SIADH

ü  ADHà 腎的V2à distal tubule and collecting ductàfree water retention and dilutional hyponatremiaà elevated urine osmolality in the setting of a low plasma osmolality

※ Essential diagnostic criteria:

ü  Plasma osmolality <275 mOsm/kg

ü  Urine osmolality >100 mOsm/kg and urine Na >20 to 40mEq/L

ü  Euvolemia

ü  Normal renal, adrenal, and thyroid function tests

ü  No recent use of diuretic agents

※ Euvolemic hypotonic hyponatremia:

ü  The most common cause of euvolemic hypotonic hyponatremia is SIADH.

ü  Characterized by low to normal total body sodium and normal to elevated total body water.

²  Hypothyroidismà dysregulation of ADH release or clearance, effects on vascular tone, cardiac output, and renal blood flow

²  Adrenal insufficiencyà caused by the loss of negative feedback on ADH secretion

²  Primary polydipsia

²  Potomania

²  Thiazide diuretics

²  Reset osmostat syndromeà shift in the set-point for ADH

²  Nephrogenic syndrome of inappropriate antidiuresisà mutations in the renal vasopressin V2 receptor causing increased water resorption，表現同SIADH但ADH測不到

ü  SIADH is usually self-limited, and the primary management strategy is to correct the underlying etiology.

ü  Loop diureticsà增加free water 排出、讓腎對ADH反應下降àenhance the effect of solute loading

ü  Demeclocycline acts on the renal collecting tubules to diminish responsiveness to ADH. The major side effect is nephrotoxicity.

ü  Vasopressin receptor antagonists exert their activity on renal V2 receptors resulting in a selective water diuresis without affecting sodium excretion

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Subclinical hyperthyroidism

原因：同甲亢

ü   Autoimmune thyroid disease

ü   Autonomous thyroid tissue

ü   TSH-mediated hyperthyroidism

ü   Human chorionic gonadotropin-mediated hyperthyroidism

ü   Thyroiditis

ü   Ectopic hyperthyroidism

會影響：

ü   The skeleton (bone resorption) and the cardiovascular system (increased risk of atrial fibrillation, heart failure, pulmonary hypertension, and angina) are the major target tissues adversely affected.

ü   Subclinical hyperthyroidism may also be associated with an increased risk of dementia.

評估：病史、用藥、PE

ü   Patients on suppressive levothyroxine therapyàTSH低是目標

ü   Patients on T4 for the treatment of hypothyroidismà不可以讓TSH太低

ü   女人要問有沒有懷孕，停經後或有骨鬆風險，可做骨密度檢查作為決定要不要治療的參考依據。

ü   沒吃T4的patients，persistently subnormal TSH values，如考慮藥治療，we obtain a radioactive iodine uptake and scan to help determine the etiology. 如有不只一處increased uptake, this could account for the low serum TSH. 如果沒有吸收，the etiology of subclinical hyperthyroidism may be thyroiditis or recent iodine exposure.

ü   Most patients with thyroiditis require no treatment.

ü   Patients at high risk for complications：(>65 years of age, with risk factors for cardiac arrhythmias, and postmenopausal women with or at risk for osteoporosis)
èIf TSH <0.1 mU/L, we treat the underlying cause of subclinical hyperthyroidism.
èIf TSH is 0.1 to 0.5 mU/L, we suggest treatment if there is underlying cardiovascular disease or if the bone density is low.

ü   Patients at low risk for complications：
èIf TSH <0.1 mU/L, we treat the underlying cause if the patient has symptoms suggestive of hyperthyroidism and/or if a thyroid radionuclide scan shows 不只一處吸收。
èf TSH is 0.1 to 0.5 mU/L, 觀察就好

ü   In observed patients, we measure TSH, free T4, and T3 every six months

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adrenal incidentaloma

1. Cushing==>
     check ACTH/Cortisol(08:00 and 23:00)
           urine cortisol
2. Pheochromocytoma==>
     check 24-hour urinary metanephrines and catecholamines
3. Aldosteronomas==>
     check Na/K, Renin activity and aldosterone

Please also check 24-hr urine Na/K/Cr at the same time

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高血脂健保給付

全民健康保險降三酸甘油酯藥物給付規定
CAD or DM: TG≧200 且 TC/HDL-C>5 或 HDL-C<40
No CAD nor DM: 3-6 個月非藥物治療


全民健康保險降膽固醇藥物給付規定
CAD or DM: TC>160 or LSLS>100
危險因子：
1.高血壓
2. 男性≧45 歲，女性≧55 歲或停經者
3. 有早發性冠心病家族史(男性≦55 歲，女性≦65 歲)
4. HDL-C<40mg/dL
5. 吸菸(因吸菸而符合起步治療準則之個案，若未戒菸而要求藥物治療，應以自費治療)。

2 factors: TC>200 or LDL >130
1 factor: TC>240 or LDL > 160
0 factor: LDL > 190

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Charcot’s Neuroarthropathy

Charcot’s neuroarthropathy affects the joints and bones of the feet. The development of this condition include severe peripheral neuropathy and autonomic dysfunction with increased blood flow to the foot; the peripheral circulation is usually intact.

The actual pathogenesis is poorly understood; however, the patient is vulnerable to trauma that may not recall. Repetitive trauma results in increased blood flow through the bone, increased osteoclastic activity, and remodeling of bone. In certain cases, patients walk on a fracture, which leads to continuing destruction of bones and joints in that area. Acute Charcot’s neuropathy may be triggered by any event that leads to localized inflammation. This may trigger a vicious cycle in which there is increasing inflammation, increasing expression of RANKL (a member of the tumor necrosis factor superfamily), and increasing bone breakdown.

Charcot’s neuropathy is sometimes difficult to distinguish from osteomyelitis or an inflammatory arthropathy. A unilateral swollen, hot foot in a patient with neuropathy must be considered to be a Charcot foot.

Charcot’s arthropathy can be diagnosed in most patients by plain radiography and a high index of suspicion. Radiographs may reveal bone and joint destruction, fragmentation, and remodeling. In such cases, the three-phase bisphosphonate bone scan shows increased bone uptake, although the 111In-labeled bone scan will be negative in the absence of infection.

Management of the acute phase involves immobilization. Evidence suggests that treatment with bisphosphonates, which reduce osteoclastic activity, may reduce swelling, discomfort, and bone turnover markers. Although Charcot’s neuroarthropathy is rare, it should be suspected in any patient with unexplained swelling and heat in a neuropathic foot.

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Glucose clamp technique

Glucose clamp technique is used to measure either how well an individual metabolizes glucose or how sensitive an individual is to insulin. Two types of clamps are quite commonly used.

The hyperglycemic clamp, which requires maintaining a high blood sugar level by perfusion or infusion with glucose, is a way to quantify how fast beta-cells respond to glucose.

The hyperinsulinemic clamp, which requires maintaining a high insulin level by perfusion or infusion with insulin, is a way to quantify how sensitive the tissue is to insulin.

Hyperglycemic clamp technique:
Glu raised to 125 mg/dl above basal levels by a continuous infusion of glucose. The glucose infusion rate is an index of insulin secretion and glucose metabolism. The hyperglycemic clamps are often used to assess insulin secretion capacity.

Hyperinsulinemic-euglycemic clamp technique:
The plasma insulin concentration is acutely raised and maintained at 100 μU/ml by a continuous infusion of insulin. The plasma glucose concentration is held constant at basal levels by a variable glucose infusion. When the steady-state is achieved, the glucose infusion rate equals glucose uptake by all the tissues in the body and is therefore a measure of tissue insulin sensitivity. The hyperinsulinemic clamps are often used to measure insulin resistance.

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Struma Ovarii

A teratoma of the ovary contains thyroid tissue that becomes hyperactive. Mild features of thyrotoxicosis result, such as weight loss and tachycardia, but there is no evidence of goiter or eye signs. Serum FT4 and T3 are mildly elevated, serum TSH is suppressed, and RAIU over the neck is low. Total body scan reveals uptake of radioiodine in the pelvis, rather than in the neck. The disease is curable by removal of the teratoma.

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