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Fever and Infections of Infancy and Childhood Delane Shingadia, Senior Lecturer in Paediatric Infectious Diseases Objectives What causes fever How to measure of body temperature Signs and symptoms of infection in children Diagnosis, investigation and management of febrile child Fever of unknown origin Use of antipyretics and antibiotics What is Fever? Temperature Regulation Humans are homeothermic (body temperature maintained within narrow limits) Thermostat that modulates heat production and heat loss to maintain core temperature within narrow limits Stability of core temperature Thermoregulatory Centre in the Brain Hypothalamic thermostat Heat gain and loss Too hot. Too cold Changes in External Temperature What causes fever? Fever is a centrally regulated rise in body temperature in response to a pathologic stimulus Set point is raised and therefore equilibrium is upset Caused by ‘endogenous pyrogens’ or products of the inflammatory cell response Pyrogens and fever But remember that not all fevers are due to infections (endogenous pyrogens) Malignancy e.g. leukaemia Inflammatory diseases e.g. rheumatoid arthritis Unknown Mercury Thermometers Most accurate Measurement of Body Temperature Take 2-4 minutes to read Core temperature Risk of breakage and mercury ingestion rectal thermometer Mouth, rectum or armpit 0.5 ºC above oral and 1-1.5ºC above axillary Most accurate Electronic Thermometers Oral temperature (mouth) Quicker to read (30 secs) Axillary temperature (armpit) Reasonably accurate when used by someone with experience Ear temperature May underestimate core temperature Forehead temperature Infrared Ear thermometers Relative size of body shell Popular Less accurate Skin Temperature measurements Estimate temperature of tympanic membrane Temperature-sensitive crystals Inaccurate because they only estimate skin temp and not core temp Fever in Children Lower limit of 38.0°C (rectal) However serious and life-threatening infections can occur with normal to low temperatures Young infants/ neonates may be hypothermic with infection Causes of Fever in Children Bacterial infection Fungal infection Viral infection Parasitic infection Common Causes of Infection in Childhood Bacteria Virology Gram Positive bacteria RSV Staphylococcus aureus Varicella Streptococcus pneumoniae Rotavirus Gram Negative bacteria Adenovirus Bordetella pertussis Enterovirus Haemophilus influenza Herpesvirus Neisseria meningitidis Parvovirus Salmonella spp. Fever in children 65% of children <2 years will visit a physician for an acute febrile illness 19-30% of encounters in clinical practice Most commonly caused by self-limited viral illness and localized bacterial infection, but may be presenting feature of something more serious infection e.g. meningitis Diagnosis of Febrile Visits History How many days of fever? More History How high was fever? Anyone else sick in the family? Any other symptoms? Contact with animals? Cough/runny nose/difficulty in breathing Any history of travel? Irritability/fits Past medical history Diarrhoea/vomiting Family history Pain on passing urine Drug history Tugging at ears Limping/not weight-bearing Skin rash Examination Does child look well or unwell? Ear, nose, and throat Respiratory system Cardiovascular system including measurement of pulse and blood pressure Abdominal system for palpable liver or spleen Skin examination for rash Bones and joints for swelling, redness or pain Central nervous system including neck stiffness, irritability or full fontanelle Newborns and children <1 year age May have nonspecific symptoms such as poor feeding or lethargy May have minimal symptoms and signs May not have fever (may be hypothermic) May fall ill rapidly Fever in Children – different clinical spectrum Fever with source or clinical signs Common infections Rash Lymphadenopathy Hepatosplenomegaly Toxic appearing child or septic shock Fever without source Fever of unknown origin Common Causes of Fever in Children Ear infections (otitis media) Throat/upper respiratory tract infections (pharyngitis, tonsilitis, laryngitis) Meningitis Lower respiratory tract infections (pneumonia/empyema) Abdominal infections (gastroenteritis) Urinary tract infections Skin infections (cellulitis/impetigo) Bone and joint infections (arthritis/septic arthritis) Ear Infections Two year old boy with left ear pain Fever with lymphadenopathy Infections Cellulitis Viral (HIV, EBV, CMV) 14 year old boy with left eye swelling and fever Tuberculosis Toxoplasmosis Meningitis Connective tissue disorders (JRA, SLE) Neoplasm (leukaemia, lymphoma) Tonsillitis Drug reaction (phenytoin) Six year old girl with difficulty swallowing Miscellaneous (sarcoidosis, histiocytosis) Urinary Tract Infections Infectious Mononucleosis 9 month old girl with fever and poor feeding 13 year old boy with lymphadenopathy Pneumonia Pictures of infectious mononucleosis 10 year old boy with fever, cough and difficulty in breathing Fever with hepatosplenomegaly Osteomyelitis Infectious 4 year old not weight-bearing and limping for 3 days Epstein-Barr virus Cytomegalovirus Fever and Rash Toxoplasmosis Parvovirus infection (slapped cheek) Human immunodeficiency virus (HIV) Hepatitis viruses Viral Exanthems Tuberculosis Measles Catscratch disease Chickenpox Noninfectious Haematological malignancy Kawasaki Disease Connective tissue disorders Unusual Cause of Fever and Rash Swollen knee of a youth with Lyme arthritis ‘Toxic Appearance’ or septic shock Bacteria in blood stream release toxins that cause blood vessels to dilate and leak Clinical picture consistent with the sepsis syndrome Lethargy/sleepy Cold and poorly perfused extremities Low blood pressure/rapid pulse Hyperventilation cyanosis Spectrum of Septic Shock Severe sepsis (altered organ perfusion) Septic shock (hypotension and poor capillary refill) Multiorgan dysfunction syndrome (coagulopathy, respiratory distress, renal failure, hepatobiliary dysfunction and neurological dysfunction Neisseria meningitidis Meningitis/Septicaemia Fever without a source Acute febrile illness in which the aetiology of the fever is not apparent after a careful history and examination Accounts for 14% of children with fever May be difficult to differentiate children with viral infection versus occult bacteraemia Fever of unknown origin Fever for at least 7 days Negative history, examination and laboratory testing Cause Infectious 40-50% Collagen-vascular 10-20% Neoplasms 5-10% Undiagnosed 20-30% Infectious causes of FUO Systemic viral infections (EBV, CMV) Urinary tract infection Tuberculosis Bacterial endocarditis Brucellosis Cat scratch disease Abdominal abscess Rarer causes Prolonged Fever Initial Investigations Full blood count and differential white cell count (neutrophils, lymphocytes) C-reactive protein Bacterial blood culture Urine microscopy and bacterial culture Chest x-ray Throat swab/ nasopharyngeal aspirate Lumbar puncture for cell count and bacterial culture Treatment of Fever External cooling Tepid sponge or bath Paracetamol (acetaminophen) Anti-pyretic only Very safe except with overdose Aspirin and ibuprofen (non-steroidal anti-inflammatory drugs) Antipyretic and anti-inflammatory Inhibit prostaglandin synthesis Side effects (gastritis, bleeding, bronchospasm) When to use anti-pyretics? Patient uncomfortable because of fever Risk of febrile convulsions Risk of clinical deterioration Critically ill children High risk for cardiac or respiratory decompensation Very high fevers >40°C When to use antibiotics? Very ill child with severe disease example septic shock Suspected focal bacterial infection e.g pneumonia, meningitis Very young babies/infants (usually <1 year old) with fever but no focus Immunosuppressed children with fever e.g. HIV, leukaemia Child with petechiael rash Fever in Children: conclusion Many bacterial and viral causes of fever in children Need to obtain a good history and thorough examination to determine nature of infection Younger infants may not have obvious signs or symptoms but may be at risk of more serious infections Fever control with antipyretics may be necessary in some children Empiric antibiotics may be needed in those at high risk of serious infection or who are clinically unwell, especially shock The end product ded in those at high risk of serious infection or who are clinically unwell, especially shock The end product
"Fever and Infections of Infancy and Childhood"