Breakthrough Infections and Subtle Warning Signs
A breakthrough infection is an infection that occurs despite treatment meant to reduce infection risk, says Gernez.
“The most common misunderstanding when it comes to SCIg therapy is that ‘no infections’ is the only sign of success — or, conversely, that every cold means treatment has failed,” says Gernez.
IgG replacement is especially effective at reducing serious bacterial infections and their long-term consequences, but it can’t prevent every viral illness, fully replace mucosal immunity (immune defenses that protect moist surfaces such as the nose, airways, and digestive tract), or correct all the inflammatory and autoimmune complications of PI, says Gernez.
SCIg is made up almost entirely of IgG, and contains very little immunoglobulin A and immunoglobulin M antibodies that help protect the moist surfaces of the nose, sinuses, and airways, explains Paula Henao, MD, an immunologist at Penn State Health in Hershey, Pennsylvania, and medical director of the Immune Deficiency Foundation.
“That means colds and other respiratory viruses, sinus and ear infections, and bronchitis may still occur even when SCIg is providing good protection against more serious bacterial infections,” she says.
Rather than using a set number of illnesses to judge whether treatment is working, Gernez says it is more useful to look for a change from your usual pattern, including:
[3]
- Infections that are becoming more frequent, prolonged, severe, or difficult to treat
- Repeated bacterial sinus infections, bronchitis, or pneumonia
- Infections requiring repeated courses of antibiotics, intravenous (IV) antibiotics, emergency care, or hospitalization
- A persistent wet or productive cough, chronic nasal or sinus symptoms, declining exercise tolerance, or slow recovery between illnesses
- More missed work, school, exercise, or usual activities because you are sick
- Chronic diarrhea, weight loss, or signs of malabsorption, meaning your body is not properly absorbing nutrients
The site and depth of the infection is important to note, says Dr. Henao. “A deep or systemic infection such as pneumonia or sepsis says far more than a cold or a sinus infection,” she says.
Silent lung damage is the most important thing to be on the lookout for, Henao adds. “Bronchiectasis (chronic damage and widening of the airways) can progress without dramatic infections and even with a reassuring IgG level, so a persistent daily productive cough deserves evaluation even when a person otherwise feels well,” she says.
Not every change is an emergency, but certain symptoms shouldn’t wait for a routine appointment, says Gernez. “Severe breathing difficulty, hypoxia (dangerously low blood oxygen), symptoms of sepsis, or new neurologic symptoms require urgent medical attention,” she says.
