Master Aarav, a 6-month-old male infant, 1st order child of non-consanguineous marriage from Patna, Bihar presented with complaints of progressive enlargement of head size since 2 months of age, inability to hold his neck, and downward rolling of the eyes noticed over the past 2 months.

HOPI

• Progressive Head Enlargement:
  • The infant was born with a head circumference of 35 cm (50th percentile) and had an uneventful early neonatal course after undergoing surgical repair of a lumbosacral spinal defect on Day 3 of life.
  • Around 2 months of age, the mother noticed that the infant's head began growing unusually fast; caps and bonnets became tight within days.
  • The calvarium became globular and disproportionately large compared to his small facial features (craniofacial disproportion).
• Fontanelle & Scalp Changes:
  • The mother observed that the soft spot on top of the head (anterior fontanelle) was constantly swollen, tense, and bulging, even when the baby was calm, asleep, or held upright.
  • Prominent, bluish, engorged blood vessels appeared over his forehead and scalp, becoming particularly visible when the infant cried.
  • The infant exhibited frequent bouts of high-pitched irritable crying, poor feeding, and occasional effortless vomiting.
• Eye Signs (Setting Sun Phenomenon):
  • Over the past 6 weeks, parents noticed that both eyes tended to deviate downwards, such that a wide white rim of sclera was constantly visible between the upper eyelid and the colored iris ("like a setting sun").
• Motor Development & Spine:
  • At 6 months of age, the infant is unable to support or balance his head when pulled into a sitting position (complete head lag due to mechanical head heaviness).
  • Social smile and cooing are present; he fixates on the mother's face.
  • The infant has decreased spontaneous movement of both lower limbs with inward turning of both feet (bilateral clubfoot / talipes equinovarus) noticed since birth.
  • Urine dribbles continuously in small drops throughout the day without a forceful continuous stream.

Pertinent Negatives in HOPI:

• No history of fever, neck stiffness, altered sensorium, or purulent ear discharge (rules out acute post-meningitic ventriculitis).
• No history of stridor, hoarse cry, choking during feeding, or apnoeic spells (rules out acute symptomatic brainstem compression from Arnold-Chiari Type II malformation).
• No history of loss of previously acquired milestones (rules out neurodegenerative megalencephalies like Alexander or Canavan disease).
• No history of infantile spasms or hypopigmented skin patches (rules out Tuberous Sclerosis with subependymal giant cell astrocytoma).
• No history of family members with large heads or adducted thumbs (rules out X-linked aqueductal stenosis / Bickers-Adams syndrome).

Past History

• Born with a ruptured lumbosacral cystic swelling (Meningomyelocele, $4\times 4\text{ cm}$), which underwent primary surgical excision and neural placode closure on Day 3 of life at a tertiary centre. Post-operative recovery was uneventful.
• No history of neonatal sepsis, meningitis, or intracranial hemorrhage.

Family history

• 1st-order child born to non-consanguineously married parents.
• Mother did not receive periconceptional folic acid supplementation during the first trimester.
• No family history of neural tube defects, hydrocephalus, or unexplained infant deaths.

Immunization history

• Immunized up to age with BCG, OPV 0-3, Pentavalent 1-3, Rota 1-3, and fIPV 1-2 as per the National Immunization Schedule.
• BCG scar is present on the left deltoid.

Dietary history

• Exclusively breastfed on demand (8–10 times per day); latches well; complementary feeding not yet initiated.

The expected calories and proteins should be calculated from the ideal body weight, not from current weight.

Socioeconomic and KAP

• Family resides in a semi-pucca house in suburban Patna.
• Father is a daily-wage technician; Mother is a homemaker.
• Socioeconomic Status: Lower-middle class (Modified Kuppuswamy Score: 10).
• Parents understand the need for surgical cerebrospinal fluid diversion (VP shunt) and long-term bladder management.

Summary of History

General head to toe examination

Pre-Examination Child Behavioral State

• Child State: Infant is calm, lying supine in quiet wakefulness, non-crying (Prechtl State 3).

Vitals

• Pulse Rate: 118 bpm, regular, normal volume.
• Respiratory Rate: 28/min, regular, no stridor or chest indrawing.
• Blood Pressure: 86/54 mmHg (normal for age).
• Temperature: 37.0°C (98.6°F), afebrile.

Cranial & Skull Examination (Detailed Semiology)

• Cranial Inspection:
  • Craniofacial Disproportion: Massive, globular, rounded calvarium towering over a small, triangular facies.
  • Frontal Bossing: Prominent overhanging forehead with depressed nasal root.
  • Dilated Scalp Veins: Prominent, engorged collateral scalp veins radiating over the frontal and temporal scalp.
  • Scalp skin is thin, stretched, translucent, and shiny.
• Fontanelles & Sutures:
  • Anterior Fontanelle: $5.0 \times 5.0\text{ cm}$, markedly tense, bulging above the bone margins, non-pulsatile in the upright sitting position.
  • Sutures: Coronal, sagittal, and lambdoid sutures are widely separated ($>1.0\text{ cm}$ diastasis on palpation).
• Percussion & Special Tests:
  • Macewen's Sign ("Cracked Pot Sound"): Percussion over the frontoparietal suture line elicits a resonant, high-pitched cracked pot sound.
  • Transillumination Test: Symmetrical light glow $<2.0\text{ cm}$ (indicates presence of remaining cerebral cortical mantle).
• Ocular Signs:
  • Setting Sun Sign (Sunset Phenomenon): Present bilaterally at rest; both globes deviated downwards exposing the upper sclera.
  • Pupillary Reflexes: 2.5 mm bilaterally, briskly reactive to light.
  • Fundoscopy: Pale optic disc with sharp margins (early secondary optic atrophy); no acute flaming papilledema.

Spine & Perineal Examination

• Spine: Well-healed, transverse $5\text{ cm}$ surgical scar in the lumbosacral region (L4–S1 level); no CSF leak, redness, fluctuant collection, or sinus tract.
• Perineum & Sphincters:
  • Patulous, lax anal sphincter with gaping anal orifice.
  • Anal Wink Reflex: Absent (pinprick around perianal S4–S5 dermatome fails to elicit reflex anal contraction).
  • Palpable distended bladder up to the umbilicus; gentle suprapubic pressure elicits expression of urine (overflow incontinence / lower motor neuron neurogenic bladder).
• Extremities: Symmetrical bilateral Talipes Equinovarus (Clubfoot) deformities (fixed ankle equinus, heel varus, forefoot adduction).

Systemic Examination

CNS Examination

1. Higher Mental Functions & Cranial Nerves

• Consciousness: Alert, responsive to visual stimuli; smiles and coos socially.
• Cranial Nerves:
  • CN II: Fixates and tracks bright objects within visual field; setting sun sign present.
  • CN III, IV, VI: Extraocular movements full except for limited spontaneous upward gaze.
  • CN VII: Symmetrical smile and facial movements; no facial palsy.
  • CN IX, X, XII: Good sucking and swallowing; normal cry; no stridor or tongue fasciculations.

2. Motor System Examination

3. Sensory System

• Pain sensation (pinprick withdrawal): Intact in upper limbs and trunk down to the L2 dermatome; absent / anaesthetic below the L4 dermatome (saddle area, legs, and feet).

other systems

• Respiratory System: Vesicular breath sounds bilaterally; clear chest; no stridor or wheeze.
• Cardiovascular System: Heart sounds S1, S2 heard normally; no murmurs.
• Abdomen: Soft; distended urinary bladder palpable; liver 1.5 cm below costal margin (soft, smooth); spleen not palpable.

Summary

Differential Diagnosis

Investigation Protocol & Diagnostic Workup

flowchart TD
    A["Suspected Hydrocephalus with MMC"] --> B["1. Neurosonogram (Transfontanellar USG)"]
    B --> C["Dilated Lateral & Third Ventricles (Evans Index > 0.3)"]
    C --> D["2. MRI Brain & Whole Spine (with CISS / FIESTA sequences)"]
    D --> E["Chiari II: Tectal Beaking, Tonsillar Herniation, Hydrocephalus, Tethered Cord"]
    A --> F["3. Renal & Bladder Ultrasound (Hydronephrosis, Trabeculated Bladder)"]
    A --> G["4. Urodynamic Studies (Detrusor-Sphincter Dyssynergia / High-Pressure Bladder)"]

1. Neuroimaging (First-Line Diagnostic Standard)

• Transfontanellar Neurosonography (NSG):
  • Non-invasive bedside screening through the open anterior fontanelle.
  • Measures Anterior Horn Width (AHW), Thalamo-Occipital Distance (TOD), and Evans Index: $$\text{Evans Index} = \frac{\text{Maximum width of frontal horns}}{\text{Maximum internal diameter of skull}}$$ An Evans Index $>0.30$ establishes significant ventriculomegaly.
• MRI Brain and Whole Spine with 3D CISS / FIESTA Sequences:
  • Brain Findings (Chiari II Malformation): Beaking of the midbrain tectum, downward herniation of the cerebellar vermis and fourth ventricle through the foramen magnum, hypoplastic tentorium, agenesis/thinning of corpus callosum, and severe lateral and third ventricular dilatation.
  • Spine Findings: Level of placode closure, low-lying conus medullaris (tethered cord below L2), syrinx / hydromyelia.

2. Urological & Renal Evaluation

• Ultrasound Kidneys, Ureters, and Bladder (KUB): Essential baseline screening for bilateral hydroureteronephrosis, cortical thinning, post-void residual volume, and thickened trabeculated bladder wall.
• Micturating Cystourethrogram (MCU / VCUG): Identifies Vesicoureteral Reflux (VUR, Grades I–V) and bladder neck incompetence.
• Urodynamic Studies (UDS): Quantifies detrusor leak point pressure (DLPP $>40\text{ cm H}_2\text{O}$ carries high risk of upper tract renal deterioration).

Management Plan

flowchart LR
    A["Multidisciplinary MMC & Hydrocephalus Care"] --> B["1. Neurosurgical CSF Diversion (VP Shunt / ETV)"]
    A --> C["2. Urological Management (CIC & Anticholinergics)"]
    A --> D["3. Orthopedic Care & Clubfoot Splinting"]
    A --> E["4. Recurrence Prevention (Folic Acid)"]

1. Neurosurgical Management of Hydrocephalus

• Ventriculoperitoneal (VP) Shunt Surgery (Gold Standard):
  • Placement of a silicone catheter system with a unidirectional pressure-regulating valve connecting the right frontal (Kocher's point) or parietal horn to the peritoneal cavity.
  • Selection of Valve: Medium-pressure or programmable differential-pressure valve with anti-siphon device.
• Endoscopic Third Ventriculostomy with Choroid Plexus Cauterization (ETV/CPC):
  • Alternative surgical procedure in selected centers for non-communicating hydrocephalus to avoid permanent prosthetic shunt dependency.

2. Urological Management (Preservation of Renal Function)

• Clean Intermittent Catheterization (CIC):
  • Initiate sterile/clean catheterization via urethra every 4 to 6 hours using an appropriate French size (6–8 Fr) catheter to ensure complete bladder emptying and maintain low intravesical pressure.
• Anticholinergic Pharmacotherapy:
  • Oral Oxybutynin: $0.1\text{–}0.2\text{ mg/kg/dose}$ 2 to 3 times daily to relax the hyperreflexic detrusor muscle and prevent high-pressure vesicoureteral reflux.
• Prophylactic Antibiotics: Low-dose Trimethoprim ($1\text{–}2\text{ mg/kg/day}$) or Nitrofurantoin for recurrent urinary tract infections with VUR.

3. Orthopedic & Physical Rehabilitation

• Ponseti Method for Talipes Equinovarus:
  • Serial corrective plaster casting followed by percutaneous Achilles tenotomy and Mitchell abduction splinting.
• Physiotherapy & Mobility Aids:
  • Ankle-Foot Orthoses (AFOs) and standing frames to encourage upright standing and prevent hip dislocations.

4. Recurrence Prevention & Preconceptional Folic Acid

• Preconceptional Folic Acid Supplementation for Mother:
  • In women with a previous child affected by a Neural Tube Defect, the recommended preconceptional dose is $4.0\text{–}5.0\text{ mg/day}$ orally (10 times the standard $0.4\text{ mg}$ dose), starting at least 1 month prior to conception and continued throughout the first trimester (reduces recurrence risk by $\ge 70\%$).
• Prenatal Screening in Future Pregnancies:
  • Maternal Serum Alpha-Fetoprotein (MSAFP) at 15–18 weeks; High-resolution targeted anomaly ultrasound scan (TIFFA) at 18–20 weeks (lemon sign and banana sign).