Disorders of Anterior Pituitary: Acromegaly, Sheehan Syndrome

Hormones that control growth, physical and sexual development, and other endocrine glands are released by the anterior (front) lobe of the pituitary gland. Other endocrine glands will over- or under-produce particular hormones as a result of the anterior lobe of the pituitary gland's over- or under-secretion of certain hormones.

Read this blog further to get a quick overview of this important topic for medicine and ace your NEET PG exam preparation.

Acromegaly

It occurs due to excess Growth hormone (GH) after puberty. Somatotrophs also known as growth hormones are most  abundant cells present  in the pituitary.

Causes of Acromegaly are :

• Somatotroph adenoma leading to increase in growth hormones.
• Mixed Mammosomatotroph adenoma- in this Growth hormone increases and also there is increase in Prolactin levels which  lead to galactorrhoea and hypogonadism.
• Hypothalamic hamartoma (increase in GHRH), choristoma
• Extra pituitary GNRH source- Carcinoid tumor
• Intra pituitary GNRH source- Ectopic pituitary tissue (present in the nasopharynx can be presented by carcinoma) and Pancreatic tumor

Clinical Feature of Acromegaly

• Cardiomegaly 
• Acral enlargement:
  • Increase in size of Hands and Feet.
  • Increase in Finger thickness leading to spade-like hands. The ring gets impacted.
  • Glove size increases.
  • Shoe size increases.
• Facial feature:
  • Frontal bossing
  • Large fleshy nose
  • Coarse faces
  • Hyperhidrosis (increase in sweating)
  • Increased sebum excretion
  • Widened space between the lower incisors which  is also termed as Prognathism.
• Height is the same as it occurs after puberty. Whereas the Heel pad thickness increases (Radiological parameters) that is More than 25 mm.
• Arthropathy, kyphosis, carpal tunnel syndrome.
• Cardiomyopathy: Risk of arrhythmia in the patients (a most common cause of mortality), cardiovascular complications.
• Tongue size is relatively bigger leading to obstructive sleep apnoea.
• Colonic polyps and malignancy can develop.
• Impaired glucose tolerance- Increase in growth hormone leads to increased sugar levels causing diabetes mellitus. Fasting blood sugar level is 100 – 125 mg % (impaired fasting glucose) and 2-hour value is 140 – 199 mg % (Impaired glucose tolerance).
• Hypertension
• Rare findings- Galactorrhoea and Visual field defects: That is bitemporal hemianopia.

Diagnosis of Acromegaly 

• Screening of insulin-like growth factor 1 (IGF-1) which increases in acromegaly. It is used for postnatal growth.
• Investigation of choice is an oral glucose intolerance test. In normal individuals 75 grams of glucose suppresses the growth hormone. Failure to suppress growth hormone (less than 0.4 ųg/liters) can help us to diagnose acromegaly.
• Prolactin levels increased.
• TSH is normal or may be suppressed.
• MRI head: To localize the pituitary adenoma (anterior pituitary more than 10 mm)
• Heel pad thickness (more than 25 mm) is used to check the progression of the disease.

Management of Acromegaly

• Treatment of choice is Trans-sphenoidal surgery.
• Preoperatively to shrink the tumor Somatostatin receptor ligand analogs are given:
  • Octreotide
  • Lanreotide
  • Pasireotide 

These drugs act by blocking the SSTR 2 and SSTR 5 receptors which are receptors for growth hormones thus help in decreasing growth hormone production. These drugs show significant improvement and are given in the form of Monthly injections as prescribed.

After surgery, the first thing that improves is soft tissue swelling immediately. Aggressive surgery in patients leads to hypopituitarism. In less aggressive surgery, recurrence of tumor can occur.

PEGVISOMANT is given in the case of recurrence or  if poor response to somatostatin receptor ligand analogues. It blocks the growth hormone receptors thus helping in reducing the growth hormone level.

Sheehan Syndrome

• It is an anterior pituitary defect that leads to panhypopituitarism. In this syndrome Growth hormones are first to fall. It also Results in hypoglycemia, emotional lability, mood swings and Post-partum blues
• ACTH decreases lead to a decrease in cortisol causing a decrease in blood sugar levels thus it worsens pre-existing hypoglycemia.
• Prolactin decreases leading to failure of lactation.
• LH hormone decreases lead to secondary amenorrhea and infertility.
• FSH hormone decreases.
• TSH decreases and thus leads to secondary. In this condition T₃, T₄, TSH all are decreased. Patient Presents with clinical manifestation as:
  • Weight gain 
  • Constipation
  • Alopecia
  • Myxedema

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Diagnosis of Sheehan Syndrome

• MRI head: In this we can find  Anterior pituitary destruction.

Management of Sheehan Syndrome:

• Dexamethasone Is the first drug  to be supplemented. It replaces cortisol deficiency and stabilizes the blood sugar levels.
• Combined oral contraceptives are given which is a combination of  estrogen and progesterone. Side effects of progesterone cause withdrawal bleeding thus it helps to treat amenorrhea caused and it  is gender specific.
• Levothyroxine

Simmonds Disease

It is the cause of non-obstetric damage occurring to the anterior pituitary. It is mainly seen in patients with hypertension and sickle cell disease.

Hypopituitarism

It implies only when there is growth hormone. It is Seen mainly  in the pediatric population.

Clinical Features

• Present since birth (developmental defects)
• Short stature (height less than 3 centiles)
• Shrill voice 
• Doll-like Facies

Investigations

Investigation of choice is Insulin tolerance test / Arginine challenge test. Insulin tolerance tests are slightly risky because it triggers hypoglycemia.

Treatment

Growth hormone  injections (DNA Recombinant technology) are given  till Puberty.

Prolactinoma

It is the most common Functioning pituitary tumor. Overall most common Pituitary Tumor is a non-functioning Tumor. Prolactin has an inhibitory effect on LH and FSH.

Clinical Features

• In Females- Anovulation, Amenorrhoea and Secondary infertility can be seen due to decrease in LH and FSH.
• In males- Galactorrhoea can be found which is mainly associated with increase of prolactin.
• Bitemporal hemianopia- Defect in optic chiasma. It is mainly associated with increased size of adrenal gland.

Investigation

• Raised Serum Prolactin levels
• MRI head

Treatment

• Bromocriptine/cabergoline (Long acting)
• Surgery is rarely needed.
• Medical management is best.

Empty Sella Syndrome

A rare disorder known as empty sella syndrome (ESS) causes problems with the contents of the sella turcica, causing your pituitary gland to flatten or shrink. Your pituitary gland is surrounded and shielded by the sella turcica, a bony structure at the base of your brain.

A saddle-like chamber called the sella turcica. The Latin term for it is "Turkish seat." Hormonal imbalances, recurrent headaches, and changes in eyesight are some of the symptoms of ESS.

A little gland called the pituitary is situated beneath the hypothalamus at the base of the brain. It is a component of your endocrine system and is responsible for producing a wide range of critical hormones. These hormones have an impact on and regulate many endocrine glands in your body.

Symptoms of Empty Sella Syndrome

Chronic headaches are arguably the most typical symptom of empty sella syndrome (ESS). Researchers are unsure, meanwhile, whether headaches are a direct result of ESS or merely coincidental. Numerous ESS sufferers have high blood pressure (hypertension), which, in severe cases, can also result in headaches.

Due to pituitary gland damage from ESS, hormonal abnormalities are frequently experienced. Depending on whatever hormone(s) are impacted, people with ESS may have a variety of symptoms. Any of the symptoms listed below could indicate ESS:

• Irregular discharge from the nipples (galactorrhea).
• Erection problems.
• Periods that are irregular or don't occur at all (amenorrhea).
• Reduced or absent sex desire (low libido).
• Fatigue

Rarely, those who have empty sella syndrome may exhibit the following signs and symptoms:

• Elevated benign intracranial pressure inside their skull.
• Cerebrospinal rhinorrhea is the term for cerebrospinal fluid leakage from the nose.
• Increased cranial pressure-related swelling of the optic disc (papilledema).
• Eyesight alterations, such as a reduction in eyesight clarity.

Causes of empty sella syndrome

The empty sella syndrome is caused either due to primary empty sella or secondary empty sella

Causes of primary empty sella

Primary empty sella (PES) is a condition when your pituitary gland is pressed against the sella turcica by one of the arachnoid layers covering the surface of your brain.

Primary empty sella syndrome's actual cause is still a mystery to medical professionals.

According to one idea, primary empty sella develops when there is a chance that cerebrospinal fluid will enter the sella turcica and flatten your pituitary gland due to a congenital abnormality in the tissue lining your brain. While the pituitary gland itself may be difficult to spot on an imaging scan, it almost always functions normally and prevents empty sella syndrome in these circumstances.

Causes of secondary empty sella

When your pituitary gland or the sella turcica is somehow harmed as a result of another condition or incident, secondary empty sella (SES) occurs. Due to this, a variety of factors might result in SES. The following are the common causes of damage:

• A growth
• Radiation treatment
• Surgery on the pituitary gland area of the brain.
• Traumatic brain damage is one example of head trauma.
• Brain cancer
• Idiopathic intracranial hypertension (IIH): CSF (cerebrospinal fluid) buildup around the brain can result in IIH, which is increased pressure inside the skull. Your pituitary gland may get compressed as a result of this added pressure.
• Pituitary tumors A growth or tumor on your pituitary gland is known as a pituitary adenoma. They are frequently benign (non-cancerous).

Diagnosis of empty sella syndrome

The following imaging techniques are used by providers to diagnose ESS:

• A brain CT (computed tomography) scan produces precise images of your brain and pituitary gland using X-rays and a computer.
• A brain MRI (magnetic resonance imaging) uses radio waves and powerful magnets to produce precise images of specific organs, tissues, and body parts, including the sella turcica.

To evaluate your hormone levels, your doctor could request additional testing, such as blood tests. Occasionally, medical professionals may carry out the following procedures to see if your brain has increased pressure:

An ophthalmologist will examine your retina, the layer of tissue at the back of your eye.

Spinal tap (lumbar puncture).

If your doctor did imaging tests and found an empty sella but your pituitary gland is still functioning correctly, you won't need therapy. This is the condition most frequently.

Treatment of empty sella syndrome

Empty sella syndrome (ESS), which impairs pituitary gland function, is typically treated with medication that corrects abnormal hormone levels, depending on which hormones are involved.

If ESS is producing cerebrospinal fluid (CSF) rhinorrhea, you could need surgery to repair your sella turcica.

Adrenal Crisis

When adrenal glands don't produce enough of the hormone cortisol, person suffers from  adrenal crisis. It is a potentially fatal side effect of Addison's disease (adrenal insufficiency). 

Almost every organ and tissue in your body is impacted by cortisol. Some of its features are:

• Controlling the stress reaction in your body.
• Assisting in metabolic regulation.
• Stopping the inflammation.
• Blood pressure control.
• Control of blood sugar.
• Assisting in regulating your sleep-wake cycle.

Causes of adrenal crisis

An adrenal crisis could be brought on by the stimuli listed below:

• Not receiving treatment for a condition like Addison's disease that causes adrenal insufficiency.
• Damage to your adrenal gland, such as diseases or operations.
• Dehydration
• Hypopituitarism
• Infection
• After a prolonged period of use, stopping taking glucocorticoid medicines (prednisone).
• Burden on the mind or the spirit.

Symptoms of Adrenal Crisis

• Pain in your belly or your side (flank)
• Chronic tiredness
• Decrease in appetite
• Skin that has darker spots (hyperpigmentation).
• Weakness
• Loss of weight without cause.
• Dehydration
• Diarrhea
• Dizziness, bewilderment, feeling dizzy or in a coma.
• Fever
• Headache
• Joint discomfort
• Low glucose levels
• A low blood pressure
• Vomiting and nauseous
• Respiratory rate: rapid breathing
• Quick heartbeat

Diagnosis of Adrenal Crisis

Many of the symptoms are similar to those of other prevalent diseases, an adrenal crisis may be challenging to identify. However, the subsequent examinations can assist your doctor in correctly diagnosing an adrenal crisis:

• Blood test for the hormone adrenocorticotropic (ACTH).
• Testing for blood sugar
• Test for cortisol
• Blood pH test
• Blood test for potassium
• Blood test for sodium

Treatment of Adrenal Crisis

An intravenous (IV) injection of hydrocortisone (hydrocortisone phosphate or hydrocortisone sodium succinate) and saline solution will be given by your healthcare practitioner right away into a vein in your arm or hand. Cortisol is replaced by the injection of hydrocortisone.

Your healthcare professional may prescribe antibiotics if a bacterial infection is the root cause of your adrenal crisis.

Any further symptoms of your adrenal crisis may also be treated by your healthcare provider. Water, sports drinks, or coconut water may be used as therapies for electrolyte imbalance or dehydration. Treatment for hypoglycemia may involve eating carbs.

Your healthcare professional will do ACTH stimulation tests to identify the cause of your adrenal crisis if you have never experienced one before.

Addison's disease

When the adrenal cortex is harmed and the adrenal glands don't produce enough cortisol and aldosterone, Addison's disease develops.The body's response to stressful events is controlled by cortisol. Regulation of potassium and sodium is aided by aldosterone. Androgens, or sex hormones, are also produced by the adrenal cortex.

Symptoms of addison's disease

Following are explained some symptoms of addison's disease

• Muscle aches, fatigue, and exhaustion
• Deepening of the skin tone
• Decrease in weight or appetite
• A drop in blood pressure or heart rate Low blood sugar levels
• Fainting episodes
• Mouth ulcers salt cravings nausea and vomiting
• Angry or depressed mood
• Energy deficits sleep issues
• Agitation 
• Delirium hallucinations both audible and seen

Diagnosis of Addison's Disease

Your medical history and the symptoms you've been having will be discussed with you by your doctor. They will do a physical examination and perhaps request certain laboratory tests to measure your salt and potassium levels.

Treatment of Addison's Disease

Therapy that replaces corticosteroids (steroid) is widely utilised as a method of treatment. Corticosteroid drugs take the place of the aldosterone and cortisol your body no longer produces. It is frequently taken as a pill two or three times a day.

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