10. Endocrine Pathology - BP Flashcards
(210 cards)
1
Q
What is the epidemiology of pituitary adenomas?
A
Most occur in 30-60 (MCC of hyperpituitarism).
2
Q
What hormones do pituitary adenomas produce?
A
- Prolactin (30%)
- GH
- ACTH
- TSH
3
Q
What is the MC plurihormonal adenoma?
A
Adenoma producing both prolactin and GH.
4
Q
What are the null cell pituitary adenomas?
A
Tumors that do not produce a significant amount of hormone - 2nd MC type of adenoma overall.
5
Q
What are the levels of prolactin in the stalk effect in correlation with a prolactinoma?
A
Stalk effect prolactin is usually lower than the one secreted from the adenoma.
6
Q
What is the clinical presentation of a prolactinoma?
A
Diagnosed earlier in females than males (20-40), because presenting symptoms are: 1. Galactorrrhea 2. Infertlity 3. Amenorrhea In males --> Decr. libido and impotence.
7
Q
What levels of prolactin establish the diagnosis of prolactinoma?
A
Basal prolactin levels of >200ng/mL + a brain MRI.
8
Q
What is important to remember about the differential diagnosis of prolactinoma?
A
Includes pharmacologic + physiologic causes in addition to pituitary lesions.
- Hypothyroidism –> TRH is high –> Causes release of prolactin.
- Antipsychotics that block dopamine
- Also pregnancy
9
Q
What is the mutation involved in GH-secreting adenomas?
A
GNAS1 gene (20q13) - 40%.
10
Q
What is the clinical presentation of GH-secreting tumor in children?
A
Gigantism - if the adenoma is present before the closure of the epiphyseal plates.
11
Q
What is the clinical presentation of GH-secreting adenoma in adults?
A
Acromegaly:
- Growth in skin
- Soft tissue
- Thyroid gland
- Heart
- Liver
- Bones of face, hands, and feet.
12
Q
What glucose abnormality is related to GH-secreting adenoma in adults?
A
GH high –> IGF-1 high –> Abnormal glucose tolerance –> DM.
13
Q
How is the diagnosis of GH-secreting adenoma established?
A
Failure to suppress GH levels with an oral load of glucose; IGF-1 levels HIGH.
14
Q
How is the diagnosis of and ACTH-secreting adenoma made?
A
Suppression of cortisol and ACTH secretion with HIGH-DOSE dexamethasone challange, but no response to low-dose dexamethasone.
15
Q
What is the Nelson syndrome?
A
Patient with undiagnosed pituitary ACTH-secreting adenoma undergoes adrenalectomy –> pituitary adenoma has aggressive growth due to loss of feedback inhibition.
16
Q
What is the gross morphology of a pituitary adenoma?
A
Hormone producing adenomas can be small - <1cm.
17
Q
What is the microscopic morphology of a pituitary adenoma?
A
Monomorphous proliferation of cells.
Adenomas have no reticulin, in contrast to the normal anterior pituitary gland.
18
Q
What is the clinical presentation of a pituitary adenoma?
A
Macroadenoma –> Symptoms due to mass effect (headache, visual abnormalities) + hypopituitarism due to compression and atrophy of the normal portion of the gland.
Also compression of III, IV, VI can occur.
19
Q
What percentage of pituitary gland must be lost for hypopituitarism to occur?
A
75% or more.
20
Q
Mention the main causes of hypopituitarism.
A
- Null cell pituitary adenoma
- Ischemic injury
- Pituitary apoplexy
- Empty sella syndrome
21
Q
What happens in Sheehan syndrome?
A
Pregnancy causes enlargement of the pituitary gland due to increased number of prolactin-secreting cells.
22
Q
Give a basic description for pituitary apoplexy.
A
Hemorrhage into the pituitary gland, usually into an adeenoma.
23
Q
What is the clinical presentation of pituitary apoplexy?
A
Rapid onset headache and diplopia.
24
Q
What are the main complications of pituitary apoplexy?
A
- Hypopituitarism
- Diabetes insipidus
- Potentially cardiovascular collapse and death
25
What happens in empty sella syndrome?
Condition due to incompetent diaphragm sella that allows herniation of arachnoid into the sella turcica --> presses on the pituitary --> atrophy of the gland.
26
What is the clinical presentation of hypopituitarism?
1. GH deficiency
2. TSH def.
3. ACTH def.
4. ADH def.
27
Mention some types of mass effect?
1. Visual field abnormalities --> pressure on the optic chiasm.
2. Elevated ICP --> Headache, nausea, vomiting.
3. Obstructive hydrocephalus
4. Cranial nerve palsies
5. Diabetes insipidus
6. Hypothalamic disturbances
28
What are the main causes of mass effect?
1. Pituitary adenomas (MC null cell adenomas).
2. Metastatic carcinoma
3. Craniopharyngioma
29
What is the epidemiology of a Craniopharyngioma?
Age ranges: 5-15 and >50.
| MCC of hypothalamic disturbances in children.
30
What are the two types of craniopharyngioma?
1. Adamantinomatous --> commonly calcify.
| 2. Papillary
31
What is important to remember about craniopharyngioma?
1. Derived from Rathke pouch
2. Most are suprasellar
3. Prognosis depends upon completeness of surgical excision.
32
What are the 2 syndromes commonly associated with the posterior pituitary?
SIADH and diabetes insipidus
33
What are the main causes of SIADH?
1. Ectopic (small cell lung carcinoma)
2. Non neoplastic diseases of the lung (TB, pneumonia)
3. CNS disorders (meningitis, abscess, trauma)
4. Injury to hypothalamus or posterior pituitary
34
What is the mechanism of SIADH?
Incr. retention of water by incr. ADH leads to hyponatremia.
35
What are the symptoms of SIADH?
1. Headache
2. Anorexia
3. Vomiting
4. Confusion
5. Stupor
6. Coma and seizures
7. Delirium and dementia
36
What are the lab findings of SIADH?
Hyponatremia, decr. serum osmolarity, inappropriately concentrated urine (>100mOsm/kg) + low BUN.
37
What are the causes of central diabetes insipidus?
1. Head traum
2. Neoplasms
3. Langerhans cell histiocytosis
4. Infectious processes
5. Surgical procedures
6. Autoimmune diseases
38
What are the 2 main causes of nephrogenic diabetes insipidus?
1. Chronic renal failure
| 2. Sickle cell anemia
39
What are the 2 main symptoms of diabetes insipidus?
Polyuria and polydipsia.
40
What condition must be included in the differential diagnosis of diabetes insipidus?
Primary polydipsia
41
What can cause the goiter (enlargement of the thyroid gland)?
Hyper/hypo/euthyroidism
42
What are the two types of goiter?
Endemic (in areas of iodine deficiency) and sporadic.
43
What is the pathogenesis of a goiter?
Low levels of thyroid hormones cause an increased level of TSH.
Alternating cycles of growth and degeneration lead to nodule formation.
44
Give an overview of hyperthyroidism.
Incr. basal metabolic rate + organ's sensitivity to catecholamines.
45
What is apathetic hyperthyroidism?
Seen MC in elderly patients, and is characterized by flat effect, weight loss, weakness, and emotional lability.
46
What are the signs and symptoms of hyperthyroidism?
1. Heat intolerance
2. Sweating, warm, flushed, skin.
3. Weight loss + incr. appetite.
4. Palpitations, tachycardia, tremor, anxiety, hyperactivity.
5. Diarrhea
6. Fine hair
47
What is important to remember in hyperthyroidism?
Tachycardia, tremor, and sweating are due to incr. sensitivity to catecholamines.
48
What are the lab findings in primary hyperthyroidism?
Decr. TSH + elevated T4 - occasionally, patients have only an elevated T3.
49
What are the 2 MCC of primary hyperthyroidism?
Graves and toxic goiter.
50
What is the pathogenesis of Graves?
Due to anti-TSH receptor antibody that stimulates the receptor, resulting in production of T3 and T4.
51
What is the epidemiology of Graves?
Occurs between 20-40 years of age - female 7:1.
52
What HLA associations do we see in Graves?
HLA-B8, HLA-DR3.
53
What is the gross morphology of Graves?
Thyroid gland is diffusely enlarged, but not nodular.
54
What is the microscopic morphology of Graves?
Hyperplastic follicles with papillae.
The papillae do not have fibrovascular cores.
Scalloping of the coloid at the periphery of the follicles.
55
What are the two main signs and symptoms that are specific to Graves and are not found in other causes of hyperthyroidism?
Exophthalmos and pretibial myxedema.
56
What is a toxic (diffuse or multinodular) goiter?
A goiter that usually has one or more nodules that produce T3 and T4.
However most are not hyperfunctioning.
57
Mention some rare causes of primary hyperthyroidism.
1. Thyroid adenoma
2. Post partum thyroiditis
3. Amiodarone
4. Iodinated contrasted media
58
Mention some causes of secondary hyperthyroidism.
1. Struma ovarii (ovarian teratoma composed of thyroid tissue).
2. Hydatidiform mole - proliferation of trophoblasts that cause excessive production of hCG --> intrinsic TSH-like activity.
59
Give a basic description of thyroid storm.
Abrupt onset of severe hyperthyroidism.
60
What is the cause of thyroid storm?
MC associated with Graves' disease in patients with secondarily incr. levels of catecholamines due to surgery and acute infection.
61
What are the complications of thyroid storm?
Cardiac dysrhythmias and sudden death.
62
What is the clinical presentation of thyroid storm?
1. Fever
2. Flushing
3. Sweating
4. Agitation
5. Marked weakness
6. Mental status changes
7. Hyperthermia
8. Also tachycardia, a-fib, and delirium
63
What are the main signs and symptoms of hypothyroidism?
1. Weight gain
2. Cold intolerance and cool skin
3. Thinning hair and loss of lateral portion of eyebrows.
4. UP diastolic pressure
5. Bradycardia
6. CHF
7. Delayed relaxation of deep tendon reflexes (Woltman sign) + carpal tunnel syndrom
8. Apathy - facial edema - depression
9. Menorrhagia - galactorrhea
10. Constipation
64
What are the two types of hypothyroidism?
Cretinism and myxedema.
65
Give a basic description of cretinism.
Hypothyroidism occurring during infancy or childhood.
66
Why are newborns screened for evidence of hypothyroidism?
Because cretinism is an important PREVENTABLE cause of mental retardation.
67
What are the main features of cretinism?
1. Severe mental retardation due to impaired development of the brain.2. Skeletal abnormalities (short stature)
3. Coarse facial features and protruding tongue (!)
68
What are the major causes of cretinism?
1. Iodine deficiency
2. Maternal hypothyroidism - if it occur early in pregnancy, before development of the fatal thyroid gland.
3. Inborn metabolic errors in the fetus that interfere with normal synthesis of thyroid hormones (rare).
69
Give a basic description of myxedema.
Hypothyroidism occuring in older children and adults.
70
What are the causes of myxedema?
Primary hypothyroidism --> Hashimoto, idiopathic, iodine deficiency.
Secondary hypothyroidism --> Pituitary problem.
71
What are the complications of myxedema?
Mostly in elderly --> Altered mental status + with or without coma.
72
What are the signs of myxedema coma?
More common in females - rare in patients <60.
1. Altered mentation
2. Hypothermia
3. Hypotension
4. Myxedematous physical examination
73
What are the causes of myxedema coma?
1. UTI
2. Sepsis
3. Trauma
4. Side effect of medication
74
What are the lab findings in primary hypothyroidism?
Incr. TSH + Decr. T3/T4
75
What are the lab findings in secondary hypothyroidism?
Decr. TSH + Decr. T3/T4
76
What is the pathogenesis of Hashimoto thyroiditis?
Inflammatory autoimmune destruction of the thyroid gland.
77
What is the epidemiology of hashimoto thyroiditis?
45-65.
Females 10:1 to 20:1.
Associated with both Down and Turner syndromes.
MCC of hypothyroidism and goiter.
78
What is the gross morphology of Hashimoto thyroiditis?
Pale, vaguely nodular thyroid gland.
79
What is the microscopic morphology of Hashimoto thyroiditis?
Lymphocytic infiltrate, usually with follicle formation and plasma cells, and oncocytic change in follicular epithelium.
80
What is the clinical presentation of Hashimoto thyroiditis?
1. Insidious onset of hypothyroidism due to gradual loss of thyroid function.
2. Early in the course of the disease, TRANSIENT hyperthyroidism may be seen because of severe inflammatory destruction of the gland --> releasing thyroid hormones in the blood.
3. Symptoms of hypothyroidism may be present - BUT if neck pain --> suggest other etiology.
4. Other autoimmune might coexist.
81
How do we make the diagnosis of Hashimoto?
High TSH - Anti-thyroid peroxidase and anti-thyroglobulin antibodies are present in 90% of cases.
82
What is important to remember about acute suppurative thyroiditis?
It is a rare complication of septicemia.
83
What is the clinical presentation of acute suppurative thyroiditis?
1. High fever
2. Redness of skin overlying the thyroid gland
3. Thyroid gland tenderness
84
What is the epidemiology of subacute (de Quervain or granulomatous) thyroiditis?
30-50.
| Females 3:1 to 5:1.
85
What is the pathogenesis of subacute thyroiditis?
Often follows a viral infection.
| HLA-B35 associated.
86
What is the microscopic morphology of subacute thyroiditis?
Lymphocytes and multinucleated giant cells.
87
What are the symptoms of subacute thyroiditis?
Neck pain and fever.
88
What are the signs of subacute thyroiditis?
1. Most characteristic is markedly tender thyroid gland upon palpation.
2. Early hyperthyroidism followed by a hypothyroid phase.
3. Most resume normal thyroid function within 8 weeks.
89
When evaluating nodules of the thyroid gland, what features are suggestive of malignancy?
1. Solitary nodule
2. Young male
3. Cold nodule (no radioactive iodine uptake)
90
When evaluating nodules of the thyroid gland, what symptoms are suggestive of malignancy?
1. Pain
2. Rapid growth rate
3. Change in voice
91
What is the most important risk factor for thyroid neoplasms?
History of radiation of the head and neck, especially if radiation occurred during the first two decades of life.
92
What are the five common types of thyroid neoplasms?
1. Papillary carcinoma
2. Follicular carcinoma
3. Follicular adenoma
4. Medullary carcinoma
5. Anaplastic carcinoma
93
What is the epidemiology of papillary thyroid carcinoma?
Any age, but usually 20-40.
| More than 80% of thyroid neoplasms.
94
What is the mutation associated with papillary thyroid carcinoma?
1. RET proto-oncogene (10q11)
2. BRAF
3. RAS
95
What is the main risk factor for papillary thyroid carcinoma?
Ionizing radiation
96
What is important to keep in mind about papillary thyroid carcinoma?
1. Has a good prognosis even with lymph node metastases.
| 2. Often multifocal.
97
When does papillary thyroid carcinoma has a poor prognosis?
Size >2.5cm and >45yrs.
| Also tall cell variant.
98
What is the microscopic morphology of papillary thyroid carcinoma?
1. Orphan Annie eye nuclei (clear nuclei)
2. Overlapping nuclei
3. Nuclear grooves
4. Pseudo-inclusions
5. Psammoma bodies
6. Papillary architecture
99
What is the age range of follicular thyroid adenoma/carcinoma?
Older patients.
100
What is the incidence of follicular thyroid adenoma/carcinoma?
Adenomas are frequent - carcinomas account for 10% of malignant thyroid neoplasms.
101
What mutations are associated with follicular thyroid adenomas?
TSH receptor gene GNAS1. (Gs protein - alpha subunit)
102
What mutation is associated with follicular thyroid carcinoma?
1. PAX8-PPAR1 (on t(2;3)(q13;p25)
| 2. 50% have a RAS mutation.
103
How do we distinguish papillary thyroid carcinoma from follicular thyroid carcinoma?
Nuclear features are important - papillary carcinoma can have a follicular growth pattern.
104
How do we distinguish a follicular adenoma from a follicular carcinoma?
Capsular invasion or blood vessel invasion.
105
In contrast to papillary thyroid carcinomas, are follicular adenomas/carcinomas multifocal?
No.
106
What is the prognosis for the follicular carcinoma of the thyroid?
Good, if minimally invasive.
107
What is the mutation associated with medullary thyroid carcinoma?
RET (in both MEN and non-MEN familial carcinomas).
108
What is important to remember about medullary carcinoma of the thyroid?
1. Association with C-cell hyperplasia.
| 2. Produce: Calcitonin, CEA, serotonin, VIP.
109
What is the microscopic morphology of medullary thyroid carcinoma?
Variable.
1. Trabecular + occasionally follicular patterns --> produce amyloid.
2. Both neoplastic cells and extracellular amyloid stain strongly for calcitonin.
110
What is the epidemiology of anaplastic thyroid carcinoma?
Older patients (>50)
111
What is important to keep in mind about anaplastic thyroid carcinoma?
Extremely poor prognosis - death within 1 year.
112
What is the microscopic morphology of anaplastic thyroid carcinoma?
Variable cell types.
1. Giant cells
2. Spindle cells
3. Small cells
113
What is the clinical presentation of anaplastic thyroid carcinoma?
1. Pain
2. Dysphagia
3. Hoarseness
114
What is the MCC of asymptomatic hypercalcemia?
Primary hyperparathyroidism.
115
What is the MCC of symptomatic hypercalcemia?
Metastatic tumor to the bones.
116
Mention some major signs and symptoms of hyperparathyroidism (due to hypercalcemia).
1. Fractures (weakened bones)
2. Kidney stones
3. Psychiatric symptoms
4. Abdominal pain
5. Seizures
6. Constipation
7. Muscular weakness and hypotonia
8. Short QT interval
117
What are the main causes of primary hyperparathyroidism?
1. Parathyroid adenoma (70-80%)
2. Hyperplasia
3. Carcinoma (rare <1%)
118
What mutations are associated with primary hyperparathyroidism?
1. PRAD1
| 2. MEN1
119
What is important to keep in mind about primary hyperparathyroidism?
Adenomas are confined to a single gland. If more than one gland is enlarged, the condition is called hyperplasia.
120
Mention 3 complications of primary hyperparathyroidism.
1. Osteitis fibrosa cystica
2. Brown tumors
3. Nephrolithiasis
121
What happens in osteitis fibrosa cystica?
Thinned cortex; hemorrhages and cysts in bone, with changes most prominent in the phalanges and skull.
122
What are the brown tumors seen as a complication of primary hyperparathyroidism?
Intraosseous accumulations of osteoclasts and giant cells.
| Brown color is imparted by areas of old hemorrhage.
123
What are the causes of secondary hyperparathyroidism?
1. Renal failure
2. Decr. phosphate excretion --> elevates phosphate levels --> depress calcium activity.
3. Also reduced synthesis of vitD due to renal failure.
4. VitD deficiency.
124
What is tertiary hyperparathyroidism?
Secondary hyperparathyroidism that becomes autonomous - the parathyroid gland no longer requires the stimulus of renal failure to undergo hyperplasia.
125
What is the pathogenesis of type I DM?
β-cell destruction, which is a possible autoimmune process with T lymphocytes reactive against islet cells.
Some cases may be caused by viral infection.
126
What are the HLA associations of type I DM?
HLA-DR3/4
127
What is the clinical presentation of type I DM?
1. Polyuria
2. Polydipsia
3. Polyphagia
128
How is the polyuria in DM explained?
Due to hyperglycemia causing incr. glucose in the urine --> osmotic polyuria.
129
How is polydipsia in DM explained?
From hyperosmolarity + water loss due to polyuria.
130
How is polyphagia in DM explained?
A catabolic state induced by the lack of glucose in cells --> due to breakdown of fats and protein.
131
What percentage of patients with type I DM initially present in diabetic ketoacidosis?
25%
132
What are the findings in diabetic ketoacidosis?
1. Hyperglycemia (>250mg/dL)
2. Ketosis
3. Metabolic acidosis with anion gap
133
What are the precipitating factors for diabetic ketoacidosis?
1. Infection
2. New-onset DM
3. Stress
4. Insulin deficiency (insulin non compliance)
134
What is the main idea in DKA?
A combination of insulin deficiency and relative glucagon excess.
135
What are the symptoms of DKA?
1. Nausea
2. Vomiting
3. Thirst
4. Abdominal pain
5. Weakness
6. Fatigue
136
What are the signs of DKA?
1. Tachycardia
2. Poor skin turgor and warm/dry skin (due to dehydration)
3. Ketones on breath
4. Altered mental status
137
What are the lab findings in DKA?
1. Hyperglycemia
2. Anion gap metabolic acidosis
3. Serum ketones
138
What is important to remember about DKA?
Patients feel sick, so they present earlier than patients with hyperosmolar nonketotic coma.
139
What is the pathogenesis of type II DM?
Genetic factors play a more important role in type II diabetes than in type I.
Inadequate secretion of insulin and peripheral resistance to insulin.
140
What is the clinical presentation of type II DM?
1. Weakness
2. Weight loss
3. Susceptibility to infections
141
What is important to remember about DKA and hyperosmotic coma?
It is commonly taught that type I DM develops DKA and type II DM develops hyperosmolar nonketotic coma.
In practice, DKA is very common in both types and hyperosmotic coma is unusual.
142
What are the lab findings in hyperosmolar non ketotic coma?
1. Marked hyperglycemia; no metabolic acidosis or ketonemia.
2. More dehydration than DKA
3. Low free fatty acid levels
4. No ketone bodies
5. Serum hyperosmolarity (>325mOsm/L)
143
What are the diagnostic criteria for diabetes mellitus?
1. Single random glucose level >200mg/dL in the presence of appropriate symptoms is sufficient for determining the diagnosis of DM.
2. Two random glucose tolerance tests with a level >200mg/dL in the absence of symptoms.
3. Two 2-hour (75g) glucose tolerance tests with a level >200mg/dL.
4. Fasting glucose >126mg/dL
144
What is important to keep in mind about HbA1C?
Gives a determination of the amount of glycosylated hemoglobin and is used for monitoring the disease process; not used for diagnostic purposes.
145
What is the pathogenesis of diabetic complications?
1. Activation of polyol pathway with accumulation of sorbitol.
2. Production of advanced glycosylation end products - from non enzymatic glycosylation of proteins.
3. Incr. oxidative damage.
4. Platelet dysfunction associated with incr. aggregation.
146
What is important to keep in mind about the complications of DM?
It is the number one cause of end-stage renal disease, blindness, and non traumatic lower extremity amputations.
147
What are the complications of DM in pancreas?
1. Reduction in number and size of islets - type I DM.
| 2. Amyloid deposition - type II DM.
148
What are the vessel complications of DM?
1. Atherosclerosis in large vessels.
2. Hyaline arteriolosclerosis in small vessels.
3. HTN due to hyperglycemia-induced endothelial dysfunction.
149
What are the kidney complications of DM?
1. Microalbuminuria (30-300mg/day) --> 10-20x incr. risk of progression to diabetic nephropathy.
2. Risk for pyelonephritis and papillary necrosis.
150
What are the eye complications of DM?
Non proliferative and proliferative retinopathy - cataracts.
151
What are the peripheral nervous system complications of DM?
```
Peripheral neuropathies (sensory loss more than motor loss).
Decr. sensation causes diabetics to be more prone to injury.
```
152
What are the skin and soft tissue extremities complications of DM?
Often develop ulcers and gangrene of the legs --> amputation.
153
What are the pregnancy complications of DM?
Large-for-gestational age infants are often born to diabetic mother.
154
What are the signs and symptoms of Cushing syndrome?
1. HTN
2. Weight gain
3. Fatigability
4. Weakness
5. Truncal obesity
6. Moon facies
7. Cutaneous stria
8. Hirsutism
9. Acne
155
What are the muscle problems in Cushing syndrome?
Proximal muscle weakness with atrophy of type 2 fast twitch myofibers.
156
What are the glucose metabolism problems in Cushing?
Inhibition of glucose uptake --> hyperglycemia + glucosuria + polydipsia.
157
What are the bone problems in Cushing?
Resorption of bone --> osteoporosis.
158
What is a very characteristic sign of Cushing in young adults?
Thinning of skin on the top of hands.
159
What are the ACTH-dependent causes of Cushing?
1. ACTH-secreting pituitary adenoma (70-80% of endogenous Cushing) --> called Cushing disease.
2. Ectopic ACTH secretion by small cell carcinoma.
3. Ectopic secretion by carcinoid tumor.
4. Other tumors producing ACTH --> Pancreatic + thyroid + adrenal.
160
What are the ACTH-independent causes of Cushing?
1. Adrenal gland adenoma and hyperplasia.
2. Adenomas are more common than hyperplasia.
3. Hyperplasia of the adrenals in Cushing is usually secondary due to stimulus provided by incr. ACTH production - not the primary cause of incr. cortisol.
161
What is the morphology of Cushing syndrome?
With incr. cortisol levels, Crooke hyaline change occurs in the anterior pituitary --> eosinophilic condensation within cytoplasm of ACTH-secreting pituitary basophils.
162
What is the test for diagnosing Cushing?
24-hour urine free cortisol level. Also loss of diurnal pattern of cortisol secretion (high in the morning, low at midnight).
163
What will suppression of cortisol with high-dose dexamethasone show?
The presence of ACTH-secreting pituitary adenoma.
164
What are the main causes of acute primary adrenocortical insufficiency?
1. Rapid withdrawal of exogenous steroids in chronic corticosteroid therapy.
2. Acute exacerbation of chronic adrenal insufficiency.
3. Anticoagulant therapy.
4. Post op patients with DIC + pregnancy.
5. Waterhouse-Friderichsen syndrome
165
What is the clinical presentation of acute adrenocortical insufficiency?
1. Severe abdominal pain
2. Nausea
3. Vomiting
4. Somnolence
5. Hypotension
166
What are the three main conditions associated with chronic addrenocortical insufficiency?
1. Addison disease
2. Secondary hypoadrenalism
3. Congenital adrenal hyperplasia
167
What is the MCC of chromic primary adrenocortical insufficiency in developed nations?
Addison
168
What is important to keep in mind about Addison?
Autoimmune --> Patients have incr. pigmentation of pressure points and buccal mucosa due to incr. levels of MSH --> produced along with ACTH from pro-opiomelanocortin.
169
Why there is no pigmentation in secondary adrenal insufficiency (pituitary disorders)?
Because this adrenal insufficiency is caused by a low ACTH.
170
What is the pathogenesis of Addison?
Auto-antibody to 21-hydroxylase and 17-hydroxylase.
171
Besides Addison, mention some other causes of chronic adrenal insufficiency?
1. Metastatic tumor
2. Infections (TB, Histoplasma, Coccidioides immitis)
3. Amyloidosis
4. Hemochromatosis
172
What are the symptoms of chronic adrenocortical insufficiency?
1. Weakness
2. GI disturbances
3. Weight loss
4. Salt craving
173
What are the signs of chronic adrenocortical insufficiency?
1. Hyponatremia
2. Hyperkalemia
3. Hypoglycemia
4. Hypotension
5. Decr. aldosterone
174
Give a basic description of secondary hypoadrenalism?
Condition due to pituitary gland destruction or due to suppression of adrenal gland (due to exogenous steroids).
175
What is important to keep in mind about secondary hypoadrenalism?
Mineralocorticoid levels are normal --> Hyperkalemia + salt craving does not occur.
Hyponatremia can occur but is due to incr. ADH in response to volume depletion.
176
What are the symptoms of secondary hypoadrenalism?
1. Weakness
2. Weight loss
3. Anorexia
4. Nausea
5. Vomiting
177
What are the lab findings in secondary hypoadrenalism?
Patients do not have decr. levels of aldosterone.
178
What does the ACTH stimulation test show?
Give ACTH and measure plasma cortisol level; in secondary hypoadrenalism, the cortisol level should increase.
179
Give a basic description of congenital adrenal hyperplasia.
Deficiency of an enzyme in the pathway of cortisol synthesis --> Lack of cortisol stimulates ACTH --> Adrenal hyperplasia.
180
How many types of congenital adrenal hyperplasia exist?
Five types - MC is due to 21-hydroxylase deficiency (95%).
181
What is the pathogenesis of congenital adrenal hyperplasia?
Failure of 21-hydroxylation of 17-hydroxyprogesterone and progesterone to 11-deoxycortisol and 11-deoxycortisone --> Deficient cortisol + aldosterone production.
ACTH secretion --> Incr. androstenedione + DHEA.
182
What happens in classic congenital adrenal hyperplasia?
Diagnosed at birth - 2/3 are salt wasting.
183
What happens in late onset congenital adrenal hyperplasia?
Diagnosed at or after puberty.
184
What is the clinical presentation of late onset congenital adrenal hyperplasia?
Hirsutism + ance + amenorrhea or oligomenorrhea.
185
What are the 2 main causes of primary hyperaldosteronism (Conn syndrome)?
Neoplas (usually adrenal adenoma) or adrenocortical hyperplasia.
186
What are the lab findings in Conn syndrome?
Hypernatremia and hypokalemia.
| ALSO incr. aldosterone + decr. renin.
187
What are the 2 MCC of hypokalemia?
1. Conn syndrome
| 2. Diuretics
188
What are the main causes of secondary hyperaldosteronism?
1. Decr. renal perfusion (due to renal artery stenosis or atherosclerosis).
2. Hypovolemia and edema.
3. Pregnancy.
189
What are the lab findings in secondary hyperaldosteronism?
Incr. aldosterone AND incr. renin.
190
What are the 4 main adrenal neoplasms?
1. Adrenal adenomas
2. Conn
3. Adrenocortical carcinoma
4. Pheochromocytoma
191
What is important to remember about adrenal adenomas?
Most are NON functioning - if ACTH is detected, a primary adrenal adenoma as a source of Cushing is unlikely.
192
What is the morphology of adrenal adenomas?
Yellow nodules in adrenal cortex.
193
Give a basic description of Conn syndrome.
Adenoma of the glomerulosa cells that produces aldosterone, which results in secondary HTN.
Conn syndrome can also be due to hyperplasia of the glands, but it is uncommon.
194
What is important in differentiating adrenocortical carcinoma from an adrenal adenoma?
Size (weight) - a >100grams is more likely to be a carcinoma.
195
Give a basic description of pheochromocytoma.
Tumor of the adrenal medulla that secretes epinephrine and norepinephrine --> episodic HTN.
196
What conditions are associated with pheochromocytoma?
1. MEN2A/2B
2. VHL syndrome
3. von Recklinghausen disease of bonee
4. Sturge-Weber syndrome
197
What is important to keep in mind regarding pheochromocytoma?
10% familial
10% extra-adrenal (in the carotid body or sympathetic chain)
10% bilateral
10% malignant (require metastases to determine malignancy)
10% occur during childhood
198
What is the gross morphology of pheochromocytoma?
Yellow-tan - can be hemorrhagic.
199
What is the microscopic morphology of pheochromocytoma?
1. Bland, monomorphous cells in nests (Zellballen pattern).
| 2. Nuclei have salt and pepper chromatin.
200
What can precipitate symptoms in pheochromocytoma?
Stress - surgery, acute infections.
201
What is the name for MEN1?
Wermer syndrome.
202
What is the mutation associated with MEN1?
MEN1 gene - 11q13 --> menin, a tumor suppressor.
203
What are the organs affected in MEN1?
The 3Ps.
Parathyroid --> Hyperplasia + adenoma
Pancreas --> Endocrine tumors, usually agressive --> gastrin + insulin.
Pituitary --> Prolactinoma, most common.
204
What is the name of MEN2A?
Sipple syndrome.
205
What is the mutation associated with MEN2A?
RET proto oncogene - 10q11.2.
206
What are the organs affected in MEN2A?
TAP!
Thyroid --> Medullary carcinoma of the thyroid.
Adrenal medulla --> Pheochromocytoma
Parathyroid --> Hyperplasia
207
What is the mutation associated with MEN2B?
RET proto oncogene, but different mutation than in MEN2A.
208
What are the organs affected by MEN2B?
Same as MEN2A, but spares parathyroid.
209
What are the 2 main diffrences between MEN2A and MEN2B?
1. MEN2B has no parathyroid problem.
| 2. MEN2B has ganglioneuromas + marfanoid habitus.
210
What are the 3 main causes of hyperpituitarism?
1. Adenomas
2. Hyperplasia
3. Carcinoma
