Differential Diagnosis for 2 yo with Immunodeficiency, Viral and Fungal Infections, and Hypocalcemia
- Single Most Likely Diagnosis
- Severe Combined Immunodeficiency (SCID): This condition is characterized by a significant impairment in both T and B cell function, leading to severe and recurrent viral and fungal infections, which aligns with the patient's presentation. Hypocalcemia can occur due to vitamin D deficiency or impaired parathyroid function, which might be secondary to the underlying immunodeficiency or its treatment.
- Other Likely Diagnoses
- Chronic Granulomatous Disease (CGD): This condition affects the phagocytic cells' ability to kill certain bacteria and fungi, leading to recurrent infections. Although it primarily involves bacterial and fungal infections, some viral infections can also occur. Hypocalcemia might be seen in the context of vitamin D deficiency or as part of the disease's systemic manifestations.
- DiGeorge Syndrome: Characterized by thymic hypoplasia leading to T cell deficiency, parathyroid gland hypoplasia causing hypocalcemia, and congenital heart defects. Patients are prone to viral and fungal infections due to their immunocompromised state.
- Do Not Miss Diagnoses
- HIV Infection: Although less likely given the age and presentation, HIV can cause significant immunodeficiency, leading to opportunistic viral and fungal infections. Hypocalcemia can be seen in advanced disease due to malabsorption, vitamin D deficiency, or renal impairment.
- Leukocyte Adhesion Deficiency (LAD): This rare condition impairs the ability of leukocytes to migrate to sites of infection, leading to recurrent bacterial and fungal infections. While viral infections are less common, they can occur, and hypocalcemia might be present due to secondary complications.
- Rare Diagnoses
- Hyper-IgE Syndrome (Job Syndrome): Characterized by recurrent cutaneous and pulmonary infections and elevated IgE levels. While primarily associated with bacterial infections, fungal and viral infections can occur. Hypocalcemia is not a primary feature but could be seen in the context of malnutrition or secondary complications.
- Wiskott-Aldrich Syndrome: An X-linked recessive disorder characterized by eczema, thrombocytopenia, and immunodeficiency, leading to recurrent infections. Hypocalcemia might be a secondary finding due to vitamin D deficiency or other systemic effects.