1. Human sleep cycles are affected by the phase of the moon, even when they cannot see the light: researchers at the University of Basel re-analyzed old data attained during a sleep study where people were kept inside for long stretches of time, and found that people slept worse on nights when there was a full moon, even when they couldn't have possibly been affected by the light since they were inside for days on end. Quote: "Electroencephalography showed that the volunteers slept, on average, 20 minutes less around the time of the full Moon. It also took them five minutes longer to get to sleep, their delta activity (a measure of how deeply they were sleeping) was 30% lower than at other times, their level of melatonin, a sleep-related hormone, was reduced, and they reported, subjectively, that they had not slept as well as usual. Nor was any of this connected, in female volunteers, with their menstrual cycles." (economist)
2. Hep B immune globulin is expensive, so you don't want to administer it to a neonate unless you have positive Heb B serologies from mom during pregnancy. You don't want to give it to every infant of a mom with unknown Hep B status.
3. To determine whether blood is maternal or fetal, you can use the following tests:
-Apt test: generally a test of secreted blood to see if it is maternal or fetal, i.e. 3rd trimester vaginal bleeding to r/o vasa previa (although if you really suspect previa, don't take the time to do this test, run to surgery) or spit-up from a neonate to figure out if its swallowed maternal blood or infant GI bleed (usually brighter red in color). Technique: put blood into tap water to lyse cells. Spin down, take supernatant (where Hb is), add strong base (KOH, NaOH). Fetal hemoglobin will remain red/pink, but maternal hemoglobin will denature to hematin (turn brown-yellow).
-Kleihauer-Betke: a test of maternal blood to ascertain presence of fetal blood cells. Good to determine extent of maternal-fetal transfusion. Strong acid denatures maternal Hb, but not fetal. So smear the blood on a slide, put it in an acid bath, look under the microscope. Maternal cells will be "ghosted" pale, while fetal red cells will be bright red and normal.
4. Vascular lesions on back/lower back of neonate: blanching suggests vascular malformation (hemangioma). The presence of 2 or more abnormalities on the lower back of a neonate (hair tuft, abnormal/asymmetrical cleft, distorting mass/lipoma, stain, skin tag, dimple) is more suggestive of an occult spinal dysraphism and should be worked up with MRI; single abnormality is overwhelmingly unlikely to be associated with spinal findings and should be worked up with u/s.
5. Caput succedaneum: "boggy" area on baby's head, common finding after delivery, happens from the pressure of baby's head against the dilating cervix (tourniquet effect). Subcutaenous/extraperiosteal collection of serosanguinous fluid, crosses sutures/midline. Resolves spontaenously after a few days.
6. Subgaleal hemorrhage: bleeding under the periosteum, above the skull. Associated with vacuum operative deliveries. Does not cross suture lines. Can lead to increased risk of jaundice. Feels fluctuant upon palpation. Will absorb slowly over weeks-- do not aspirate as it carries a risk of infection/abscess formation. Get imaging if new neuro sx appear. After it absorbs, it may calcify, leaving a relatively softer center and giving the impression of a depressed fracture.
7. The three most common causes of ataxia in a child:
--Postinfectious acute cerebellar ataxia (usu s/p varicella, GI or respiratory infection.)
--Ingestion: barbituates, alcohol, antifreeze, lead, CO, benzos, benadryl
--Guillain-Barre: acute symmetrical ascending demyelinating autoimmune/inflammatory disease. Associated with campylobacter infection.
8. Can't-miss causes of ataxia in a child: 
--Infection (meningitis/encephalitis/sepsis)
--Brain abscess
--Tumor
--Bleed (2/2 trauma, NAT)
--Post-infectious autoimmune (ADEM)
--ICP
--Ischemia (clot, moya moya)
9. Other auses of ataxia in a child:
--Tick paralysis/lyme disease
--Neuromuscular disease (muscular dystrophy, injury, myasthenia)
--Vestibular system disease (labrynthitis- often s/p URI, menieres)
--Basilar migraine
--Seizure, post-ictal
10. Posterior fossa mutism-- happens in 8-38% of children who receive resection of posterior fossa tumors, specifically medulloblastoma. Usually transient, speech returns in 1-15 weeks. Almost always accompanied by cerebellar ataxia.