Horner Syndrome in Children

Horner's SyndromeDespite what some may think, medical school wasn’t that long ago for me (stop laughing people!). I remember learning by making associations. Rash on “palms and soles” meant to think of syphilis. Horner Syndrome meant to think of a pancoast tumor. Certainly those associations can prove to be helpful later in your clinical days / daze, but are not always appropriately associated with respect to children. Let’s take a minute to make a new association for Horner Syndrome in Children:


Horner Syndrome: Basics

  • Horner Syndrome
    • Manifestation of autonomic dysfunction of the sympathetic nervous system. [Miquel, 2017]
      • Due to disruption of the oculosympathetic pathway.
    • Oculosympathetic pathway is a 3rd order pathway (has three neurons)
      • 1st (CNS) – from Hypothalmus to lower cervical or upper thoracic spinal cord
      • 2nd (Pre-ganglionic) – from spinal cord to superior cervical ganglion
        • Travels via sympathetic chain
        • Ascends in soft tissues of the neck
        • Vulnerable along this route
      • 3rd (Post-ganglionic) – forms a plexus around the carotid artery and finally innervates the muscles of the iris and the upper and lower eyelids.
  • Horner Syndrome, classically, => Ptosis, Miosis, and Anhidrosis
    • Ptosis may be subtle. [Cahill, 2015]
      • Determined by distance from upper eyelid to the mid pupil.
    • Anisocoria can also be difficult to discern. [Cahill, 2015]
      • The side with ptosis is the abnormal pupil (whether larger or smaller).
      • Assess the pupils in both a bright and dark environment.
        • The two extreme environments should accentuate either an abnormally constricted or an abnormally dilated pupil.
        • If the difference between the two pupils remains constant, regardless of the environment, then this may represent physiologic anisocoria.
        • Anisocoria > 1.3 mm is unlikely to be physiologic in a child. [Suh, 2016]
    • Anhidrosis is very difficult to detect, particularly in the ED.
      • Do not rely on this sign.
      • 3rd order nerve lesions do NOT typically cause anhidrosis.
  • Horner Syndrome can be Congenital or Acquired [Cahill, 2015]
    • Congenital
      • Present in early infancy and persists into early childhood.
      • Iris heterochromia can be seen later.
      • Typically involves the 3rd order neuron, from stretching the carotid sheath.
      • Most common identifiable cause of pediatric Horner Syndrome = Birth Trauma
    • Acquired 
      • Many cases are idiopathic. [Mahoney, 2006]
      • Surgical procedures can lead to sympathetic change injury. [Miquel, 2017; Nasser, 2015; Baird, 2009]
      • Biggest concerns for evaluation of new-onset Horner Syndrome is Neuroblastoma. [Miquel, 2017]


Ptosis: An Approach

Below are several important considerations when evaluating ptosis. [Cahill, 2015]

  • Is there trauma? 
  • Is there periorbital rash or erythema?
  • Is there restricted movement of the eye?
    • On same side as ptosis => CN III palsy (usually affected eye is positioned down and out)
    • Involving other eye => broad Ddx including Mysathenia, Lyme, and Brainstem lesions
  • Is there Anisocoria?
    • Pupil larger on side with ptosis => CN III palsy
    • Pupil smaller on side with ptosis => Horner Syndrome


Horner Syndrome: Kids vs Adults

  • Adults most often have either 1st or 3rd order neurons affected. [Cahill, 2015]
    • Think:
      • Stroke
      • CNS masses
      • Carotid Artery Aneurysms / Dissections
    • Rarely have 2nd order neuron involvement:
      • Apical tumor (ex, pancoast tumor)
  • Children more often have 2nd order / preganglionic neurons affected. [Cahill, 2015]
    • Injuries or masses in the neck are more prevalent than CNS disease.
      • Birth Trauma [Jeffery, 1998]
      • Mediastinal Masses
      • Benign Neck Masses (ex, lymphadenopathy)
      • Infectious Masses (ex, Tuberculosis)
    • One important condition to keep in mind is Neuroblastoma.
      • Unusual, but is the most significant treatable cause of Horner Syndrome in children. [Cahill, 2015]
      • 2nd most common malignant solid tumor in pediatric patients.
    • Evaluation:
      • No consensus recommendations exist. [Cahill, 2015]
      • Obtain thorough birth history and surgical history.
      • Thorough physical exam looking specifically for neck or abdominal masses.
      • Obtain spot urine catecholamine metabolites
        • Homovanillic acid and vanillylmandelic acid
        • Cannot rule-out neuroblastoma with just these studies alone. [Mahoney, 2006]
      • Imaging of the neck and chest… and maybe head and abdomen. [Kadom, 2015]
        • If story is consistent with forceful manipulation of an infant’s neck during delivery, may be able to avoid extensive imaging, but otherwise need to look for neuroblastoma. [Jeffery, 1998]
        • CT imaging is  sensitive for neuroblastoma.
        • MRI does have superior resolution of paravertebral structures. [Mahoney, 2006]
        • Given difference between adults and children, do not typically need to image the vasculature in children. [Cahill, 2015]
        • Based on your work environment and resources, these images may best be obtained in the inpatient setting vs the ED.


Moral of the Morsel

  • Children do get Horner Syndrome, but for different reasons than adults.
  • Birth Trauma leads the way. Congenital causes are likely to be mechanical stress placed on the neck/carotid sheath.
  • New onset Horner Syndrome? Gotta think of neuroblastoma.



Miquel J1, Piyaraly S2, Dupuy A3, Cochat P4, Phan A4. Congenital Cases of Concomitant Harlequin and Horner Syndromes. J Pediatr. 2017 Mar;182:389-392. PMID: 28038766. [PubMed] [Read by QxMD]

Suh SH, Suh DW, Benson C. The Degree of Anisocoria in Pediatric Patients With Horner Syndrome When Compared to Children Without Disease. J Pediatr Ophthalmol Strabismus. 2016 May 1;53(3):186-9. PMID: 27224954. [PubMed] [Read by QxMD]

Cahill JA1, Ross J2. Eye on children: acute work-up for pediatric Horner’s syndrome. case presentation and review of the literature. J Emerg Med. 2015 Jan;48(1):58-62. PMID: 25281181. [PubMed] [Read by QxMD]

Nasser BA1, Mesned A1, Moazamy YE1, Kabbani MS2. Horner’s syndrome after paediatric cardiac surgery: case report and review of the literature. Cardiol Young. 2015 Mar;25(3):569-72. PMID: 24717921. [PubMed] [Read by QxMD]

Kadom N1, Rosman NP, Jubouri S, Trofimova A, Egloff AM, Zein WM. Neuroimaging experience in pediatric Horner syndrome. Pediatr Radiol. 2015 Sep;45(10):1535-43. PMID: 25832988. [PubMed] [Read by QxMD]

Baird R1, Al-Balushi Z, Wackett J, Bouchard S. Iatrogenic Horner syndrome after tube thoracostomy. J Pediatr Surg. 2009 Oct;44(10):2012-4. PMID: 19853764. [PubMed] [Read by QxMD]

Mahoney NR1, Liu GT, Menacker SJ, Wilson MC, Hogarty MD, Maris JM. Pediatric horner syndrome: etiologies and roles of imaging and urine studies to detect neuroblastoma and other responsible mass lesions. Am J Ophthalmol. 2006 Oct;142(4):651-9. PMID: 17011859. [PubMed] [Read by QxMD]

Jeffery AR1, Ellis FJ, Repka MX, Buncic JR. Pediatric Horner syndrome. J AAPOS. 1998 Jun;2(3):159-67. PMID: 10532753. [PubMed] [Read by QxMD]

Sean M. Fox
Sean M. Fox

I enjoy taking care of patients and I finding it endlessly rewarding to help train others to do the same. I trained at the Combined Emergency Medicine and Pediatrics residency program at University of Maryland, where I had the tremendous fortune of learning from world renowned educators and clinicians. Now I have the unbelievable honor of working with an unbelievably gifted group of practitioners at Carolinas Medical Center. I strive every day to inspire my residents as much as they inspire me.

Articles: 583


  1. Confusion in the diagnostic process may arise because some patients with Horner syndrome do not exhibit the classic findings of simultaneously occurring miosis and mild ptosis. When that is the case, the diagnosis may be missed and essential life-saving treatment not rendered.

Comments are closed.