Understanding blastomycosis

Blastomycosis is a fungal infection caused by the thermally dimorphic (forms change with temperature: mold or yeast form) Blastomyces species found in moist soil and decaying wood and leaves. Blastomyces dermatitidis, a fungus, can affect various internal organs in the body, including the skin, bones, lungs, and central nervous system.¹

The fungus affects both adult and paediatric populations, with paediatric cases requiring more attention, especially in early childhood due to their unique physiological and diagnostic treatment responses. Early treatment of blastomycosis is beneficial to reduce complications and improve outcomes in children.²

In this article, we will discuss the symptoms, clinical presentation, diagnostic methods, and treatment options for blastomycosis in paediatric patients, which will provide understanding of the disease.

Clinical presentation of blastomycosis

The onset of illness can occur from two to 15 weeks after inhaling the fungal spores. Symptoms include cough, fever, chills, muscle aches, joint pain, and chest and muscle pain resulting in weight loss, night sweats, and loss of appetite.²

Blastomycosis is not a transmissible disease. However, children with weakened immune systems, organ transplant recipients, and individuals with HIV/AIDS or lung diseases can be at higher risk of developing the disease.³

The three types of blastomycosis

There are three types of blastomycosis: pulmonary (involves lungs), cutaneous (involves skin), and disseminated (other parts of the body). A less rare form of pulmonary blastomycosis can present as acute respiratory distress syndrome (ARDS) because of severe respiratory distress and hypoxia.

Diagnosis typically involves clinical evaluation, imaging, and laboratory tests including microscopy, culture, and serology to confirm the presence of the fungus. Early and accurate diagnosis, followed by appropriate antifungal treatment, is essential to manage the infection and mitigate serious health complications.⁴

The following are symptoms of each of the blastomycosis types.¹

Pulmonary blastomycosis

Pulmonary blastomycosis affects the lungs. ARDS is the rarer form of this disease. The symptoms include:

• Fever
• Cough
• Chest pain
• Shortness of breath
• Fatigue

Cutaneous blastomycosis

Cutaneous blastomycosis appears as painful or painless skin lesions typically spreading from lungs to skin in an infected child, including:

• Warts
• Ulcers
• Abscesses

Disseminated blastomycosis

Disseminated blastomycosis spreads to different body parts. Symptoms include:

• Fever
• Weight loss
• Fatigue
• Swollen lymph nodes
• Neurological and gastrointestinal problems
• Joint pains

Clinical symptoms

Paediatric patients suffer from non-specific symptoms leading to delays in diagnosing the disease. Some overlap with the three forms of blastomycosis symptoms mentioned above. But the most common symptoms include:³

• Respiratory symptoms resembling pneumonia or bronchitis
• Skin lesions resembling bacterial infections
• Osteoarticular (bones and joints) problems causing swelling and joint or bone pain
• Affected central nervous system (severe cases) causes headaches or seizures

Diagnosis

A diverse range of clinical tests are conducted to diagnose blastomycosis in children. Diagnosis primarily involves evaluation, imaging, and laboratory tests:

Clinical evaluation

Clinical evaluation involves taking patient history and physically examining the patient to understand the causes behind the fungal infection and the characteristics of the disease.

Imaging

Imaging involves chest X-rays, CT scanning, or MRI to detect effects on lungs and other organs, respectively.

Laboratory tests 

Laboratory tests using histopathological examinations help understand the characteristics of budding yeast and their effect on the skin, respiratory pathway, or other tissues. 

Antigen tests are employed to detect any complementary antibodies in the sample which bind to the antigens. In addition, polymerase chain reactions (PCR) help in rapid and accurate identification of Blastomyces species.⁵

Treatment

Treatment involves a multifaceted approach focused on antifungal therapy. The treatment depends on the severity and extent of this disease. There are three primary steps to effectively treat blastomycosis.⁶

Mild cases of blastomycosis

Mild cases of blastomycosis require placing the paediatric patient on an antifungal medication (itraconazole). This drug is an oral antifungal medication and the first line of treatment for blastomycosis.⁶

Generally, it treats the patient for a duration of six to 12 months. It functions by inhibiting the synthesis of a compound (ergosterol) that is an essential component of fungal cell membranes.

Severe cases of blastomycosis

Severe cases of blastomycosis involve a more aggressive treatment. The individual is given amphotericin B antifungal medication, which is highly effective in disrupting the fungal cell wall synthesis and hence reducing fungal infection spread in the body.⁶

However, this treatment can disrupt the electrolyte balance in the body and cause potential nephrotoxicity (kidney damage).

After 12 months of the treatment with amphotericin B, individuals with severe blastomycosis are given the itraconazole drug. Itraconazole ensures there is no relapse in the disease and fungal organisms are eliminated. This step is crucial, as itraconazole helps to prevent relapse and ensure that any remaining fungal organisms are eradicated.

Constant follow-up appointments and monitoring are important to ensure continuity of care for paediatric patients and that infection is managed effectively.⁴

Downsides of treatment

Treatment of any disease has its downsides. For blastomycosis, this includes:⁶

• Antifungal treatments can cause liver toxicity, gastrointestinal disturbances, and potential kidney damage, particularly with amphotericin B
• Prolonged treatment durations could lead to medication resistance
• Children may not like the taste or medication form
• Regular monitoring of children and follow-ups may bring stress to parents or carers
• Financial costs of treatment might be a burden to parents
• Affecting children’s academic and physical performance at school

Overall, there are several downsides to treating blastomycosis in children. It is crucial for addressing the infection and preventing its progression. The associated downsides can have profound impacts on the child’s health and daily life. These challenges explain why it is important for the early diagnosis and treatment of blastomycosis to provide the best outcomes for paediatric patients.⁶

FAQs

Can blastomycosis mimic other diseases, and how does this affect diagnosis?

Diseases affecting respiratory pathways, like tuberculosis and lung cancer, can mimic blastomycosis, making it difficult to diagnose. Healthcare professionals use a range of diagnostic techniques to appropriately diagnose the disease.

How does blastomycosis affect a child's development and school performance?

Blastomycosis can affect the quality of life for a child: prolonged illness treatments and frequent medical appointments can lead to absenteeism. Prolonged absenteeism can potentially affect friendships and make it difficult for the child to keep up with academic and physical performance at school.

This will affect a child's self-esteem and confidence. Therefore, it is important to diagnose and treat the condition as early as possible.

How does blastomycosis impact the long-term health of paediatric patients? 

Blastomycosis can cause:

• Chronic respiratory issues
• Growth delays
• Scarring (from cutaneous blastomycosis)
• Psychosocial issues
• Increased risk of secondary infections
• Nutritional deficiencies

What are the environmental factors contributing to being infected with blastomycosis?

A diverse range of environments can provide ideal growth locations for blastomycosis. Some of these include:

• Organic matter: soil with decaying leaves, wood, and other organic material provides ideal conditions for the growth of Blastomyces dermatitidis
• Water bodies: lakes, rivers, and wetlands with moist soil and organic debris
• Forested areas: wooded or forested regions with soils and abundant decomposition
• Construction sites: soil and organic matter during construction can release fungal spores into the environment.
• Agricultural areas: Farms and fields with composting or manure piles
• Animal habitats: wildlife animal activity locations, consisting of burrows or nests
• Indoor spaces (poorly ventilated): indoor spaces with accumulated organic material, old barns, and storage areas
• Climate conditions: warm, humid climates and temperate weather conditions

Summary

Blastomycosis is a fungal infection that affects paediatric and adult populations. The fungus Blastomyces dermatitidis can infect various internal organs in the body, including the skin, bones, lungs, and central nervous system. Though not a transmissible disease, children with weakened immune systems, organ transplant recipients, and individuals with HIV/AIDS or lung diseases are at higher risk of developing it. 

Diagnosing and treating blastomycosis in paediatric patients is challenging due to symptom similarities and the severity of the disease. Understanding the clinical presentation is crucial for the proper management of paediatric patients with this condition. With the correct antifungal treatment regimen, individuals can receive effective care, ensuring continuity and leading to healthier and happier outcomes for children.

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