Causes of gigantism

Gigantism is not common around us. It is a disease caused by excessive and crazy growth during the growth and development process. People with gigantism are generally about two meters tall or more. People with this disease have a bigger appetite than ordinary people and well-developed muscles. However, their huge body will bring some health burdens to the body and may also cause some physical diseases. So do you know what causes gigantism?

Pathogenesis:

The clinical features of gigantism are due to the persistent overproduction of GH and its target hormone IGF-1. GH secretion is dually regulated by hypothalamic hormones: GH-releasing hormone (GHRH) stimulates GH secretion, while somatostatin (SS) inhibits its secretion.

GH pituitary GH-secreting cell hyperplasia or adenoma, adenocarcinoma. The basic morphological change of the pituitary in patients with hypersecretion is an increase in the number of GH-secreting cells in the pituitary. The most common pathological change is a pituitary GH cell adenoma with clear boundaries but no capsule, and a few are pituitary GH cell hyperplasia. The number and distribution of GH-secreting cells in the non-tumor part of the pituitary were normal. The lesions that cause an increase in pituitary GH cells may be located in the hypothalamus, pituitary gland, or even outside the skull. Most cases of gigantism are caused by primary pituitary tumors.

Clinical manifestations:

Simple gigantism is rare, but more than half of adults develop acromegaly. The clinical manifestations can be divided into two stages.

(I) Early formation stage: The disease mostly occurs in adolescence, and can be as early as a newborn infant. By the age of 10, the child is already as tall as an adult and can continue to grow until about 30 years old. The child can reach a height of 240 cm, with well-developed muscles, extraordinary arm strength, early development of sexual organs, and strong sexual desire. During this period, the basal metabolic rate is high, glucose tolerance is reduced, and it can develop into pituitary diabetes.

(II) Late decline: After reaching the peak of growth, patients gradually begin to decline in their early years, showing symptoms of listlessness, weakness in the limbs, muscle relaxation, kyphosis of the back, hair loss, loss of libido, atrophy of the external genitalia, and often infertility. They also have decreased intelligence, lowered body temperature, reduced metabolic rate, slow heart rate, lower blood sugar, and reduced diabetes. This period lasts about 4 to 5 years, and most patients die young, with an average life expectancy of about 20 years. Due to low resistance, they are prone to die from secondary infections.

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Disease treatment:

Surgery

Suitable for the following patients: 1. Patients with large pituitary tumors that cause obvious compression symptoms, progressive visual field defects, and the risk of blindness. 2. Adenoma undergoes cystic changes or bleeding. 3. Patients whose symptoms progressively worsen and whose vision and visual field progressively deteriorate after radiotherapy. 4. There are signs of intracranial hypertension.

For GH adenomas, although the proportion of drug treatment is increasing, transsphenoidal surgical resection remains the preferred treatment method. The Department of Neurosurgery at Shanghai Huashan Hospital summarized 5 cases of GH adenomas among 42 adolescent pituitary tumor surgeries. Among the 4 male patients, 1 had a microadenoma and 3 had macroadenomas (1 of which was invasive), and 2 were cured. One girl had a microadenoma and was cured [33]. Studies have shown that transsphenoidal surgery can cure 85% of microadenomas and 50% of macroadenomas. The success rate of the surgery increases significantly if the surgery is performed by a surgeon who has extensive experience in transsphenoidal surgery.

Radiation therapy

There are two types: external irradiation and internal irradiation. Growth hormone cells are 60% to 90% sensitive to it and can be used during the formation stage or when activity is progressing. Gigantism can be treated if the height is over 160cm. The indications for radiotherapy are: 1. Patients whose tumors have not been completely removed and whose growth hormone levels are still high; 2. Patients who are elderly and weak and not suitable for surgery, and whose tumors are small and whose growth hormone levels are not significantly elevated. The main side effects are: hypofunction of the anterior pituitary and surrounding target glands, and decreased vision. It is contraindicated for patients with narrowed visual field or high intracranial pressure.

Drug treatment

Drug treatment for gigantism is mainly used for: 1. Those who cannot undergo surgery or are unwilling to undergo surgery; 2. Those who cannot undergo radiotherapy or are unwilling to undergo radiotherapy; 3. Those who have poor results from surgery or radiotherapy or whose disease relapses; 4. Adjuvant treatment. Mainly include: somatostatin analogs, GH receptor antagonists and dopamine agonists, etc.