John Murtagh，楊 輝

譯者按：在全科醫(yī)學(xué)服務(wù)中，我們經(jīng)常會(huì)遇到“糊涂”的老年人，甚至有些老年人會(huì)出現(xiàn)精神癥狀。其中一個(gè)要考慮到的原因是老年人中非常常見的低鈉血癥。低鈉血癥的主要原因可能是利尿劑使用過度，或皮質(zhì)激素缺乏，或功能衰竭。因此，全科醫(yī)生首先要采集病人的用藥史，并通過實(shí)驗(yàn)室檢查確定低鈉血癥，同時(shí)要進(jìn)行必要的鑒別診斷。

1 病史

一位82歲的老年男性病人來診所看病，病人是由常年照顧他的女兒帶來的。老人就診的原因是48 h以來萎靡不振、思維混亂、惡心、呆滯。18個(gè)月前，老人患卒中，不過程度屬于輕度，得到穩(wěn)定的恢復(fù)，直到3 d前還感覺不錯(cuò)。他沒有出現(xiàn)跌倒和失禁問題。

2 用藥情況

老人目前服用的藥物包括降低膽固醇的辛伐他汀(simvastatin)20 mg，1次/d；利尿/降壓藥吲噠帕胺(indapamide)2.5 mg，1次/d；鎮(zhèn)靜藥替馬西泮(temazepam)10 mg，夜間服用。

3 體檢

體檢發(fā)現(xiàn)老人一般軀體狀況良好，不過經(jīng)常對(duì)時(shí)間、人物和地點(diǎn)出現(xiàn)定向障礙。他的表現(xiàn)提示可能有譫妄的情況，因此對(duì)他進(jìn)行簡易精神狀態(tài)檢查。他的生命體征為：體溫37 ℃；脈搏72次/min，規(guī)律；血壓140/80 mm Hg(1 mm Hg=0.133 kPa)；呼吸14次/min；血氧飽和度97%。其他體檢包括心血管檢查、神經(jīng)系統(tǒng)檢查、呼吸系統(tǒng)檢查，結(jié)果都正常。血糖儀讀數(shù)為6.2 mmol/L。

4 提問

4.1 提問1：你可以做哪些鑒別診斷？

4.2 提問2：你應(yīng)該安排哪些實(shí)驗(yàn)室檢查？

5 解答

5.1 解答1：鑒別診斷包括藥物不良反應(yīng)，特別是利尿劑造成的電解質(zhì)紊亂、鎮(zhèn)靜劑造成的不良反應(yīng)。并需要考慮到腎衰竭。

5.2 解答2：你應(yīng)該安排如下實(shí)驗(yàn)室檢查：全血常規(guī)檢查；尿液檢查，包括尿常規(guī)和尿培養(yǎng)檢查；血清電解質(zhì)檢查；腎功能檢查。

6 進(jìn)一步的病史

實(shí)驗(yàn)室檢查的結(jié)果如下：全血常規(guī)檢查：正常；尿液檢查：正常；血清電解質(zhì)檢查：血鈉120 mmol/L(參考值范圍為134～146 mmol/L)，血鉀4.0 mmol/L(參考值范圍為3.4～5.3 mmol/L)；腎功能檢查：尿素4.5 mmol/L(參考值范圍為3～8 mmol/L)，肌酐0.07 mmol/L(參考值范圍為0.04～0.12 mmol/L)。

7 進(jìn)一步提問

7.1 提問3：這個(gè)病人低鈉血癥的最可能原因是什么？

7.2 提問4：低鈉血癥的其他原因是什么？

7.3 提問5：你應(yīng)該怎樣管理這個(gè)病人？

8 解答

8.1 解答3：造成這個(gè)病人低鈉血癥(并繼而造成思維混亂)的最可能原因是使用利尿劑吲噠帕胺，這個(gè)藥物屬于噻嗪類利尿劑。其他利尿劑也可能造成同樣的問題，因此密切觀察病人利尿劑的使用情況是非常重要的。

8.2 解答4：其他可能造成低鈉血癥的原因有：(1)抗利尿激素分泌綜合征，如甲狀腺功能減退、癌癥；(2)腎功能衰竭導(dǎo)致鈉潴留，如腎炎；(3)水?dāng)z入過多，如飲水過多或水潴留、充血性心力衰竭；(4)其他藥物，如血管緊張素轉(zhuǎn)化酶抑制劑、抗癲癇藥。

8.3 解答5：對(duì)這位病人，應(yīng)該采取如下管理措施：(1)停止使用利尿劑吲噠帕胺；(2)安排病人入院治療；(3)限制水和液體攝入；(4)通過靜脈點(diǎn)滴給予等滲氯化鈉溶液(如果體液減少)。

譯者注：

1譫妄：急性發(fā)作的癥狀，表現(xiàn)為意識(shí)清醒程度降低，注意力下降，定向力下降，情緒激動(dòng)或呆滯，睡-醒周期紊亂，甚至出現(xiàn)妄想或幻覺。

2定向力：對(duì)周圍環(huán)境(包括時(shí)間、地點(diǎn)、人物)的察覺和識(shí)別能力以及對(duì)自身狀態(tài)(包括姓名、年齡、職業(yè)等)的察覺和識(shí)別能力。

·WorldGeneralPractice/FamilyMedicine·

1 History

A 82 year old man is brought in by his carer daughter because over the past 48 hours he has become lethargic,confused,nauseated and drowsy.He had suffered a stroke 18 months ago but it was not severe and he has been making steady progress and recently felt well up to about 3 days ago.He has not had any falls or incontinence.

2 Medication

His medication is the cholesterol-lowering agent simvastatin 20 mg once daily,the diuretic agent indapamide 2.5 mg daily,the hypnotic temazepam 10 mg at night.

3 Physical examination

On examination he looks well physically but is disorientated in time,person and place.The routine mini-mental state examination had to be modified as his condition suggested delirium.His vital signs were temperature 37 ℃,pulse 72/min regular,BP 140/80 mm Hg(1 mm Hg=0.133 kPa),respiration 14/min,oxygen saturation 97%.The rest of the physical examination including the cardiovascular,neurological and respiratory systems was normal.Blood glucose reading (glucometer) 6.2 mmol/L.

4 Questions

4.1 Question 1：What are your differential diagnosis?

4.2 Question 2：What investigations would you perform initially?

5 Answers

5.1 Answer 1：Differential diagnoses include an adverse drug reaction particularly to the diuretic (including electrolyte disturbance)and the sleeping pill; kidney failure.

5.2 Answer 2：Blood tests to consider are:Full blood examination,urine analysis,serum electrolytes,kidney function tests.

6 Further history

The investigations with normal ranges are as follows:Full blood examination:normal.Urine：normal.Sodium 120 mmol/L(134-146 mmol/L),Potassium 4.0 mmol/L(3.4-5.3 mmol/L).Urea 4.5 mmol/L(3-8 mmol/L),Creatinine 0.07 mmol/L(0.04-0.12 mmol/L).

7 Further questions

7.1 Question 3：What is the most likely cause of low serum sodium ( Hyponatremia) in this patient?

7.2 Question 4：What are other causes of Hyponatremia?

7.3 Question 5：How would you manage this patient?

8 Answers

8.1 Answer 3：The most likely cause of this man′s low serum sodium -causing confusion-is his diuretic treatment with indapamide which is a thiazide type drug.Other diuretics can cause this problem so careful follow up of patients on diuretics is important.

8.2 Answer 4：Other causes of Hyponatremia：(1)Inappropriate anti-diuretic hormone secretion syndrome e.g.hypothyroidism,lung cancer.(2)Kidney failure to conserve salt e.g.nephritis.(3)Water excess e.g.orally or retention e.g.CCF.(4)Other drugs e.g.ACE inhibitors,anti-epileptics.

8.3 Answer 5：The treatment should be：(1)Stop the suspect drug-indapamide.(2)Admit to hospital.(3)Restrict water and fluid intake.(4) Administer isotonic saline via intravenous drip (if volume depletion).