​Kembara Xtra - Medicine - Pneumocystis Pneumonia

​Kembara Xtra - Medicine - Pneumocystis Pneumonia 
The fungus that causes pneumonia in humans was previously known as Pneumocystis carinii. Its name was officially changed to Pneumocystis jiroveci in 2001 after it was discovered that the fungus that infects humans is distinct from the fungus that infects animals. P. jiroveci is extremely resistant to conventional antifungal agents, including both amphotericin and azole.


Caution 
P. jiroveci pneumonia cannot be diagnosed by any combination of symptoms, signs, blood chemistries, or radiographic findings.


Epidemiology 
P. jiroveci is widespread throughout the world, and most kids have been exposed to it by the time they are 2 to 4 years old.
P. jiroveci's reservoir and mode of transmission are still unknown.
- Person-to-person transmission is the most likely way for an infection to spread in humans, according to research, which favor an airborne transmission model.
Incidence
HIV-infected infants have a high death rate, with a median survival of only one month. Infants with HIV infection have a peak incidence of PCP between 2 and 6 months.
Prevalence
The percentage of healthy persons who have P. jiroveci colonization ranges from 0 to 20%.
Recent research has shown that P. jiroveci colonization in immunocompetent, asymptomatic patients is transitory.
50% of PCP patients have concurrent infections with two P. jiroveci strains.
There is evidence that in patients who experience numerous episodes of PCP, different strains are in charge of each episode.


Pathophysiology and Etiology 

Unknown method of spread; likely respiratory from infected host 

Risk Elements 

Patients at risk include those with HIV infection, especially if they are not receiving prophylactic treatment for PCP, those taking high doses of glucocorticoids, those with immune system changes unrelated to HIV, those taking chronic immunosuppressive drugs, and those with hematologic or solid malignancies that cause immune depression related to malignancy.

Prevention 
HIV-positive adults with prophylactic indications (3)  Should begin if the patient develops oropharyngeal candidiasis or when the CD4 count reaches 200 cells/L. - Children with HIV (3) Based on recommendations for adults, prophylaxis should be given to children under the age of 6.
Start when the CD4 count is 500 cells/L for children aged 1 to 5 years, and start at 15% for infants under 12 months.
- PCP prophylaxis should be administered to non-HIV-infected persons who are using immunosuppressive medicines or who have underlying immune system deficiencies, but there are no current recommendations on when to begin this.
Medication: Trimethoprim-sulfamethoxazole (TMP-SMX) Adults: 1 double-strength tablet daily or 1 double-strength tablet three times per week Children >2 months: TMP 150 mg/kg/day in divided doses every 12 hours for three days each week - Suspension of atovaquone
 1,500 mg PO once daily with meals for adults
1 to 3 months: 30 mg/kg/day PO once daily; 4 to 24 months: 45 mg/kg/day PO once daily; >24 months: 30 mg/kg/day PO once daily; adolescents 13 years: refer to adult dose. Children should not take more than 1,500 mg/day.
Adults only: 50 mg BID or 100 mg once daily for Dapsone.
Pentamidine: Adults only: 300 mg aerosolized every four weeks; termination of prophylaxis when CD4+ cell counts in the adult population reach 200 cells/L for three months; there are no specific recommendations for ceasing prophylaxis in children.

Accompanying Conditions 
Chronic obstructive pulmonary disease (COPD), HIV infection, interstitial lung disease, connective tissue illnesses treated with corticosteroids, cancer patients receiving immunosuppressive therapy, and organ transplant recipients DISEASE HISTORY
HIV-positive individuals: Subacute onset over several weeks; dyspnea that gets worse with time; tachypnea
Low-grade fever, chills, weakness, exhaustion, and a general feeling of unwellness. Non-HIV immunocompromised people have more abrupt onset with fulminant respiratory failure.
Rapid tachypnea and dyspnea, a fever, and a dry cough

Clinical examination reveals a fever, tachypnea, tachycardia, and a normal or nearly-normal lung examination.

Differential diagnosis includes bacterial pneumonia, fungal pneumonia, viral pneumonia, tuberculosis, and others.


Laboratory Results 

It is impossible to culture P. jiroveci. Therefore, a diagnosis depends on the organism being found using a polymerase chain reaction (PCR), colorimetric or immunofluorescent staining, or both.
ABG demonstrates hypoxemia and a varying alveolar-arterial gradient depending on the disease's severity. LDH: There is typically an elevation in serum lactate dehydrogenase (non-specific; possibly brought on by underlying lung inflammation and damage).
The average CD4 cell count in HIV-infected PCP patients is 200 cells/L.
S-adenosylmethionine concentrations are considerably lower in PCP patients. As a treatment is successful, the levels rise.
A detailed metabolic profile Chest radiograph (CXR) As the severity of the infection increases, there are bilateral, symmetric, fine, reticular interstitial infiltrates in the perihilar zones that become more homogeneous and diffuse. Less frequent patterns include pneumothoraces, solitary or numerous nodular opacities, lobar infiltrates, upper lobe involvement in patients receiving aerosolized pentamidine, and pneumatoceles.
- In as many as 30% of PCP patients, it may be normal.
Compared to CXR, high-resolution CT is more sensitive.

Other/Diagnostic Procedures
The best diagnostic method for obtaining samples for direct fluorescent antibody staining is fiberoptic bronchoscopy with bronchoalveolar lavage (BAL).
- The range of sensitivities is 89% to >98%.
Using traditional stains, it is possible to identify Pneumocystis trophic forms or cysts that were acquired from induced sputum, BAL fluid, or lung tissue. PCR can identify Pneumocystis from respiratory sources, although there is still a risk of false positive results.


Management 
Patients with and without AIDS are given different treatment schedules for different lengths of time: The typical course of treatment for PCP patients without AIDS is 14 days.
The danger of relapse after just 14 days of treatment led to the extension of PCP treatment for AIDS patients to 21 days.


First Line of Medicine
TMP-SMX[C]
Adult dosage (TMP): 4 doses of 15 to 20 mg/kg/day, either orally or intravenously.
Children's dosage (>2 months)
- TMP: 15 to 20 mg/kg/day divided into 6 to 8-hour intervals.
TMP-SMX dosages for patients with renal insufficiency should be decreased.
Patients should undergo therapy for 21 days.
 It frequently takes at least 7 to 10 days after starting Pneumocystis medication for clinical improvement to be noted.
Category C risk factor for pregnancy
There is a rise in PCP that is resistant to medication, particularly when used to treat TMP-SMX.

Next Line
Pentamidine (for situations that are moderate to severe) Dapsone + trimethoprim (adults only) - Dapsone 100 mg PO once daily, plus - Trimethoprim 5 mg/kg PO TID - Check the glucose-6-phosphate dehydrogenase level before to starting dapsone because hemolysis may occur. - Adults and children: 4 mg/kg IV or IM once daily.
Atovaquone - Adults: 750 mg PO BID (>13 years of age) - Children: 40 mg/kg/day PO divided BID (max 1,500 mg) Clindamycin + primaquine (adults only) - Clindamycin 600 to 900 mg IV q8h or 300 to 450 mg PO QID plus - Primaquine 30 mg PO once daily
It should be noted that pentamidine is more toxic than TMP-SMX, causing hypotension, hypoglycemia, and pancreatitis.

Further Treatments 
Adjunctive corticosteroids, such as prednisone or methylprednisolone, have been demonstrated to be beneficial for people with HIV and moderate to severe PCP symptoms.
HIV patients who have hypoxemia—defined as a partial pressure of arterial oxygen 70 mm Hg or an alveolar-arterial gradient >35 mm Hg on room air—benefit most from corticosteroids.
 Prednisone, 40 mg PO BID on days 1 through 5, 40 mg daily on days 6 through 11, and 20 mg daily on days 12 through 21 for adults and adolescents over the age of 13.

No clear standards exist for hospital admittance. Five factors that can predict death in HIV-related Plague caused by pneumocystis- The patient's age has increased - Recent IV medication usage - Total bilirubin is greater than 0.6 mg/dL - Serum albumin is below 3 g/dL - Alveolar-arterial oxygen gradient is below 50 mm Hg

Constant Care 

Patients with HIV/AIDS should undergo lifetime secondary prophylaxis if they have experienced PCP in the past, unless they are responding well to highly active antiretroviral therapy (HAART) and have a CD4 count >200 cells/L for at least three months.
Patient Monitoring With treatment, serum lactate dehydrogenase levels, pulmonary function test outcomes, and ABG readings usually return to normal.

Diet 

No need for a special diet

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