Presenting History
In infants presenting with suspected Congenital Hypothyroidism, elicit the neonatal timeline of jaundice, feeding behavior, activity level, bowel habits, cry character, and cranial fontanelle size.
- Prolonged Jaundice & Delayed Meconium:
- Did the physiological jaundice fail to resolve by 2-3 weeks and persist beyond 4-6 weeks of life?
- Was the first meconium passed after 48 hours of life?
- Lethargy & Feeding Fatigue:
- Is the infant excessively sleepy, placid, rarely crying for feeds, sleeping $>18\text{ hours/day}$?
- Is sucking weak, slow, with frequent choking and prolonged feeds ($>45\text{ minutes}$)?
- Voice Change (Hoarse Cry):
- Is the baby's cry characteristically low-pitched, coarse, throaty, and raspy?
- Bowel Habits & Abdominal Swelling:
- Is there obstinate constipation (passing hard pellet-like stools once every 3-5 days)?
- Has an umbilical swelling appeared or enlarged?
- Temperature & Skin Changes:
- Are the extremities constantly cold to touch? Is the skin dry, coarse, scaly, or mottled?
Negative History (3C 1D Framework)
| Category | Pertinent Negative Question | Rationale / Significance |
|---|---|---|
| Causes | Maternal Thyroid Disease: No maternal goiter, Hashimoto thyroiditis, or antithyroid drug intake (carbimazole/PTU). Iodine Exposure: No maternal topical povidone-iodine exposure or severe iodine deficiency. Consanguinity: Inquire regarding parental consanguinity. | Transplacental maternal TRBAb or antithyroid medications cause transient congenital hypothyroidism. Perinatal iodine excess induces Wolff-Chaikoff effect. Consanguinity strongly favors autosomal recessive dyshormonogenesis (TPO mutation). |
| Complaints (Differentiating) | Down Syndrome: No upslanting palpebral fissures, epicanthal folds, simian crease, or sandal gap. Hirschsprung Disease: No bilious vomiting or explosive relief upon digital rectal examination. | Down syndrome also features hypotonia and macroglossia, but has distinctive facies. Differentiates aganglionic megacolon from hypothyroid hypomotility constipation. |
| Complications | Hypothermia / Sepsis: No severe hypothermia ($<35.0^\circ\text{C}$), sclerema, or shock. Cardiac Failure: No tachypnea, cyanosis, or pericardial effusion signs. | Severe untreated hypothyroidism precipitates hypothermic myxedema collapse. Untreated congenital hypothyroidism can cause cardiomegaly and pericardial transudates. |
| Differentials | Beckwith-Wiedemann: No macrosomia, hemihypertrophy, or earlobe creases. Inborn Errors of Metabolism: No episodic encephalopathy, hyperammonemia, or metabolic ketoacidosis. | BWS also has macroglossia and umbilical hernia, but presents with macrosomia and hypoglycemia. Differentiates metabolic crisis from endocrine lethargy. |
Other Relevant History
- Newborn Screening (NBS): Was a heel-prick dry blood spot TSH performed at 48-72 hours of life? What was the reported TSH level?
- Gestational Age & Delivery: Post-term gestation ($>40-41\text{ weeks}$) and high birth weight are common in congenital hypothyroidism.
- Family History & Pedigree: Consanguinity, previous sibling neonatal deaths or goiter.
History Summary
"Baby/Master/Miss `Patient Name`, a `Age in weeks/months` old `male/female` infant, `Birth Order` born of a `consanguineous/non-consanguineous` marriage from `City, State`, presented with prolonged neonatal jaundice lasting up to `Duration in weeks`, lethargy, poor feeding, hoarse raspy cry, obstinate constipation, dry cold skin, and umbilical swelling, with `positive/negative` family history of sibling death/goiter, in the absence of bilious vomiting, seizures, or maternal thyroid disease.
In view of the constellation of prolonged jaundice, macroglossia, obstinate constipation, and somnolence, I would like to consider a provisional diagnosis of Primary Congenital Hypothyroidism, most likely Thyroid Dysgenesis / Dyshormonogenesis, presenting in late clinical stage with active neuro-developmental risk, requiring immediate venous thyroid profile and Levothyroxine initiation."
General & Head-to-Toe Examination
- Behavioral State: Prechtl state (drowsy, sluggish wakefulness, dull facies).
- Vitals:
- Heart Rate: Assess for resting bradycardia (HR $<100-110\text{ bpm}$ in young infants).
- Temperature: Assess for hypothermia (axillary $<36.0^\circ\text{C}$).
- Respiratory rate, blood pressure.
- Anthropometry: Length (stunting), Weight, Head Circumference.
- Craniofacial & Myxedematous Stigmata:
- Facies: Coarse, puffy facies with broad flat nasal bridge and periorbital edema.
- Mouth: Macroglossia (large hypertrophied tongue protruding between lips).
- Fontanelles & Sutures:
- Anterior Fontanelle: Widely open ($>3 \times 3\text{ cm}$).
- Posterior Fontanelle: Open ($>0.5\text{ cm}$ beyond birth is pathognomonic).
- Neck: Palpate for goiter (thyroid enlargement favors dyshormonogenesis; empty thyroid bed favors dysgenesis/agenesis).
- Skin: Dry, rough, scaly skin; cutis marmorata (mottling).
Systemic Examination
Abdomen
- Symmetrically distended; Umbilical Hernia (measure ring defect, check reducibility); divarication of recti; palpable soft liver; sluggish bowel sounds.
Central Nervous System (CNS)
- Generalized Hypotonia: "Frog-leg" posture, complete head lag on pull-to-sit, inverted-U on ventral suspension, scarf sign crosses midline effortlessly.
- Reflexes: Deep tendon reflexes with prolonged relaxation phase (Woltman sign).
- Developmental Assessment: Gross motor head control and social smile delay.
Cardiovascular System
- Distant, muffled heart sounds; bradycardia; no murmurs.
Final Summary & Diagnosis
"A `Age in weeks/months` old `male/female` infant presenting with prolonged jaundice, feeding fatigue, hoarse cry, constipation, and developmental delay, with examination revealing resting bradycardia (`HR in bpm`), hypothermia, macroglossia, widely open anterior and posterior fontanelles, umbilical hernia, `palpable goiter / empty thyroid bed`, and severe generalized hypotonia.
My final diagnosis is Primary Congenital Hypothyroidism, most likely Thyroid Dyshormonogenesis / Dysgenesis, presenting in active hypothyroid state with developmental delay, requiring immediate high-dose oral Levothyroxine therapy (10-15 mcg/kg/day)."