COMMON INPATIENT ENDOCRINE CONSULTS

William E. Clutter, M.D.

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

Nonthyroidal illness

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

Calcium disorders

Hypercalcemia Hypocalcemia Post-op parathyroidectomy consults

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)

Pituitary disorders

Sella turcica mass Post-op pituitary surgery

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

received

Helpful phone numbers & names

Chemistry lab medicine resident: 424-1153 Nuclear medicine (docs): 362-2802 Barnes Drug Information: 454-8399 Endocrine surgeons:

• Jeffrey Moley

• Michael Brunt

• Bruce Hall

• Will Gillanders