Infection CPC Flashcards
What may patients with PCP pneumonia present with?
Old
HIV
COPD
Patchy consolidation on CXR
What is the typical picture of PCP pneumonia?
CXR fairly normal, CT ground-glass, SoBOE (SpO2 tends to drop on exertion more)
Widespread, bilateral ground glass shadowing with reduced exercise tolerance and low saturations is suggestive of Pneumocystis jirovecii pneumonia (PCP pneumonia)
How do you treat PCP pneumonia?
Co trimoxazole
How do you treat a PCP rash?
OD prednisolone
What is the second line treatment for PCP?
Clindamycin
Primiquine (G6PD norm)
IV methylprednisolone
What other conditions may be associated with HIV?
oral candidiasis (given fluconazole) seborrhoeic dermatitis
CD4 51 (start treatment <250 cells), CD4% 7.9%. Viral Load 250000
What is the stain used for cytology of HIV?
Visualised using a methenamine silver stain (Grocott-Gomori)
What is the natural history of HIV?
· Seroconversion -> symptoms (e.g. fever, rash)
· Eventually, viral load will fall and CD4 count will recover HIV tends to target the GALT
· Then you will be asymptomatic, which can last for years
· Eventually, viral load will rise and the CD4 count will fall
· You become immunocompromised and will be at risk of AIDS-defining conditions such as PJP/PCP
· CD4+ count is a major determinant of immune damage and predicts short term outlook
What causes infections in the immunodeficient?
o Common agents (e.g. pneumococcus)
o Uncommon infectious agents (often ubiquitous but cause no problem in immunocompetent patients)
§ Atypical mycobacteria Fungal
§ Viral (CMV, HSV [i.e. reactivation]) Other (e.g. toxoplasmosis)
How do illnesses present in the immunodeficient?
o Normally, the symptoms of an illness are due to the immune response rather than the pathogen itself
o So, the presentation in HIV can be quite abnormal (due to immune compromise)
§ I.E. they may present with TB meningitis or miliary TB
o Speed of progression may also be different
What are the causes of immunodeficiency?
o Inherited
o Acquired
§ Iatrogenic
· Immunosuppressive agents
o Steroids
· Chemotherapy
· Radiotherapy
§ HIV
§ Chronic illness (diabetes, cancer)
§ Malnutrition
What do alcoholics get?
ctinomyces Lung Abscess
o Gram-positive rod that branches
o Causes lung abscesses in immunocompromised patients
o Closely associated with Nocardia
o These infections tend to be indolent, go on for a long time, and are very difficult to treat
§ This means it is hard to grow in the labs so, notify the histopathologist and microbiologist that you are worried about actinomyces so they can start growing ASA
What is the general management of osteomyelitis?
o Antimicrobial therapy alone is NOT curative in most cases of osteomyelitis
o Continuous drug over a long period of time will lessen the amount of discharge, but it will not cure the disease because it cannot sterilise dead bone or cavities with necrotic content and rigid walls
o Removal of devitalised tissues and prevention of extension of infection with adequate drainage is important
o Fibrous capsules can form which makes it impenetrable to ABx and it becomes a chronic source of infection
How do you deal with prosthetic joint infections?
· Removal of prosthesis and adequate debridement is the MOST IMPORTANT part of treatment
· Antibiotics play a secondary role (NOTE: in this case, the organisms remained sensitive to antibiotics for months, however, treatment failed due to the presence of infected prosthetic material and inadequate debridement)
· However, the consequences of aggressive debridement must be considered (it carries significant morbidity)
What are other iatrogenic sources of infection?
o Intravascular lines (e.g. venflons, central lines, PICC lines)
o Prosthetic heart valves (ends of the valves are poorly vascularised so it is difficult to treat infection)
o Prosthetic implants (e.g. cosmetic or reconstructive)
