INFECTIOUS DISEASES III.pptx

INFECTIOUS DISEASES III CHILDHOOD TUBERCULOSIS DR UGOLEE JERRY INTRODUCTION •Tuberculosis is a chronic inflammatory disease caused by Mycobacterium tuberculosis. •It is characterized by delayed hypersensitivity, tissue destruction and attempts at healing. •It commonly affects the lungs and is mos...

INFECTIOUS DISEASES III CHILDHOOD TUBERCULOSIS DR UGOLEE JERRY INTRODUCTION •Tuberculosis is a chronic inflammatory disease caused by Mycobacterium tuberculosis. •It is characterized by delayed hypersensitivity, tissue destruction and attempts at healing. •It commonly affects the lungs and is most communicable in this form. •It may also affect almost any organ system, including the lymph nodes, CNS, liver, bones, skin, genitourinary and gastrointestinal tract. EPIDEMIOLOGY •Worldwide prevalence of TB in children is difficult to say •It is a leading cause of morbidity and mortality especially in developing countries •8 – 10 million people develop tuberculosis annually worldwide of which over 3 million of these are in subSaharan Africa •The incidence of TB has greatly increased with pandemic of HIV/AIDS in sub-Saharan Africa •More than 33% OF HIV infected children may develop TB EPIDEMIOLOGY •Globally: •1,600,000 people died from TB in 2017, 300,00 of this no were PLHIV •1,000,000 children were infected with Tb in 2014 •400 children die daily from TB •Nigeria: •According to 2012 survey, incidence is 338/100,000 •6th among 30 high burden countries (TB, TB/HIV, DR-TB) •1ST in Africa •Only 15% of estimated TB cases are notified •Difficult to diagnose TB in children AETIOLOGY Aetiology •Mycobacterium tuberculosis complex: •M. tuberculosis, M. bovis, M. africanus, M. microti  Transmission • Airborne via inhalation of the released TB bacilli Importance source is contact with an untreated adult PTB case Cough, spitting or sneezing tiny droplet nuclei with organism Primary infection in children often follow prolonged contact with an untreated adult with cavitorary disease • Ingestion of unpasteurized milk transmit M. bovis from infected cattle Transmission by airborne droplets Natural History of TB Risk factors • • • • • • • • Age below 5yrs or above 14 years Contact with an adult with chronic cough Birth in an endemic country / IDP camps Malnutrition/ Poverty HIV infection Measles/ Pertusis infection DM Other immunosuppressive conditions Common sites of TB disease • • • • • • • • Lungs Pleura Abdomen Central Nervous System Lymph nodes Genitourinary systems Bones and joints Disseminated (military TB) Wallgreen Timetable • • • • • • PTB Few months Miliary and meningeal TB 2-6 months TB adenitis 3-9 months Bones and joints Several years Renal and genital TB >10 yrs Reactivation TB -years after primary infection CLINICAL FEATURES • Depends largely on the site of infection, constitutional symptoms and signs include Weight loss, Anorexia, Night sweats, generalized lymphadenopathy and fever • Other more specific clinical findings may include • Cough • Pleuritic chest pain • Haemoptysis • Gibbus • Neck swelling • Abdominal distension, abdominal pain & ascites PULMONARY TB • Commonest form of TB occurring alone(90%) or in combination with other forms in more than 70% of cases • In children, it usually arises from an extension of the ghon focus or the whole complex and diagnosis may be missed easily as mode of presentation can be vague • Upper lungs lobes are more frequently affected than lower lobes likely due to better blood supply and aeration or poor lymph drainage PULMONARY TB Common symptomatology include • Cough x 3weeks ( some say 2weeks) • Fever (low grade, continuous) • Anorexia • Weight loss or poor weight gain • Night sweats • Pleuritic chest pain • Haemoptysis ( following pul artery erosion ) PULMONARY TB • • • • • • • • Common signs on respiratory system examination Dyspnoea Tachypnoea. Dull percussion notes, ↑ tactile fremitus Localized wheezing (enlarged hilar lymph nodes) Decreased breath sounds Rales Bronchial breath sounds (cavitation's) Egophony PTB ( Hilar adenopathy) Primary PTB (Hilar adenopathy) “doughnut sign” TB SPINE( POTT’S Dx) • Also known as tuberculosis spondylitis, rare but commonest TB bone disease in children • May follow lymphatic spread from adjacent areas, commonly the lungs or haematogenous spread from primary focus • Lower thoracic vertebrae is the most often affected site, followed by lumbar, then upper thoracic and then sacral (uncommonly) TB SPINE( POTT’S Dx) • The infection can spread between adjacent vertebrae into adjoining disc space causing caseous necrosis and collapse • Spread of infection from lumbar vertebrae to psoas muscle causing abscesses is not uncommon • X-ray findings include lytic destruction of anterior vertebral body with increased anterior wedging with collapse of vertebral body and loss of intervertebral disk space • Clinical findings include a gibbus, reduced power in the lower limbs and brisk reflexes TB Spine TB ADENITIS • Most common form of extra pulmonary TB infection. A chronic granulomatous inflammation of the lymph nodes with caseation necrosis forming a tuberculous granuloma often close to the collar bone • The lymphadenites progresses to a periadenitis then forms a cold abscess(collar stud abscess) and may then form a sinus • Treatment commonly dose not require surgical draining of the abscess just anti-TB medication TB ABDOMEN • Extra pulmonary TB involving abdominal organs such as intestines, peritoneum, liver or abdominal lymph nodes. May occur in isolation or alongside PTB or part of disseminated tuberculosis • Accounts for about 5% of global tuberculosis with gastrointestinal TB been the most common and the ileocecal junction the most involved region possibly due to its abundance of lymphoid tissue TB ABDOMEN •Other form include peritoneal TB, TB of the mesenteric and omental nodes, hepatic and renal TB •Spread most commonly is haematogenous •Signs and symptoms depend on the site of involvement and may include abdominal pain, abdominal distension, ascites, nausea, constipation, diarrhoea, blood in stool and intestinal obstruction •Surgical intervention may be required in complicated cases with gut perforation, abscess, fistulas or obstruction TB OF THE CNS • May occur as TB meningitis or a tuberculoma. DIAGNOSIS • Diagnosis begins with good taking and a detailed physical examination with a heighted index of suspicion as TB symptoms may be vague • Specific investigations include -FBC ESR, Mantoux, Sputum AFB/ Gastric washings/aspirate for AFB microscopy, Chest Xray(PTB), biopsy and histology for TB adenitis, Abdominal USS for Abdominal TB, LP /CT/MRI for TB meningitis and tuberculomas • Others are TB gold test, Gene xpert(sputum or stool), PCR and culture of specimens( sputum/gastric washings or pleural fluid) using Lowenstein Johnson media(6wks) or MGIT liquid agar(14days) Mantoux Reaction DIAGNOSIS MANTOUX TEST Interpretation • 0 –4mm = negative • 5 –9mm = borderline • ≥ 10mm = positive irrespective of BCG vaccination status • ≥ 5mm = positive in HIV infected children and severely malnourished children (marasmus, kwashiorkor) A positive test occurs when a person is infected with M. TB but does not necessarily indicate active disease AFB MICROSCOPY L J MEDIUM MGIT MEDIUM Gene Xpert (now 1st line, detects MTB, ready in 2 hours) TREATMENT • Treatment involves case finding and diagnosis and the use of anti-tuberculous medication using the WHO outline ‘directly observed tuberculosis treatment’ control strategy program (DOTS), where health workers or a motivated caregiver directly enforces compliance with drug regimen by directly observing patients swallow their medication • There are multiple possible drug regimens, some countries use 6 months and others 8month regimen • This improves adherence, saves cost and lowers the risk of drug resistance developing TREATMENT • The Mainstay of treatment is combination chemotherapy • Treatment is divided into 2 phases -Intensive phase – 2 months -Continuation phase – 4 months/10months • Anti-TB drugs are isoniazid(INH), rifampicin(RIF), ethambutol(EMB), pyrazinamide(PZA) and streptomycim • Isoniazide and rifampicin are more specific to M. tuberculosis and are used in the continuous phase • Steroids like prednisolone maybe used as adjuncts TREATMENT • Intensive phase(1ST 2months): • Tabs Isoniazid 10mg/kg/day,Cap rifampicin 15mg/kg/day,Tab pyrazinamide 30mg/kg/day, tabs Ethambutol 15mg/kg/day, Streptomycin 20mg/kg/day. • Continuation phase(4-8months), isoniazid and rifampicin • Corticosteroids reduce inflammation cerebral oedema and possible adhesions. • Tab prednisolones 1mg/kg/day for 4wks and then tapered over 2-4weeks. TREATMENT Indications for steroid therapy in TB • TB meningitis • TB pericarditis • TB pleural effusion • TB laryngitis • Endobronchial TB • Severe hypersensitivity reaction associated with TB and to anti-TB drugs • Renal tract TB • Massive lymph node enlargement with pressure effect TREATMENT Common side effects of 1st line anti-TB drugs Rifampicin • Orange discoloration of urine and tears • Gastrointestinal disturbance • Hepatotoxicity • Thrombocytopenia Isoniazid • Peripheral neuritis • Hepatotoxicity • Psychosis TREATMENT Common side effects of 1st line anti-TB drugs Pyrazinamide • Hyperuricaemia • Skin rash • Hepatotoxicity Ethambutol • Optic neuritis • Hepatotoxicity • Streptomycin- ototoxicity & nephrotoxicity PREVENTION • Case-finding and effective treatment • Contact tracing and INH chemoprophylaxis • BCG vaccination • Improvement in the general standard of living