions of anterior pituitary
A
TSH ACTH FSH LH GH Prolactin
10
Q
Acromegaly
A
Excess GH secretion
11
Q
Sx of Acromegaly
A
Sleep apnoea Protuding jaw HTN - Na retention Polyps Glucose intolerance Hypercalcaemia - increased Vit D
12
Q
Ix for acromegaly
A
Basal IGF-1 (and GH)
Glucose tolerance test - GH should be suppressed < 1
13
Q
Serum thyroid hormone forms
A
Bound > 99%
Free - active form
14
Q
Sx of hypothyroidism
A
- Lethargy, tiredness
- Weight gain
- Cold intolerance
- Coarsening of hair + skin
- Slow reflexes, hoarseness
- Constipation
- Menstrual abnormalities
- Bradycardia
15
Q
Mx of hypothyroidism
A
Thyroxin
16
Q
Hyperthyroidism symptoms
A
- Weight loss
- Heat inttolerance
- Palpitations
- Agitation, tremor
- Muscle weakness
- Diarrhoea
- Thyroid eye disease
- Menstrual abnormalities
17
Q
Hormones produced in adrenal gland
A
Adrenal cortex:
Aldosterone
Cortisol
Androgens
Adrenal medulla:
Catecholamines
18
Q
Layers of adrenal gland
A
Zona glomerulosa - aldosterone
Zona fasiculatis and reticularis - cortisol + androgens
19
Q
Daily cortisol production
A
25 mg/day
20
Q
Functions of cortisol
A
Insulin antagonist
Glucogenesis
Protein catabolism
Immunosuppressant
21
Q
Hypothalamo pituitary axis for cortisol release
A
CRH - Hypothalamus
ACTH - Anterior pituitary
Cortisol - Adrenal cortex
22
Q
Addison’s disease definition
A
Primary adrenal insufficiency
Reduced cortisol and aldosterone
23
Q
Sx of Addison’s disease
A
Hypoglycaemia
Hypotension
Hyperkalaemia
Skin hyperpigmentation
24
Q
Ix for Addison’s disease
A
High ACTH + Low Cortisol
Short Synacthen test
Electrolytes
25
Short Synacthen test
250 micrograms synthetic ACTH IM
| Normal people - cortisol rises > 420
26
Most common cause of Congenital Adrenal Hyperplasia (CAH)
21-hydroxylase deficiency
27
2 main types of CAH
Simple viralising
| Salt wasting
28
Simple viralising CAH
Androgen affected
| Male like symptoms
29
Salt wasting CAH
Aldosterone affected
30
Sx of Newborn CAH
- Ambiguous external genitalia
- Pigmented scrotum
- Salt wasting
- Sudden unexplained death (males)
31
Sx of Adult CAH
- Hirsutism
- Menstrual cycle disorder
- Subfertility
32
Ix for CAH
1) Blood:
17α hydroxy progesterone
Electrolytes
Glucose
2) Urine
- Electrolytes
- Steroid profile
33
Sx of Cushing's syndrome
```
Mental disturbances
Truncal obesity
Striae
Hyperandrogenism - hirsutism, amenorrhoea
Glucose tolerance
Sodium retention
HTN
Osteoporosis
```
34
Ix for Cushing's
Dexamethasone suppression test
| Low serum/salivary cortisol - false negatives
35
Dexamethasone suppression test
1) 1 mg overnight
9 am cortisal should be < 50 mmol/L
2) Low dose dexamethasone 6 hourly for 48 hrs
Cushing's shows no suppression
36
Cushing's disease
Pituitary dependent Cushing's syndrome
| ACTH is raised
37
Differentiating between primary and secondary Cushing's syndrome
High dose dexamethasone
Primary - no suppression
Secondary - some suppression
38
Causes of Diabetes Insipidus
Cranial
| Nephrogenic
39
Causes of Cranial Diabetes Insipidus
Idiopathic:
- Familial (autosomal dominant)
- Sporadic
Secondary:
- Trauma
- Tumours (craniopharyngioma, pituitary adenoma)
- Infections
- Autoimmune
40
Causes of Nephrogenic Diabetes Insipidus
Idiopathic
Secondary - drugs, metabolic, vascular
41
Drug causing Nephrogenic Diabetes Insipidus
Lithium
42
Vascular cause of Nephrogenic Diabetes Insipidus
Sickle cell disease
43
Metabolic cause of Nephrogenic Diabetes Insipidus
Hypercalcaemia
| Hypokalaemia
44
How does Hypercalcaemia lead to Hypernatraemia
calcium interfers with vasopressin action, if high can be the cause of water depletion/dehydration
45
Water deprivation test
Diagnoses Diabetes insipidus if urine osmolarity does not increase
46
Differentiating test for cranial vs nephrogenic diabetes insipidus
Desmopressin
47
Action of loop diuretics
Block Na reabsorption in proximal tubule
| Can cause hypokalaemia
48
Effect on acidosis on [K]
Acidosis leads to Hyperkalaemia
49
Actions of PTH
Bone resorption
Increases Ca reabsorption in kidney
Decreases PO4 reabsorption in kidney
50
Actions of 1,25dihydroxycholecalciferol
| Vit D
increased Ca and PO4 absorption from GI and Kidney
51
Actions of Calcitonin
Bone mineralisation
| Reduced Ca and PO4 reabsorption
52
Clinical use of calcitonin
Tumour marker
| Therapeutic Rx of hypercalcaemia and Paget's
53
Presentation of Hypercalcaemia
Bones, stones, abdo groans and psychic moans
```
Bone pain
Renal calculi
Constipation
Abdo pain
Confusion
```
54
ECG changes in hypercalcaemia
Shortened QT
| Bradycardia
55
Funky causes of hypercalcaemia
Prolonged tourniquet
Sarcoidosis
Thiazide diuretics - increased Ca reabsorption
56
Rx of hypercalcaemia
Rehydration
Bisphosphonates
Steroids - for malignant disease
57
Hypocalcaemia presentation
```
Lethargy
Tetany
Cramps
Cataracts
Brittle nails/hair
```
58
ECG changes in hypocalcaemia
Prolonged QT
| Arrhythmias
59
Hypocalcaemia treatment
Diet
Oral calcium supplementation
Oral vit D
IV calcium gluconate
60
Vit D deficiency in childern
Rickets
61
Vit D deficiency in adults
Osteomalacia
62
Causes of hypoparathyroidism
Surgery
Congenital - Di George syndrome
Mg deficiency - PTH resistance
63
Extracellular Ca distribution
50% free (ionised)
40% bound
10% complexed
64
Ovarian failure
Low oestradiol
65
Causes of primary ovarian failure
- Premature ovarian insufficiency
- Post menopausal
- Autoimmune damage
- Surgery
- Turners syndrome
66
Causes of secondary ovarian failure
LHRH deficiency - Kallman syndrome
| Prolactinoma
67
Physiological causes of hyperprolactinaemia
Pregnancy
| Drugs - dopamine antagonists
68
Role of dopamine on prolactin
Dopamine inhibits prolactin secretion
69
Pathological causes of hyperprolactinaemia
Prolactinoma
Acromegaly
Pituitary stalk lesions
Chronic renal failure
70
Presentation of Polycystic Ovarian syndrome (PCOS)
```
Oligo / Amenorrhoea
Obesity
Insulin resistance
Hirsutism
Oestrogenisation
Increased CVS risk
```
71
Endocrine levels in PCOS
High LH
| Normal FSH
72
Lab test changes during pregnancy
Increased:
- ALP
- GFR
Decreased:
- Albumin
- Creatinine
- Fasting BG
73
Hormone changes in pregnancy
Increased:
- Oestrogen
- Progesterone
- Prolactin
- hCG
Decreased:
- LH
- FSH
74
Complications of pregnancy
Gestational diabetes
HTN / Pre-eclampsia
Obstetric cholestasis
75
Pregnancy related liver diseases
```
Pre-eclampsia
HELLP
Hyperemesis Gravidarum
Acute Fatty Liver of pregnancy
Obstetric cholestasis
```
76
HELLP syndrome
Haemolysis
Elevated Liver enzymes
Low Platelets
77
Obstetric cholestasis
Usually 3rd trimester
| Generalised pruritis
78
Biochemistry findings of obstetric cholestasis
Serum bile acids
Raised ALT and AST
ALP and Bilirubin usually normal
79
Site of LH action
theca and
| mature granulosa cells
80
Site of FSH action
follicular
| granulosa cells
81
Phases of menstrual cycle
Follicular phase
| Luteal phase
82
Follicular phase of menstrual cycle
- Follicles recruited
- FSH makes it grow
- Oestrogen production
- Rise in oestrogen causes LH release
- LH ruptures follicle
83
Luteal phase of menstrual cycle
Corpus luteum carries on producing progesterone
84
Ix for infertility
```
LH/FSH
Prolactin
TFT
Testosterone
Oestradiol
```
85
Ovulation day in menstrual cycle
~ day 21
86
Assessment of ovulation
Progesterone level:
1) > 30 - normal ovulation
2) < 30 - reduced conception rate
3) low level, repeat next cycle
87
Role of FSH in males
stimulates sertoli cells to produce spermatozoa
88
Role of LH in males
stimulates Laydig cells to produce testosterone
89
Causes of male infertility
Hypergonadotrophic hypogonadism
Hypogonadotrophic hypogonadism
Obstructive azoospermia
90
Early signs of pre-eclampsia
HTN
| Raised urate
91
Late signs of pre-eclampsia
Raised urea and creatinine
Low GFR
Proteinuria
Oedema
