UNASSIGNED: Methemoglobin is an altered state of hemoglobin where iron in hemoglobin is oxidized and incapable of binding oxygen; leading to complications such as cyanosis, dyspnea, headache, and heart failure. Methemoglobinemia can be congenital or acquired. Congenital methemoglobinemia is a rare disease and its worldwide incidence is unclear. We recently encountered the first documented case of congenital methemoglobinemia at our institution, necessitating perioperative care.
UNASSIGNED: In the present case, a 22-year-old man with congenital methemoglobinemia underwent general anesthesia for dental extraction. The surgeon was informed to avoid local anesthetics and oxygenation was performed with FiO2 of 1.0. Arterial blood gas analysis showed a PH of 7.337, PaO2 of 302 mm Hg, PaCO2 of 44 mm Hg, oxyhemoglobin level of 63.4%, and methemoglobin level of 37.8%. The patient had a stable course. No methylene blue therapy was required, although cyanosis was observed during surgery.
UNASSIGNED: In summary, though rare, congenital methemoglobinemia poses fatal risks during surgery. Its management involves preoperative recognition and optimization, oxygenation status, multidisciplinary care, avoiding precipitating or oxidizing agents, discussing treatment options, maintaining cardiopulmonary stability, and ensuring perioperative safety measures with the medical team.

Methemoglobinemia is a rare dyshemoglobin disorder which can either be congenital or acquired. Dyshemoglobin disorders can be asymptomatic or symptomatic. We narrate the case of a 12-year-old girl who presented with a fever, cough, and oxygen saturation of 85%. She was diagnosed with COVID-19, along with a large atrial septal defect and pulmonary arterial hypertension. Arterial blood gas analysis revealed normal partial pressure of oxygen and on 100% exposure to oxygen, blood color turned chocolate brown. After the resolution of COVID-19 in 10 days, the patient was treated with oral ascorbic acid and successful atrial septal defect repair. It is important to suspect dyshemoglobin disorder in a patient who presents with hypoxia/hypoxemia.

Total anomalous pulmonary venous return (TAPVR) represents a group of anomalies consisting of a lack of connection between the pulmonary veins and the left atrium. All oxygenated pulmonary venous return flows directly or indirectly into the right atrium. Survival is only possible with a right-to-left atrial shunt. It remains rare, accounting for less than 1% of all congenital heart diseases. Its association with tetralogy of Fallot is much rarer and has been documented in medical literature as isolated cases. Early prenatal diagnosis, rapid surgical repair, and optimal postoperative resuscitation appear to be the best guarantee of a favorable outcome following total repair of a pulmonary venous connection anomaly. Non-obstructed forms present as high-flow shunts with moderate cyanosis. The symptomatology of blocked forms is dominated by the obstruction to venous return; a clinical picture of respiratory distress with intense cyanosis and severe pulmonary arterial hypertension develops from the first days of life. Echocardiography is fundamental in diagnosing TAPVR. If the results are inconclusive, magnetic resonance imaging and computed tomography are appropriate alternatives for establishing a complete and accurate diagnosis. We report a case of a two-month and 22-day-old infant who is a product of a twin pregnancy, presenting with a non-obstructed TAPVR associated with tetralogy of Fallot, and his twin who died on day 20 of life, likely due to a complex cyanotic congenital heart disease.

Indoxacarb, a large-spectrum non-organophosphorus oxadiazine insecticide, is broadly used in farming whose mechanism of action is the blockage of voltage-gated sodium channels of insects. There is restricted data on human poisoning. We report a case of an 18-year-old male patient without comorbidities presented with unconsciousness and cyanosis after the intentional ingestion of indoxacarb in a suicide attempt. Methemoglobinemia was clinically suspected and was successfully treated after methylene blue injection, associated with supportive and symptomatic management. This case emphasizes the importance of considering methemoglobinemia after indoxacarb ingestion in addition to its early recognition and timely injection of methylene blue which led to complete recovery without sequelae.

Acquired methemoglobinemia (MetHb) is a rare but potentially life-threatening condition that has varied etiology, usually toxin- or drug-induced. We had five cases of acquired methemoglobinemia during six months. Their presentation varied from an asymptomatic state to respiratory distress. The presence of cyanosis and low oxygen saturation (SpO2), despite normal partial pressure of oxygen (PaO2) and chocolate brown-colored blood, were diagnostic clues present in all cases. A high level of methemoglobinemia was detected on arterial blood gas (ABG), confirming the diagnosis. Methylene blue was used as an antidote along with supportive care in symptomatic cases. All these cases of methemoglobinemia recovered completely. A high index of suspicion for methemoglobinemia should be maintained in cases presenting with persistent hypoxia or cyanosis despite normal PaO2.

BACKGROUND: Tracheal agenesis, or tracheal atresia, is a rare congenital anomaly. The presence of a tracheoesophageal fistula (TEF) can help with breathing for newborns with tracheal agenesis. In this article, we presented three unique cases and outcomes of neonates with tracheal agenesis along with a review of the literature.
METHODS: This study consisted of a single center case series followed by a review of literature. Case reports were generated using both written and electronic medical records from a single hospital. We summarized three unique cases and outcomes of neonates with tracheal agenesis and performed a review of the literature.
RESULTS: We identified three cases of tracheal agenesis presented with severe cyanosis without spontaneous crying upon birth. Experienced pediatricians attempted to intubate the babies but were unsuccessful. Endotracheal tubes were subsequently either accidentally or purposely placed into the esophagus, and oxygen saturation levels improved. This suggested tracheal agenesis with TEF. Two cases underwent surgical intervention after resuscitation with esophageal intubation.
CONCLUSIONS: Esophageal intubation may be a life-sustaining ventilation support for patients with tracheal agenesis and TEF at initial resuscitation. Clinicians should suspect tracheal agenesis when a newborn presents with severe cyanosis and voiceless crying upon birth, and esophageal intubation should be immediately attempted.

Sudden unexpected postnatal collapse (SUPC) is a sudden collapse of the clinical conditions of a full-term or near-term newborn, within the first 7 days of life, that requires resuscitation with positive ventilation and who either dies, has hypoxic-ischemic encephalopathy, or requires intensive care. The incidence of SUPC is very low, and most often presents a negative prognosis. The BUB1B gene is a mitotic checkpoint of serine/threonine kinase B that encodes a protein crucial for maintaining the correct number of chromosomes during cell division. Mutations in the BUB1B gene are linked to mosaic variegated aneuploidy syndrome 1 (MVA1), a rare autosomal recessive disorder characterized by diffuse mosaic aneuploidies involving several chromosomes and tissues. This paper discusses a case of a newborn who had a spontaneous delivery. After 2 h and 10 min, the infant showed generalized hypotonia and cyanosis, and his doctors performed orotracheal intubation, cardiac massage, pharmacological hemodynamic therapy, mechanical ventilation, antibiotic therapy, and hypothermic treatment. The newborn was discharged after 5 months with the diagnosis of hypoxic-ischemic encephalopathy. Suspecting an SUPC, a complete genetic analysis was performed demonstrating a compound heterozygous mutations in the BUB1B gene. The newborn died at 6 months of life, 1 month after discharge. A complete autopsy was performed, determining that the cause of death was due to sepsis starting from a brocopneumonic process, with outcomes of hypoxic-ischemic encephalopathy (HIE). In this scenario, it is not possible to demonstrate the causal effect of this mutation, considering that it could play a causal or concausal role in the onset of SUPC. Further research based on multicenter studies, as well as on animal models, could be very useful to clarify the pathological effect of this mutation.

 Cyanosis is a bluish discoloration of the tissues due to increased levels of deoxygenated hemoglobin in capillaries. It is a common finding in newborn infants that can be caused by different diseases, including pulmonary, cardiac, infectious, and hematological disorders. Methemoglobinemia is a rare cause of cyanosis, in which hemoglobin is oxidized, changing its heme iron configuration from the ferrous (Fe2 +) to the ferric (Fe3 +) state, creating methemoglobin (Met-Hb), a form that does not bind oxygen, leading to decreased oxygen delivery to the tissues and cyanosis. We report a rare case of a preterm newborn, who developed cyanosis and worsening hypoxemia on day ten of life, she was found to have elevated Met-Hb percentage in blood gas analysis that required treatment with intravenous methylene blue. Her symptoms resolved after a period of maintenance treatment with oral methylene blue and ascorbic acid, and the etiology of her disease remains unclear.

BACKGROUND: Brain abscesses are rare but potentially fatal condition and can be associated with cyanotic congenital heart disease of which 5-18.7% of these patients that develop cerebral abscess commonly have tetralogy of Fallot (TOF).
METHODS: We report a case of 3-year-old Muganda male that presented with convulsions, cyanosis and difficulty in breathing. The patient had a combination intervention of medical treatment and surgical drainage of the abscess. Post-operative Computerized tomography scan images and pre-operative brain Computerized tomography scans were compared. The multiple rings enhancing lesions were reduced in number and sizes. The largest measured ring was 44 × 22.5×16mm compared to the previous; 42 × 41×36mm. The mass effect had reduced from 16 mm to 7.5 mm. The periventricular hypodensities persisted. Findings showed radiological improvement with residual abscesses, subacute subdural hematoma and pneumocranium. The patient was treated with intravenous ceftriaxone 1 g OD for six weeks and he showed marked improvement and was discharged home after 3 months.
CONCLUSIONS: A comprehensive strategy involving medications, surgical drainage, and early neurosurgical consultation is vital in treating brain abscesses in uncorrected TOF. Early identification of the pathogen, appropriate antibiotic therapy, and vigilant follow-up through clinical assessments and imaging are crucial, potentially spanning a 4-8-week treatment.

BACKGROUND: Cyanotic nephropathy, a rare disease characterized by proteinuria, decreased estimated glomerular filtration rate, thrombocytopenia, polycythemia, and hyperuricemia, may occasionally be secondary to cyanotic congenital heart disease (CHD). There are currently no detailed diagnostic criteria or treatments for cyanotic nephropathy, owing to its extremely low incidence. Eisenmenger syndrome (ES) was initially defined by Paul Wood in pathophysiologic terms as \"pulmonary hypertension (PH) at the systemic level, caused by a high pulmonary vascular resistance, with a reversed or bidirectional shunt at the aorto-pulmonary, ventricular, or atrial level.\" It typically develops in the presence of large, unrepaired atrial or ventricular septal defects, arterial shunts, or complex forms of CHD and is the most severe hemodynamic phenotype of pulmonary arterial hypertension associated with CHD. This study aimed to outline the case of an ES patient who developed cyanotic nephropathy and successfully achieved clinical remission through primary disease treatment and symptomatic management. Overall, this case expands our understanding of cyanotic nephropathy and lays a theoretical reference for the treatment of ES.
METHODS: A 33-year-old Chinese female attended the outpatient department with abnormal urine test results over the past two and a half years. Following a comprehensive medical history collection, she underwent the necessary tests. Cardiac color ultrasound displayed a significant widening of the pulmonary artery and PH (severe), as well as mild tricuspid regurgitation and patent ductus arteriosus. The results of the kidney biopsy, combined with clinical findings, suggested a high risk of polycythemia-related kidney disease. She was eventually diagnosed with cyanotic nephropathy and ES. Her symptoms were relieved following symptomatic treatment, such as the administration of ambrisentan, febuxostat, and home oxygen therapy. Her follow-up visit at 6 months demonstrated improvements in hyperuricemia and a significant increase in physical strength.
CONCLUSIONS: Cyanotic nephropathy is a rare condition in adults. Kidney biopsy remains the gold standard of diagnosis for various nephropathies. Active treatment of CHD and alleviating hypoxia may be pivotal for the treatment of cyanotic nephropathy.