WHATEVER

Acute intermittent porphyria(AIP)

Case

A 27 year old female comes to her physician complaining of severe abdominal pain of 3 days’ duration

She says she has had similar attack in the past, starting in early adolescence.

However, she thought the pain was due to menstruation, and did not seek for medical attention.

Review of system reveals a history of depression and insomnia.

On physical examination, the patient is hyporeflexic in the lower extremities and has generalized weakness,

Which is worse in the lower extremities than in the upper extremities.

Urinalysis reveals the urine color is initially light but darkens on exposure to air and light, and the

porphobilinogen is 110mg/24hr (normal 0-1.5mg/24hr)

Discussion:

紫質症(porphyria)是種相當罕見的疾病，它不是單一病類而是由一群相類似的疾病所組成，疾病發生率根據臨床統計約為30萬分之一，

有遺傳性也有後天性的，而遺傳模式大多是體染色體顯性遺傳。造成疾病的主要原因是紫質（porphyrin）及其衍生物代謝異常所致，

紫質是人類血色素的組成物-血基質(heme)的前驅物，因為合成血基質的酵素活性異常使患者身體內的紫質或其前驅物的過量累積。

目前為止，紫質症已知至少有七種類型，分別是合成血基質途徑中的不同酵素缺陷所造成

   Porphyria (吸血鬼傳說)

   畏光

   皮膚照光會痛(photosensitivity)

   pale, 貧血-heme合成異常

這邊我們只討論最常見的AIP

1.       缺陷酵素: porphobilinogen deaminase

2.       AIP特色是不表現cutaneous disease

3.       Acute attack的症狀:

a.       Abdominal pain

b.      Seizure

c.       Constipation

d.      Vomint / Nausea

e.       Depression

4.       治療首要是避免precipitants of acute attack

a.       Gonadal steroid (月經)

b.      Drugs

c.       Alcohol

d.      Low-calorie diet (節食)

e.       Sunlight

àincrease ALA synthase activity, precipitate attacks

5.       IV dextrose solution can abate acute attack

IV hemin can decrease synthesis of ALA synthase