pheochromocytoma topic in physiology during first year

1. Amira Zulaikha 082012100065
Nur Amalina 082012100067

2. • Greek "phaios =dark, chroma = color,
kytos =cell, oma = tumor“
• Adrenal medulla secrete catecholamine
• Catecholamines are :
o Epinephrine
o Norepinephrine
o Dopamine

3. Phaeochromocytoma
• Rare neuroendocrine tumours of chromaffin
tissue that secrete catecholamines
• Usually benign and contain large amounts of
epinephrine and norepinephrine
• Responsible for less than 0.1% of hypertension
cases
• 80% of these tumours occur in adrenal medulla
(phaeochromocytoma)
• 20% in the body in sympathetic ganglia
(paragangliomas)

5. • 25% of phaechromocytoma are associated
with inherited disorder. Examples are
• Neurofibromatosis
o Multiple tumors develop from neurilemnal sheath
of nerves
• Von Hippel-Lindau Syndrome
o mutation in the von Hippel–Lindau tumor
suppressor gene on chromosome 3
• MEN(Multiple Endocrine Neoplasia) type 2
o Formation of adenomas in multiple glands

7. Clinical feature
• Hypertension(usually paroxysmal)BP unto
300/200mmHg
• Paroxysms of
– Pallor
– Palpitations
– Sweating
– Headache
– Anxiety

8. • Abdominal pain, vomiting
• Constipation
• Weight loss
• Glucose intolerence
• Increased body temperature and BMR

9. Clinical Test
Estimation of Urinary Excretion of Catecholamines
& their Metabolites
( metanephrine, normetanephrine, dopamine, and vanillylmandelic
acid (VMA) )
• the best method is using a 24-hour urine
collection.
• inconvenient but reliable and specific.
• performed more than once to establish
diagnostic certainty.
• Total urine catecholamines: 14 - 110 mcg/24
hours
• Positive = catecholamine levels exceed double the
upper limit of normal.

10. Imaging tests and scans
• only be performed after the diagnosis of
phaeochromocytoma has been established
with 24-hour urine testing.
• Several types of scans can be used to locate
pheochromocytomas.
– Cross-sectional scans ( yield detailed anatomic
information)
– Computed tomography (CT or CAT scan)
– Magnetic resonance imaging (MRI)

11. Management
• TREATMENT: surgical removal of tumour
• pheochromocytoma patients experience
shock (dangerously low blood pressure) when
catecholamine levels suddenly and
unpredictably drop.
• medical therapy is needed to prepare patient
for surgery

12. • Alpha –blocker render the body less sensitive
to catecholmine surges
• Drugs used are:
o alpha-blocker phenoxybenzamine (Non
competitive antagonist )
o Prazosin
o Doxasin

13. Reference
• Nicki R.Colledge, Brian R.Walker and Stuart
H.Ralston,Davidson’s Principle and Practice of
Medicine, 21st edition,Churchill
Livingstone,2010, page 779
• Prof. A.K. Jain, Textbook of Physiology volume
2, 3rd edition,Avichal Publishing Company,
2007, page 757