Updated: 5/20/2017

Growth Hormone Adenoma / Acromegaly

Topic
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Questions
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Evidence
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Snapshot
  • A 52 year-old man complains of increased hat size and headaches when he wakes up in the morning. Physical exam reveals mild diastolic hypertension, prominant jaw with spaces between the teeth, large hands and feet, and generalized muscle weakness.
Introduction
  • Benign pituitary adenoma that releases excess growth hormone
    • GH stimulates release of insulin growth-like factor 1 
  • Gigantism if the condition occurs before the fusion of the epiphysis
  • Acromegaly if it occurs after skeletal epiphyseal closure
Presentation
  • Symptoms
    • generalized enlargement of bone and soft tissue
      • large hands and feet
      • frontal bossing
        • leads to increased hat size
      • space between teeth
        • jaw grows but teeth remain the same size
      • macroglossia
      • carpal tunnel syndrome 
        • size of median nerve increases due to edema
  • Physical exam
    • HTN
      • due to the anti-naturiuretic action of GH
Evaluation
  • Photographic changes
    • for acromegalic features examine an old photograph to reveal changes in facial bones
  • Serology
    • ↑ IGF-1 
      • more sensitive test because the level is more constant than the pulsatile release of GH
    • hyperglycemia
      • due to gluconeogenic action of GH
  • Suppression tests
    • GH release not suppressed by glucose challenge
  • MRI/CT
    • shows enlargement of sella turcica on imaging
  • Cardiomegaly on CXR
    • hypertrophy of left ventricle
Treatment
  • Surgical
    • transphenoidal surgery
  • Medical
    • octreotide (somatostatin analogue)
      • supresses GH release
    • dopamine analog
      • second line for refractory tumors
    • GH receptor antagonists
      • pegvisomant
Prognosis, Prevention, and Complications
  • Cardiomegaly progressing to CHF is the most common cause of death
 

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Questions (4)
Lab Values
Blood, Plasma, Serum Reference Range
ALT 8-20 U/L
Amylase, serum 25-125 U/L
AST 8-20 U/L
Bilirubin, serum (adult) Total // Direct 0.1-1.0 mg/dL // 0.0-0.3 mg/dL
Calcium, serum (Ca2+) 8.4-10.2 mg/dL
Cholesterol, serum Rec: < 200 mg/dL
Cortisol, serum 0800 h: 5-23 μg/dL //1600 h:
3-15 μg/dL
2000 h: ≤ 50% of 0800 h
Creatine kinase, serum Male: 25-90 U/L
Female: 10-70 U/L
Creatinine, serum 0.6-1.2 mg/dL
Electrolytes, serum  
Sodium (Na+) 136-145 mEq/L
Chloride (Cl-) 95-105 mEq/L
Potassium (K+) 3.5-5.0 mEq/L
Bicarbonate (HCO3-) 22-28 mEq/L
Magnesium (Mg2+) 1.5-2.0 mEq/L
Estriol, total, serum (in pregnancy)  
24-28 wks // 32-36 wks 30-170 ng/mL // 60-280 ng/mL
28-32 wk // 36-40 wks 40-220 ng/mL // 80-350 ng/mL
Ferritin, serum Male: 15-200 ng/mL
Female: 12-150 ng/mL
Follicle-stimulating hormone, serum/plasma Male: 4-25 mIU/mL
Female: premenopause: 4-30 mIU/mL
midcycle peak: 10-90 mIU/mL
postmenopause: 40-250
pH 7.35-7.45
PCO2 33-45 mmHg
PO2 75-105 mmHg
Glucose, serum Fasting: 70-110 mg/dL
2-h postprandial:<120 mg/dL
Growth hormone - arginine stimulation Fasting: <5 ng/mL
Provocative stimuli: > 7ng/mL
Immunoglobulins, serum  
IgA 76-390 mg/dL
IgE 0-380 IU/mL
IgG 650-1500 mg/dL
IgM 40-345 mg/dL
Iron 50-170 μg/dL
Lactate dehydrogenase, serum 45-90 U/L
Luteinizing hormone, serum/plasma Male: 6-23 mIU/mL
Female: follicular phase: 5-30 mIU/mL
midcycle: 75-150 mIU/mL
postmenopause 30-200 mIU/mL
Osmolality, serum 275-295 mOsmol/kd H2O
Parathyroid hormone, serume, N-terminal 230-630 pg/mL
Phosphatase (alkaline), serum (p-NPP at 30° C) 20-70 U/L
Phosphorus (inorganic), serum 3.0-4.5 mg/dL
Prolactin, serum (hPRL) < 20 ng/mL
Proteins, serum  
Total (recumbent) 6.0-7.8 g/dL
Albumin 3.5-5.5 g/dL
Globulin 2.3-3.5 g/dL
Thyroid-stimulating hormone, serum or plasma .5-5.0 μU/mL
Thyroidal iodine (123I) uptake 8%-30% of administered dose/24h
Thyroxine (T4), serum 5-12 μg/dL
Triglycerides, serum 35-160 mg/dL
Triiodothyronine (T3), serum (RIA) 115-190 ng/dL
Triiodothyronine (T3) resin uptake 25%-35%
Urea nitrogen, serum 7-18 mg/dL
Uric acid, serum 3.0-8.2 mg/dL
Hematologic Reference Range
Bleeding time 2-7 minutes
Erythrocyte count Male: 4.3-5.9 million/mm3
Female: 3.5-5.5 million mm3
Erythrocyte sedimentation rate (Westergren) Male: 0-15 mm/h
Female: 0-20 mm/h
Hematocrit Male: 41%-53%
Female: 36%-46%
Hemoglobin A1c ≤ 6 %
Hemoglobin, blood Male: 13.5-17.5 g/dL
Female: 12.0-16.0 g/dL
Hemoglobin, plasma 1-4 mg/dL
Leukocyte count and differential  
Leukocyte count 4,500-11,000/mm3
Segmented neutrophils 54%-62%
Bands 3%-5%
Eosinophils 1%-3%
Basophils 0%-0.75%
Lymphocytes 25%-33%
Monocytes 3%-7%
Mean corpuscular hemoglobin 25.4-34.6 pg/cell
Mean corpuscular hemoglobin concentration 31%-36% Hb/cell
Mean corpuscular volume 80-100 μm3
Partial thromboplastin time (activated) 25-40 seconds
Platelet count 150,000-400,000/mm3
Prothrombin time 11-15 seconds
Reticulocyte count 0.5%-1.5% of red cells
Thrombin time < 2 seconds deviation from control
Volume  
Plasma Male: 25-43 mL/kg
Female: 28-45 mL/kg
Red cell Male: 20-36 mL/kg
Female: 19-31 mL/kg
Cerebrospinal Fluid Reference Range
Cell count 0-5/mm3
Chloride 118-132 mEq/L
Gamma globulin 3%-12% total proteins
Glucose 40-70 mg/dL
Pressure 70-180 mm H2O
Proteins, total < 40 mg/dL
Sweat Reference Range
Chloride 0-35 mmol/L
Urine  
Calcium 100-300 mg/24 h
Chloride Varies with intake
Creatinine clearance Male: 97-137 mL/min
Female: 88-128 mL/min
Estriol, total (in pregnancy)  
30 wks 6-18 mg/24 h
35 wks 9-28 mg/24 h
40 wks 13-42 mg/24 h
17-Hydroxycorticosteroids Male: 3.0-10.0 mg/24 h
Female: 2.0-8.0 mg/24 h
17-Ketosteroids, total Male: 8-20 mg/24 h
Female: 6-15 mg/24 h
Osmolality 50-1400 mOsmol/kg H2O
Oxalate 8-40 μg/mL
Potassium Varies with diet
Proteins, total < 150 mg/24 h
Sodium Varies with diet
Uric acid Varies with diet
Body Mass Index (BMI) Adult: 19-25 kg/m2
Calculator

(M1.EC.4720) A 65-year-old woman presents to her primary care doctor with progressively worsening headaches over the last few years. She has recently been diagnosed with diabetes mellitus and started metformin a week ago. She has no other significant past medical history and has never smoked. Her husband also reports that her face has changed over the past few months. An earlier photograph of this patient and her current appearance are shown side by side in Figure A. Which of the following would most likely be the best test for diagnosing this patient? Review Topic

QID: 108512
FIGURES:
1

Facial radiograph

1%

(1/83)

2

Pituitary MRI

29%

(24/83)

3

Serum IGF-1 measurement

59%

(49/83)

4

Serum GH measurement

8%

(7/83)

5

Chest and Abdominal CT

0%

(0/83)

M1

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(M1.EC.75) A 38-year-old man presents to the endocrinologist with complaints of increased shoe size and headaches in the morning. These symptoms have developed gradually over the past year but have become especially concerning because he can no longer wear his normal-sized boots. He denies any other symptoms, including visual changes. He was recently started on lisinopril by his primary care physician for high blood pressure. His vital signs are within normal limits and stable. On exam, the endocrinologist notes the findings shown in Figures A and B. These facial features are especially striking when contrasted with his drivers license from 10 years prior, when his jaw was much less prominent. The endocrinologist sends a screening blood test to work-up the likely diagnosis. Which of the following organs or glands produces the molecule being tested in this screening? Review Topic

QID: 106818
FIGURES:
1

Anterior pituitary gland

50%

(59/118)

2

Liver

45%

(53/118)

3

Posterior pituitary gland

3%

(4/118)

4

Pancreas

0%

(0/118)

5

Kidney

1%

(1/118)

M1

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