Quinine and Thrombotic Thrombocytopenic Purpura–Hemolytic Uremic Syndrome

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The summary below is from the full report titled "Quinine-Associated Thrombotic Thrombocytopenic Purpura–Hemolytic Uremic Syndrome: Frequency, Clinical Features, and Long-Term Outcomes." It is in the 18 December 2001 issue of Annals of Internal Medicine (volume 135, pages 1047-1051). The authors are K Kojouri, SK Vesely, and JN George.

What is the problem and what is known about it so far?

Thrombotic thrombocytopenic purpura–hemolytic uremic syndrome (TTP–HUS) is an uncommon but serious illness that can cause death. In TTP–HUS, several organs (kidney, brain) get clogged with fragments of red blood cells and platelets. Red cells are broken down faster than they can be replaced (hemolytic anemia). Blood-clotting cells called platelets are reduced (thrombocytopenia) because they get stuck in the areas containing red blood cell fragments. Abnormal clotting or thrombosis results in many parts of the body. Symptoms include confusion, kidney failure, and increased bruising (purpura). Immediate treatment with exchange of plasma (blood fluid without blood cells) prevents death in most patients. This disorder may be caused by an abnormal immune reaction (to a drug or other agent), in which the body produces antibodies that attack many cell types. Quinine, a drug used to treat leg cramps and available in nutrition stores, is the most common cause of drug-related TTP–HUS. The course and outcomes of quinine-associated TTP–HUS are not well known.

Why did the researchers do this particular study?

To describe the clinical features and long-term outcomes of patients with quinine- associated TTP–HUS.

Who was studied?

17 patients with quinine-associated TTP–HUS. All were women. The average age was 64 years.

How was the study done?

The researchers interviewed and examined all patients referred to the Oklahoma Blood Institute for treatment (exchange of large amounts of plasma) for TTP–HUS between 1989 and 2000. Of 225 such patients, 17 had taken quinine regularly, either daily or at least several times weekly, at the time of TTP–HUS onset. The researchers compared features and outcomes of people who had and had not ingested quinine before TTP–HUS onset.

What did the researchers find?

Patients with quinine-associated TTP–HUS usually had abdominal pain, nausea, vomiting, and diarrhea within several hours of ingesting quinine. Most had low urine outputs. One died before receiving treatment. Fourteen of the other 16 patients needed dialysis with a kidney machine. Kidney function usually normalized within a month. One of 2 patients who required permanent dialysis died 5 years after initial complications of kidney failure. Two other patients died during treatment for their initial TTP–HUS episode. Patients who had ingested quinine were more likely to have renal failure than those who had not. However, fewer people with quinine-associated TTP–HUS died than those who had not taken quinine (21% vs. 41%).

What were the limitations of the study?

Only patients referred to a blood institute for plasma exchange were studied. Some patients with less severe TTP–HUS may not have been referred and could have been missed. Also, some patients with severe TTP–HUS that caused immediate death were probably missed.

What are the implications of the study?

Quinine is a common cause of drug-associated TTP–HUS. It can cause death and chronic renal failure. The U.S. Food and Drug Administration has banned over-the-counter marketing of quinine, but the drug is still available in beverages and from nutrition stores, pharmacies, and Internet sites.