Asymptomatic Infant Rib Fractures Are Primarily Non-abuse-Related and Should Not Be Used to Assess Physical Child Abuse.

Finding infant rib fractures was for many years an almost undisputed proof that physical child abuse took place. Yet, these rib fractures are virtually always occult and asymptomatic and are only identified when looked for, usually with X-rays, from physical child abuse accusations related to, e.g., suspicion of the shaken baby syndrome. In a recent systematic literature review (searched in Cochran, Embase, PubMed and Sociological Abstracts), Güvensel questioned the diagnostic accuracy of rib fractures to be caused by abuse, due to lack of sufficient scientific evidence. Further, there is currently a world-wide disagreement between physicians considering themselves child abuse specialized, and physicians that explore non-abuse-related symptoms that may mimic physical abuse, which, it is hoped, will significantly reduce current unjustified child abuse diagnoses. In an attempt to help resolving this disagreement, we hypothesize that the probability of physical child abuse-related infant rib fractures is significantly lower than the probability of all other possible non-abuse-related causes of occult asymptomatic infant rib fractures, e.g., from birth trauma, prematurity, osteogenesis imperfecta, hypermobile Ehlers-Danlos Syndrome, severe chronic placental pathology (e.g., massive perivillous fibrin depositions and severe chronic histiocytic intervillositis), and vitamin-D deficiency. As method, we attempted to assess the incidence of these various causes of infant rib fractures, in the Netherlands and the USA. The results are that the estimated Dutch and USA physical abuse-related infant rib fracture incidences are at least about 250 and 45 times lower than the sum of all the non-abuse-related estimates. Because these latter rib fractures are occult and asymptomatic, it is likely that (many) more could be out there. In conclusion, occult asymptomatic rib fractures develop perinatally, virtually always as birth trauma, in infants with sufficiently weak bones due to vitamin D deficiency, transmitted by their vitamin D deficient pregnant mothers. This group also includes cortical rib cracks due to deformation forces, with an estimated 186/100,000 incidence. And, despite obvious uncertainties in all estimated incidences, we provided strong evidence that our hypothesis has relevance, implying that the abundant occult asymptomatic rib fractures, when found in infants, should not be used to assess potential physical child abuse.

Child Abuse, Misdiagnosed by an Expertise Center: Part I-Medico-Social Aspects.

Child abuse is a dangerous situation for an infant. Professionals need to weigh the risk of failing to act when children are seriously harmed against the serious harm done by carrying out safeguarding interventions. In severe cases, foster care might be advisable. The negative effects for the child's psychosocial development requires that such placement must be based on very solid evidence. Our aim is to identify why Dutch parents whose child may have a medical condition that could mimic symptoms of child abuse have a significant chance of being erroneously convicted and losing custody of their child. As a method, we describe and analyze the following case. An Armenian-Dutch newborn (uncomplicated term vaginal delivery), starting at two weeks after birth, developed small bruises on varying body locations. At two months, a Well-Baby Clinic physician referred the girl to a university hospital, mentioning that there were no reasons to suspect child abuse and that her Armenian grandmother easily bruised as well. However, before consultation by a pediatrician of the hospital-located Expertise Center for Child Abuse, the parents were suspected of child abuse. Based on the expertise center's protocols, skeletal X-rays were made, which showed three healed, asymptomatic rib fractures, while invalid statistics suggested, incorrectly, a 10-100 times more likely non-accidental than accidental cause of the symptoms (discussed in Part II of this series). The expertise enter physician ignored any argument that could show parental innocence, including the positive parent-child relationship reported by the Well-Baby Clinic and the general practitioner. The girl and her older brother were placed in a family foster home and then in a secret home. The case radically resolved when a large bruise also developed there, and an independent tissue disease specialist diagnosed a hereditary connective tissue disorder in the mother, implying that the girl's bruises and rib fractures could well be disease-related. In conclusion, if child abuse is suspected, and foster care placement considered, the patient and the parents should be thoroughly investigated by an independent experienced pediatrician together with an experienced pediatric clinical psychologist or psychotherapist to produce an independent opinion. Children deserve this extra safeguard before being separated from their parents.

Child Abuse, Misdiagnosed by an Expertise Center-Part II-Misuse of Bayes' Theorem.

A newborn girl had, from two weeks on, small bruises on varying body locations, but not on her chest. Her Armenian grandmother easily bruised, too. Her mother was diagnosed with hypermobility-type Ehlers-Danlos-Syndrome (hEDS), an autosomal dominant connective tissue disorder, with a 50% inheritance probability. Referral to a University Medical Center located "Dutch Expertise Center for Child Abuse" resulted (prior to consultation) in physical abuse suspicion. Protocol-based skeletal X-rays showed three healed, asymptomatic rib fractures. A protocol-based Bayesian likelihood ratio guesstimation gave 10-100, erroneously used to suggest a 10-100 times likelier non-accidental-than-accidental cause. Foster care placement followed, even in a secret home, where she also bruised, suggesting hEDS inheritance. Correct non-accidental/accidental Bayes' probability of symptoms is (likelihood ratio) × (physical abuse incidence). From the literature, we derived an infant abuse incidence between about ≈0.0009 and ≈0.0026 and a likelihood ratio of <5 for bruises. For rib fractures, we used a zero likelihood ratio, arguing their cause was birth trauma from the extra delivery pressure on the chest, combined with fragile bones as the daughter of an hEDS-mother. We thus derived a negligible abuse/accidental probability between <5 × 0.0009 <0.005 and <5 × 0.0026 <0.013. The small abuse incidence implies that correctly using Bayes' theorem will also miss true infant physical abuse cases. Curiously, because likelihood ratios assess how more often symptoms develop if abuse did occur versus non-abuse, Bayes' theorem then implies a 100% infant abuse incidence (unwittingly) used by LECK. In conclusion, probabilities should never replace differential diagnostic procedures, the accepted medical method of care. Well-known from literature, supported by the present case, is that (child abuse pediatrics) physicians, child protection workers, and judges were unlikely to understand Bayesian statistics. Its use without statistics consultation should therefore not have occurred. Thus, Bayesian statistics, and certainly (misused) likelihood ratios, should never be applied in cases of physical child abuse suspicion. Finally, parental innocence follows from clarifying what could have caused the girl's bruises (inherited hEDS), and rib fractures (birth trauma from fragile bones).

Hypothesized pathogenesis of acardius acephalus, acormus, amorphus, anceps, acardiac edema, single umbilical artery, and pump twin risk prediction.

BACKGROUND: Acardiac twinning complicates monochorionic twin pregnancies in ≈2.6%, in which arterioarterial (AA) and venovenous placental anastomoses cause a reverse circulation between prepump and preacardiac embryos and cessation of cardiac function in the preacardiac. Literature suggested four acardiac body morphologies in which select (groups of) organs fail to develop, deteriorate, or become abnormal: acephalus (≈64%, [almost] no head, part of body, legs), amorphus (≈22%, amorphous tissue lump), anceps (≈10%, cranial bones, well-developed), and acormus (≈4%, head only). We sought to develop hypotheses that could explain acardiac pathogenesis, its progression, and develop methods for clinical testing. METHODS: We used qualitatively described pathophysiology during development, including twin-specific AA and Hyrtl's anastomoses, the short umbilical cord syndrome, high capillary permeability, properties of spontaneous aborted embryos, and Pump/Acardiac umbilical venous diameter (UVD) ratios. RESULTS: We propose that each body morphology has a specific pathophysiologic pathway. An acephalus acardius may be larger than an anceps, verifiable from UVD ratio measurements. A single umbilical artery develops when one artery, unconnected to the AA, vanishes due to flow reduction by Hyrtl's anastomotic resistance. Acardiac edema may result from acardiac body hypoxemia combined with physiological high fetal capillary permeability, high interstitial compliance and low albumin synthesis. Morphological changes may occur after acardiac onset. Pump twin risk follows from UVD ratios. CONCLUSION: Our suggested outcomes agree reasonably well with reported onset, incidence, and progression of acardiac morphologies. Guidance for clinical prediction and testing requires ultrasound anatomy/circulation study, from the first trimester onward.

Why does second trimester demise of a monochorionic twin not result in acardiac twinning?

BACKGROUND: We previously explained why acardiac twinning occurs in the first trimester. We raised the question why a sudden demised monochorionic twin beyond the first trimester does not lead to acardiac twinning. We argued that exsanguinated blood from the live twin would strongly increase the demised twins' vascular resistance, preventing its perfusion and acardiac onset. However, our current hypothesis is that perfusion of the demised twin does occur but that it is insufficient for onset of acardiac twinning. METHODS: We analyzed blood pressures and flows in a vascular resistance model of a monochorionic twin pregnancy where one of the fetuses demised. The resistance model consists of a demised twin with a (former) placenta, a live twin and its placenta, and arterioarterial (AA) and venovenous placental anastomoses. We assumed that only twins with a weight of at least 33% of normal survived the first trimester and that exsanguination of more than 50% of its blood volume is fatal for the live twin. RESULTS: At 20 weeks, only AA anastomoses with radii ≲1 mm keep the exsanguinated blood volume below 50%. Then, perfusion of the deceased body with arterial blood from the live fetus is about 5-40 times smaller than when that body was alive. Beyond 20 weeks, this factor is even smaller. At 14 weeks, this factor is at most 2. CONCLUSION: We hypothesize that this small perfusion flow of arterial blood prevents further growth of the deceased body and hence precludes onset of acardiac twinning.

Acardiac twin pregnancies part V: Why does an acardiac twin with renal tissue produce polyhydramnios?

BACKGROUND: Acardiac twinning is a complication of monochorionic twin pregnancies. From literature reports, 30 of 41 relatively large acardiac twins with renal tissue produced polyhydramnios within their amniotic compartment. We aim to investigate the underlying mechanisms that cause excess amniotic fluid using an established model of fetal fluid dynamics. METHODS: We assumed that acardiac onset is before 13 weeks, acardiacs with renal tissue have normal kidney function and produce urine flow from 11 weeks on, and acardiac urine production requires a pressure of half the pump twin's mean arterial pressure. We apply a resistance network with the pump twin's arterio-venous pressure as source, pump umbilical arteries, placenta, placental arterio-arterial (AA) anastomoses and acardiac resistances. Acardiac amniotic fluid dynamics excluded acardiac lung fluid secretion, swallowing and the relatively small intramembranous flow. RESULTS: In small acardiacs with sufficient urine production, polyhydramnios will occur due to the lack of amniotic fluid resorption. Urine production is dependent upon having sufficient mean arterial pressure, which requires nearly a two-fold larger resistance within the acardiac as compared to the placental AA resistance. Subphysiologic arterial pressure may result in renal dysgenesis. CONCLUSION: Our findings suggest the potential for prediction of which clinical acardiac cases may or may not develop polyhydramnios based upon noninvasive assessments of renal tissue, blood flow and urine production. This information would be of great value in determining early obstetric interventions as opposed to conservative management. These findings may also contribute to an improved knowledge of the fascinating pathophysiology that surrounds acardiac twinning.