Presentation on theme: "MANAGEMENT OF TB-HIV CO-INFECTION BY THE RESPIRATORY/INFECTIOUS DISEASE UNIT,UCTH, CALABAR."— Presentation transcript:
MANAGEMENT OF TB-HIV CO-INFECTION BY THE RESPIRATORY/INFECTIOUS DISEASE UNIT,UCTH, CALABAR
TUBERCULOSIS IN CHILDREN It is commonly asked why young children with tb are not infectious. – They generally have a closed infection – They do not have significant cough. – They lack tussive force necessary to suspend infectious particles in the air. – When cough is present children rarely produce sputum – When sputum is produced, organisms are sparse because they are in low concentration in the endobronchial secretions of children.
Diagnosis of TB in children- The Traditional Diagnostic prerequisites Combination of : Contact with infectious adult case Contact with infectious adult case Symptoms and signs Symptoms and signs Positive tuberculin skin test (TST) Positive tuberculin skin test (TST) Suspicious CXR Suspicious CXR Bacteriological confirmation Bacteriological confirmation Serology Serology
List of symptoms that may suggest TB in children: Fever (Low or high grade), not responding to anti- malaria treatment Weight loss, Static weight or failure to gain weight Failure to thrive Recent febrile illness with rash & desquamation (measles, persistent/continuous cough with vomiting (pertussis)
List of Suggestive Symptoms,continued Loss of appetite Lymph node swellings Angle deformity of the spine (back swelling) Joint or bone swellings Neck stiffness, vomiting, convulsions, impaired conscious (TB meningitis)
List of possible Physical signs Chronically or stmes acutely ill looking +/- pallor Small weight for the age (underweight), or features of PEM Discrete, or matted, frequently non-tender cervical lymphadenopathy Features of co-existing HIV or immunocompromised status Hypersensitivity parameters, eg Phlycternular conjuctivitis, Erythema Nodosum Manifestations of Primary Pulmonary Disease (primary complex, bronchial) Chest signs, or features of Extra-pulmonary TB.
TB Diagnosis in children & value of score charts In some countries, score charts are used for the diagnosis of TB in children but have rarely been evaluated or validated against a gold standard Marais BJ. Arch Dis child 2005;90:1166-70 Score charts also perform poorly in PTB and HIV infected children! Key features suggestive of TB The presence of 3 or more of the following should strongly suggest a diagnosis of TB: - Chronic symptoms suggestive of TB - Physical signs highly suggestive of TB - Positive TST - CXR suggestive of TB
Manifestations of TB in children >70% of children who develop TB disease have pulmonary manifestations, but ~25 – 35% may have an extrapulmonary presentation The most common extrapulmonary form is lymph node TB accounting for about 2/3 of cases of extrapulmonary TB 2nd most common form is meningeal disease occurring in 13% of patients
TB-HIV COINFECTION Manifestations of co-existent HIV-infection: – Persistent generalized lymphadenopathy, respiratory illnesses like pharyngotonsilitis, otitis media, mastoiditis, pneumonias, painless parotid enlargement. – Gastrointestinal conditions like oropharyngeal candidiasis, diarrhoea, vomiting
Other pointers of HIV infection: – Oral: Herpes simplex, oral thrush, oral hairy leucoplakia – Cutaneous: Chickenpox, molluscum contangiosum - Delayed developmental milestones – Severe progressive encephalopathy
History - Evaluation Careful history (including carefully extracting a history of TB contact) Symptoms: commonest: - Chronic cough > 21 days - Fever T > 38 o C for 14 days after excluding common causes, such as malaria or pneumonia - Wt loss or FTT Some children with TB infection may not develop any signs or symptoms at any time
Clinical features of HIV infection and associated conditions National Paediatric ART Training Slides Unit 4 13 Severe wasting Non-specific dermatitis
Dermatomal Herpes zoster Clinical features of HIV infection and associated conditions cont…. National Paediatric ART Training Slides Unit 4 17
Oral candidiasis Clinical features of HIV infection and associated conditions cont…. National Paediatric ART Training Slides Unit 4 15
Tuberculin Skin Testing (TST) TST is the method used for detecting whether an individual has come in contact with the TB bacilli. The TST used is the Mantoux test, containing 5 tuberculin units administered intradermally. The test is read as mm of induration at 48 to 72 hours.
Mantoux Test A positive test occurs when a person is infected with M. tb but does not necessarily indicate disease Interpretation: - 0 – 4mm = negative - 5 – 9mm = borderline - 10mm = positive in all other children irrespective of the BCG vaccination - 5mm = positive in HIV infected children and severely malnourished children (marasmus, kwashiorkor) Useful in screening household contacts with TB Fewer HIV infected children will have a positive TST TST may be negative initially but positive after 2-3 mo of treatment
Chest Radiograph as a diagnostic tool of TB Spectrum of radiolographic changes depends on the stage of the disease & the nature of the intrathoracic complications There are no pathognomonic radiological signs of tuberculosis; other lung lesions (viral, bacterial & fungal LIP & IPH) can mimic those of pulmonary TB. Additional radiographs like cervical, spinal/vertebral & abdominal may also be required
Chest Radiograph as a diagnostic tool of TB - 2 Certain radiological lesions may however suggest PTB: - Miliary mottling - Hilar or paratracheal lymphadenopathy - ± parenchymal involvement - Collapse consolidation - Pleural effusion Cavitatory lesions are rare, but should nevertheless be looked for, Rarely chest X-ray may be normal
Is this Miliary TB? No, its varicella pneumonia!
Bacteriological diagnosis in children Isolation of TB bacilli from clinical specimens remains the gold standard for diagnosis Isolation in children is more difficult than in adults, as they have paucibacillary disease The yield of the organism is low even in the best centres (<50%).
Specimen collection 1. Sputum : - 10 years or older who can expectorate an on the spot specimen, an early morning specimen and another on the spot specimen 2. Gastric aspiration (fasting, early morning) - Aspiration of gastric contents should be performed fasting, ideally while still recumbent after overnight sleep. - Therefore usually performed in hospitalized patients. - Strict adherence to the recommended collection techniques improves the yield of the procedure, as does the collection of specimens on three consecutive days.
Specimen collection-1 3. Induced sputum The use of nebulized hypertonic saline to induce coughing allows the production of respiratory specimens in children who cannot expectorate voluntarily Yield from 1 induced sputum specimen = 3 daily gastric aspirates, and is further by repeated procedures 149 children hospitalized pneumonia, Zar 2000 median age 9 (3-30) months IS in 142 (95%) Induced Sputum positive in 15(10.6%) vs 9 Gastric Lavage (6.3%), p=0.08
Specimen collection -2 4.Broncho-alveolar lavage 5.Fine needle aspiration (FNA): of enlarged glands for AFB and cytology – has a high bacteriological yield 6. Biopsy
Other diagnostic parameters FBC and ESR- may be normal but commonly leucocytosis with a relative lymphocytosis and a high ESR BCG test – Normal BCG evolution – Accelerated BCG reaction
Lipoarabinomannan (LAM) assay Antigen capture ELISA assays for the detection of lipoarabinomannan (LAM) in sputum and urine samples has shown promise in suspected TB adults (Boehme C et al, Trans Roy Soc Trop Med Hyg 2005;99:893-900) LAM is a cell wall lipopolysaccharide antigen specific for M. tuberculosis Released from metabolically active or degrading cells Secreted intact in urine Results are rapid, typically within 2-3 hours 76.5% sensitive in smear negative cases, 80.3% sensitive overall, 99% specific Performs well in the HIV-infected subgroup
Interferon Gamma Release assays (IGRA) New in-vitro test which measures interferon production by T-cells Principle: sensitised T cells produce interferon when mycobacterial Ags are encountered M. tuberculosis-specific Ags Available IGRA-based Tests: 1. Quantiferon-TB - IFN production (pg/ml) 2. T SPOT-TB - Detects number T cells producing IFN
TST vs IFN assays: traditional vs novel TST IFN Sensitivity75-90%* 80-95%* Specificity75-90% 95-100% Cross react BCGYesNo Cross react NTMYesNo BoostingYesNo CostLow Moderate Patient visits 21 Labnoyes * Less in the immunocompromised (Nahid, Proc Am Thorac Soc, 2006)
Concerns with IFN assays Cannot distinguish latent from active disease Few studies in children ? efficacy in very young/ HIV/ high incidence TB countries Discordance with TST results – Pai Lancet Infect Dis 2004, Mahomed IJTLD 2006 ? impact of TB treatment Need for laboratory Cost Promising and more sensitive than TST
Other Newer M. tuberculosis detection methods BACTEC offer slightly superior sensitivity and reduced turn around times compared with conventional Loweinstein – Jensen medium (LJ-medium) MODS( microscopic observation drug susceptibility assay) 8 days to culture positivity – limited utility in children PCR: limited utility in children and low sensitivity in paucibacillary TB NAAT (nucleic acid amplification test) rapid test (WHO endorsed): 100mins TB fluorescence microscopy Gene expert tb test
TB/HIV co-infection in children Should HIV testing be done in all children suspected of having TB (Yes) Should all HIV+ve children be screened for TB? (Yes) How do you differentiate HIV associated lung disease from TB disease? Can children with HIV lung disease also have TB disease? (Yes)
Anti-TB treatment: 2 phases Intensive phase - to rapidly eliminate majority of bacilli - to prevent emergence of drug resistance Continuation phase - to eradicate dormant organisms Either phase can be given daily or 3-times weekly.
Main objectives in TB Rx To rapidly kill most bacilli in order to: - stop disease progression - prevent transmission of infection To effect cure and prevent relapse (eliminate dormant bacilli) To do the above with minimal adverse reaction To prevent development of drug-resistant organisms
Desirable Characteristics of Drugs Bactericidal Good sterilizing activity Prevent of drug-resistance Low toxicity
1 st Line Anti-TB (Essential Drugs WHO) 1. Rifampicin 2. Pyrazinamide 3. Isoniazid 4. Ethambutol 5. Streptomycin
Codes for TB Rx regimens 2SHRZ/4H 3 R 3 Number in front of each phase = duration in months Letters = abbreviated drugs Subscript numbers following a letter = number of doses per week of that drug. If no subscript = drug is daily
Treatment: WHO category I New smear positive PTB New smear negative PTB with extensive parenchymal involvement Severe forms of extraPTB Severe concomitant HIV disease Treatment - 2HRZE, 4HR or 6HE TB Meningitis - 2HRZS, 4HR
Other Basic Principles Combination therapy - always Use fixed dose combination drugs if possible DOTS – directly observed therapy, short course Uninterrupted drug supply Children with severe forms of TB (meningitis, disseminated, TB spine, and TB pericarditis) should have streptomycin added during the intensive phase
Pharmacological challenges Rifampicin Decreases the plasma level of Nevirapine (37%), efavirenz (25%), not enough info on dosage adjustment in children. RMP can be used with EFV in children over 3years Decreases plasma level of all PIs Lopinavir(75%) ritonavir(35%) (LPV/r, Kaletra, Aluvia), Decreases plasma level of Zidovudine, abacavir
First line anti-TB drugs: Adverse effects DrugsAdverse events Isoniazid Skin rash, hepatotoxic, peripheral neuritis,psychosis Rifampicin Hepatoxic, red urine, anorexia, nausea, abdominal pain,thrombocytopenia, drug interactions Pyrazinamide Hepatotoxic, arthralgia Ethambutol Optic neuritis Streptomycin Rash, anaphylaxis, oto-and nephrotoxic
Drug-resistant Tb; Definitions Mono-drug resistance: Resistance to single drug Poly-drug resistance: Resistance to 2 or more drugs, but not to both INH and RMP MDR TB: Resistance to INH & RMP +/- other drugs XDR TB: MDR & 2 nd -line injectable & quinolone Primary resistance: No previous anti-TB Rx or less than 1 month Acquired resistance: Previous anti-TB Rx >1 month
Drugs resistant TB… (contd) WHO estimated that 511 000 new cases of MDR-TB occurred in 2007, 4.9% of all TB cases Contribution of Nigeria largely unknown Lately, Rifampicin mono-resistance seems on the increase in especially HIV-infected adults
Causes of Drug Resistant TB Poor management of drug-susceptible or mono-resistant TB cases e.g. incorrect regimens, interrupting treatment (drug supplies, poor bio- availibility), poor adherence by patients Poor management of MDR-TB cases leads to transmission of MDR-TB strains e.g. late diagnosis, not doing DST in relapse/retreatment cases, poor infection control measures especially in high prevalence HIV settings
MDR-TB in children Disease (>90%) in children usually develops within 12 months of infection This has to be confirmed with DST and DNA- fingerprinting Contact tracing and follow-up of children exposed to MDR/XDR-TB should receive high priority