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PubMed This is a summary of 20 peer-reviewed journal articles Updated
Hematology

Monitoring and Living with PNH

At a Glance

Long-term management of Paroxysmal Nocturnal Hemoglobinuria (PNH) requires regular lab testing, especially LDH and flow cytometry, to monitor disease activity. Patients on complement inhibitors must carry a safety card and seek immediate emergency care if signs of meningococcal infection appear.

Living with Paroxysmal Nocturnal Hemoglobinuria (PNH) is a marathon, not a sprint. Once you and your doctor have settled on a treatment plan, the focus shifts to long-term monitoring and maintaining your quality of life. Because PNH is a dynamic disease, your medical team will use specific “mile markers” to ensure your treatment remains effective and you stay safe.

The Tools of Monitoring

Your doctor will use several regular laboratory tests to keep an eye on your PNH activity:

  • LDH (Lactate Dehydrogenase): This is the most important marker for PNH. LDH is an enzyme found inside red blood cells; when those cells burst (hemolysis), LDH spills into your blood [1][2]. High LDH levels usually mean your PNH is active, while stable, low levels suggest your treatment is working well [3][1].
  • Reticulocyte Count: This measures the number of young, newly made red blood cells in your blood. It tells your doctor how hard your bone marrow is working to replace the cells being destroyed.
  • Flow Cytometry: Every 6 to 12 months, your doctor will likely repeat this test to check your clone size (the percentage of PNH cells in your blood) [4][1]. This helps ensure the PNH isn’t growing or evolving into another bone marrow condition [1][5].
  • CBC (Complete Blood Count): This tracks your hemoglobin, white blood cells, and platelets to ensure your bone marrow is healthy and you aren’t becoming more anemic [1][5].

Nutritional Support and Daily Management

Because your bone marrow is constantly working overtime to replace destroyed red blood cells, it needs the right building blocks. Your doctor will likely monitor your iron levels (due to iron lost in the urine) and may prescribe folic acid or iron supplements to support red blood cell production [6]. Staying well-hydrated is also crucial to help your kidneys flush out free hemoglobin.

Understanding “Breakthrough Hemolysis”

Even if your PNH is well-controlled on medication, you may occasionally experience a sudden flare of symptoms, such as dark urine, abdominal pain, or extreme fatigue. This is called breakthrough hemolysis (BTH) [7][8].

BTH usually happens for one of two reasons:

  1. Triggers: A severe infection (like the flu), major surgery, or even extreme physical stress can cause your immune system to “overpower” your medication, leading to a temporary surge in cell destruction [9][8].
  2. Timing: If a dose of your medication is delayed or missed, the levels in your blood may drop too low to keep the complement system quiet [7].

Your Immediate Action Plan: If you notice a sudden flare-up, such as dark urine on a weekend, do not wait until Monday. Page your on-call hematologist immediately for instructions, as you may need a “rescue” dose of your medication [10][11]. If you also have a fever, stiff neck, or severe pain, go straight to the nearest emergency room.

Safety First: The Patient Safety Card

Because complement inhibitors (like eculizumab or ravulizumab) turn off a key part of your immune system, you are at a much higher risk for a rare but life-threatening infection called meningococcal disease [12][13].

You must carry your Patient Safety Card with you at all times [14][15]. This card alerts emergency medical staff that you are on a complement inhibitor. If you ever show signs of infection, you must be treated with antibiotics immediately, even before test results come back [14][16].

Seek emergency care immediately if you experience:

  • A sudden high fever [15][17].
  • A severe, “worst-ever” headache or a stiff neck [15][14].
  • A new rash that looks like tiny red or purple pinpoints [15][18].
  • Confusion, light sensitivity, or severe abdominal pain [14][17].

The Psychological Toll

Living with a rare disease and undergoing regular monitoring can lead to “clone anxiety”—the stress of waiting for lab results or worrying about the next flare-up. It is important to remember that while the fatigue of PNH can be physical, the burden of a chronic diagnosis is also emotional. Lean on patient support groups and your care team to help manage the mental aspects of living with PNH [19][20].

Common questions in this guide

What lab tests are used to monitor PNH?
Your doctor will regularly check your LDH levels to monitor red blood cell destruction. They will also use a complete blood count (CBC), reticulocyte count, and flow cytometry to check your overall bone marrow health and PNH clone size.
What is breakthrough hemolysis in PNH?
Breakthrough hemolysis is a sudden flare-up of red blood cell destruction that happens even when you are on treatment. It can cause symptoms like dark urine, severe fatigue, or abdominal pain and is often triggered by infections, physical stress, or delayed medication.
Why do I need to carry a Patient Safety Card for PNH?
Medications used to treat PNH, such as complement inhibitors, suppress a specific part of your immune system and significantly increase your risk for a dangerous infection called meningococcal disease. The safety card alerts emergency medical staff so you can receive immediate antibiotics if you show signs of infection.
What are the signs of a meningococcal infection while on PNH treatment?
Signs of a life-threatening meningococcal infection include a sudden high fever, a stiff neck, a severe headache, confusion, light sensitivity, severe abdominal pain, or a rash of tiny red or purple pinpoints. If you experience any of these symptoms while on a complement inhibitor, seek emergency medical care immediately.

Questions to Ask Your Doctor

Curated prompts to bring to your next appointment.

  1. 1.What is my 'baseline' LDH level, and at what point should I call you if it starts to rise?
  2. 2.How often will we repeat my flow cytometry to check if my PNH clone size is changing?
  3. 3.If I get a severe infection like the flu or COVID-19, what is our plan for managing a possible 'breakthrough' of my PNH symptoms?
  4. 4.Are there specific doctors or emergency rooms I should go to who are familiar with PNH and complement inhibitors?
  5. 5.Can you review the symptoms of meningitis with me again, including the ones that aren't 'classic' like stomach pain or a rash?

Questions For You

Tap a prompt to share your answer — we'll use it plus this page's context to start a tailored conversation.

References

References (20)
  1. 1

    Abdominal pain in combination with an unexplained hemolytic anemia are crucial signs to test for paroxysmal nocturnal hemoglobinuria: A case report.

    Elias NS, Riedl J, Stouten K, et al.

    Clinical case reports 2019; (7(1)):175-179 doi:10.1002/ccr3.1771.

    PMID: 30656036
  2. 2

    Hematopoietic stem cell transplantation for patients with paroxysmal nocturnal hemoglobinuria previously treated with eculizumab: a retrospective study of 21 patients from SFGM-TC centers.

    Vallet N, de Fontbrune FS, Loschi M, et al.

    Haematologica 2018; (103(3)):e103-e105 doi:10.3324/haematol.2017.182360.

    PMID: 29269526
  3. 3

    Risk factors for thromboembolic events in patients with paroxysmal nocturnal hemoglobinuria (PNH): a nested case-control study in the International PNH Registry.

    Höchsmann B, Peffault de Latour R, Hill A, et al.

    Annals of hematology 2023; (102(11)):2979-2988 doi:10.1007/s00277-023-05402-3.

    PMID: 37668788
  4. 4

    CD71 improves delineation of PNH type III, PNH type II, and normal immature RBCS in patients with paroxysmal nocturnal hemoglobinuria.

    Sutherland DR, Richards SJ, Ortiz F, et al.

    Cytometry. Part B, Clinical cytometry 2020; (98(2)):179-192 doi:10.1002/cyto.b.21853.

    PMID: 31705743
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    Consensus statement for diagnosis and treatment of paroxysmal nocturnal haemoglobinuria.

    Cançado RD, Araújo ADS, Sandes AF, et al.

    Hematology, transfusion and cell therapy 2021; (43(3)):341-348 doi:10.1016/j.htct.2020.06.006.

    PMID: 32713742
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    Literature Review of Fatigue Scales and Association with Clinically Meaningful Improvements in Outcomes Among Patients With and Without Paroxysmal Nocturnal Hemoglobinuria.

    Krishnan S, Sarda S, Kunzweiler C, et al.

    Advances in therapy 2022; (39(5)):1959-1975 doi:10.1007/s12325-022-02111-7.

    PMID: 35316499
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    Eculizumab Dosing Intervals Longer than 17 Days May Be Associated with Greater Risk of Breakthrough Hemolysis in Patients with Paroxysmal Nocturnal Hemoglobinuria.

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    Biological & pharmaceutical bulletin 2016; (39(2)):285-8 doi:10.1248/bpb.b15-00703.

    PMID: 26830487
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    PMID: 28232621
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    Different Levels of Incomplete Terminal Pathway Inhibition by Eculizumab and the Clinical Response of PNH Patients.

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    Frontiers in immunology 2019; (10()):1639 doi:10.3389/fimmu.2019.01639.

    PMID: 31379839
  10. 10

    Complement Inhibition in Paroxysmal Nocturnal Hemoglobinuria (PNH): A Systematic Review and Expert Opinion from Central Europe on Special Patient Populations.

    Bodó I, Amine I, Boban A, et al.

    Advances in therapy 2023; (40(6)):2752-2772 doi:10.1007/s12325-023-02510-4.

    PMID: 37072660
  11. 11

    Comparative effectiveness of pegcetacoplan versus ravulizumab in patients with paroxysmal nocturnal hemoglobinuria previously treated with eculizumab: a matching-adjusted indirect comparison.

    Bhak RH, Mody-Patel N, Baver SB, et al.

    Current medical research and opinion 2021; (37(11)):1913-1923 doi:10.1080/03007995.2021.1971182.

    PMID: 34445916
  12. 12

    Meningococcal Disease in Persons With HIV Reported Through Active Surveillance in the United States, 2009-2019.

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    Open forum infectious diseases 2024; (11(1)):ofad696 doi:10.1093/ofid/ofad696.

    PMID: 38288348
  13. 13

    Reply letter to "Fatal meningococcemia due to Neisseria meningitidis serogroup Y in a vaccinated child receiving eculizumab".

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    PMID: 29923779
  14. 14

    High Risk for Invasive Meningococcal Disease Among Patients Receiving Eculizumab (Soliris) Despite Receipt of Meningococcal Vaccine.

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    Neisseria meningitidis Induced Fatal Waterhouse-Friderichsen Syndrome in a Patient Presenting With Disseminated Intravascular Coagulation and Multiple Organ Failure.

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    A Cluster of Meningococcal Serogroup W135 Infections: A Case Series.

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    Fatigue, symptom burden, and health-related quality of life in patients with myelodysplastic syndrome, aplastic anemia, and paroxysmal nocturnal hemoglobinuria.

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  20. 20

    A novel patient-reported outcome instrument assessing the symptoms of paroxysmal nocturnal hemoglobinuria, the PNH-SQ.

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This page provides educational information on monitoring and living with Paroxysmal Nocturnal Hemoglobinuria. It does not replace professional medical advice or emergency guidance from your hematologist.

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