Hypopituitarism

Hypopituitarism describes either a partial or complete deficiency of pituitary hormones. 

Causes:

• Pituitary adenoma 
• Macroadenomas (>1cm) cause a hormone deficit in 30% of cases
• Microadenomas (<1cm) rarely affect pituitary function but those producing prolactin may cause hypogonadism due to its suppressive effects on FSH and LH secretion
• Radiotherapy
• Surgery 
• Peri-pituitary lesions 
• Craniopharyngioma 
• Meningioma 
• Optic nerve glioma 
• Metastatic lesions 
• Infiltrative conditions 
• Sarcoidosis 
• Histiocytosis X
• Primary haemochromatosis
• Infections 
• TB
• Syphilis
• Head injury 
• SAH 
• Sheehan’s syndrome 
• Pituitary apoplexy

Signs and symptoms of pituitary insufficiency depend on the hormones affected: 

• Lack of growth hormone
• Decreased energy 
• Muscle weakness
• Lack of ACTH (= secondary adrenal insufficiency)
• Fatigue 
• Weakness
• Anorexia 
• Weight loss 
• Nausea and vomiting 
• Abdominal pain 
• Hypoglcaemia 
• Decreased bone mineral density 
• Loss of axillary and pubic hair
• Lack of Gonadotrophins 
• Erectile dysfunction 
• Reduced muscle mass
• Oligo/amenorrhoea
• Lack of TSH (= secondary hypothyroidism)
• Fatigue 
• Dry skin
• Cold intolerance 
• Constipation 
• Weight gain
• Lack of antidiuretic hormone (= cranial diabetes insipidus)
• Polyuria
• Polydipsia

Management 

• Treat cause 
• Replace hormones as needed

References

Prabhaker, V. and Shalet, S. Aetiology, diagnosis and management of hypopituitarism in adult life. Postgrad Med j. 2006; 82(966): 259-266.

 The Pituitary Foundation.  GP factsheet.  Available at http://www.pituitary.org.uk/content/view/482/249/