Medicine Marrow Pg No 935-944 (Endocrinology)
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Questions and Answers

Which of the following is NOT a macro priority in the management of Diabetes Mellitus?

  • Obesity (correct)
  • Kidney Disease
  • ASCVD
  • Heart Failure

    • Albuminuria is one of the macro priorities for managing Diabetes Mellitus.

    True

    Name one treatment priority for patients with Diabetes Mellitus who do not have kidney disease.

    Blood Pressure

    The macro priorities for Diabetes Mellitus management include Heart Failure, ASCVD, and __________.

    <p>Albuminuria</p> Signup and view all the answers

    Match the following management priorities with their descriptions:

    <p>Heart Failure = Condition affecting the heart's ability to pump blood ASCVD = Atherosclerotic cardiovascular disease Kidney = Involves monitoring albumin levels Blood Pressure = Regulation of force exerted by circulating blood</p> Signup and view all the answers

    Which type of pituitary adenoma is defined as being greater than 1 cm?

    <p>Macroadenoma</p> Signup and view all the answers

    Functioning adenomas do not cause hormonal dysfunction.

    <p>False</p> Signup and view all the answers

    What is one potential effect of a non-functioning adenoma related to the stalk effect?

    <p>Hypopituitarism</p> Signup and view all the answers

    A pituitary adenoma smaller than 1 cm is called a _________.

    <p>microadenoma</p> Signup and view all the answers

    Match the following effects with their related adenoma type:

    <p>Stalk effect = Non-functioning Adenoma Hormonal dysfunction = Functioning Adenoma Intracranial tension = Non-functioning Adenoma Prolactinoma = Non-functioning Adenoma</p> Signup and view all the answers

    Which of the following hormones is released from magnocellular neurons in the hypothalamus?

    <p>Oxytocin</p> Signup and view all the answers

    The anterior pituitary is influenced solely by releasing hormones from the hypothalamus.

    <p>False</p> Signup and view all the answers

    What is the role of the hypothalamic-hypophysial portal system?

    <p>It connects the hypothalamus to the anterior pituitary, allowing hormone transport.</p> Signup and view all the answers

    The hormone _____ is stored in the posterior pituitary and is involved in the regulation of water balance.

    <p>ADH</p> Signup and view all the answers

    Match the following hormones with their corresponding actions:

    <p>CRH = Stimulates ACTH secretion TRH = Stimulates TSH secretion GNRH = Stimulates LH and FSH secretion Prolactin = Inhibits milk production</p> Signup and view all the answers

    What is the most common type of pituitary adenoma associated with increased prolactin levels?

    <p>Prolactinoma</p> Signup and view all the answers

    Macro-prolactin is the bioactive form of prolactin.

    <p>False</p> Signup and view all the answers

    What type of pathway does prolactin act through?

    <p>JAK/STAT pathway</p> Signup and view all the answers

    The primary inhibitor of prolactin secretion is ______.

    <p>Dopamine</p> Signup and view all the answers

    Match the following substances with their role in prolactin regulation:

    <p>Estrogen = Stimulator Dopamine = Inhibitor TRH = Stimulator Prolactin Inhibitory Factor = Inhibitor</p> Signup and view all the answers

    What is the female to male ratio for microprolactinoma?

    <p>20:1</p> Signup and view all the answers

    Macroprolactinoma has a higher prevalence in males compared to females.

    <p>False</p> Signup and view all the answers

    What age range is most commonly affected by prolactinoma?

    <p>25-45 years</p> Signup and view all the answers

    The female to male ratio for macroprolactinoma is __________.

    <p>1:1</p> Signup and view all the answers

    Match the following types of prolactinoma with their respective female to male ratios:

    <p>Microprolactinoma = 20:1 Macroprolactinoma = 1:1</p> Signup and view all the answers

    What is the first-line medical treatment for symptomatic macroadenoma?

    <p>Dopamine agonists</p> Signup and view all the answers

    Bromocriptine is the preferred medication during pregnancy.

    <p>True</p> Signup and view all the answers

    What is the maximum dose increase for cabergoline in the management of symptomatic macroadenoma?

    <p>Increase to maximum dose per week as tolerated.</p> Signup and view all the answers

    The last resort for treating resistant prolactinoma when surgery is not an option is _____ therapy.

    <p>radiation</p> Signup and view all the answers

    Match the treatment options to their indications or notes:

    <p>Dopamine agonists = First-line treatment for macroadenoma Surgery = Indicated for dopamine agonist resistance Radiotherapy = For patients unfit for surgery Observation = Used for asymptomatic microadenoma</p> Signup and view all the answers

    What is a likely cause of prolactin levels greater than 200 µg/L?

    <p>Macroprolactinoma</p> Signup and view all the answers

    Macroprolactin is always symptomatic.

    <p>False</p> Signup and view all the answers

    Name one physiological condition that can cause prolactin levels to rise.

    <p>Pregnancy</p> Signup and view all the answers

    Prolactin levels between 40-100 µg/L can be indicative of __________ and systemic conditions.

    <p>drugs</p> Signup and view all the answers

    Match the prolactin level ranges with their associated conditions:

    <p>&lt; 25 µg/L = Normal levels 25-40 µg/L = Physiological factors 40-100 µg/L = Drugs/systemic conditions</p> <blockquote> <p>100 µg/L = Increased probability of adenoma</p> </blockquote> Signup and view all the answers

    Which structure is located posteriorly to the pituitary gland?

    <p>Sphenoid sinus</p> Signup and view all the answers

    The internal carotid artery is in lateral relation to the pituitary gland.

    <p>True</p> Signup and view all the answers

    What is the diagnostic sign of Central Diabetes Insipidus observed on a T1 MRI?

    <p>Absence of the bright spot</p> Signup and view all the answers

    A pituitary adenoma that is smaller than 1 cm is called a __________.

    <p>microadenoma</p> Signup and view all the answers

    Match the MRI type with its description:

    <p>T1 MRI (without contrast) = Isointense Pituitary T1 MRI (with contrast) = Tumor will not take contrast T1 Sagittal MRI = Isointense pituitary T1 MRI (Coronal image) = Isointense Pituitary</p> Signup and view all the answers

    What is the primary origin of the anterior pituitary?

    <p>Upgrowth from the roof of oral ectoderm</p> Signup and view all the answers

    The posterior pituitary develops from upgrowth from the oral ectoderm.

    <p>False</p> Signup and view all the answers

    What is the most important mutation associated with congenital hypopituitarism?

    <p>Prop-1 mutation</p> Signup and view all the answers

    Congenital hypopituitarism frequently results from pituitary __________.

    <p>dysplasia</p> Signup and view all the answers

    Match the following features with their related conditions:

    <p>Single central incisors = Defects in development due to Prop-1 mutation Bifid uvula = Defects in development due to Prop-1 mutation Cleft lip = Defects in development due to Prop-1 mutation Weight &gt; 1 gm in pregnancy = Enlargement of the pituitary gland</p> Signup and view all the answers

    Which type of cell is the earliest to appear in the anterior pituitary?

    <p>Corticotrophs</p> Signup and view all the answers

    The Somatotrophs make up 50% of the cells in the anterior pituitary.

    <p>True</p> Signup and view all the answers

    What hormone does the Gonadotrophs produce?

    <p>FSH and LH</p> Signup and view all the answers

    Corticotrophs secrete __________, which is a precursor for several hormones.

    <p>POMC</p> Signup and view all the answers

    Match the following hormones with their respective cell types:

    <p>GH = Somatotrophs PRL = Lactotrophs TSH = Thyrotrophs ACTH = Corticotrophs</p> Signup and view all the answers

    At what week do Lactotrophs appear?

    <p>12 to 24 weeks</p> Signup and view all the answers

    FSH and LH are produced by the Lactotrophs.

    <p>False</p> Signup and view all the answers

    What transcription factor mutation is associated with congenital hypopituitarism?

    <p>Prop-1</p> Signup and view all the answers

    Study Notes

    Pituitary Adenoma

    • Pituitary adenomas are tumors of the pituitary gland.
    • Types:
      • Macroadenoma: > 1 cm
      • Microadenoma: < 1 cm
    • Non-functioning Adenoma:
      • Stalk effect: leads to hypopituitarism and prolactinoma.
      • Mass effect: leads to intracranial tension
    • Functioning Adenoma:
      • Leads to hormonal dysfunction

    Hypothalamus & Pituitary Gland

    • Hypothalamus relation with anterior pituitary:
      • Hypothalamic influence over hormones:
        • Positive: CRH, TRH, GNRH, GHRH (Some inhibitory effect of somatostatin)
        • Negative: Prolactin (By prolactin inhibitory factor PRIF - Dopamine)
    • Hypothalamus relation with posterior pituitary:
      • Supraoptic and paraventricular neurons in Hypothalamus
        • Magnocellular neurons produce oxytocin
        • Pro vasopressin travels to posterior pituitary neurons
        • Cleaves into Neurophysin and Copeptin
        • ADH stored in posterior pituitary

    Prolactin

    • Constituent:
      • Polypeptide of 199 amino acids
      • Forms microprolactin (little prolactin) 23KD: Bioactive form
      • Macro-prolactin: inactive form assessed by gel filtration chromatography
      • Similar to Growth Hormone (GH): produced from lateral part of pituitary gland by lactotroph cells
    • Function:
      • Acts via JAK/STAT pathway
      • Induces and maintains lactation in an already primed breast (Estrogen + Progesterone)
    • Stimulators:
      • Estrogen
      • TRH
      • VIP
      • Oxytocin
      • REM sleep
    • Inhibitors:
      • PRIF (Prolactin Inhibitory Factor)/Dopamine via tubulo-infundibular pathway

    Prolactinoma

    • Causes:
      • α-subunit of FSH secreting adenoma (most common), clinically insignificant
      • Prolactinoma (most common): microadenoma
      • GH secreting adenoma (most common): Acromegaly (macro-adenoma)
      • ACTH secreting adenoma (third most common): Cushing's disease (micro > macro)

    Prolactinoma Treatment

    • Asymptomatic microadenoma: Wait and watch (3-6 months)
      • Repeat MRI if size increases → Then treat
    • Symptomatic/macroadenoma:
      • Medical (first line): Dopamine agonists
        • Cabergoline (DOC):
          • A/E: Nausea, vomiting, postural hypotension, dizziness
          • ↑ ½ weekly dosing
        • Bromocriptine:
          • Used in pregnancy
          • Higher incidence of adverse events
          • Stop 7 days before lactation
      • Surgery:
        • Indications: Dopamine agonist resistance, persistent visual field defects after 1 month of medical Rx, unstable pituitary apoplexy, pregnancy; unresponsive to short course medical therapy
      • Radiotherapy (Gamma Knife stereotactic radiotherapy): Last resort (if patient unfit for surgery)

    Prolactinoma Prevalence

    • Sex:
      • Microprolactinoma: Female to Male ratio is 20:1
      • Macroprolactinoma: Female to Male ratio is 1:1 (men present late)
    • Age:
      • 25-45 years (most common)

    Hyperprolactinemia

    • Causes:
      • Drugs:
        • Da Blockers: Conventional antipsychotics
        • Metoclopramide: Atypical antipsychotic
        • Opiates
        • Verapamil

    Fasting Prolactin Levels

    Prolactin levels (µg/L) Associated Conditions
    < 25
    25-40 Physiological: Sleep, stress, Pregnancy (variable, up to 180 µg/L), Lactation, Chest wall stimulation.
    40-100 Drugs, systemic conditions.
    > 100 Adenoma (↑ probability)
    > 200 Definite adenoma (Rule out macroprolactin)

    Macroprolactin vs Hook Effect

    Macroprolactin Hook effect
    ↑ Prolactin levels ↑ Prolactin level
    Asymptomatic Tumor size not corresponding to prolactin levels

    Anterior Pituitary Cells

    Cell Type Percentage (%) Appearance (weeks)
    Somatotrophs 50% 12
    Lactotrophs 15% 12-24
    Thyrotrophs 5% 12
    Gonadotrophs 10% 12
    Corticotrophs 15% 6

    • Characteristics of each cell type:*

    • Somatotrophs: Appear by 12 weeks

    • Lactotrophs: Last cell to appear, between 12 and 24 weeks

    • Thyrotrophs: Appear by 12 weeks

    • Gonadotrophs: Appear by 12 weeks. Includes FSH and LH cells

    • Corticotrophs: Earliest cells to appear at 6 weeks; located in the center of the gland, and are basophilic.

    Pituitary Gland Hormones

    Hormone Description
    GH (Growth Hormone) Polypeptide hormone, 191 AA
    PRL (Prolactin) Polypeptide hormone, 199 AA
    TSH (Thyroid-Stimulating Hormone) Appears in the Thyroid Gland
    ACTH (Adrenocorticotropic Hormone) Stimulates the release of corticosteroids
    FSH (Follicle-Stimulating Hormone) Part of Gonadotropin, involved in sex hormone production
    LH (Luteinizing Hormone) Part of Gonadotropin, involved in sex hormone production

    Further Pituitary Gland Information

    • 20% of thyroid hormone produced by gland itself
    • Acidophilic cell: Located in the lateral portion of the gland. Vulnerable to ischemia. Includes GH-secreting adenomas, also expressing lactotrophs (20% of cases).
    • Hyperpigmentation: Associated with pigmentation, possible link to MSH receptors.
    • Corticotrophs: Largest granules (400-550nm), secrete POMC (Pro-opio-melanocortin).
    • Basophilic: Located in the center of the gland.

    Transcription Factors

    • Prop-1 mutation → congenital hypopituitarism
    • Pit-1 mutations and most common cause hypopituitarism
    • Tpit: Corticotroph development
    • GATA-2 → SF-1 → DAX-1 → Gonadotrophins

    Pituitary Gland Anatomy

    • The master gland of endocrine.

    Embryology

    • Anterior Pituitary: Origin: upgrowth from roof of oral ectoderm. Rathke's pouch (Surface).
    • Posterior Pituitary: Origin: Downgrowth from floor of 3rd ventricle (Neurohypophysis).

    Applied Aspect

    • Congenital Hypopituitarism: most common cause Pituitary dysplasia.
    • Transcription factor defect: Prop-1 mutation (most important)
    • Anterior Pituitary only involved:
      • Midline craniofacial anomaly:
        • Rathke's pouch (Nasopharynx)
        • Cells from defect in midline migration
      • Outcomes (defects in development):
        • Single central incisors
        • Bifid uvula
        • Cleft lip

    Pituitary Gland Relations

    • Posterior Relation: Sphenoid Sinus

    • Lateral Relation: Cavernous sinus

    • Ventral Relation: Diaphragma sellae (Duramater layer), Injury CSF leak, Empty sella syndrome

    • Structures in relation to pituitary gland:*

    • Pituitary stalk

    • Diaphragma sellae

    • Internal carotid artery

    • Oculomotor nerve (III)

    • Trochlear nerve (IV)

    • Abducent nerve (VI)

    • Ophthalmic division of trigeminal nerve (V1)

    • Maxillary division of trigeminal nerve (V2)

    • Compressed pituitary gland

    • Pituitary adenomas: Transsphenoidal approach

    • Tumor Expansion: VI nerve involvement (first Lateral rectus palsy)

    MRI Imaging of Pituitary Gland

    MRI Type Description
    T1 MRI (Coronal image) Isointense Pituitary
    T1 Sagital MRI Isointense pituitary
    T1 MRI (without contrast) Isointense Pituitary
    T1 MRI (with contrast) Uniform uptake of contrast by Pituitary gland; In Adenoma: Tumor will not take contrast (Less vascularity) not uniform uptake by contrast.
    T1 MRI (Sagittal section) Normal bright spot of pituitary gland under red circle; Absence of bright spot: Diagnostic of Central DI (80% cases)

    Pituitary Gland Features

    • Weight: 600 mg
    • Pregnancy: > 1 gm (enlarges)
    • Blood loss (PPH): ↓ Blood supply to Gland
    • Sheehan Syndrome:

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    Description

    This quiz explores the types and effects of pituitary adenomas, as well as the relationship between the hypothalamus and the pituitary gland. Understand the dynamics of functioning and non-functioning adenomas, and their hormonal implications. Test your knowledge on these important concepts in neuroendocrinology.

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