Find Information About:

Drugs & Supplements

Get information and reviews on prescription drugs, over-the-counter medications, vitamins, and supplements. Search by name or medical condition.

Pill Identifier
WebMD

Pill Identifier

Having trouble identifying your pills?

Enter the shape, color, or imprint of your prescription or OTC drug. Our pill identification tool will display pictures that you can compare to your pill.

Get Started
My Medicine
WebMD

My Medicine

Save your medicine, check interactions, sign up for FDA alerts, create family profiles and more.

Get Started

WebMD Health Experts and Community

Talk to health experts and other people like you in WebMD's Communities. It's a safe forum where you can create or participate in support groups and discussions about health topics that interest you.

  • Second Opinion
    WebMD

    Second Opinion

    Read expert perspectives on popular health topics.

  • Community
    WebMD

    Community

    Connect with people like you, and get expert guidance on living a healthy life.

Got a health question? Get answers provided by leading organizations, doctors, and experts.

Get Answers

Sign up to receive WebMD's award-winning content delivered to your inbox.

Sign Up

Font Size
A
A
A

Paroxysmal Nocturnal Hemoglobinuria (PNH)

What Is Paroxysmal Nocturnal Hemoglobinuria?

When you have paroxysmal nocturnal hemoglobinuria (PNH), red blood cells in your body break apart before they should. Your immune system attacks the red blood cells and breaks them down. It happens because the proteins that would normally protect them from this damage are missing.

You can get this rare blood disease at any age. You aren’t born with it. Although it can be life-threatening, treatments can help you feel better and control some of the complications of PNH.

Recommended Related to

Understanding Hemophilia -- Prevention

At this time, there is no simple way to prevent hemophilia in someone who inherits a defective gene and thus produces too little clotting factor. If hemophilia runs in your family, you can be tested to see whether you carry the defective gene and receive counseling about your chance for having children with hemophilia. Gene therapy clinical trials began in early 1999 in an attempt to cure hemophilia, and in vitro fertilization may allow selection and implantation of embryos that lack the hemophilia...

Read the Understanding Hemophilia -- Prevention article > >

PNH affects everyone differently. Some people have only minor problems, but for others, it's much more severe. The biggest concern is blood clots, which can be deadly. About 40% of people with PNH have one at some point.

Causes

PNH comes from your genes, but you don't get it from your parents, and you can't pass it on to your kids.

A change in a gene, called a mutation, causes your body to make abnormal red blood cells. These cells lack proteins that shield them from your immune system. So your body's immune system breaks them down, a process doctors call hemolysis.

Some doctors believe PNH is related to weak bone marrow. People with a certain type of anemia, called aplastic anemia, are more likely to get PNH. The reverse is also true: People with PNH are more likely to get aplastic anemia, though not everyone does. In this condition, your bone marrow stops making new blood cells.

Symptoms

PNH gets its name from one of its more common symptoms. About half of people with PNH pass dark or bright red blood in their urine at night or in the morning. "Paroxysmal" means "sudden," "nocturnal" means "at night," and "hemoglobinuria" means "blood in the urine."

PNH symptoms are caused by:

  • Broken red blood cells
  • Too few red blood cells (which can cause anemia)
  • Blood clots in your veins

You could have many symptoms or just a few. Usually, the more of the faulty blood cells you have in your body, the more the condition will affect you.

1 | 2 | 3 | 4 | 5

Hot Topics

WebMD Video: Now Playing

Click here to wach video: Dirty Truth About Hand Washing

Which sex is the worst about washing up? Why is it so important? We’ve got the dirty truth on how and when to wash your hands.

Click here to watch video: Dirty Truth About Hand Washing

Popular Slideshows & Tools on WebMD

disciplining a boy
Types, symptoms, causes.
fruit drinks
Eat these to think better.
Balding man in mirror
Treatments & solutions.
No gym workout
Moves to help control blood sugar.
Remember your finger
Are you getting more forgetful?
acupuncture needle on shoulder
10 tips to look and feel good.
Close up of eye
12 reasons you're distracted.
birth control pills
Which kind is right for you?
embarrassed woman
Do you feel guilty after eating?
woman biting a big ice cube
Habits that wreck your teeth.
pacemaker next to xray
Treatment options.
Pink badge on woman chest to support breat cancer
Myths and facts.

Pollen counts, treatment tips, and more.

It's nothing to sneeze at.

Loading ...

Sending your email...

This feature is temporarily unavailable. Please try again later.

Thanks!

Now check your email account on your mobile phone to download your new app.

Women's Health Newsletter

Find out what women really need.