Irritable Infant



  • Most children have some period of the day when they are most irritable, usually toward the evening:
    • Normal infant crying ranges from 3 hr/d at 6 wk of age and decreasing until 16 wk of age
    • During the first 6 mo of life, 1-mo olds have the highest prevalence of crying
  • Irritability is based on a comparison with the child's normal behavior pattern
  • Colic or excessive infant crying of unknown cause, is the most common cause of inconsolable crying in infants, occurring in as many as 25% of healthy children:
    • Episodes of paroxysmal screaming accompanied by drawing up knees and oftentimes passage of flatus
    • Usually begins at 2–3 wk and may continue through 12 wk, 3 hr/d
    • Diagnosis of exclusion


  • Bites: Spider/insect bite
  • Burn
  • Cardiac (supraventricular tachycardia, congestive heart failure, aberrant left coronary artery, coarctation of the aorta, endocarditis, myocarditis)
  • Child abuse
  • Corneal abrasion/foreign body (eyelash) in eye
  • Diaper pin
  • Diphtheria, pertussis, and tetanus (DPT) and other vaccine reactions
  • Endocrine/metabolic (inborn errors of metabolism, metabolic acidosis, hypernatremia, hypoglycemia, hypocalcemia, hyperthyroid – direct or by transplacental passage of maternal thyroid-stimulating immunoglobulins)
  • Foreign body, fracture, tourniquet (hair around digit or penis)
  • Gl (gastroenteritis, colic, gastroesophageal reflux, esophagitis, volvulus, malrotation constipation, cow's milk protein intolerance, anal fissure, intussusception, appendicitis)
  • Genitourinary (incarcerated hernia, testicular torsion, genital tourniquets, urinary retention) or localized
  • Infection: Systemic
  • Iron deficiency/anemia
  • Medications/toxins: Aspirin, antihistamines, atropine, adrenergics, home remedies, new prescription, mercury)
  • Meningitis
  • Minor acute infections (upper respiratory infection, otitis media, thrush, gingivostomatitis)
  • Neurologic (increased intracranial pressure: Mass, hydrocephalus, intracranial hemorrhage, hematoma – subdural, epidural, skull fracture)
  • Osteomyelitis
  • Parental anxiety
  • Pneumonia
  • Sickle cell crisis
  • Splinter
  • Teething
  • Trauma: Nonaccidental, SDH, fractures, shaken baby
  • UTI
  • Vascular

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