Infections of the compromised host

Year 3 Semester 2

2007/08 Batch

Faculty of Medicine

University of Peradeniya

Sri Lanka

Following topics will be discussed.

1. Chronic diarrhoea in post transplanted patient2. Haemorrhagic Chicken Pox3. Sepsis in a baby born to a mother with PROM4. HIV/Leishmaniasis co-infection5. HIV-AIDS associated opportunistic infections of the

respiratory system6. Post oesophagectomy patient developing fever on

3rd day post operative in ICU7. A patient with a history of mitral valve replacement

developing fever after 7 months of surgery.8. A paraplegic patient on long term indwelling

catheter9. Non healing foot ulcer in diabetic patient

1. Chronic diarrhoea in post transplanted patient

Causative agents•Bacterial-Mycobacterium avium-intercellulare complex•Viral- CMV•Parasitic-Cryptosporidium spp, Isospora belli,

Microsporidium, Strongyloides stercoralis

Immunosuppressive drugs 1. Suppress cell mediated immunity2. Suppress humoral immunity3. Anti inflammatory effect

ManagementCausative agent Diagnosis Treatment Prevention

M.Avium-Intracellulare

Blood culture Clarithromycin+ (ethambutol,rifabutin,ciprofloxacin)

Prevent aerosol tranmission

CMV Culture, PCR Gancyclovir, foscarnet (reactivation)

Cryptosporidim spp.

Stool concentration/ Modified acid fast stain for oocystsImmunofluorescence assay

Paromamycin,Nitosoxanide,Azithromycin (not practiced in SL)

Safe food and water, hygiene

Isospora belli Wet smear/Modified acid fast stain for oocysts

Albendazole,Mebendazole

Safe food and water, hygiene

Microsporidium stain the fecal sample with modified trichrome stain to detect spores ,Electron microscopy,immunoflurescence assay

Albendazole,Mebendazole

Safe food and water, hygiene

Strongyloides stercoralis

Rabditiform larva detection in stools

Ivermectin, Albendazole Proper sewage disposal, foot wear

1st option-reduce immunosuppressive drug regimen

2.Haemorrhagic Chicken Pox Aetiology - Varicella zoster virus

Potentially fatal disease

Affects immunocompromised individuals

Adults and children with

deficient cellular immunity

Leukemia, steroid therapy

and AIDS

Five major clinical syndromes Febrile purpura Malignant chicken pox Post infectious purpura Purpura fulminalis Anaphylactoid purpura

Diagnosis Tzanck smear - Cellular changes and EM Ag detection (Fluorescent antibody test) Culture and Ag detection DNA - PCR

Management Acyclovir treatment Adequate wound care Prevention

3.Sepsis in a baby born to a mother with PROM (preterm prelabor rupture of membrane)

Intact foetal membranes

Thickened mucus plug

Closed internl os

Antimicrobial properties of amniotic fluid

GBS,E coli, Listeria

DIAGNOSIS

Neonatal :- Blood culture , ESR / CRP , FBC

CSF examination

Maternal :- Vaginal swab, Amniotic fluid, Blood culture

MANAGEMENT

• Supportive therapy• Antibiotics

• Innate immunity- breach in the skin

• Adaptive immunity- breach in CMI

Breached defenses

• IV Drug abuse• Blood transfusion• Sexual transmission ?

Reasons for breach

• • CD4+ T cell loss T cell depletion

Mechanism of breach

n

• Further reduction in T cell count• Increase viral replication by parasites

AIDS

HIV Leishmaniasis

Co - infection

4.HIV/Leishmaniasis co-infection

•ELISA for Anti HIV Ab

•Western blot (serum)

•PCR – Viral RNA

•Microscopy (blood & BM)

•Immunochromotographic test

Diagnosis•Anti-

leishmanial drugs:

•HIV drugs : HAART

Management

•Prevention of IV drug abuse

•Safe blood transfusion

•Control of parasites

Prevention

For HIV

Amphotericin B Na antimony oral Miltefosine

For Leishmaniasis

5.HIV-AIDS associated opportunistic infections of the respiratory system.

Infectious Diseases Bacterial pneumonia,Pneumocystis jiroveci pneumonia,Other fungal

pneumonia,Mycobacterium tuberculosis need for prompt treatment.

History & Examination geographic location

Immunology CD4+ cell count

Laboratory Tests White blood cell count,

Serum lactate dehydrogenase,Arterial blood gas

Chest Radiograph/CT/MRI

Bronchoscopy

BACTERIALMYCOBACTERI

ALFUNGAL

VIRAL/

PARASITC

Streptococcus pneumoniae

Mycobacterium tuberculosis

Pneumocystis

jirovecii

Cytomegalovirs

Haemophilus species

Mycobacterium kansasii

Pseudomonas aeruginosa

Mycobacterium avium complex

Histoplasma

capsulatum 

Staphylococcus aureus

 Coccidioides immitis

 

Klebsiella pneumoniae

 

Aspergillus species

(esp. fumigatus

 

HIV-associated neoplasms or other disorders. Finally, HIV-infected persons may have preexisting pulmonary

disease (e.g., asthma), pulmonary disease unrelated to their HIV infection (e.g., pulmonary

embolism) may develop and be the cause of their symptoms.

Pulmonary Disease

Serology or Blood

Cultures

Sputum BALPleural

Fluid

Important

Other Sites

6.Post oesophagectomy patient developing fever on 3rd day post operative in ICU

Normal skin flora•Coagulase -ve staphylococcus•Candida•S. aureus including MRSA

skin

• damage to mucosa,•Flushing mechanism•Direct access tobladder

Gram –ve bacilli

Gram +ve cocci

S. aureusFungiViral

•E.coli•Candida spp.•Klebsiella•Pseudomonas spp.•Enterobacter spp.•Citerobacter•Proteus

Normal skin flora

•S. Aureus•C. Diphtheriae•Candida•Cryptococcus Gut flora•anerobes

Common organisms

Breech of defence

Common organisms

ET tube/ ventilators

Urinary catheter

CVP line

Cannula

Surgical incision site

Breech of defence

skin

•Mucociliary escalator,•reflux closure of glottis•CMI & HI

Specimens1. Blood for culture and ABST2. Urine for culture and ABST3. CVP line tip culture4. Sputum –if difficult to

obtain,transtrachial aspirate & bronchoscopic biopsy

5. Incision site pus for culture6. Drain fluid

Management1. Hx & clinical examination2. Fever chart maintanance3. Investigate for aetiological

agents & manage accordingly.

Wound infection – proper wound cleaning & proper antibiotics

UTI - remove catheter do not catheterised unless essential aseptic procedures antibiotic only on evidence of infectionRespiratory tract infection Proper antibiotic usage and

chest

physiotherapyCVP line and Cannula site infection

Prevention1. Aseptic surgical procedures2. Minimise drains,catheters &

IV lines post operatively3. Avoid pre-operative

antibiotics,4. Give peri operative AB s5. Minimize pre-op

hospitalization6. Eliminate nasal colonization

of S. Aureus

7.A patient with a history of mitral valve replacement developing fever after 7 months of surgery.

Suspicious case of Prosthetic Valve Endocarditis.

Bacterial endocarditis

Early (< than 60 days)• Staph aureus, Staph epidermidis

Late(>than 60 days)• Strep viridans 50%-70% (Streptococcus sanguis,

Strep.oralis & Strep. mitis) • Staph aureus 25%

Breached defenses.• Absence of blood

supply.• Abnormal blood flow.

WITH

Bacteremia.• Poor dental hygiene?• IV drug use?• Soft tissue infection?• Occult source?

Rare causes: HACEK Group & Culture negative BE

Diagnosis ?HistoryExamination > Splinter hemorrhages, Janeway lesions, Osler’s node, Roth

spots.Investigations >Blood culture, FBC, ESR, CRP, Liver biochemistry, ECG,

Echocardiography

Blood culture • Blood samples should be taken prior to antibiotic use.• At least 3 sets of samples ( 6 bottles)• Under aseptic condition. • Do NOT use cannula

Management• Start empirical antibiotic treatment• Change or continue antibiotics according to the patient’s response and

culture results.• Decision about surgical intervention should be made after joint

consultation between cardiologist and cardiothoracic surgeon.

Prevention• Use prophylactic antibiotics prior to dental & surgical procedures.• Good dental hygiene.• Avoid risky behaviors such as i.v. drug abuse.

Case Summary: Mrs. X, 71 year old paraplegic for 9 months on indwelling catheter presented with fever for 1 day with chills and burning sensation in urethra.Past medical history, DM for 5 yrs

Symptoms and signs: Fever, Chills, Burning sensation of Urethra & Pubic area, Nausea, Headache, Mild lower back pain

Problems; Catheter

Immunocompromised

Paraplegic and its complications

Female

Old age

MECHANISMS OF UTI…

• Mechanical trauma to urethra• Introducing normal flora• Bladder atonia - VU valve

incompetence •Diabetis: reduse immunity• Urine retention• Ascending infections

COMMON ORGANISMS…

# E.coli

# Klebsiella

# Proteus & Candida

PREVENTION AND MANAGEMENT…

Management…Predisposing factorsAntibiotics

Prevention…Avoid catheterisation Minimum durationIntermittent catheterisationAseptic conditionsClosed, sterile drainage systemMaintain gravity drainageProphylactic antibiotics

COLLECTION , STORAGE & TRANSPORTATION OF URINE SPECIMEN FOR LAB INVESTIGATIONS…

# UFR # Urine culture # FBC # Blood culture # ABST

Diagnosis - Catheter associated complicated UTI

NON HEALING FOOT ULCER IN DIABETIC PATIENTPathophysiology

Organisms involvedPolymicrobial cause- mostly involvedStaphylococcus aureusgroup A beta haemolytic StreptococcusStaphylococcus epidermidis Pseudomonas aeruginosagram negative anaerobes Candida spp.Gram negative aerobes Clostridium perfringensEnterococcus

Defense How it is compromised

Skin Trauma

Reflexes(pain) Loss of sensation due to diabetic neuropathy

Repair mechanisms Reduce blood supply by diabetic vasculopathy

Immunity Alteration of cellular and humoral immunity

Coordination Poor coordination due to reduced sensation ,poor vison ect.

MANAGEMENT Good diabetic control. Ulcer Mx - elevation, soft tissue support & antibiotics

with appropriate wound management. Ulceration with deep tissue invasion-rest, elevation, antibiotics for

secondary infection & protracted treatment with wound management. Mx of vascular insufficiency. ( Medical and Surgical ) If infection persists & leading to complication -amputation done

PREVENTION Good diabetes control Foot care Educating the patient.

Proper Hx & Ex

Laboratory testing- WBC count, ESR, glucose, etc...

Assessment of vascular insufficiency-peripheral pulses, Doppler U.S Bacterial cultures &

ABST-

Radiological testing- plain x-ray

DIAGNOSIS