The introduction of intravenous immunoglobulin (IVIG) products in the 1980s led to a revolution in the therapy of antibody deficiency. With this innovation it finally became possible to safely give enough immunoglobulin (Ig) to an immunodeficient individual to bring the serum level into the normal range, and its use soon became the standard of care.
However there were some individuals who experienced significant problems with the need for regular access to veins sufficient to permit large volume infusions. Infants, children, the elderly and others with “bad veins” sometimes needed to undergo multiple uncomfortable attempts to find a suitable vein or sometimes to even forego their treatments because of lack of adequate venous access.
Clinical situations are common where reliable venous access is essential for the delivery of needed drugs and blood products on a weekly or less frequent schedule. This challenge has led to the development of semi-permanent infusion ports connected to a large central vein that are then implanted under the skin and accessed by inserting a needle through the skin into the device’s subcutaneous port.
Understandably when IVIG became available, some individuals began to ask about these devices to avoid problems with their monthly Ig infusions, especially if they had limited venous access. Infusion ports implanted under the skin became quite popular and were often recommended by some providers.
With increasing experience, however, most immunologists now do not recommend the use of infusion ports except in extreme situations. The reasons for this reluctance are several. First is the risk of development of a systemic or blood stream infection that implanted catheters carry. These infections can be fatal. Any foreign material in the body causes a local reaction, and this makes it easier for bacteria to take hold in that location. Therefore the port and catheter produce a local environment where any microorganism that enters the body can become more easily established and develop into an active infection. Microorganisms from the skin can gain entry to the port during the needle puncture through the skin to reach the port for infusion and then infect the port and travel down the lumen of the catheter tube and enter a vein causing systemic infection.
Whenever an infection is suspected, the port/catheter should be cultured to determine if it has become colonized with bacteria or fungi. Further, if the patient develops a significant fever, they will be presumed to have an infection and will need to be treated with antibiotics until cultures return and infection is ruled out. If the catheter becomes colonized, prolonged antibiotic treatment may be needed and the catheter/port may need to be removed and replaced to clear the infection. Some types of infections are more likely to result in catheter removal than others and colonization with Candida albicans can be particularly problematic. With some types of infection the port needs removal in over 80% of cases. Routine regular care to maintain the port in good condition is required and may involve irrigating the port with heparin, saline or another solution daily, weekly or monthly depending on the particular port used.
All of these devices also have a certain intrinsic failure rate and will need surgery to remove and replace them. This adds expense and has its own slight risks like any surgical procedure. Another significant issue of concern is that permanent or indwelling catheters have the risk of promoting thrombus or clot formation. This is particularly relevant to the individual receiving IVIG because the product itself has in the past been occasionally associated with thromboembolism. Thromboembolism is one of the listed warnings contained on the IVIG product label and has caused serious blood clots in the lungs and rarely even sudden death. Adding an infusion port makes this complication of IVIG more likely.
The amount of data on the frequency of these complications in patients with primary immunodeficiency diseases (PI) with implanted catheters and ports is very limited. For an example of data available in patients with other medical conditions, a careful study of 132 cancer patients with implanted ports followed for at least one year, found that complications occurred in 26% of the study group. These ranged from early complications associated with surgery to implant the device and included collapsed lungs and excessive bleeding during the surgery. Later complications included system blockage, thrombosis, infection, catheter defects, local leakage and necrosis of the skin at the site of the port.
Given the very serious risk involved with the use of implantable ports, their use must be reserved for situations where the benefits are considerable and not just for convenience.
One alternative that is gaining increasing popularity amongst patients needing Ig replacement treatment is to receive their Ig infusions subcutaneously. In fact, the most recent patient survey conducted by IDF indicates that 45% of respondents are now receiving their infusions at home with self-administered subcutaneous immunoglobulin (SCIG).
SCIG has several features that contribute to this increasing rate of its adoption. In general it has been observed that there are fewer infusion related reactions to SCIG than there are to IVIG infusions. Some people find it more convenient to use since they can easily adjust the timing of infusions to match their own schedule preferences and can often carry on with certain activities that are not possible when tethered to an IV. Serum levels of IgG tend to remain stable during the week between infusions so that recipients do not experience the “week before” symptoms common in some IV recipients. SCIG has also been used successfully to treat all age groups from infants as young as a few months to the elderly.
And finally, SCIG infusion does not require venous access to be able to achieve normal therapeutic levels of IgG. One of the professional groups that focus their activities on PI is currently considering a proposal to recommend against the use of infusion ports for PI except in unusual circumstances because they are no longer needed and, therefore, it is not necessary to accept any risk associated with their use in the patient with antibody deficiency.
In all cases, patients and caregivers should consult their healthcare providers. Each patient’s condition and treatment is unique. This article cannot be applied safely to any individual case and should not be used as a substitute for professional medical advice.
This article was originally published in the IDF ADVOCATE, Winter 2015.