Kaiser Wilhelm syndrome: obstetric trauma or placental insult in a historical case mimicking Erb's palsy.

Kaiser Wilhelm II of Germany (1859) developed a weak and noticeably short left arm during childhood, commonly attributed to nerve damage caused by the use of excessive force during his difficult breech delivery, Erb's palsy. However, Wilhelm's mother had a severe fall when about four months pregnant and the child was reported to be very thin at birth, suggesting intrauterine growth restriction (IUGR). Wilhelm blamed the British doctor for his deformity, and formed an enmity, which ultimately led to the 1914-1918 world war. We propose an alternative theory, considering the possibility of placental damage and consequential flow redistribution caused by the fall. In severe IUGR, the Doppler pulsatility index (PI) of the brachial arteries differs, that of the right arm being lower than the left. We used a computer model of the fetoplacental unit and reduced its functional placental area until such resistance asymmetry was produced. This would occur in extreme hypoxia when flow in the aortic isthmus is reversed, bringing right ventricular blood of lower oxygen content to the left subclavian artery. The reduced PI in the right arm is a normal vasodilatory hypoxic response, but the apparently normal PI in the left arm results from decreased demand due to metabolic failure. We suggest that the nerve damage affecting the Kaiser's left arm was due to placental insufficiency during pregnancy, and not mechanical brachial plexus injury during delivery. We further suggest that such a mechanism be called Kaiser Wilhelm syndrome to distinguish it from Erb's palsy originating from obstetric trauma.