Hypersensitivity pneumonia

Radiographic features of HP are variable depending on the phase of the disease (i.e., acute, subacute, or chronic) (97-102) (Table 12). HRCT scans in acute HP reveal GGO and areas of airspace consolidation (99,100) (Fig. 13). The process is usually diffuse and symmetrical, but patchy or asymmetric involvement may occur (100). The cardinal CT feature of subacute HP is small (2-4 mm), poorly defined centrilobular micronodules (99,103). Additional features include GGO, 

Diffuse ground glass opacities Airspace consolidation Subacute HP 

Predilection for middle or upper lung zone predominance Mosaic pattern (air trapping) 

Honeycomb change Architectural distortion Micronodules Ground glass opacities Emphysema 

Abbreviations. HRCT, high-resolution computed tomography HP, hypersensitivity pneumonitis. 

---

In addition to the proteins discussed above, a large number of reactive chemicals used in industry can cause asthma and rhinitis. Hypersensitivity pneumonias have also been described. Isocyanates and acid anhydrides are industrial chemicals that cause occupational asthma. Acid anhydrides, such as phthalic anhydride, seem to cause mainly type I reactions, whereas the IgE-mediated mechanism explains only a part of the sensitizations to isocyanates. Several mechanisms have been suggested, but despite intensive research no models have been generally accepted. The situation is even more obscure for other sensitizing chemicals therefore, the term specific chemical hypersensitivity is often used for chemical allergies. This term should not be confused with multiple chemical sensitivity (MCS) syndrome, which is a controversial term referring to hypersusceptibility to very low levels of environmental chemicals. ... 

Building Related Illness (BRI) Refers to an illness brought on by exposure to contaminants in a building. Legionnaires disease and hypersensitivity pneumonia remain two commonly occurring examples. 

Johnson, C.L., Bernstein, I.L., Gallagher, J.S., Bonventre, P.F. and Brooks, S.M. (1980). Familial hypersensitivity pneumonia induced by Bacillus subtilis, American Review of Respiratory Disease, 122, 339-348. 

Gl dysmotility Esophageal dysmotility and aspiration have been associated with antipsychotic drug use. Use quetiapine, ziprasidone, risperidone, olanzapine, aripiprazole, and others cautiously in patients at risk for aspiration pneumonia. Hypersensitivity reactions Patients who have demonstrated a hypersensitivity reaction (eg, blood dyscrasias, jaundice) with a phenothiazine should not be re-exposed to any phenothiazine unless the potential benefits of treatment outweigh the possible hazards. 

Local injection site reactions The most common adverse events associated with enfuvirtide use are local injection site reactions. Manifestations may include pain and discomfort, induration, erythema, nodules and cysts, pruritus, and ecchymosis. Pneumonia An increased rate of bacterial pneumonia was observed in subjects treated with enfuvirtide in the phase 3 clinical trials compared with the control arm. Hypersensitivity reactions Hypersensitivity reactions have been associated with enfuvirtide therapy and may recur on rechallenge. Hypersensitivity reactions have included individually and in combination Rash, fever, nausea and vomiting, chills. 

Erythromycin is effective in the treatment and prevention of S. pyogenes and other streptococcal infections, but not those caused by the more resistant fecal streptococci. Staphylococci are generally susceptible to erythromycin, so this antibiotic is a suitable alternative drug for the penicillin-hypersensitive individual. It is a second-line drug for the treatment of gonorrhea and syphilis. Although erythromycin is popular for the treatment of middle ear and sinus infections, including H. influenzae, possible erythromycin-resistant S. pneumoniae is a concern. 

Rare reactions include hypersensitivity reactions, malignancies, respiratory tract infections, bronchitis, UTls, and more serious infections (such as pneumonia, tuberculosis, cellulitis, pyelonephritis, and septic arthritis). 

Rare reactions include hypersensitivity reactions, lymphopenia, malignancies, and serious infections requiring hospitalization (such as abscess, pneumonia, and postoperative wound infection),... 

Hypersensitivity reaction, malignancies, serious infections (abscess, cellulitis, postoperative wound infection, pneumonia), thrombocytopenia, and worsening of psoriasis occur rarely. 

Cefazolin penetrates well into most tissues. It is a drug of choice for surgical prophylaxis. Cefazolin may be a choice in infections for which it is the least toxic drug (eg, penicillinase-producing E coli or pneumoniae) and in persons with staphylococcal or streptococcal infections who have a history of penicillin allergy other than immediate hypersensitivity. Cefazolin does not penetrate the central nervous system and cannot be used to treat meningitis. Cefazolin is an alternative to an antistaphylococcal penicillin for patients who are allergic to penicillin. 

The most common adverse effects associated with enfuvirtide therapy are local injection site reactions. Hypersensitivity reactions may rarely occur, are of varying severity, and may recur on rechallenge. Eosinophilia has also been noted. In one prospective clinical trial, an increased rate of bacterial pneumonia was noted in patients receiving enfuvirtide. No interactions have been identified that would require the alteration of the dosage of other antiretroviral drugs. 

Melphalan can cause an acute interstitial pneumonia with hypoxemia (3). This is probably due to a hypersensitivity mechanism and should be distinguished from fibrosing pneumonitis, which melphalan can also cause (4). 

Immunoallergic reactions have been reported with minocycline and include lupus-like syndrome, autoimmune hepatitis, eosinophilic pneumonia, hypersensitivity syndrome, a serum sickness-like illness (29), and Sweet s syndrome (SEDA-21, 262) (SEDA-22, 271). Over 60 minocycline-induced cases of lupus-like syndrome and 24 cases of minocycline-induced autoimmune hepatitis were found in a review of the literature (30). In 13 patients, both disorders co-existed. These patients had symmetrical polyarthralgia/polyarthritis, raised liver enzymes, and positive antinuclear antibodies they were also generally antihistone-negative, and only two patients had p-ANCA antibodies. Minocycline-related lupus can also occur in adolescents (31). 

Acute lung reactions to nitrofurantoin are extremely rare in children (12). Lung tissue findings in acute reactions have shown minor vasculitis, granulomatous vasculitis (hypersensitivity angiitis), proliferation of endothelial cells, and empty alveoli (13). Rapidly progressing bronchiolitis obliterans with organizing pneumonia (BOOP) has been reported (14). 

In a single-arm, open, prospective study between 1990 and 1995 (before HAART) the prophylactic efficacy of Fansidar was evaluated in 95 HIV-infected patients with successfully treated Pneumocystis proved pneumonia and no history of Toxoplasma encephalitis (3). Patients took Fansidar with folinic acid (15 mg) twice weekly and were followed for a median of 19 (range 1-72) months. Five patients had a Pneumocystis relapse, but three had not taken their therapy. Of the 69 patients positive for. r. t. -Toxoplasma IgG antibodies, only one developed toxoplasma encephalitis after 50 months. A rash developed in 16 patients after a median of 3 weeks, and required withdrawal in six. Two developed Stevens-Johnson syndrome after three or four doses. There was no significantly increased risk of adverse reactions to Fansidar in patients with previous hypersensitivity reactions to co-tri-moxazole. The results of this study are of particular relevance to areas in which HAART is unavailable and where the antimalarial activity of Fansidar may confer additional benefit. 

The safety and efficacy of a fixed combination of pyrimethamine 25 mg + sulfadoxine 500 mg, supplemented with folinic acid 15 mg, both twice a week, as primary prophylaxis of Pneumocystis pneumonia and Toxoplasma encephalitis has been evaluated in 106 patients infected with HIV in a single-arm, open, prospective study (17). There were allergic reactions in 18 patients and permanent withdrawal was required in seven. One patient who took continued prophylaxis despite progressive hypersensitivity reactions developed a serious adverse reaction (Stevens-Johnson syndrome). 

Respiratory reactions to sulfonamides include migratory pulmonary infiltrates, chronic pneumonia, asthma, and pulmonary angiitis. These reactions are thought to be mainly due to hypersensitivity, although the precise mechanisms are not well understood (14-16). The link to the drug has been proven in most cases by recurrence after re-exposure to the same sulfonamide or to co-trimoxazole. 

In an open prospective study in 95 HIV-infected patients with successfully treated Pneumocystis proved pneumonia, pyrimethamine + sulfadoxine (25/500 mg) was given twice weekly to prevent relapse (159). There were allergic skin reactions in 16 patients, resulting in permanent withdrawal in six. Two patients developed serious adverse reactions (Stevens-Johnson syndrome), both of whom had continued to take prophylaxis despite progressive hypersensitivity reactions. 

No diagnostic tests are available to confirm sulfonamide hypersensitivity, and while avoidance of the drug is generally appropriate when a previous hypersensitivity reaction is suspected, desensitization protocols are available for use in HIV patients in whom Pneumocystis proved pneumonia prophylaxis or treatment is indicated (193). 

Starting in the 1920s, very many different mixed bacterial vaccine products (including inactivated bacteria such as Staphylococcus aureus. Streptococcus species. Streptococcus pneumoniae, Moraxella catarrhalis, Klebsiella pneumoniae, H. influenzae) were marketed worldwide. Currently, there are still several products available in European countries, and one product in the USA. Most vaccines have been used for treatment of recurrent and chronic infections of the respiratory tract. The efficacy of these products is doubtful. Delayed hypersensitivity to bacterial products is common. Delayed reactions, sometimes associated with vague malaise or myalgia, can occur after the administration of maintenance doses for months. If delayed skin reactions are accompanied by any systemic symptoms, administration of the mixed vaccine should be drastically reduced or stopped (87). 

The pathology of the infection is due to inflammatory changes associated with an induced autoimmune demyelination of nerve cells. Interestingly, the immunosuppressive action of components of the parasite s membrane are probably responsible for frequent secondary infections such as pneumonia. Liberation of common surface antigens (the mechanism involved in immune evasion) in every trypanolytic crisis (episode of trypanosome lysis) leads to antibody and cell-mediated hypersensitivity reactions. It is believed that some cytotoxic and pathological processes are the result of biochemical and immune mechanisms. 

Trimethoprim-sulfamethoxazole is used frequently for preventive or active treatment of Pneumocystis carinii pneumonia in patients with the AIDS. Adverse reactions to trimethoprim-sulfamethoxazole have been observed to occur much more frequently in these patients compared with those without AIDS. Adverse effects to trimethoprim-sulfamethoxazole occur in 50% to 80% of AIDS patients compared with 10% of other immunocompromised patients. Trimethoprim-sulfamethoxazole was associated with an adverse-event rate of 26.3 per 100 person-years and hypersensitivity events at 22 per 100 person-years. Adverse-event rate was related to lower CD4+ cell count. When the CD4+ cell count was less than 100/mm , the adverse drug event rate was 31 per 100 person-years. ... 

HEALTH SYMPTOMS inhalation (conjunctiva irritation, discharge of tears, cough, unspecified respiratory system effects, irritates eyes, skin and mucous membranes) skin and/or eye contact (skin redness, redness of eyelids, skin vesiculation, dermatitis) skin absorption (headache, hypersensitivity reactions, bronchospasm) ingestion (pneumonia, heart failure, hepatocellular damage). 

ACUTE HEALTH RISKS lacrimation headache contact bums to the eyes and skin conjunctivitis erythemic eyelids bronchospasm laryngospasm hypersensitivity reaction pulmonary edema irritation of throat cough chest constriction erythema (skin redness) vesiculation of skin pneumonia heart failure. 

---