Light and Acoustic Environment In NICU

Lighting
Planning appropriate lighting for the NICU requires consideration of the disparate needs of both the babies and staff. In general, babies need very little light, but exposure to moderate levels of   illumination during part of the day may help establish circadian rhythmicity.

The lighting will be different in many areas in the NICU as illumination of a procedure area will vary from other ambient lighting situations. Flexibility in lighting levels is required as infants' needs change at different stages of development. Control of illumination should be accessible to both staff and families, and the design should include multiple light switches. If linear fluorescent lamps are used, the color designation should be “RE80.” All fixtures should have filters or shields that block ultraviolet radiation and minimize the risk to babies and staff if a bulb should shatter.

Staff need moderate levels of illumination at the bedside to evaluate babies and to perform charting and manual tasks.

At times, intense levels of illumination are necessary to perform procedures and for phototherapy of hyperbilirubinemia. 

It is doubtful that babies need natural lighting, but studies of adult office workers and hospital patients document the benefit of windows for staff and families. A multilevel lighting scheme should be considered by the design team:

1. Ambient lighting in infant care areas.

Lighting levels are adjustable through a range of 10 to 600 lx (1 to 60 foot-candles) as measured on a

horizontal plane. A control thermistor should allow for immediate darkening if necessary. Electric light sources should have a color rendering index (CRI) of no less than 80 and a gamut area index (GA) of no less than 80 and no greater than 100. The optical reflectors in the light fixture shall have a neutral finish  and unnecessary ultraviolet or infrared radiation shall be avoided. Any ambient lighting utilized should avoid the infant's direct line of sight.

2. Procedure lighting in infant care areas.
Separate procedure lighting should be present at each infant bed and be capable of providing no less
than 2,000 lx. In addition, the light output must be framed to exclude extension beyond its illumination field. Temporary increases in illumination may be necessary for clinical evaluation or performing a procedure. It is important not to increase lighting levels for adjacent babies. Intense light may be harmful to the developing retina. It is best to permanently mount a procedure light than to have a free-standing floor light, so that space can be maximized and accidents avoided.

Oral Candidiasis In Children

Oral thrush, or oral pseudomembranous candidiasis, is a superficial mucous membrane infection that affects approximately 2–5% of normal newborns. Infants acquire Candida from their mothers at delivery and remain colonized.

Thrush may develop as early as 7–10 days of age. The use of antibiotics, especially in the 1st year of life, may lead to recurrent or persistent thrush. The plaques of thrush invade the mucosa superficially and may be found on the lips, buccal mucosa, tongue, and palate. Removal of plaques from these surfaces may cause mild punctate areas of bleeding, which helps to confirm the diagnosis.

Thrush may be asymptomatic or may cause pain, fussiness, and decreased feeding. It is uncommon after 12 months of age but may occur in older children treated with antibiotics. Persistent or recurrent thrush with no obvious predisposing reason, such as recent antibiotic treatment, warrants investigation of an underlying condition such as diabetes mellitus or immunodeficiency, especially vertically transmitted HIV infection.

Treatment:
Treatment of mild cases may not be necessary.

Pathophysiology of Cystic Fibrosis

Cystic fibrosis (CF) is an inherited multisystem disorder of children and adults, characterized chiefly by obstruction and infection of airways and by maldigestion and its consequences.

CF is inherited as an autosomal recessive trait. The CF gene codes for a protein of 1,480 amino acids called the CF transmembrane regulator (CFTR).

Four long-standing observations are of fundamental pathophysiologic importance:

1. failure to clear mucous secretions,
2. a paucity of water in mucous secretions,
3. an elevated salt content of sweat and other serous secretions, and
4. chronic infection limited to the respiratory tract

In addition, there is a greater negative potential difference across the respiratory epithelia of CF patients than across the respiratory epithelia of control subjects. Aberrant electrical properties were also demonstrated for CF sweat gland duct epithelium. The membranes of CF epithelial cells are unable to secrete chloride ions in response to cyclic adenosine monophosphate (cAMP)–mediated signals and, at least in the respiratory tract, excessive amounts of sodium are absorbed through these membranes.

Cyclic AMP-stimulated chloride conductance is a function of CFTR itself; this function is absent in epithelial cells with many different mutations of the CFTR gene.

The postulated epithelial pathophysiology in airways involves an inability to secrete salt and secondarily to secrete water in the presence of excessive reabsorption of salt and water. The proposed outcome is insufficient water on the airway surface to hydrate secretions. Desiccated secretions become more viscous and elastic (rubbery) and are harder to clear by mucociliary and other mechanisms.These secretions are retained and obstruct airways, starting with those of the smallest caliber, the bronchioles. Airflow obstruction at the level of small airways is the earliest observable physiologic abnormality of the respiratory system.

Atrial Septal Defect

Introduction:
Atrial septal defects (ASDs) can occur in any portion of the atrial septum (secundum, primum, or sinus venosus), depending on which embryonic septal structure has failed to develop normally. Less commonly, the atrial septum may be nearly absent, with the creation of a functional single atrium. Isolated secundum ASDs account for ?7% of congenital heart defects.

The majority of cases of ASD are sporadic; autosomal dominant inheritance does occur as part of the Holt-Oram syndrome (hypoplastic or absent radii, 1st-degree heart block, ASD) or in families with secundum ASD and heart block.

Pathophysiology:
An isolated valve-incompetent patent foramen ovale (PFO) is a common echocardiographic finding during infancy. It is usually of no hemodynamic significance and is not considered an ASD; a PFO may play an important role if other structural heart defects are present. If another cardiac anomaly is causing increased right atrial pressure (pulmonary stenosis or atresia, tricuspid valve abnormalities, right ventricular dysfunction), venous blood may shunt across the PFO into the left atrium with resultant cyanosis. Because of the anatomic structure of the PFO, left-to-right shunting is unusual outside the immediate newborn period. In the presence of a large volume load or a hypertensive left atrium (secondary to mitral stenosis), the foramen ovale may be sufficiently dilated to result in a significant atrial left-to-right shunt. A valve-competent but probe-patent foramen ovale may be present in 15–30% of adults. An isolated PFO does not require surgical treatment, although it may be a risk for paradoxical (right to left) systemic embolization.

Neonatal Cold Injury

Neonatal cold injury usually occurs in abandoned infants or those in inadequately heated homes during damp cold spells when the outside temperature is in the freezing range .

Clinical Features:
The initial features are apathy, refusal of food, oliguria, and coldness to touch. The body temperature is usually between 29.5 and 35°C (85–95°F), and immobility, edema, and redness of the extremities, especially the hands, feet, and face, are observed. Bradycardia and apnea may also occur. The facial erythema frequently gives a false impression of health and delays recognition that the infant is ill. Local hardening over areas of edema may lead to confusion with scleredema. Rhinitis is common, as are hypoglycemia and acidosis. Hemorrhagic manifestations are frequent; massive pulmonary hemorrhage is a common finding at autopsy.

Treatment :
Consists of warming and paying scrupulous attention to recognizing and correcting hypotension and metabolic imbalances, particularly hypoglycemia.

Enterobius Vermicularis Infection in Children

ETIOLOGY.
The cause of enterobiasis, or pinworm infection, is Enterobius vermicularis,which is a small (1 cm in length), white, threadlike nematode, or roundworm, that typically inhabits the cecum, appendix, and adjacent areas of the ileum and ascending colon. Gravid females migrate at night to the perianal and perineal regions, where they deposit up to 15,000 eggs.Eggs embryonate within 6 hr and remain viable for 20 days.

MODE OF INFECTION.
Human infection occurs by the fecal-oral route typically by ingestion of embryonated eggs that are carried on fingernails, clothing, bedding, or house dust. After ingestion, the larvae mature to form adult worms in 36–53 days.

PATHOGENESIS.
Enterobius infection may cause symptoms by mechanical stimulation and irritation, allergic reactions, and migration of the worms to anatomic sites where they become pathogenic.

CLINICAL MANIFESTATIONS.
Pinworm infection is innocuous and rarely causes serious medical problems. The most common complaints include itching and restless sleep secondary to nocturnal perianal or perineal pruritus. The precise cause and incidence of pruritus are unknown. They may be related to the intensity of infection, psychologic profile of the infected individual and his or her family, or allergic reactions to the parasite.

Nail Separation

Onycholysis indicates separation of the nail plate from the distal nail bed.

Common causes are 

• trauma, 
• chronic exposure to moisture, 
• hyperhidrosis, 
• cosmetics, 
• psoriasis, 
• fungal infection (distal onycholysis), 
• atopic or contact dermatitis, 
• porphyria, 
• drugs (bleomycin, vincristine, retinoid agents, indomethacin, chlorpromazine [Thorazine]), and 
• drug-induced phototoxicity from tetracyclines or chloramphenicol.

Beau lines are transverse grooves in the nail plate that represent a temporary disruption of formation of the nail plate. The lines 1st appear a few weeks after the event that caused the disruption in nail growth. A single transverse ridge appears at the proximal nail fold in most 4–6 wk old infants and works its way distally as the nail grows; this line may reflect metabolic changes after delivery.

Clinical Manifestations of Congenital Hypopituitarism.

The child with hypopituitarism is usually of normal size and weight at birth although those with MPHD and genetic defects of the GH1 or GHR gene have birth lengths that average 1 SD below the mean. Children with severe defects in GH production or action are more than 4 SD below the mean by 1 yr of age. Those with less severe deficiencies grow at rates below the 25% for age and gradually diverge from normal height percentiles. Delayed closure of the epiphyses permits growth beyond the normal age when growth should be complete.

Infants with congenital defects of the pituitary or hypothalamus usually present with neonatal emergencies such as apnea, cyanosis, or severe hypoglycemia with or without seizures.

Microphallus in boys provides an additional diagnostic clue.

Deficiency of GH may be accompanied by hypoadrenalism and hypothyroidism.

Prolonged neonatal jaundice is common. It involves elevation of conjugated and unconjugated bilirubin and may be mistaken for neonatal hepatitis.

The head in the toddler is round, and the face is short and broad. The frontal bone is prominent, and the bridge of the nose is depressed and saddle-shaped. The nose is small, and the nasolabial folds are well developed. The eyes are somewhat bulging. The mandible and the chin are underdeveloped, and the teeth, which erupt late, are frequently crowded. The neck is short, and the larynx is small. The voice is high-pitched and remains high after puberty. The extremities are well proportioned, with small hands and feet. Weight for height is usually normal, but an excess of body fat and a deficiency of muscle mass contributes to a pudgy appearance.

Clinical Manifestations of Acquired Hypopituitarism

The child initially is normal; manifestations similar to those seen in idiopathic pituitary growth failure gradually appear and progress.

When complete or almost complete destruction of the pituitary gland occurs, signs of pituitary insufficiency are present.

Atrophy of the adrenal cortex, thyroid, and gonads results in loss of weight, asthenia, sensitivity to cold, mental torpor, and absence of sweating.

Sexual maturation fails to take place or regresses if already present. There may be atrophy of the gonads and genital tract with amenorrhea and loss of pubic and axillary hair.

There is a tendency to hypoglycemia. Growth slows dramatically. Diabetes insipidus may be present early but tends to improve spontaneously as the anterior pituitary is progressively destroyed.

Clinical Features of Cystic Fibrosis

The clinical features of cystic fibrosis are summarized below:

Respiratory Tract.Cough is the most constant symptom of pulmonary involvement. At first, the cough may be dry and hacking, but eventually it becomes loose and productive. In older patients, the cough is most prominent on arising in the morning or after activity. Expectorated mucus is usually purulent. Some patients remain asymptomatic for long periods or seem to have prolonged but intermittent acute respiratory infections. Others acquire a chronic cough in the 1st weeks of life, or they have pneumonia repeatedly.

Extensive bronchiolitis is attended by wheezing, which is a frequent symptom during the 1st years of life. As lung disease slowly progresses, exercise intolerance, shortness of breath, and failure to gain weight or grow are noted. Exacerbations of lung symptoms, presumably owing to more active airways infection, eventually require repeated hospitalizations for effective treatment.

Cor pulmonale, respiratory failure, and death eventually supervene unless lung transplantation is accomplished. Colonization with Burkholderia cepacia and other multidrug-resistant organisms may be associated with particularly rapid pulmonary deterioration and death.

Early physical findings include increased anteroposterior diameter of the chest, generalized hyperresonance, scattered or localized coarse crackles, and digital clubbing. Expiratory wheezes may be heard, especially in young children.

Even though the paranasal sinuses are virtually always opacified radiographically, acute sinusitis is infrequent. Nasal obstruction and rhinorrhea are common, caused by inflamed, swollen mucous membranes or, in some cases, nasal polyposis. Nasal polyps are most troublesome between 5 and 20 yr of age.

Endocardial Cushion Defect - Pathophysiology, Clinical findings And Management

Pathophysiology
– When both ASDs and VSDs occur, which are contiguous, and the atrioventricular valves are abnormal
Left-to-right shunt at both atrial and ventricular levels; some right-to-left shunting with desaturation (mild, intermittent cyanosis)
Atrioventricular valve insufficiency –+ increase volume load on one or both ventricles; early heart failure, infections, minimal cyanosis, hepatomegaly, and failure to thrive.

Physical examination
Heart failure early in infancy (hepatomegaly, failure to thrive)
Eisenmenger physiology occurs earlier
– Moderate-to-severe increase in heart size with hyperdynamic precordium (precordial bulge and lift)
– Loud S1 widely fixed split S2 (like an isolated ASD)
Pulmonary systolic ejection murmur, low-pitched diastolic rumble at left sternal border and apex; may also have mitral insufficiency (apical harsh holosystolic murmur radiating to left axilla).

Clinical Features of Diseases Caused by Shigella

Bacillary dysentery is clinically similar regardless of infecting serotype; however, there are some clinical differences, particularly relating to the greater severity and risk for complications with S. dysenteriaeserotype 1 infection.

Incubation Period:
Ingestion of shigellae is followed by an incubation period of 12 hr to several days before symptoms ensue.

Clinical Manifestations:
Severe abdominal pain, high fever, emesis, anorexia, generalized toxicity, urgency, and painful defecation characteristically occur. Physical examination at this point may show abdominal distention and tenderness, hyperactive bowel sounds, and a tender rectum on digital examination.

The diarrhea may be watery and of large volume initially, evolving into frequent small-volume, bloody mucoid stools; most children (>50%) never progress to the stage of bloody diarrhea, whereas in others the 1st stools are bloody. Significant dehydration related to the fluid and electrolyte losses in both feces and emesis can occur. Untreated diarrhea may last 1–2 wk; only about 10% of patients have diarrhea persisting for more than 10 days.

Neurologic findings are among the most common extraintestinal manifestations of bacillary dysentery, occurring in as many as 40% of hospitalized infected children. Enteroinvasive E. coli can cause similar neurologic toxicity. Convulsions, headache, lethargy, confusion, nuchal rigidity, or hallucinations may be present before or after the onset of diarrhea. The cause of these neurologic findings is not understood.

Clinical Features of Infectious Mononucleosis

Incubation Period:
The incubation period of infectious mononucleosis in adolescents is 30–50 days. In children, it may be shorter. The majority of cases of primary EBV infection in infants and young children are clinically silent. In older patients, the onset of illness is usually insidious and vague.

Prodrome of Illness:
Patients may complain of malaise, fatigue, acute or prolonged (>1 wk) fever, headache, sore throat, nausea, abdominal pain, and myalgia. This prodromal period may last 1–2 wk. The complaints of sore throat and fever gradually increase until patients seek medical care. Splenic enlargement may be rapid enough to cause left upper quadrant abdominal discomfort and tenderness, which may be the presenting complaint.

Physical Examination:
The physical examination is characterized by generalized lymphadenopathy (90% of cases), splenomegaly (50% of cases), and hepatomegaly (10% of cases).

Lymphadenopathy occurs most commonly in the anterior and posterior cervical nodes and the submandibular lymph nodes and less commonly in the axillary and inguinal lymph nodes. Epitrochlear lymphadenopathy is particularly suggestive of infectious mononucleosis.

Symptomatic hepatitis or jaundice is uncommon, but elevated liver enzymes are common.

Splenomegaly to 2–3 cm below the costal margin is typical; massive enlargement is uncommon.

Diagnosis of Infectious Mononucleosis

The diagnosis of infectious mononucleosis implies primary EBV infection.

A presumptive diagnosis may be made by the presence of typical clinical symptoms with atypical lymphocytosis in the peripheral blood. The diagnosis is usually confirmed by serologic testing, either for heterophile antibody or specific EBV antibodies.

Culture of EBV is tedious and requires 4–6 wk. The culture method is the transformation assay, which is performed by co-cultivating oropharyngeal or genital secretions, peripheral blood (10–30 mL), or tumor with human umbilical cord lymphocytes. The cultures are observed for 6 wk for signs of cell transformation: proliferation and rapid growth, mitotic figures, large vacuoles, granular morphology, and cell aggregation. EBV immortalizes the umbilical cord cells, resulting in cell lines that can be maintained in perpetuity that harbor EBV isolated from the patient.

In >90% of cases there is leukocytosis of 10,000–20,000 cells/mm3, of which at least ? are lymphocytes; atypical lymphocytes usually account for 20–40% of the total number. The atypical cells are mature T lymphocytes that have been antigenically activated. Compared with regular lymphocytes microscopically, atypical lymphocytes are larger overall, with larger, eccentrically placed indented and folded nuclei with a lower nuclear-to-cytoplasm ratio. Although atypical lymphocytosis may be seen with many of the infections usually causing lymphocytosis, the highest degree of atypical lymphocytes is classically seen with EBV infection.

Heterophile antibodies agglutinate cells from species different from those in the source serum. The transient heterophile antibodies seen in infectious mononucleosis, also known as Paul-Bunnell antibodies, are IgM antibodies detected by the Paul-Bunnell-Davidsohn test for sheep red cell agglutination. The heterophile antibodies of infectious mononucleosis agglutinate sheep or, for greater sensitivity, horse red cells but not guinea pig kidney cells.

Scurvy in Children

Very low intake of vitamin C over time may lead to the deficiency disease scurvy.

Age of Onset:
In infants and young children, the usual age of onset of clinical manifestations of scurvy is 6–24 months.

Early Symptoms:
The early symptoms are rather general and include low-grade fever, irritability, tachypnea, digestive disturbances, loss of appetite, and generalized tenderness, particularly in the legs, which is noticeable when the diaper is changed. The pain results in pseudoparalysis, with the hips and knees semi-flexed and the feet rotated outward.

Other Clinical Features:
Edematous swelling along the shafts of the legs may be present; in some cases, there is subperiosteal hemorrhage at the end of the femur .

A “rosary” at the costochondral junctions and depression of the sternum are other typical features.

Changes in the gums are most noticeable after teeth have erupted and are manifested as bluish purple, spongy swellings of the mucous membrane, especially over the upper incisors.

Anemia, which is seen primarily in infants and young children, may be related to impaired ability to use iron or folate.

Other clinical manifestations seen in infants as well as in older children and adolescents include swollen joints, purpura and ecchymoses, poor wound and fracture healing, petechiae, perifollicular hemorrhages , hyperkeratosis of hair follicles, arthralgia, and muscle weakness. Endochondral bone formation may not proceed because osteoblasts cannot form osteoid. Bony trabeculae that have been formed become brittle and fracture easily. Irritability and other psychologic manifestations are likely due to impaired neurotransmitter metabolism.

Brain Abscess In Children

Brain abscesses can occur in children of any age but are most common in children between 4 and 8 yr and neonates.

CAUSES.
The causes of brain abscess include embolization due to congenital heart disease with right-to-left shunts (especially tetralogy of Fallot), meningitis, chronic otitis media and mastoiditis, sinusitis, soft tissue infection of the face or scalp, orbital cellulitis, dental infections, penetrating head injuries, immunodeficiency states, and infection of ventriculoperitoneal shunts.

PATHOLOGY.
Cerebral abscesses are evenly distributed between the two hemispheres, and aapx. 80% of cases are divided equally between the frontal, parietal, and temporal lobes.. An abscess in the frontal lobe is often caused by extension from sinusitis or orbital cellulitis, whereas abscesses located in the temporal lobe or cerebellum are frequently associated with chronic otitis media and mastoiditis.

ETIOLOGY.
The responsible bacteria include streptococci (S. milleri, S. pyogenes group A or B, S. pneumoniae, S. faecalis), anaerobic organisms (gram-positive cocci, Bacteroides spp., Fusobacterium spp., Prevotella spp., Actinomyces spp.), and gram-negative aerobic bacilli (Haemophilus aphrophilus, H. parainfluenzae, H. influenzae, Enterobacter, E. coli, Proteus spp.). Citrobacter is most common in neonates. One organism is cultured in the majority of abscesses (70%), two in 20%, and three or more in 10% of cases. Abscesses associated with mucosal infections (sinusitis) frequently have anaerobic bacteria.

Treatment of Iron Deficiency Anemia

The regular response of iron-deficiency anemia to adequate amounts of iron is an important diagnostic and therapeutic feature.

Oral Iron:
Oral administration of simple ferrous salts (e.g., sulfate, gluconate, fumarate) provides inexpensive and satisfactory therapy. No evidence shows that addition of any trace metal, vitamin, or other hematinic substance significantly increases the response to simple ferrous salts. One problem encountered with administration of oral iron to young children is that liquid FeSO4nhas an unpleasant taste, but sometimes the taste can be camouflaged by mixing with flavored syrup. Other, better-tasting preparations are available over the counter, but these are much more expensive than simple liquid FeSO4. Aside from the unpleasant taste, intolerance to oral iron is uncommon in young children, although older children and adolescents sometimes have gastrointestinal complaints. Problems with constipation can be minimized by increasing water and fiber intake. For some children, abdominal discomfort can be minimized by administering iron with food, recognizing that this may decrease iron absorption to some extent.

The therapeutic dose should be calculated in terms of elemental iron; ferrous sulfate is 20% elemental iron by weight. A daily total dose of 4–6 mg/kg of elemental iron in 3 divided doses provides an optimal amount of iron for the stimulated bone marrow to use.

Myocarditis

Myocarditis refers to inflammation, necrosis, or myocytolysis and may be caused by many infectious, connective tissue, granulomatous, toxic, or idiopathic processes affecting the myocardium with or without associated systemic manifestations of the disease process or involvement of the endocardium or pericardium.

Etiology:
The most common causative agents in children are adenovirus, coxsackievirus B, and other enteroviruses, although most known viral agents have been implicated.

Pathophysiology:
Acute viral myocarditis may produce a fulminant inflammatory process characterized by cellular infiltrates, cell degeneration and necrosis, and subsequent fibrosis. Viral myocarditis may also become a chronic process with persistence of viral RNA or DNA (but not infectious virus particles) in the myocardium.In addition, some viral proteins may share antigenic epitopes with host cells, which results in autoimmune damage to the antigenically related myocyte.

The net final result of chronic viral-associated inflammation is often dilated cardiomyopathy.

Clinical Manifestations:
Signs and symptoms depend on the patient’s age and the acute or chronic nature of the infection. A neonate may initially have fever, severe heart failure, respiratory distress, cyanosis, distant heart sounds, weak pulses, tachycardia out of proportion to the fever, mitral insufficiency caused by dilatation of the valve annulus, a gallop rhythm, acidosis, and shock. Evidence of viral hepatitis, aseptic meningitis, and an associated rash may be present. In the most fulminant form, death may occur within 1–7 days of the onset of symptoms.

Treatment of Pneumothorax

Therapy varies with the extent of the collapse and the nature and severity of the underlying disease.

A tension pneumothorax may emergently require drainage by needle thoracostomy. A small or even moderate-sized pneumothorax in an otherwise normal child may resolve without specific treatment, usually within about 1 wk. A small (<5%) pneumothorax complicating asthma may also resolve spontaneously.

Administering 100% oxygen may hasten resolution. Patients with chronic hypoxemia should be monitored closely during the administration of supplemental oxygen. Pleural pain deserves analgesic treatment. If there is >5% collapse or if the pneumothorax is recurrent or under tension, chest tube drainage is necessary.

Pneumothoraces complicating Cystic fibrosis frequently recur, and definitive treatment may be justified with the 1st episode, even with <5% collapse.

Closed thoracotomy (simple insertion of a chest tube) and drainage of the trapped air through a catheter, the external opening of which is kept in a dependent position under water, is adequate to re-expand the lung in most patients; pigtail catheters are frequently used.

When there have been previous pneumothoraces, it may be indicated to induce the formation of strong adhesions between the lung and chest wall by a sclerosing procedure to prevent recurrence. This can be carried out by the introduction of doxycycline or talc into the pleural space (chemical pleurodesis).

Clinical Manifestations of Osteogenesis Imperfecta

Osteogenesis imperfecta has the triad of fragile bones, blue sclerae, and early deafness. OI was once divided into “congenita,” the forms detectable at birth, and “tarda,” the forms detectable later in childhood; this did not account for the variability of OI.

The Sillence classification divides OI into four types based on clinical and radiographic criteria. Additional types have been proposed based on histologic distinctions.

Osteogenesis Imperfecta Type I (Mild):
This form is sufficiently mild that it is often found in large pedigrees. Many type I families have blue sclerae, recurrent fractures in childhood, and presenile hearing loss (30–60%). Both types I and IV are divided into A and B subtypes, depending on the absence (A) or presence (B) of dentinogenesis imperfecta. Other possible connective tissue abnormalities include easy bruising, joint laxity, and mild short stature compared with family members. Fractures result from mild to moderate trauma and decrease after puberty.

Osteogenesis Imperfecta Type II (Perinatal Lethal):
These infants may be stillborn or die in the 1st yr of life. Birthweight and length are small for gestational age. There is extreme fragility of the skeleton and other connective tissues. There are multiple intrauterine fractures of long bones, which have a crumpled appearance on radiographs. There are striking micromelia and bowing of extremities; the legs are held abducted at right angles to the body in the “frog-leg position.” Multiple rib fractures create a beaded appearance and the small thorax contributes to respiratory insufficiency. The skull is large for body size with enlarged anterior and posterior fontanelles. Sclerae are dark blue-gray