Pneumocystis Pneumonia

Question 1

What organism causes pneumocystis pneumonia?

Answer 1

Pneumocystis jirovecii (previously Pneumocysits carinii)

Question 2

What type of organism is P.jirovecii?

Answer 2

Pneumocystis jirovecii is a yeast-like fungus

It can be visualized with silver staining (methenamine silver)

Question 3

What other pathology should be considered in a patient who tests positive for pneumocystis pneumonia?

Answer 3

AIDS or other condition causing significant immunosuppression

Question 4

What investigation is used to determine pneumocystis pneumonia severity?

Answer 4

ABG

Question 5

What is the treatment of choice for mild to moderate pneumocystis pneumonia?

Answer 5

FIRST LINE:
- co-trimoxazole (TMP-SMX) high dose

SECOND LINE:

• atovaquone
• dapsone + trimethoprim (oral); unlicensed
• clindamycin + primaquine (oral); associated with considerable toxicity

Question 6

What is the treatment of choice for severe pneumocystis pneumonia?

Answer 6

FIRST LINE:
- co-trimoxazole (TMP-SMX) high dose PO or IV infusion

SECOND LINE:
- pentamidine IV infusion; potentially toxic, can causes severe hypotension

*corticosteroid treatment can also be used in severe pneumocystis pneumonia and can often be life saving

Question 7

What adjunctive therapy may be used in moderate to severe pneumocystis pneumonia associated with HIV?

Answer 7

Prednisolone, oral (alternatively hydrocortisone parenterally) for 5 days, ideally started at the same time as anti-pneumocystis therapy but certainly no later than 24-72 hours afterwards

The dose is then reduced to complete 21 days of treatment and should be withdrawn before anti-pneumocystis treatment is complete

Question 8

In which patients is pneumocystis pneumonia prophylaxis offered? (2)

Answer 8

1. Patients with a history of infection
2. Patients who are severely immunocompromised

• Prophylaxis should continue until immunity recovers sufficiently. It should not be discontinued if the patient has oral candidiasis, continues to lose weight, or is receiving cytotoxic therapy or long-term immunosuppressant therapy

Question 9

What is the treatment of choice for pneumocystis pneumonia prophylaxis?

Answer 9

FIRST LINE:
- co-trimoxazole oral (TMP-SMX), given daily OR on alternate days ie 3 times a week; dose may be reduced to improve tolerance

SECOND LINE:

• inhaled pentamidine (better tolerated than parenteral pentamidine); patients may be prone to extra pulmonary infection
• dapsone
• atovaquone (unlicensed)

Question 10

Co-trimoxazole should be discontinued immediately if which rare but serious side effects develop? (6)

Answer 10

1. Leukopenia
2. Thrombocytopenia
3. Megaloblastic anemia
4. Eosinophilia
5. Stevens-Johnson syndrome
6. Toxic epidermal necrolysis

Question 11

Is co-trimoxazole safe to use in pregnancy?

Answer 11

No, trimethoprim is a folate antagonist and is therefore associated with teratogenic risk in the first trimester and neonatal hemolysis and methemoglobinemia in the third trimester

Question 12

Is co-trimoxazole safe to use in patients with hepatic impairment?

Answer 12

Avoid in severe liver disease

Question 13

What is co-trimoxazole?

Answer 13

Combination of trimethoprim and sulfamethoxazole (1:5 ratio)

Question 14

What is the main contraindication to co-trimoxazole?

Answer 14

Acute porphyrias

Caution if blood disorders, elderly, G6PD deficiency, predisposition to folate deficiency, and infants under 6 weeks

Question 15

What electrolyte imbalances are associated with co-trimoxazole use? (2)

Answer 15

Hyperkalemia

Hyponatremia

Question 16

What is the length of treatment with co-trimoxazole for pneumocysits pneumonia?

Answer 16

14-21 days PO or IV infusion (oral route preferred for children)