tuberculosis in children i
DESCRIPTION
paediatrics lecture notes on tuberculosis from college of medicine, university of ibadan, NigeriaTRANSCRIPT
Tuberculosis in Children
By Professor K. Osinusi
TUBERCULOSIS
An important infectious disease globally
About 30% of the world’s population are infected by
the organism that causes tuberculosis
8 to 10 million people develop the disease annually
About 3 million of them are in sub-Saharan Africa
CAUSES OF RESURGENCE IN INCIDENCE OF TB:
Worsening economic situations
Multidrug resistance
HIV pandemic
Decline of national tuberculosis control programmes
Large number of displaced persons living in poor conditions
as a result of conflicts and wars
EPIDEMIOLOGY (I)
Aetiological agent mycobacterium tuberculosis and mycobacterium bovis mycobacterium africanus
Characteristics of mycobacteria
It multiples slowly
It is resistant to many anti- microbial drugs
It remains viable in macrophages by subverting macrophages-killing
Its waxy coat together with its many components substances depress immune
responses against it.
EPIDEMIOLOGY (II)
Sources of Infections: Most important source is sputum of persons with open tuberculosisMode of Spread: Inhalation Ingestion Penetration of skin and mucous membranePredisposing Factors: Age Sex Malnutrition Intercurrent infection Overcrowding & poor living conditions
Pathophysiology
Tuberculosis is a chronic inflammatory disease i.e inflammation of prolonged duration in which active inflammation, tissue destruction and attempt at repair proceed simultaneously
The tubercle bacilli being of low toxicity evokes an immune response called delayed hypersensitivity reaction.
Granulomatous inflammation is a specific type of chronic inflammation which occurs in TB
A focal area of granulomatous inflammation is known as granuloma
In tuberculosis the granuloma is referred to as a tubercle which is classically characterized by the presence of central area of caseous neurosis.
PRIMARY INFECTIONS
Primary focus ) + ) Primary Complex
regional lymph nodes )Primary Focus- Size – varies from a few millimeter to 2 centimeter in diameter- Site – usually situated in the sub-pleural region- Symptoms & signs
May be symptomless May be associated with minor symptoms like malaise and anorexia May be associated with muco-cutaneous manifestations ie erythema
nodosum and phlycternular conjunctivitis
- Primary complex can heal or progress into active disease- Risk of primary infection developing into an active disease is about
15% in the first ten years after infection
Ways in which primary infection can progress to active disease
1. Primary focus can spread to contiguous part of the lungs giving rise to tuberculous pneumonia.
2. Primary focus and the regional lymph nodes may merge and give rise to an area of consolidation.
3. Extensive caseation and liquefaction can develop giving rise to cavity formation.4. The inflamed nodes may compress the neighbouring bronchi giving rise to atelectasis
or emphysema.5. Node may erode through the bronchial wall causing endobronchial tuberculosis.6. There may be discharge of the tubercle bacilli into the lumen leading to bronchogenic
dissemination to other areas of the lungs.7. Nodes may erode into the blood vessels giving rise to haematogenous spread to other
tissue.8. The affected nodes may develop fibrosis and encapsulation with viable tubercule
bacilli persisting within the node for many years and may be the source of reactivation tuberculosis.
Period between primary and the appearance of clinical evidence of various forms of TB
Pulmonary tuberculosis – within a few months of primary infection.
Miliary and meningeal tuberculosis – 2-6 months.
TB adenitis - 3-9 months.
Bones and joints – several years.
Renal and genital tuberculosis – may take over a decade.
Pulmonary lesions occurring as a result of reactivation of a dormant
tuberculosis focus previously established in the body takes a number of years
after primary infection.
PULMONARY TUBERCULOSIS
Commonest form of tuberculosis – occurring alone or in combination with other
forms in 70% of cases.
Pulmonary tuberculosis in children consists mainly of primary complex and direct
progression of its component.
Pathological findings include:
* Hilar enlargement which may lead to bronchial compression with resulting
hyperinflation or atelectasis.
* Consolidation – patchy or lobar with or without pneumothorax and pleural effusion.
* Cavitation.
Clinical Features
Early symptoms are usually vagueChronic coughFeverAnorexiaWeight lossFailure to gain weightHaemoptysis
Signs:- Dyspnoea- Tachypnoea- Localized wheezing- Decreased breath sounds- Crepitations- Bronchial breath sounds- Chest examination may reveal no abnormality- Clinical features of reactivation tb in older children are similar to those of the primary infection but
cough is usually productive and there may be chest pain.
DIAGNOSIS
History Detailed history of current illness Past medical history Family and social history History of contact
INVESTIGATIONS1. Tuberculin skin test2. Chest radiograph Hilar adenopathy Parenchymal lesions
- Patchy infiltrates- Consolidations- Atelectasis- Pleural effusion- Cavities
3. Bacteriological investigations- Sputum ) staining- Gastric washings ) and culture
4. ESR5. FBC
Differential Diagnosis
Pneumonia- Bacterial- Viral- Mycoplasma
Lung abscess Bronchiectasis Pulmonary fungal infections Pulmonary neoplasm
PLEURAL EFFUSION
TB pleural effusion occurs when:
- Sub pleural primary focus ruptures into the pleural cavity.- A caseous node ruptures into the pleural cavity.- During haematogenous spread.- As a result of allergic response to tuberculo-protein.
Clinical Features:Symptoms: Fever
Weight lossChest pain on deep inspiration
Signs: Dullness to percussionDiminished or absent breath sounds.
PLEURAL FLUID:
- Sero-Fibrinous, sometimes blood-stained
- Protein 2-4 g/dL
- High white cell count with predominance of lymphocytes
- Culture yields tubercle bacilli in less than 20%.
MILIARY TUBERCULOSIS
Most severe form of disseminated TB.
Clinical Manifestations:- Variable, depending on the load of organism, organs affected and immune status of the
child.- Onset of symptoms may be explosive or insiduous.Symptoms: Fever
AnorexiaWeight lossCoughWheezing
Signs: Generalised lymphadenopathy.Hepato-splenomegaly.Respiratory distresssigns of meningitis or peritonitis present in 20-40% of cases.Choroidal tubercles.
INVESTIGATIONS
Tuberculin skin testCXRCSF tapHistological examination of
Lymph nodeLiver biopsyMarrow biopsy
Diff. Diagnosis of miliary picture on CXR
- Sarcoidosis- Eosinophilic pneumonia- Pulmonary fungal infection- Chicken-pox pneumonia- Childhood histiocytosis syndrome
TUBERCULOSIS OF THE CNS
Comprises:- Tuberculous meningitis- Tuberculoma
Tuberculous meningitis- Occurs about 2-6 months after the primary infection
- Most common in children aged 6 months to 4 years
- Arises as a result of haematogenous spread of tubercule bacilli to the cerebral cortex and meninges.
Clinical Manifestation
Can be divided into 3 stagesStage I:
Non-specific symptoms like:FeverHeadacheweight lossIrritabilityDrowsiness
Stage II
- Lethargy- Nuchal rigidity- Seizures- Positive Kernig’s sign- Vomiting- Stigns of brainstem involvement- Cranial nerve palsies- + other focal neurological signs
Stage III
- Hemiplegia or paraplegia- Coma- Decrebrate rigidity- Opisthotonus- Fundoscopy may show papilloedema and choroidal
tubercles.
INVESTIGATIONS
1. Tuberculin skin test2. CXR3. Examination of CSF
CSF Picture:May be straw-coloured or may be clear and colourless- WBC 10-500cells/cmm with predominance of lymphocytes
Protein may be over 1GM/dl- Glucose – Low, less than 40mg/dl- Staining with ZN stain may yield Afb- Culture may be positive
PROGNOSIS
Depends on the stage of disease at commencement of therapy.Stage I - Prognosis goodStage III -Mortality is high and a high percentage of those who survive have complications like: - blindness
- deafness- paraplegia- mental retardation- speech disturbance- cranial nerve palsies- Hydrocephalus
TUBERCULOMA
- Presents as an intracranial space-occupying lesion- Usually infratentorial- May be single or multiple
CLINICAL MANIFESTATIONHeadacheFeverConvulsionLateralizing signsInvestigations- Tuberculin skin test- Skull X-ray- CXR- CT Scan of the brain shows discrete masses with surrounding oedema
Diagnosis is often made at surgical exploration for intracranial tumour.