Top 3 Differentials - Paeds Flashcards
(26 cards)
Neonatal lung disease with diffuse granular opacities
Top 3 DDx:
- Surfactant deficiency
- Transient tachypnoea of newborn (TTN)
- Neonatal pneumonia
Surfactant deficiency Commonest cause or resp distress in preterm, esp <34 weeks or <1500g. Immature lungs unable to produce surfactant enough to keep alveoli open.
Grunting, nasal flaring, subcostal retractions, tachypneoa, cyanosis.
CXR shows diffusely hazy and low lung volumes, with air bronchograms.
Severe cases need assisted ventilation, along with surfactant therapy, with well airated lungs on intubation, but potential complications like PIE, pneumomediastinum and pnemothorax, or bronchopulmonary dysplasia in chronic ventilation.
TTN Commonest neonatel respiratory distress. Transient and benign.
Immature lymphatics cannot absorb residual lung fluid, made worse with C-section due to absent vaginal squeeze clearing lungs.
Clinical and CXR improvement in 48 and 72 hrs.
CXR shows streaky central opacities and small pleural effusions. More severe cases show pulmonary vascular congestion and airspace opacities.
Lung volumes are normal to increased. Rx is supportive.
Neonatal pneumonia Bacterial pneumonias, especially group B strep. Commonly with early rupture of membranes, spread during birth.
CXR shows diffuse haziness and granularity, mimicing surfactant deficiency, but with pleural effusions. Can be complicated with empyema, pulmonary abscess and pneumatocele.
Neonatal lung disease with low lung volumes
Top 3 DDx:
- Surfactant deficiency
- Beta-haemolytic strep pneumonia (Group B Strep, GBS)
- Pulmonary hypoplasia
Surfactant deficiency Commonest cause of resp distress in preterm. Immaturity of the lungs and inability to produce enough surfactant to keep alveoli open.
Resp distress (grunting, nasal flaring, subcostal retractions, tachypneoa, cyanosis) seen shortly after delivery. Most will be apparent within 8 hours.
Normal CXR at 8hrs excludes this diagnosis.
CXR shows diffusely hazy, underaerated lungs with peripherally extending air bronchograms (atelectasis).
Granularity and reticularity result from diffuse alveolar collapse.
In severe cases, assisted ventilation may be needed in addition to surfactant replacement.
Ventilation causes PIE, pneumonediastinum and pneumothorax, as well as BPD in long term.
GBS Bacterial pneumonias, esp GBS, are most common in this age. Usually due to infection after premature rupture of membranes.
Clinically: respiratory distress shortly after birth.
CXR shows diffuse haziness and granularity, however lung volumes can be normal to expanded, due to exudate filled, distended alveoli. GBS generally low volumes, other organisms high. Pleural effusions are also seen, rarely seen in surfactant deficiency.
Complications include empyema, pulmonary abscess and pneumatocele.
Pulmonary hyperplasia Bilateral pulmonary hypoplasia is due to a number of causes, including pulmonary compression from oligohydramnios, thoracic dystrophies and intrathoracic herniation of abdominal viscera.
Potter syndrome - pulmonary hypoplasia secondary to renal agenesis and resultant oligohydramnios.
Clinically - respiratory distress shortly after birth. Lungs generally clear on CXR, just small.
Pneumothorax and pneumomediastinum can occur with ventilation, or spontaneously due to neonates own effort to inflate hypoplastic lungs.
Neonatal lung disease with increased lung volumes
Top 3 DDx:
- Transient tachypnoea of the newborn (TTN)
- Meconium aspiration
- Neonatal pneumonia
Other DDx:
- Congenital heart disease
TTN Acute resp distres in term babies, often with C-sections. Lack of vaginal squeeze causes retained foetal lung fluid, slow to be cleared by immature lymphatics.
CXR shows hyperinflation with b/l diffuse patchy airspace disease and normal heart size.
Perihilar linear densities, pleural effusions and fluid in fissues also seen.
Air space disease similar to pulmonary oedema, usually clears in 3 days.
Clinical course is mild and if persistent, other diagnoses should be considered.
Meconium aspiration Postterm neonates with in utero or peripartum distress.
Aspirated meconium causes chemical pneumonitis, with moderate to severe resp distress.
Amniotic fluid is stained with meconium.
CXR shows hyperinflation, patchy airspace disease, pleural effusions and post obstructive atelectasis.
40% get pneumothorax.
Neonatal pneumonia Resp distress with focal or diffuse airspace disease and hyperinflation.
Lysteria, E.coli and klebsiella are common organisms. GBS causes low volumes.
CXR includes hyperinflation, patchy asymmetric hilar densities. Resolves over short time with correct antibiotics.
Congenital heart disease Resp distress, parenchymal opacities and hyperexpanded lungs. Abnormal mediastinal contour (e.g. cardiomegaly, pulmonary vascular congestion) and hyperinflation.
Acyanotic - think Shunt lesions, congestive heart failure. Cyanotic - transposition, truncus arteriosus, TAPVR, tricuspid atresia and single ventricle.
Cyanotic infant with decreased pulmonary flow
Top 3 DDx:
- Tetralogy of Fallot (TOF)
- Pulmonary atresia
- Tricuspid atresia
Other DDx:
- Double outlet right ventricle
- Ebstein anomaly
TOF Commonest cyanotic heard disease in kids.
Consists of RV outflow obstruction (pulmonary stenosis), VSD, Overriding aorta and RV hypertrophy.
Deficient right pulmonary artery and elevated cardiac apex due to RVH cause boot chaped heart on CXR.
Pulmonary vascularity decreased, varied severity. Arch on right in 25%.
Pulmonary atresia Underdevlopment of right ventricular outflow tract and pulmonary valve. Considered a severe variant of TOF when a VSD is also present, with similar imaging.
Without VSD, right-left shunt occurs at atrial level. Severe cardiomegaly is common, other imaging findings vary.
Normal to decreased pulmonary vascularity depending on PDA.
Tricuspid atresia No direct path for blood flow between right atrium and ventricle, so right to left shunt happens at atrial level via PFO.
Pulmonary blood flow depends on VSD and or PDA.
30% get associated anomalies inlcuding transposition.
Isolated tricuspid atresia with snall VSD, CXR shows normal heart size with decreased blood flow. Larger VSD causes cardiomegaly and increased pulmonary flow.
10% have right sided arch.
Double outlet right ventricle Aorta and PA arise from right ventricle. Some forms mimic TOF with pulmonary oligaemia and reduced left hilar shadow.
Ebstein anomaly Apical displacement of tricuspid valve, causing atrialisation of the right ventricle.
Tricuspid regurg with stasis of blood in right atrium, leads to massive right sided cardiomegaly and box shaped heart, and pulmonary oligaemia. Right to left shunt at atrial level is common.
Cyanotic infant with increased pulmonary vascularity
Top 3 DDx:
- Transposition of great arteries (TGA)
- Truncus arteriosus
- Total anomalous pulmonary venous return
Other DDx:
- Tricuspid atresia
- Single ventricle
TGA d-TGA - aorta from RV and PA from LV. PFO, VSD or PDA is needed to allow right to left communication, otherwise not compatible with life. CXR shows cardiomegaly (egg on string) and increased pulmonary vascularity - however this is rarely seen due to prompt treatment.
Truncus arteriosus Failure of division of single primitive truncal vessel into PA and Aorta.
Large high VSD always associated.
Pulmonary blood flow depends on pulmonary resistance. Resistance usually reduces by day 2-3 of life, with pulmonary blood flow increasing.
CXR shows cardiomegaly, right sided arch (30%) and increased pulmonary vascularity.
TAPVR All pulmonary veins drain intro right heart. 3 types depending on location of pulmonary veins. Supracardiac (commonest, snowman CXR) - enlarged SVC and left vertical vein, Cardiac - draining into coronary sinus and infracardiac - drain below diaphragm into portal veins or IVC.
Infracardiac associated with heterotaxy and presents with severe pulmonary oedema and normal heart size.
All 3 associated with PFO.
Tricuspid atresia No direct path from RA to RV, with right to left shunt at atrial level, usually through PFO.
Pulmonary blood flow depends on VSD or PDA. Large VSD causes cardiomegaly and increased pulmonary vascularity.
Single ventricle Absent interventricular septum. Patients without pulmonary stenosis demonstrate cardiomegaly, enlarged main PA and increased pulmonary blood flow.
Shunt vascularity
Top 3 DDx:
- VSD
- ASD
- PDA
Other DDx:
- Atrioventricular canal defect
VSD commonest acyanotic shint vascularity, second commonest congenital heart after bicuspid aortic valve.
CXR can be normal if defect is small. Larger defects cause cardiomegaly, increased number and size of well defined pulmonary vessels (shunt vascularity), enlarged PA and enlarged LA.
Pulmonary hyperinflation is also common.
Present around 6 weeks old with failure to thrive and murmur. Like other L to R shunts, if untreated, can cause severe pulmonary hypertension with reversal of flow across the shunt (Eisenmenger physiology).
ASD Radiographic findings may be absent with small ASDs. Larger ones cause mild cardiomegaly, normal-enlarged main PA and shunt vascularity. LA is not enlarged.
Relatively late presentation as less blood across the shunt. More often clinically occult, therefore more severe pulmonary HTN at presentation.
PDA Ductus arteriosus usually closes in immediate perinatal period. Failure to close causes shunted blood across ductus. Commonly seen in premature infants.
Causes cardiomegaly and varying degrees of shunt vascularity. Over time, left atrial and ventricular enlargement occur. PDA may be needed for survival if associated with other cardiac malformations.
Atrioventricular canal defect aka endocardial cushion defect. Failure of atrial and ventricular septum to fully form, with mitral and/or tricuspid valves abnormal too.
50% have Downs. Like other L to R shunts, CXR shows cardiomegaly, pulmonary artery enlargement and shunt vascularity.
Pulmonary mass
Top 3 DDx:
- Round pneumonia
- Congenital Pulmonary Airway Malformation (CPAM)
- Sequestration
Other DDx:
- Bronchogenic cyst
- Pleuropulmonary blastoma
Round pneumonia Well defined pulmonary opacity in kids up to 8YO, most often superior segment of lower lobe. Usually S. Pneumoniae.
Confined inflammatory process due to lack of developed collateral pathways. Follow-up CXR to ensure resolution.
CPAM Part of spectrum of bronchopulmonary foregut malformations.
Usually Dx in utero, older patients may get resp disress or recurrent pneumonia.
Abnormal proliferation of respiratory elements communicating with tracheobronchial tree. 3 types: 1 - Cysts >2cm, most common. 2 - Many smaller cysts, a/w congenital abnormalities. 3 - grossly solid but truly microcystic.
Solid mass in infants on CXR, solid or cystic in older children. CT shows air or fluid filled cysts or solid lesion depending on type.
Sequestration Consists of dysplastic and nonfunctioning lung tissue with systemic arterial supply. Connects with tracheobronchial tree when infected. Most often LLL.
Extralobar present early, with systemic venous drainage and it’s own pleural covering.
Intralobar presents later with recurring infections, pulmonary drainage and no pleural covering.
Both are solid mass unless areas of CPAM or infection, when tissue breakdown permits communication with bronchial tree.
Bronchogenic cyst Solitary, discrete mediastinal mass. May contain simple or complex fluid, thin walled. Can cause mass effect on mediastinal structures, leading to dysphagia, resp distress or chest pain in older kids.
Pleuropulmonary blastoma Rare, aggressive, primary pleural or parenchymal malignancy. >5cm cystic, solid or mixed soft tissue mass. Pleural effusion is common.
Liver mass in an infant
Top 3 DDx:
- Hepatoblastoma
- Haemangioendothelioma
- Mesenchymal hamartoma
Other DDx:
- Mets
- Abscess
- Haematoma
Hepatoblastoma Commonest primary hepatic neoplasm in infancy (usually <3YO).
Painless abdominal mass, elevated AFP.
Large, solitary, well defined heterogenous lesions, hypodense on CT, 50% are calcified. Chunky, coarse calcifications compared to finer calcs in haemangioendothelioma. SOlid parts enhance.
US shows heterogenous lesion with regions of calcification.
Haemangioendothelioma Vascular hepatic lesion in neonates, 90% in first 6 months. Cause high output cardiac failure when large.
Large, heterogenous, hypodense on CT, with fine calcifications and enhancement.
Vascular shunting may cause enlargement of suprahepatic aorta and decreased calibre of infrahepatic aorta.
Mesenchymal hamartoma Rare benign hepatic masses, in infants.
Well circumscribed, cystic, multiloculated. Solid components, if present, may resemble hepatoblastoma or haemangioendothelioma.
Mets Neuroblastoma mets, commonly heterogenous due to haemorrhage and calcification. Mets from Wilms are less common and hypodense on CT.
Abscess Hypodense with perioheral enhancement, due to haematogenous or direct spread of infection.
Haematoma Vary in size and appearance, due to underlying trauma.
Hypodense compared to surrounding liver, but be sure to exclude active extravasation of contrast. Should resolve over time.
Suprarenal mass in child
Top 3 DDx:
- Neuroblastoma
- Phaeochromocytoma
- Subdiaphragmatic sequestration
Other DDx:
- Adrenal haemorrhage
- Adrenocortical carcinoma
- Congenital adrenal hyperplasia (CAH)
Neuroblastoma Malignant neural crest tumour. 10% of childhood malignancies.
Average age of 2YO.
May present with paraneoplastic syndromes (profuse, watery diarrhoea). Usually arises in adrenals.
Infiltrative soft tissue mass, commonly calcifies, encases rather than invading vessels. Mets to liver and bone.
Phaeochromocytoma 70% in adrenal gland. Rare in kids. Present with HTN.
Most occur spontaneously, also a/w MEN and VHL.
MIBG avid, very T2 bright and large, heterogenous tumours on CT with avid solid enhancement and regions of necrosis or cystic change. <10% calcify.
Subdiaphragmatic sequestration Can occur below diaphragm, usually left suprarenal. Always extralobar.
Adrenal haemorrhage Significantly more common than neuroblastoma in perinatal period, but uncommon in older kids without trauma.
US shows hypo or anechoic, avascular suprarenal mass, although acute haemorrhage may appear complex.
CT shows adrenal haemorrhage hyperdense acutely, reducing with time.
Should get smaller over time and lead to calcification eventually.
Adrenocortical carcinoma Rare in childhood, more common than simple adenomas.
Usually hormonaly active.
Usually >5cm, with internal necrosis and calcification, causing irregular heterogenous appearance.
CAH Usually with underlying enzyme deficiency.
Imaging shows bilateral diffuse or nodular adrenal enlargement.
Solid renal mass in child
Top 3 DDx:
- Wilms
- Nephroblastomatosis
- Lymphoma
Other DDx:
- Mesoblastic nephroma
- RCC
Wilms Commonest renal malignancy of childhood, peaks at 3YO. Presents with abdominal mass.
Well defined, round mass from renal cortex, with local mass effect. Enhances less than surrounding renal parenchyma, and renal origin confirmed with claw sign (compressed renal parenchyma along tumour margin).
Larger ones are heterogenous, with cystic and necrotic parts and haemorrhage. Rarely calcifies or contains fat.
Spreads locally via renal vein, via lymphatics to local nodes, and haematogenously to bones, liver, lungs. A/w WAGR and Beckwith-Wiedemann syndromes.
Nephroblastomatosis Presence of nephrogenic rests. Present as bilateral, confluent, plaquelike or rounded, peripheral solid renal masses in infants.
Annual surveillance to exclude malignant degeneration into Wilms.
Lymphoma Secondary involvement is more common.
Multiple, bilateral homogenous hypodense parenchymal masses, or solitary renal mass or diffuse parenchymal infiltration.
Bulky adjacent lymphadenopathy also seen.
Mesoblastic nephroma Hamartoma of kidney, commonest solid renal mass in neonates (mean 2 months).
Asymptomatic except palpable mass.
Indistinguishable from Wilms on imaging, so Rx is surgical.
RCC Rare in kids, except VHL. Older kids with flank pain or haematuria.
Hypervascular renal mass, 25% calcify. RCC spreads locally via renal vein, lymphatics to local nodes, and haematogenously to liver, lungs, bones.
Toddler with stridor and airway narrowing
Top 3 DDx:
- Croup
- Epiglottitis
- Retropharyngeal abscess
Other DDx:
- Bacterial tracheitis
- Aspirated foreign body
- Haemangioma
Croup Commonest upper airway obstruction 6-36 months.
XR shows subglottic airway narrowing, loss of normal shouldering of upper airway on frontal (steeple sign). Lateral view confirms overdistension of hypopharynx and narrowed subglottic airway.
Epiglottitis Life threatening, older pts than croup. XR shows epiglottic enlargement (thumb sign) on lateral, and thick aryepiglottic folds. May mimic croup on frontal.
Retropharyngeal abscess May exert mass effect on airway, causing dyspnoea and stridor.
DDx of widened prevertebral soft tissues includes abscess, haemorrhage, lymphadenopathy, pseudothickening. If pseudothickening suspected, repeat inspiratory exam with neck fully extended may resolve.
Airway fluoroscopy may clarify difficult cases.
Bacterial tracheitis Exudative plaques adherent to tracheal walls, with flat longitudinal confuguration.
Asymmetric subglottic airway narrowing may resemble croup, however patients are older (6-10YO) and more toxic.
Adherent mucus in airway can mimic such plaques but will clear after coughing.
Aspirated foreign body Aspirated and ingested foreign bodies cause abnormal airway contours, and dyspnoea and stridor. Direct visualisation may ne needed for non-opaque objects. May show air trapping distal to it.
Haemangioma Variable asymmetric airway narrowing and commonly seen before 1YO. Subglottic ones can mimic symptoms of other causes of stridor. XR shows asymmetric mass effect narrowing the airway.
Unilateral cystic kidney
Top 3 DDx:
- Hydronephrosis
- Multicystic Dysplastic Kidney (MCDK)
- Multilocular cystic nephroma (MLCN)
Other DDx:
- Cystic wilms tumour
- ADPKD
- Renal abscess
Hydronephrosis Commonest cause of renal mass in kid.
Unilateral often due to UPJ obstruction or extrinsic ureteric compression.
B/L due to bladder outlet obstruction (Posterior urethral valves in boys).
US: Cystic lesions communicate with renal pelvis.
MCDK Intrauterine obstruction of fetal renal collecting system or altered induction of renal tissue due to abnormal UPJ.
US includes multiple cysts that do not communicate. Affected renal segment is non-functioning. Associated with contralateral abnormalities such as UPJ obstruction.
MLCN Rare, affecting young male children and older adult women. Multiloculated cystic renal mass herniating into renal pelvis.
Septations may enhance on CT. Surgically resected.
Cystic Wilms Large, heterogenous, solid abdominal mass usually, but can occasionally be cystic. Spreads locally (renal vein), lymphatically (local nodes) or haematogenously (lungs, liver, bones).
Can rarely involve both kidneys.
Invades vessels rather than encasing them (neuroblastoma).
Can be associated with cryptorchidism, hemihypertrophy, aniridia, Drash and other syndromes.
ADPKD Presents in late adolescence with hypertension or haematuria. Can be seen in infants.
Enlarged kidneys with multiple bilateral cortical and medullary cysts, pancreatic and liver cysts and 10% have intracranial berry aneurysms.
Renal abscess Rare, serious complications of UTI, occuring in kids with chronic infections usually from persistent VUR.
US shows ill defined hypoechoic region, usually at corticomedullary junction, with hypodensity on CT.
Bowel wall thickening in an immunocompromised child
Top 3 DDx:
- Pseudomembranous colitis
- Neutropenic colitis/typhilitis
- Graft-vs-host disease
Other DDx:
- Post transplant lymphoproliferative disorder
- Shock bowel
Pseudomembranous colitis Overgrowth of C/diff, occuring in those on Abx.
Colon wall thickened due to mucosal/submucosal oedema, affecting usually entire colon.
Accordion sign due to intraluminal fluid extending between pseudomembranes and oedematous haustra. Pericolonic fat is spared.
Neutropenic colitis/typhilitis Inflammatory, necrotising colitis of neutropenic kids, involves usually entire right colon, can be just caecum or include TI.
Commonest in acute leukaemia, with fever, diarhoea and tenderness.
Circumferencial, symmetric thickening, hypodense on CT and heterogenously enhancing, with pericolic stranding and sonetimes intramural pneumatosis.
Contrast enema contraindicated due to perf risk.
GVHD Marrow T cells damage recipient epithelial cells. Diarrhowa, hepatomegaly, ascites, and abdominal distension.
Mucosal ulceration and destruction, then replacement of mucosa with vascular granulation tissue.
CT shows intense mucosal enhancement, dilatation of entire small and large bowel. Follow through shows contrast filled ‘ribbon like’ bowel.
Rx: Immunosuppression.
PTLD Ranges from Lymphoid hyperplasia to malignant proliferation, associated with EBV reactivation.
Occurs in organ transplant recipients.
Circumferencial bowel wall thickening, sometimes aneurysmal dilatation. Lymphadenopathy, solid masses and hepatosplenomegaly may also occur.
Shock bowel aka hypoperfusion complex. Diffuse bowel wall thickening and enhancement, along with abnormal solid organ enhancement. Bowel enhancement similar to GCHD but this occurs with major trauma and usually spares large bowel.
Distal bowel obstruction in neonate
Top 3 DDx:
- Functional imaturity of the colon
- Hirschprung disease (HD)
- Ileal atresia/stenosis
Other DDx:
- Meconium ileus
- Anal atresia-anorectal malformations
Functional immaturity of the colon Includes small left colon and meconium plug syndromes.
Common, associated with prematurity, maternal magnesium or opiate use and diabetic mothers.
Failure to pass meconium, abdominal distension or vomiting.
AXR shows diffuse bowel distension. Contrast enema defines normal rectum and meconium plug in rectosigmoid colon.
Left colon may be small distal to splenic flexure. No organic obstruction seen.
After enema stimulates passage of meconium, bowels work normally.
HD Failure of migration of intramural ganglion cells. Aganglionic segment cannot relax, causing distal obstruction.
Presents with constipation, distension and or bilious vomiting. A/w Down’s.
XR shows distal obstruction and contrast enema shows dilated proximal colon, usually up to rectosigmoid junction.
Can rarely affect whole colon (lead pipe). Suction biopsy confirms lack of ganglion cells.
Ileal atresia/stenosis Due to intrauterine ischaemic injury. Presents with low bowel obstruction. Contrast enema defines normally positioned microcolon, due to colonic non use.
Meconium ileus Can be first sign of CF. Meconium blocks TI and right colon, causing obstruction.
XR shows lack of fluid-fluid levels, and soap bubble appearance of right lower quadrant.
Contrast enema defines pellets of meconium in distal ileum and right colon, and small microcolon.
Diagnostic water soluble enema may also allow meconium pellets to pass.
Anal atresia - anorectal malformation Usually clinically evident. Important to evaluate for associated renal and spinal cord abnormalities, and differentiate between high and low atresias.
Skeletal dysplasia
Top 3 DDx:
- Achondroplasia
- Thanatophoric dysplaisa
- Jeune syndroma
Other DDx:
- Ellis-van Cerveld syndrome
- Chondrodysplasia punctata
Achondroplasia Commonest non-lethal dysplasia, AD/ Skeletal abnormalities due to decreased cartilage matric production and endochondral ossification.
Rhizomelic (proximal) limb shortening, metaphyseal flaring and secreased interpediculate distance within lower lumbar spine are common.
Short iliac bones, decreased acetabular angles (tombstone pelvis) and inner pelvic contour has Champagne glass configuration.
Small skull base and foramen magnum cause brainstem compression.
Spina nomalies cause varying degrees of spinal stenosis.
Hypochondroplasia is less severe, findings are mild and often limited to spine.
Thanatophoric dysplasia Commonest lethal skeletal dysplasia.
Rhizomelic limb shortening, short ribs and narrow thorax - poor ventilation, platyspondyly, small iliac bones.
Abnormal bowing and shortening of femurs causes telephone receiver apearance. Fatal in neonatal period.
Jeune syndrome aka asphyxiating thoracic dysplasia, long bell shaped thorax with short horizontal ribs and flaired anterior ends.
Causes early respiratory compromise.
Dysplastic acetabuli cause upside down trident appearance.
Associated acromelic (distal) limb shortening.
Ellis-van-creveld syndrome Hair, nail and teeth abnormalities. X-ray shows acromelic limb shortening, short ribs, cone shaped epiphyses and postaxial polydactyly.
Congenital heart disease is major cause of morbidity.
Chondrodysplasia punctata Rhizomelic limb shortening and multifocal stippling in epiphyses, apophyses and spine.
Double bubble sign
Top 3 DDx:
- Malrotation/midgut volvulus
- Duodenal atresia/stenosis
- Annular pancreas
Other DDx:
- Duodenal web
- Preduodenal portal vein
Midgut volvulus Surgical emergency, bowel twists around mesenteric pedicle, associated with underlying malrotation.
Presents as bilious vomiting in infant, which normal to complete duodenal obstruction (mimics atresia) on imaging.
Upper GI examination needed to establish course of duodenum and proximal small bowel.
In setting of malrotation, duodenal-jejunal junction fails to cross midline and sits inferior to pylorus.
Proximal bowel demonstrates corkscrew appearance in volvulus.
Duodenal atresia/stenosis Both due to failure of recanalisation of duodenum, either partial or fully (atresia).
X-ray shows double bubble sign, with no distal gas in complete atresia. Presents with vomiting in first few hours, 80% bilious if obstruction is distal to ampulla.
Increased incidence in downs.
Annular pancreas Often coexists with duodenal atresia or stenosis. Presents in infancy with duodenal obstruction, or in adults with pancreatitis.
CT shows soft tissue mass continuous with pancreas, encircling duodenum.
UGI shows circumferencial narrowing of D2.
Duodenal web Intraluminal webs cause varying degrees of obstruction, presenting as older children or even adults.
Severe obstruction can present in infancy. Radiographicaly similar to other forms of duodenal obstruction.
UGI may show circumferencial narrowing of duodenum, or variable sized aperture allowing restricted amount of contrast to pass distally.
Web may stretch over time to cause windsock appearance.
Preduodenal portal vein Preduodenal portal vein may obstruct the duodenum, often a/w malrotation or other abnormalities.
Posterior vertebral body scalloping
Top 3 DDx:
- Dural ectasia
- Mucopolysaccharisosis (MPS)
- Skeletal dysplasia/achondroplasia
Other DDx:
- Spinal tumour
- Normal variant
Dural ectasia Enlargement or widening of dural sac. Due to connective tissue disorders (Marfans, Ehlers Danlos) and NF1.
Weakened dura transmits pressure on posterior aspect of vertebral body, causing scalloping.
NF-1 - masses like neurofibromas and thoracic meningoceles also cause posterior scalloping.
Marfan and EDS are prone to connective tissue abnormalities elsewhere, such as aneurysms.
NF-1 causes cutaneous and neurological manifestations.
MPS Inherited disorders of excessive deopisition of lysosomal glycosaminoglycans.
Short stature, craniofacial abnormalities and some cases mental retardation.
Hurler and Morquio are common variants.
Both cause diffuse posterior scalloping. Hurlers also causes anterior beaking of inferior aspect, while Morquio have anterior midportion beaking. Hurlers also gets enlarged J shaped sella.
Skeletal dysplasia/achondroplasia X-ray findings include large skull with narrow foramen magnum, spinal stenosis, squared iliac wings, progressively decreasing interpedicular distance in lumbar spine, flat acetabuli, short metacarpals and short ribs.
Posterior vertebral body scalloping is common and due to an adaptive response to spinal stenosis. Posterior scalloping also associated with metatropic dwarfism and OI.
Spinal tumour Intrathecal tumours cause increased pressure in spinal canal, which can cause posterior vertebral scalloping.
Common primary cord tumours include ependymoma (adults) and astrocytoma (kids). Intradural extramedullary tumours such as nerve sheath tumours, meningiomas and mets can also cause this.
Normal variant If mild, with no other skeletal abnormalities. Often followed up to exclude other causes.
Cystic presacral mass
Top 3 DDx:
- Sacrococcygeal teratoma (SCT)
- Rectal duplication cyst
- Anterior sacral meningocele
Other DDx:
- Lymphatic malformation
- Dermoid cyst
- Ovarian cyst
SCT Rare tumours, but most common caudal tumours in indants and can be extrapelvic, intrapelvic or mixed. Most presenting in first few months are benign, later presenting = more malignant risk. Cystic lesions and those in girls are more often benign.
60% calcify. Heterogenous and variably cystic, solid and fatty depending on composition. MRI demonstrates tumour extent and defines degree of spinal involvement. Rx involves resection of coccyx.
Rectal duplication cyst 5% of enteric duplication cysts. THin walled, spherical, uni or multilocular. May communicate with rectum.
Smooth muscle walls lined with rectal mucosa, causing hypo and hyperechoic US layers (gut signature).
Anterior sacral meningocele Rare herniations of CSF distended meninges through sacral foramen or deficit.
MRI defiens the lesion, CT demonstrates bony defect.
May be associated with GU or anorectal malformations, as well as NF-1. May be part of Currarino triad (Anorectal malformation, sacral osseous defect and presacral mass).
Lymphatic malformation Macrocystic lymphatic malformations are fluid filled lymphatic spaces, due to poorly connected lymphatic vessels.
Thin walled, uni or multilocular cysts with enhancing walls and septa.
Dermoid cyst Rare in presacral region. Cystic masses with dermal elements, fatty appearance on imaging. Associated with anorectal and osseous defects as part of currarino triad.
Ovarian cyst Common in neonatal girls, may be large. Due to maternal hormones.
US confirms ovarian origin. >5cm are increased risk of torsion.
Often midline, they’re prerectal rather than presacral.
Aggressive lesion in long bone
Top 3 DDx:
- Osteomyelitis
- Osteosarcoma
- Ewing sarcoma
Other DDx:
- LCH
- Mets
Osteomyelitis Wide spectrum of radiographic appearances. Clinical Hx of fever or recent infection is helpful.
Radiographic findings include lytic lesions with varying aggressive features (bone resorption, periostitis, sclerotic nidus, draining cloaca, subcutaneous gas).
Degree of sclerosis around and within the lesion varies. CT and MRI are useful if diagnosis in doubt or treatment not working.
Osteosarcoma Commonest primary childhood bone malignancy.
Aggressive lesion in metaphysis of long bone, with abnormal new bone formation. Aggressive lesions, may appear mainly lytic.
Telangiectatic osteosarcoma may have fluid-fluid levels, resembling aneurysmal bone cyst. MRI is useful to detect nearby skip lesions.
PET CT is useful to detect bone mets.
Ewing sarcoma Second commonest childhood bone malignancy. Lytic, medullary based metadiaphyseal lesion with aggressive periosteal reaction, but can be purely lytic or sclerotic.
Large soft tissue masses are common. Long bones more common in children, flat in adolescents and adults. Presents with pain, fever and elevated inflammatory markers.
MRI for local staging.
LCH May present as solitary or multifocal lytic lesion. Varied X-ray appearance, therefore a reasonable differentual in any aggressive or benign lesion under 30.
Metastases Secondary malignancies commonly affect bones. Leukaemia is commonest in long bones in children, other common neoplasms metastasizing to bone include neuroblastoma and lymphoma.
Metastatic foci often present as lytic foci with permeative or moth eaten appearance.
Multiple non-cystic renal masses in a child
Top 3 DDx:
- Multifocal pyelonephritis
- Lymphoma/leukaemia
- Tuberous sclerosis (TS)
Other DDx:
- Nephroblastomatosis
- Wilms
Multifocal pyelonephritis Usually from ascending infection. Lesions often ill defined, more common in upper and lower poles if a/w reflux.
US varies, often normal. CT and MRI show hypoenhancing masses or patchy striations extending peripherally.
Lymphoma/leukaemia Renal lymphoma often with multifocal NHL, esp Burkitt. Multiple parenchymal masses causing renal enlargement, but can cause renal diffuse infiltration or single mass.
Hypoechoic on US and little enhancement.
Leukaemia appears as homogenous renal enlargement.
TS Systemic AD disorder of multuple hamartomas and benign tumours of brain, skin, lungs, kidneys, heart.
AML is commonest renal lesion, often multiple. Renal cysts and rarely RCC also occur.
in TS, AMLs occur earlier, larger and more often multiple and bilateral, increasing in size at puberty. Prophylactic embolisation usually done >4cm.
Echogenic without shadowing on US. Fat density/signal on CT/MRI.
Nephroblastomatosis Multifocal or diffuse renal rests, can be single.
Strong association with Wilms. Annual surveillance to exclude malignant degeneration.
Also a/w Beckwith Wiedemann, Trisomy 18, Drash, aniridia, WAGR (Wilms, Aniridia, Genital abnormalities, Retardation).
Homogenous and non-enhancing on CT. Heterogenous on MRI with homogenous enhancement.
Wilms May present with multiple “synchronous” tumours rarely.
Erlenmeyer flask deformity
Top 3 DDx:
- Osteopetrosis
- Fibrous dysplasia
- Gaucher disease
Other DDx:
- Haemoglobinopathy
- Multiple hereditary exostoses
Osteopetrosis Inherited disorder of osteoclast dysfunction, causing accumulation of primary spongiosa in medullary spaces.
Causes erlenmeyer flask deformity, increased bone density, encroachment on medullary spacee, bone in bone appearance, alternating lucent and dense metaphyseal bands.
Complicated by fractures, anaemia and thrombocytopenia.
Fibrous dysplasia Mono or polyostotic. Expansile lesions from central bone, rarely involve epiphyses.
Density varies on amount of osseous or fibrous tissue, but classically ground glass matrix.
Complicated by pathological fracture.
Polyostotic is more aggressive, and affects one side of the body. A/W McCune albright (Precocious puberty, cafe-au-lait spots) and Mazabraud (soft tissue myxomas) syndromes
Gaucher disease Rare, inherited metabolic disorder of lysosomal enzyme deficiency.
Imaging shows osteopenia, medullary expansion and remodelling.
Complicated by bone infarcts, AVN and pathologic fractures.
MRI determines extent of marrow infiltration, of similar signal to haematopoietic marrow.
Haemoglobinopathy Bony changes are due to marrow hyperplasia and vascular occlusion. Marrow hyperplasia causes osteopenia, hair on end skull, remodelling.
Vascular occlusion causes AVN, bone infarcts and dactylitis. Physeal involvement may lead to growth disturbance.
Multiple hereditary exostoses Osteochondromatosis is AD. As with solitary lesions, cortex is continuous with underlying bone. Lesions causing Erlenmeyer flask deformity are sessile rather than pedunculated.
Complications include growth disturbance, pain (neurovascular bundle compression) and rarely malignant transformation.
Lytic skull lesion in a child
Top 3 DDx:
- Langerhans cell histiocytosis (LCH)
- Epidermoid cyst
- Neoplasm
Other DDx:
- Infection
- Leptomeningeal cyst
LCH Skull is commonest site of involvement, with well defined lytic lesion without sclerotic involvement, and bevelled edge from greater involvement of inner vs outer table.
Can also be round, lucent skull defect with central dense nidus (button sequestrum).
Clinically pain, palpable mass, systemic symptoms.
Epidermoid cyst Second commonest solitary skull lesions in kids. If involving diploic space, appearances can mimic LCH, with well defined expansile lytic lesions without central matrix.
Rim may be sclerotic. MRI shows increased DWI signal (characteristic).
Neoplasm Poorly defined lytic lesions in all bones, including skull, from leukaemia, Ewings and mets from neuroblastoma.
Localised bone destruction in leukaemia are surrounded by normal bone, likely mets. Tend to have aggressive appearance.
Infection Osteomyelitis ranges from normal to mimicking aggressive neoplasm.
Skull may show lytic lesions with poorly defined margins, may have overlying soft tissue oedema.
Subacute or chronic may be rounder, well defined lucency with central nidus or sequestrum.
Leptomeningeal cyst Well defined bone defect arising from traumatic laceration of dura, exposing bone to CSF pulsations which widen the frature line (growing fracture).
Uncommon complication of skull fractures, common in kids under 3.
AVN of femoral head
Top 3 DDx:
- Legg-Calve-Perthes disease (LCP)
- Traumatic injury
- Sickle cell disease
Other DDx:
- Corticosteroid use
- Gaucher disease
- Meyer dysplasia
LCP Common 5-8YO in boys, limp and decreased ROM with no trauma Hx.
Femoral head AVN from impaired blood supply across physis.
MRI shows linear low T1. X-rays may show effusion, thinning of chondral plate and lucent epiphysis, which then becomes denser and fragmented.
In reparative phase, normal bone replaces sclerotic, and femoral head becomes smoother.
Long term prognosis affected by femoral head contour and congruence between it and acetabulum.
Trauma Injury to fragile vessels may cause ischaemia and AVN, either trauma itself or relocation of dislocated hip. Risk proportional to degree of flexion and abduction.
Sickle cell Abnormal RBCs occlude vessels, and subsequent hypoxia exacerbates the problem. Femoral and humeral heads commonly involved, along with vertebral endplates and diametaphyses of long bones.
Corticosteroids Demineralisation and fat emboli are some mechanisms. High dose = more risk. More likely bilateral.
Gaucher Inability to clear glucosylceramide causes increased pressure, occluding intraosseous sinusoids and causing infection.
In addition to AVN, radiographs show osteopenia, medullary expansion and bony remodelling.
Meyer dysplasia Affects proximal femoral epiphyses, appearing irregular and small. 2-4 boys, painless, often bilateral. Radiographic appearance mimics AVN.
Vascular abnormality with oeseophageal and tracheal compression
Top 3 DDx:
- Aberrant right subclavian artery
- Double aortic arch
- Right arch with aberrant left subclavian
Other:
- Pulmonary sling
- Brachiocephalic artery compression syndrome
Aberrant right subclavian Common isolated arch anomaly, rarely symptomatic.
RCSA is last branch of a left sided arch. Courses behind oesophagus, posteriorly indenting the oesophagus. Not complete vascular ring.
Double aortic arch Commonest symptomatic arch anomaly. Right arch higher and larger in 75%.
2 arches join posteriorly to form descending aorta (left usually). Arches encircle oesophagus and trachea and may compress them.
Posterior, bilateral indentation of oesophagus and narrowing of trachea. Enhanced CT/MRI demonstrate it and effects on surrounding structures.
Right arch, aberrant left subclavian LCSA arises from diverticulum of Kommerell, passes posterior to oesophagus to left upper extremity.
Ductal ligament extends from LCSA to Left PA, completing vascular ring.
Pulmonary sling Left PA arises from right PA, passes between trachea and oesophagus to left lung. Anterior indent on oesophagus and posterior on trachea.
A/w complete tracheal rings, which may also contribute to respiratory symptoms.
Brachiocephalic artery compression syndrome Compression of trachea by brachiocephalic artery causes resp compromise in infants. Usually left aortic arch. Course of brachiocephailc artery may be abnormal.
Symptoms may result from underlying tracheal maldevelopment.
Surgical reimplantation or suspension may help resp symptoms.
