“She Hasn’t Started Her Periods”

Patient Presentation
A 13.5 year-old female came to clinic as she and her mother were very concerned about menarche initiation. The past medical history and record reviewed showed at 11 years 4 months she was Tanner II for breast and pubic hair development, and at 12 years 8 months she was Tanner III for both. She had no known chronic health problems and during a private interview she denied any sexual activity.

The family history revealed that her mother had menarche at age 13, and also had no abnormal gynecological or obstetric problems. The patient had a younger sister who was age 10 years. Her father’s pubertal history was unknown. There was a maternal aunt with “early onset” hypothyroidism. The review of systems was negative for pelvic or abnormal pain, large changes in weight, cold/heat intolerance, constipation, headache, visual changes, or galactorrhea. She also denied any abnormal eating patterns or excessive exercise.

The pertinent physical exam showed normal vital signs with her weight and height around the 50%. She had increased her height by approximately 9 cm in the past year. She was Tanner IV for breast and pubic hair. Her external genital examination showed normal structures including an open hymenal ring.

The diagnosis of a healthy female with likely normal progression of puberty was made. She and her mother were quite anxious and wanted testing. Her pregnancy test was negative, and hormonal levels were normal for age/pubertal stage. The patient’s clinical course 3 months later showed some spreading of pubic hair. One month later her mother sent a message to the office that menses had started. By age 15 years 0 months, she had normal menstrual cycling.

Discussion
There is a wide range of normal pubertal development and “normality” is a common question that both patients and families have. Breast budding and testicular enlargement onset can be less obvious but menarche is usually more obvious and therefore families become concerned when menarche doesn’t occur at the time they expect. Delayed puberty is onset of secondary sexual characteristics occurring > 2 standard deviations from the mean for gender, which in females is age 13 for breast development and 14 years for testicular development in males. Pubertal onset range is usually 8-13 years in females and 9-14 years in males.

Primary amenorrhea is “…no period by age 14 years in the absence of growth or development of secondary sexual characteristics, or no period by age 16 regardless of the presence of normal growth and development with the appearance of secondary sex characteristics.” Primary amenorrhea initial evaluation usually includes history, physical examination, along with pregnancy testing, thyroid stimulating hormone, follicle stimulating hormone, and luteinizing hormone testing. Bone age may also be considered especially if constitutional delay is being considered. Pelvic ultrasound to determine if there is a uterus and ovaries or other anatomic abnormalities can also assist in the early evaluation. Karyotyping, testosterone levels, and imaging of the brain/pituitary/hypothalamus may also be needed as part of the evaluation. Consultation with endocrinology and/or gynecology can also be helpful for both clinicians and families.

Learning Point
The differential diagnosis of primary amenorrhea includes:
(Note: percentages do not include delayed puberty and pregnancy)

  • Constitutional delay of puberty
  • Pregnancy
  • Anatomic outflow tract (~20% of causes)
    • Imperforate hymen
    • Mullerian agenesis
    • Transverse vaginal septum
    • Cervical agenesis
    • Androgen insensitivity syndrome
  • Ovarian dysfunction (~50% of causes)
    • Chromosomal abnormalities
      • Turner syndrome – very common cause, most common individual cause
        • Fragile X variation
        • Swyer’s syndrome
      • Inflammatory disorders
      • Chemotherapy/radiotherapy
      • Polycystic ovarian syndrome
  • Pituitary dysfunction (pituitary and hypothalamic dysfunction ~ 25% of causes)
    • Pituitary tumors
      • Hyperprolactinoma
      • Adenomas
      • Glioma
      • Meningiomas
    • Diabetes insipidus
    • Empty sella syndrome
    • Pituitary infarction
  • Hypothalamic dysfunction
    • Functional amenorrhea – very common cause
      • Severe or chronic illness
      • Stress
      • Disordered eating
      • Weight loss such as exercise
    • Kallman syndrome
    • Miscellaneous infiltrative or inflammatory disorders
      • Brain tumor
      • Cranial radiation
      • Syndromes
  • Other (~ 5% of causes)
    • Hyperthyroidism
    • Hypothyroidism
    • Diabetes, uncontrolled
    • Androgen use, exogenous
    • Congenital adrenal hyperplasia

Questions for Further Discussion
1. What are causes of secondary amenorrhea? A review can be found here
2. Patients with Turner’s syndrome can have what types of problems? A review can be found here
3. What are potential causes of linear growth delay? A review can be found here

Related Cases

To Learn More
To view pediatric review articles on this topic from the past year check PubMed.

Evidence-based medicine information on this topic can be found at SearchingPediatrics.com and the Cochrane Database of Systematic Reviews. Information prescriptions for patients can be found at MedlinePlus for this topic: Menstruation

To view current news articles on this topic check Google News.

To view images related to this topic check Google Images.

To view videos related to this topic check YouTube Videos.

Heiman DL. Amenorrhea. Primary Care: Clinics in Office Practice. 2009;36(1):1-17. doi:10.1016/j.pop.2008.10.005

Kanabolo D, Rodriguez J, Waggoner D, et al. A Phenotypic Female Adolescent with Primary Amenorrhea and Dysmorphic Features. Pediatr Ann. 2019;48(12):e495-e500. doi:10.3928/19382359-20191118-02

Garg A, Vash-Margita A, Simoni MK. Abnormal Puberty and Amenorrhea: A Review. Pediatr Ann. 2025;54(9):e294-e301. doi:10.3928/19382359-20250707-03

Marsh CA, Grimstad FW. Primary amenorrhea: diagnosis and management. Obstet Gynecol Surv. 2014;69(10):603-612. doi:10.1097/OGX.0000000000000111

Author
Donna M. D’Alessandro, MD
Professor of Pediatrics, University of Iowa

Why Did Meningitis B Vaccine Take So Long to Develop?

Patient Presentation
A 17-year-old female came to clinic for her health maintenance visit. She was a senior in high school and was planning on living in the dormitories when she starts college the following year. There were no health concerns. The pertinent physical exam revealed a healthy female with normal vital signs and normal physical examination.

The diagnosis of a healthy female was made. “I recommend that you get the Meningitis B vaccine today. It helps to protect against a meningitis which is a bad brain infection. It can occur in group settings like dorms so we recommend it for college-bound students. You’ll need one now and one again after at least 6 months,” the pediatrician recommended. “Didn’t I already get the meningitis vaccine last year?” she asked. “Right. You did but that is a different vaccine. That one is for meningitis groups A,C, W and Y. Meningitis B is different, and was developed differently, so we do it separately. There is a combination vaccine with all 5 types in it, but I don’t have that one. There’s been some problems with insurances paying for the combination. Your insurance will pay for the separate Meningitis B vaccine. What questions do you have about it or meningitis?” he went on. After discussion with her and her parent, she agreed to all recommended routine health surveillance including HIV screening and all vaccines.

Discussion
Neisseria meningitidis is a major cause of morbidity and mortality including pneumonia, septicemia and meningitis. There are high case fatality and serious life-long complications for those that survive. There are 12 serotypes but A, B, C, W, X and Y cause almost all of the invasive meningococcal disease (IMD). The others are C, H, I, K, L, and Z. The epidemiology of which serotypes cause IMD is different geographically and changes over time. Most IMD cases are in children < 2 years of age, but in some countries there is also a small peak in late adolescence/early adulthood.

Crowded conditions especially when first exposed have a high risk of IMD including first year students in dormitories, military recruits and those exposed for events such as Hajj and Umrah pilgrimages. The Kingdom of Saudi Arabia requires vaccination against A,C,W,Y for these pilgrimages. Some health care providers will also recommend it for other global events such as the Olympics or World Cup Soccer because of crowded conditions. The 73rd World Health Assembly has approved a public health path to defeat meningitis by 2030.

Vaccines against A, C, W, and Y that are mainly used today are polysaccharide-conjugate vaccines.

Learning Point
Meningitis B vaccines “have been difficult to develop due to structural similarities of its capsular polysaccharide with human foetal neural cell adhesions modules, rendering it poorly immunogenic.” There was also the concern for inducing antoimmunity. It has taken more than 40 years to develop these effective vaccines.

In 2013, 4CMenB (Bexsero® from GSK) was approved again serotype B and started being used as part of the routine immunization schedule in the United Kingdom in 2015. It is a 4 component, recombinant, protein-based vaccine. In 2015, it was approved for use in the United states for 10-25 year olds. Since that time more countries are using it and another approved vaccine against serotype B, MenB-FHbp (Trumenba®, from Pfizer). PENMENVY® (from GSK) has serotypes A,B,C,W,Y antigens and was approved in February 2025 in the US.

The vaccines have been very effective including >80% effectiveness in infancy and protection lasting up to 3 years. They have been shown to be potentially effective against other serotypes, and in some studies to also be effective against nasal carriage. Protection is thought to be longer lasting in people > 5 years who receive the vaccine than those < 5 year olds. There is some data supporting additional protection against Neisseria gonorrhea as both organisms share some antigens.

Questions for Further Discussion
1. What meningococcal meningitis vaccines to you recommend and have available in your practice?
2. Where can you find vaccine schedules for other countries?
3. What are the different cerebrospinal fluid findings in different causes of meningitis? A review can be found here.
4. What causes encephalitis? A review can be found here.

Related Cases

To Learn More
To view pediatric review articles on this topic from the past year check PubMed.

Evidence-based medicine information on this topic can be found at SearchingPediatrics.com and the Cochrane Database of Systematic Reviews. Information prescriptions for patients can be found at MedlinePlus for these topics: Meningitis and Vaccine.

To view current news articles on this topic check Google News.

To view images related to this topic check Google Images.

To view videos related to this topic check YouTube Videos.

Rappuoli R, Pizza M, Masignani V, Vadivelu K. Meningococcal B vaccine (4CMenB): the journey from research to real world experience. Expert Review of Vaccines. 2018;17(12):1111-1121. doi:10.1080/14760584.2018.1547637

Garland JM. An Update on Meningococcal Vaccination. Rhode Island Medical Journal. Published online 2020.

Isitt C, Cosgrove CA, Ramsey ME, Ladhani SN, Success of 4CMenB in preventing meningococcal disease: evidence from real-world experience. Arch Dis Child 2020:105; 784-790.

Parikh SR, Campbell H, Bettinger JA, et al. The everchanging epidemiology of meningococcal disease worldwide and the potential for prevention through vaccination. Journal of Infection. 2020;81(4):483-498. doi:10.1016/j.jinf.2020.05.079

Meningitis. Accessed September 23, 2025. https://www.who.int/teams/immunization-vaccines-and-biologicals/diseases/meningitis

Author
Donna M. D’Alessandro, MD
Professor of Pediatrics, University of Iowa

Holiday Break

PediatricEducation.org is taking a holiday break and will return on January 5, 2026. We appreciate your continued patronage and wish everyone a happy and safe holiday season and all the best in the New Year.

In the meantime, please take a look at the different Archives and Curriculum Maps listed at the top of the page.

Happy Holidays,

Donna D’Alessandro and Michael D’Alessandro, curators.

If It’s Rare, Why Do We Talk About It So Much?

Patient Presentation
Pediatric residents and their attending pediatrician were discussing a new adolescent oncology patient admission. The teen was diagnosed with lymphoma after presenting with cough, fever and fatigue, and who had mediastinal lymphadenopathy. The attending remarked that lymphoma was common in this age group and also a common cause of anterior mediastinal tumors. “Remember your 4T’s, but thymoma is rare,” he said. “Then why do we always talk about it so much?” asked one of the residents. “I think that’s funny too. Thymoma is rare in kids, but more common in adults. I always think about tumors starting with what is the likely organ it is arising from, then what organs are around in that space like the mediastinum, lungs, abdomen etc. Then what else commonly would metastasize to this area, and then of course, there is always bones and soft tissues that can have tumors arise from them like sarcomas or lipomas or hemangiomas. In this case, the thymus is one of those organs in the area and therefore you have to think about it as a potential cause. Oh, I should also throw in, remember to include infections like tuberculosis or fungal infections infiltrating into tissues which can look like masses, or even diseases like sarcoid. Less common, but like thymomas you should think about potential causes, although we start to work up more likely causes first just because they occur more often. Rare diseases happen rarely but do happen. In this patient’s case, he has mediastinal adenopathy, but also other nodes that we were able to more easily biopsy and therefore make the lymphoma diagnosis,” he discussed.

Case Image

Figure 149 shows Hodgkin Lymphoma

Discussion
Thymomas are rare pediatric tumors. They can present at all ages from infancy to > 90 years but most occur in the 4th to 5th decades with 10% of thymomas diagnosed in those in the pediatric age range. There are approximately 80 cases of pediatric thymomas in the literature based on a 2022 comprehensive literature review spanning 1985-2020. In this and a 2014 review, males are more commonly affected than females in the pediatric age range, but in adults the genders are about the same percentage or have a slight female predominance.

Thymomas are associated with paraneoplastic processes including presentation with myasthenia gravis. Of pediatric patients with thymomas, 5-15% have been reported as having myasthenia gravis. For adult patients with a thymoma, 30% will develop myasthenia gravis. For those adult patients presenting with myasthenia gravis, 10% will have a thymoma. Overall most thymomas are generally indolent and often present for workup of another condition. However mass effect in the chest (e.g. cough, dyspnea, superior vena cava syndrome) can be a presentation especially in small children.

Learning Point
Thymic tumors include:

  • Thymoma
  • Thymic carcinomas

    Anterior mediastinal tumors are usually remembered by the 4T’s of thymoma, teratoma, thyroid and “terrible” lymphoma. Germ cell tumors and lymphomas are most common. The differential diagnosis includes:

    • Germ cell tumors such as teratomas and a variety of benign and malignant tumors of different cell types
    • Lymphoma – Hodgkin’s lymphoma is most common.
    • Thymic neoplasms – 15% with thymoma being the most common (about 4% of pediatric mediastinal tumors).
    • Aberrant thyroid tissue and goiter
    • Parathyroid adenoma
    • Hemangioma
    • Lipomas
    • Sarcomas

    Questions for Further Discussion
    1. Explain the function of the thymus?
    2. What is the name of the radiologic sign which shows the thymus on an infant chest radiograph?
    3. What are the different types of myasthenia gravis? A review can be found here.
    4. Describe the mediastinal spaces? A review can be found here.
    5. What are the most common pediatric tumors? A review can be found here.

    Related Cases

    To Learn More
    To view pediatric review articles on this topic from the past year check PubMed.

    Evidence-based medicine information on this topic can be found at SearchingPediatrics.com and the Cochrane Database of Systematic Reviews.

    Information prescriptions for patients can be found at MedlinePlus for these topics: Lymphoma, Thymus Cancer, and Myasthenia Gravis.

    To view current news articles on this topic check Google News.

    To view images related to this topic check Google Images.

    To view videos related to this topic check YouTube Videos.

    Yalcin B, Demir HA, Ciftci AO, et al. Thymomas in Childhood: 11 Cases From a Single Institution. Journal of Pediatric Hematology/Oncology. 2012;34(8):601-605. doi:10.1097/MPH.0b013e31825808e9

    Fonseca AL, Ozgediz DE, Christison-Lagay ER, Detterbeck FC, Caty MG. Pediatric thymomas: report of two cases and comprehensive review of the literature. Pediatr Surg Int. 2014;30(3):275-286. doi:10.1007/s00383-013-3438-x

    Rossi C, Zanelli M, Sanguedolce F, et al. Pediatric Thymoma: A Review and Update of the Literature. Diagnostics (Basel). 2022;12(9):2205. doi:10.3390/diagnostics12092205

    Myasthenia gravis and congenital myasthenic syndromes. In: Handbook of Clinical Neurology. Vol 195. Elsevier; 2023:635-652. doi:10.1016/B978-0-323-98818-6.00010-8

    Author
    Donna M. D’Alessandro, MD
    Professor of Pediatrics, University of Iowa