Clinical Manifestations of Tuberculosis in Children

Introduction

Tuberculosis (TB) in children is often referred to as "the great imitator" because of its protean manifestations. Unlike adults, where the disease is predominantly pulmonary and confined to the lungs (reactivation), pediatric TB is largely a primary disease characterized by lymphohematogenous spread. The clinical presentation depends heavily on the age of the child, immune status, and the time elapsed since the primary infection.

Wallgren’s Timetable of Tuberculosis

Understanding the natural history helps in anticipating clinical manifestations:

1. Incubation (3–8 weeks): Development of tuberculin hypersensitivity; usually asymptomatic or mild fever.
2. Miliary/Meningeal TB (2–6 months): Early dissemination; acute and life-threatening.
3. Pleural Effusion (3–9 months): Allergic response.
4. Skeletal TB (1–3 years): Bone and joint involvement.
5. Renal TB (>5 years): Late reactivation.

1. Systemic (Constitutional) Symptoms

Systemic symptoms are common to both pulmonary and extrapulmonary forms but are often nonspecific, leading to delayed diagnosis.

• Fever: Usually low-grade, irregular, or appearing in the evening. In miliary TB, it may be high and spiking,.
• Failure to Thrive (FTT): Significant weight loss (>5% in 3 months) or failure to gain weight despite adequate nutrition is a hallmark of pediatric TB. In infants, this may be the only presenting sign.
• Anorexia and Malaise: Generalized fatigue, reduced playfulness, and loss of appetite,.
• Night Sweats: Less common in young children than in adults/adolescents,.

2. Pulmonary Tuberculosis (PTB)

The lung is the portal of entry in >98% of cases. Pediatric PTB differs significantly from adult-type disease.

A. Primary Pulmonary Complex (Asymptomatic)

The "Primary Complex" or Ghon Complex consists of a subpleural parenchymal focus (Ghon focus), lymphangitis, and regional lymphadenopathy.

• Clinical Picture: The vast majority of immunocompetent children are asymptomatic or have a transient flu-like illness that resolves unrecognized.
• Signs: Physical examination is usually normal.
• Diagnosis: Often incidental finding of a positive Tuberculin Skin Test (TST) or hilar adenopathy on Chest X-ray (CXR) done for contact screening,.

B. Symptomatic Primary Pulmonary Disease

Symptoms arise when the host immune response fails to contain the primary complex.

• Cough: The most common symptom. It is usually non-productive, persistent (>2 weeks), and does not improve with standard antibiotics.
• Dyspnea: Mild tachypnea or shortness of breath may be present.
• Physical Signs: Surprisingly meager compared to radiological findings. There may be decreased breath sounds or mild crackles.

C. Complicated Primary Disease (Lymph Node-Bronchial TB)

This is the most common form of symptomatic PTB in infants and young children due to the compression of soft, pliable airways by enlarged hilar/paratracheal lymph nodes.

• Airway Compression:
  • Partial Obstruction: Leads to ball-valve emphysema (hyperinflation) of the distal segment. Clinical features include localized wheezing (monophonic) and decreased air entry.
  • Complete Obstruction: Leads to collapse (atelectasis). The classic radiographic finding is "Collapse-Consolidation" (Segmental lesion),.
• Endobronchial TB: The lymph node may erode into the bronchus, discharging caseous material. This causes severe cough, respiratory distress, and sometimes expulsion of caseous plugs.
• Mediastinal Syndrome: Rarely, massive adenopathy compresses the esophagus (dysphagia) or Superior Vena Cava (SVC syndrome).

D. Progressive Primary Disease (PPD)

Occurs when the primary focus enlarges and undergoes liquefaction instead of calcification.

• Presentation: Resembles acute bacterial pneumonia with high fever, toxicity, and productive cough,.
• Cavitation: Rare in infants (primary cavity) but severe when it occurs.
• Course: Without treatment, it may lead to miliary spread or extensive lung destruction.

E. Reactivation (Adult-Type) TB

Seen in children >7 years, particularly adolescents,.

• Pathology: Apical infiltration and cavitation due to high oxygen tension favoring bacillary growth.
• Symptoms: Productive cough, hemoptysis (rare in young children), chest pain, fever, and night sweats.
• Infectiousness: These adolescents are often sputum smear-positive and highly infectious, unlike young children.

F. Pleural Tuberculosis

Common in older children (5–15 years), rare in infants. It represents a hypersensitivity reaction to tubercular protein.

• Onset: Can be acute (mimicking pneumococcal pneumonia) or insidious.
• Symptoms: High fever, pleuritic chest pain (worse on inspiration), and breathlessness.
• Signs: Stony dullness on percussion, decreased breath sounds, and mediastinal shift to the opposite side,.

3. Extrapulmonary Tuberculosis (EPTB)

EPTB is more common in children (20–30%) than adults due to efficient lymphohematogenous dissemination.

A. Tuberculous Lymphadenitis (Scrofula)

The most common form of EPTB (approx. 70%),.

• Sites: Anterior cervical (jugular), submandibular, and supraclavicular nodes are most frequently affected. Axillary/inguinal nodes may be involved secondary to BCG or extremity lesions.
• Characteristics:
  • Onset: Insidious, enlarging over weeks/months.
  • Palpation: Initially firm, discrete, non-tender, and mobile.
  • Progression: Nodes become matted (fixed to each other) and fixed to the overlying skin.
  • Cold Abscess: Caseation leads to softening (fluctuance) without acute signs of inflammation (redness/warmth), hence termed "cold abscess".
  • Sinus Formation: Rupture leads to a chronic non-healing sinus tract (collar stud abscess).

B. Central Nervous System (CNS) Tuberculosis

The most severe form, carrying high mortality and morbidity.

1. Tuberculous Meningitis (TBM) Occurs usually within 6 months of primary infection. The clinical course is classically divided into three stages,:

• Stage I (Prodromal - 1 to 2 weeks):
  • Nonspecific symptoms: Low-grade fever, anorexia, irritability, apathy, stagnation of weight gain, and loss of developmental milestones.
  • No neurological deficits.
• Stage II (Meningitic/Transitional):
  • Abrupt onset of neurological signs.
  • Signs of meningeal irritation (nuchal rigidity, Kernig’s/Brudzinski’s signs).
  • Raised Intracranial Pressure (ICP): Vomiting, headache, bulging fontanelle.
  • Cranial Nerve Palsies: Commonly VI (Abducens), III, and VII nerves due to basal exudates.
  • Seizures and drowsiness.
• Stage III (Paralytic/Coma):
  • Deep coma/stupor.
  • Decerebrate or decorticate posturing.
  • Dense hemiplegia/paraplegia.
  • Irregular vital signs (Cushing's triad).

2. Tuberculoma A granulomatous mass presenting as an intracranial space-occupying lesion (ICSOL).

• Location: Often infratentorial (brainstem/cerebellum) in children,.
• Symptoms: Headache, vomiting, seizures (focal or generalized), and focal neurological deficits without signs of meningitis.

C. Abdominal Tuberculosis

Can involve the bowel, peritoneum, or lymph nodes.

• Intestinal TB: Commonly affects the ileocecal region. Presents with colicky abdominal pain, alternating diarrhea and constipation, and a palpable mass in the right iliac fossa.
• Peritoneal TB:
  • Wet type: Ascites (exudative).
  • Dry/Plastic type: Doughy abdomen (due to matted omentum and intestines),.
• Nodal TB: Enlarged, necrotic mesenteric lymph nodes, often palpable as masses.
• Systemic: Fever, weight loss, and anorexia are prominent.

D. Disseminated (Miliary) Tuberculosis

Result of massive lymphohematogenous dissemination. Common in infants and immunocompromised children.

• Clinical Features:
  • Onset: Can be insidious or explosive (acute sepsis-like).
  • Symptoms: High spiking fever, wasting, dyspnea, and cough.
  • Signs: Generalized lymphadenopathy, significant hepatosplenomegaly, and fine crepitations on auscultation (often absent despite extensive radiological disease).
  • Pathognomonic Sign: Choroidal tubercles on fundus examination (yellowish/white nodules on the retina) seen in up to 50% of cases,.
  • Skin: Papulonecrotic tuberculids (rare).

E. Skeletal Tuberculosis (Bone and Joint TB)

Occurs 1–3 years after primary infection.

• Spinal TB (Pott’s Spine): Accounts for 50% of bone TB.
  • Affects thoracic > lumbar vertebrae.
  • Symptoms: Back pain, stiffness, refusal to walk/bend.
  • Signs: Localized tenderness, Gibbus deformity (kyphosis due to vertebral collapse), and cold abscess (paravertebral/psoas).
  • Complication: Pott’s paraplegia due to cord compression.
• TB Arthritis: Monoarticular involvement of weight-bearing joints (hip, knee). Presents with pain, swelling, limp, and muscle wasting.
• TB Dactylitis (Spina Ventosa): Painless cystic expansion of fingers/toes in young children.

F. Other Forms

• Pericardial TB: Fever, distant heart sounds, friction rub, signs of cardiac tamponade.
• Renal TB: Sterile pyuria, hematuria, dysuria (rare in children, usually >10 years latency).
• Cutaneous TB: Lupus vulgaris (apple-jelly nodules), Scrofuloderma (breakdown of underlying node), TB verrucosa cutis (warty lesion).

4. Congenital and Perinatal Tuberculosis

Rare but fatal if untreated.

• Transmission: Transplacental (hematogenous to liver) or aspiration of infected amniotic fluid.
• Presentation:
  • Onset in 2nd–3rd week of life.
  • Sepsis-like picture: Respiratory distress, fever, lethargy, poor feeding.
  • Hepatosplenomegaly (prominent in transplacental spread).
  • Obstructive jaundice and lymphadenopathy,.

5. TB and HIV Co-infection

• Presentation: TB is more aggressive and progresses rapidly.
• Features: Higher rates of extrapulmonary and disseminated disease.
• Diagnostic Challenge: TST is often negative (anergy). Classic cavitary disease is less common; interstitial infiltrates are common,.

Summary of Key Clinical Pearls

1. Age Matters: Infants get miliary/meningeal TB; adolescents get cavitary pulmonary TB.
2. Symptoms: Persistent fever and weight loss are the most consistent systemic signs.
3. Signs: Lung findings are often disproportionately fewer than radiological findings.
4. Lymph Nodes: Matted, non-tender cervical nodes suggest TB.
5. Neurology: Basal meningitis with cranial nerve palsies is classic for TBM.
6. Eye: Choroid tubercles are a specific clue for miliary TB.