Eduovisual
Pediatrics (System-Integrated)
Cystic fibrosis: pediatric diagnosis and management
— Loss of CFTR function → thick, dehydrated secretions → obstruction of airways, pancreatic ducts, biliary tree, vas deferens, and intestinal lumen.
— F508del is the most common pathogenic variant in US/Northern European populations (~70% of alleles); >2,000 variants identified, ~400 disease-causing.
— ~1 in 3,500 live births in non-Hispanic White infants; lower incidence in Black (~1:15,000) and Asian populations.
— Median predicted survival now exceeds 50 years with modern CFTR modulators and multidisciplinary care.
— Positive newborn screen (elevated immunoreactive trypsinogen ± CFTR variant panel) — universal in all 50 states.
— Meconium ileus in a neonate — ~20% of CF infants present this way; nearly pathognomonic.
— Failure to thrive with steatorrhea, foul bulky stools, or fat-soluble vitamin deficiency (A, D, E, K).
— Recurrent sinopulmonary infections, especially with Pseudomonas aeruginosa, Staphylococcus aureus, or Burkholderia cepacia.
— Nasal polyps in a child (rare without CF or aspirin sensitivity).
— Rectal prolapse, distal intestinal obstruction syndrome, or pancreatitis in older children.
— Salty-tasting skin, hyponatremic hypochloremic metabolic alkalosis (pseudo-Bartter).
— Male infertility from congenital bilateral absence of the vas deferens (CBAVD).
Board pearl: A White infant with meconium ileus or a toddler with steatorrhea, recurrent pneumonia, and FTT is CF until proven otherwise—order a sweat chloride test even with a normal newborn screen, which can have false negatives.
— Meconium ileus: bilious vomiting, abdominal distension, failure to pass meconium in first 24–48h; abdominal x-ray shows dilated loops with "ground-glass" or "soap-bubble" appearance in RLQ; risk of volvulus/perforation.
— Prolonged neonatal jaundice (cholestatic) or vitamin K deficiency bleeding.
— Hyponatremic dehydration during hot weather (excess sweat Na/Cl loss).
— Positive newborn screen requiring confirmatory testing.
— Failure to thrive despite voracious appetite — the classic "hungry but skinny" child.
— Steatorrhea: greasy, foul, floating, bulky stools from pancreatic exocrine insufficiency (~85% of CF patients).
— Recurrent wheezing/cough misdiagnosed as asthma or "recurrent bronchiolitis."
— Rectal prolapse (consider CF in any child <5 with prolapse).
— Fat-soluble vitamin deficiency signs: night blindness (A), rickets (D), hemolysis/neuropathy (E), bleeding (K).
— Chronic productive cough, sputum cultures positive for S. aureus → later P. aeruginosa.
— Nasal polyps, chronic sinusitis.
— Digital clubbing, declining exercise tolerance.
— Pancreatitis (paradoxically in pancreatic-sufficient CF phenotypes).
— CF-related diabetes (CFRD) emerging in teens.
— Delayed puberty, low BMI.
— Family history of CF, infertility, recurrent pneumonia, or sibling deaths.
— Newborn screen results and any confirmatory sweat test.
— Stool pattern, growth trajectory (plot on CDC curves).
— Frequency of antibiotic courses, hospitalizations, sputum cultures.
— Pancreatic enzyme use, vitamin supplementation, modulator therapy adherence.
Step 3 management: When a primary care provider sees a child with >2 pneumonias/year + poor growth + bulky stools, the next best step is sweat chloride testing at an accredited CF center, not empiric antibiotics or asthma escalation. Refer concurrently to a CF Foundation–accredited care center.
— Plot weight, length/height, and BMI on standardized curves at every visit; BMI ≥50th percentile by age 2 correlates with better FEV₁ at age 6.
— Wasted appearance, decreased subcutaneous fat, temporal wasting.
— Digital clubbing (Schamroth sign loss) — develops with chronic hypoxemia/inflammation.
— Nasal polyps (pale, glistening masses) — present in 10–30% of CF children.
— Tender maxillary/frontal sinuses, mucopurulent rhinorrhea.
— Dental enamel hypoplasia from chronic illness/antibiotics.
— Tachypnea, increased AP diameter ("barrel chest") from air trapping.
— Coarse crackles, wheezes, prolonged expiratory phase.
— Hyperresonance to percussion; accessory muscle use during exacerbations.
— Pulse oximetry: baseline SpO₂ trending down over years; <90% suggests advanced disease.
— Late: loud P2, RV heave, JVD, hepatomegaly from cor pulmonale (pulmonary hypertension from chronic hypoxia).
— Resting tachycardia during exacerbations; orthostatic changes if salt-wasting.
— Distension, palpable stool in RLQ (DIOS), hepatomegaly (CF liver disease, ~5–10%).
— Splenomegaly if portal hypertension from biliary cirrhosis.
— Rectal prolapse on Valsalva exam in young children.
— Salty taste when kissing the child (classic parental report).
— Kyphosis from vertebral compression (low vitamin D, chronic steroids).
— Arthropathy (CF-related arthritis or hypertrophic osteoarthropathy).
— Tanner staging delay; in adolescent males, small/absent vas deferens on exam.
Key distinction: Digital clubbing in a child is never normal — CF, cyanotic congenital heart disease, bronchiectasis, and inflammatory bowel disease top the differential. In a child with clubbing + chronic cough + steatorrhea, CF is the answer until disproven by sweat chloride. Document baseline SpO₂, BMI percentile, and clubbing at every CF visit — these drive longitudinal management decisions.
— Step 1: Immunoreactive trypsinogen (IRT) on dried blood spot at 24–72h of life; elevated due to pancreatic duct obstruction.
— Step 2 (varies by state): repeat IRT, or CFTR variant panel (IRT/DNA algorithm).
— Positive NBS → refer to accredited CF center for sweat chloride test by 4 weeks of age (ideally by 2 months).
— False negatives occur (~2%); a normal NBS does NOT rule out CF if clinical suspicion is high.
— Performed at CF Foundation–accredited lab; minimum 75 mg sweat.
— ≥60 mmol/L = diagnostic of CF.
— 30–59 mmol/L (infants <6 months: 30–59) = intermediate → genetic testing.
— <30 mmol/L = CF unlikely (but does not exclude CFTR-related disorders).
— Two positive sweat tests on separate days confirm diagnosis.
— Fecal elastase-1 <100 µg/g confirms pancreatic exocrine insufficiency.
— 72-hour fecal fat (rarely used now) for steatorrhea quantification.
— Fat-soluble vitamin levels (A, D, E, INR for K).
— CBC (anemia of chronic disease), CMP, GGT, fasting glucose, HbA1c.
— Hyponatremic hypochloremic metabolic alkalosis (pseudo-Bartter syndrome) in infants.
— Chest x-ray: hyperinflation, peribronchial cuffing, "tram tracks," upper lobe predominant bronchiectasis later.
— High-resolution CT chest: bronchiectasis, mucus plugging, tree-in-bud — more sensitive than CXR.
— Abdominal x-ray for meconium ileus or DIOS: dilated loops, soap-bubble pattern.
— Abdominal US for biliary disease, hepatic steatosis, portal hypertension.
— Oropharyngeal swab or sputum culture at every visit; surveillance for S. aureus, P. aeruginosa, H. influenzae, Burkholderia.
Board pearl: Diagnosis requires (1) clinical features OR positive NBS OR sibling with CF PLUS (2) sweat Cl⁻ ≥60 mmol/L on two occasions OR two CF-causing CFTR mutations OR abnormal nasal potential difference. Memorize this triad — Step 3 loves the diagnostic algorithm.
— Indicated for: intermediate sweat test, atypical presentations, family planning, modulator therapy eligibility.
— Initial panel screens for ~23 common variants (ACMG-recommended); expanded sequencing if negative but suspicion persists.
— Two CF-causing variants in trans (one from each parent) confirms diagnosis.
— Class I–III mutations (e.g., F508del, G551D) → severe phenotype, pancreatic insufficiency.
— Class IV–V mutations → residual CFTR function, often pancreatic sufficient, milder disease.
— Reserved for diagnostically ambiguous cases at specialized centers.
— Measures CFTR-mediated ion transport directly; abnormal in CF.
— Begin at age 5–6 when child can cooperate; FEV₁ is the key longitudinal marker.
— Obstructive pattern: ↓FEV₁/FVC, ↓FEV₁, ↑RV/TLC (air trapping).
— Infant PFTs (raised volume rapid thoracoabdominal compression) at specialized centers.
— Lung clearance index (LCI) via multiple breath washout — more sensitive than FEV₁ in early disease.
— Quarterly respiratory cultures including fungi and nontuberculous mycobacteria (NTM) annually.
— Identification of Burkholderia cepacia complex has prognostic and infection-control implications.
— Annual 2-hour OGTT starting at age 10; HbA1c is insensitive for CFRD.
— Diagnose CFRD if fasting glucose ≥126 or 2-hr ≥200.
— DXA scan starting at age 8–10 if risk factors; vitamin D level annually.
— Annual LFTs, GGT; ultrasound if abnormal or hepatomegaly.
Step 3 management: For a child with a borderline sweat chloride (30–59 mmol/L) and equivocal symptoms, the next best step is CFTR gene sequencing, not repeat sweat testing alone. If sequencing is also non-diagnostic but suspicion remains, refer to a CF center for nasal potential difference measurement. Document the diagnostic certainty — this drives modulator eligibility and insurance authorization.
— Quarterly visits with pulmonologist, dietitian, respiratory therapist, social worker, CF nurse coordinator.
— Annual labs, imaging, OGTT, microbiology surveillance, mental health screening.
— Care at an accredited CF Foundation center improves survival — refer early.
— Genotype (Class I–III = severe; IV–V = milder, residual function).
— Pancreatic status (insufficient vs sufficient by fecal elastase).
— FEV₁ % predicted — best single predictor of mortality.
— BMI percentile — nutritional status drives lung outcomes.
— Chronic Pseudomonas infection — accelerates decline.
— CFRD presence — doubles mortality risk.
— NTM, Burkholderia cepacia — worse prognosis.
— Airway clearance: chest physiotherapy, high-frequency chest wall oscillation vest, autogenic drainage, PEP devices — daily, twice daily minimum.
— Antibiotics: chronic suppressive (inhaled tobramycin, aztreonam), exacerbation treatment, eradication of new Pseudomonas.
— Anti-inflammatories: azithromycin (immunomodulatory), high-dose ibuprofen (selected patients).
— CFTR modulators: genotype-directed — transformative.
— Adequate nutrition: high-calorie, high-fat diet (110–200% of RDA), enzyme replacement, vitamins.
— Dornase alfa (rhDNase) nebulized daily — cleaves extracellular DNA in purulent sputum; improves FEV₁ and reduces exacerbations.
— Hypertonic saline 7% nebulized BID — rehydrates airway surface liquid.
— All routine pediatric vaccines on schedule, annual influenza, RSV prophylaxis if eligible, COVID-19, pneumococcal (PCV20 then PPSV23).
CCS pearl: On a CCS case, after confirming CF diagnosis, order in this sequence: refer to CF center → start pancreatic enzymes with meals → fat-soluble vitamins (ADEKs) → airway clearance education → dornase alfa + hypertonic saline → respiratory cultures → CFTR genotype for modulator eligibility → schedule quarterly follow-up. Advance the clock 3 months to reassess weight gain and PFTs.
— Elexacaftor/tezacaftor/ivacaftor (ETI, Trikafta): approved for patients ≥2 years with at least one F508del allele (covers ~90% of US CF patients). Improves FEV₁ ~10–14%, reduces exacerbations 60%, weight gain, sweat Cl⁻ reduction.
— Ivacaftor (Kalydeco): gating mutations (e.g., G551D), age ≥1 month.
— Tezacaftor/ivacaftor, lumacaftor/ivacaftor: older combinations, largely supplanted by ETI.
— Monitor LFTs at baseline, 3 months, 6 months, then annually; eye exam for cataracts in children.
— Lipase-based enteric-coated capsules with every meal and snack containing fat.
— Dose: 500–2,500 lipase units/kg/meal; max 10,000 units/kg/day to avoid fibrosing colonopathy.
— Adjust based on stool consistency, weight gain, steatorrhea symptoms.
— Dornase alfa 2.5 mg nebulized once daily.
— Hypertonic saline 7% nebulized BID (pretreat with bronchodilator if reactive airways).
— Inhaled tobramycin (300 mg BID) or aztreonam (75 mg TID) in 28-day on/off cycles for chronic Pseudomonas.
— 250–500 mg three times weekly for patients ≥6 with chronic Pseudomonas; rule out NTM first (azithromycin monotherapy promotes macrolide resistance in Mycobacterium avium).
Board pearl: Before starting chronic azithromycin, always screen for nontuberculous mycobacteria with sputum AFB cultures. Macrolide monotherapy in unrecognized NTM infection breeds resistant M. abscessus or M. avium complex — a disaster for future treatment. This is a favorite Step 3 patient safety question.
— Definition: increased cough/sputum, ↓FEV₁ ≥10% from baseline, weight loss, new infiltrate, fever.
— CCS approach: admit if moderate/severe → obtain sputum culture → start two IV antipseudomonal agents from different classes (e.g., piperacillin-tazobactam or cefepime + tobramycin; add vancomycin if MRSA history).
— Duration: typically 14 days; monitor tobramycin levels (peak 8–12, trough <1), renal function, hearing.
— Intensified airway clearance 3–4×/day, nutrition optimization, IV correction of electrolytes.
— Inhaled tobramycin 300 mg BID × 28 days ± oral ciprofloxacin; aim to prevent chronic colonization.
— Uncomplicated: gastrografin (water-soluble contrast) enema under fluoroscopy — both diagnostic and therapeutic.
— Complicated (perforation, volvulus, atresia): surgical resection ± temporary ostomy.
— Oral/NG polyethylene glycol or gastrografin; surgery only if obstruction fails medical management.
— Refer when FEV₁ <30% predicted, rapid decline, hypercapnia, pulmonary hypertension, or recurrent massive hemoptysis.
— Bilateral lung transplant; 5-year survival ~60%.
— Burkholderia cenocepacia is a relative/absolute contraindication at many centers.
— For decompensated cirrhosis with portal hypertension; often combined with lung transplant.
CCS pearl: For a CF patient admitted with exacerbation, the bundled order set is: sputum Cx → IV dual antipseudomonals → aggressive airway clearance Q6h → continue home modulators/enzymes/vitamins → nutrition consult → daily weights → PFTs at discharge. Don't forget VTE prophylaxis if adolescent.
— Repeated aminoglycoside courses (IV tobramycin, amikacin) cause cumulative nephrotoxicity and ototoxicity.
— Use once-daily extended-interval dosing (10 mg/kg IV q24h) to minimize nephrotoxicity vs traditional q8h; equally efficacious.
— Monitor trough levels (<1 mg/L) before next dose; baseline and weekly SCr.
— Avoid concomitant NSAIDs, IV contrast, vancomycin if possible during aminoglycoside courses.
— Audiology baseline and annual screening; high-frequency hearing loss is often subclinical but progressive.
— CF-related nephrolithiasis (hyperoxaluria, low citrate): hydration, dietary counseling.
— CF liver disease (CFLD) affects 5–10%; ranges from elevated LFTs/steatosis to focal biliary cirrhosis, multilobular cirrhosis, portal hypertension.
— Annual LFTs, GGT, platelets; ultrasound if abnormal or hepatomegaly.
— Ursodeoxycholic acid (UDCA) historically used though evidence for disease modification is weak; still common practice.
— Avoid hepatotoxic drugs when possible.
— CFTR modulators can cause transaminitis — check LFTs at baseline, 3 mo, 6 mo, then annually; hold if ALT/AST >5× ULN or >3× ULN with bilirubin elevation.
— Modulators in moderate-severe hepatic impairment: dose reduction (e.g., ETI: every other day in Child-Pugh B; not recommended in C).
— Renal impairment: minimal modulator adjustment; aminoglycosides require careful dosing.
— Hepatitis A and B vaccination strongly recommended; CFLD patients especially vulnerable.
— CFRD with renal involvement: avoid metformin if GFR <30; insulin is preferred (and is first-line in CFRD anyway).
Step 3 management: Before each IV aminoglycoside course, document baseline audiogram, SCr, and weight for once-daily dosing. After 2 weeks, recheck SCr and trough. If SCr rises ≥0.3 mg/dL or 50% from baseline → hold and switch class. This is a recurring Step 3 patient safety theme.
— Begin transition planning at age 12–14; transfer to adult CF program typically by 18–21 years.
— Address adherence (modulators, airway clearance), mental health, substance use, sexual health.
— Annual depression and anxiety screening (PHQ-9, GAD-7) starting age 12 — CF Foundation/ECFS guideline; rates 2–3× general population.
— Males: ~98% infertile due to congenital bilateral absence of the vas deferens (CBAVD) — spermatogenesis normal; fatherhood possible via TESE + IVF/ICSI.
— Females: fertility reduced (thick cervical mucus, anovulation if undernourished) but pregnancies common, especially on modulators (post-Trikafta "baby boom").
— Contraception counseling: most methods safe; CFRD does not preclude OCPs but consider thrombosis risk if severe disease/inactivity.
— Pre-conception: optimize BMI ≥22, FEV₁ ideally >50% predicted, control CFRD, screen for B. cepacia.
— Modulators in pregnancy: ETI is continued in most cases — risk of clinical deterioration on discontinuation outweighs uncertain fetal risk; shared decision-making.
— Monitor: monthly OB + CF visits, growth scans, OGTT at 24–28 weeks (CFRD often emerges).
— Increased caloric needs; PERT dose adjustment.
— Breastfeeding: encouraged; ETI passes into breast milk in small amounts — current guidance supports continuation.
— Infants <2 years: focus on nutrition, vitamin D, salt supplementation, early modulator initiation (ETI ≥2y; ivacaftor ≥1 month for eligible genotypes).
— School-age: school accommodations (504 plan), enzyme administration plan, infection-control distancing from other CF patients.
Board pearl: Two CF patients should never be in the same room or clinic waiting area — cross-infection with Pseudomonas, Burkholderia, MRSA, and NTM dramatically worsens outcomes. Mandatory 6-foot distancing and masking is standard CF Foundation infection-control policy and a high-yield patient safety pearl.
— Acute pulmonary exacerbations — leading cause of morbidity and hospitalization.
— Bronchiectasis — irreversible, upper-lobe predominant.
— Chronic Pseudomonas aeruginosa colonization with mucoid biofilm — virtually impossible to eradicate.
— Allergic bronchopulmonary aspergillosis (ABPA) — 5–15% of CF; suspect with ↓FEV₁, IgE >500, positive Aspergillus serology, eosinophilia, central bronchiectasis → treat with oral steroids ± itraconazole.
— Massive hemoptysis (>240 mL/24h) — hold NSAIDs, azithromycin; bronchial artery embolization.
— Pneumothorax — risk increases with disease severity.
— Respiratory failure and cor pulmonale — late-stage.
— NTM disease (M. abscessus, M. avium complex) — challenging treatment; transplant contraindication for some.
— Pancreatic insufficiency (~85%), pancreatitis (in pancreatic-sufficient patients).
— Distal intestinal obstruction syndrome (DIOS) — RLQ pain, palpable fecal mass.
— Meconium ileus equivalent, intussusception, rectal prolapse.
— Fibrosing colonopathy from excessive PERT dosing (>10,000 units lipase/kg/day).
— GERD common; consider PPI.
— Focal biliary cirrhosis, multilobular cirrhosis, portal hypertension, gallstones.
— CF-related diabetes (CFRD) — affects 20% adolescents, 50% adults; insulin is treatment of choice.
— Osteopenia/osteoporosis — DXA screening; vitamin D, calcium, weight-bearing exercise.
— Delayed puberty, hypogonadism.
— Nephrolithiasis, aminoglycoside-induced AKI.
— Depression, anxiety — screen annually from age 12.
Key distinction: Differentiate a pulmonary exacerbation (treat with antibiotics) from ABPA (treat with steroids ± antifungals). Both present with declining FEV₁ and worsening cough — but ABPA shows eosinophilia, IgE >500–1000, positive Aspergillus IgE/IgG, and central bronchiectasis. Missing ABPA leads to progressive lung damage despite "appropriate" antibiotic courses.
— Acute exacerbation with FEV₁ drop >10% not responding to outpatient oral antibiotics.
— Hypoxemia (SpO₂ <92% on room air, or drop from baseline).
— Inability to maintain hydration/nutrition; significant weight loss.
— Hemoptysis >5 mL or new pneumothorax.
— Suspected DIOS failing oral therapy.
— IV antibiotics needed (resistant organism, prior failure).
— Concerns about home support, adherence, or social factors.
— Respiratory failure: rising PaCO₂, mental status changes, severe accessory muscle use.
— Massive hemoptysis requiring embolization or airway protection.
— Hemodynamic instability (sepsis, tension pneumothorax).
— Noninvasive ventilation (BiPAP) often first-line; intubation associated with poor outcomes — avoid if possible, but do not delay if needed.
— CF center pulmonologist — every newly diagnosed patient.
— GI/hepatology for CFLD, pancreatitis, DIOS.
— Endocrinology for CFRD diagnosis and management.
— ENT for chronic sinusitis, polyps.
— Genetics counseling for family planning, sibling testing.
— Reproductive endocrinology for fertility.
— Lung transplant evaluation when FEV₁ <30%, rapid decline, or recurrent severe exacerbations.
— Palliative care — early integration improves quality of life; not just end-of-life.
— Single-patient rooms with contact + droplet precautions.
— Dedicated equipment; no shared therapy areas with other CF patients.
— Screen roommates' microbiology.
— Day 1: cultures, IV access, dual antipseudomonals, airway clearance Q6h, nutrition, modulator continuation.
— Day 3–5: reassess clinical response, narrow antibiotics based on sensitivities.
— Day 14: PFTs, discharge planning, follow-up in 1–2 weeks.
CCS pearl: Before discharge, always confirm: PFTs back to baseline (or new baseline documented), home IV plan if completing course outpatient, follow-up in CF clinic within 1–2 weeks, prescriptions refilled, education reviewed. Missing the post-discharge visit is the #1 readmission driver.
— Autosomal recessive ciliary dysfunction.
— Triad: chronic sinusitis, bronchiectasis, situs inversus (Kartagener syndrome in ~50%).
— Neonatal respiratory distress in term infants is a clue.
— Sweat chloride normal; diagnose via nasal nitric oxide (low), ciliary biopsy with electron microscopy, genetic testing.
— Male infertility (immotile sperm) but normal vas deferens.
— Common variable immunodeficiency (CVID): low IgG/IgA/IgM, poor vaccine response.
— X-linked agammaglobulinemia (Bruton): boys, absent B cells, no tonsils, sinopulmonary infections after 6 months.
— Hyper-IgE (Job) syndrome: eczema, cold abscesses, retained primary teeth, eosinophilia.
— Check quantitative immunoglobulins, vaccine titers, lymphocyte subsets.
— Lower-lobe emphysema (less common in pediatrics), neonatal hepatitis.
— Serum A1AT level + phenotyping (PiZZ).
— Severe persistent asthma can cause bronchiectasis but typically lacks pancreatic/GI features.
— Post-pertussis, post-measles, post-adenovirus, post-TB — focal bronchiectasis on CT.
— Recurrent aspiration (neuromuscular disease, severe GERD, TE fistula): right lower lobe predominant.
— Rare: yellow nails, lymphedema, bronchiectasis/pleural effusions.
Key distinction: CF vs PCD — both cause chronic sinopulmonary disease and bronchiectasis, but CF has pancreatic insufficiency, elevated sweat chloride, CBAVD, and upper-lobe predominant disease, while PCD has situs inversus in ~50%, normal sweat chloride, low nasal nitric oxide, and normal pancreatic function. Order sweat chloride first in any child with bronchiectasis + chronic sinusitis. If normal and suspicion remains, pursue nasal NO and ciliary studies.
— Shwachman-Diamond syndrome: pancreatic insufficiency + bone marrow failure (neutropenia) + metaphyseal dysplasia + normal sweat chloride. SBDS gene mutations.
— Pearson syndrome: mitochondrial DNA deletion, pancreatic insufficiency, sideroblastic anemia.
— Johanson-Blizzard syndrome: pancreatic insufficiency, nasal alar hypoplasia, deafness.
— Celiac disease: villous atrophy → malabsorption, anti-TTG IgA positive, biopsy diagnostic; no pulmonary disease.
— Chronic giardiasis: stool antigen positive.
— Cow's milk protein allergy in infants.
— Inflammatory bowel disease (especially Crohn's) in older children.
— Lactose intolerance, fructose malabsorption, short bowel syndrome, autoimmune enteropathy.
— Hirschsprung disease: distal aganglionosis, rectal exam → explosive stool; biopsy confirms. Can coexist with CF.
— Meconium plug syndrome: associated with prematurity, maternal diabetes; transient.
— Ileal atresia: structural; surgical.
— Small left colon syndrome.
— Tracheoesophageal fistula (H-type): recurrent right upper lobe pneumonia, choking with feeds.
— Vascular ring: stridor, dysphagia, recurrent infection in same lobe.
— Pulmonary sequestration: recurrent infection in same segment.
— Foreign body aspiration: sudden onset, focal findings.
— CF (pseudo-Bartter) vs Bartter syndrome (true tubular defect, polyuria, normal sweat Cl⁻) vs pyloric stenosis (projectile vomiting, palpable olive).
Board pearl: A child with pancreatic insufficiency + neutropenia + skeletal dysplasia is Shwachman-Diamond, not CF — sweat chloride normal. A child with failure to thrive + diarrhea + dermatitis herpetiformis or iron-deficiency anemia is celiac disease. Always anchor on the complete phenotype, not isolated features, when sorting Step 3 differentials.
— CFTR modulator (ETI if F508del-eligible) — lifelong.
— Pancreatic enzymes with every meal and fat-containing snack.
— Fat-soluble vitamins (ADEK preparation) daily.
— Dornase alfa nebulized daily.
— Hypertonic saline 7% nebulized BID.
— Inhaled tobramycin/aztreonam 28-day on/off cycles if chronic Pseudomonas.
— Azithromycin 3×/week if chronic Pseudomonas (NTM-negative).
— PPI if GERD or to enhance enzyme efficacy.
— Salt supplementation as needed.
— Routine pediatric schedule, annual influenza ≥6 months, COVID-19, pneumococcal (PCV20 → PPSV23), hepatitis A/B, RSV (palivizumab/nirsevimab in eligible infants), HPV at 9–11 years.
— Hand hygiene; mask in healthcare settings; no contact with other CF patients.
— Avoid hot tubs, stagnant water (Pseudomonas reservoirs).
— Avoid construction sites and compost (Aspergillus).
— Pet hygiene; no reptiles (Salmonella).
— Goal BMI ≥50th percentile for children; >22 kg/m² for adolescent females, >23 for males.
— High-calorie (110–200% RDA), high-fat (35–40% calories) diet.
— Oral supplements, enteral feeds via G-tube if BMI cannot be achieved.
— Regular aerobic + resistance exercise (improves mucus clearance, bone density, mood).
— No smoking, no vaping; avoid secondhand smoke.
— Sun protection (some modulators photosensitize).
— Genetic counseling for parents (1/4 recurrence risk), siblings, future pregnancies.
— Carrier screening for partners of CF patients planning children.
Step 3 management: At every well visit, reconcile the medication list, verify modulator adherence (ask about pill counts/refills), confirm enzyme dosing matches current weight, and review annual surveillance schedule: OGTT (≥10y), DXA (≥8y if risk factors), NTM culture, eye exam (on ivacaftor), audiogram if aminoglycoside courses. Adherence drops sharply in adolescence — address proactively.
— Every 3 months at accredited CF center; more often if unstable.
— Each visit: weight/height/BMI, vitals, SpO₂, PFTs (age ≥6), respiratory culture, medication reconciliation, adherence review, psychosocial screen.
— CBC, CMP, GGT, lipids, vitamin A/D/E, INR (vit K function).
— OGTT starting age 10 (CFRD screen).
— Sputum/oropharyngeal AFB culture (NTM).
— Chest imaging (CXR annually; CT every 2–4 years or as indicated).
— DXA (age 8–10 if risk factors; routinely by 18).
— Depression/anxiety screening age ≥12 (PHQ-9, GAD-7).
— Audiology if aminoglycoside-exposed.
— Ophthalmology if on ivacaftor (cataract risk in children).
— LFTs: baseline, 3 months, 6 months, then annually (more often if abnormal).
— Hold modulator if ALT/AST >5× ULN or >3× with bilirubin >2× ULN.
— Daily airway clearance: HFCWO vest, PEP, autogenic drainage — 2–4×/day during exacerbations.
— Exercise prescription: 60 min moderate activity/day; structured program for advanced disease.
— Quarterly dietitian visit; calorie counts, enzyme dose review, supplement adjustments.
— Consider G-tube if BMI fails to reach 50th percentile despite optimization.
— Family taught airway clearance, enzyme dosing, infection control, when to call CF center.
— Adolescent self-management transition program.
— School 504 plan; emergency action plan.
— Refer to behavioral health if PHQ-9 ≥10 or GAD-7 ≥10; CBT and SSRIs as needed.
CCS pearl: After hospital discharge for an exacerbation, schedule CF clinic follow-up within 1–2 weeks to reassess PFTs, weight, adherence, and adjust regimen. Missing this visit predicts readmission. On a CCS case, the correct order is "Schedule follow-up appointment" — usually a free-text or menu action — before ending the case.
— NBS is mandated in all 50 states, but parents can opt out for religious reasons in most states.
— Disclosure of carrier status (one CFTR variant) from NBS is ethically complex — may reveal non-paternity or trigger family genetic testing; pre-test counseling is the standard.
— A positive NBS is not a diagnosis — communicate uncertainty carefully to avoid premature labeling.
— Sibling testing should be offered after parental counseling.
— Reproductive partner CFTR screening before conception in CF families.
— Carrier identification can affect insurance/employment in some contexts; GINA protects against most US health insurance and employment discrimination but not life/disability/long-term care insurance.
— As patients transition, increasing decision-making authority; confidentiality around mental health, sexuality, substance use is essential.
— Reproductive counseling: discuss fertility, contraception, modulator-related fertility recovery in females.
— Cross-infection between CF patients is a major patient safety issue — single rooms, masks, no shared waiting areas, no overlapping clinic appointments, dedicated equipment. Violations have led to outbreaks.
— Pediatric-to-adult CF center transfer is a high-risk handoff; structured transition program with shared records, warm handoff, and overlap visits reduces lost-to-follow-up.
— Discuss goals of care, transplant candidacy, code status proactively — not in crisis.
— Pediatric palliative care integration early improves outcomes and quality of life.
— Severe nonadherence threatening a child's life (e.g., refusing enzymes leading to malnutrition) may rise to medical neglect — consult social work and report per state law if persistent.
— CFTR modulators cost ~$300,000/year; ensure prior authorization, financial assistance, and equitable access.
— Modulator inequities by race/ethnicity exist (some variants in non-White populations not covered) — advocate for expanded testing/access.
Board pearl: A family refusing pancreatic enzymes citing "natural medicine," with a child showing severe failure to thrive, is a Step 3 setup for medical neglect reporting. First step: non-judgmental family meeting + social work; if persistent and child is at risk, report to Child Protective Services.
— CFTR on chromosome 7q31.2; autosomal recessive.
— F508del = phenylalanine deletion at position 508 = Class II processing defect = most common variant.
— Carrier frequency: ~1/25 White Americans.
— Class I (no protein) → Class V (reduced quantity); Class IV–V = milder.
— ≥60 mmol/L = diagnostic.
— 30–59 mmol/L = intermediate (any age now per 2017 consensus).
— <30 mmol/L = unlikely.
— Infant/young: S. aureus (including MRSA), H. influenzae.
— School-age/adult: P. aeruginosa (mucoid form), Burkholderia cepacia complex, Stenotrophomonas, Achromobacter, NTM.
— Meconium ileus → CF in 90%.
— Rectal prolapse in child → check sweat chloride.
— DIOS = adult equivalent of meconium ileus.
— Pancreatitis paradoxically occurs in pancreatic-sufficient CF.
— Pseudo-Bartter syndrome in infants (hypoNa hypoCl alkalosis).
— CFRD: insulin deficiency >> resistance; insulin is treatment.
— Osteoporosis common; vitamin D deficiency universal without supplementation.
— ETI (Trikafta): ≥2 years with ≥1 F508del.
— Check LFTs and eye exam (ivacaftor → cataracts in kids).
— Sweat chloride decreases on modulators (biomarker of response).
— Pulmonary disease >90% of mortality.
— Burkholderia cenocepacia infection — feared organism.
— CFRD doubles mortality.
— CBAVD in adult male with infertility → check CFTR (may be only manifestation).
— ABPA: IgE >500 + central bronchiectasis + eosinophilia.
— Nasal polyps in child = CF until proven otherwise.
Key distinction: Pancreatic sufficient CF (~15%, Class IV–V mutations) presents later, often with recurrent pancreatitis, milder pulmonary disease, normal growth — easy to miss. Always check fecal elastase to classify exocrine status, and don't exclude CF just because growth is normal.
— "A 1-day-old term infant has bilious vomiting and abdominal distension. Abdominal X-ray shows dilated bowel loops with a soap-bubble appearance in the RLQ. Next best step?"
— Answer: Gastrografin enema (diagnostic + therapeutic for meconium ileus) and sweat chloride testing at 2–4 weeks.
— "A 2-year-old has poor weight gain despite a good appetite, bulky greasy stools, and two episodes of pneumonia. Newborn screen was normal. Most appropriate next step?"
— Answer: Sweat chloride test (NBS can miss CF; clinical suspicion always trumps).
— "A child has sweat chloride of 45 mmol/L on two occasions. Best next step?"
— Answer: CFTR gene sequencing.
— "A 10-year-old with known CF has 2 weeks of increased cough, 5% weight loss, FEV₁ drop from 80% to 65%. Sputum grows mucoid Pseudomonas. Best management?"
— Answer: Admit for IV piperacillin-tazobactam + tobramycin × 14 days, intensified airway clearance.
— "Before starting chronic azithromycin for Pseudomonas suppression, what test must be done?"
— Answer: Sputum AFB cultures to rule out NTM.
— "Patient on elexacaftor/tezacaftor/ivacaftor presents with elevated ALT 4× ULN, bilirubin normal. Next step?"
— Answer: Hold modulator, recheck LFTs in 1–2 weeks; resume when normalized.
— "16-year-old male with CF asks about fatherhood. What do you tell him?"
— Answer: CBAVD causes obstructive azoospermia; spermatogenesis intact; fatherhood possible with TESE + ICSI.
— "Parents refuse enzymes citing alternative medicine; child is in 3rd percentile with severe FTT. What do you do?"
— Answer: Multidisciplinary meeting → social work → report medical neglect if persistent.
— "Child with pancreatic insufficiency and neutropenia, normal sweat chloride."
— Answer: Shwachman-Diamond syndrome.
Step 3 management: Step 3 stems emphasize next best management step, monitoring intervals, outpatient follow-up timing, and patient safety pitfalls (cross-infection, aminoglycoside ototoxicity, NTM before macrolides, fibrosing colonopathy from PERT overdose). Anchor every CF answer in the multidisciplinary, longitudinal management framework.
Cystic fibrosis is an autosomal recessive CFTR channelopathy that demands lifelong, multidisciplinary, genotype-directed care — anchored by sweat chloride diagnosis, CFTR modulator therapy, daily airway clearance, pancreatic enzymes plus fat-soluble vitamins, aggressive nutrition, vigilant surveillance for Pseudomonas/NTM/CFRD/CFLD, and proactive transition planning through adolescence into adult care.
Board pearl: When in doubt on a Step 3 CF stem, the answer is almost always "refer to/coordinate with the accredited CF center" plus the next genotype- or guideline-directed step.