Nelson Syndrome
Nelson Syndrome
Nelson syndrome is a rare neuroendocrine condition characterized by:
- Aggressive pituitary corticotroph tumor
- Elevated ACTH levels
- Occurs after bilateral adrenalectomy for Cushing's disease
First described by Don Nelson in 1958, it develops in approximately 8-47% of patients post-bilateral adrenalectomy for Cushing's disease.
Key Clinical Manifestations
Primary Features:
- Hyperpigmentation
- Progressive darkening of skin
- Most prominent in sun-exposed areas
- Involves mucous membranes
- Due to high ACTH levels
- Visual Disturbances
- Visual field defects
- Bitemporal hemianopsia
- Diplopia
- Progressive vision loss
- Headaches
- Often severe and progressive
- May be resistant to normal analgesics
- Due to tumor mass effect
Associated Symptoms:
- Neurological Symptoms
- Cranial nerve palsies
- Cavernous sinus invasion symptoms
- Raised intracranial pressure signs
- Hormonal Deficiencies
- Hypopituitarism
- Growth hormone deficiency
- Hypogonadism
- Hypothyroidism
Diagnostic Approach
Laboratory Studies:
- Hormone Levels
- Markedly elevated plasma ACTH (>500 pg/mL)
- Serial ACTH measurements
- Pituitary function tests
- Thyroid function tests
- Other Tests
- Complete blood count
- Electrolytes
- Liver function tests
Imaging Studies:
- MRI Studies
- Contrast-enhanced pituitary MRI
- Regular surveillance imaging
- Assessment of tumor size and invasion
- Visual Assessment
- Visual field testing
- Visual acuity measurement
- Fundoscopic examination
Additional Evaluations:
- Ophthalmological examination
- Neurological assessment
- Quality of life assessment
Treatment Strategies
Primary Treatment Options:
- Surgical Management
- Transsphenoidal surgery
- Transcranial approach if needed
- Decompression of visual pathways
- Tumor debulking
- Radiation Therapy
- Conventional radiotherapy
- Stereotactic radiosurgery
- Gamma knife surgery
- Fractionated radiation
Medical Management:
- Hormone Replacement
- Glucocorticoid replacement
- Mineralocorticoid replacement
- Thyroid hormone if needed
- Sex hormone replacement
- Medical Therapy
- Dopamine agonists
- Somatostatin analogs
- Temozolomide in aggressive cases
Supportive Care:
- Pain management
- Psychological support
- Regular follow-up
- Patient education
Complications and Monitoring
Potential Complications:
- Neurological Complications
- Permanent vision loss
- Cranial nerve palsies
- Hydrocephalus
- Cavernous sinus invasion
- Endocrine Complications
- Permanent hypopituitarism
- Adrenal crisis
- Diabetes insipidus
- Treatment-Related Complications
- Surgical complications
- Radiation-induced hypopituitarism
- Secondary tumors
Monitoring Protocol:
- Regular Follow-up
- ACTH level monitoring
- MRI surveillance
- Visual field testing
- Pituitary function assessment
- Quality of Life Assessment
- Psychological evaluation
- Physical function assessment
- Social support evaluation
Prevention Strategies:
- Early recognition of symptoms
- Proper timing of interventions
- Regular screening post-adrenalectomy
- Patient education about warning signs
