common inpatient endocrine consults william e. clutter, m.d
TRANSCRIPT
Thyroid disorders
Effects of nonthyroidal illness (NTI, “euthyroid sick”) Effects of drugs Hyperthyroidism Hypothyroidism Post-thyroidectomy consults
Nonthyroidal illness (NTI)
Deiodinase inhibition –> decreased T3 TSH suppression T4 & FT4 suppression
NTI: diagnostic problems
Low TSH: NTI vs hyperthyroidism• Clinical signs, including atrial fibrillation• FT4
– Low-normal : probably NTI, especially if TSH >0.1 µU/ml– High: hyperthyroidism
NTI: diagnostic problems Low FT4: NTI vs hypothyroidism
• Clinical signs, eg bradycardia, hypoventilation, hypothermia• TSH
– >20 mU/ml: primary hypothyroidism
– 5-20: primary hypothyroidism vs NTI Repeat in 1-2 weeks or treat empirically and reassess as outpatient
– <5: NTI vs secondary hypothyroidism History or evidence of pituitary disease?
Thyroid function: drug effects
Iodine (amiodarone, X-ray contrast):• Hyperthyoidism
• Hypothyroidism
Amiodarone: inhibits deiodinase• Increased FT4, slightly increased TSH
Lithium: inhibits T4 release -> hypothyroidism Heparin: increases free T4 (in vitro) Furosemide: displaces T4 -> increased FT4
Hyperthyroidism: indications for emergency management
Acute coronary syndrome Heart failure “Thyroid storm”
• fever
• agitation or stupor
• severe concomitant illness
Hyperthyroidism:emergency management
Confirm hyperthyroidism (free T4, TSH)
Propylthiouracil (PTU) 200-300 mg PO Q 6 hr
Iodine (SSKI) 2 gtt (80 mg) PO Q 12 hr
Beta- adrenergic antagonist if not in CHF• propranolol 40 mg Q 6 hr• adjust dose to HR <100/min
Hyperthyroidism:emergency management
Intensive therapy of concomitant disease
Follow free T4 Q 4-6 days
When free T4 normal, schedule RAI therapy• stop iodine 2-4 weeks before• stop PTU 3-5 days before
Hypothyroidism: emergent therapy
Indications: • Hypoventilation
• Bradycardia
• Hypotension
Confirm diagnosis: FT4, TSH T4 50-100 µg IV Q 6 hr x 24 hr, then T4 75-100 µg IV Q 24 hr
Post-thyroidectomy consults Monitor for hypocalcemia Q 12-24 hr Benign disease:
• Subtotal thyroidectomy: start T4; TSH in 6-8 weeks• Lobectomy: T4 or no therapy; TSH in 6-8 weeks
Thyroid carcinoma:• High risk for recurrence:
– hold T4– contact Radiation Oncology– RAI ablation or whole body RAI scan in 2 weeks, then– Start T4
Severe hypercalcemia: signs
Renal:• polyuria, dehydration
• renal failure
Gastrointestinal:• nausea, vomiting, constipation
• abdominal pain
Neurologic:• fatigue, confusion
• coma
Severe hypercalcemia: causes
Malignancy:• Breast carcinoma
• Squamous lung carcinoma, head & neck carcinoma
• Myeloma
• Renal carcinoma
Primary hyperparathyroidism Miscellaneous:
• vitamin D intoxication
• milk-alkali syndrome (calcium carbonate)
Severe hypercalcemia: evaluation
Evidence of cancer• Breast mass; h/o breast cancer• h/o smoking, cough, hemoptysis, mass on CXR• Weight loss, anemia, etc
Evidence of primary hyperparathyroidism• Hypercalcemia for >6 months• h/o renal stones
Plasma [PTH], 25-OH vitamin D • (SPEP, PTH-rP, 1,25-OH D, bone scan)
Severe hypercalcemia: indications for emergency Rx
Severe symptoms of hypercalcemia Plasma [Ca] >12 mg/dl
Severe hypercalcemia: therapy
Restore ECF volume• Normal saline rapidly• Positive fluid balance >2 liters in first 24 hr
Saline diuresis• Normal saline 100-200 ml/hr• Replace potassium
Zoledronic acid 4 mg IV over 15 min• if plasma [Ca] >14 mg/dl or >12 mg/dl after rehydration• Monitor plasma calcium QD
Myeloma or vitamin D toxicity:• prednisone 30 mg BID
Hypocalcemia: clinical signs
Paresthesiae Tetany Trousseau’s, Chvostek’s signs Seizures Chronic: cataracts, basal ganglia Ca
Hypocalcemia: causes
Hypoparathyroidism• Surgical• Autoimmune
• Magnesium deficiency
PTH resistance
Vitamin D deficiency Vitamin D resistance
Other: renal failure, pancreatitis, tumor lysis
Hypocalcemia: evaluation
Confirm low ionized calcium History:
• Neck surgery
• Other autoimmune endocrine disorders
• Causes of Mg deficiency
• GI disorders (malabsorption)
• Family history
Hypocalcemia: evaluation
Physical exam:• Signs of tetany
• Signs of pseudohypoparathyroidism
Lab• PTH, total & ionized calcium
• Creatinine, Mg, P
• (25-OH vitamin D)
Hypoparathyroidism: therapy
IV calcium infusion• 2 gm Ca gluconate (20 ml) IV over 10 min
• 6 gm Ca gluconate/500 cc D5W over 6 hr
• Follow plasma Ca & P Q 4-6 hr & adjust rate
Oral calcium 1-2 gm BID - TID Oral calcitriol 0.25-2 mcg/day
Post-op parathyroidectomy Monitor for hypocalcemia:
• Limited surgery: plasma calcium at discharge & followup• 4-gland exploration: plasma calcium Q 6-12 hr
If hypocalcemia develops, consider:• Hypoparathyroidism• Hungry bone syndrome (elevated alkaline phosphatase)• Vitamin D deficiency
Treat if• Symptomatic or Trousseasu’s positive• Plasma calcium <8 mg/dl
Adrenal disorders
Adrenal failure Post-op adrenalectomy consults Steroid coverage for illness, surgery Severe hypertension, R/O adrenal cause
Adrenal failure: signs
Weakness & fatigue Anorexia & weight loss Nausea & vomiting Lethargy, stupor
Hyponatremia Hypotension Shock & death
Hyperkalemia* Hyperpigmentation*
*Only in primary adrenal failure
Adrenal failure: causes
Primary (cortisol & aldosterone deficient)• AUTOIMMUNE
• tuberculosis, fungal infections
• Hemorrhage, sepsis, etc
Secondary (ACTH & cortisol deficient)• GLUCOCORTICOID THERAPY
• hypothalamic or pituitary lesions
Adrenal failure: evaluation
Dexamethasone 10 mg IV if hypotensive Cortrosyn stimulation test:
• Cortrosyn 250 mcg IV
• Plasma cortisol @ 30 min
• Normal: >20 mcg/dl
• Not sensitive for new onset secondary adrenal failureNot sensitive for new onset secondary adrenal failure– Eg, after pituitary surgery, pituitary apoplexy
– Treat empirically with prednisone for 4 weeks
– Hold prednisone AM of test
Adrenal failure:emergency therapy
Indications:• Hypotension• Stupor• Severe hyperkalemia or hyponatremia
Hydrocortisone 100 mg IV Q 8 hr or dexamethasone 4 mg Q 12 hr
D5/normal saline
Post-op adrenalectomy Cushing’s syndrome due to adrenal adenoma
• Perioperative: hydrocortisone 50 mg IV Q 8 hr• Rapid taper to prednisone 10 mg QAM & 5 mg QPM
Incidentaloma• ? Subclinical Cushing’s syndrome:
– Dexamethasone; Cortrosyn stimulation test
Aldosteronoma• Stop spironolactone; monitor BP, plasma K
Pheochromocytoma• Stop phenoxybenzamine; monitor BP• IV NS for hypotension
Steroid coverage Indications:
• Known adrenal failure• Chronic steroid treatment
• Recent (1 year) chronic steroid treatment
For severe illness, major surgery:• Hydrocortisone 50 mg IV Q 8 hr
For moderate illness, minor surgery• Hydrocortisone 25 mg IV Q 8 hr
Post-op, taper to chronic replacement over 2-3 days
Severe hypertension
Pheochromocytoma Primary hyperaldosteronism Cushing’s syndrome
Evaluation:• Plasma K; if low, plasma aldosterone/PRA
• Plasma catecholamines & metanephrines
• Overnight dexamethasone suppression if clinical signs of Cushing’s syndrome (may be falsely positive)
Sellar or suprasellar mass Pituitary hormone excess
• Prolactin• GH (acromegaly)• ACTH (Cushing’s disease)
Pituitary hormone deficiency• Hypothyroidism, adrenal failure, hypogonadism• Diabetes insipidus
Mass effects• Headache• Visual field loss• Pituitary apoplexy
Incidental finding (10% have microadenomas)
Pituitary disease: evaluation Signs of hormone excess or deficiency Informal visual fields Labs:
• Prolactin• Free T4• Cortrosyn stimulation test• Women: menstrual history; men: plasma testosterone
MRI – pituitary protocol Formal visual fields if mass contacts chiasm
Post-op pituitary surgery
Perioperative steroid coverage Treat pre-operative hypothyroidism, hypogonadism Taper steroids; discharge on prednisone 5 mg QAM If polyuria develops:
• monitor urine output; plasma Na Q 6-12 hr
• Limit fluids to 75-100 cc/hr
• If hypernatremic: DDAVP 1-2 µg SC or IV x 1, then follow urine output
Post-op pituitary surgery
Outpatient followup 4 weeks after discharge• Free T4
• Cortrosyn stimulation test
• Plasma testosterone in men
• Acromegaly: IGF-1
• Cushing’s disease: consider dexamethasone suppression test
Unexpected hypoglycemia
Severe illness• Hepatic failure
• Renal failure
• Sepsis
Sulfonylurea or insulin administration Insulinoma
Unexpected hypoglycemia
BEFORE TREATMENT WITH GLUCOSE: BMP – lab glucose to confirm Accuchek Plasma insulin Plasma C-peptide Plasma proinsulin
ANY TIME CLOSE TO HYPOGLYCEMIA: Plasma sulfonylurea assay Call chemistry lab medicine resident to confirm samples
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