Tomographic findings of acute pulmonary toxoplasmosis in immunocompetent patients

Neurotoxoplasmosis in the Immunocompetent: A Rare Occurrence

Cerebral toxoplasmosis is a rare condition that predominantly affects immunocompromised people and is relatively uncommon in immunocompetent individuals. Acute toxoplasmosis primarily presents with focal and diffuse neurological signs and symptoms depending on the site of the lesion, the degree of local damage, and the severity of inflammation. In this report, we present a case of cerebral toxoplasmosis in an immunocompetent adult female who presented with an altered level of consciousness, fever, headache, and shortness of breath. This case highlights the diagnostic challenges that may arise when dealing with patients who have a wide range of clinical manifestations.

Pulmonary and Renal Toxoplasmosis in an Immunocompetent Adult Patient

Toxoplasmosis is caused by the protozoan parasite Toxoplasma gondii (T. gondii), which is one of the most widespread zoonotic pathogens known today. It is a global health hazard as they infect 30-50% of the world's human population. Acute toxoplasmosis is usually asymptomatic and self-limited in immunocompetent people, recovering without treatment and do not require specific therapy. Therefore, rare complications are associated with infection in the individuals with normal immune systems. However, we present a rare case of an immunocompetent man with acute T. gondii infection confirmed by serology, subsequently presented with two life-threatening organ dysfunctions: severe renal and pulmonary involvement, requiring hospitalization and anti-parasitic treatment.

Interstitial pneumonia and diffuse alveolar damage in domestic animals

Classification of pneumonia in animals has been controversial, and the most problematic pattern is interstitial pneumonia. This is true from the gross and histologic perspectives, and also from a mechanistic point of view. Multiple infectious and noninfectious diseases are associated with interstitial pneumonia, all of them converging in the release of inflammatory mediators that generate local damage and attract inflammatory cells that inevitably trigger a second wave of damage. Diffuse alveolar damage is one of the more frequently identified histologic types of interstitial pneumonia and involves injury to alveolar epithelial and/or endothelial cells, with 3 distinct stages. The first is the “exudative” stage, with alveolar edema and hyaline membranes. The second is the “proliferative” stage, with hyperplasia and reactive atypia of type II pneumocytes, infiltration of lymphocytes, plasma cells, and macrophages in the interstitium and early proliferation of fibroblasts. These stages are reversible and often nonfatal. If damage persists, there is a third “fibrosing” stage, characterized by fibrosis of the interstitium due to proliferation of fibroblasts/myofibroblasts, persistence of type II pneumocytes, segments of squamous metaplasia of alveolar epithelium, plus inflammation. Understanding the lesion patterns associated with interstitial pneumonias, their causes, and the underlying mechanisms aid in accurate diagnosis that involves an interdisciplinary collaborative approach involving pathologists, clinicians, and radiologists.

Acute exacerbation of pulmonary toxoplasmosis during corticosteroid therapy for immune thrombocytopenia: A case report and literature review

RATIONALE

Pulmonary toxoplasmosis (PT) is an infectious disease that can be fatal if reactivation occurs in the recipients of hematopoietic stem cell transplantation (HSCT) who were previously infected with Toxoplasma gondii. However, whether the toxoplasmosis reactivation is an actual risk factor for patients receiving immunosuppressive therapies without HSCT remains unclear. Therefore, reactivated PT is not typically considered as a differential diagnosis for pneumonia other than in patients with HSCT or human immunodeficiency virus (HIV).

PATIENT CONCERNS

A 77-year-old man presented with fever and nonproductive cough for several days. He was hospitalized due to atypical pneumonia that worsened immediately despite antibiotic therapy. Before 4 months, he was diagnosed with immune thrombocytopenia (ITP) and received corticosteroid therapy. Trimethoprim-sulfamethoxazole (ST) was administered to prevent pneumocystis pneumonia resulting from corticosteroid therapy.

DIAGNOSIS

The serological and culture test results were negative for all pathogens except T. gondii immunoglobulin G antibody. Polymerase chain reaction, which can detect T. gondii from frozen bronchoalveolar lavage fluid, showed positive results. Therefore, he was diagnosed with PT.

INTERVENTION

ST, clindamycin, and azithromycin were administered. Pyrimethamine and sulfadiazine could not be administered because his general condition significantly worsened at the time of polymerase chain reaction (PCR) examination.

OUTCOMES

The patient died of acute respiratory distress syndrome despite anti-T. gondii treatment. An autopsy revealed a severe organizing pneumonia and a small area of bronchopneumonia.

LESSONS

PT should be considered as a differential diagnosis in patients with pneumonia, particularly in seropositive patients who receive immunosuppressive therapies even for other than HSCT or HIV.

Pulmonary mass-like lesion caused by Toxoplasma gondii in a domestic shorthair cat

A 2-year-old male neutered domestic shorthair cat underwent investigations for acute onset of lethargy, hyporexia, and cough. Computed tomography of the thorax identified a large mass-like lesion in the left cranial lung lobe and bilateral pleural effusion. Thoracotomy and left cranial lung lobectomy were performed. Histopathology of the pulmonary mass was consistent with a localized Toxoplasma gondii pneumonia, confirmed by positive polymerase chain reaction on the affected lung lobe. After adjunctive medical management with a 28-day course of clindamycin (12.5 mg/kg PO q12h), clinical signs resolved and repeat thoracic radiographs documented no abnormalities. The cat remains clinically well 1 year after surgery.

Toxoplasma gondii isolated from a Brazilian patient with rare pulmonary toxoplasmosis has a novel genotype and is closely related to Amazonian isolates

Pulmonary toxoplasmosis is rare in immunocompetent patients. Herein, a Toxoplasma gondii strain isolated in Brazil from an immunocompetent patient who had severe pulmonary involvement was biologically and molecularly characterized for the first time. The TgHumIMTBr1 isolate was bioassayed in mice showing a virulent phenotype. Restriction fragment length polymorphism (RFLP) genotyping using 11 markers [SAG1, SAG2 (5´3´SAG2 and alt. SAG2), SAG3, BTUB, GRA6, c22-8, c29-2, L358, PK1, Apico and CS3] revealed a new non-archetypal genotype assigned as #312. Genotyping using ROP18/ROP5 markers exhibited the virulent combination of alleles 4 and 1. Microsatellite analysis using 15 markers (TUB2, W35, TgM-A, B18, B17, M33, IV.1, X1.1, N60, N82, AA, N61, N83, M48 and M102) revealed an atypical genotype with three unique alleles and a rare combination of alleles 246 (W35) and 203 (TgM-A) that is typical of the Amazon region. Non-archetypal genotypes with unique alleles may function in the occurrence of severe toxoplasmosis in immunocompetent patients in Brazil. Attempts to isolate or molecularly detect T. gondii for further genotyping studies would contribute to the understanding of causes related to the severity of toxoplasmosis in immunocompetent patients.

Pulmonary Toxoplasmosis Diagnosed on Transbronchial Lung Biopsy in a Mechanically Ventilated Patient

Toxoplasma gondii is a protozoan parasite that infects up to a third of the world's population. Infection is mainly acquired by ingestion of food or water that is contaminated with oocysts shed by cats or consuming undercooked meat containing tissue cysts. Primary infection is subclinical in immunocompetent hosts. Invasive toxoplasmosis often manifests as cerebral toxoplasmosis in immunosuppressed patients. In persons living with human immunodeficiency virus (HIV), toxoplasmosis occurs when CD4 counts are very low and is considered an acquired immunodeficiency syndrome (AIDS) defining illness. Pulmonary toxoplasmosis is rarely seen in the highly active antiretroviral therapy era. The diagnosis can be challenging due to the nonspecific nature of clinical and radiographic findings. In this report, we present a case of pulmonary toxoplasmosis in a new onset AIDS patient, which was initially clinically misdiagnosed as Pneumocystis jiroveci pneumonia (PJP). Due to a poor response to treatment for PJP, the patient underwent a transbronchial lung biopsy, which led to the diagnosis of pulmonary toxoplasmosis.

High frequency of infection of lung cancer patients with the parasite Toxoplasma gondii

BACKGROUND

Toxoplasma gondii is an intracellular protozoan parasite that can cause a wide range of clinical conditions, including miscarriage and pneumonia. The global prevalence is 30% in humans, but varies by locality (e.g. in the UK it is typically 10%). The association between lung cancer and T. gondii infection was investigated by direct detection in lung tissue samples.

METHODS

Lung tissue samples were taken from patients undergoing lung resection surgery (n=72) for suspected lung cancer (infection prevalence 100% (95% CI: 93.9-100%)). All 72 participants were confirmed as having lung cancer following subsequent diagnostic tests. In addition, bronchial biopsy samples were collected from non-lung cancer healthy control subjects (n=10). Samples were tested for T. gondii using PCR amplification of T. gondii specific gene markers and T. gondii specific immunohistochemistry.

RESULTS

All 72 lung cancer patients were infected with T. gondii (prevalence 100% (95% CI: 93.9-100%)). Of which, 95.8% (n=69) of patients showed evidence of active parasite stages. Infection prevalence in the controls (10%) was significantly lower (p<0.0001).

CONCLUSIONS

Clinicians treating lung cancer patients should be aware of the potential presence of the parasite, the potential for induction of symptomatic complications and interference with treatment success.

Disseminated toxoplasmosis in a patient with advanced acquired immunodeficiency syndrome

Extracerebral toxoplasmosis, with pulmonary involvement and shock, is a rare form of toxoplasmosis in patients with advanced AIDS. It can mimic pneumocystosis, histoplasmosis, and disseminated tuberculosis, and should be considered in the differential diagnosis of causes of respiratory failure and fulminant disease in this group of individuals, especially in areas where the Toxoplasma gondii infection is highly prevalent and in those without proper use of antimicrobial prophylaxis. We report the case of a 46-year-old male patient who presented to the emergency department with uremia, requiring urgent dialysis. During the laboratorial investigation, the patient had confirmed HIV infection, with a low CD4+ peripheral T-cell count (74 cells/µL). During hospitalization, the patient presented drug-induced hepatitis due to trimethoprim/sulfamethoxazole in a prophylactic dose, requiring interruption of this medication. On the 55th day of hospitalization, the patient developed refractory shock and died. At the autopsy, disseminated toxoplasmosis with encephalitis and severe necrotizing pneumonia were diagnosed, with numerous tachyzoites in the areas of pulmonary necrosis.

A rare case of pulmonary toxoplasmosis in a patient with undifferentiated inflammatory arthritis on chronic methotrexate and corticosteroid therapy

Pulmonary toxoplasmosis is a serious pulmonary condition caused by the protozoan Toxoplasma gondii It typically affects immunocompromised patients presenting acutely with cough, fever, myalgias, arthralgias and lymphadenopathy, and chronically with persistent cough and dyspnoea. Because of its protean features, it can mimic many more common lung conditions in the immunocompromised patient, including atypical pneumonia, Pneumocystis pneumonia and interstitial lung disease. In this article, we present the case of a 55-year-old woman who presented to our hospital with persistent dyspnoea and cough, initially suspected to have an arthritis-related interstitial lung disease. She received a final diagnosis of pulmonary toxoplasmosis after lung biopsy demonstrated Toxoplasma cysts, later confirmed by serology. Treatment with trimethoprim-sulfamethoxazole resulted in significant improvement of her respiratory symptoms after 3 months.