Renal/GU Polyuria/freq Endo: diabetes mellitus; CNS: central diabetes insipidus, spinal cord pathology, MS; psych: diuretic abuse, polydipsia, sexual abuse Oliguria/retention Pulmonary and CNS: SIADH; CNS: spinal cord injury, demyelinating disease HematuriaHematol: bleeding diathesis, anticancer drugs; psych: factitious CNS Headache Renal: hypertension; ENT: sinusitis, psychogenic Seizure Metabolic: hypoglycemia, hyper/hypoelectrolytemias, hypocalcemia, inborn errors of metabolism; renal: uremia; psych: syncope, hyperventilation, narcolepsy; cardiac: arrhythmia; GI: GERD (Sandifer syndrome) Altered consciousness Renal: uremia; hepatic: liver failure; endo: hypoadrenalism, DKA, hypoparathyroidism, (lethargy, agitation) hyperthyroidism; metabolic/toxic : Wilson disease, poisoning; pulmonary: CO 2 narcosis Focal weakness Ortho: bone pain (Parrott’s paralysis owing to injury, tumor, rickets, scurvy) Psych PsychosisGI: Liver failure; GU: uremia; heme: porphyria lupus erythematosis; metab: Wilson disease AnxietyEndo: hyperthyroidism, catecholamine excess, hypoparathyroidism; pulm: hypoxia; toxic: medications (steroids, catecholamines) Endo Poor linear Renal, infectious, cardiac, pulmonary: chronic conditions of almost any kind growth Late puberty GI: IBD; psych: eating disorders; CNS: craniopharyngioma; heme-onc: late effects of cancer treatment Abbreviations: CNS = central nervous system; DKA = diabetic ketoacidosis; GERD = gastroesophageal reflux disease; GI = gastrointestinal; GU = genitourinary; SIADH = syndrome of inappropriate antidiuretic hormone s ecretion; UTI = urinary tract infection; ENT = ear, nose, throat; PID = pelvic inflammatory disease; ICP = intra-cranial pressure. 65 right lower quadrant tenderness, no guarding or rebound tenderness, and decreased bowel sounds, we may hypothesize a diagnosis of ap- pendicitis and feel the need to look further into the matter. Step 5: Test the hypotheses. Comments: It is possible that our patient may be experiencing an early stage of appendicitis. Now invoke laboratory and imaging. Step 6: Modify your differential diagnosis. Comments: If a complete blood count reveals a normal white blood c ell count, and the urinalysis is normal, we may decide on a diagnosis of gastroenteritis based on the preponderance of evidence. How- ever, if the white blood cell count is elevated, this may militate more toward a diagnosis of appendicitis, although it is by no means an absolute certainty at this point. Always keep in mind that if a labo- ratory test result is not consistent with the clinical picture, repeat it. M istakes in specimen handling and procedure do occur. Step 7: Repeat steps 1 to 6. Comment: Have we forgotten something? Have we left out any histori- cal points? Do we have a travel history? Are there any pets in the home? Are there any other possibl e exposures? Did the patient have a rectal examination? Although one may not perform a rectal ex- amination on every patient, it seems necessary to perform one now. Step 8: Make the diagnosis or diagnoses. Comment: If the answer is certain, stop at this point. As for our patient with the possible diagnosis of appendicitis, where do we go from here? Step 9: If uncertain, consider a provisional diagnosis or watchful waiting. Comments: We are st ill in the battlefield of fact versus opinion. We do not have enough facts to make a definitive diagnosis at this time. Now is the time to ask the questions: “How much uncertainty can I tolerate?” and “What do I want to know, and when do I want to kn ow it?” There are options. One may decide to reexamine the pa- tient to determine if there are any changes that would indicate that the diagnosis of appendicitis is declaring itself clinically. Are we run- ning the risk of a rupture if we wait too long? Is it logistically pos- sible for both doctor and patient to meet again in 4 hours? Another choice would be to obtain a CT scan of the abdomen. Can we sched- ule this on short notice? Does the patient have coverage to pay for this more expensive study? Will we save any more time than re- peating an examination in 4 hours? Another option is to call for a surgical consultation. Does the community have a pediatric sur- geon? Are we p repared to have our patient operated on now? Sometimes there remains not a questionable diagnosis but rather several possibilities. After answering the question “What do I want to know, and when do I want to know it?” and fee ling comfortable that deferring one or more of the diagnoses will not carry dire con- sequences, one may make further attempts to narrow the possibili- ties by applying the principle of parsimony. This i s known as Occam’s razor or lumping as opposed to splitting. This approach is often more helpful in younger patients than in the elderly, who are more likely to have multiple problems. Another tool for prioritizing diagnoses 66 Chapter 4: Development of a Differential Diagnosis is to place them in their order of probability. The old saw that “com- mon things occur commonly” is helpful, but one must decide to pur- sue rarer diagnoses in a timely fashion, if necessary. This exercise illustrat es both the objectivity and subjectivity involved in making medical diagnoses. Although we strive to use the scientific method, there is still much uncertainty in our professional lives. Edu- cation , experience, and knowledge will lessen but never eradicate uncertainty. In summary, to quote Sir William Osler: “The practice of medicine is an art, based on science.” Computers in Differential Diagnosis Most of the steps in the diagnostic framework require the knowledge and experience of a trained human eye (and ear and hand and some- times a nose). Certainly the physical examination cannot be deleg ated to an untrained person—and definitely not to a machine. It is the province of the physician to take the steps involving judgment and rea- soning. However, it is possible to automate some of these steps, es- peci ally those involving correlation of information and generation of potential differential diagnoses. The present-day ubiquity of computers allows us to automate these steps. In the simplest terms, a computer is a calculating machine that per- for ms its calculations in a predefined sequence (a program) and that can run different parts of the program based on decisions (Is A less than, equal to, greater than, or not equal to B?). We humans can do this, too, and we are much mo re flexible in our thinking than are computers, but computers can calculate much faster than we can. The computers used to write this book perform well over 1 billion operations each second. Computers have no inherent ability to reason. T heir “reasoning abil- ity” comes from their (human-designed) programming. Their main ben- efit to us is in the speed with which they can process information and make their “decisions.” The best-kn own benefit of high-speed comput- ing is management and use of the medical literature, which is now far too extensive to be manageable without computers. Evidence-based medicine as we now use it would be impossible wi thout Internet-based literature search tools, and the mere act of searching the literature for information is useful to correlate and compare candidate differential diagnoses. However, physicians and medical infor maticians have de- veloped and continue to refine programs that can give clinicians more specific and helpful aids to diagnosis. These tools may suggest differ- ential diagnoses or recommend addition al diagnostic studies beyond those the clinician has already obtained. For example, such a program, when “told” that an adolescent girl has palatal lacerations, dental ero- sion, and abrasions over the dorsal knuckles of her right hand, wi ll sug- gest obtaining amylase, lipase, and potassium levels. Some will even suggest therapies, as well as recommend-against ther- apies that may be harmful (such as checking medication lists for agents to which a patient has allergies). Computerized physician ord er entry Computers in Differential Diagnosis 67 (CPOE) systems take this one step further by suggesting additional or ders (usually based on clinical pathways or protocols) or flagging pos- sibly inappropriate orders. Some well-written decision-support programs have yielded “correct” diagnoses at a higher rate than physicians in comparative trials, but this result may be misleading because even experienced and expert physi- cians may consider the same patien t’s case and not come to the same diagnostic conclusion. Remember that it is the physician who creates the program—the computer merely memorizes and sorts data very effi- ciently. These pr ograms are not to override the physician’s clinical judgment—the physician remains professionally and legally responsible for the patient’s care—but they may be a useful adjunct to the diagnostic process, especially wi th the exponential growth of medical knowledge. 68 Chapter 4: Development of a Differential Diagnosis 69 The Term Newborn 5 Chapter Although the neonatal period is defined as the first 4 weeks of life, we limit this chapter to evaluation in the term newborn nursery. Our goals include 1. To develop a prenatal history encompassing early, middle, and late pregnancy and delivery. We will emphasize maternal medical, fam- ily, and social history; monitoring for prenatal diagnosis; and fetal monitoring at labor and delivery. 2. To review a thorough healthy newborn assessment. We examine by region and evaluate each for inspection, palpation, percussion, and auscultation where applicable. 3. Since newborns cannot provide histories, we will assess in lieu of symptoms key postnatal problems as reported by a caretaker or a health professional. 4. To assess pathologic signs and, in conjunction with prenatal history, physical examination, and laboratory and imaging studies, to syn- thesize diagnoses. We will develop a clinical approach to the most common problems that a neonatal nurse will report: growth problems, large-for-gestational age (LGA) and small for gestational age (SGA), temperature instability (hyper/hypothermia), tachypnea and apnea, vomiting, lethargy/poor feeding, irritability/jitteriness, seizures, pallor/plethora, cyanosis, heart murmurs, jaundice, and dermatologic conditions. Please refer to Chapter 6 for discussion of dysmorphology. Prenatal History Infectious Gather a thorough history on any maternal infec- tious illness during the pregnancy. Most likely the mother was screened for group B streptococcal infection. If she was positive, was she treated ade- quately with antibiotics during labor (doses every 4 hours, with last dose within 4 hours of delivery)? Were there any exposures to other bacte- ria, such as Escherichia coli (maternal urinary tract infection), Listeria, or Mycobacterium tuberculosis? Did the mother have any sexually transmit- ted infections such as syphilis, gonorrhea, human immune-deficiency virus Arthur N. Feinberg KEY MATERNAL PROBLEM Copyright © 2008 by The McGraw-Hill Companies, Inc. Click here for terms of use. (HIV), Chlamydia, or Ureaplasma? Viral infections during early pregnancy such as rubella, cytomegalovirus, and varicella will cause fetal malforma- tions. Hepatitis B and C will cause disease in newborns owing to mater- nal transmission. Herpes simplex types 1 and 2 may produce a sepsis-like picture and can be overwhelming and devastating. Also, Enterovirus will cause a sepsis-like picture with jaundice, myocarditis, or meningitis. Parasitic infestations, specifically toxoplasmosis, also will cause fetal anom- alies. A careful travel history will help to elucidate possible exposures to other parasites. Noninfectious Maternal medical history is important. Ask about common conditions such as diabetes mellitus, hypertension, endocrinologic disorders such as hypo/hyperthyroidism, and maternal immunologic disorders that predispose to antibody transmission across the placenta (immune thrombocytopenic purpura, myasthenia gravis, collagen- vascular disorders, etc.) because they have profound effects on newborns. Maternal pulmonary, cardiac, renal, hematologic/oncologic, and neuro- logic disorders may play a role in newborn outcome, as will many of the medications used to treat these conditions. Are there any poten- tially inheritable conditions? 70 Chapter 5: The Term Newborn KEY MATERNAL PROBLEM TABLE 5–1 Noninfectious Maternal Conditions Affecting the Newborn Maternal Condition Newborn Findings Congenital heart disease Intrauterine growth retardation (IUGR) Diabetes mellitus Hypoglycemia, hypocalcemia, polycythemia, large for gestational age (LGA), microcolon, asymmetric septal hypertrophy, caudal regression syndrome Hypertension IUGR Obesity Macrosomia, hypoglycemia Hyperthyroidism Transient neonatal thyrotoxicosis Hypothyroidism Neonatal hypothyroidism Hyperparathyroidism Neonatal hypocalcemia Immune thrombocytopenic Neonatal thrombocytopenia purpura Myasthenia gravis Transient weakness Malignancy Metastasis, fetal effects of treatment Sickle cell anemia IUGR Systemic lupus Rash, anemia, thrombocytopenia, erythematosus neutropenia, third-degree heart block IUGR Renal failure Fetal effects of medications (see TABLE 5–3) Seizure disorder Adapted from Stoll BJ, Kliegman RM (eds.): Nelson Textbook of Pediatrics, 17th ed. Philadelphia: Elsevier/Saunders, 2004: p. 533, with permission from Elsevier. It is critical to obtain a full environmental and social history. Is the fetus at risk because of homelessness or unsanitary surroundings? Does the mother have a history of substance abuse, including tobacco, alcohol, and/or street drugs? Was there exposure to environmental hazards such as chemicals or pesticides? Evaluate any medication the mother took during the pregnancy for any effect on the fetus or new- born, either teratogenic or symptomatic. TABLES 5–1 through 5–3 list maternal conditions and fetal exposures that may be problematic. Prenatal History 71 TABLE 5–2 Infectious Maternal Conditions and Their Fetal Effects Maternal Condition Newborn Findings Bacterial Group B streptococcus Sepsis, pneumonia, meningitis E. coli Sepsis, pneumonia, meningitis Klebsiella, Proteus, Sepsis, pneumonia, meningitis Pseudomonas Neisseria gonorrhoeae Sepsis, pneumonia, meningitis, conjunctivitis (ophthalmia) Mycoplasma pneumoniae Pneumonia Chlamydia trachomatis Conjunctivitis Syphilis Snuffles, rhagades, saddle-nose deformity, metaphysitis, jaundice, hepatosplenomegaly (HSM) Viral Rubella IUGR, cataracts, microphthalmia, HSM, pulmonic stenosis, patent ductus, deafness, “blueberry muffin” skin (thrombocytopenia) Varicella embryopathy Cicatrix scarring, poor limb development, multiple eye, brain, and spinal cord abnormalities Perinatal disease Severe chickenpox, pneumonia, hepatitis, encephalitis Cytomegalovirus (CMV) IUGR, HSM, jaundice, purpura, embryopathy microcephaly, cerebral calcifications, chorioretinitis, deafness Perinatal disease Pneumonia, sepsislike picture Herpes Hominis SEM (skin-eye-mucous membrane), encephalitis, systemic (hepatic) Hepatitis B, C Neonatal hepatitis B, C infection Parvovirus B-19 Anemia, fetal hydrops Enterovirus (echo- Sepsis picture, jaundice, myocarditis, coxsakie) meningitis Parasitic toxoplasmosis Similar to CMV + hydrocephalus (embryopathy) Adapted from Stoll BJ, Kliegman RM (eds.): Nelson Textbook of Pediatrics, 17th ed. Philadelphia: Elsevier/Saunders, 2004: p. 534, with permission from Elsevier. 72 Chapter 5: The Term Newborn TABLE 5–3 Teratogenic Effects of Maternal Exposures during Pregnancy Agent Effect Anticancer drugs Fetal loss, malformations (aminopterin, cytoxan, azathioprine, 6MP) Busulfan IUGR, cleft palate, multiple endocrine gland abnormalities Antibiotics Aminoglycosides Deafness Tetracyclines Hypoplastic teeth, cataract, limb malformations Chloroquine Hearing loss Quinine Abortion, thrombocytopenia, deafness Nitrofurantoin Hemolytic anemia in patients with G6PD deficiency Cephalosporins Direct + Coombs’ test Sulfonamides Interfere with bilirubin protein binding, hemolysis in G6PD deficiency patients Antiseizure medications Carbamazepine Spina bifida Phenytoin ↑Fontanel, hypertelorism, facial cleft, hypoplastic nails, low hairline Valproate Midface hypopolasia, narrow bifrontal diameter, cardiac lesions, hyperconvex nails Trimethadione Midface hypoplasia, prominent forehead, up-slanted eyebrows, short up-turned nose, midline cardiac defects, genital anomalies Phenobarbital Vitamin K deficiency, sedation Anti-inflammatory drugs Salicylates Bleeding, prolonged gestation Ibuprofen Oligohydramnios, pulmonary hypertension Indomethacin Oliguria, oligohydramnios, pulmonary hypertension, intestinal perforation Antihypertensive drugs Atenolol IUGR, hypoglycemia Propranolol Hypoglycemia, bradycardia, apnea Reserpine Stuffy nose, drowsiness, hypo/ hyperthermia Captopril Oligohydramnios, ↓renal function Steroid medications Progesterones, anabolic Fetal masculinization steroids Prednisone Oral clefts (Continued) Prenatal History 73 TABLE 5–3 Teratogenic Effects of Maternal Exposures during Pregnancy (Continued) Agent Effect Thyroid medications Iodide Goiter Methimazole, Goiter, hypothyroidism propylthiouracil Diuretics Acetazolamide Metabolic acidosis Thiazides Thrombocytopenia Vitamin D Hypercalcemia, supravalvular aortic stenosis Isotretinoin Multiple facial, skeletal, and cardiac (Accutane) anomalies Psychotropic drugs Thalidomide Phocomelia, deafness Lithium Ebstein anomaly Haloperidol Withdrawal Imipramine Withdrawal Fluoxetine Withdrawal, hypertonicity Environmental toxins Hyperthermia Spina bifida Mercury Deafness, blindness, peripheral neuropathy (Minamata disease) Polychlorinated biphenyls IUGR, skin lesions (PCB) Anticoagulant Coumadin Vitamin K deficiency, bleeding, hypoplastic nose, bone stippling, seizures Drugs of abuse Cocaine IUGR, microcephaly, gastroschisis, seizures Congenital heart lesions, withdrawal syndrome Amphetamines Withdrawal syndrome Opiates IUGR, sudden infant death syndrome Tobacco Medications used during labor Dexamethasone Periventricular leukomalacia Oxytocin Jaundice, hyponatremia Magnesium sulfate, Respiratory depression, lethargy, sympathomimetic meconium plug, tachycardia tocolytics Adapted from Stoll BJ, Kliegman RM (eds.): Nelson Textbook of Pediatrics, 17th ed. Philadelphia: Elsevier/Saunders, 2004: p. 541, with permission from Elsevier. [...]... dimples or sinuses If they occur further than 2 cm away from the anus, they may well communicate with the central nervous system (CNS); refer them immediately Abnormal tufts of hair in the sacral region may bespeak spina bifida, tethered cord, or other CNS abnormalities Pilonidal sinuses and cysts occur within 2 cm of the anus and are benign if the examiner sees the floor of the dimple If not, ultrasound... FIGURE 5–10 Moro Response 92 Chapter 5: The Term Newborn Tonic neck When the infant is relaxed, turn the head to one side The infant will assume the en garde position with the arm that would hold the sword on the same side the head faces and the other arm flexed and held up straight (FIGURE 5–11) Traction Place fingers in the infant’s palms As he or she grasps, lifting the baby will elicit elbow and... the lateral aspect of the foot will elicit dorsiflexion of the big toe and fanning of all the others Ankle clonus Abruptly press your thumb on the ball of a foot to produce sudden dorsiflexion Normally, there should be fewer than five beats of clonus Also note that there are many tests for muscle tone that are passive Examples are the scarf sign, the heel-to-ear maneuver, the popliteal angle, and the. .. extend the legs (FIGURE 5–14) Supporting reaction Hold the infant upright with both hands around the thorax, and then gently place both feet on the surface The infant will attempt to extend both legs and straighten the trunk Placing response Similar to the supporting reaction, have the infant rub the dorsum of the foot under the edge of a bassinet or a table top FIGURE 5–11 Tonic Neck Reflex The Newborn... Similarly, pulling the infant to a sitting position or raising the infant from the supine position from the shoulders also will elicit neck flexion (FIGURE 5– 12) Perez response Hold the infant in the prone position, grasping under the abdomen Gentle rubbing up the spine will elicit flexion of the extremities and extension of the neck Similarly, elicit the Vollmer response by rubbing down the spine, which... malformations, including the palate, gingivae, and lips Is there symmetry? Are there any clefts of the lip or palate? It is most important to palpate the palate for the possibility of a submucous cleft Mucosal cysts occur commonly on the palate (Epstein’s pearls), the gingivae, and the buccal mucosa Natal teeth may occur and are often loose Remove them to prevent aspiration They may be the primary teeth but... an imaginary line that originates at the outer canthus to the ipsilateral ear, running with the slope of the eye If the ear falls below this line, it is low set To assess rotation, the angle made by intersecting lines of the vertical axis of the head and the long axis of the pinna should be less than 20 degrees Preauricular sinuses and pits, unless associated with other anomalies, are usually autosomally... spasm and indicate the need for immediate delivery Beat-to-beat variability is also an indicator of fetal well-being, the loss of which is worrisome A steady, unvarying heart rate usually indicates catecholamine production as a consequence of significant fetal hypoxia and distress The pediatrician should be aware of any abnormalities of these studies in their newborns, particularly if they are attending... Magnet Response Crossed extension reflex With the infant lying supine, straighten out one leg at the knee, and stroke the plantar surface of that foot with your other hand The opposite leg should first flex and then abduct, the toes will fan, and then the leg will extend and abduct, pointing its foot toward the foot that was stroked Figure 5–15 Placing Response The Newborn Assessment 95 FIGURE 5–16 Stepping... of the lower extremities and extension of the back Galant response Hold infant in the prone position as in the Perez response, and rub lightly along the flank The baby will move his or her buttocks toward the ipsilateral side This reflex is particularly amusing to older siblings (FIGURE 5–13) Magnet response Grasp both heels and press the thumbs on balls of infant’s feet, thus dorsiflexing them The . programming. Their main ben- efit to us is in the speed with which they can process information and make their “decisions.” The best-kn own benefit of high-speed comput- ing is management and use of the. Palpate the head. Skull bones are mobile to the point of overriding each other while pass- ing through the birth canal. There also may be skull molding (familiarly the “cone head”). The initial. experienced and expert physi- cians may consider the same patien t’s case and not come to the same diagnostic conclusion. Remember that it is the physician who creates the program the computer merely