Hayward Zwerling, M.D., FACP

Endocrine Review 1999


Thyroid function tests:
When screening for thyroid dysfunction, the only test that is usually necessary is a TSH. Exceptions to this rule include patients whose thyroid levels are not stable and patients with hypothalamic/pituitary disease. If the TSH is abnormal, an FTI and/or total T3 may be indicated. Thyroid antibodies are rarely needed as their presence or absence usually does not change the treatment plan.



Thyroid nodules:
The work-up for a thyroid nodule should include a TSH and a thyroid fine needle aspiration (FNA) biopsy done by an experienced physician. The FNA is an office procedure which is diagnostic about 85-90%. In most situations, a thyroid ultrasound, thyroid scan or CT scans are unnecessary, as they do not change the need for an FNA. Patients whose FNA returns benign will need life long serial assessment of their nodule as the FNAs have a false negative rate of 3-5%.



Erectile dysfunction
A common mistake is to assume that every man with erectile dysfunction should be treated with Viagra without undertaking a medical evaluation. Before initiating therapy for erectile dysfunction, it is mandatory to establish that the patient’s hypothalamic-pituitary-testicular axis is functioning normally. A defect in any of these endocrine glands may be responsible for erectile dysfunction. Hypothalamus/pituitary lesions, which can lead to erectile dysfunction, include; idiopathic hypogonadotrophic hypogonadism, pituitary tumors, sarcoidosis, craniopharyngiomas, meningiomas, metastatic lesions, hemochromatosis and empty sella syndrome. Testicular defects that can lead to erectile dysfunction include Klinefelter's syndrome, orchitis, aniochoria, hemochromatosis and primary testicular failure. Both morbid obesity and ethanol abuse can also cause low testosterone levels.
Before initiating treatment for erectile dysfunction, patients should have, at least, a free testosterone measured and maybe a FSH and prolactin level. If the testosterone is low, additional diagnostic studies are indicated.



Osteoporosis:
Most patients with osteoporosis have idiopathic osteoporosis. However, the differential diagnosis for osteoporosis also includes: endocrinopathies (estrogen deficiency, androgen deficiency, Cushing’s disease, hyperthyroidism, primary hyperparathyroidism, prolactinomas and diabetes) hematologic malignancies, nutritional deficiencies (calcium deficiency, anorexia nervosa , Vitamin D deficiency,) pharmacologic agents (heparin use, anticonvulsant, steroids,) EtOH abuse, cigarette use, malabsorbtion, chronic metabolic acidosis and immobilization. (…continued)
Before initiating treatment for osteoporosis, the physician should measure the patient’s bone density, calcium, phosphorus, albumin, alk phos, PTH, 25(OH) Vitamin D and TSH. Some patients may benefit from measuring their testosterone level, 24h-urine calcium & Cr excretion, CBC, SIEP, Chem-7 and 1,25(OH)2 Vitamin D levels. If a specific cause of the osteoporosis is found, the treatment should be directed at the underlying pathology rather than treating the patient for idiopathic osteoporosis with either estrogen or Fosamax. All patients with osteoporosis should ensure a diet that contains about 1500 mg of elemental calcium and be supplement with Vitamin D 800 iu.



Diabetic Ketoacidosis:
Patients in diabetic ketoacidosis should be treated with insulin, regardless of their serum glucose. The insulin’s primary function is to correct the acidosis while it also corrects the hyperglycemia. As soon as a diagnosis of DKA is established, these patients should receive Humulin-R 20-30 u IVP. They should simultaneously be started on an insulin drip. The insulin will need to be continued, regardless of their glucose, until the acidosis has been corrected. If necessary, a dextrose solution should be started to maintain the blood sugar while the insulin drip is running. Patients in DKA do not need serial ABGs. The anion gap is the best method to determine when the acidosis has resolved. Due to severe volume depletion, patients in DKA should receive 1-2 L over the first hour and an additional 1-2 L over the next 1-2 hours. The IVF fluid will quickly reduce the hyperglycemia as well as correct the volume depletion. The patient’s volume status, electrolytes, magnesium and phosphorus should be closely followed.



Outpatient Diabetic Management:
Diabetics should have the following assessment:
Their health care provider should evaluate the patient every 2-6 months.
All diabetics should have their sugars control sufficiently to prevent polyuria, polydipisia, fatigue, weight loss, vaginitis and balantitis. The Diabetes Control and Complications Trial has demonstrated that in Type 1 diabetics the risk of development or progression of retinopathy, nephropathy, and neuropathy is reduced 50–75% by intensive treatment regimens. The United Kingdom Prospective Diabetes Study demonstrated that improved blood glucose control in Type 2 diabetics reduces the risk of developing retinopathy and nephropathy and possibly reduces neuropathy by 25%. The reduction in risk of these complications correlated continuously with the reduction in HbA1c. The goal is an HBA1c<7%, preprandial glucose in the 80-120 range and bedtime glucose in the 100-140 range. HBA1c should be monitor every 3-6 months.
As the HBA1c falls, the risk of long-term diabetic complications decreases while the risk of hypoglycemia increases. The risk of hypoglycemia should be appropriate to the clinical situation. Tight control is not appropriate for an 80 year old with ischemic heart disease whereas tight control is clearly appropriate in a reliable 30 year old.
Feet should be inspected at every office visit. Physical assessment of the pedal pulses, carotid pulses, neurologic status and the oropharynx is also indicated.
The primary goal of therapy for adult patients with diabetes is to lower LDL cholesterol to <100 mg/dl.
An assessment for nephropathy should be performed annually. This can be done using an AM spot urine for microalbuminuria or a timed urine collection. Serum creatinine should be monitored periodically.
Electrocardiogram should be done annually.
Diabetics who have had vascular complications, and those at risk for vascular disease, should take aspirin daily.
Annual comprehensive dilated eye examinations by an ophthalmologist or optometrist for who have had diabetes for 3–5 years, all patients diagnosed after age 30 years, and any patient with visual symptoms and/or abnormalities.
Podiatric referrals should be given to those patients with neuropathy or PVD who are unable to care for their toes.
Diabetics should receive an annual influenza vaccine and a pneumococcal vaccine about every 6 years.
Page 2/2 after 1999 ADA Guidelines