Endocrine System Pathophysiology

Flashcards covering the pathophysiology, diagnostics, and treatments related to the endocrine system.

Endocrine System

The body’s chemical communication network—regulating everything from metabolism and growth to stress responses and fluid balance.

Hormones

Chemical messengers secreted by glands such as the pituitary, thyroid, adrenal glands, and pancreas.

Dysfunction

Profound dysfunction across multiple body systems caused by hormone disruption.

Dysregulated

How hormones become dysregulated must be understood to interpret labs, anticipate complications, and advocate for appropriate treatment.

Mechanisms

Key mechanisms by which endocrine dysfunction occurs must be understood.

Bloodstream

Endocrine glands secrete hormones directly into the bloodstream

Glucose

Use regulated by hormones, fat breakdown, and protein synthesis.

Aldosterone

Hormone that manages fluid and electrolyte balance.

Antidiuretic Hormone (ADH)

Hormone that manages fluid and electrolyte balance.

Hypothalamus

Produces releasing and inhibiting hormones (e.g., CRH, TRH, GHRH).

Anterior Pituitary

Triggered by hypothalamic hormones, releasing stimulating hormones (e.g., TSH, ACTH).

Stimulating Hormones

Prompt peripheral endocrine glands (e.g., thyroid, adrenal) to release stimulating hormones.

Feedback Loops

Mostly negative feedback, to maintain hormonal balance within the HPA axis.

Etiologies

Different etiologies can lead to hormone imbalances.

Dysgenesis

Congenital hormone deficiencies can be caused by dysgenesis

Androgen Insensitivity Syndrome

An inherited receptor defect.

Diabetes Insipidus

An inherited receptor defect that is X-linked nephrogenic.

Endocrine Tissues

The immune system may attack endocrine tissues, causing autoimmune disorders.

Hashimoto Thyroiditis

Autoimmune destruction of thyroid leads to hypothyroidism.

Graves Disease

Antibodies overstimulate TSH receptors, causing hyperthyroidism.

Addison Disease

Autoimmune destruction of adrenal cortex leads to cortisol and aldosterone deficiency.

Iodine Deficiency

Impairs thyroid hormone synthesis.

Lithium

Medications such as lithium can alter thyroid or renal ADH response.

Amiodarone

Medications such as amiodarone can alter thyroid or renal ADH response.

Hormone Deficiency

Radiation or surgical removal of glands results in hormone deficiency

Panhypopituitarism

Widespread hormonal deficiencies due to damage to the anterior pituitary.

Tumors

Can cause hormone excess.

Non-endocrine Tumors

May produce hormones outside normal feedback control.

Receptors

Target cells may be unresponsive due to fewer receptors.

Affinity

Decreased receptor affinity can cause target cells to be unresponsive (e.g., due to pH or genetic factors).

Block

Autoantibodies that block receptors or mimic hormone activity can cause target cells to be unresponsive.

Inactive Hormone

Glands may produce an inactive or insufficient hormone, often due to genetic or autoimmune conditions.

Hypothyroidism

Congenital hypothyroidism failure to synthesize thyroid hormone.

Inhibition

Tumors or cellular defects may prevent feedback inhibition.

Fatigue

A common symptom, these nonspecific symptoms challenge early detection.

Mood Shifts

Nonspecific symptoms challenge early detection.

Pharmacologic

Treatment ranging from pharmacologic to lifestyle interventions.

Lifestyle

Treatment ranging from pharmacologic to lifestyle interventions.

Gain

Weight gain with poor appetite is associated with hypothyroidism.

Coarse

Dry skin, coarse hair, constipation, and bradycardia are signs of hypothyroidism.

Bradycardia

Dry skin, coarse hair, constipation, and bradycardia can be present in hypothyroidism.

Goiter

May be present in hypothyroidism if TSH is elevated.

Myxedema

(Nonpitting edema) is a hallmark in severe cases of hypothyroidism.

Hyperplasia

Goiter due to thyroid hyperplasia.

Truncal Obesity

A clinical manifestation of Cushing Syndrome.

Buffalo Hump

Clinical manifestation of Cushing Syndrome.

Bruising

Easy bruising can be due to protein catabolism and Cushings syndrome.

Emotional Lability

Common symptom of Cushing Syndrome.

Hyperpigmentation

From excess ACTH stimulation of melanocytes.

Hyponatremia

From aldosterone deficiency in Addison's disease

Hyperkalemia

From aldosterone deficiency in Addison's disease

Polyruia

(Excess dilute urine) and polydipsia are clinical features of diabetes insipidus (DI).

Osmolality

Dehydration, hypotension, and increased serum osmolality are signs of diabetes insipidus (DI).

Hormone Testing

Accurate diagnosis of endocrine disorders relies on combining clinical findings with hormone testing and imaging.

Levothyroxine

(Synthroid) for hypothyroidism

Hydrocortisone

Replacement therapy for Addison disease

Fludrocortisone

Replacement therapy for Addison disease

Desmopressin

(DDAVP) for central diabetes insipidus

Methimazole

Inhibition of hormone overproduction, used in hyperthyroidism

Propylthiouracil (PTU)

Inhibition of hormone overproduction, used in hyperthyroidism

Ketoconazole

Inhibition of hormone overproduction, used to suppress cortisol in Cushing syndrome

Metyrapone

Inhibition of hormone overproduction, used to suppress cortisol in Cushing syndrome

Tolvaptan

ADH antagonists (e.g., tolvaptan) for SIADH in resistant cases

Thyroidectomy

Surgical or radiation therapy for severe Graves disease or thyroid nodules

Adrenalectomy

Surgical or radiation therapy for adrenal tumors in Cushing syndrome

Stereotactic

Pituitary surgery or stereotactic radiation for ACTH-producing adenomas

Restriction

Fluid restriction is the cornerstone of treatment in SIADH.

Hyponatremia

Educate on symptoms of worsening hyponatremia (e.g., confusion, weakness).

Hydration

Adequate hydration is critical, encourage free water intake for those with diabetes insipidus.

Dehydration

Teach signs of dehydration and when to seek IV fluid replacement, important for diabetes insipidus patients.

Infection

Stress the importance of infection prevention due to immunosuppression, important education for Cushing Syndrome patients.

Medical Alert ID

Teach patients to carry a medical alert ID and emergency hydrocortisone for Addison's disease

Fluid Balance

Endocrine glands secrete hormones that regulate metabolism, growth, reproduction, stress response, and fluid balance through the bloodstream.

Homeostasis

The hypothalamic–pituitary axis (HPA) is the central control system for many hormones, using feedback loops—especially negative feedback—to maintain homeostasis.

Receptor Insensitivity

Disorders may arise from glandular destruction, hormone-secreting tumor, receptor insensitivity, genetic mutations, or disrupted feedback regulation.

Hypernatremia

Polyuria, dehydration, hypernatremia; treated with desmopressin and hydration.

Diagnosis

Key lab markers include TSH, cortisol ACTH, osmolality, and specific gravity which are essential for accurate diagnosis and clinical decision-making.

Education

Lifestyle and Nursing Interventions: (e.g., fluid restriction, electrolyte monitoring, patient education are critical in managing SIADH, DI, and Addison disease.

Overactive

Surgery/Radiation is a treatment and can be performed for tumors or overactive glands