Flashcards in Endocrine Deck (81)
Normal fasting blood glucose values:
72-100 mg/dl (4.0-5.7 mmol/L)
Normal Random blood glucose values:
<180 mg/dl (10 mmol/L)
Other causes of Diabetes Mellitus
1) Pancreatic disease
2) Hormonal antagonists to insulin
3) Drug & chemical induced
4) Genetic syndromes
Hormonal antagonists to insulin
2) Growth Hormone
Genetic syndromes involved in etiology of Diabetes Mellitus
1) Down's Syndrome
2) Turner's Syndrome
Type 1 D.M. etiology (general)
Most cases: 1) immune mediated destruction of pancreas through autoimmune attack on pancreatic B cells
3) Environmental factors
Type 1 D.M. etiology (genetic factors)
Type 1 D.M. etiology (environmental factors)
Association with viruses:
2) Coxsackie B4
Type 2 D.M. etiology (general)
caused by combination of B cell failure and insulin resistance
Type 2 D.M. etiology (genetic factors)
1) Stronger than type 1 (80% concordance in identical twins)
2) No HLA associations
3) Polygenetic disorder (but environmental factors also involved -> obesity)
More than half of the patients with D.M. II have BMI between what?
What is the RR for DM II for BMI > 35 kg/m2?
100 fold than BMI <22 kg/m2
How does obesity lead to DM?
Increased production of insulin antagonists, such as fatty acids and TNF by adipose tissue, especially in central obesity.
Pancreatic Pathology in DM. 1
1) Selective destruction of insulin-secreting beta cells
2) Insulitis, a chronic inflammatory infiltrate of the islets affecting primarily insulin containing islets
Pancreatic Pathology in DM 2
1) Moderate reduction islet tissue
2) Variable degrees deposition of amyloid.
Long term complications of Diabetes Mellitus
3) Eye disease
4) Heart disease
6) Problems of feet
Clinical symptoms of DM (prominent in uncontrolled type 1)
4) Weight loss
6) Blurred vision
8) Hyperventilation (Kussmaul breathing)
Why is there polyuria in DM?
Why is there thirst in DM?
Why is there weight loss in DM?
Why is there blurred vision in DM?
Dehydration of lens, and of aqueous and vitreous humour
Why is there vomiting in DM?
Ketones stimulate the area postrema
Why is there hyperventilation in DM?
Respiratory compensation to metabolic acidosis
What are the biochemical signs in DM?
Why is glycosylated hemoglobin a good monitor to manage DM?
-Hemoglobin reacts with glucose non-enzymatically to produce HcA1.
-HbA1c is the major fraction of glycosylated hemoglobin
-HbA1c levels give an integrated measure of glucose concentrations over the previous 2-3 months
Acute complications of DM
1) Hypoglycemia (diabetes treatment complication)
2) Diabetic ketoacidosis
3) Hyperosmolar nonketotic coma
4) Lactic acidosis
Precipitating factors of Diabetic Ketoacidosis
1) Infection or acute illness
3) Emotional disturbance
4) Missed insulin dose
Most common cause of hypopituitarism
Tumors which cause hypopituitarism
3) Cerebral and secondary tumors
Vascular causes of hypopituitarism
1) Sheehan's syndrome
2) Severe hypotension
Infectious causes of hypopituitarism
Hypothalamic disorders which cause hypopituitarism
2) Functional disorders
3) Isolated deficiency of GHRH
4) Isolated deficiency of LH/FSH-RH (GnRH secretion)
Iatrogenic causes of hypopituitarism
Miscellaneous causes of hypopituitarism
Pattern of hormone deficiency of the anterior pituitary
Which hormone is maintained in anterior pituitary hormone deficiency?
Drugs that cause nephrogenic D.I.
Metabolic causes of D.I.
SIADH will cause?
Water retention and hyponatremia
Presentation of SIADH
1) Hyponatremia can be asymptomatic or assoc with nonspecific symptoms
2) Severe hyponatremia, specially if there is rapid fall in serum sodium, can cause neurological symptoms, coma and death.
Causes of SIADH
1) Post operative
2) Intra-cranial disease: encephalitis, meningitis, head injury
3) Neoplasms: small cell carcinoma of the lung
4) Pulmonary disease: pneumonia, tuberculosis
Possible mechanisms of non-thyoridal illness (NTI)
1) Decreased peripheral conversion of T4 to T3
2) Abnormality of binding protein
3) Effects of circulating inflammatory mediators on metabolism of thyroid hormones
Characterization of papillary carcinoma of the thyroid gland
-presence of papillae
-tend to spread to local lymph nodes
Characterization of follicular carcinoma of thyroid gland
-Well differentiated follicles, which can be difficult to differentiate from normal thyroid tissue
-Invade the capsules and spread into blood vessels
Disorders that stem from overactivity of adrenal cortex
1) Cushing's syndrome
What are the clinical features of Addison's disease?
5) Abdominal pain
7) postural hypotension
What precipitates an adrenal crisis?
Infection in a patient with adrenocortical insufficiency.
What characterizes an adrenal crisis?
1) Circulatory shock
2) Volume depletion
What is secondary adrenocortical insufficiency due to?
Describe the serum presentation of a person with Addison's disease
Plasma sodium - low
Postassium - high
Serum bicarbonate - low
Urea - high
Morning cortisol - low or normal
What is the levels of ACTH in Addison's Disease?
How do we manage patients with Addisons?
replace glucocorticoids and mineralocorticoids
Describe the renin activity and aldosterone levels in pt with Addisons
Renin - high
Aldosterone - low
What is the best test for Addisons?
What is a specific test for Addisons?
Short synacthen test: administration of ACTH analogues to assess the residual capacity of the adrenal glands.
What are the causes of Hyperadrenalism : Cushing's syndrome
1) Exogenous steroids
2) Pituitary dependent
3) Adrenal adenoma
4) Ectopic ACTH
What are the clinical features of hyperadrenalism: Cushing's syndrome
1) Moon facies, truncal obesity, buffalo hump
3) Thin limbs and muscular weakness
4) Purple striae, fragile skin
5) Impaired glucose tolerance
6) Psychiatric disturbances
7) Menstrual disturbances, hirsutism
How does one diagnose Cushing's Syndrome?
1) Exclude exogenous glucocorticoids
2) Perform one of the following tests to confirm hypercortisolism:
- 24 hour urinary free cortisol (common)
-1 mg overnight DST (Dexamethasone suppression test)
- Late night salivary cortisol: new test
Describe the overnight Dexamethasone suppression test for Cushing's syndrome.
Involves taking a small dose of a cortisol-like drug called dexamethasone (1 mg) at 11 p.m. and having blood drawn for cortisol the following morning.
Normal individuals typically have very low levels of cortisol in these samples (s disease.
Physiological causes of hyperprolactinemia
Drugs that cause hyperprolactinemia
2) Oral Contraceptive Pill
What are the associations with MEN2A
1) Medullary Thyroid Cancer
3) Parathyroid Adenoma
What are the associations with MEN2B
1) Medullary Thyroid Cancer
2) Marfanoid habitus/mucosal neuroma
What is characteristic of Papillary Carcinoma of the thyroid gland?
1) Presence of papillae
2) Orphan Annie eye nuclei
3) Spread via lymphatics
What is characteristic of Follicular Carcinoma of the Thyroid gland?
1) Well differentiated
3) Hematogenous spread
4) Can only be diagnosed via visualization of capsular invasion. (Tissue biopsy, not aspiration)
5) Hurthle cells
Mutation of medullary carcinoma of the thyroid
Age of presentation of Medullary Carcinoma of the thyroid?
Sporadic and Inherited are above 50, except MEN syndrome assoc, which is an early presentation.
What is the difference between Cushing's Syndrome and Cushing's Disease?
Disease is due to pituitary adenoma
Syndrome is ectopic ACTH caused by non-pituitary tumor (i.e. small cell carcinoma of lung)
First functional change in Diabetic Nephropathy
First morphological change in Diabetic Nephropathy
Basement membrane thickening and mesangial expansion.
-subsequentyl nodular deposits and diffuse glomerulosclerosis
What is associated with established Diabetic Nephropathy?
Proteinuria (urinary albumin >300 mg/day)
Diabetic Neuropathy causes:
3) Orthostatic hypotension
4) Muscle atrophy
Two main causes of hypercalcemia:
2) Malignant diseases
Other causes of Hypercalcemia
1) Excessive vitamin D: Vit. D intoxication
2) Granulomas (tuberculosis, lymphoma, sarcoidosis) because they activate vitamin D
3) High bone turnover
What are the clinical features of hypercalcemia on the renal system?
– Polyuria and thirst
– Nephrocalcinosis; deposition of calcium crystals in kidney
– May lead to renal failure
What are the associations with Primary Adrenal Insufficiency (Addisons)
Autoimmunity of other organs such as:
1) Thyroid disease
2) Premature ovarian failure
3) DM 1
Secondary Adrenal Insufficiency is NOT associated with:
2) Electrolyte balances
Adrenal crisis is characterized by:
1) Circulatory shock
2) Volume Depletion
The low dose (2mg/day for 2 days) DST is given to rule out hypercortisolism due to what?
Conn's syndrome (hyperaldosteronism) causes what? Leading to what?
Causes: Na retention
3) metabolic alkalosis