Child Abuse — Physical and Sexual

• Traumatic brain injury and non-accidental head trauma (NAHT): Abusive head trauma results from violent shaking and impact, generating shear forces that tear bridging veins and cause subdural hematomas (most common intracranial injury in abuse). The immature brain is particularly vulnerable due to increased head-to-body ratio, larger subarachnoid spaces, and incomplete myelination. Repetitive acceleration-deceleration forces cause axonal injury at the gray-white matter junction, leading to diffuse axonal injury (DAI). Retinal hemorrhages occur from increased intrathoracic pressure and venous congestion during violent shaking. Secondary ischemic injury develops through hypoxia, hypercapnia, and elevated intracranial pressure from cerebral edema, perpetuating neuronal death hours to days after initial trauma.

• Bone fractures and remodeling response: Metaphyseal fractures ("corner fractures" or "bucket-handle" fractures) represent pathognomonic abuse injuries resulting from violent twisting or pulling of limbs. These occur at the weakest point—the metaphyseal zone of hypertrophic chondrocytes—where immature bone matrix provides minimal resistance to shear stress. Rib fractures (particularly posterior) indicate severe compressive force and high specificity for abuse in children <3 years; they result from direct compression of the chest wall during violent gripping or impact. Spiral fractures of long bones occur from rotational trauma. The immature periosteum is loosely attached, allowing hematoma formation between bone and periosteum, producing characteristic radiographic findings ("corner sign," "metaphyseal lucencies"). Subperiosteal new bone formation occurs during healing as the periosteum attempts calcification of organizing hematoma.

• Abusive sexual contact mechanism: Sexual abuse involves mucosal trauma, inflammation, and disruption of normal epithelial barriers. Sexually transmitted infections (STIs) develop through direct inoculation of pathogens (Neisseria gonorrhoeae, Chlamydia trachomatis, Treponema pallidum, HSV, HPV) onto genital and oral mucosa. The inflammatory response generates suppuration, bleeding, and tissue destruction. In prepubertal children, the lack of estrogen results in thin, atrophic vaginal epithelium with increased fragility. Anal fissures and tears occur from forced penetration, with subsequent scarring and stricture formation. Anogenital injuries trigger immune responses with local infiltration of lymphocytes and neutrophils, producing edema, erythema, and friability. Psychological sequelae—including dysregulation of the hypothalamic-pituitary-adrenal (HPA) axis—result from chronic trauma exposure, with elevated cortisol, altered stress reactivity, and lasting neurobiological changes in limbic structures.

• Neglect and failure to thrive mechanism: Chronic neglect produces protein-calorie malnutrition with depletion of visceral proteins (albumin, prealbumin), resulting in decreased oncotic pressure, edema, and impaired immune function. Growth hormone and insulin-like growth factor-1 (IGF-1) levels decline with inadequate nutrition, disrupting linear growth. Micronutrient deficiencies (iron, zinc, folate, vitamin D) impair hematopoiesis, immune development, and bone mineralization. Emotional neglect alters attachment and causes disruption of early brain development, particularly in the prefrontal cortex and amygdala, predisposing to behavioral dysregulation and psychiatric illness.

• Pattern injury mechanisms: Immersion burns from forced submersion produce sharp demarcation between burned and spared skin (absence of splash marks), indicating intentional placement. Contact burns from cigarettes, grills, or implements show reproducible geometric patterns. Bruising patterns reflecting implement use (loop marks from cords, grab marks, hand prints) indicate direct impact with recognizable objects.

• Parental substance abuse and intoxication: Alcohol and drug use impair parental judgment, impulse control, and emotional regulation. Intoxicated caregivers have decreased capacity to respond appropriately to infant crying or child misbehavior, escalating violence. Methamphetamine use associates with extreme aggression and psychosis. Substance abuse also indicates increased likelihood of chaotic home environment, untreated psychiatric illness, and reduced supervision.

• Parental mental illness (depression, personality disorders, psychosis): Untreated maternal depression reduces capacity for emotional attunement and increases irritability. Antisocial personality disorder and narcissistic traits associate with lack of empathy and increased aggressive responses to perceived slights. Parental psychosis can manifest as bizarre, severe abuse motivated by delusional thinking.

• Social isolation and lack of community support: Families lacking extended family contact, religious community, or social services are at dramatically increased risk. Single parenting combined with poverty, limited childcare resources, and geographic isolation removes natural safeguards. The absence of additional adults to provide respite or intervene perpetuates cycles.

• Prior history of abuse (intergenerational transmission): Adults with childhood abuse history have 6-fold increased risk of perpetrating abuse, though importantly, most abuse survivors do not become abusers. Unresolved trauma, insecure attachment styles, and normalized violence increase risk.

• Child vulnerability factors: Infants and toddlers (peak incidence <3 years) are at highest risk due to complete dependence, crying that triggers frustration, and inability to report abuse. Children with special needs (developmental delay, physical disability, behavioral problems) experience higher abuse rates due to caregiver stress and reduced capacity for self-protection.

• Domestic violence in the household: Intimate partner violence strongly predicts child abuse, with shared risk factors and overlap in 30-60% of cases. Children exposed to domestic violence experience direct harm and heightened trauma.

• Poverty and economic stress: Financial strain, food insecurity, and housing instability create environmental stress and reduce access to mental health and social services. Poverty itself is not causal but represents a risk marker for these confluence of factors.

• Parental lack of knowledge about child development: Caregivers with unrealistic developmental expectations (e.g., expecting a 6-month-old to toilet train) may respond with violence to normal behavior.

Physical Abuse

• Unexplained bruising in patterns: Loop marks, grab marks (5 fingertip bruises on buttocks or extremities), hand prints, implement marks (cigarettes, cords, utensils), and clustering of bruises in various healing stages suggest intentional injury. Bruising in a non-ambulatory infant or in the TEN-4 zone (Torso, Ears, Neck, and any mark in children <4 years) has high specificity for abuse. Normal childhood bruising typically appears over bony prominences (shins, knees, elbows) in ambulatory children.

• Abusive head trauma (AHT) with altered mental status: Acute presentation includes lethargy, irritability, vomiting, seizures, respiratory depression, and coma. Initial injury may be subtle with nonspecific symptoms (poor feeding, fussiness) followed by deterioration. Retinal hemorrhages (usually bilateral, extensive, extending to periphery) are present in 50-90% of NAHT cases and are highly specific for abusive injury. Fundoscopic examination is therefore essential.

• Fractures unexplained by mechanism of injury: Metaphyseal fractures are virtually pathognomonic for abuse in infants. Posterior rib fractures detected on skeletal survey indicate severe compressive force inconsistent with accidental falls. Multiple fractures in different healing stages ("dating" fractures by radiographic appearance shows progressive callus formation) indicate repeated trauma over weeks to months. Sternal fractures, scapular fractures, and vertebral compression fractures are extremely rare in accidental trauma in young children.

• Visceral injuries (abdominal/thoracic trauma): Blunt abdominal trauma without clear mechanism may cause pancreatic injuries (elevated lipase, amylase), liver lacerations (elevated transaminases), splenic rupture (rapid decompensation), or bowel perforation (free air on imaging). Chest trauma may produce hemothorax, pneumothorax, or pulmonary contusions.

• Burn injuries with characteristic patterns: Immersion burns show sharp demarcation without splash marks, stocking-glove distribution, or uniform depth, indicating forced submersion in hot water. Contact burns reproduce the shape of heating element (cigarette burns are small, circular, with defined borders and no surrounding erythema; grid pattern from grills; linear marks from heating elements). Absence of splash marks or absence of grab marks in a child pulled from hot water suggests forced immersion rather than accidental scalding.

Sexual Abuse

• Anogenital injuries and findings: Acute lacerations or bruising of labia, hymen, fossa navicularis, or anal verge indicate recent penetrating trauma. Hymenal scarring, cleft hymen, transection, or extensive friability suggest previous abuse. Anal fissures, anal scarring, and anal strictures indicate previous penetrative abuse. Importantly, absence of physical findings does not exclude sexual abuse; 70% of sexually abused children have normal/nonspecific genital exams.

• Sexually transmitted infections: Confirmed diagnosis of gonorrhea, chlamydia, syphilis, or HSV in a prepubertal child is abuse-indicative (vertical transmission in infants excluded). HPV and Mycoplasma genitalium are concerning for sexual abuse in children >3 years.

• Behavioral and emotional manifestations: Age-inappropriate sexual knowledge or behavior, acting out of sexual scenarios with dolls or peers, sexual aggression, and excessive masturbation are concerning for sexual abuse. Regressive behavior (bedwetting, thumb-sucking in older children), anxiety, depression, PTSD, school refusal, and behavioral acting out frequently follow disclosure or recognition of abuse.

• Pregnancy and sexually transmitted disease in adolescents: Pregnancy in girls <15 years or discordance between reported partner age and sexual history warrants abuse investigation. STIs in adolescents, though sometimes consensual, must be assessed for coercion or age-of-consent violations.

• Disclosure statements: Children may disclose abuse to trusted adults; these statements require careful documentation verbatim, as therapeutic interviewing and contamination of narrative can affect legal proceedings.

Neglect

• Severe malnutrition and failure to thrive: Weight and height <5th percentile with developmental delay, muscle wasting, loss of subcutaneous fat, prominent ribs, and distended abdomen (from protein malnutrition and hepatomegaly) indicate chronic inadequate nutrition. Edema may paradoxically be present due to low albumin.

• Severe diaper dermatitis and skin infections: Lack of basic hygiene produces severe diaper rash with maceration, secondary bacterial/fungal infections, and skin breakdown. Scabies, lice, and severe impetigo indicate neglectful care.

• Untreated medical conditions: Severe cavitary dental disease, unmanaged chronic illness (diabetes, asthma without medications), severe vision/hearing impairment without correction, and developmental delay without intervention indicate medical neglect.

• Unsafe living environment: Hazardous substances accessible to children, lack of heat/utilities, animal feces, mold, lead paint hazards, and unsecured weapons create immediate danger.

Clinical Assessment

• Detailed history from child (age-appropriate interviewing): Use open-ended questions ("Tell me what happened"), avoid leading questions, and document verbatim statements. Children >4 years provide increasingly reliable accounts. Document exact quotes. Assess for disclosure reluctance (fear of consequences, ambivalence about abuse). Use anatomically correct dolls or drawings only as communication aids, not for evidence gathering, due to risk of contamination.

• Detailed history from non-offending caregiver: Document the reported mechanism of injury with specific details (date, time, location, witnesses, immediate responses). Compare to child's account. Assess for inconsistencies, implausibility given child's developmental stage (e.g., 6-month-old rolling off changing table when not yet rolling), delays in seeking care, or changing stories.

• Physical examination with documentation: Perform complete physical exam, particularly inspecting all skin surfaces, genitals, anus, and mouth under good lighting. Photograph injuries with ruler for scale and patient identifier (per institutional protocol). Document location, size, shape, color, and pattern of each injury. Perform full eye examination including dilated retinal exam with documentation of retinal hemorrhages. Assess neurodevelopmental status and behavioral presentation.

Laboratory Testing

• Coagulation studies (PT, aPTT, platelet count): Normal coagulation studies help exclude bleeding disorders that might predispose to bruising and complicate interpretation of injuries. Elevated INR or aPTT or thrombocytopenia suggests alternative explanation for bleeding tendency.

• Liver function tests and amylase: Elevated AST/ALT (>100 IU/L in absence of known liver disease) suggests hepatic trauma. Elevated lipase/amylase indicates pancreatic injury. These suggest abdominal trauma not explained by documented mechanism.

• Sexually transmitted infection screening: Nucleic acid amplification tests (NAATs) for gonorrhea and chlamydia from genital, anal, and pharyngeal sites (higher sensitivity than culture). RPR/VDRL with reflex FTA-ABS for syphilis. HSV and HPV serology (though HPV presence is not diagnostic without additional findings). HIV testing at baseline and 6 weeks, 3 months, 6 months. Positive STI diagnosis in prepubertal child is virtually pathognomonic for sexual abuse.

• Pregnancy testing: Serum or urine hCG in all postmenarchal girls with abuse concern.

Imaging

• Skeletal survey for suspected physical abuse: Radiographs of all long bones, spine, chest, pelvis, and skull with dedicated attention to metaphyses. High specificity for abuse findings: metaphyseal/corner fractures, posterior rib fractures, sternal fractures, scapular fractures. Sensitivity of skeletal survey is only 60-75%; therefore, repeat skeletal survey at 2 weeks (new callus formation makes healing fractures more visible) improves detection. Consider bone scintigraphy (technetium-99m bone scan) for detection of rib, sternal, and metaphyseal fractures in younger children or when initial survey is negative but suspicion remains high.

• Head CT (non-contrast): Subdural hematoma (especially bilateral), subarachnoid hemorrhage, cerebral contusions, diffuse axonal injury, and cerebral edema are characteristic findings. CT has high sensitivity for acute intracranial injury but may miss subtle DAI; therefore, brain MRI should be obtained in cases with clinical suspicion of NAHT or abnormal neurodevelopmental status.

• Brain MRI: Provides superior soft tissue resolution for DAI, contusions, and late-stage hemorrhage. Use of susceptibility-weighted imaging (SWI) enhances detection of microhemorrhages. Detects injuries in posterior fossa and corpus callosum missed on CT.

• Abdominal/pelvic CT or ultrasound: For suspected abdominal trauma, CT with IV contrast evaluates for solid organ injuries (liver, spleen, pancreas), bowel perforation (free air), and retroperitoneal bleeding. Abdominal ultrasound is less sensitive

Immediate stabilisation (medical needs precede forensic and legal ones)

• Airway, breathing, circulation per PALS/AAP resuscitation standards: intubate for GCS ≤8 or apnea from abusive head trauma; isotonic crystalloid and blood products for hemorrhagic shock from liver, splenic, or mesenteric injury.
• Raised intracranial pressure: head-of-bed elevation, normoxia and normocarbia (avoid prophylactic hyperventilation), and hyperosmolar therapy — hypertonic saline is first-line in the Brain Trauma Foundation pediatric severe TBI guidance, with mannitol as an alternative. Anticonvulsants: levetiracetam or fosphenytoin for clinical or electrographic seizures; non-convulsive status is common, so continuous EEG is indicated in the obtunded infant.
• Definitive/surgical: neurosurgical evacuation of a mass-effect subdural hematoma or decompressive craniectomy; laparotomy or angioembolisation for ongoing intra-abdominal bleeding or bowel perforation; orthopedic fixation/immobilisation of fractures; burn fluid resuscitation and debridement.

Protection and reporting (the step examiners test)

• Mandated report to child protective services based on reasonable suspicion, not proof — required of all clinicians under CAPTA-based state law, with statutory immunity for good-faith reports. Do not wait for the skeletal survey, consultant opinion, or a confession.
• Admit for safety even when injuries alone would not require it; involve a child abuse pediatrician, social work, and a Child Advocacy Center multidisciplinary team (AAP Committee on Child Abuse and Neglect). Evaluate household contacts <2 years with their own skeletal survey.

Sexual abuse–specific therapy (CDC STI Treatment Guidelines, 2021)

• Adolescents/postpubertal: presumptive ceftriaxone IM plus doxycycline, with metronidazole for trichomoniasis; HIV nPEP (tenofovir/emtricitabine plus an integrase inhibitor such as raltegravir or dolutegravir) started within 72 hours; hepatitis B and HPV vaccination; levonorgestrel emergency contraception within 120 hours (ACOG).
• Prepubertal children: test rather than treat presumptively — culture/NAAT results carry forensic weight.
• Trauma-focused CBT is first-line for PTSD (AACAP practice parameter); an SSRI such as sertraline is adjunctive. Avoid benzodiazepines.

Neurologic (highest mortality)

• Cerebral herniation from expanding subdural hematoma or malignant cerebral edema — emergency; signalled by pupillary asymmetry, Cushing triad (hypertension, bradycardia, irregular respirations), or abrupt GCS drop. Mechanism: fixed cranial volume plus hypoxic-ischemic secondary injury.
• Post-traumatic epilepsy, spastic cerebral palsy, cortical blindness, and cerebral atrophy with ex vacuo ventriculomegaly: months later, from diffuse axonal injury and infarction; abusive head trauma survivors have high rates of permanent disability.
• Retinal detachment, macular scarring, and vision loss from severe multilayered retinal hemorrhage.

Systemic and orthopedic

• Hemorrhagic shock from liver/splenic laceration and peritonitis from duodenal or jejunal perforation — emergencies; blunt abdominal trauma is the second leading cause of abuse death. Rising transaminases or lipase, abdominal distension, or free air demand imaging.
• Growth arrest, limb deformity, or nonunion from untreated or repeatedly re-injured metaphyseal and physeal fractures.
• Burn wound sepsis and contracture from delayed presentation of immersion injuries.

Complications of neglect and of refeeding

• Refeeding syndrome — emergency; aggressive caloric repletion in a severely malnourished child drives insulin-mediated intracellular shift of phosphate, potassium, and magnesium, producing hypophosphatemia, arrhythmia, and heart failure. Advance calories slowly and monitor electrolytes.

Recurrence and psychiatric sequelae

• **Re-abuse after a missed *sentinel injury***: a small unexplained bruise or intraoral frenulum tear in a pre-mobile infant returned home is frequently followed by far more severe injury or death — the single most consequential complication of under-reporting.
• PTSD, depression, self-harm and suicidality, substance use, and disorganised/reactive attachment, mediated by HPA-axis dysregulation; adverse childhood experience burden predicts adult cardiometabolic and psychiatric disease.

Treatment-related

• HIV nPEP intolerance (nausea, poor adherence) and antibiotic adverse effects.
• Iatrogenic harm from an unfounded report: family disruption and loss of trust — mitigated by neutral documentation, not by withholding a good-faith report.

• "Those who don't cruise rarely bruise": any bruise in a non-ambulatory infant is a sentinel injury until proven otherwise. Apply the TEN-4 rule (Torso, Ear, Neck bruising, or any bruise in a child <4 months/<4 years). Best next step: skeletal survey plus a CPS report.
• Single best next step in almost every stem: report to child protective services on reasonable suspicion. You do not need certainty, a confession, imaging confirmation, or a supervisor's approval; good-faith reporting carries statutory immunity under CAPTA-based state law. "Reassure and follow up in one week" is always the wrong answer.
• Pathognomonic radiology: classic metaphyseal lesion (corner/bucket-handle fracture) and posterior rib fractures. The AAP and ACR Appropriateness Criteria call for a skeletal survey in every child <2 years with suspected physical abuse, with a repeat survey ~2 weeks later, and screening of household contacts <2 years.
• Abusive head trauma triad: subdural hematoma (often bilateral, over convexities) + retinal hemorrhages that are multilayered, too numerous to count, and extend to the ora serrata + encephalopathy. A few posterior-pole hemorrhages after a short fall or birth do not count.
• The association examiners love: gonorrhea or syphilis in a prepubertal child is diagnostic of sexual abuse. Chlamydia beyond infancy is likewise abuse-indicative; HSV and HPV can be perinatally acquired, so they are suspicious but not conclusive.
• Common distractors: osteogenesis imperfecta (blue sclerae, Wormian bones, family history), congenital dermal melanocytosis (Mongolian spots — slate-grey, sacral, present since birth), coining/cupping, ITP or hemophilia, leukemia, vitamin K deficiency bleeding, and rickets. Screen coagulation and calcium/vitamin D — but an alternative diagnosis is excluded, not assumed.
• Sexual abuse timing: HIV nPEP within 72 hours, levonorgestrel emergency contraception within 120 hours (CDC/ACOG). A normal anogenital exam never excludes sexual abuse.