HIV Flashcards
What is the risk of developing TB in HIV?
26-31x higher in HIV population hence why if TB+ve should always check HIV status
In the UK when assessing patients with HIV for LTBI what test do you do ?
IGRA
If first result indeterminate/borderline then repeat within 4 weeks, if remains indeterminate then clinician discretion
What is the treatment regimen for drug sensitive TB in HIV positive patients ?
Standard TB therapy
Where antiretroviral therapy necessitates the use of Ritonavir boosted protease inhibitor what change to medication is required ?
Rifampicin is replaced by Rifabutin
In HIV patients with Isoniazid Resistant TB, what is the drug regimen?
Rifampicin, Pyrazinamide, Ethambutol, Levofloxacin
What is the timing in which ART is given to newly diagnosed HIV , TB positive patients?
All newly diagnosed HIV patients with TB , irrespective of their CD4 count are offered ART as soon as practical within 4 weeks of diagnosis .
If CD4 count <50 should be within 2 weeks
If CNS TB , delay initiation of ART for 8 weeks
What is the ART regimen usually started for those taking Rifampicin based anti-TB meds ?
Efavirenz (Raltegravir/ Dolutegravir)
+
Tenofovir Deproxil
+
Emtricitabine
Do individuals who develop TB on ART with undetectable viral loads need any changes to ART?
No , continue same regimen
(NB if needing Ritonavir boosted PI then switch Rifampicin to Rifibutin ; avoid Combicistat with Rifampicin/Rifabutin )
What is Immune Reconstitution Inflammatory Syndrome in TB with HIV?
Paradoxical worsening of disease (worsening fever , CXR infiltrates, increased lymphadenopathy or new manifestations of the disease) at the initiation of HIV treatment . Represent restoration of the pathogen specific immune responses , steroids reduce morbidity associated with IRIS
Outline differences seen in HIV and TB co-infection
In HIV and TB co-infection clinical and radiological presentation of TB may be atypical compared with immunocompetent and more likely to have a normal CXR and be smear negative but culture positive
What is the gene that confers resistance to Rifampicin?
rPoB
Why do patients with HIV get chest infections?
The immune dysregulation associated with HIV results in an increased risk of respiratory infections at all CD4 counts. Widespread use of prophylaxis has reduced risk of life threatening infection but not returned to background levels of negative HIV population
Most common is PCP and bacterial pneumonia
What increases a patients risk of opportunistic infections (OI) in HIV?
- Patients use of OI prophylaxis
- Recent dx from hospital or current IP >5 days
- Country of residence /travel
- Hx of active lung disease
- Level of host immunity
- Neutropaenia
- Prolonged cause of immune modulation (steroids)
What is Pneumocystis Jirovecii?
Fungus
Who gets PCP?
90% of cases are in HIV seropositive patients with CD4 counts <200
Other predictive factors:
- non adherence to prophylaxis
- oral candidiasis
- oral hairy leukoplakia
- unintentional WL
- recurrent bacterial pneumonia
- previous PCP
- high HIV viral load
How does PCP present ?
Exertional dyspnoea progressing over several weeks with malaise and dry cough , inability to take a deep breath in and fever often apparent
Exam often normal (can have end inspiratory crackles) , spontaneous or infection associated PTX should prompt exclusion of PCP
What does the radiology demonstrate in PCP?
Perihilar haze , interstitial infiltrates (characteristically sparing the apices and costophrenic angles) pneumoatocoeles and pneumothorax but can have normal CXR
Radiology not sensitive/specific for dx
How do you diagnose PCP?
Induced sputum (sensitivity 50-90%)
BAL
(Open lung biopsy- if not improving and prev no result)
** spontaneously expectorated sputum is not adequate alveolar sample and should not be processed**
Remember Pneumocytis Jitovecii cannot be cultured in vitro and diagnosis relies on visualization of the organism (Histochemical - silver stain such as Gregory Gimori or immunofluoro) OR NAAT
** do not delay treatment for the procedure as samples will remain positive 7-10 / 7 into treatment
What is the treatment for moderate/severe PCP (PaO2 <9.3 or sats <92%)
High dose IV Co-Trimoxazole and IV/PO steroids, can be switched
IV Co-Trimoxazole 120mg/kg/day TDS/QDS for 3/7 and then 90mg/kg/day TDS/QDS for 18/7
Prednisolone 40mg BD for 1-5 days , then 40mg OD for 6-10 days, then 20mg OD for 11-21 days (if can’t take oral can have IV methylpred at 75% of the dose)
When are corticosteroids of benefit in PCP?
PaO2 < 9.3 or sats <92%
if started within 72 hours of specific anti PCP therapy
If treatment failure or not tolerated what are the options?
Clindamycin and Primaquine
Or
Pentamidine
What is the treatment for mild PCP?
1920mg TDS or 90mg/kg/day TDS septrin
What is association between G6PD and PCP?
Haemolysis can be triggered by oxidant drugs (including Primaquine , Dapsone and Sulfamethoxazole) need to check patients G6PD status but shouldn’t delay treatment
If G6PD positive and PCP positive what do we give?
Pentamidine or Atorvaquone
What is the prognosis of PCP?
Survival approaches 90%
Early CPAP can be beneficial , avoid mechanical ventilation
Who gets PCP prophylaxis and what is it?
HIV with CD4 <200 or a CD4 % of all lymphocytes <14%
Co-Trimoxazole 960mg x3 per week or OD, or 480mg OD
If individuals have CD4 > 200 for more than 3 months , can discontinue prophylaxis
Is early initiation of HAART favoured in individuals with PCP?
Yes
What are the risk factors for HIV related pneuomnia?
Declining CD4 count
Injecting drugs
Cigarette smoking
Occurs at all levels of immunosuppression
Recurrent pneumonia x2 in 12 months is AIDs defining
What are the bacteria found in HIV related pneumonia?
S.Pneumoniae and H.Influenzae predominate
S.Aureus increasing
P.Aeurginosa more common at low CD4 counts
As with non HIV patients, those who develop pneumonia in hospital , gram negative must be considered very likely
How do we treat HIV seropositive individuals with CAP?
As per guidelines for non HIV positive patients
Do HIV seropositive patients get prophylaxis for pneumonia ? Does HAART help?
Abx prophylaxis not recommended
23 Pneumococcal subtype vaccine recommended
HAART helps but less impactful than opportunistic
How does pulmonary infection with Cryptococcus Neoformans present ?
Can be indistinguishable from PCP, fever, cough , exertional dyspnoea and pleuritic chest pain
What does CXR demonstrate with pulmonary Cryptococcus Neoformans in HIV patients ?
Solitary nodules, consolidation, interstitial infiltrates, cavitation , lymphadenopathy or pleural effusion. Can get pneumothoraces
Diffuse interstitial infiltrates most common with advanced immunosuppression or coinfection
NB : disseminated disease is most common at presentation
How do you diagnose Cryptococcus Neoformans?
Culture of the yeast with or without positive antigen or staining of yeast on BAL /pleural fluid
Induced Sputum
BAL
Pleural fluid
> > GIEMSA STAIN , INDIA INK STAIN (reveals encapsulated yeast) or by Calcofluor white with fluorescence microscopy)
> > Cryptococcal antigen can be detected in BAL (sens 100% , spec 98%)
If cyrptococcal positive what other ix needed in HIV patient ?
Examination of CSF, so LP
How do you treat cryptococcosis?
Amphotericin B and Flucytosine and then stepped down to fluconazole
If isolated pulmonary , no hypoxia and -Ve CSF then Fluconazole 400mg OD for 10 weeks
Who gets invasive aspergillosis ?
Aspergillus colonises the lung, particularly in individuals with underlying lung disease. Invasive aspergillosis is when the fungus invades the parenchyma and disseminates to other organs (may occur in HIV +ve)
Patients who have : Neutropaenia , transplantation, glucocorticoids
How does aspergillosis present?
Fever, cough , SOB (insidious)
Tracheobronchitis - rare - ulcerative or nodular lesions in the airway (often Neutropaenia / steroids also) - fever, cough , dyspnoea, wheeze , stridor
How do we diagnose aspergillosis in HIV patients ?
Compatible clinical syndrome and biopsy demonstrating Aspergillus by culture or histology
OR
Consistent clinical and radiological appearance with positive micro for sputum or BAL
What are the specific fungal stains for aspergillus?
KOH on sputum /BAL
grocott gomori stain
NB Galactomannan enzyme linked immunosorbant assay that detects the presence of cell wall constituent of Aspergillus (IV taco con can give false +ve)
How do we treat aspergillosis in HIV patients ?
Voriconazole
6mg/kg BD for 24 hours
4mg/kg BD for 7 days
200mg BD for 12 weeks
Alternatives :
Posiconazole
Amphotericin B is main alternative
IF SIGNIFICANT HEPATIC /RENAL IMPAIRMENT:
Caspofungin
Do HIV patients get prophylaxis for Aspergillosis ?
No
Does CMV in urine /blood/BAL indicate infection?
No , not without evidence of end organ involvement. CMV establishes latency and individuals with low cell mediated immunity can develop severe disease due to reactivation .
However reactivation is common in those with advanced immunosuppression and frequently does not cause end organ damage
What are the symptoms of CMV pneumonitis?
Dry cough, exertional SOB and fever with marked hypoxaemia
What does the imaging show in CMV pneumonitis ?
Marker bilateral interstitial infiltrates or ground glass attenuation but unilateral alveolar consolidation, bilateral nodular opacities, pleural effusion, rarely cavitates
How to diagnose CMV pneumonitis ?
BAL/Biopsy + Compatible clinical syndrome + No alternative dx
NB if suspected should have an eye exam for CMV retinitis
Remember CMV replication in respiratory tract is frequently only a marker of immunosuppression and not pneumonia
How do you treat CMV pneumonitis ?
Gangciclovir 5mg/kg BD IV for 21 days
Foscarnet / Cidofovir are alternatives
If looking for oral can have Valganciclovir 900mg BD PO
Do we give prophylaxis for CMV in HIV patients ?
Valganciclovir is given as primary prophylaxis in patients with persistent immunosuppression and detectable CMV DNA or as secondary prophylaxis in those with relapse of CMV pneumonia
Do HIV patients have increased influenza compared with general population?
No but increased severity of disease
How diagnose influenza?
NPA/ Nasal swab
How do you treat influenza in HIV patients ?
Oseltamivir - neuraminidase inhibitor
(Alternative Zanamivir - useful for IV /resistance)
Give if flu positive and fever >38 for <48 hours
Also recommended to receive doxycycline or Co-Amoxiclav and Clari for 7/7
Who gets prophylaxis for influenza in HIV population?
CD4 <200
No vaccination
Exposed in last 48 hours
All patients encouraged to get annual flu vaccine
