The Acutely Ill Infant (below 6 Months)

Essentials

• Examine infants without delay, before other patients, because particularly in infants younger than 3 months, there is a high risk of severe disease underlying acute symptoms. Particular vigilance should be exercised if the infant is less than 1 month old.
• Some significant congenital structural anomalies or diseases will not manifest immediately after birth but the symptoms may appear later.
• If the infant's general condition is poor, make an emergency referral for further management.
• Signs and symptoms are often difficult to interpret in infants, but an afebrile baby with appropriate muscle tone which eats well and shows satisfactory growth is rarely acutely ill.

Clinical examination

• Make a quick general assessment of the infant's condition. Start initial treatment immediately if the infant's colour (pale, grey, bluish), breathing (fast, laboured, lazy, interrupted) or reactions (feeble, slow, highly irritable, stiffening his/her muscles) are abnormal.
• A complete physical examination must always be carried out regardless of the reason for seeking medical help.
  • General condition and reactions (muscle tone, whining, sensitive to handling, painful, irritable, stiffening his/her muscles, lethargic, staring)
  • Breathing (fast, laboured, slow, interrupted, using auxiliary muscles; auscultation)
  • Circulation (heart rate, murmurs, temperature gradients and capillary refill, femoral pulses)
  • Skin colour (yellow, pale, grey, bluish), skin changes (rash, petechiae, blisters, bruising)
  • Fever, hypothermia
  • Palpation of the abdomen (distension, tenderness), bowel sounds, size of the liver and spleen, testicles and groins, and any hernias
  • Head and face, skull, suture lines, fontanelles
  • Mouth, pharynx, ears, eyes
  • Limbs
  • Primitive reflexes (Moro's reflex, stepping, grasping, sucking)
  • Weight compared to previous weight

Initial management

• If you judge that the infant is in poor general condition, treat immediately.
  • Support breathing and, if it is laboured or insufficient, start giving supplemental oxygen.
  • Establish IV access, and obtain blood cultures. If cannulation fails in an infant who is very ill, consider inserting an IO needle.
  • Give Ringer's solution in boluses of 10 ml/kg (up to 40-60 ml/kg) until circulation is stable, i.e., heart rate is 110-150/min and the periphery is warm.
  • Perform a blood glucose test. If the rapid blood glucose test gives a result of < 2.8 mmol/l, give 2-3 ml/kg of 10% glucose solution (G10) as an intravenous bolus.
  • Consider starting antimicrobial treatment if the distance to a hospital is long. Consult the receiving hospital, as necessary.

Fever (> 38.0°C)

• In as many as one in five cases, fever in an infant younger than 3 months is due to a bacterial infection. The risk of serious bacterial infection is particularly high in febrile infants younger than 1 month.
  • Febrile infants younger than 2 months always need to be assessed urgently by a doctor.
    • Febrile infants younger than 1 month should be sent directly to a hospital for taking blood and urine samples, blood culture, CSF sample and chest x-ray. There intravenous antimicrobial treatment is started, as well as aciclovir to cover any infection caused by Herpes simplex.
    • In infants of 1-2 months, choose investigations depending on their condition and findings.
  • A febrile infant of 2-3 months who is in good clinical condition can be examined the following morning.
• In infants older than 3 months, fever is mostly caused by viral infections, and investigations should be considered depending on their condition and the duration of symptoms (Table T1).
• See also Fever in a Child.

Respiratory distress

• Respiratory distress in an infant always requires emergency assessment. See also Difficulty Breathing in a Child.
• An infant should be admitted if
  • blood oxygen saturation is reduced
  • breathing is laboured
  • there are apnoeic episodes or
  • the infant's general condition or feeding are clearly affected.
  • In hospital, mucus can be removed by suction, supplemental oxygen can be given and breathing supported, as necessary. Sufficient nutrition is in most cases ensured by nasogastric tube feeding.
• In infants, respiratory distress is mostly associated with respiratory infections.
• Infants depend on nasal breathing. Nasopharyngeal stuffiness and secretions also affect eating.
  • At home, the infant's nose can be drained with a nasal aspirator; the most effective type is one that connects to a vacuum cleaner.
• Bronchiolitis is a respiratory tract infection usually caused by the respiratory syncytial virus (RSV), and occurring in epidemics.
  • The main signs are tachypnoea, overdistension of the chest due to air trapping, and intercostal and substernal retractions.
  • Expiratory wheezing and inspiratory crepitations may be present.
• Pneumonia may be caused by either bacteria or viruses.
  • More important than trying to distinguish between an upper and lower respiratory tract infection is to identify and treat any respiratory distress.
  • CRP, blood count, any viral samples and a chest x-ray will help to decide whether or not antimicrobial treatment is needed.
• Infants younger than 6 months very rarely have obstructive expiratory difficulty typical for older children and treatable with bronchodilators.
• Heart failure is a rare cause of respiratory distress. See Symptoms of cardiac origin.
• There are also other rare causes of abnormal breathing in infants, such as metabolic and neurological disorders, diseases of the lungs or internal organs, serious intestinal problems and haematological crises.

Cough

• A respiratory tract infection is often associated with a cough. A typical cough associated with viral infection does not require treatment..
• Whooping cough should be suspected if coughing occurs in intense bouts affecting breathing.
  • Suspicion of whooping cough Whooping Cough in an unvaccinated infant younger than 3 months is sufficient to warrant hospitalisation and initiation of treatment with a macrolide.
  • An infant with whooping cough will show very few symptoms between bouts of coughing.

Central nervous system symptoms

• Acute central nervous system (CNS) symptoms in an infant younger than 6 months require emergency assessment at a hospital.
  • Developmental delay or regression without an acute change in the infant's condition can be investigated on an outpatient basis.
• Lethargy or floppiness or abnormal reactions are signs of severe disease that may be due to a problem other than a primarily neurological one.
• Convulsions in an infant, even if they have already passed, always require emergency assessment.
  • Convulsions may be caused not only by infections but also by electrolyte disturbances or other metabolic problems, cerebral circulatory disturbances, such as obstruction or haemorrhage, and CNS anomalies.
  • Blood glucose must be measured in all infants with convulsions or vague symptoms.
• Convulsions of CNS origin cannot be stopped by touching.
• It is important to recognize infantile spasms, because starting treatment early will improve the prognosis.
  • Infantile spasms typically consist of series of episodes of the limbs and trunk stiffening into flexion or extension for about 1 second.
  • Such series of spasms are usually mild at first, gradually becoming more severe.
  • At first, the only symptom may be stopping movement for a moment.
  • Episodic symptoms should be videoed, if possible.
  • Development will halt or regress.
  • The typical age at onset of symptoms is 4-7 months.
• Harmless muscle twitching during sleep (sleep myoclonus) is common in infants. Such twitching only occurs during sleep and always stops when the infant wakes up.
• Fever convulsions do not typically occur in infants younger than 6 months.
  • Fever with CNS symptoms suggests a CNS infection.
  • Nuchal rigidity is a rare sign in infants with meningitis Meningitis in Children, but the fontanelle may be bulging.
• In many cases of shaken baby syndrome there are no externally visible signs. The possibility of child abuse should be borne in mind Suspected Child Abuse: Identification and Actions, and the infant should, if required, be referred to specialized care as an emergency case.
• If an infant has convulsions, the airway must be kept open and adequate oxygenation ensured (oxygen saturation > 92%).
  • A prolonged convulsive tonic-clonic seizure in an infant over 3 months should be treated with buccal midazolam (0.20-0.25 mg/kg) or rectal diazepam (0.5 mg/kg) Acute Care of Seizures of Cerebral Origin in Children. Prepare for respiratory support after administering the medication.

Symptoms of cardiac origin

• Even though maternity hospitals screen neonates for congenital heart defects before discharge, a significant share of critical heart defects are only diagnosed after discharge.
  • In defects where the systemic or pulmonary circulation depends on the arterial duct, the infant's condition will usually get drastically worse within the first week of life, as the arterial duct closes.
  • In defects with profuse blood flow through a shunt from systemic to pulmonary circulation, heart failure will typically get worse during the first weeks or months of life, as pulmonary resistance decreases.
• A murmur may be heard but is not present in all heart defects.
• In aortic coarctation, femoral pulses are missing or weak.
• Tachypnoea or increased respiratory workload may be symptoms of heart failure.
• If the pulse rate is high (over 200), suspect supraventricular tachycardia (SVT).
  • During an episode of SVT, narrow complex tachycardia is typically seen that is even and does not vary in response to soothing, for example.

• If a heart defect associated with the arterial duct is suspected in an infant, specialized care should be consulted immediately.
• If symptoms that have developed more slowly are suspected of having a cardiac cause, in primary health care careful clinical examination is essential.
  • If possible, blood pressure in all limbs (normally higher in lower than in upper limbs) and oxygen saturation should be measured.
  • If arrhythmia is suspected, an ECG should be performed.
  • If a heart defect is suspected based on these, additional investigations can be performed in specialized care as considered indicated: chest x-ray (cardiomegaly, pulmonary vascular congestion), ECG (arrhythmias, conduction disturbances), blood pressure from each limb and blood count (possible anaemia). Echocardiography can be performed, as necessary.

Acute intestinal symptoms

• Regurgitation of even large volumes of milk is common.
• If the infant is well, its weight is increasing well and the stomach is soft, there is no need to suspect any underlying disease.

Jaundice

• See also Jaundice in the Newborn.
• Infants with jaundice should be examined as an emergency case if their general condition is affected. Jaundice in an unwell infant may be due to dehydration, infection, haemolysis or metabolic disturbances.
• If jaundice in a neonate who is well continues for more than 2 weeks, biliary atresia destroying bile ducts out- and inside the liver should be excluded.
  • The symptoms include light, clay-coloured stools, in addition to jaundice.
  • Bilirubin and conjugated bilirubin should be tested.
    • If the level of conjugated bilirubin exceeds 20 µmol/l or 20% of total bilirubin, the infant must be referred for further investigations.
  • Early diagnosis and surgical treatment will improve the prognosis.
  • The patient will feel well at first, and diagnosis should be made before they start feeling worse.
• Breast milk jaundice is a benign cause of prolonged jaundice. Jaundice associated with breast feeding need not be treated, and breast feeding should not be interrupted.