A review of the role of infections in the aetiology of haemolysis in patients with sickle cell diseases: pathogenesis, management, and prevention

Background: Sickle cell disease (SCD) is associated with chronic haemolysis, immuno-suppression and susceptibility to infections, which may trigger infection-associated haemolysis (IAH). SCD patients are vulnerable to anaemic effect of IAH due to vicious interaction between pre-existing 'inherited' chronic haemolysis and 'acquired' IAH. IAH in SCD manifests as febrile haemolytic crisis with clinical and laboratory features of severe anaemia or pancytopenia. Clinico-pathological perspectives of IAH in SCD are fragmented. This review presents a comprehensive but concise overview of pathogenesis, management and prevention of IAH in SCD. Methodology and results: Online literature search using search terms such as 'sickle cell disease, viral, bacterial, parasitic, fungal, infections, hyperhaemolytic crisis, haemophagocytic syndrome, severe anaemia, pancytopenia' in various combinations was done on PubMed/Medline, Google, Google-Scholar and Bing. Overall, 112 relevant publications were retrieved, which included 109 peer reviewed journal articles, 2 World Health Organization (WHO) technical reports, and 1 edited text book. A range of bacterial (Bartonella spp, Mycoplasma spp., Mycobacterium avium complex), viral (Dengue, SARS-CoV-2, Parvovirus-B19, Cytomegalovirus, Epstein-Barr virus), parasitic (Plasmodium spp., Babesia spp.), and fungal (Histoplasma spp.) infections were associated with IAH in SCD. There are two broad types of IAH in patients with SCD; infection associated extra-medullary haemolysis (IAEMH) and infection associated intra-medullary haemolysis (IAIMH). While IAEMH is associated with severe anaemia due to intravascular haemolysis caused by red cell invasion, oxidative injury, auto-antibodies, and/or pathogen-haem interaction, IAIMH is associated with haemophagocytic tri-lineage destruction of haematopoietic precursors in the bone marrow. Conclusion: Various microbial pathogens have been associated with IAH in SCD. SCD patients with fever, severe anaemia or pancytopenia should be investigated for early diagnosis and prompt treatment of IAH, which is a lifethreatening haematological emergency for which transfusion therapy alone may not suffice. Prompt and sustainable termination of IAH may require therapeutic combination of transfusion, anti-microbial chemotherapy, and immune modulation therapy. SCD patients should also receive counselling on hygiene, barrier protection against vectors, routine chemoprophylaxis for locally endemic diseases, and immunization for vaccine-preventable infections as a long-term preventive strategy against IAH.

Infection associated haemophagocytic syndrome in severe dengue infection – a case series in a district hospital

Haemophagocytic lymphohistiocytosis (HLH) is a potentially fatal disorder resulting from uncontrolled hyperinflammatory response. There had been increase in cases of one of the secondary form of HLH, i.e., infectionassociated haemophagocytic syndrome (IAHS) in severe dengue in recent years. However, the condition remains under diagnosed due to lack of awareness compounded by the lack of validated diagnostic criteria. Severe hepatitis with prolonged cytopenias, severe hyperferritinemia, hypofibrinogenemia and persistent fever were evident in all four cases reported. All the subjects survived with supportive care and adjuvant steroid therapy. Prospective controlled studies are needed to develop diagnostic criteria and management protocol for IAHS in severe dengue.

Otitis externa maligna con ectima gangrenoso en un paciente con infección por VIH / Malignant otitis externa with ecthyma gangrenosum in an hiv-positive patient

La otitis externa maligna es considerada una infección invasiva del conducto auditivo externo, infrecuente y sumamente agresiva, que llega, en ocasiones, a comprometer la base del cráneo. Se presenta habitualmente en inmunocomprometidos, incluidos aquellos con infección por VIH. El ectima gangrenoso es una infección cutánea localizada, inusual, causada, en la mayoría de los casos por Pseudomonas aeruginosa, con compromiso multisistémico y evolución tórpida. La asociación entre ambas entidades es aún más rara. A continuación, presentamos el caso de una mujer de 37 años, con el antecedente principal de infección por VIH desde hace 10 años, adherente al tratamiento antirretroviral y, a pesar de mantener una adecuada respuesta inmunológica y virológica, se presenta a la urgencia de nuestro hospital en shock séptico por otitis externa maligna, con ectima gangrenoso y posible síndrome hemofagocítico como complicación, aislándose Pseudomonas aeruginosa como agente causal.

Malignant otitis externa is an aggressive, infrequent and invasive infection of the external auditory canal. In some cases it leads to skull base compromise, particularly in immunocompromised individuals, including HIV-positive patients. Ecthyma gangrenosum is an unusual, localized cutaneous infection, caused mostly by Pseudomonas aeruginosa, with systemic compromise and a torpid evolution. An association between these 2 entities is even more rare. We present the case of a 37-year old woman with a history of 10 years’ HIV infection and good adherence to antiretroviral therapy. Although she had an adequate immunological and virological response, she presented at our emergency department in septic shock due to malignant otitis externa with ecthyma gangrenosum and possible haemophagocytic syndrome as a complication, with Pseudomonas aeruginosa determined to be the causative agent.

Desorden linfoproliferativo T sistémico de la infancia asociado al virus Epstein-Barr: reporte de un caso / Systemic Epstein-Barr virus-positive T celllymphoproliferative disease of childhood: a case report

Resumen: el desorden linfoproliferativo T sistémico de la infancia asociado al virus Epstein-Barres una entidad clínica de descripción reciente, potencialmente mortal en niños y en adultos jóvenes.Se caracteriza por una proliferación clonal de linfocitos T con un fenotipo citotóxico activadoinfectados por el virus. Es más frecuente en países de Asia y México, y se desconoce su incidenciaen el medio. Se reporta un caso de esta enfermedad, con progresión indolente y desenlace fatal.

Abstract: systemic Epstein-Barr virus-positive T cell Iymphoproliferative disease of childhood is arecently described, potentially lethal clinical entity in children and young adults, characterized bya clonal proliferation of EBV-infected T-cells with an activated cytotoxic phenotype. It is typicallyprevalent in Asian countries and Mexico, and its incidence is unknown in our country. This reportdescribes a case of systemic Epstein-Barr virus positive.

Persistently elevated serum transcobalamin II in a patient with reactive haemophagocytic syndrome.

A 24-year-old man was admitted to the hospital with a history of prolonged fever, peripheral blood neutropenia and bone marrow showing benign haemophagocytic histiocytosis. He presented with symptoms and manifestations over a brief duration until death, with the progressive development of multi-organ dysfunction. His serum TCII levels were persistently elevated throughout the disease duration in the hospital. Available evidence indicates that macrophages, mononuclear cells and histiocytes can produce TCII. Serum TCII levels in patients with reactive haemophagocytic syndrome are therefore elevated due to the increased be helpful in making the diagnosis in these patients.