Recognizing the Signs: From Birth through Childhood

The journey to a diagnosis of Pituitary Stalk Interruption Syndrome (PSIS) often looks very different from one family to the next. Because the pituitary gland controls so many different functions, the symptoms can appear as a sudden emergency in a newborn or as a slow, subtle change in a school-aged child ^[1]. Understanding these signs can help you make sense of your child’s medical history and prepare for the road ahead.

Early Warning Signs in the Newborn Period

For many families, the first clues appear shortly after birth. However, because these symptoms are often common in newborns for other reasons, they are frequently attributed to “normal” infant struggles at first ^[2].

• Hypoglycemia (Low Blood Sugar): This is one of the most serious early signs. A baby with PSIS may have dangerously low blood sugar because they lack the hormones (like growth hormone or cortisol, the stress hormone) that help keep sugar levels stable ^[3]. In severe cases, this can lead to jitteriness, lethargy, or even seizures, which often result in a NICU stay ^[2][4].
• Cholestasis and Jaundice: While mild jaundice is common in newborns, babies with PSIS can develop cholestasis, a condition where bile doesn’t flow properly from the liver. Cholestasis (conjugated hyperbilirubinemia) requires prompt medical evaluation and is a “red flag” that distinguishes it from ordinary newborn jaundice ^[5].
• Genital Findings: In baby boys, a lack of “signaling” hormones during development can result in a micropenis (a very small penis) or cryptorchidism (undescended testes) ^[6]. These are often the earliest physical “red flags” that the pituitary isn’t working correctly.
• Feeding Difficulties: Some babies may have a “weak suck,” appear very floppy (hypotonia), or simply be too sleepy to feed well ^[2].

Signs in Childhood and Adolescence

If PSIS isn’t caught in the first few weeks of life, it usually becomes apparent later through changes in physical growth and development.

• Severe Growth Deceleration: This is the most common reason for diagnosis in older children ^[1]. You might notice that your child has “flatlined” on their growth chart or that they are staying the same clothes size for a year or more. They often appear much shorter than their siblings or classmates ^[7].
• Delayed or Absent Puberty: As a child reaches the teenage years, the pituitary is supposed to signal the body to begin puberty. In PSIS, these signals may be weak or missing entirely. A teenager might not show any signs of pubertal changes, or puberty may start and then completely stall ^[7].
• Increased Fatigue: Children with multiple hormone deficiencies may tire more easily than their peers or seem to have less “stamina” for physical activities ^[2].

The Burden of Deficiency: A Spectrum of Impact

Not every child with PSIS lacks the same hormones. Doctors use the term endocrine phenotype to describe the specific “recipe” of hormone shortages a child has. This can change over time, which is why ongoing monitoring is so important.

• Isolated vs. Multiple Deficiencies: Some children start with only an Isolated Growth Hormone Deficiency (IGHD), meaning only their growth is affected at first ^[8]. Others have Multiple Pituitary Hormone Deficiencies (MPHD), where several “lines” of hormones (like those for the thyroid, adrenal glands, and growth) are all low ^[3].
• Accumulating Deficiencies: While the congenital brain structure does not actively worsen, the clinical hormone deficiencies may appear over time ^[8]. A child who only needs growth hormone at age five might develop a need for thyroid or puberty hormones by age twelve. Cohort studies show that roughly 60% of children with PSIS eventually developed additional deficiencies, especially if their pituitary stalk was completely missing on the MRI (though individual risk varies based on follow-up and anatomy) ^[8].

Because the symptoms can be so varied, the “path to diagnosis” can take anywhere from a few days to several years. Regardless of when your child was diagnosed, the focus now is on replacing what is missing. (For information on what to do during illnesses or emergencies related to these symptoms, please refer to the Managing Emergencies page.) ^[2][9]