**3. Pathophysiology**

Many agents like fungi, bacteria, parasites, viruses and other microorganisms can cause infectious esophagitis. The disease is more prevalent in immunocomprised people, but it can also occur in healthy people, including adults and children [13, 14]. The least common of all causative agents for infectious esophagitis is bacteria, but the most common cause of infectious esophagitis is .

The steps involved in the pathophysiology of infectious esophagitis include:


Whilst *Candida Albicans* is a normal component of oral flora, it can also become a problem if their number increases, for example, with the use of antibiotics or if the patient is immunosuppressed because of treatment with corticosteroids. HSV is the most common cause of viral esophagitis, and it infects the squamous epithelium leading to vesicles and then ulcerations. CMV, Epstein–Barr (EBV) and varicellazoster (VZV) are other viral causes of viral esophagitis.

Individuals may become susceptible to acquiring opportunistic infections like neutropenia, impaired chemotaxis and phagocytosis, impaired T-cell lymphocyte function and alteration in humoral immunity due to wide range of abnormalities in the host defense.

People suffering from various systemic diseases such as adrenal dysfunction, alcoholism, diabetes etc., and older citizens can be prone to catching infectious esophagitis due to altered immune function steroids, radiation, cytoxic agents and immune modulators can also lead to the impaired host immune function.

The mucosal protective barriers and antibiotics that suppress the normal bacterial flora disruption may contribute to the invasive ability of commensal organisms [14]. Categories of infectious are as follows [11–14]:

i.Fungal esophagitis, for example, Candida Esophagitis

ii.Viral esophagitis, for example, HPV esophagitis and CMV esophagitis etc.

iii.Bacterial esophagitis, for example, tuberculosis, actinomycosis etc.

iv.Tuberculous esophagitis as stated in point (iii) above

v.Other infections that can cause esophagitis

Fungal overgrowth in the esophagus, or impaired cell-mediated immunity or both can result in the development of *Candida* esophagitis.

The setting of esophageal stasis leads to cause of fungal overgrowth resulting from:

a.abnormal esophageal motility like achalasia

b.scleroderma or mechanical causes such as strictures.

Dysfunctional cell-mediated immunity can be caused by:


*Candida* esophagitis also associated with chronic mucocutaneous candidiasis, which is a congenital immunodeficiency state.

Diseases that interfere with esophageal peristalsis like achalasia, esophageal cancer and progressive systemic sclerosis may lead to fungal esophagitis.

Primarily, esophagitis caused by HPV is presented by small vesicle developments that rupture eventually forming superficial ulcers on the mucosa that are discrete in nature.

The host promotes healing of the ulcers in immunocompetent people. However in severely immusosuppressed people, the disease may progress from discrete areas of ulceration hemorrahgic esophagitis that is diffused. Candidiasis may heavily infect necrotic herpetic ulcers.

The esophagus is normally involved by erosion of concerned mediastinal lymph nodes abutting the esophagus in tuberculous esophagitis.

In addition, infection of the esophagus by bacteria occurs in the immunocompromised host, is usually polymicrobial, and derives from oral flora. This entity is underdiagnosed in severely granulocytopenic patients, given that bacteria are difficult to identify on routine histologic examination. In such patients, bacterial infection often coexists with viral or fungal organisms that are more readily detected. Suppression of gastric acid production (by proton pump inhibitors) may predispose to bacterial and fungal esophagitis. The diagnosis is made by endoscopic biopsy, and in these specimens, clusters of bacteria are mixed with necrotic epithelial cells. Treatment consists of broad-spectrum antimicrobial therapy.

Although infectious esophagitis is usually caused by fungal or viral organisms, other rare causes include Staphylococcus, Streptococcus, Klebsiella, Blastomyces, Cryptosporidium, *Torulopsis glabrata*, and *Lactobacillus acidophilus*.

### **4. Clinical presentation**

#### **4.1 Patient history**

The history findings vary based on the type of esophagitis. Esophageal food impaction can be the initial presentation of proton pump inhibitor (PPI)-responsive eosinophilic esophagitis [15].

#### **4.2 Symptoms**

Immunosuppressed people are prone to developing infectious esophagitis. Fungi like Candida organisms and viruses such as HPV and CMV are the most common causes of infectious esophagitis. The diagnosis of infectious esophagitis is supported by immunocompromisation, steroid treatment, systemic disease or recent antibiotic use. Whilst some people may not have any symptoms of infectious esophagitis, notable symptoms of the disease are [1–15]:

*Infectious Esophagitis DOI: http://dx.doi.org/10.5772/intechopen.99917*


As the symptoms of infectious esophagitis may mimic other diseases, it is important that proper investigation and diagnosis are made in order to have better outcome for the patients.

In people with one or more predisposing factors for *Candida* esophagitis, it is often manifested clinically by dysphagia and/or odynophagia. Symptoms differ in characteristics and features that differ in intensity like mild/moderate achalasia to severe odynophagia, which makes it very hard for sufferers to eat food or swallowing. Some people may develop retrosternal pain or bleeding in the gut. However, some people do not have any symptoms.

Esophagitis caused by HPV is commonly present in immunosuppressed people with AIDS, existing cancer or long term serious diseases or people that had received steroids, chemotherapy or radiation treatments [13–15]. In healthy people with no existing medical conditions, herpes esophagitis can sometimes occur as acute self-limiting disease. Acute onset of severe odynophagia is usually present in people with herpes esophagitis. Difficulty in swallowing, pain in the chest and bleeding in the upper gut are other presenting symptoms in herpes esophagitis.

The development of severe odynophagia, dysphagia or both in people with AIDS is as a result of the manifestation of CMV. Evidence of CMV infection may be present in other organs and tissues like the colon, retina and liver in infected people. Patients may develop fear of eating sometimes in cases of severe odynophagia.

People with ulcers due to HIV normally show acute onset of severe odynophagia, dysphagia or both. A characteristic maculopapular rash may be visible on the upper half of the body if the ulcers manifest at the time of seroconversion.

People with advanced pulmonary or mediastinal tuberculosis or in immunodeficiency that have disseminated tuberculosis or other mycobacterial illnesses develop tuberculous esophagitis.

#### **5. Diagnosis and differential diagnoses strategies**

In considering the diagnosis and differential diagnosis of infectious esophagitis, it would be important to look at the diagnostic considerations and diagnosis considerations for the different types of infectious esophagitis in order to have

understandings of the various issues to note for making decisions on the suitable treatments for better outcomes for the patients.

#### **5.1 Diagnostic considerations**

The possibility of a systemic illness causing the esophageal manifestations should always be considered (for example, AIDS, scleroderma, systemic lupus erythematosus (SLE) and pemphigus). Similarly, cardiac causes of chest discomfort should also be considered, and the appropriate treatment should be given. If the diagnosis is unclear, admission for further evaluation is suggested. Do not misdiagnose cardiac chest pain as esophageal pain. Pain can be similar, particularly in elderly patients and women.

Conditions that may mimic symptoms of esophagitis include the following [12–15]:


#### **5.2 Diagnosis considerations for the different types of infectious esophagitis**

The diagnosis considerations for the various types of infectious esophagitis are discussed below.

#### *5.2.1 Diagnosis of Candida esophagitis*

Reflux esophagitis, herpes esophagitis, superficial spreading carcinoma and glycogenic acanthosis, may produce findings similar to those seen in *Candida* esophagitis. However, it is also important to note that elderly people who do have any symptoms of the esophagus and the more rounded appearance of the mucosal nodules of glycogenic acanthosis do indeed present with glycogenic acanthosis, but the candidiasis plaques are more linear in appearance.

A nodular mucosa of reflux esophagitis can also be present in patients. However, the nodules are difficult to identify than those found in candidiasis, and they are normally infectious with the gastroesophageal junction.

Multiple plaquelike lesions in the gullet are sometimes due to herpes esophagitis, which is normally linked to small superficial ulcers. Cancers that are spreading superficially may also present as a nodular mucosa with poorly defined nodular borders, leading to a confluent area of disease.

The plaques of candidiasis may resemble the insoluble effervescent particles and debris in the gullet. Hence the performance of a double-contrast study should be undertaken without the use of effervescent granules if infectious esophagitis is suspected.
