Dr Amdekar's Revision Notes Tuberculosis: An Unconquered Disease

Yeshwant K Amdekar, MD, DCH, FIAP* Consultant Pediatrician, Jaslok Hospital and Research Center and Breach Candy Hospital, Mumbai.

*Dr Amdekar is a practicing pediatrician for 50 years and a visiting consultant at SRCC Hospital, Mumbai. He has been a teaching faculty at the Institute of Child Health, Grant Medical College and JJ Group of Hospitals, Mumbai. He has also been the past President of Indian Academy of Pediatrics (IAP) and a member of editorial committee of Indian Pediatrics–the official journal of IAP

ABSTRACT: Robert Koch discovered TB bacillus more than 100 years ago and first anti-TB drug became available more than 60 years ago; but even then tuberculosis has remained unconquered in spite of the advances in diagnostic techniques and drug therapy. This is largely because of failure of rational diagnosis and non-standard therapy on the part of physicians and poor compliance on part of patients. This has resulted in increasing prevalence of MDRTB–multidrug resistant TB. HIV infection has added further threat to control of tuberculosis. Standard protocols for diagnosis are available and so also standard therapeutic regimes. It is the duty of every physician to follow these protocols strictly and ensure compliance on the part of patients.

Key words: childhood tuberculosis, TB diagnosis and therapy combination of clinical features has its drawbacks. Fever is often not documented and hence unreliable. Loss of appetite is non-specific and weight records are usually not available to confirm recent weight loss. In addition, a positive contact history is often not available. Besides, TB may present with variable degrees of fever and cough that may be different from the standard presentation. Such atypical presentations are fairly common and merit further discussion. Extrapulmonary TB is more difficult to suspect.

Tuberculosis (TB) is a chronic communicable disease that continues to be a major health problem in India. It is estimated that 5 in 1000 people are infected with Mycobacterium tuberculosis, of which half will present as smear positive. With such a high incidence of TB, it is not surprising that most children acquire the infection from adults in their surroundings. That is why the epidemiology of childhood TB follows that in adults. Consequently, early diagnosis and prompt standardized treatment of childhood TB is very important. Depending on the age at presentation, the symptoms and severity of TB vary, making diagnosis challenging. A proper understanding of the diagnosis and treatment of childhood TB by physicians is essential to limit the spread of the disease.

YK Amdekar

Standard Presentation Of Childhood Tb

Children can present with TB at any age, but the most common vulnerable age is between 1 and 4 years where serious forms of tuberculosis are more likely including TB meningitis and miliary TB. This is also an age where early diagnosis is a bigger challenge. Unexplained fever and/or cough for 2 weeks or more is highly suggestive of TB (Table 1) especially if it is accompanied by loss of appetite, weight loss and a positive contact history. In addition, failure to respond to broad-spectrum antibiotics and poor nutritional state make a diagnosis of TB even more likely. However, the

The Host Decides The Pathology And Therefore The Clinical Presentation Of Tb

Fever in childhood TB varies in acuity, severity and duration. Night fever accompanied by night sweats is typically seen in a malnourished child with an impaired immune response and the fever presents intermittently. An acute onset of high fever that lasts for a few days is a classical presentation in an older child with good nutrition and good immune function. An older child with localized destructive disease or a young child with military disease may present with moderately high continuous fever. Thus, the type of fever relates to the pathology and is suggestive of a particular type of TB.

Cough is an airway disease and depending upon the pathology, the severity of cough varies. A mild, dry cough is characteristic of TB as well as other kinds of upper airway disease. A severe cough suggests significant endobronchial lesion or airway compression by mediastinal lymph nodes. Cough with expectoration is classically seen in chronic cavitary lesions and bronchiectasis in older children. Thus, the severity of cough correlates with the pathology and one can suspect a

Table 1 – Algorithm for the diagnosis of childhood tuberculosis

abnormality on physical examination and should be suspected based on history as mentioned above. Fibrocaseous cavitary lesions on physical examination are quite pathognomonic of TB in India although they can be mimicked by fungal infection as well. Similarly, the acute onset of pleural effusion in a healthy older child is highly suggestive of TB in our epidemiology as are miliary lesions with hepatosplenomegaly.

Enlarged peripheral lymph nodes are often found in pulmonary TB in children and are useful clinical correlates to substantiate the diagnosis. However, insignificant cervical lymph nodes are so common and should not be considered in favor of TB. It is the size (often >1-1.5 cm), consistency (firm or matted) and progressive enlargement that suggests diseased lymph nodes.

Investigations

type of disease based on the cough. Other symptoms are very nonspecific and do not help a great deal in the diagnosis of TB. Recent weight loss is only significant if weight records are maintained. Thus, a growth chart is an excellent tool for monitoring general health and the presence of disease. In acute disease of any kind, body weight is lost but quickly regained when the body is back to normal. In contrast, in chronic disease, growth falters over weeks or months and serves as an early indicator of evolving disease even before symptoms develop. Childhood being a growing period, what better way to monitor a child’s health than by maintaining a growth chart! It is indicative of health and picks up early disease.

Physical Examination

Abnormalities in physical examination relate to pathology and not etiology. Thus, there are no classical clinical features of childhood TB. Pneumonia is characteristically the same irrespective of etiology, although chronic persistent pneumonia in spite of treatment with broadspectrum antibiotics raises the strong possibility of it being TB. Pulmonary primary complex is often devoid of any

The gold standard of diagnosis of TB is demonstration of acid-fast bacilli (AFB) in bronchial secretions, sputum or tissue obtained by biopsy such as a lymph node. It is now established that it is possible to confirm bacteriological diagnosis in childhood TB even in the early stage of the disease. Gastric aspirate collected early morning on an empty stomach on three consecutive days offers an easy way to demonstrate AFB. Older children may be able to produce a small sample of sputum for examination under the microscope. However, smears are often negative, as a higher number of bacilli are required to be present in a sample for positive detection. Standard