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Children with primary or acquired immunodeficiency are at increased
risk for infectious and inflammatory gastrointestinal disorders.1 The
risk and severity of infection depends on the type of immunodeficiency.
Individuals with deficiencies of antibody response are predisposed
to extracellular bacterial infections and intestinal pathogens.
Patients with deficiencies of T cells are predisposed to both intracellular
and extracellular infections. In addition, patients with primary
immunodeficiencies are more prone to develop autoimmune disorders
because of their decreased ability to distinguish self-organisms
from foreign organisms. Autoimmune diseases and celiac disease are
more common in the IgA-deficient patients.
++
Clinical Features
and Differential Diagnosis
++
Gastrointestinal disorders in children with immunodeficiencies
can be associated with infectious (viruses, bacteria, mycobacteria,
fungi, or protozoa) and noninfectious disorders (autoimmune and
alloimmune). Dysmotility, malabsorption, and malnutrition can be associated
with any of these disorders. In addition, medical treatments prescribed
for children with immunodeficiencies may have important gastrointestinal
complications.
++
Gastrointestinal
Infections
++
The pandemic of human immunodeficiency virus (HIV) infection and
acquired immunodeficiency syndrome (AIDS) has heightened our awareness
of opportunistic infections, most of which have been described either
in patients with primary immunodeficiencies or in immunosuppressed
patients with malignancies. These infections are listed in Table 391-1 according to the sites of gastrointestinal
involvement and are discussed in more detail in Section
17. In addition to those listed, immunodeficient patients also
are at increased risk for common bacterial and viral pathogens or
infections with multiple organisms.
++
++
Cytomegalovirus, rotavirus, adenovirus, and herpes simplex virus are
the most common viral agents. Cytomegalovirus is commonly identified
in children with immunodeficiency and can cause inflammation or
ulceration throughout the gastrointestinal (GI) tract, including
the pancreatobiliary system. Symptoms may include diarrhea, dysphagia,
vomiting, abdominal pain, and GI bleeding. Histologic identification
of cytomegalovirus within the intestinal tissue is required to establish
a pathogenic role because cytomegalovirus commonly is excreted in
the urine or stool of asymptomatic individuals. Rotavirus is a cause
of vomiting and diarrhea in immunocompromised children and may disseminate
into the liver parenchyma. In contrast, rotavirus rarely is a pathogen
in normal or immunocompromised adults, most of whom have previously
established immunity. Adenoviruses is reported to cause colitis
in adults with AIDS and fulminant hepatitis in immunocompromised children. Diagnosis
of adenovirus infection depends on histologic identification, which should
be confirmed by culture.2 Herpes simplex virus
usually causes oral and esophageal lesions and produces symptoms
of dysphagia and odynophagia. Other viruses, such as astrovirus, picornavirus,
and calicivirus, have been identified in the stool of HIV-infected
adults with diarrhea, and they also may have a role in pediatric ...