Endocrine and metabolic complications of advanced cancer Flashcards
1
Q
Cushing’s Syndrome
A
- paraneoplastic syndrome from ectopic ACTH secretion
- lung cancer most common
- thymoma, pancreatic islet ca
- Hypercortisolism
- osteoporosis
- hypertension
- facial plethora
- stria
- muscle weakness
- bruising
- glucose intolerance
- weight loss
2
Q
Diagnosis of Cushing’s syndrome
A
- 24 urinary cortisol (x3 ULN)
- overnight dex suppression test
- am cortisol < 50
3
Q
treatment of Cushing’s syndrome secondary to ectopic ACTH
A
- tumour resection
- medications to inhibit synthesis of cortisol
- ketoconazole
- metyrapone
- mitotane
- octreotide
- mifepristone
- monitor with 24 hour urinary cortisol
- will require homone replacement therapy
- steroids for mineralocorticoid replacement
4
Q
SIAD (definition)
A
- concentrated urine and hypoosmolar and hyponatremic plasma
- abnormal free water excretion by kidneys
- inapppropriate antidiuresis
5
Q
Pathophysiology of SIAD
A
- ADH acts on kidneys
- absorbs water but loses sodium in urine
Etiology
- CNS causes (infection, bleeding, MS)
-
Cancer (ectopic ADH)
- (small cell, mesothelioma, GI, GU, sarcoma, lymphoma)
- Drugs
- carbamazepine
- valproic acid
- SSRI
- morphine
- Amitriptyline
- Sarcoidosis
- Pulmonary causes
- Pneumonia
- abscess
- asthma, CF
6
Q
Clinical presentation of SIAD
A
- hyponatremia
- confusion, coma, seizure
- depends on rate of decline
7
Q
Diagnosis of SIAD
A
EUVOLEMIC hyponatremia from AHD from posterior pituitary
ADH secretion increases water absorption from kidneys –> dilution of sodium in body —> hypoosmolar hyponatremia
Diagnosis
- hypoosmolar hyponatremia
- plasma osm < 275, plasma Na < 135
- HIGH urinary sodium and osmo
- urine osmo > 100, urine Na > 20 mEq/L
PLASMA : LOW OSMO, LOW NA
URINE : HIGH osmo, HIGH Na
- may correct with fluid restriction
- will not correct with IV fluids
- water load test :
- give 20 ml/kg water load
- normal to excrete > 90 % in 4 hours
- normal to dilute urine to osmo < 100
- if those don’t occur: SIAD
8
Q
SIAD treatment
A
- Acute:
- CNS sx
- hypertonic saline
- correction 0.5 mmol/L/ HOUR
- Go slowly
- Chronic
- fluid restriction 500 ml/day
- target urine output < 500 ml/day
- go slow to avoid demyelination
- not practical for comfort in pall care
- Other
- demeclocycline
- tolvaptan (ADH receptor antagonist)
- Urea (increases free water excretion)
9
Q
Hypoglycemia
A
- common with pancreatic islet cell tumours (secrete insulin)
- can occur in other tumours
- retroperitoneal, intrathoracic large tumours
- secrete abnormal IGF-2 that binds to insulin receptors, cause hypoglycemia
10
Q
Hypoglycemia symptoms/ presentation
A
- confusion
- agitation
- coma
- seizure
- tremours
- nausea
- malaise
- often following exercise or fasting
11
Q
Investigations for hypoglycemia
A
- insulin levels (low)
- C peptide (low)
- reviews meds for other causes
- liver failure (impaired gluconeogenesis)
12
Q
Hypoglycemia treatment
A
- IV d50W x 1 amp
- debulking surgery / chemo
- steroids
- glucagon
- frequent feeding
13
Q
Features and common sites of insulinomas
A
- neuroglycopenia
- beta islet cell tumours of pancreas
- MEN tumours
14
Q
Palliative therapy for insulinomas
A
- frequent feeding
- IV glucose
- Diazoxide + HCTZ
- Octreotide
15
Q
Gastrinoma : features and common sites
Zollinger-Ellison syndrome
A
- peptic ulceration
- diarrhea, weight loss, malabsorption
- gastric dumping
- pancreas
- duodenum
