Signs and symptoms include: hypoglycemia, dehydration, weight loss, and disorientation. Additional signs and symptoms include weakness, tiredness, dizziness, low blood pressure that falls further when standing (orthostatic hypotension), cardiovascular collapse, muscle aches, nausea, vomiting, and diarrhea. These problems may develop gradually and insidiously. Addison's disease can present with tanning of the skin that may be patchy or even all over the body. Characteristic sites of tanning are skin creases (e.g. of the hands) and the inside of the cheek (buccal mucosa). Goitre and vitiligo may also be present. Eosinophilia may also occur.

There are three major types of adrenal insufficiency.

- Primary adrenal insufficiency is due to impairment of the adrenal glands.

- 80% are due to an autoimmune disease called Addison's disease or autoimmune adrenalitis.

- One subtype is called idiopathic, meaning of unknown cause.

- Other cases are due to congenital adrenal hyperplasia or an adenoma (tumor) of the adrenal gland.

- Secondary adrenal insufficiency is caused by impairment of the pituitary gland or hypothalamus. Its principal causes include pituitary adenoma (which can suppress production of adrenocorticotropic hormone (ACTH) and lead to adrenal deficiency unless the endogenous hormones are replaced); and Sheehan's syndrome, which is associated with impairment of only the pituitary gland.

- Tertiary adrenal insufficiency is due to hypothalamic disease and a decrease in the release of corticotropin releasing hormone (CRH). Causes can include brain tumors and sudden withdrawal from long-term exogenous steroid use (which is the most common cause overall).

Deficiency of all anterior pituitary hormones is more common than individual hormone deficiency.

Deficiency of luteinizing hormone (LH) and follicle-stimulating hormone (FSH), together referred to as the gonadotropins, leads to different symptoms in men and women. Women experience oligo- or amenorrhea (infrequent/light or absent menstrual periods respectively) and infertility. Men lose facial, scrotal and trunk hair, as well as suffering decreased muscle mass and anemia. Both sexes may experience a decrease in libido and loss of sexual function, and have an increased risk of osteoporosis (bone fragility). Lack of LH/FSH in children is associated with delayed puberty.

Growth hormone (GH) deficiency leads to a decrease in muscle mass, central obesity (increase in body fat around the waist) and impaired attention and memory. Children experience growth retardation and short stature.

Adrenocorticotropic hormone (ACTH) deficiency leads to adrenal insufficiency, a lack of production of glucocorticoids such as cortisol by the adrenal gland. If the problem is chronic, symptoms consist of fatigue, weight loss, failure to thrive (in children), delayed puberty (in adolescents), hypoglycemia (low blood sugar levels), anemia and hyponatremia (low sodium levels). If the onset is abrupt, collapse, shock and vomiting may occur. ACTH deficiency is highly similar to primary Addison's disease, which is cortisol deficiency as the result of direct damage to the adrenal glands; the latter form, however, often leads to hyperpigmentation of the skin, which does not occur in ACTH deficiency.

Thyroid-stimulating hormone (TSH) deficiency leads to hypothyroidism (lack of production of thyroxine (T4) and triiodothyronine (T3) in the thyroid). Typical symptoms are tiredness, intolerance to cold, constipation, weight gain, hair loss and slowed thinking, as well as a slowed heart rate and low blood pressure. In children, hypothyroidism leads to delayed growth and in extreme inborn forms to a syndrome called "cretinism".

Prolactin (PRL) plays a role in breastfeeding, and inability to breastfeed may point at abnormally low prolactin levels.

The hormones of the pituitary have different actions in the body, and the symptoms of hypopituitarism therefore depend on which hormone is deficient. The symptoms may be subtle and are often initially attributed to other causes. In most of the cases, three or more hormones are deficient. The most common problem is insufficiency of follicle-stimulating hormone (FSH) and/or luteinizing hormone (LH) leading to sex hormone abnormalities. Growth hormone deficiency is more common in people with an underlying tumor than those with other causes.

Sometimes, there are additional symptoms that arise from the underlying cause; for instance, if the hypopituitarism is due to a growth hormone-producing tumor, there may be symptoms of acromegaly (enlargement of the hands and feet, coarse facial features), and if the tumor extends to the optic nerve or optic chiasm, there may be visual field defects. Headaches may also accompany pituitary tumors, as well as pituitary apoplexy (infarction or haemorrhage of a pituitary tumor) and lymphocytic hypophysitis (autoimmune inflammation of the pituitary). Apoplexy, in addition to sudden headaches and rapidly worsening visual loss, may also be associated with double vision that results from compression of the nerves in the adjacent cavernous sinus that control the eye muscles.

Pituitary failure results in many changes in the skin, hair and nails as a result of the absence of pituitary hormone action on these sites.

Symptoms caused by hormone excess and associated mass effects include:

Hyperpituitarism is a condition due to the primary hypersecretion of pituitary hormones, it typically results from a pituitary adenoma. Children with hyperpituitarism is rare, disruption of growth regulation, either because of hormone hypersecretion or because of manifestations caused by local compression of the adenoma can occur.

Common signs and symptoms of Cushing's disease include the following:

- weight gain

- high blood pressure

- poor short-term memory

- irritability

- excess hair growth (women)

- Impaired immunological function

- red, ruddy face

- extra fat around neck

- moon face

- fatigue

- red stretch marks

- poor concentration

- irregular menstruation

The syndrome can present with variable symptoms, even between members of the same family harboring the same mutation. Typically most or all tissues are resistant to thyroid hormone, so despite raised measures of serum thyroid hormone the individual may appear euthyroid (have no symptoms of over- or underactivity of the thyroid gland). The most common symptoms are goiter and tachycardia. It has also been linked to some cases of attention deficit hyperactivity disorder (ADHD), although the majority of people with that diagnosis have no thyroid problems.

An association with depression has been proposed.

An "Addisonian crisis" or "adrenal crisis" is a constellation of symptoms that indicates severe adrenal insufficiency. This may be the result of either previously undiagnosed Addison's disease, a disease process suddenly affecting adrenal function (such as adrenal hemorrhage), or an intercurrent problem (e.g., infection, trauma) in someone known to have Addison's disease. It is a medical emergency and potentially life-threatening situation requiring immediate emergency treatment.

Characteristic symptoms are:

- Sudden penetrating pain in the legs, lower back, or abdomen

- Severe vomiting and diarrhea, resulting in dehydration

- Low blood pressure

- Syncope (loss of consciousness and ability to stand)

- Hypoglycemia (reduced level of blood glucose)

- Confusion, psychosis, slurred speech

- Severe lethargy

- Hyponatremia (low sodium level in the blood)

- Hyperkalemia (elevated potassium level in the blood)

- Hypercalcemia (elevated calcium level in the blood)

- Convulsions

- Fever

The less-common signs and symptoms of Cushing's disease include the following:

- insomnia

- recurrent infection

- thin skin and stretch marks

- easy bruising

- weak bones

- acne

- balding (women)

- depression

- hip and shoulder weakness

- swelling of feet/legs

- diabetes mellitus

- erectile dysfunction

Features that result from high level of GH or expanding tumor include:

- Soft tissue swelling visibly resulting in enlargement of the hands, feet, nose, lips and ears, and a general thickening of the skin

- Soft tissue swelling of internal organs, notably the heart with attendant weakening of its muscularity, and the kidneys, also the vocal cords resulting in a characteristic thick, deep voice and slowing of speech

- Generalized expansion of the skull at the fontanelle

- Pronounced brow protrusion, often with ocular distension (frontal bossing)

- Pronounced lower jaw protrusion (prognathism) with attendant macroglossia (enlargement of the tongue) and teeth spacing

- Hypertrichosis, hyperpigmentation and hyperhidrosis may occur in these patients.

- Acrochordon (skin tags)

- Carpal tunnel syndrome

Causes of adrenal insufficiency can be categorized by the mechanism through which they cause the adrenal glands to produce insufficient cortisol. These are adrenal dysgenesis (the gland has not formed adequately during development), impaired steroidogenesis (the gland is present but is biochemically unable to produce cortisol) or adrenal destruction (disease processes leading to glandular damage).

The most common clinical manifestations are related to mental status and gastrointestinal function; they include lethargy, anorexia, vomiting, weight loss, and weakness. Additional findings may include dehydration, bradycardia, weak femoral pulses, and abdominal pain. Polyuria and polydipsia, diarrhea, and shivering are occasionally reported.

Symptoms of hypoadrenocorticism can include vomiting, diarrhea, lethargy, lack of appetite, tremors or shaking, muscle weakness, low body temperature, collapse, low heart rate, and pain in the hind quarters. Hypoglycemia can also be present, and initially may be confused with seizure disorders, insulin-secreting pancreatic tumor (insulinoma), food poisoning, parvovirus enteritis, gastric volvulus, spinal or joint problems, earning hypoadrenocorticism the nicknames of "the Great Mimic" and "the Great Imitator". It is possible not to see any signs of the disease until 90% of the adrenal cortex is no longer functioning.

If hyponatremia (low sodium) and hyperkalemia (high potassium) are severe, the resulting hypovolemia, prerenal azotemia, and cardiac arrhythmias may result in an Addisonian crisis. In severe cases, the patient may be presented in shock and moribund. Addisonian crisis must be differentiated from other life-threatening disorders such as diabetic ketoacidosis, necrotizing pancreatitis, and septic peritonitis.

Thyroid hormone resistance (sometimes Refetoff syndrome) describes a rare syndrome in which the thyroid hormone levels are elevated but the thyroid stimulating hormone (TSH) level is not suppressed, or not completely suppressed as would be expected. The first report of the condition appeared in 1967. Essentially this is decreased end organ responsiveness to thyroid hormones. A new term "impaired sensitivity to thyroid hormone" has been suggested in March 2014 by Refetoff et al.

The various signs and symptoms in Sheehan's syndrome are caused by damage to the pituitary, which causes a decrease in one or more hormones it normally secretes (see Pathophysiology section). Since the pituitary controls many glands in the endocrine system, partial or complete loss of a variety of functions may result.

Most common initial symptoms of Sheehan's syndrome are agalactorrhea (absence of lactation) and/or difficulties with lactation. Many women also report amenorrhea or oligomenorrhea after delivery. In some cases, a woman with Sheehan syndrome might be relatively asymptomatic, and the diagnosis is not made until years later, with features of hypopituitarism. Such features include secondary hypothyroidism with tiredness, intolerance to cold, constipation, weight gain, hair loss and slowed thinking, as well as a slowed heart rate and low blood pressure. Another such feature is secondary adrenal insufficiency, which, in the rather chronic case is similar to Addison's disease with symptoms including fatigue, weight loss, hypoglycemia (low blood sugar levels), anemia and hyponatremia (low sodium levels). Such a woman may, however, become acutely exacerbated when her body is stressed by, for example, a severe infection or surgery years after her delivery, a condition equivalent with an Addisonian crisis. The symptoms of adrenal crisis should be treated immediately and can be life-threatening. Gonadotropin deficiency will often cause amenorrhea, oligomenorrhea, hot flashes, or decreased libido. Growth hormone deficiency causes many vague symptoms including fatigue and decreased muscle mass.

Uncommonly, Sheehan syndrome may also appear acutely after delivery, mainly by hyponatremia. There are several possible mechanisms by which hypopituitarism can result in hyponatremia, including decreased free-water clearance by hypothyroidism, direct syndrome of inappropriate antidiuretic hormone (ADH) hypersecretion, decreased free-water clearance by glucocorticoid deficiency (independent of ADH). The potassium level in these situations is normal, because adrenal production of aldosterone is not dependent on the pituitary.

A pituitary disease is a disorder primarily affecting the pituitary gland.

The main disorders involving the pituitary gland are:

Overproduction or underproduction of a pituitary hormone will affect the respective end-organ. For example, insufficient production (hyposecretion) of thyroid stimulating hormone (TSH) in the pituitary gland will cause hypothyroidism, while overproduction (hypersecretion) of TSH will cause hyperthyroidism. Thyroidisms caused by the pituitary gland are less common though, accounting for less than 10% of all hypothyroidism cases and much less than 1% of hyperthyroidism cases.

Symptoms include rapid weight gain, particularly of the trunk and face with sparing of the limbs (central obesity). Common signs include the growth of fat pads along the collarbone, on the back of the neck ("buffalo hump" or lipodystrophy), and on the face ("moon face"). Other symptoms include excess sweating, dilation of capillaries, thinning of the skin (which causes easy bruising and dryness, particularly the hands) and mucous membranes, purple or red striae (the weight gain in Cushing's syndrome stretches the skin, which is thin and weakened, causing it to hemorrhage) on the trunk, buttocks, arms, legs, or breasts, proximal muscle weakness (hips, shoulders), and hirsutism (facial male-pattern hair growth), baldness and/or extremely dry and brittle hair. In rare cases, Cushing's can cause hypocalcemia. The excess cortisol may also affect other endocrine systems and cause, for example, insomnia, inhibited aromatase, reduced libido, impotence in men, and amenorrhoea/oligomenorrhea and infertility in women due to elevations in androgens. Studies have also shown that the resultant amenorrhea is due to hypercortisolism, which feeds back onto the hypothalamus resulting in decreased levels of GnRH release.

Cognitive conditions, including memory and attention dysfunctions, as well as depression, are commonly associated with elevated cortisol, and may be early indicators of exogenous or endogenous Cushing's. Depression and anxiety disorders are also common.

Other striking and distressing skin changes that may appear in Cushing's syndrome include facial acne, susceptibility to superficial fungus (dermatophyte and malassezia) infections, and the characteristic purplish, atrophic striae on the abdomen.

Other signs include increased urination (and accompanying increased thirst), persistent high blood pressure (due to cortisol's enhancement of epinephrine's vasoconstrictive effect) and insulin resistance (especially common with ACTH production outside the pituitary), leading to high blood sugar and insulin resistance which can lead to diabetes mellitus. Insulin resistance is accompanied by skin changes such as acanthosis nigricans in the axilla and around the neck, as well as skin tags in the axilla. Untreated Cushing's syndrome can lead to heart disease and increased mortality. Cortisol can also exhibit mineralocorticoid activity in high concentrations, worsening the hypertension and leading to hypokalemia (common in ectopic ACTH secretion). Furthermore, excessive cortisol may lead to gastrointestinal disturbances, opportunistic infections, and impaired wound healing related to cortisol's suppression of the immune and inflammatory responses. Osteoporosis is also an issue in Cushing's syndrome since osteoblast activity is inhibited. Additionally, Cushing's syndrome may cause sore and aching joints, particularly in the hip, shoulders, and lower back. Cushing’s syndrome includes all the causes of increased cortisol leading to the diseased state. Cushing’s disease is a specific type of Cushing’s syndrome caused by a pituitary tumor leading to excessive production of ACTH (adrenocorticotropic hormone). Excessive ACTH stimulates the adrenal cortex to produce high levels of cortisol, producing the disease state. Cushing's disease due to excess ACTH may also result in hyperpigmentation. This is due to Melanocyte-Stimulating Hormone production as a byproduct of ACTH synthesis from Pro-opiomelanocortin (POMC). Alternatively, it is proposed that the high levels of ACTH, β-lipotropin, and γ-lipotropin, which contain weak MSH function, can act on the melanocortin 1 receptor. A variant of Cushing's disease can be caused by ectopic, i.e. extrapituitary, ACTH production from, for example, a small-cell lung cancer. When Cushing's syndrome is caused by an increase of cortisol at the level of the adrenal glands (via an adenoma or hyperplasia), negative feedback ultimately reduces ACTH production in the pituitary. In these cases, ACTH levels remain low and no hyperpigmentation develops. While all Cushing’s disease gives Cushing’s syndrome, not all Cushing’s syndrome is due to Cushing’s disease.

Brain changes such as cerebral atrophy may occur. This atrophy is associated with areas of high glucocorticoid receptor concentrations such as the hippocampus and correlates highly with psychopathological personality changes.

- Rapid weight gain

- Moodiness, irritability, or depression

- Muscle and bone weakness

- Memory and attention dysfunction

- Osteoporosis

- Diabetes mellitus

- Hypertension

- Immune suppression

- Sleep disturbances

- Menstrual disorders such as amenorrhea in women

- Decreased fertility in men

- Hirsutism

- Baldness

- Hypercholesterolemia

Acromegaly is a disorder that results from excess growth hormone (GH) after the growth plates have closed. The initial symptom is typically enlargement of the hands and feet. There may also be enlargement of the forehead, jaw, and nose. Other symptoms may include joint pain, thicker skin, deepening of the voice, headaches, and problems with vision. Complications of the disease may include type 2 diabetes, sleep apnea, and high blood pressure.

Acromegaly is typically due to the pituitary gland producing too much growth hormone. In more than 95% of cases the excess production is due to a benign tumor, known as a pituitary adenoma. The condition is not inherited from a person's parents. Rarely acromegaly is due to tumors in other parts of the body. Diagnosis is by measuring growth hormone after a person has drunk glucose or by measuring insulin-like growth factor I in the blood. After diagnosis, medical imaging of the pituitary is carried out to look for an adenoma. If excess growth hormone is produced during childhood the result is gigantism.

Treatment options include surgery to remove the tumor, medications, and radiation therapy. Surgery is usually the preferred treatment and is most effective when the tumor is smaller. In those in whom surgery is not effective, medications of the somatostatin analogue or GH receptor antagonist type may be used. The effects of radiation therapy are more gradual than that of surgery or medication. Without treatment those affected live on average 10 years less; however, with treatment life expectancy is typically normal.

Acromegaly affects about 6 per 100,000 people. It is most commonly diagnosed in middle age. Males and females are affected with equal frequency. The first medical description of the disorder occurred in 1772 by Nicolas Saucerotte. The term is from Greek "akron" meaning "extremity" and "mega" meaning "large".

Hormone secreting pituitary adenomas cause one of several forms of hyperpituitarism. The specifics depend on the type of hormone. Some tumors secrete more than one hormone, the most common combination being GH and prolactin, which present as unexpected bone growth and unexpected lactation (in both men and women).

A patient with pituitary adenoma may present with visual field defects, classically bitemporal hemianopsia. It arises from the compression of the optic nerve by the tumor. The specific area of the visual pathway at which compression by these tumours occurs is at the optic chiasma.

The anatomy of this structure causes pressure on it to produce a defect in the temporal visual field on both sides, a condition called bitemporal hemianopsia. If originating superior to the optic chiasm, more commonly in a craniopharyngioma of the pituitary stalk, the visual field defect will first appear as bitemporal inferior quadrantanopia, if originating inferior to the optic chiasm the visual field defect will first appear as bitemporal superior quadrantanopia. Lateral expansion of a pituitary adenoma can also compress the abducens nerve, causing a lateral rectus palsy.

Also, a pituitary adenoma can cause symptoms of increased intracranial pressure.

Prolactinomas often start to give symptoms especially during pregnancy, when the hormone progesterone increases the tumor's growth rate.

Various types of headaches are common in patients with pituitary adenomas. The adenoma may be the prime causative factor behind the headache or may serve to exacerbate a headache caused by other factors. Amongst the types of headaches experienced are both chronic and episodic migraine, and more uncommonly various unilateral headaches; primary stabbing headache, short-lasting unilateral neuralgiform headache attacks with conjunctival injection and tearing (SUNCT) - another type of stabbing headache characterized by short stabs of pain -, cluster headache, and hemicrania continua (HS).

Non-secreting adenomas can go undetected for an extended time because no obvious abnormalities are seen; the gradual reduction in normal activities due to decreased production of hormones is rather less evident. For example, insufficient adrenocorticotropic hormone means that the adrenal glands will not produce sufficient cortisol, resulting in slow recovery from illness, inflammation and chronic fatigue; insufficient growth hormone in children and adolescents leads to diminished stature but which can have many other explanations.

Various psychiatric manifestations have been associated with pituitary disorders including pituitary adenomas. Psychiatric symptoms such as depression, anxiety apathy, emotional instability, easy irritability and hostility have been noted.

The symptoms due to a prolactinoma are broadly divided into those that are caused by increased prolactin levels or mass effect.

Those that are caused by increased prolactin levels are:

- Amenorrhea (disappearance of ovulation periods)

- Galactorrhea (Milk production; infrequent in men)

- Loss of axillary and pubic hair

- Hypogonadism (Reduced function of the gonads.)

- Gynecomastia (an increase in male breast size)

- Erectile dysfunction (in males)

Those that are caused by mass effect are:

- Bitemporal hemianopsia (due to pressure on the optic chiasm)

- Vertigo

- Nausea, vomiting

In the developed world it is a rare complication of pregnancy, usually occurring after excessive blood loss. The presence of disseminated intravascular coagulation (i.e., in amniotic fluid embolism or HELLP syndrome) also appears to be a factor in its development.

Cushing's syndrome is a collection of signs and symptoms due to prolonged exposure to cortisol. Signs and symptoms may include high blood pressure, abdominal obesity but with thin arms and legs, reddish stretch marks, a round red face, a fat lump between the shoulders, weak muscles, weak bones, acne, and fragile skin that heals poorly. Women may have more hair and irregular menstruation. Occasionally there may be changes in mood, headaches, and a chronic feeling of tiredness.

Cushing's syndrome is caused by either excessive cortisol-like medication such as prednisone or a tumor that either produces or results in the production of excessive cortisol by the adrenal glands. Cases due to a pituitary adenoma are known as Cushing's disease. It is the second most common cause of Cushing's syndrome after medication. A number of other tumors may also cause Cushing's. Some of these are associated with inherited disorders such as multiple endocrine neoplasia type 1 and Carney complex. Diagnosis requires a number of steps. The first step is to check the medications a person takes. The second step is to measure levels of cortisol in the urine, saliva or in the blood after taking dexamethasone. If this test is abnormal, the cortisol may be measured late at night. If the cortisol remains high, a blood test for ACTH may be done to determine if the pituitary is involved.

Most cases can be treated and cured. If due to medications, these can often be slowly stopped. If caused by a tumor, it may be treated by a combination of surgery, chemotherapy, and/or radiation. If the pituitary was affected, other medications may be required to replace its lost function. With treatment, life expectancy is usually normal. Some, in whom surgery is unable to remove the entire tumor, have an increased risk of death.

About two to three people per million are affected each year. It most commonly affects people who are 20 to 50 years of age. Women are affected three times more often than men. A mild degree of overproduction of cortisol without obvious symptoms, however, is more common. Cushing's syndrome was first described by Harvey Cushing in 1932. Cushing's syndrome may also occur in other animals including cats, dogs, and horses.

Syndrome of inappropriate antidiuretic hormone secretion (SIADH) is characterized by excessive unsuppressible release of antidiuretic hormone (ADH) either from the posterior pituitary gland, or an abnormal non-pituitary source. Unsuppressed ADH causes an unrelenting increase in solute-free water being returned by the tubules of the kidney to the venous circulation.

ADH is derived from a preprohormone precursor that is synthesized in cells in the hypothalamus and stored in vesicles in the posterior pituitary. "Appropriate" ADH secretion is regulated by osmoreceptors on the hypothalamic cells that synthesize and store ADH: plasma hypertonicity activates these receptors, ADH is released into the blood stream, the kidney increases solute-free water return to the circulation, and the hypertonicity is alleviated. "Inappropriate" ADH secretion causes a "unrelenting increase" in solute-free water ("free water") absorption by the kidneys, with two consequences. First, in the extracellular fluid (ECF) space, there is a dilution of blood solutes, causing hypoosmolality, including a low sodium concentration - hyponatremia. Then virtually simultaneously, in the intracellular space, cells swell, i.e. intracellular volume increases. Swelling of brain cells causes various neurological abnormalities which in severe or acute cases can result in convulsions, coma, and death.

The causes of SIADH are grouped into six categories: 1) central nervous system diseases that directly stimulate the hypothalamus, the site of control of ADH secretion; 2) various cancers that synthesize and secrete ectopic ADH; 3) various pulmonary diseases; 4) numerous (at least seventeen) drugs that chemically stimulate the hypothalamus; 5) inherited mutations that cause aquaporins always to be "turned on"; and 6) miscellaneous largely transient conditions.

Potential treatments of SIADH include restriction of fluid intake, correction of an identifiable reversible underlying cause, and/or medication which promotes solute-free water excretion by the kidney. The presence of cerebral edema may necessitate intravenous isotonic or hypertonic saline administration.

SIADH was originally described in 1957 in two people with small-cell carcinoma of the lung.