A 35-year-old woman presented to her primary care physician’s office with constant dull pain in the lower abdomen of one month’s duration. There was no history of fever, nausea, vomiting, diarrhea, constipation, or weight loss. Her menstrual cycles were regular. She had been receiving treatment for infertility for last 18 months. On physical examination, she had mild tenderness in the lower abdomen and pelvis. The rest of the physical examination was normal. A pregnancy test came back negative.
Routine blood tests were obtained and results were within normal range. An ultrasound of the pelvis was ordered; findings are presented in Figures 1 and 2.
What do the ultrasound images reveal? What’s your diagnosis?
Answer: Ovarian hyperstimulation syndrome
Ultrasound findings revealed marked enlargement of both ovaries, each showing multiple peripheral enlarged cysts with stromal ovarian tissue in the center creating a "wheel spoke" pattern.
Ovarian hyperstimulation syndrome (OHSS) is a rare complication of ovarian hyperstimulation caused by assisted reproduction technology and other treatments for infertility. OHSS is characterized by ovarian enlargement that results from the presence of multiple ovarian cysts and an acute fluid shift into the extravascular space. The pathogenesis involves increased ovarian angiogenesis in response to gonadotropins and amplified luteinizing hormone response that leads to increased vascular permeability in ovarian vessels.
Ultrasound shows significantly enlarged bilateral ovaries, often measuring >12 cm in size. In the present case, the right ovary measured 17.3 cm and the left 15.9 cm in size. Multiple large cysts are seen surrounding the ovarian stroma creating the the appearance of spokes coming from the center of a wheel.1,2
Based on clinical manifestations, biochemical and ultrasound findings, OHSS are classified as3,4:
Mild: characterized by bilateral ovarian enlargement with multiple follicular and corpus luteum cysts, abdominal distention and discomfort, mild nausea, and less frequently, vomiting and diarrhea. There are no biochemical abnormalities.
Moderate: The clinical features of moderate OHSS include those of mild OHSS plus ultrasonographic evidence of ascites. Laboratory features include a hematocrit above 41 percent and white blood cell concentration (WBC) above 15,000/mL, with hypoproteinemia.
Severe: Hypovolemia, oliguria or anuria, and intractable nausea and/or vomiting are frequently present. Creatinine levels are above 1.6 mg/dL. Abnormal LFT, white blood cell count >25,000/mL, and electrolyte imbalance (hyponatremia, hyperkalemia) are present. Hemoconcentration increases the risk for thromboembolism.4
Critical: Function of vital organs and systems is seriously compromised.
Mild and moderate OHSS are self limiting and resolve with supportive measures. Severe and critical cases require in-hospital treatment.3
The prevalence of assisted reproduction is increasing so that all clinicians, including primary care practitioners, should be familiar with the clinical presentation of OHSS.
1. Baron KT, Babagbemi KT, Arleo EK, et al. Emergent complications of assisted reproduction: expecting the unexpected. Radiographics. 2013;33:229-244.
2. Rankin RN, Hutton LC. Ultrasound in ovarian hyperstimulation syndrome. J Clin Ultrasound. 1981;9:473-476.
3. Myrianthefs P, Ladakis C, Lappas V, et al. Ovarian hyperstimulation syndrome (OHSS): diagnosis and management. Intensive Care Med. 2000; 26:631-634.
4. Ironside EC, Hotchen AJ. Ovarian hyperstimulation syndrome, the master of disguise? Case Rep Emerg Med. 2015;2015:510815. doi: 10.1155/2015/510815. Epub 2015 Feb 22.