Clinical Highlights Flashcards
Hypopituitarism is rare, what is the most common cause?
• what are some other causes?
MOST COMMON: Tx for pituitary Tumor
Other Causes: mass lesions pituitary surgery pituitary radiation infiltrative lesions infarction => Sheehan syndrome Apoplexy
T or F: growth hormone levels cannot be used in the diagnosis of GH disorders
True, you need to check IGF-1
What are some syndromes that could be associated with GH adenoma?
- MEN1
- Familial Acromegaly
- McCune Albright Syndrome
T or F: most patients with GH ademoma present with a MACROadenoma.
TRUE, 75% of patients present with this.
*Because its large it may compress other tissue
How do you diagnose Acromegaly?
- SCREEN:
• IGF-1 (sensitive, but not specific to GH) - IF IGF-1 is elevated:
• Oral Glucose Tolerance Test - IF GH>2ng/mL after the test then you have acromegaly (b/c GH isn’t responding the way it should to hyperglycemia)
- IMAGING must be done last
How do you treat Acromegaly?
SURGERY if possible
If not possible then octreotide (somatostatin)
Who most commonly presents with a prolactinoma?
Women around 30 years old who is asymptomatic or may have hypogonadism, menstrual abnormalities, infertility, galactorrhea or bone loss => increase in incidence in pregnancy
Note: prolactinomas are the most common cause of prolactinemia
How do you diagnose a prolactinoma?
Prolactin >250 ug/L is very indicative (NL is less than 25 ug/L)
Over 500 ug/L is DIAGNOSTIC
the only thing that could change this is use of antipsychotics that suppress dopamine
What is the treatment for prolactinomas?
DOPAMINE Agonists
• Bromocriptine
• Cabergolin
What is typically the clinical manifestation of hypothalamic lesions?
Diabetes Insipidus (by disrupting ADH)
What are 4 general reasons that you might get SIADH?
- Paraneoplastic
- Brain
- Drugs (nicotine, thiazides, vincas, MAOIs)
- Other (Post-op, Hypothyroid, Glucocorticoid insufficiency)
How do people with SIADH present?
Na less than 125
N/V/HA
Na less than 120
Seizure, coma, respiratory arrest
How do you diagnose SIADH?
Euvolemic (no edema, ascites) hyponatremia (defined as Na < 136), with INAPPROPRIATELY CONCENTRATED urine
What is the treatment of SIADH?
- Remove underlying cause
- Restrict H2O
- Demeclocycline, Vaptans, Lithium
- Hypertonic Saline (risky)
What are some causes of nephrogenic diabetes insipidus?
Renal Dz Hypercalcemia Hypokalemia Lithium (messes up glycogen synthase kinase so that ATP can't be made for conversion to cAMP to release AQP2) Cyclophosphamide, Cisplatin
What are some causes of neurogenic Diabetes Insipidus?
WATER DEPRIVATION TESTDO NOT MEASURE ADH**
Restrict Smoking and Overnight H2O
IF urine is still dilute then DI
IF DI then give SQ ADH and check urine
IF urine concentrates then NEUROgenic
IF urine does not concentrate then NEPHROgenic
What is the normal plasma osmolality?
290-295 (so NL serum sodium should be about half of that between 136 and 145)
ADH is stimulated around 280
Thrist onset is at 297
T or F: CHF and pregnancy can cause elevated ADH.
TRUE
What HLA types are associated with T1DM?
HLA-DR3 and 4 (these are found on chromosome 6)
Defects in CTLA-3 and PTPN22 are also possible risk factors
What antibodies are associated with T1DM?
Anti-GAD
Anti-ICA512
What are the phases in the development of T1DM?
- Some kind of environmental insult of ß-cells in the setting of genetic predisposition
- Loss of 1st phase in insulin secretion
- Loss of Tolerance in OGTT
- Overt DM + C-peptide
- Over DM without C-peptide
What are normal and DM levels of:
Fasting glucose
Oral GTT
HbA1c
NL/DM
FG - less than 100/over 126
OGTT - less than 140/over 200
HbA1C - less than 5.6/over 6.5
Any random BG test above 200 is dx of DM
Anything between is DM
What is the #1 environmental risk factor for T2DM?
Central Obesity
How are the following affected in T2DM? •Amylin • GLP-1 • Glucagon • SGLT-2
Amylin - not secreted after meals to reduce glucagon and gastric emptying
GLP-1 - reduced so less stimulation of insulin release
Glucagon - does not fall after meals
SGLT-2 - resorbs 2x as much glucose (2mg/lb/day)