What are the systemic features of cutaneous microsporidiosis?

Systemic Features of Cutaneous Microsporidiosis

Cutaneous microsporidiosis can lead to significant systemic manifestations including hepatitis, peritonitis, keratoconjunctivitis, myositis, cholangitis, sinusitis, and disseminated CNS disease, particularly in immunocompromised patients. 1

Primary Systemic Manifestations

Gastrointestinal Involvement

• Diarrhea and malabsorption (most common systemic manifestation) 2
• Chronic diarrhea leading to malnutrition, failure to thrive, and severe dehydration 1
• Abdominal cramps, fatigue, vomiting, anorexia, and weight loss 1

Hepatobiliary System

• Hepatitis 1, 2
• Cholangitis with inflammation of biliary epithelium 1, 3
• Acalculous cholecystitis 1
• Sclerosing cholangitis with fever, right upper abdominal pain, and elevated alkaline phosphatase 1, 3

Ocular Manifestations

• Keratoconjunctivitis 1, 2
• Can be the presenting symptom in some patients 4

Respiratory System

• Pulmonary infection (rare but reported) 1
• Sinusitis 5, 2
• Tracheobronchitis 2

Musculoskeletal System

• Myositis 1, 2
• Osteomyelitis 2

Neurological Involvement

• Disseminated CNS disease (rare but serious) 1, 6
• Encephalitis with seizures 2, 6

Urinary System

• Interstitial nephritis 2

Clinical Patterns Based on Immune Status

Immunocompromised Patients

• More likely to develop disseminated disease 1
• HIV-infected patients with CD4 counts below 100 cells/mm³ are at highest risk 3
• Patients on immunosuppressive medications (e.g., mycophenolate mofetil) may develop recurrent subcutaneous nodules 5
• Transplant recipients and patients receiving chemotherapy, corticosteroids, or TNF antagonists are at increased risk 1

Immunocompetent Patients

• Usually have more localized disease
• Less likely to develop systemic manifestations

Diagnostic Considerations for Systemic Disease

• Stool examination for gastrointestinal involvement (at least 3 samples) 1
• Urine sediment examination by light microscopy can identify microsporidia spores in disseminated disease 1
• Endoscopy with biopsy for chronic diarrhea 1
• Tissue biopsy from affected organs may be necessary 5
• Special stains (modified trichrome stain, chemofluorescent agents like Calcofluor white) 1
• Transmission electron microscopy for definitive species identification 4

Treatment Approach for Systemic Microsporidiosis

• Immune reconstitution with HAART is the cornerstone of treatment in HIV-infected patients 1
• Albendazole is effective for Encephalitozoon intestinalis and other species causing disseminated disease 2, 6
• Fumagillin has shown efficacy in some cases 7, 6
• Supportive care with hydration, correction of electrolyte abnormalities, and nutritional supplementation 1

Clinical Pitfalls and Caveats

• Microsporidiosis can mimic other opportunistic infections, leading to diagnostic delays
• Clinical history or physical examination alone cannot differentiate microsporidial infection from those caused by other pathogens 1
• Intermittent shedding of organisms means multiple samples may be needed for diagnosis 1
• CNS microsporidiosis is rare but has poor outcomes if not identified early 6
• Consider microsporidiosis in any immunocompromised patient with unexplained chronic diarrhea, especially with concurrent cutaneous lesions 5

Understanding these systemic manifestations is crucial for early recognition and appropriate management of cutaneous microsporidiosis, particularly in immunocompromised patients where the disease can become life-threatening.