4: Iatrogenic conditions

4

Iatrogenic conditions

An increasing number of therapeutic procedures important in modern medicine and surgery can produce iatrogenic (doctor-induced) unwanted orofacial complications (Tables 4.14.6).

Immunosuppressive therapy

Immunosuppressive therapy is designed to suppress T lymphocyte function, and leads to immunoincompetence and liability to infections, especially with viruses (Figures 4.14.3), fungi (Figure 4.4) and mycobacteria (Table 4.1).

Table 4.1

Orofacial complications of immunosuppression

Viral infections Herpesviruses (HSV, VZV, CMV, EBV, KSHV) and human papillomaviruses (HPV)
Fungal infections Usually with Candida species but also deep mycoses (e.g. zygomycosis, histoplasmosis)
Bacterial infections Especially with tuberculosis and other mycobacterial infections
Virally related malignant disease Kaposi sarcoma, lymphomas, carcinomas
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Figure 4.1 Herpes zoster (shingles) of the mandibular division of the trigeminal nerve.
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Figure 4.2 Herpes zoster (shingles) of the mandibular division of the trigeminal nerve.
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Figure 4.3 Wart (human papillomavirus infection).
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Figure 4.4 Candidosis can complicate systemic or local immunosuppression (from steroid inhalers, as here).

Such infections may spread rapidly; may be opportunistic; and may be clinically silent or atypical.

Radiotherapy

Radiation therapy is widely used, especially to control malignant neoplasms, and if involving the mouth and salivary glands invariably produces complications (Table 4.2). These complications may be minimized by using:

Table 4.2

Orofacial complications of radiotherapy

Condition Causes Comments
Mucositis After external beam radiotherapy involving the maxillofacial tissues Dose-dependent diffuse erythema and ulceration after 10–15 days (Figure 4.5)
Hyposalivation Damage to salivary glands (Figure 4.6) Can lead to dysphagia, disturbed taste, candidosis, sialadenitis and radiation caries
Osteoradionecrosis   Pain, jaw necrosis and infection
Trismus Inflammation and scarring Distinguish from tumour spread
Taste loss Damage to taste buds Temporary
Telangiectasia   Late
Jaw and tooth hypoplasia Abnormal development Children treated for neuroblastoma are at particularly high risk
Facial palsy Carotid artery damage Cerebrovascular event (stroke)
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Figure 4.5 Mucositis can produce widespread erosions and ulcers.
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Figure 4.6 Radiation-induced hyposalivation is invariable after radiation involving major salivary glands.
• minimal radiation doses and fields
• IMRT (intensity-modulated radio therapy) or IGRT (image-guided radiotherapy)
• mucosa-sparing blocks
• amifostine (a free radical scavenger) before therapy.

Chemotherapy

Chemotherapy is widely used, especially to treat lymphoproliferative conditions and malignant neoplasms. There can be several complications (Table 4.3). Mucositis is an almost invariable complication and may also be a predictor of gastrointestinal toxicity and of hepatic veno-occlusive disease. It is caused by cisplatin, etoposide, fluorouracil and melphalan, mucositis is especially seen with chemo-radiotherapy regimens, involving:

Table 4.3

Orofacial complications of chemotherapy

Condition Causes Comments
Mucositis Cytotoxic drugs impair the mucosal barrier and immunity Pain appears within 3–7 days, mucosa reddens and thins, may slough and become eroded and ulcerated and sometimes bleeds. Erosions/ulcers often become covered by a yellowish white fibrin clot termed a pseudomembrane
Taste sensation changed poor oral hygiene, gastric reflux, infections, drugs Often temporary
• cisplatin and fluorouracil
• cisplatin, epirubicin, bleomycin
• carboplatin.

Organ transplantation

Transplant recipients are treated with immunosuppressive therapy designed to suppress T lymphocyte function, and they therefore have an increased risk of infections and some malignant neoplasms (Table 4.4).

Table 4.4

Orofacial complications of organ transplantation

Viral infections Herpesviruses (HSV, VZV, CMV, EBV, KSHV) and human papillomaviruses (HPV),
Fungal infections Usually with Candida species but also deep mycoses (e.g. zygomycosis, histoplasmosis)
Bacterial infections Especially with tuberculosis and other mycobacterial infections. Bacterial sepsis is the most common cause of deaths occurring during the first post-transplantation months
Virally related malignant disease Kaposi sarcoma, lymphomas, carcinomas, post-transplant lymphoproliferative disease

Haematopoietic stem cell transplantation

Haematopoietic stem cell transplantation (HSCT or bone marrow transplant) is increasingly used to treat haematological conditions, neoplasms and some genetic defects. Patients are first profoundly immunosuppressed to minimize graft rejection by ‘conditioning’, often using cyclophosphamide, plus total body irradiation (TBI), or busulphan and are thus very susceptible to infections. Patients must be isolated and may require transfusions of granulocytes, platelets, red cells, granulocyte colony stimulating factors and antimicrobials until the donor bone marrow is functioning. HSCT may be complicated by mucositis, infections, neoplasms, bleeding, or graft-versus-host disease (GvHD) (Table 4.5).

Table 4.5

Orofacial complications of haematopoietic stem cell transplantation

Condition Causes Comments
Mucositis Cytotoxic drugs impair the mucosal barrier and immunity Pain appears within 3–7 days, mucosa reddens and thins, may slough and become eroded and ulcerated and sometimes bleeds. Erosions/ulcers often become covered by a yellowish white fibrin clot termed a pseudomembrane
Bleeding
Jan 12, 2015 | Posted by in Oral and Maxillofacial Pathology | Comments Off on 4: Iatrogenic conditions
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