Endo Flashcards
1
Q
How many adrenal glands are there in the human body?
A
Two adrenal glands.
2
Q
Where are the adrenal glands located?
A
In the retroperitoneum, superior to each kidney.
3
Q
What is the normal size of an adrenal gland?
A
5x3x1 cm.
4
Q
What are the distinct layers of the adrenal gland?
A
- Zona glomerulosa
- Zona fasciculata
- Zona reticularis
5
Q
What type of hormones are released from the zona glomerulosa?
A
Mineralocorticoids.
6
Q
What is an example of a glucocorticoid secreted by the adrenal gland?
A
Cortisol.
7
Q
What is the primary function of mineralocorticoids?
A
Regulate mineral balance.
8
Q
What hormones are produced by the adrenal medulla?
A
- Epinephrine
- Norepinephrine
- Androgens
9
Q
What stimulates the secretion of catecholamines from chromaffin cells?
A
Sympathetic stimulation via preganglionic fibers from T5-11.
10
Q
What is the role of cortisol in metabolism?
A
- Stimulating gluconeogenesis
- Glycogenolysis
- Protein catabolism
- Lipogenesis inhibition
11
Q
What is the function of aldosterone?
A
Reabsorbs sodium and water, secretes potassium.
12
Q
What is the main role of adrenal androgens?
A
Stimulate growth and development.
13
Q
What is the predominant neurotransmitter in the sympathetic nervous system?
A
Noradrenaline.
14
Q
True or False: The hypothalamus and anterior pituitary gland are connected via the hypophyseal-portal system.
A
True.
15
Q
What hormone does ACTH stimulate in the adrenal gland?
A
Glucocorticoid steroid hormones.
16
Q
What is the role of the pituitary gland?
A
Contains endocrine cells controlled by hypothalamic regulatory hormones.
17
Q
What is the shape of the thyroid gland?
A
Butterfly-shaped.
18
Q
What is the function of parafollicular C-cells in the thyroid gland?
A
Secrete calcitonin.
19
Q
What is thyroglobulin?
A
Precursor protein for T3 and T4.
20
Q
Fill in the blank: T4 has _______ iodine molecules and T3 has _______ iodine molecules.
A
four; three.
21
Q
What does TSH stand for?
A
Thyroid-stimulating hormone.
22
Q
What is the role of parathyroid hormone (PTH)?
A
Regulates serum calcium levels.
23
Q
What is the predominant type of bone in the human skeleton?
A
Cortical bone.
24
Q
What are the three major cell types in bone?
A
- Osteoblasts
- Osteoclasts
- Osteocytes
25
What is the primary function of osteoclasts?
Reabsorb bone.
26
What hormone increases osteoclast activity?
RANKL.
27
What is the primary role of calcitonin?
Inhibits osteoclast bone resorption.
28
What is the most biologically active form of vitamin D?
Calcitriol.
29
What condition is characterized by low serum calcium levels?
Hypocalcemia.
30
What is the function of FGF-23?
Controls renal handling of phosphate.
31
Where is insulin produced?
In beta cells within the Islets of Langerhans of the pancreas.
32
What is the effect of inhibiting osteoclast bone resorption?
Inhibiting osteoclast bone resorption leads to decreased bone loss.
33
What role does calcitonin play in the kidneys?
Calcitonin promotes calcium and phosphate excretion.
34
What is FGF-23?
FGF-23 is a hormone secreted by osteocytes that controls renal handling of phosphate.
35
What can stimulate massive release of FGF-23 in some patients?
Infusion of iron polymaltose can stimulate massive FGF-23 release.
36
What is insulin?
Insulin is a peptide hormone produced in beta cells within the Islets of Langerhans of the pancreas.
37
What is the process of insulin production?
Preproinsulin is cleaved into proinsulin, which is further cleaved in the Golgi apparatus to release C-peptide, leaving A and B chains linked by disulfide bonds.
38
How is insulin stored in the pancreas?
Insulin is stored in the inactive form as hexamers.
39
What triggers Phase 1 insulin release?
Phase 1 insulin release is triggered by increased blood glucose levels following a carbohydrate-rich meal.
40
What factors increase insulin release?
Factors that increase insulin release include:
* Hyperglycaemia
* Acetylcholine
* Sulfonylurea
* CCK
* GLP-1 and incretins
41
What are the physiological actions of insulin?
Physiological actions of insulin include:
* Glucose uptake into cells
* Decreased gluconeogenesis
* Glycogenesis and reduced glycogenolysis
* Lipid synthesis and reduced lipolysis
* Protein synthesis and reduced proteolysis
42
What is the epidemiology of Type 1 Diabetes Mellitus (T1DM)?
T1DM makes up <10% of diabetes diagnoses, affecting approximately 50 per 100,000 people in Australia.
43
What are the genetic associations with T1DM?
Genetic associations with T1DM include:
* HLA-DR3 and HLA-DR4 heterozygotes associated with predisposition
* HLA-DR2 offering protection
* Monozygotic twin risk of 40% for T1DM
44
What environmental factors are associated with T1DM?
Environmental factors may play a role, with viral infections like enterovirus, mumps, rubella, and coxsackie considered potential triggers.
45
What is the pathophysiology of T1DM?
T1DM is characterized by autoantibody destruction of beta cells in the Islets of Langerhans.
46
What is the common presentation of newly diagnosed T1DM?
Common presentations include polyuria, polydipsia, fatigue, weight loss, and diabetic ketoacidosis (DKA).
47
What criteria are used to diagnose diabetes mellitus?
Diagnosis can be based on:
* Fasting glucose on two occasions
* Random glucose with symptoms on two occasions
* Oral glucose tolerance test
* Glycated haemoglobin (HbA1c)
48
Which autoantibodies should be screened for at diagnosis of T1DM?
Autoantibodies to screen for include:
* Glutamic acid decarboxylase autoantibody (GAD)
* Proinsulin autoantibody
* Insulinoma-associated autoantibody (IA-2)
* Zinc transporter autoantibody (ZnT8)
49
What is the role of exogenous insulin in T1DM management?
Exogenous insulin acts as a direct replacement for endogenous insulin loss.
50
What is a basal-bolus regime in insulin therapy?
It consists of long-acting insulin (basal) for baseline needs and short-acting insulin (bolus) for meals.
51
What is diabetic ketoacidosis (DKA)?
DKA is an acute complication of T1DM occurring in the absence of sufficient insulin.
52
What are the common metabolic shifts in DKA?
Metabolism shifts from glucose to fatty acid metabolism, resulting in ketone production.
53
What are the key components of DKA treatment?
Key components include:
* Aggressive intravenous fluid resuscitation
* Intravenous insulin
* Aggressive potassium supplementation
54
What is the prevalence of microvascular complications in T1DM?
Microvascular complications include nephropathy, neuropathy, and retinopathy due to glycation of proteins.
55
What is the recommended screening for nephropathy in T1DM?
Annual screening for albuminuria should begin 5 years following a diagnosis of T1DM.
56
What is the significance of albuminuria in T1DM?
Albuminuria is an independent risk factor for end-stage renal failure and cardiovascular disease.
57
What are the typical symptoms of neuropathy in T1DM?
Symptoms include:
* Paraesthesiae
* Neuropathic pain
* Loss of proprioception
58
What is the most common sign of microvascular disease in T1DM?
Retinopathy is the most common and typically earliest sign of microvascular disease.
59
What is the pathogenesis of non-proliferative retinopathy?
Pathogenesis relates to blood vessel damage around the retina.
60
What are common organisms associated with enteric bacteria?
Pseudomonas, Enterobacter, Enterococcus
## Footnote
These organisms are commonly found in the intestines.
61
What type of examination is indicated annually for patients with T1DM?
Screening examination with proprioception and sensation testing
## Footnote
This is particularly important for patients with neuropathy.
62
What is the most common sign of microvascular disease?
Retinopathy
## Footnote
Annual ophthalmology screening is recommended for all patients.
63
What are the key findings in Non-Proliferative Retinopathy during fundoscopy?
* Microaneurysms
* Dilated venules
* Flame haemorrhages
* Cotton wool exudates
* Later macular oedema
## Footnote
This stage typically presents with little or no symptoms.
64
What causes Proliferative Retinopathy?
Lack of blood flow to areas of the retina from small vessel damage
## Footnote
This leads to neovascularisation around the retina.
65
What is the management for proliferative retinopathy?
* Laser photocoagulation
* Intravitreal Anti-VEGF (Bevacizumab) injections
## Footnote
These treatments aim to prevent vessel rupture and reduce neovascularisation.
66
What is a common complication of autonomic neuropathy in males with diabetes?
Erectile dysfunction
## Footnote
This is due to microangiopathy surrounding nerves necessary for erection.
67
What is the estimated prevalence of Type 2 Diabetes Mellitus (T2DM) in Australia?
55 per 1,000 people (approximately 1.8 million people)
## Footnote
T2DM is more common in developed countries.
68
What ethnic groups are at greater risk for developing T2DM?
* Pacific Islanders
* Indian
* Latin American groups
## Footnote
There is also a slight female predominance.
69
What is the most significant environmental risk factor for T2DM?
Diet
## Footnote
Obesity and sedentary lifestyle are strongly linked to T2DM.
70
What characterizes the pathophysiology of T2DM compared to T1DM?
Insulin resistance at peripheral tissues
## Footnote
T2DM often has sufficient insulin production early on.
71
What is the definition of MODY?
Maturity Onset Diabetes of the Young, a hereditary form of diabetes mellitus
## Footnote
Caused by single gene mutations inherited in an autosomal dominant pattern.
72
What are the screening recommendations for diabetes?
Not recommended for the entire population but for those with cardiovascular risk factors
## Footnote
Testing includes fasting glucose and oral glucose tolerance tests.
73
What lifestyle modifications can prevent T2DM?
* Education
* Dietary restrictions
* Exercise
## Footnote
These interventions are crucial for at-risk patients.
74
What pharmacotherapy is considered first-line for T2DM management?
Metformin
## Footnote
It is contraindicated in severe renal insufficiency.
75
What is the mechanism of action for Sulfonylureas?
Binds ATP-sensitive potassium channel at pancreatic beta cell surface
## Footnote
This action causes calcium influx and insulin secretion.
76
What are the side effects of Thiazolidinediones?
* Water retention/oedema
* Osteopenia
* Minor risk of bladder cancer
## Footnote
These medications have fallen out of favor due to cardiovascular risks.
77
What is the effect of Dipeptidyl Peptidase 4 Inhibitors (DPP-4) on HbA1c?
Can reduce HbA1c by 0.5-1.0%
## Footnote
They are weight neutral and have no risk of hypoglycaemia.
78
What is a significant post-marketing adverse effect of SGLT2 inhibitors?
Euglycaemic ketoacidosis
## Footnote
This can occur during fasting or stress if the medication is not withheld.
79
What distinguishes basal insulin from bolus insulin?
Basal insulin is long-acting, while bolus insulin is short-acting
## Footnote
Bolus insulin is used prior to carbohydrate ingestion.
80
What is the typical target HbA1c for diabetic patients?
<7.0%
## Footnote
The target may vary according to individual circumstances.
81
What is basal insulin?
Long-acting insulin with an expected duration of action of 24 hours
## Footnote
Basal insulin meets the baseline insulin requirement to allow glucose uptake in peripheral cells.
82
What are examples of long-acting insulin?
* Glargine (Lantus)
* Detemir (Levemir)
## Footnote
Long-acting insulin provides a low concentration of systemic insulin.
83
What is bolus insulin?
Short-acting insulin injected prior to carbohydrate ingestion
## Footnote
These injections account for high carbohydrate intake during meal times.
84
What is carbohydrate counting?
An effective method of estimating rapid-acting insulin doses
## Footnote
This method helps manage insulin dosage based on carbohydrate intake.
85
What are examples of rapid-acting insulin?
* Lispro (Humalog)
* Aspart (Novorapid)
* Glulisine (Apidra)
## Footnote
Lispro is the most rapid acting insulin.
86
What are mixed insulins?
Forms of mixed short-acting and long-acting insulin pens with differing ratios
## Footnote
Examples include 70/30 or 50/50 ratios.
87
True or False: Diabetic Ketoacidosis (DKA) is more commonly seen in T2DM compared with T1DM.
False
## Footnote
DKA is generally less commonly seen in T2DM.
88
What is Hyperosmolar Hyperglycaemic State (HHS)?
A condition caused by relative insulin deficiency, severe hyperglycaemia, and dehydration
## Footnote
It can occur during acute illnesses such as sepsis.
89
What are common symptoms of HHS?
* Coma
* Weakness
* Cramps
* Thirst
* Seizures
## Footnote
Severe hyperglycaemia leads to osmotic diuresis and dehydration.
90
What is the diagnosis criteria for HHS?
* Serum glucose level >30mmol/L
* Serum osmolality >320mOsm/kg
* pH <7.30
* Low levels of ketones <3mmol/L
* Dehydration
* Altered level of consciousness
## Footnote
Diagnosis depends on these laboratory findings.
91
What is the management for HHS?
Early, aggressive intravenous fluid resuscitation and insulin
## Footnote
Treatment of infections with intravenous antibiotics is also indicated.
92
What are macrovascular complications of T2DM?
* Coronary artery disease
* Cerebrovascular accidents
* Peripheral arterial disease
* Carotid artery stenosis
## Footnote
Long-standing T2DM is associated with these complications.
93
What is nephropathy?
Damage to the glomerular filtration barrier leading to albuminuria
## Footnote
Albuminuria is an independent risk factor for end-stage renal failure.
94
What should annual screening for albuminuria begin?
5 years following a diagnosis of T1DM
## Footnote
Screening should be performed using a spot test.
95
What is the definition of microalbuminuria?
30-300 mg of albumin in urine
## Footnote
Normal is <30 mg and >300 mg is macroalbuminuria.
96
What are the two types of retinopathy?
* Non-Proliferative Retinopathy
* Proliferative Retinopathy
## Footnote
Each type has distinct pathophysiological features.
97
What is the management for proliferative retinopathy?
* Laser photocoagulation
* Intravitreal Anti-VEGF (Bevacizumab) injections
## Footnote
These treatments aim to prevent vessel rupture.
98
What is autonomic neuropathy?
A complication of diabetes affecting autonomic functions
## Footnote
Common issues include erectile dysfunction and orthostatic hypotension.
99
What is the role of Leptin in obesity?
Inhibits NPY and stimulates POMC to reduce feeding and increase satiety
## Footnote
Leptin is produced in adipocytes.
100
What are the key types of bariatric surgery?
* Restrictive procedures (e.g., gastric banding)
* Bypass procedures (e.g., Roux-en-Y)
## Footnote
These procedures help reduce stomach size and food intake.
101
What is the most effective method of weight loss in obesity?
Bariatric surgery
## Footnote
It is considered the most effective method for sustainable weight loss.
102
What is the estimated prevalence of obesity in Australia?
30-35% of the adult population
## Footnote
Obesity is recognized as a global health pandemic.
103
What are the adverse effects of Phentermine?
* Cardiovascular effects (e.g., tachycardia)
* Neurological effects (e.g., seizures)
* Gastrointestinal effects (e.g., nausea)
## Footnote
Phentermine is a sympatheticomimetic drug.
104
What is the mechanism of action of GLP-1 agonists?
* Stimulate glucose-dependent insulin secretion
* Slow gastric emptying
* Inhibit glucagon release
* Reduce appetite
## Footnote
These actions contribute to weight loss and improved metabolic parameters.
105
What is Tirzepatide?
A glucose-dependent insulinotropic polypeptide and GLP-1 agonist
## Footnote
It produces a profound weight loss effect.
106
What is the role of lifestyle management in obesity?
Key for weight loss and should be attempted at diagnosis
## Footnote
Dietary energy restriction is crucial.
107
What is the Roux-en-Y bypass procedure known for?
Best sustainable weight loss outcomes, but increased surgical mortality and malabsorption syndromes
## Footnote
The Roux-en-Y bypass is a type of gastric bypass surgery.
108
What are the laparoscopic gastric banding procedures known for?
Safest procedures with respect to surgical mortality, provide good initial weight loss but may lead to weight reaccumulation later
## Footnote
These procedures involve placing a band around the stomach to limit food intake.
109
What are the five conditions that define Metabolic Syndrome?
* Increased waist circumference (Waist:hip ratio >0.90 for males, >0.85 for females)
* Hypertension (Blood pressure >140/90 mmHg)
* Dyslipidaemia (Triglycerides >1.7 mmol/L or HDL <1.0 mmol/L)
* Impaired glucose tolerance/insulin resistance or T2DM
* Increased hyperglycaemia
## Footnote
Metabolic Syndrome is a cluster of conditions that increase the risk of heart disease, stroke, and diabetes.
110
What is a common consequence of obesity related to joint health?
Joint damage, particularly in weight-bearing joints like hips and knees
## Footnote
Obesity is a leading cause for elective joint replacement surgeries.
111
What condition is characterized by hyperinsulinaemia leading to increased androgen levels in women?
Polycystic Ovarian Syndrome (PCOS)
## Footnote
PCOS can cause infertility, hirsutism, and acne.
112
What is the relationship between obesity and Gastrooesophageal Reflux Disease (GORD)?
Obese patients have increased rates of GORD due to increased intra-abdominal pressures
## Footnote
Increased rates of hiatus hernias and risks of Barrett's oesophagus are also noted.
113
What is Non-alcoholic fatty liver disease linked to?
Insulin resistance and can progress to cirrhosis
## Footnote
Hepatic steatosis is commonly seen in obese patients.
114
What is the leading cause of mortality in obese patients?
Cardiovascular disease
## Footnote
The development of metabolic syndrome further increases the risk of ischaemic heart disease and stroke.
115
What are common symptoms of a pituitary adenoma?
Headache and bitemporal hemianopia
## Footnote
Bitemporal hemianopia occurs due to compression of the optic chiasm.
116
What is the most common type of pituitary adenoma?
Lactotroph adenomas (prolactin secreting)
## Footnote
These account for approximately 50% of pituitary adenomas.
117
What is the gold standard test for diagnosing Diabetes Insipidus (DI)?
Fluid Deprivation Test
## Footnote
It distinguishes between central and nephrogenic DI.
118
What are the symptoms of Acromegaly?
* Enlarged hands and feet
* Macroglossia
* Enlargement of the jaw and forehead
* Skin tags
* Hoarse voice
* Hepatomegaly
## Footnote
Acromegaly involves excess growth hormone post puberty.
119
What is the primary treatment for Central Diabetes Insipidus?
Desmopressin
## Footnote
Desmopressin is a vasopressin analogue.
120
What is the role of IGF-1 in diagnosing Acromegaly?
Elevated levels of IGF-1 are diagnostic for acromegaly
## Footnote
IGF-1 levels are used for surveillance after surgery.
121
What are common causes of Panhypopituitarism?
* Non-functioning pituitary adenomas
* Craniopharyngiomas
* Meningiomas
* Metastatic deposits
* Pituitary apoplexy
* Infiltration (amyloid, sarcoid)
* Autoimmune hypophysitis
* Infection (meningitis)
## Footnote
These conditions can affect the secretion of hormones from the pituitary gland.
122
What is the role of omant in acromegaly?
Omant is a GH receptor antagonist that is very effective in acromegaly.
## Footnote
It is not currently funded on the PBS due to cost-effectiveness concerns.
123
What does GHRH stand for?
GHRH stands for Growth Hormone-Releasing Hormone.
124
What is the function of somatostatin?
Somatostatin inhibits the release of growth hormone (GH).
125
What type of receptor is GPCR?
GPCR stands for G-Protein Coupled Receptor.
126
What is an adenoma?
An adenoma is a benign tumor of glandular origin.
127
What does GH stand for?
GH stands for Growth Hormone.
128
What does GH-R refer to?
GH-R refers to Growth Hormone Receptor.
129
What is IGF-I?
IGF-I stands for Insulin-like Growth Factor 1.
130
What is the role of IGF-1 in the body?
IGF-1 is involved in cell proliferation and differentiation, linear growth, and glucose metabolism.
131
What surgical procedure may be required for a pituitary adenoma?
Surgical trans-sphenoidal resection of a pituitary adenoma may be required.
132
What is used for surveillance after surgery for acromegaly?
IGF-1 levels are used for surveillance after surgery.
133
What treatments are indicated for persistently elevated IGF-1 levels?
Treatment with somatostatin analogues or dopamine agonists is indicated.
134
What type of therapy can be used for recurrence of the pituitary adenoma following surgery?
Radiation therapy can be used for recurrence.
135
What long-term complications need screening and management in acromegaly?
Complications such as hypertension, dyslipidaemia, cardiovascular disease, and cancer screening are required.
136
What is Cushing's Syndrome?
A constellation of signs due to excessive cortisol production
137
What specifically causes Cushing's Disease?
Excessive ACTH production by an anterior pituitary adenoma or excessive CRH production by the hypothalamus
138
List three common symptoms of Cushing's Syndrome.
* Purple abdominal striae
* Proximal myopathy
* Obesity
139
What is a common cause of Cushing's Syndrome?
* Exogenous steroid administration
* Endogenous cortisol excess
* Cushing's Disease
140
What is the most sensitive and specific test for screening cortisol excess?
Midnight salivary cortisol
141
What indicates hypothalamic, pituitary, or ectopic ACTH production?
An elevated ACTH level
142
What is the gold standard investigation for identifying ACTH secretion origin?
Bilateral Inferior Petrosal Sinus Sampling
143
What is the first-line treatment for Cushing's Disease?
Trans-sphenoidal pituitary resection
144
What is Conn's Syndrome?
Primary hyperaldosteronism caused by a primary adrenal lesion
145
What are the classical signs of primary hyperaldosteronism?
* Systemic hypertension
* Mild hypokalaemia
146
What is the screening test for hyperaldosteronism?
Renin:aldosterone ratio
147
What is the treatment for a single adrenal adenoma in hyperaldosteronism?
Surgical adrenalectomy
148
What is the most common cause of primary adrenal insufficiency?
Autoimmune adrenalitis
149
What is an adrenal crisis?
Acute adrenal insufficiency that is a medical emergency
150
What is the first-line screening test for adrenal insufficiency?
Morning serum cortisol (0800hrs)
151
What is the gold standard for assessing adrenal insufficiency?
Insulin tolerance test
152
What should be given for treating Addisonian Crisis?
* Intravenous corticosteroid replacement
* Fludrocortisone if mineralocorticoid deficiency is suspected
153
What are phaeochromocytomas?
Neuroendocrine tumours of the chromaffin cells in the adrenal medulla
154
What is the most common symptom of phaeochromocytoma?
Episodic headache
155
What is the excellent screening test for phaeochromocytoma?
Plasma free metanephrines
156
What is the treatment for local disease in phaeochromocytoma?
Surgical resection
157
What percentage of adrenal incidentalomas are nonfunctioning adenomas?
70%
158
What is the recommended management for benign adrenal adenomas?
Surveillance CT if functional screening tests are negative
159
What is hyperthyroidism?
A condition characterized by excessive thyroid hormone production
160
List three common symptoms of hyperthyroidism.
* Tremor
* Irritability and anxiety
* Insomnia
161
What is the diagnosis of hyperthyroidism based on?
Low TSH and elevated T3 and T4
162
What is thyroid storm?
A rare but critical complication of hyperthyroidism requiring emergency management
163
What are common symptoms of hyperthyroidism?
Tremor, irritability, anxiety, insomnia, palpitations, diarrhoea, proximal muscle weakness, thin skin, weight loss
164
How is hyperthyroidism diagnosed?
By measuring a low TSH and elevated T3 and T4
165
What is a thyroid storm?
A rare but important complication of hyperthyroidism that requires emergency management
166
What symptoms are associated with thyroid storm?
Fever, tachycardia, diarrhoea, agitation
167
What treatment is required for thyroid storm?
Investigation of the cause, imaging of the thyroid gland, fluid resuscitation, antithyroid drugs, beta blockers, plasmapheresis
168
What are the two main antithyroid drugs used?
* Carbimazole * Propylthiouracil (PTU)
169
What is Grave's Disease?
An autoimmune disorder characterized by autoantibodies to the TSH-receptor
170
What are specific signs of Grave's Disease?
* Pretibial myxoedema * Grave's ophthalmopathy * Exophthalmos * Lid lag * Myopathy * Periorbital oedema
171
What is the primary cause of Grave's ophthalmopathy?
Abnormal connective tissue deposition in the orbit and extraocular muscles
172
What are the diagnostic indicators for Grave's Disease?
Low TSH, high T3/T4, autoantibody positivity to TSH-receptor antibodies
173
What imaging results are typical for Grave's Disease?
Tc-99 scans show global high uptake across the thyroid gland without nodules
174
What are the first-line treatments for Grave's Disease?
Antithyroid medications
175
What are the contraindications for carbimazole?
First trimester of pregnancy
176
What are the adverse effects of propylthiouracil?
* Liver failure * Agranulocytosis
177
What is the role of radioactive iodine in hyperthyroidism treatment?
It provides local beta and gamma radiation to the thyroid gland, destroying thyroid tissue
178
What are the contraindications for radioactive iodine treatment?
Pregnancy, Grave's ophthalmopathy
179
What is the typical outcome after radioactive iodine treatment?
Hypothyroidism requiring indefinite thyroxine treatment occurs in 80-90% of people
180
What is the preferred surgical option for hyperthyroidism?
Total thyroidectomy
181
What are common complications of thyroidectomy?
* Recurrent laryngeal nerve palsy * Hypoparathyroidism * Hypothyroidism
182
What treatment is required for severe Grave's ophthalmopathy?
* Lubricating eye drops * Corticosteroids * Optical decompression surgery if necessary
183
What is the prognosis for patients with Grave's Disease after treatment?
One in four will remain in remission, half will relapse, remainder may suffer hypothyroidism
184
What causes toxic multinodular goitre?
Functional autonomous thyroid nodules secrete excess T3 and T4 independent of TSH activity
185
What is the typical diagnosis for toxic multinodular goitre?
Low TSH and high T3/T4, autoantibody screen negative
186
What is the management for toxic multinodular goitre?
Radioactive iodine, antithyroid medications, thyroidectomy
187
What does thyroiditis refer to?
A broad group of conditions resulting in inflammation of the thyroid gland
188
What are common causes of thyroiditis?
* Autoimmune thyroiditis (e.g., Hashimoto's Disease) * Infection (viral) * Drug-induced * Postpartum thyroiditis
189
What are symptoms of hypothyroidism?
* Constipation * Weight gain * Cold intolerance * Cognitive decline * Alopecia * Bradycardia * Carpal tunnel syndrome
190
What is myxoedema coma?
A rare, life-threatening presentation of hypothyroidism characterized by hypothermia, hypoglycaemia, bradycardia, confusion, and coma
191
What are common causes of Hashimoto's Thyroiditis?
Autoantibodies to thyroid peroxidase (TPO), cytotoxic CD8 T-cell lymphocytes
192
How is Hashimoto's Thyroiditis diagnosed?
Elevated TSH, low T3/T4, anti-thyroid peroxidase antibodies present
193
What is the principal treatment for Hashimoto's Thyroiditis?
Thyroxine replacement
194
What is the most common cause of hypothyroidism worldwide?
Iodine deficiency
195
What is the diagnostic test for iodine deficiency?
14-hour urinary iodine collection after an oral iodine load
196
What can cause central hypothyroidism?
Loss of central release of TRH from the hypothalamus or TSH from the pituitary
197
What characterizes subclinical hypothyroidism?
Elevated serum TSH with normal T3 and T4 levels
198
What is the TI-RADS system?
A system for evaluating thyroid nodules based on composition, echogenicity, shape, margin, and echogenic foci
199
What features on ultrasound support malignancy in thyroid nodules?
* Hypoechoic lesion * Height greater than width * Irregular margins * Calcification * Increased vascularity
200
What is the general management approach for thyroid nodules?
Thyroid function testing, ultrasound, fine-needle aspiration (FNA) based on size and features
201
What is the definition of hyperechoic?
Hyperechoic refers to tissues that reflect more ultrasound waves than surrounding tissues, appearing brighter on ultrasound imaging
202
What does hypoechoic mean?
Hypoechoic refers to tissues that reflect fewer ultrasound waves than surrounding tissues, appearing darker on ultrasound imaging
203
What is a very hypoechoic tissue?
Very hypoechoic tissue appears significantly darker on ultrasound compared to surrounding tissues
204
What are the ultrasound characteristics of a benign thyroid nodule?
Benign thyroid nodules are typically wider than tall, smooth, and well-defined
205
What are the ultrasound features that raise suspicion for thyroid malignancy?
Features include taller-than-wide shape, lobulated or extra-thyroidal extension, and poorly defined margins
206
What are macrocalcifications?
Macrocalcifications are large calcified areas within a thyroid nodule that can be seen on ultrasound
207
What is the significance of a cold nodule on a Tc-99 uptake scan?
A cold nodule is typically more suspicious for malignancy compared to hot nodules
208
What is the gold standard method for determining if a thyroid nodule is benign or malignant?
Tissue biopsy with fine needle aspiration (FNA) and histological/cytological assessment
209
What is the most common type of thyroid cancer?
Papillary thyroid cancer, accounting for 80% of cases
210
What are the characteristics of medullary thyroid cancer?
Medullary thyroid cancer is typically seen with MEN-2 Syndrome and comprises about 5% of thyroid cancer cases
211
What is the prognosis of anaplastic thyroid cancer?
Anaplastic thyroid cancer carries the worst prognosis
212
What are common risk factors for thyroid cancer?
Genetic predispositions, ionizing radiation exposure, and environmental factors
213
What does TNM classification stand for in staging thyroid cancer?
Tumor, Node, Metastasis classification
214
What is the recommended management for papillary thyroid cancer less than 1 cm?
Hemi- or total-thyroidectomy with surveillance
215
What is the first-line treatment for established osteoporosis?
Lifestyle modifications and pharmacological treatments
216
What is the role of dual-energy X-ray absorptiometry (DXA) in osteoporosis?
It is the gold standard investigation for assessing bone density
217
What T-score indicates osteoporosis?
A T-score of < -2.5
218
What is a common adverse effect of bisphosphonates?
Osteonecrosis of the jaw
219
What is the mechanism of action of denosumab?
It is a monoclonal antibody that binds RANK-Ligand to prevent osteoclast activation
220
What is teriparatide used for?
It is an anabolic agent that stimulates osteoblast activity to increase bone density
221
What condition is characterized by a major deficiency in Vitamin D metabolism?
Rickets
222
What are classical findings in familial hypocalciuric hypercalcemia (FHH)?
Hypercalcemia, low urinary calcium concentrations, and normal PTH levels
223
True or False: Hot nodules on a Tc-99 scan are generally benign.
True
224
Fill in the blank: The most common type of thyroid cancer is _______.
Papillary thyroid cancer
225
What are the common skeletal deformities seen in children prior to puberty?
Bowed legs, exaggerated kyphosis, scoliosis
226
What can hypocalcaemia result in?
Tetany
227
What are the typical serum levels in conditions with hypocalcaemia?
Low serum calcium and phosphate; high serum alkaline phosphatase (ALP)
228
What do radiographs show in conditions with bone deformities?
Classical bony deformities with calcified areas of bone without mineralisation
229
What do bone density scans reveal in patients with bone demineralisation?
Demineralisation
230
What is the primary treatment for vitamin D deficiency?
Aggressive vitamin D supplementation (cholecalciferol)
231
What is the pathogenesis of Paget's Disease of Bone?
Localized and disorganized remaking of bone with predominant osteoclastic activity
232
What are the four stages of Paget's Disease?
* Osteoclast activity
* Mixed osteoclast/osteoblast remodeling
* Osteoblast activity
* Malignant degeneration
233
What viruses are strongly associated with Paget's Disease of Bone?
Paramyxoviruses
234
What genetic mutations are commonly associated with Paget's Disease?
* RANK
* SQSTM1
235
What do blood tests show in Paget's Disease?
Markedly elevated ALP; normal calcium, phosphate, PTH, and Vitamin D
236
What are the characteristic radiographic appearances in Paget's Disease?
Mixed lytic and sclerotic lesions of isolated bone regions
237
What bones are classically involved in Paget's Disease?
* Skull
* Vertebrae
* Pelvis (axial skeleton)
238
What is the effectiveness of bisphosphonates in treating Paget's Disease?
Effective
239
What is the prognosis of Paget's Disease?
Generally progressive, but most patients remain relatively asymptomatic
240
What hormone is secreted by the hypothalamus in the hypothalamic-pituitary-gonadal axis?
Gonadotropin-releasing hormone (GnRH)
241
What hormones do gonadotrope cells release?
* Luteinising hormone (LH)
* Follicle stimulating hormone (FSH)
242
What is the effect of LH and FSH in females?
Increase oestrogen and inhibin production
243
How do oestrogen and inhibin affect the hypothalamus and anterior pituitary gland?
Negative feedback to decrease secretion of GnRH and LH/FSH
244
What occurs during the follicular phase of the menstrual cycle?
LH and FSH stimulate several follicles to grow
245
What triggers ovulation?
LH surge
246
What does the dominant follicle produce during the follicular phase?
Estradiol
247
What happens during the luteal phase of the menstrual cycle?
Progesterone dominates as oestrogen levels fall
248
What hormone maintains the endometrium after fertilization?
Human chorionic gonadotropin (b-hCG)
249
What is the role of testosterone in males?
Produced by Leydig cells; provides negative feedback to the pituitary gland
250
What is the typical regimen for the Combined Oral Contraceptive Pill (COCP)?
21 oestrogen/progestogen containing tablets and 7 days of placebo
251
What happens with regular breastfeeding in terms of hormonal feedback?
Reduces GnRH and LH/FSH secretion
252
What are common causes of female infertility?
* Primary ovarian failure
* Polycystic ovarian syndrome
* Tubal obstruction
* Endometriosis
253
What characterizes endometriosis?
Presence of endometrium outside of the uterus
254
What is the gold standard method for diagnosing endometriosis?
Tissue identification on laparoscopy
255
What are the management options for endometriosis?
* Surgical ablation
* Analgesia
* Contraception
* GnRH agonists
* In vitro fertilisation
256
What is the strongest risk factor for Polycystic Ovarian Syndrome (PCOS)?
Obesity
257
What causes infertility in PCOS?
Excess oestrogen, LH predominance, and increased ovarian androgen production
258
What are the symptoms of PCOS?
* Weight gain
* Amenorrhoea
* Hirsutism
* Acne
259
What criteria are used to diagnose PCOS?
Rotterdam Criteria require 2 of 3 findings: * Oligo/anovulation
* Excess androgens
* Polycystic ovaries on ultrasound
260
What genetic mutation is most commonly associated with Congenital Adrenal Hyperplasia?
21-hydroxylase deficiency
261
What is the treatment for Congenital Adrenal Hyperplasia?
Replacement of glucocorticoids and mineralocorticoids
262
What is the clinical triad of primary ovarian failure?
* Amenorrhoea
* Low oestrogen levels
* Elevated LH/FSH
263
What are common causes of primary ovarian failure?
* Idiopathic
* Autoimmune
* Tuberculosis
* Radiation therapy
264
What are common causes of male infertility?
* Low sperm count
* Impaired sperm function
265
What chromosomal abnormality is associated with Klinefelter's Syndrome?
47 XXY karyotype
266
What are some signs and symptoms of Klinefelter's Syndrome?
* Infertility
* Small testes
* Hypergonadotrophic hypogonadism
* Gynaecomastia
267
What is the diagnostic method for Klinefelter's Syndrome?
Chromosomal assessment via FISH
268
What are common signs and symptoms of Klinefelter's Syndrome?
* Infertility
* Small testes
* Hypergonadotrophic hypogonadism
* Less muscular build, fat deposition and less body hair
* Cognitive impairment
* Gynaecomastia
* Increased risk of female predominant conditions such as autoimmunity, venous thromboembolism, breast cancer and osteoporosis
## Footnote
Cognitive impairment may be subtle in Klinefelter's Syndrome
269
What investigations reveal in Klinefelter's Syndrome?
* Decreased testosterone
* Increased LH/FSH
* Decreased sex hormone binding globulin
## Footnote
These findings are crucial for diagnosis and management.
270
How is Klinefelter's Syndrome diagnosed?
Diagnosis is confirmed on chromosomal assessment via FISH
## Footnote
FISH stands for Fluorescence In Situ Hybridization.
271
What is the controversy regarding the management of Klinefelter's Syndrome?
No treatment can reverse the underlying genetic abnormalities
## Footnote
Testosterone replacement is a consideration but remains controversial.
272
What is the expected trend of testosterone levels in males as they age?
Testosterone levels are expected to fall slightly with age
## Footnote
This trend is a natural part of aging.
273
Why is testosterone supplementation not subsidised by the PBS in Australia for older males?
Limited evidence to prove the benefit of testosterone replacement in such groups
## Footnote
The PBS is the Pharmaceutical Benefits Scheme in Australia.
274
What are potential benefits of testosterone replacement?
* Libido
* Bone health
## Footnote
Benefits may vary among individuals.
275
What are potential adverse effects of testosterone replacement?
* Cardiovascular disease
* Prostate cancer
## Footnote
Risks should be weighed against benefits when considering therapy.
276
What conditions does the PBS subsidise treatment for regarding androgen deficiency?
Androgen deficiency due to hypogonadotrophic hypogonadism or proven testicular causes
## Footnote
Treatment eligibility is based on specific medical conditions.
277
Which testosterone preparation is better tolerated?
Topical preparations
## Footnote
They do not increase haematocrit levels or raise the risk of thromboembolism.
278
What is the role of GnRH agonists in prostate cancer treatment?
GnRH agonists impair LH/FSH secretion, reducing testosterone production
## Footnote
Prostate cancer cells depend on testosterone for growth.
279
What are adverse effects of GnRH agonist treatment?
* Sexual dysfunction
* Hot flushes
* Increased cardiovascular disease risk
* Osteoporosis
* Anaemia
## Footnote
These effects can significantly impact quality of life.
