Endo Cram Flashcards
Adrenal cortex zones and products?
Zona Glomerulosa - produces aldosterone regulated by ECF concentration of K+ and angiotensin II
Zona Fasciculata - produces cortisol regulated by ACTH
Zona Reticularis - produces DHEAS -> androgens regulated by ACTH
Regulators and effects of mineralocorticoids?
Up-regulated by Angiotensin II (most powerful) and high K+
Down-regulated by atrial naturetic peptide
Increases Na channel in collecting duct
Increases Na and K+ excretion
Increases blood volume and blood pH
Regulators and effects of glucocorticoids?
ACTH stimulation produces cortisol
Highest on waking, lowest asleep
Increases gluconeogenesis and increases insulin resistance
Decreases B cells and lowers immune function
Increases bone resorption and lowers Ca = low BMD
Decreases fibroblasts (bruising, poor wound healing)
Increases adrenal androgens
Products of the adrenal medulla?
Dopamine
Norepinephrine
Epinephrine
Effects of Angiotensin II?
Vasoconstriction of efferent arterioles to increase resorption of sodium and water
Systemic vasoconstriction
Thirst
ADH release - water retention
Aldosterone release - sodium respiration and potassium excretion
Heart remodelling
Primary adrenal insufficiency
Deficiency of glucocorticoids and mineralocorticoids
Central adrenal insufficiency
Deficiency of glucocorticoids ONLY
Secondary - pituitary defect
Tertiary - hypothalamic
Low cortisol High ACTH Hypertension HypOnatremia & hypERkaelaemia High plasma renin
Primary adrenal insufficiency
Low cortisol
Low ACTH
Fasting hypoglycaemia
Secondary adrenal insufficiency
Synacthen test?
ACTH stimulation test
Normal in primary adrenal insufficiency
Low in secondary adrenal insufficiency
Low in tertiary adrenal insufficiency
Who to consider adrenal crisis in?
Primary adrenal insufficiency
Hypopituitarism
Previous or current prolonged steroid therapy
Presentation of adrenal crisis?
Hypotension & shock Hyponatremia Hyperkalaemia Hypoglycaemia Metabolic acidosis
Sign of primary adrenal failure?
Hyperpigmentation due to ACTH excess stimulating melanocortin1 receptor
Steroid replacement in adrenal crisis?
50-100mg/m2 IV hydrocortisone
If mineralocorticoid deficiency fludrocortisone can be started once oral intake is being tolerated
Causes of primary adrenal insufficiency?
CAH - infancy
Autoimmune - childhood
APECED - childhood
Adrenoleukodystrophy - childhood
Low cortisol High ACTH HypOnatremia/HypERkalaemia HIGH renin Hyperandrogenism - ambiguous genitalia in females
21-Hydroxylase deficiency
Autosomal recessive
CYP21A2
Ambiguous genitalia in females or increased penile length in boys
Hypertension
HypOkalemia
LOW renin
11B-Hydroxylase deficiency
CYP11B1
Ambiguous genitalia in males
Pubertal delay
Hypertension
17a-hydroxylase deficiency
CYP17A1
Weakness/spasticity
Blindness
Adrenoleukodystrophy
X-Linked
ABCD1
Craniofacial malformation
Growth failure
Developmental delay
Smith-Lemli-Opitz
Hypothalamic haemartoblastoma
Hypopituitarism
Imperforate anus
Gelastic seizures
Pallister-Hall
Non-classic 21-hydroxylase CAH presentation?
Premature pubarche
Advanced bone age
Cushing syndrome VS disease?
Syndrome = prolonged glucocorticoid excess Syndrome = pituitary adenoma secreting ACTH
Investigation findings in Cushing’s?
High midnight cortisol
High urinary cortisol
Elevated after low dose dexamethasone suppression test
Purpose of 2 step Dex suppression test?
Differentiate ACTH dependant or independant
Cortisol not suppressed if ACTH independant
Cortisol suppressed in pit adenoma
Causes of ACTH independant Cushing?
Iatrogenic
Adrenal adenoma
McCune-Albright/Primary Pigmented Nodular Adrenocortical Disease
HypERnatremia
HypOkalaemia
Hypertension
Low renin
Conn’s Syndrome
Primary Aldosteronism
Familial cancer syndromes associated w adrenocortical tumours?
Li Fraumeni (TP53)
Multiple Endocrine Neoplasia (MEN1)
Familial adenomatous polyposis (APC)
PRKAR1A gene
Headache
Sweating
Tachycardia
Phaeochromocytoma
- von Hippel-Lindau
- MEN2A MEN2B
- NF1
- TS
- Sturge Weber
- Ataxia Telangiectasia
Hormone production of alpha, beta and gamma pancreatic cells?
Alpha - secretes glucagon
Beta - secretes insulin
Gamma - secretes somatostatin
Earliest sign of beta cell dysfunction?
Loss of insulin secretion pulsatility
Diabetes clinically evident when 90% of beta cells lost
Site of action of glucagon?
Liver
Glucose maintenance mechanism in fasting periods?
2-4 hrs dietary glucose
Glycogenolysis stimulated by glucagon 10-12hrs
Gluconeogenesis stimulated by cortisol 12-24hrs
Lipolysis stimulated by GH 18-36hrs
Genes associated w T1DM?
85% NO FHx
HLA-DR3/4 and HLA-DQ2/8
Risk factors for T1DM?
Viral infections (40% congenital rubella)
Diet - BF protective, cows milk risk
High SES
Vit D def
Presentation of T1DM
Polyuria Polydipsia Weight loss Perineal canidiasis Visual disturbance (osmotic millieu of lens)
Antibodies assoc w T1DM?
Islet cell cytoplasmic antibodies - 70%
Anti-insulin antibodies - first apparent, disappear w insulin
Anti-GAD - 70-80%
Anti-IA2 - best predictor of T1DM development
Anti-zinc transporter - 99% specific
Autoimmune associations of T1DM?
Autoimmune thyroid disease 5% hypothyroid, 1% hyperthyroid
Celiac - increased risk if younger age of onset
Adrenal disease
Gastric autoimmunity
Vitiligo
Side effects of insulin?
Formation of antibodies Hypoglycaemia Insulin resistance Weight gain Local reaction Lipohypertrophy at injection site
Diabetic retinopathy screening and management?
1-2yearly from age 9/2yrs diabetic
Cotton-wool/soft exudates
Laser photocoagulation or photocoagulation
Diabetic nephropathy screening and management?
Annually from age 9/2yrs diabetic
Alb:Cr ratio
Improve BSL control, BP control, ACE-inhibitor, reduced protein diet
Diabetic neuropathy screening and management?
Annually from age 9/2yrs diabetic
Vibration/proprioception
Dwarfism
Delayed puberty
Hepatomegaly with steatosis
Cushingoid features
Mauriac Syndrome
Chronic underinsulinisation
DKA diagnostic criteria?
Hyperglycaemia
Metabolic acidosis (pH <7.3)
Ketonuria
Fluid and electrolyte replacement in DKA?
NS bolus if hypoperfused
NS + K+ for first 6hrs
Na will self-correct
K+ needs active replacement with correction of acidosis
BICARB NOT RECOMMENDED - paradoxical CNS acidosis
Risk factors for cerebral oedema?
1% of DKA presentations
1st presentation, long hx of poor control, age <5
Risk period is first 6-12 hrs after therapy initiation
-> treat w mannitol and fluid reduction
When to suspect T2DM?
Strong FHx
Obesity/central adiposity
Acanthosis nigricans, skin tags
No insulin requirement after honeymoon phase
Who to screen for T2DM?
Overweight PLUS - FHx - Hispanic/polynesian/indian/chinese - acanthosis/HTN/dyslipidaemia/PCOS SCreening test îs fasting plasma glucose
Most common presentation of T2DM?
Symptomatic - polyuria, polydipsia, fatigue
10% present in DKA; 10% hyperglycaemia hyperosmolar
Treatment of choice for T2DM?
Metformin monotherapy
Insulin if HbA1C >9%
SEs of metformin?
Abdo pain, diarrhoea, lactic acidosis
Assists in weight loss
Biguanide (metformin) mechanism?
Reduce hepatic glucose production
Reduce glucose uptake from stomach
Increase insulin sensitivity
Sulfonylureas (gliclazide) mechanism?
Increase insulin secretion from pancreatic beta-cells
Thiazolidinediones (-azones) mechanism?
Increase insulin sensitivity
Acarbose mechanism?
Reduce glucose absorption from GI tract
SLGT2 inhibitor (-pagliflozins) mechanism?
Promotes glycosuria reducing BGL
Hyperosmolar hyperglycaemia?
Severe hyperglycaemia without ketosis
Dehydration +++++
Needs more fluid Jesus than DKA, less insulin
Non-insulin dependant diabetes
Diagnosis <25
No auto-antibodies
Strong FHx (>2 generations)
MODY
Autosomal dominant
Treat w sulfonylureas
Most common MODY genes?
HNF1-alpha 50-65% (treat w sulfonylureas)
GCK 15-30% (treat w diet)
Which area of brain most susceptible to hypoglycaemia in neonatal period?
Occipital - visuospatial impairment
Determinants of growth in early childhood vs later childhood?
Genetic/chromosomal at all ages is most important factor
First 3 years of life - nutrition main driver, also IGF2
Later childhood growth hormone, nutrition, thyroid, vitamin D, steroids
Female vs male peak growth velocity?
Females 11-12
Males 13-14
Bone age normal range?
Up to 1yr/20% difference to chronological age considered normal
Conditions to consider if equal reduction in height and weight?
Chromosomal/TORCH
Conditions to consider if height more affected?
Endocrinopathies/skeletal dysplasia
Conditions to consider if weight more affected and HC normal?
Malnutrition
Precocious puberty in girls vs boys?
Girls = unlikely pathological Boys = brain tumour until otherwise proven
Delayed puberty in girls vs boys?
Girls = Turners until otherwise proven Boys = likely to be normal
Cause of short stature in Turners?
SHOX (short stature homeobox) insufficiency
Cause of short stature in renal failure?
IGF-1 deficiency
Renal disease = high GH and low/normal IGF-1
Features of constitutional growth delay?
Short child with normal height parents Slow growth Delayed puberty Delayed bone age Has good height prognosis
Features of familial short stature?
Child short and parents shirt
Normal growth and puberty
Normal bone age
Has poor height prognosis
Hypoglycaemia
Micropenis
Jaundice
Growth Hormone Deficiency
Causes of growth hormone deficiency?
GH1 mutation
Post-radiotherapy
Trauma
Infection (meningitis), inflammation, histiocytosis
Causes of growth hormone insensitivity?
GH Release Hormone mutation
GH Receptor mutation
IGF-1/IGF-1 receptor mutations
Complications/AEs of growth hormone replacement therapy?
Primary/central hypothyroidism T2DM Pseudotumour cerebrii Gynaecomastia SUFE Adenotonsillar hypertrophy/worsens OSA Possible link to leukaemia/brain tumours
Factors affecting onset of puberty?
Genetics
Increased BMI
Testosterone production?
Produced by Leydig cells and synthesised in tissues by 5-alpha reductase
In males FSH stimulates?
FSH stimulates Sertoli cells and results in spermatogenesis
In males LH stimulates?
LH stimulates Leydig cells and produces testosterone
In females FSH stimulates?
FSH stimulates follicular thecae cells and produces oestrogen/progesterone
When is greatest % of bone mass accrued?
Puberty - 50% of total bone mass
Hormone profile in central precocious puberty?
High LH and FSH (even post GnRH stimulation test)
High estradiol and testosterone
Hormone profile in combined central/peripheral precocious puberty?
Low then normal FSH and LH
High estradiol and testosterone
Hormone profile in peripheral precocious puberty?
Low LH/FSH
High estradiol and testosterone
Causes of central precocious puberty in girls?
Idiopathic (80%) Brain lesions - hypothalamic harmatoma or brain injury (radiation, hydrocephalus) Hypothyroidism NF1 MKRN3 - most common genetic cause
Precocious puberty and slow growth?
Hypothyroidism
Precocious puberty
Cafe au lait/coast of Maine lesion
Fibrous dysplasia
McCune Albright
Causes of peripheral precocious puberty in boys?
Hepatoblastoma
Germ cell tumours/gonadal or adrenal tumours
Solitary maxillary incisor
GH deficiency
Short stature
Frontal bossing, triangular face
Short incurved 5th fingers
SGA and FTT
Russell-Silver
Rapid growth in early childhood with no endocrine disorder found
Sotos Syndrome
TSHR antibody
Graves disease
Anti-Tg antibody
Autoimmune thyroiditis
Anti-TPO antibody
Autoimmune thyroiditis
Hypothyroidism
Absence of thyroid uptake on radio nucleotide scan?
Agenesis (most common)
Maternal thyroid blocking antibodies
Iodine trapping defect
Hypothyroidism
Increased thyroid uptake on radio nucleotide scan?
Dyshormonogenesis
Iodine exposure
Hyperthyroidism
Reduced thyroid uptake on radio nucleotide scan?
Exogenous T4
Subacute thyroiditis
Hashimoto’s
Hyperthyroidism
Increased thyroid uptake on radio nucleotide scan?
Graves
Multinodular/toxic nodule
Defect of thyroid binding globulin?
Not associated with clinical disease and requires no treatment
X-linked dominant
Congenital hypothyroidism causes?
85% thyroid dysgenesis
15% hereditary mutation of thyroid hormone synthesis
Hypothyroidism
Sensorineural deafness
Goitre
Temporal bone abnormality
Pendred syndrome
Most common cause of acquired hypothyroidism?
Hashimoto’s thyroiditis
Autoimmune acquired hypothyroidism causes?
Hashimoto's T21 Turner's T1DM Kleinefelter
Difference between transient hypothyroxinaemia and transient hypothyroidism?
Both affect press
Both have Low T4
Transient hypothyroxinaemia has a normal TSH but hypothyroidism has a high TSH
No need to treat hypothyroxinaemia, hypothyroidism needs treatment
Syndromes associated w Hashimoto’s?
APS1/2 IPEX Turner T21 Kleinefelter
Genes associated w increased risk of Graves?
HLA-B8 and HLA DR3
AEs of carbimazole?
Agranulocytosis ANCA vasculitis Pancreatitis Hepatotoxicity Cholestatic jaundice Lupus like syndrome Glomerulonephritis Teratogen
PTH actions?
Increased bone resorption within minutes
Increased intestinal absorption of calcium within days
Decreased urinary calcium excretion from distal tubule within minutes
Increased urinary phosphate excretion from proximal tubule
Anatomic locations in Vit D synthesis?
7-dehydroxycholesterol -> cholecalciferol in SKIN
Colecal -> 25OHD LIVER
25 OHD -> 1,25OHD KIDNEY
Hypocalcaemia and low PTH?
Hypoparathyroidism
HypoMg
Hypocalcaemia with normal PTH?
Abnormal calcium sensing receptor
Hypocalcaemia with high PTH?
Vit D deficiency
Pseudohypoparathyroidism
Renal failure
Hypocalcaemia
Hyperphosphataemia
High PTH
Pseudohypoparathyroidism
Causes of hypercalcaemia?
William's Syndrome Primary hyperparathyroidism Vit D excess Subcutaneous fat necrosis Renal disease
Medications that inhibit Vit D?
Glucocorticoids
Anti-epileptics
Anti-fungals
Anti-TB
Bone pain Muscle cramps Delayed dentition Delayed fontanelle colsure Bowed legs Hypocalcaemia
Rickets
Radiographic findings of rickets?
Best seen at growth plate of rapidly growing bones - ulna/knee Metaphyseal widening, fraying Osteopenia Fractures Trabecular bone
Phosphopenic rickets
Renal phosphate wasting - Fanconi
Hereditary
Presents with short stature and PROFOUND skeletal bowing
Posterior pituitary hormones?
ADH (vasopressin)
Oxytocin
46XY
Female genitalia
Complete androgen insensitivity
Anosmia
Delayed/absent puberty
Kallman
Learning disability
Tall, long legs
Mitral valve prolapse
Small testes, penis
Kleinefelter
47XXY
Bioavailability of sex hormone (oestrogen/testosterone) depends on what?
Level of sex hormone binding globulin
Cryptophthalmos
Ambiguous genitalia
Craniofacial anomalies
Fraser syndrome