10. Endocrine Pathology - BP Flashcards
What is the epidemiology of pituitary adenomas?
Most occur in 30-60 (MCC of hyperpituitarism).
What hormones do pituitary adenomas produce?
- Prolactin (30%)
- GH
- ACTH
- TSH
What is the MC plurihormonal adenoma?
Adenoma producing both prolactin and GH.
What are the null cell pituitary adenomas?
Tumors that do not produce a significant amount of hormone - 2nd MC type of adenoma overall.
What are the levels of prolactin in the stalk effect in correlation with a prolactinoma?
Stalk effect prolactin is usually lower than the one secreted from the adenoma.
What is the clinical presentation of a prolactinoma?
Diagnosed earlier in females than males (20-40), because presenting symptoms are: 1. Galactorrrhea 2. Infertlity 3. Amenorrhea In males --> Decr. libido and impotence.
What levels of prolactin establish the diagnosis of prolactinoma?
Basal prolactin levels of >200ng/mL + a brain MRI.
What is important to remember about the differential diagnosis of prolactinoma?
Includes pharmacologic + physiologic causes in addition to pituitary lesions.
- Hypothyroidism –> TRH is high –> Causes release of prolactin.
- Antipsychotics that block dopamine
- Also pregnancy
What is the mutation involved in GH-secreting adenomas?
GNAS1 gene (20q13) - 40%.
What is the clinical presentation of GH-secreting tumor in children?
Gigantism - if the adenoma is present before the closure of the epiphyseal plates.
What is the clinical presentation of GH-secreting adenoma in adults?
Acromegaly:
- Growth in skin
- Soft tissue
- Thyroid gland
- Heart
- Liver
- Bones of face, hands, and feet.
What glucose abnormality is related to GH-secreting adenoma in adults?
GH high –> IGF-1 high –> Abnormal glucose tolerance –> DM.
How is the diagnosis of GH-secreting adenoma established?
Failure to suppress GH levels with an oral load of glucose; IGF-1 levels HIGH.
How is the diagnosis of and ACTH-secreting adenoma made?
Suppression of cortisol and ACTH secretion with HIGH-DOSE dexamethasone challange, but no response to low-dose dexamethasone.
What is the Nelson syndrome?
Patient with undiagnosed pituitary ACTH-secreting adenoma undergoes adrenalectomy –> pituitary adenoma has aggressive growth due to loss of feedback inhibition.
What is the gross morphology of a pituitary adenoma?
Hormone producing adenomas can be small - <1cm.
What is the microscopic morphology of a pituitary adenoma?
Monomorphous proliferation of cells.
Adenomas have no reticulin, in contrast to the normal anterior pituitary gland.
What is the clinical presentation of a pituitary adenoma?
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.
What percentage of pituitary gland must be lost for hypopituitarism to occur?
75% or more.
Mention the main causes of hypopituitarism.
- Null cell pituitary adenoma
- Ischemic injury
- Pituitary apoplexy
- Empty sella syndrome
What happens in Sheehan syndrome?
Pregnancy causes enlargement of the pituitary gland due to increased number of prolactin-secreting cells.
Give a basic description for pituitary apoplexy.
Hemorrhage into the pituitary gland, usually into an adeenoma.
What is the clinical presentation of pituitary apoplexy?
Rapid onset headache and diplopia.
What are the main complications of pituitary apoplexy?
- Hypopituitarism
- Diabetes insipidus
- Potentially cardiovascular collapse and death
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.
What is the clinical presentation of hypopituitarism?
- GH deficiency
- TSH def.
- ACTH def.
- ADH def.
Mention some types of mass effect?
- Visual field abnormalities –> pressure on the optic chiasm.
- Elevated ICP –> Headache, nausea, vomiting.
- Obstructive hydrocephalus
- Cranial nerve palsies
- Diabetes insipidus
- Hypothalamic disturbances
What are the main causes of mass effect?
- Pituitary adenomas (MC null cell adenomas).
- Metastatic carcinoma
- Craniopharyngioma
What is the epidemiology of a Craniopharyngioma?
Age ranges: 5-15 and >50.
MCC of hypothalamic disturbances in children.
What are the two types of craniopharyngioma?
- Adamantinomatous –> commonly calcify.
2. Papillary
What is important to remember about craniopharyngioma?
- Derived from Rathke pouch
- Most are suprasellar
- Prognosis depends upon completeness of surgical excision.
What are the 2 syndromes commonly associated with the posterior pituitary?
SIADH and diabetes insipidus
What are the main causes of SIADH?
- Ectopic (small cell lung carcinoma)
- Non neoplastic diseases of the lung (TB, pneumonia)
- CNS disorders (meningitis, abscess, trauma)
- Injury to hypothalamus or posterior pituitary
What is the mechanism of SIADH?
Incr. retention of water by incr. ADH leads to hyponatremia.
What are the symptoms of SIADH?
- Headache
- Anorexia
- Vomiting
- Confusion
- Stupor
- Coma and seizures
- Delirium and dementia
What are the lab findings of SIADH?
Hyponatremia, decr. serum osmolarity, inappropriately concentrated urine (>100mOsm/kg) + low BUN.
What are the causes of central diabetes insipidus?
- Head traum
- Neoplasms
- Langerhans cell histiocytosis
- Infectious processes
- Surgical procedures
- Autoimmune diseases
What are the 2 main causes of nephrogenic diabetes insipidus?
- Chronic renal failure
2. Sickle cell anemia
What are the 2 main symptoms of diabetes insipidus?
Polyuria and polydipsia.
What condition must be included in the differential diagnosis of diabetes insipidus?
Primary polydipsia
What can cause the goiter (enlargement of the thyroid gland)?
Hyper/hypo/euthyroidism
What are the two types of goiter?
Endemic (in areas of iodine deficiency) and sporadic.
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.
Give an overview of hyperthyroidism.
Incr. basal metabolic rate + organ’s sensitivity to catecholamines.
What is apathetic hyperthyroidism?
Seen MC in elderly patients, and is characterized by flat effect, weight loss, weakness, and emotional lability.
What are the signs and symptoms of hyperthyroidism?
- Heat intolerance
- Sweating, warm, flushed, skin.
- Weight loss + incr. appetite.
- Palpitations, tachycardia, tremor, anxiety, hyperactivity.
- Diarrhea
- Fine hair
What is important to remember in hyperthyroidism?
Tachycardia, tremor, and sweating are due to incr. sensitivity to catecholamines.
What are the lab findings in primary hyperthyroidism?
Decr. TSH + elevated T4 - occasionally, patients have only an elevated T3.
What are the 2 MCC of primary hyperthyroidism?
Graves and toxic goiter.
What is the pathogenesis of Graves?
Due to anti-TSH receptor antibody that stimulates the receptor, resulting in production of T3 and T4.
What is the epidemiology of Graves?
Occurs between 20-40 years of age - female 7:1.
What HLA associations do we see in Graves?
HLA-B8, HLA-DR3.
What is the gross morphology of Graves?
Thyroid gland is diffusely enlarged, but not nodular.
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.
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.
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.
Mention some rare causes of primary hyperthyroidism.
- Thyroid adenoma
- Post partum thyroiditis
- Amiodarone
- Iodinated contrasted media
Mention some causes of secondary hyperthyroidism.
- Struma ovarii (ovarian teratoma composed of thyroid tissue).
- Hydatidiform mole - proliferation of trophoblasts that cause excessive production of hCG –> intrinsic TSH-like activity.
Give a basic description of thyroid storm.
Abrupt onset of severe hyperthyroidism.
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.
What are the complications of thyroid storm?
Cardiac dysrhythmias and sudden death.
What is the clinical presentation of thyroid storm?
- Fever
- Flushing
- Sweating
- Agitation
- Marked weakness
- Mental status changes
- Hyperthermia
- Also tachycardia, a-fib, and delirium
What are the main signs and symptoms of hypothyroidism?
- Weight gain
- Cold intolerance and cool skin
- Thinning hair and loss of lateral portion of eyebrows.
- UP diastolic pressure
- Bradycardia
- CHF
- Delayed relaxation of deep tendon reflexes (Woltman sign) + carpal tunnel syndrom
- Apathy - facial edema - depression
- Menorrhagia - galactorrhea
- Constipation
What are the two types of hypothyroidism?
Cretinism and myxedema.
Give a basic description of cretinism.
Hypothyroidism occurring during infancy or childhood.
Why are newborns screened for evidence of hypothyroidism?
Because cretinism is an important PREVENTABLE cause of mental retardation.
What are the main features of cretinism?
- Severe mental retardation due to impaired development of the brain.2. Skeletal abnormalities (short stature)
- Coarse facial features and protruding tongue (!)
What are the major causes of cretinism?
- Iodine deficiency
- Maternal hypothyroidism - if it occur early in pregnancy, before development of the fatal thyroid gland.
- Inborn metabolic errors in the fetus that interfere with normal synthesis of thyroid hormones (rare).
Give a basic description of myxedema.
Hypothyroidism occuring in older children and adults.
What are the causes of myxedema?
Primary hypothyroidism –> Hashimoto, idiopathic, iodine deficiency.
Secondary hypothyroidism –> Pituitary problem.
What are the complications of myxedema?
Mostly in elderly –> Altered mental status + with or without coma.
What are the signs of myxedema coma?
More common in females - rare in patients <60.
- Altered mentation
- Hypothermia
- Hypotension
- Myxedematous physical examination
What are the causes of myxedema coma?
- UTI
- Sepsis
- Trauma
- Side effect of medication
What are the lab findings in primary hypothyroidism?
Incr. TSH + Decr. T3/T4
What are the lab findings in secondary hypothyroidism?
Decr. TSH + Decr. T3/T4
What is the pathogenesis of Hashimoto thyroiditis?
Inflammatory autoimmune destruction of the thyroid gland.
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.
What is the gross morphology of Hashimoto thyroiditis?
Pale, vaguely nodular thyroid gland.
What is the microscopic morphology of Hashimoto thyroiditis?
Lymphocytic infiltrate, usually with follicle formation and plasma cells, and oncocytic change in follicular epithelium.
What is the clinical presentation of Hashimoto thyroiditis?
- Insidious onset of hypothyroidism due to gradual loss of thyroid function.
- 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.
- Symptoms of hypothyroidism may be present - BUT if neck pain –> suggest other etiology.
- Other autoimmune might coexist.
How do we make the diagnosis of Hashimoto?
High TSH - Anti-thyroid peroxidase and anti-thyroglobulin antibodies are present in 90% of cases.
What is important to remember about acute suppurative thyroiditis?
It is a rare complication of septicemia.
What is the clinical presentation of acute suppurative thyroiditis?
- High fever
- Redness of skin overlying the thyroid gland
- Thyroid gland tenderness
What is the epidemiology of subacute (de Quervain or granulomatous) thyroiditis?
30-50.
Females 3:1 to 5:1.