Measles remains a major cause of childhood morbidity worldwide despite the availability of an effective vaccine. Beyond its acute clinical manifestations, measles induces profound but transient immune dysfunction, predisposing affected children to secondary and opportunistic infections. Visceral leishmaniasis (VL) is a systemic protozoal infection caused by Leishmania species and is characterized by prolonged fever, hepatosplenomegaly, pancytopenia, and high mortality if left untreated. The coexistence of severe measles and VL poses a significant diagnostic challenge because of their overlapping clinical and laboratory features. We report the case of a previously healthy three-year-old boy admitted to the pediatric intensive care unit with severe PCR-confirmed measles complicated by acute respiratory failure and hemodynamic instability requiring invasive mechanical ventilation and vasoactive support. Persistent fever, progressive hepatosplenomegaly, and cytopenias despite initial intensive management prompted further investigation, which demonstrated positive rK39 antigen testing and elevated anti-Leishmania antibody titers, establishing the diagnosis of VL. The patient was successfully treated with liposomal amphotericin B, vitamin A supplementation, IV immunoglobulin, and supportive intensive care, resulting in complete clinical recovery without sequelae. To the best of our knowledge, no pediatric case of measles-VL co-infection has been documented previously. This case highlights the diagnostic complexity of persistent systemic inflammation and cytopenias in children with severe measles and illustrates the importance of considering endemic opportunistic infections when the clinical course is atypical or prolonged. The favorable outcome emphasizes the value of early recognition, timely pathogen-directed therapy, and multidisciplinary management, while reinforcing the critical role of measles vaccination in preventing severe disease and its infectious complications.

Hemophagocytic lymphohistiocytosis-macrophage activation syndrome (HLH-MAS) is a life-threatening hyperinflammatory syndrome that can complicate systemic lupus erythematosus (SLE) and present with neurologic manifestations that mimic neuropsychiatric SLE (NPSLE). A 28-year-old woman with a four-year history of SLE initially presented to the emergency department of a community hospital with acute altered mental status and mutism. Laboratory evaluation revealed pancytopenia, markedly elevated ferritin (8,670 ng/mL), hypertriglyceridemia, and hypofibrinogenemia with an erythrocyte sedimentation rate (ESR) that declined from 21 to 6 mm/hr despite active inflammation, a recognized clue distinguishing HLH-MAS from NPSLE. Extensive infectious workup was negative. Although bone marrow biopsy and specialized biomarkers were unavailable at the presenting community hospital, an HScore of 271 (>99% probability of reactive hemophagocytic syndrome) strongly supported the diagnosis of HLH-MAS. High-dose IV methylprednisolone resulted in a progressive decline in ferritin and partial improvement in clinical status, following which the patient was transferred to a tertiary care center for further management. Early recognition of HLH-MAS in SLE patients presenting with acute neurologic symptoms is critical, as misdiagnosis can delay appropriate treatment.

Transcobalamin deficiency is an autosomal recessive disease caused by pathogenic variants in the TCN2 gene. It is a multisystem disorder, with haematological manifestations such as megaloblastic anaemia and pancytopenia. Neurological manifestations include ataxia, hypotonia and neuropathy. Gastrointestinal and immunological clinical presentations include diarrhoea, cytomegalovirus (CMV) colitis, failure to thrive and recurrent infections.We report a female toddler who initially presented at early infancy with severe failure to thrive, diarrhoea, CMV colitis and pancytopenia and was initially diagnosed with childhood myelodysplastic syndrome based on bone marrow examination and a strong family history in her cousins. Whole exome sequencing revealed a homozygous pathogenic variant, c.927_930del (p.(Cys309Trpfs*50)), in the TCN2, consistent with a diagnosis of autosomal recessive transcobalamin deficiency. Treatment with parenteral hydroxocobalamin resulted in dramatic improvement in her symptoms and resolved the myelodysplastic changes.

Gaucher disease is a rare autosomal recessive lysosomal storage disorder that is caused by a deficiency of the enzyme "β-glucocerebrosidase", leading to the accumulation of glucocerebroside within macrophages. It commonly presents with hepatosplenomegaly, cytopenias, and bone marrow infiltration. Gaucher disease is a pan-ethnic lysosomal storage disorder reported worldwide. Although few cases have been described in Pakistan and other South Asian countries, limited awareness and restricted access to diagnostic testing may contribute to underdiagnosis and delayed recognition in this region. We report the case of a 2-year-old girl who presented with fever and cough of 1 week's duration. Her mother reported normal birth and development until 6 months of age, after which she developed progressive weakness and abdominal distension. She had a history of recurrent hospitalizations for anemia, chest infections, and abdominal swelling. Family history revealed consanguinity and early childhood deaths of two siblings and one cousin with similar complaints. The clinical examination revealed pallor, weakness, and marked hepatosplenomegaly. A complete blood count showed features of pancytopenia; therefore, a bone marrow examination was advised, which demonstrated characteristic Gaucher cells, supporting a presumptive diagnosis of Gaucher disease. Symptomatic treatment was initiated, and the patient was referred to Children Hospital, Lahore, Pakistan.

Nitrous oxide (N2O) is a colorless, odorless gas gaining popularity among recreational drug users for its euphoric effects. Whip-it!™ is a low-cost, freely available form of N2O commonly abused in parties and nightclubs. Chronic N2O use can inactivate vitamin B12, causing severe deficiency, anemia, neuropathy, and myelopathy. Here, we report a 19-year-old female with no significant past medical history who was found unresponsive in her apartment. She admitted to daily Whip-it™ use over the preceding three months. In the emergency department, she reported generalized weakness and tingling in all extremities. Workup revealed pancytopenia and profound vitamin B12 deficiency. She was treated with vitamin B12 supplementation and blood transfusions, with significant symptom improvement by discharge. N2O inactivates vitamin B12 through irreversible oxidation of the cobalt atom, causing deficiency and neurologic injury. Unlike other classic causes of vitamin deficiency, such as a vegan diet or pernicious anemia, N2O-induced anemia can occur very rapidly (within days or weeks). Clinicians should consider recreational N2O use in young patients presenting with cytopenias and neurologic symptoms. Given its easy availability and rising misuse, public health education to raise awareness is needed.

Histoplasmosis is a systemic mycosis. In patients infected with HIV, the disseminated form represents one of the most severe presentations of the disease. While the infection primarily manifests in the pulmonary system, it can also present cutaneously or intestinally, posing a significant diagnostic challenge. We report the case of a 28-year-old male patient with a diagnosis of HIV and disseminated histoplasmosis (involving cutaneous, pulmonary, and intestinal systems). He presented with disseminated dermatosis, hepatosplenomegaly, pancytopenia, dysphagia, and subsequent gastrointestinal bleeding; skin and intestinal biopsies confirmed the diagnosis. The patient was treated with amphotericin B (sodium deoxycholate), resulting in a favorable clinical outcome. He was discharged with a subsequent regimen of oral antifungal therapy and antiretrovirals. Disseminated histoplasmosis remains a frequent opportunistic infection in patients living with HIV. Cutaneous manifestations are often nonspecific. In patients with severe immunosuppression, histoplasmosis should always be considered among the differential diagnoses.

Myelodysplastic neoplasms (MDS) are clonal blood disorders that cause ineffective hematopoiesis, low blood counts, and a risk of progression to acute myeloid leukemia. Chemotherapy and radiation usually drive these changes, but a small set of medications, including valproic acid (VPA), can also produce reversible myelodysplastic features. We report a case of VPA-induced myelodysplasia in a middle-aged woman with complex neurologic and psychiatric comorbidities. The patient, with a history of paraplegia secondary to traumatic brain injury and epilepsy, was referred for evaluation of pancytopenia and significant weight loss. She had been treated with VPA for seizure prophylaxis for over a year, with dose escalation to 1000 mg three times daily occurring approximately 3 months prior to presentation. Laboratory evaluation revealed pancytopenia. Peripheral smear showed pseudo-Pelger-Huët cells and thrombocytopenia. Bone marrow biopsy demonstrated mild hypocellularity, erythroid hyperplasia, and dysplasia in the megakaryocytic lineage, but cytogenetic and molecular studies were negative for MDS-associated mutations. We promptly stopped VPA and switched her to lacosamide. Supportive care included a PEG tube for nutrition and one packed red cell transfusion for procedure-related anemia. Her blood counts improved within a week of stopping VPA and normalized completely over the following weeks, with no further cytopenia. This case shows why clinicians should recognize drug-induced myelodysplasia as a reversible mimic of primary MDS. VPA's known hematologic toxicity may stem from its histone deacetylase (HDAC) inhibitor activity, which disrupts normal hematopoiesis. Clinicians should consider VPA-induced myelodysplasia in patients on long-term therapy who present with unexplained cytopenias. Stopping the drug early can produce full hematologic recovery and prevent unnecessary interventions.

Erythropoietic protoporphyria (EPP) is a disease caused by an inborn error of heme biosynthesis. It manifests as painful photosensitivity in childhood. Liver disease occurs due to the deposition of protoporphyrin. Cholestasis due to protoporphyrin leads to a vicious cycle of worsening, which can lead to liver failure. A 29-year-old woman presented with a three-month history of intermittent low-grade fever and a one-month history of jaundice. She had a history of painful blisters over the skin in childhood that started at two years of age and progressed to multiple contractures from healed ulcers by five years of age. She also had splenomegaly on examination. Her blood tests showed pancytopenia, hyperbilirubinemia, and elevated liver enzymes. Tropical fever workup was negative. Autoimmune hepatitis was considered, as antinuclear antibodies (ANA) were positive with elevated immunoglobulin G (IgG). Skin biopsy showed features suggestive of lipoid proteinosis. However, on review with Periodic Acid-Schiff-diastase (PAS-D) staining, a close mimic, EPP was considered a possibility. Liver biopsy showed features of EPP with infiltration with refractile brown pigment showing bright-red birefringence on polarizing microscopy. Next-generation sequencing (NGS) confirmed EPP with a ferrochelatase enzyme coding gene mutation. The patient developed pneumonia during hospitalization and developed acute on chronic liver failure (ACLF) grade 3a, as defined by the European Association for the Study of the Liver (EASL), with ascites and encephalopathy. She was treated with photoprotective measures, ursodeoxycholic acid, antibiotics, and supportive care. The family was counseled regarding options for sequential hepatic and bone marrow transplants. She was managed with the best supportive care.

Hemophagocytic lymphohistiocytosis (HLH) is a rare but life-threatening hyperinflammatory syndrome characterized by dysregulated immune activation and cytokine storm, frequently triggered by infections, autoimmune disorders, and malignancies. Among adults, lymphoma-associated HLH represents one of the most aggressive subtypes and carries significant mortality if not recognized early. We report the case of a 24-year-old male who initially presented with constitutional symptoms, progressive jaundice, and biochemical features suggestive of acute hepatitis. Initial evaluation focused on hepatic and autoimmune etiologies; however, progressive pancytopenia, marked hyperferritinemia (>15,000 ng/mL), hypofibrinogenemia, hypertriglyceridemia, and hepatosplenomegaly raised suspicion for HLH. Further imaging revealed diffuse lymphadenopathy and infiltrative hepatic lesions. Histopathological examination of a supraclavicular lymph node confirmed diffuse large B-cell lymphoma (DLBCL). The patient fulfilled HLH diagnostic criteria with an HScore of 200, indicating high probability of disease. Despite prompt initiation of dexamethasone and immunomodulatory therapy, the patient deteriorated rapidly, necessitating transfer to a tertiary oncology center. This case highlights the diagnostic challenge posed by hepatic-predominant HLH and emphasizes the importance of considering HLH in patients presenting with unexplained hepatitis, cytopenias, and hyperferritinemia.

Osteopetrosis is a rare genetic skeletal disorder caused by defective osteoclast-mediated bone resorption, leading to increased bone density and complications including hypocalcemia, pancytopenia, cranial nerve compression, and, more rarely, hydrocephalus. We report a rare case of intermediate osteopetrosis presenting with neonatal hypocalcemia and progressive macrocephaly. Brain magnetic resonance imaging confirmed obstructive hydrocephalus, which was treated with ventriculoperitoneal shunting. Clinical and radiological findings supported the diagnosis of osteopetrosis, although targeted genetic testing and whole exome sequencing did not identify a causative variant. The patient was treated with calcium gluconate and vitamin D supplementation, followed by hematopoietic stem cell transplantation from an HLA-matched unrelated donor using peripheral blood stem cells. This case highlights the importance of early recognition and timely hematopoietic stem cell transplantation to promote successful engraftment and improve long-term outcomes, even in the absence of molecular confirmation.

ObjectiveHematological involvement is a common manifestation of juvenile-onset systemic lupus erythematosus (jSLE). While nephrological and neurological involvement often guide treatment decisions in the early disease course, hematological findings may also impact morbidity and mortality. The aim of this study is to evaluate the clinical characteristics and treatment approaches of jSLE patients with hematological involvement.MethodThis retrospective, single-center cohort study was conducted on patients diagnosed with jSLE who were followed up at the pediatric rheumatology clinic between January 2015 and May 2025. Patients included in the study had been diagnosed with jSLE according to the 2012 Systemic Lupus International Collaborating Clinics classification criteria.ResultsThe study included 53 SLE patients, 48 of whom (90.6%) were female. The median age at diagnosis was 13 years (IQR: 11-15), and the median follow-up period was 26 months (IQR: 12-48). Hematological involvement was detected in 28 patients (52.8%). Anemia was observed in 18 (64.3%) of 28 patients, followed by lymphopenia in 16 (57.1%), thrombocytopenia in 14 (50.0%), and pancytopenia in 4 (14.3%). The median time to improvement of cytopenia following treatment was 32 days (IQR: 27-61). In 11 patients, treatment was based on isolated hematological findings, whereas in 17 patients with additional major organ involvement, treatment was mainly directed by the major organ manifestations. The frequency of constitutional symptoms, hypocomplementemia, and direct Coombs positivity were found to be significantly higher in patients with hematological involvement (p = 0.003, p = 0.034, p = 0.039, respectively). Intravenous ımmunoglobulin (IVIG) was also found to be administered more frequently in patients with hematological involvement (p = 0.010).ConclusionHematological involvement was detected in approximately half of jSLE patients. Hypocomplementemia and positive Coombs test were more frequently observed in patients with hematological involvement. The use of IVIG was also more common in patients with hematological involvement, and individualized treatment options remain important in the management of the disease.

Vitamin B12 deficiency is a common yet frequently underrecognized nutritional disorder with important public health implications, particularly in low- and middle-income countries where maternal deficiency, vegetarian dietary practices, and food insecurity are prevalent. In children, deficiency may lead to irreversible neurodevelopmental impairment, growth failure, and hematological abnormalities, making early recognition essential. The clinical spectrum ranges from asymptomatic biochemical deficiency and isolated macrocytic anemia to developmental regression, seizures, movement disorders, peripheral neuropathy, and pancytopenia, with neurological manifestations often preceding hematological changes. Diagnosis requires integration of clinical features with laboratory evaluation, including complete blood count, peripheral smear, serum vitamin B12 estimation, and functional biomarkers such as methylmalonic acid and homocysteine, which improve diagnostic accuracy in borderline or atypical cases. Molecular testing has expanded the identification of inherited disorders affecting vitamin B12 absorption and metabolism, enabling timely lifelong management. Prompt replacement therapy is the cornerstone of treatment and should not be delayed when clinical suspicion is high. Oral supplementation is effective for most dietary deficiencies, whereas parenteral therapy is indicated for severe anemia, neurological involvement, malabsorption, or inherited cobalamin disorders. Early treatment results in rapid hematological recovery, but delayed intervention may leave permanent neurological sequelae despite biochemical correction. Beyond individual patient care, strengthening maternal nutrition, targeted screening of high-risk populations, food fortification, and public awareness are critical strategies to reduce the burden of vitamin B12 deficiency and prevent avoidable disability. This review summarizes current evidence on the diagnosis and treatment of pediatric vitamin B12 deficiency and highlights practical approaches for improving clinical outcomes.