Diagnostic Challenges and Management of Paroxysmal Nocturnal Hemoglobinuria: A Case Report from Nepal

Amit Kumar Thakur, Priya Karna

Abstract

This report highlights the case of a 26-year-old male from Nepal diagnosed with Paroxysmal Nocturnal Hemoglobinuria (PNH), a rare hematological condition. PNH is marked by chronic intravascular hemolysis, bone marrow failure, and an increased risk of thrombosis. The patient exhibited symptoms such as weakness, jaundice, recurrent nosebleeds, dark-colored urine, and joint pain during winters. Clinical examination revealed scleral icterus and hepatomegaly. Laboratory investigations showed anemia, leukopenia, thrombocytosis, elevated LDH levels, and a significant PNH clone identified through flow cytometry. Bone marrow analysis confirmed features consistent with PNH. The report highlights the diagnostic challenges posed by the rarity and varied clinical manifestations of PNH and reviews treatment options, including eculizumab and corticosteroids. It underscores the importance of timely and accurate diagnosis for the effective management of this life-threatening condition.

Introduction

Paroxysmal nocturnal hemoglobinuria (PNH) is a rare acquired hematopoietic disorder. Studies indicate that the incidence of clinically significant cases ranges from 1 to 10 per million people. It primarily affects adults, with the peak onset typically occurring in individuals in their thirties.1 Though PNH is caused by mutation of a gene on X chromosome it affects males and females equally.2

Paroxysmal nocturnal hemoglobinuria (PNH) is a clonal hematopoietic stem cell disorder characterized by chronic intravascular hemolysis, bone marrow failure, and thrombosis. It results from an acquired defect in glycosylphosphatidylinositol (GPI)-anchored proteins, specifically CD55 and CD59.3 The acquired mutation occurs in the PIGA gene (phosphatidylinositol glycan anchor biosynthesis, class

A), which is responsible for the synthesis of GPI anchor proteins.4,5 Complement regulatory proteins protect blood cells, including red blood cells (RBCs), white blood cells, and platelets, from complement-mediated damage. CD55 inhibits the activity of C3 convertases, while CD59 prevents the formation of the membrane attack complex (MAC).6 Deficiencies in these proteins result in complement-mediated cell lysis and various clinical manifestations. Flow cytometry using antibodies against CD55 and CD59 is considered the gold standard for diagnosis.7,8,9

Due to its rarity, PNH is often misdiagnosed, leading to significant delays in achieving a definitive diagnosis.10 Eculizumab, a humanized monoclonal antibody targeting complement protein C5, and allogeneic bone marrow transplantation (BMT) are the only widely recognized effective treatments for patients with PNH.11

Case report

A 26-year-old male from Rampur, Nepal, presented to the medicine outpatient department with complaints of generalized weakness, yellowish discoloration of the skin and eyes for the past 5 years, and nosebleeds for the past 10 days. He reported feeling weak and tired, experiencing shortness of breath (SOB) while climbing uphill. The weakness and SOB started insidiously and occurred intermittently, without any identifiable aggravating or relieving factors. He also experienced occasional episodes of dark-colored urine in the morning, but no clay-colored stools. The nosebleeds occurred 2-3 times a day, with about 5ml of blood per episode. There was no bleeding from other orifices. Additionally, the patient reported occasional photophobia and pain in the large joints (knees and hips) during the winter season.

The patient denied any history of chest pain, palpitations, orthopnea, paroxysmal nocturnal dyspnea (PND), decreased urine output, frothy urine, abdominal pain, nausea, or vomiting. He has no past history of hypertension (HTN), diabetes mellitus (DM), or pulmonary tuberculosis (PTB). The patient is a non-smoker and consumes alcohol occasionally.

On examination, the patient was normotensive with a blood pressure of 110/70 mmHg, a pulse rate of 70 bpm, a respiratory rate of 15/min, and was afebrile. His oxygen saturation (SpO2) was 98% on room air. The patient was calm, conscious,and well-oriented to time, place, and person. Physical examination revealed scleral icterus and hepatomegaly.

The patient’s laboratory findings showed a hemoglobin level of 6.7 g/dl, leukocyte count of 3200/mm³, and platelet count of 184,000/mm³. Biochemical results revealed an elevated LDH level of 2447 U/L (normal range 140-280 U/L), and a reticulocyte count of 3.2%. Due to the unavailability of further investigations, he was referred to a tertiary care center for advanced management.

The patient was followed over time, and subsequent reports revealed the following: both the direct and indirect Coombs tests were negative, anti-nuclear antibody and anti-double strand DNA tests were negative, and the D-dimer level was 0.1 ng/mL. A peripheral blood smear showed evidence of reticulocytosis. Flow cytometry analysis identified a PNH clone in granulocytes (92.10%), monocytes (84.80%), and red blood cells (61.70%).

Bone marrow aspiration revealed a mildly hypercellular marrow with erythroid predominance and mild megaloblastosis. Flow cytometry showed the absence of CD55/59, which confirmed the diagnosis of paroxysmal nocturnal hemoglobinuria (PNH). Although the patient was planned to receive eculizumab therapy, due to the family’s poor financial condition, he was started on oral iron, oral folic acid, and steroids. The patient is currently doing well.

Discussion

PNH is a rare and potentially fatal hematological disorder, posing significant diagnostic challenges, especially in resource-limited settings. Given that many cases are likely undiagnosed, the reported incidence is approximately one to ten cases per million people.12 Patients with PNH may present with symptoms of hemolytic anemia and unexplained thrombosis, as seen in classical PNH, or may present with bone marrow disorders such as aplastic anemia. In some cases, however, there may be no symptoms or presentation at all.13

PNH typically presents as acquired intravascular hemolytic anemia, thrombosis in major veins, and pancytopenia, often associated with moderate to severe bone marrow dysfunction. As mentioned earlier, the condition is characterized by a deficiency in CD55 and CD59. However, deficiencies in these proteins can also beseen in conditions like autoimmune thrombocytopenia, hemolytic anemia, and systemic lupus erythematosus, which may produce symptoms similar to PNH.14,15

Due to the rarity of PNH, it is often misdiagnosed as hematuria, iron deficiency, hemolytic anemia, megaloblastic anemia, refractory anemia, or myelodysplastic syndromes.16 As an example, Yin et al. reported a case of PNH that was incorrectly diagnosed and treated as iron deficiency anemia for a period of three years.17 Similarly, Paudyal et al. from Nepal reported a case of PNH that was initially misdiagnosed as megaloblastic anemia.18 Due to the presence of fatigue, there is a risk of misdiagnosis and prolonged treatment as anemia for several years. To improve diagnostic accuracy, flow cytometry was used, as it offers high sensitivity and specificity. The analysis revealed a significant granulocyte clone (greater than 50%), which correlated with the hemolytic presentation seen in the patient.19

Eculizumab, a humanized monoclonal antibody targeting the terminal complement protein C5, has proven to significantly improve the quality of life for individuals with hemolytic PNH. It effectively reduces hemolysis, lowers the risk of thrombosis, and decreases the need for blood transfusions.20 The complement protein C5 is cleaved by C5 convertase into C5a and C5b, leading to the formation of the Membrane Attack Complex (MAC), which plays a vital role in binding to and disrupting bacterial cell walls, thereby killing microorganisms. However, the use of eculizumab increases the risk of infections. A multicenter phase 3 study conducted by Brodsky et al. identified serious adverse events associated with the drug, including pyrexia (fever), headache, abdominal distension, viral infections, anxiety, and renal impairment.20

Some authors have proposed using short courses of corticosteroids as a potential treatment option to manage acute hemolytic exacerbations. However, the role of corticosteroids in alleviating acute exacerbations is still debated, as there is no experimental data to definitively support their effectiveness. Nevertheless, their use may help reduce the severity and duration of crises, potentially avoiding the risks linked to long-term corticosteroid therapy.13, 21

Conclusion

Paroxysmal Nocturnal Hemoglobinuria (PNH) is a rare and complex hematological disorder marked by chronic intravascular hemolysis, bone marrow failure, and thrombosis. It poses diagnostic challenges due to its diverse clinical manifestationsand the risk of misdiagnosis. Treatments such as eculizumab and corticosteroids have demonstrated potential benefits in improving patient outcomes, though their effectiveness and associated risks remain subjects of ongoing discussion. Early and accurate diagnosis is essential for prompt intervention in this uncommon but potentially life-threatening condition.

References

1. Schrezenmeier H, Muus P, Socié G, Szer J, Urbano-Ispizua A, Maciejewski JP, Brodsky RA, Bessler M, Kanakura Y, Rosse W, Khursigara G. Baseline characteristics and disease burden in patients in the International Paroxysmal Nocturnal Hemoglobinuria Registry. haematologica. 2014 May;99(5):922.
2. JV D. Paroxysmal nocturnal haemoglobinuria: clinical manifestations, haematology, and nature of the disease. Ser Haematol.. 1972;5(3):3-23.
3. Ruiz-Delgado GJ, Vázquez-Garza E, Mendez-Ramirez N, Gomez-Almaguer D. Abnormalities in the expression of CD55 and CD59 surface molecules on peripheral blood cells are not specific to paroxysmal nocturnal hemoglobinuria. Hematology. 2009 Feb 1;14(1):33-7.
4. Luzzatto L, Bessler M, Rotoli B. Somatic mutations in paroxysmal nocturnal hemoglobinuria: a blessing in disguise?. Cell. 1997 Jan 10;88(1):1-4.
5. Brodsky RA: Paroxysmal nocturnal hemoglobinuria. Blood. 2014, 124:2804-11.
6. Kinoshita T, Inoue N, Takeda J. Defective glycosyl phosphatidylinositol anchor synthesis and paroxysmal nocturnal hemoglobinuria. Advances in Immunology. 1995 Jan 1;60:57-103.
7. Zacks MA, Garg N. Recent developments in the molecular, biochemical and functional characterization of GPI8 and the GPI-anchoring mechanism. Molecular membrane biology. 2006 Jan 1;23(3):209-25.
8. Rocha JM, Silva ML, Souza ME, Murao M, Araújo SS, Santos SM. Detection of PNH cells by flow cytometry, using multiparameter analysis. Jornal Brasileiro de Patologia e Medicina Laboratorial. 2014 Mar;50:105-14.
9. Rocha JM, Silva ML, Souza ME, Murao M, Araújo SS, Santos SM. Detection of PNH cells by flow cytometry, using multiparameter analysis. Jornal Brasileiro de Patologia e Medicina Laboratorial. 2014 Mar;50:105-14.
10. Angastiniotis M, Ball S, Surrallés J, Castella M, Hill A. Epidemiology of rare anaemias in Europe. Rare Diseases Epidemiology. 2010:375-96.
11. Brodsky RA. Paroxysmal nocturnal hemoglobinuria. Blood, The Journal of the American Society of Hematology. 2014 Oct 30;124(18):2804-11.
12. Angastiniotis M, Ball S, Surrallés J, Castella M, Hill A. Epidemiology of rare anaemias in Europe. Rare Diseases Epidemiology. 2010:375-96.
13. Parker C, Omine M, Richards S, Nishimura JI, Bessler M, Ware R, Hillmen P, Luzzatto L, Young N, Kinoshita T, Rosse W. Diagnosis and management of paroxysmal nocturnal hemoglobinuria. Blood. 2005 Dec 1;106(12):3699-709.
14. Nakamura N, Sugawara T, Shirato KI, Kumasaka R, Nakamura M, Shimada M, Fujita T, Murakami R, Shimaya Y, Osawa H, Yamabe H. Paroxysmal nocturnal hemoglobinuria in systemic lupus erythematosus: a case report. Journal of Medical Case Reports. 2011 Dec;5:1-3.
15. Luzzatto L, Gianfaldoni G. Recent advances in biological and clinical aspects of paroxysmal nocturnal hemoglobinuria. International journal of hematology. 2006 Aug;84:104-12.
16. Kumar R, Dutta S, Kumar H, Lazar AI, Sashindran VK. Diagnostic dilemmas in paroxysmal nocturnal hemoglobinuria. Medical Journal Armed Forces India. 1994 Jan 1;50(1):27-30.
17. Yin XL, Zhou TH, Peng L, Zhang XH, Wang L, Zhou YL, Chen YS, He YY. A case report of concomitant paroxysmal nocturnal hemoglobinuria and heterozygous β-thalassemia. Annals of hematology. 2011 Mar;90:355-6.
18. Paudyal BP, Zimmerman M, Karki A, Neupane H, Kayastha G. Paroxysmal nocturnal hemoglobinuria. Journal of the Nepal Medical Association. 2005 Jan 1;44(157).
19. Pokhrel B, Gautam S, Khanal S, Pokhrel NB, Shrestha A. A Rare and Misdiagnosed Entity Paroxysmal Nocturnal Hemoglobinuria: A Case Report. Cureus. 2021 May 8;13(5).
20. Brodsky RA, Young NS, Antonioli E, Risitano AM, Schrezenmeier H, Schubert J, Gaya A, Coyle L, De Castro C, Fu CL, Maciejewski JP. Multicenter phase 3 study of the complement inhibitor eculizumab for thetreatment of patients with paroxysmal nocturnal hemoglobinuria. Blood, The Journal of the American Society of Hematology. 2008 Feb 15;111(4):1840-7.

21. Issaragrisil S, Piankijagum A, Tang‐naitrisorana Y. Corticosteroids therapy in paroxysmal nocturnal hemoglobinuria. American journal of hematology. 1987 May;25(1):77-83.

Authors

Priya Karna : priya.karna120@gmail.com,

Amit Kumar Thakur : neuroamit012@gmail.com,