Cryptococcus meningitis Flashcards

1
Q

Cryptococcal meningitis commonly occurs in patients with _________

A

Late stage HIV-infection

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2
Q

Cryptococcosis is an illness caused by infection with Cryptococcus fungi in your _______ or _______. It can also spread to many areas of your body (_________ ________).

A

Cryptococcosis is an illness caused by infection with Cryptococcus fungi in your brain or lungs. It can also spread to many areas of your body (disseminated cryptococcosis).

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3
Q

When you have a Cryptococcus infection in your brain, it’s called _____________

A

When you have a Cryptococcus infection in your brain, it’s called cryptococcal meningitis

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4
Q

Cryptococcus infection in lungs is called __________

A

In lungs, it’s sometimes called cryptococcal pneumonia or pulmonary cryptococcosis.

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5
Q

What causes cryptococcosis?

A

The fungi Cryptococcus gattii (C. gattii) and Cryptococcus neoformans (C. neoformans) cause cryptococcosis. They live in the environment — in dirt (soil), on trees and in bird poop.

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6
Q

Clinical features of cryptococcal meningitis

A

fever, headaches and neck stiffness

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7
Q

Diagnose of CM

A

CSF analysis ( culture, screening for cryptococcal antigen) definite diagnosis

Serum cryptococcal antigen test (CAT) and blood cultures

Indian ink

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8
Q

Cellular and biochemical response in cryptococcal meningitis include:

A

CSF proteins are greater than 0.4g/L ( 1-3 g/L)

CSF blood glucose is less than 50%

predominantly mononuclear leucocytes (lymphocytes)

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9
Q

How many phases are there in the treatment CM?

A

3
Induction therapy
Consolidation therapy
Maintenance therapy

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10
Q

Goals of therapy

A

To rapidly control the infection and stabilise the patient to minimise morbidity and mortality

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11
Q

Induction therapy:

A

•2 weeks therapy of intravenous amphotericin B deoxycholate (0.7 – 1mg/kg/day) ± flucytosine (100mg/kg/day i.v or p.o in divided doses

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12
Q

Addition of flucytosine results in ____________________________________________________________________________________

A

Addition of flucytosine results in quicker clearance of yeasts from the CSF( due to synergism) and reduces the relapse rate in patients not on HAART but associated with additional toxicity

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13
Q

Consolidation therapy:

A

Fluconazole 400mg/day p.o for at least 8–10 weeks.

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14
Q

Maintenance therapy (_________________):

A

Maintenance therapy (reduces incidence of relapse):
•Fluconazole 200mg daily p.o continued for life, or until immune function restored( CD4 count > 100cells/mm3 + undetectable viral load for 3 months)

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15
Q

Types of amphotericin B

A

Lipid formulations of amphotericin B e.g. liposomal amphotericin B, at doses of 4 – 6mg/kg/day have comparable efficacy to, and fewer side effects, than conventional amphotericin B at a dose of 0.7mg/kg/day.

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16
Q

Premedication

A

Promethazine 25mg i.v ( to prevent nausea and vomiting)

•Hydrocortisone 25 – 50mg may be added to the infusion solution( to control anaphylactoid reactions-Anaphylactoid reactions are immediate systemic reactions that mimic anaphylaxis but are not caused by IgE-mediated immune responses. )

•Premedication prevents chills, fever and tachypnoea - rapid breathing)

•Pre – and post amphotericin B sodium loading with 1L normal saline to prevent hypotension and nephrotoxicity (electrolyte derangements)

•Antipyretics e.g. paracetamol

17
Q

Amphotericin B administration

A

Amphotericin B deoxycholate is given by slow IV infusion in dextrose 5% over 2 – 4 hours

•Amphotericin B should not be given in electrolyte – containing fluids ( normal saline, dextrose normal saline, ringers lactate) as it will precipitate out.

•Concentration of amphotericin B should be 0.1mg/mL

pH of dextrose 5% must not be below 4.2 (inactivated at low pH values)

-Should be protected from light (disrupt colloidal suspension)…cover with aluminium foil

18
Q

Adverse effects of Amphotericin B

A

•Infusion related: avoid rapid infusion (risk of arrhythmias)
•Chills
•fever
•Nausea and vomiting
•hypotension
•Headache
•rigors

Non – infusion related:
•Nephrotoxicity(most serious) .i.e. causes acute tubular necrosis e.g. hypokalemia and hypomagnesemia (increased urinary excretion of potassium and magnesium)
– monitor renal function on alternate days
- Discontinue if serum creatinine > 250µmol/L until Cr levels fall below this limit
•Azotaemia (uraemia) observed after first few infusions

Thrombophlebitis (irritates venous endothelium)
•Abnormal liver function (discontinue treatment).
•Blood disorders (inhibits erythropoiesis)

19
Q

Amphotericin B lipid formulations

A

Advantages of the expensive lipid formulations delivered as amphotericin encapsulated in liposomes or a complex with lipid molecules:

•Higher unit doses can be given

•Reduction in toxicity

20
Q

Flucytosine

A

Synthetic fluorinated nucleotide analogue
Mode of action
•Following uptake by the cell (dependent on presence of cytosine permease), flucytosine is deaminated to 5-fluorouracil by cytosine deaminase)
•5 – fluorouracil is incorporated into fungal RNA in place of uracil, impairing protein synthesis.
•A metabolite of 5 – fluorouracil inhibits thymidylate synthetase leading to inhibition of DNA synthesis.
•Host cells have absent or weak cytosine deaminase activity ( selective toxicity of flucytosine)

Side effects
•Dose – related myelosuppression with neutropenia and thrombocytopenia
•Hepatoxicity
•Teratogenicity