Pneumonia in Immunocompromised Host:-

1. Pneumonia in Immunocompromised Host:- Pneumonia in an immunocompromised host describes a lung infection that occurs in a person whose ability to fight infection is greatly reduced. Causes People who are immunocompromised have a defective immune response. Because of this, they are susceptible to infections by germs that typically do not cause disease in healthy people. They are also more vulnerable to the usual causes of pneumonia, which can affect anyone.

2. immunosuppression can be caused by: • Bone marrow transplantation • Certain medications (including steroids and those used to treat cancer ) • HIV infection • Leukemia • Organ transplant

3. Symptoms of pneumonia • Cough (may be dry or produce mucus-like, greenish, or pus-like sputum) • Chills with shaking • Easy fatigue • Fever • General discomfort, uneasiness, or ill feeling (malaise ) • Headache • Loss of appetite • Nausea and vomiting • Sharp or stabbing chest pain that gets worse with deep breathing or coughing • Shortness of breath • Other symptoms that may occur: • Excessive sweating or night sweats • Joint stiffness (rare) • Muscle stiffness (rare) • Swollen gland

4. The most IMP organism Gram-negative bacteria especiaaly pseudomenous aerugenosa fungi (Aspergillus) herpes simplex virus, cytomegalovirus Pneumocystitis carinii pneumonis M .bacterium tuberculosis

5. Treatment :- • Oxygen administration • Oxygen saturation and cardiac monitoring • Empiric antimicrobial therapy • Chest physiotherapy

6. Management of pneumonia in the immunocompromised patient • Antibiotic rationale :- • Treatment must be initiated rapidly as disease progression can be swift.  • Empirical treatment must take into account: • Local pathogens and their resistance patterns • The possibility of pseudomonal infections • The broad-range of potential pathogens including atypical pathogens • In the HIV-positive patient, infections such as Pneumocystis carinii should be considered.

7. Medication:- The 2 goals of pharmacologic therapy are eradication of infections and prophylaxisagainst common pathogens in high-risk patients. 1- Inpatient, non-ICU treatment * Respiratory fluoroquinolone * Beta-lactam plus a macrolide 2- Inpatient, ICU treatment *Beta-lactam plus either azithromycin or fluoroquinolone *For community-acquired methicillin-resistant Staphylococcus aureus infection, add vancomycin or linezolid * For Pseudomonas infection, 1-antipneumococcal, antipseudomonal beta-lactam plus either ciprofloxacin or levofloxacin (750-mg dose) 2- beta-lactam plus an aminoglycoside and azithromycin 3- a beta-lactam plus an aminoglycoside and an antipneumococcal fluoroquinolone.

8. Pneumocystis jiroveci Pneumonia (PCP) -Trimethoprim-sulfamethoxazole (TMP-SMX) is the treatment of choice (AI). (so imp) The dose must be adjusted for abnormal renal function. Adding leucovorin to prevent myelosuppression during acute treatment is not recommended because of questionable efficacy and some evidence for a higher failure rate (DII). Oral outpatient therapy of TMP-SMX is highly effective among patients with mild-to-moderate disease (AI). Mutations associated with resistance to sulfa drugs have been documented, but their effect on clinical outcome is uncertain. Patients who have PCP despite TMP-SMX prophylaxis are usually effectively treated with standard doses of TMP-SMX (BIII).

9. -Patients with documented PCP and moderate-to-severe disease, should receive corticosteroids as early as possible, and certainly within 72 hours after starting specific PCP therapy (AI). If steroids are started at a later time, their benefits are unclear, The preferred corticosteroid dose and regimen is prednisone 40 mg by mouth twice a day for days 1 to 5, 40 mg daily for days 6 to 10, and 20 mg daily for days 11 to 21 (AI). Methylprednisolone at 75% of the respective prednisone dose can be used if parenteral administration is necessary.

10. Alternative therapeutic regimens include (less imp 1-5) 1-dapsone and TMP for mild-to-moderate disease (BI) (this regimen may have similar efficacy and fewer side effects than TMP-SMX but is less convenient because of the number of pills) 2- primaquine plus clindamycin (BI) effective in mild-to-moderate disease, the clindamycin component can be administered intravenously for more severe cases; primaquine is only available orally) . 3-intravenous pentamidine (AI) (second choice for severe disease) 4- atovaquone suspension (BI) (this is less effective than TMP-SMX for mild-to-moderate disease but has fewer side effects)

11. 5- trimetrexate with leucovorin (BI) (this is less effective than TMP-SMX but can be used if the latter is not tolerated and an intravenous regimen is needed). Leucovorin must be continued 3 days after the last trimetrexate dose. The addition of dapsone, sulfamethoxazole, or sulfadiazine to trimetrexate might improve efficacy on the basis of the sequential enzyme blockade of folate metabolism, although no study data exist to confirm this (CIII).. Aerosolized pentamidine should not be used for the treatment of PCP because of limited efficacy and more frequent relapse

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