只做 CT 無法排除 SAH

Is Multidetector CT Sufficient for ED Diagnosis of Subarachnoid Hemorrhage?

Newer multidetector helical CT is not sensitive enough to be used as the sole diagnostic test.
The standard emergency department work-up for subarachnoid hemorrhage (SAH) includes noncontrast head computed tomography (CT) followed by lumbar puncture (LP), if CT is negative. LP is thought to be required after a negative CT result because the reported sensitivity of CT for detecting SAH (90% to 95%) is insufficient for CT to serve as a stand-alone diagnostic modality. Recent reports that newer-generation multidetector helical CT scanners are 98% to 100% sensitive for detecting SAH have prompted some clinicians to advocate for use of these newer CT scanners alone to rule out SAH in ED patients.

Researchers retrospectively assessed the sensitivity of multidetector CT (4-slice, 4-detector) in a review of all patients who had an ED diagnosis of SAH at one academic medical center during a 3-year period. Among the 149 patients, SAH was diagnosed by a positive multidetector CT result alone in 139 patients (sensitivity, 93%) and by a positive LP result after a normal CT result in 10 patients (7%). In the subgroup of 117 patients with a diagnosis of aneurysm or arteriovenous malformation, SAH was diagnosed by a positive CT result alone in 110 (sensitivity, 94%). In the subgroup of 67 patients who had a diagnosis of aneurysm or arteriovenous malformation and who presented with headache and normal mental status, the sensitivity of CT alone was 91%.

Comment: This study shows that CT with newer-generation scanners is inadequate as a stand-alone diagnostic tool to rule out SAH in ED patients. The current practice of performing LP in patients with normal CT scans whose differential diagnosis includes SAH should not change.

— Richard D. Zane, MD, FAAEM
Published in Journal Watch Emergency Medicine June 27, 2008
Citation(s): Byyny RL et al. Sensitivity of noncontrast cranial computed tomography for the emergency department diagnosis of subarachnoid hemorrhage. Ann Emerg Med 2008 Jun; 51:697.

Red Urine

The most common cause of red urine is hematuria. Hematuria can be associated with cystitis or malignancy along with other causes. Other causes of red urine include other sources of heme including myoglobin. Various foods and drugs can also cause red urine. The most common cause of red urine due to food intake is the ingestion of beets. Porphyrins may cause pink or red urine, and the presence of red urine without dysuria, accompanied by abdominal and pelvic pain, raises the question of porphyria.

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New England Journal of Medicine - Vol. 358, No. 26, June 26, 2008

Acute Porphyria

In patients with severe abdominal pain, dark or reddish urine, systemic arterial hypertension, tachycardia, and constipation, the possibility of acute porphyria should be considered. Unfortunately, all of these symptoms occur in other more common conditions, and the diagnosis of porphyria is often overlooked. The diagnostic study of choice is the measurement of 5-aminolevulinic acid (ALA) and porphobilinogen in urine or serum. There are four types of porphyria, and all are due to deficiencies of one or more of the enzymes required for normal heme synthesis. Most types of porphyria are inherited, although the most common type, porphyria cutanea tarda, is usually an acquired disorder associated with liver disease and iron overload.

Q: What is the differential diagnosis of rapidly progressive weakness?
A: The differential diagnosis of rapidly progressive weakness is broad and includes myelopathy, myasthenia gravis, Guillain–Barré syndrome, vasculitic polyneuropathy, neoplastic polyradiculoneuropathy (Eaton–Lambert syndrome), acute porphyria, lead poisoning, arsenic or shellfish ingestion, thallium, hypokalemia, hypomagnesemia, and hypophosphatemia.

Q: Why are the acute porphyrias more common in women than in men?
A: Female sex hormones, particularly progesterone, are porphyrogenic; thus, the acute porphyries are more often clinically manifested in women than in men, and it is rare for symptoms to develop before puberty.

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New England Journal of Medicine - Vol. 358, No. 26, June 26, 2008

Biliary colic 應避免使用 morphine

Q: What is the potential problem with giving intravenous morphine to a patient with biliary colic?

A: Morphine, while potentially providing pain relief, can cause problems in patients with biliary colic of acute cholecystitis as it can induce spasm of the sphincter of Oddi. The nonsteroidal antiinflammatory diclofenac has been shown to reduce pain in patients with biliary colic, but trials are lacking to assess its effects in patients with acute cholecystitis.

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New England Journal of Medicine - Vol. 358, No. 26, June 26, 2008

Acute cholecystitis 為何用抗生素？

Q: When is it necessary to give antibiotics for acute cholecystitis?

A: The rationale for the use of antibiotics and the choice of which antibiotic to use is based on the results of bile cultures from patients with acute cholecystitis. The guidelines of the Infectious Diseases Society of America recommend that antimicrobial therapy be instituted if infection is suspected on the basis of laboratory and clinical findings :

1. more than 12,500 white cells per cubic millimeter
2. body temperature of more than 38.5°C and
3. radiographic findings (e.g., air in the gallbladder or gallbladder wall)

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New England Journal of Medicine - Vol. 358, No. 26, June 26, 2008

Acute Cholecystitis 早點手術為宜

Early laparoscopic cholecystectomy is considered the treatment of choice for most patients with acute cholecystitis. In randomized and prospective trials comparing early laparoscopic cholecystectomy (generally defined as at the time of the initial attack but can be defined as late as 7 days after the onset of symptoms) with a delayed procedure (2 to 3 months after the initial attack), as well as in meta-analyses, early treatment has consistently been associated with shorter overall hospitalization.

In the small minority of patients with severe acute cholecystitis, initial conservative management with antibiotics is recommended, preferably in a high-acuity setting, with the use of percutaneous cholecystostomy as needed; surgery is reserved for patients in whom non-surgical treatment fails.

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New England Journal of Medicine - Vol. 358, No. 26, June 26, 2008

Jaundice in Acute Cholecystitis

Frank jaundice in a patient with signs and symptoms of acute cholecystitis is uncommon. When present, it should raise suspicion of :

1. concomitant choledocholithiasis,
2. Mirizzi's syndrome (obstruction of the bile duct as a result of external compression of a stone in the gallbladder or cystic duct), or
3. another complication, such as gallbladder perforation.

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New England Journal of Medicine - Vol. 358, No. 26, June 26, 2008