Case 42: Pain in early pregnancy

 

Case 42: Pain in early pregnancy

CASE 42: PAIN IN EARLY PREGNANCY

History

A 22-year-old woman attends the emergency department complaining of abdominal pain.

She is 7 weeks 4 days pregnant by certain menstrual dates. She had a normal vaginal delivery

at term 18 months ago. Her periods are usually regular every 27 days, with bleeding for 3–5

days. She has no previous gynaecological history. Her medical history involves mild asthma

and two episodes of cystitis.

The pain started suddenly two nights ago and is localized to the right iliac fossa with some

radiation down the right thigh. It is constant though worse on movement, so she has tended

to lie still. She has not taken any analgesia as she is uncertain whether this is safe for the

baby. She is always constipated and this is worse since she became pregnant. She has urinary

frequency but no dysuria or haematuria. She has a slightly reduced appetite but does not feel

feverish or sweaty.

Examination

Her temperature is 36.4°C, heart rate 90/min and blood pressure 96/58 mmHg. There are no

signs of anaemia and she feels warm and well perfused. She is slim and the abdomen is not

distended. There is focal tenderness on palpation of the right iliac fossa, with slight rebound

tenderness but no guarding. Rovsing’s sign is not present. Speculum examination is unremarkable. The uterus is bulky and retroverted with no cervical excitation. The right adnexa is

tender with a suggestion of ‘fullness’.

INVESTIGATIONS

Normal range for

pregnancy

Haemoglobin 12.1 g/dL 11–14 g/dL

Mean cell volume 89 fL 74.4–95.6 fL

White cell count 5.1×109/L 6–16×109/L

Platelets 223×109/L 150–400×109/L

C-reactive protein 5 mg/L <10 mg/L

Urinary pregnancy test: positive

Urinalysis: protein trace; blood negative; nitrites negative; leucocytes negative

Transvaginal ultrasound findings are shown in Figs. 42.1 and 42.2.

Figure 42.1 Transvaginal ultrasound scan showing a midsagittal view of the uterus.100 Cases in Obstetrics and Gynaecology

104

Questions

• What is the likely diagnosis and what are the differential diagnoses for the pain?

• How would you further investigate and manage this woman?

Figure 42.2 Transvaginal ultrasound scan showing a transverse view of the right adnexa,

demonstrating a haemorrhagic lesion measuring 73×64 mm.Case 42: Pain in early pregnancy

105

ANSWER 42

The ultrasound images show a single viable intrauterine pregnancy and haemorrhage into a

corpus luteal cyst.

! Differential diagnosis for pain in early pregnancy

• Corpus luteum

• Ectopic pregnancy

• Miscarriage

• Ovarian cyst

• Urinary tract infection

• Renal tract calculus

• Constipation

• Appendicitis

• Unexplained pain

Urinary tract infection or calculi are excluded by the urinalysis result. Constipation is

more likely to cause left-sided pain and the sudden onset of pain would perhaps be unusual.

Appendicitis should be considered but the lack of systemic features, the normal temperature,

white count and C-reactive protein are suggestive of this not being the diagnosis.

The corpus luteum is the cystic area that develops on the ovary at the ovulation site. It may

be solid, cystic or haemorrhagic and may vary in size. On colour Doppler ultrasound it

has a typical ‘ring of fire’ appearance, distinguishing it from other types of ovarian cyst.

In this case the ‘spider web’ or reticulated pattern of echoes within the cyst suggests that

it is haemorrhagic.

Management

Management is supportive with analgesia (paracetamol in the first instance followed by

codeine derivatives if necessary) and reassurance. There is no evidence that bleeding into

the corpus luteum adversely affects the pregnancy outcome. As the cyst is so large, it may be

sensible to repeat an ultrasound scan in 2–4 weeks to confirm resolution.

KEY POINTS

• A large or haemorrhagic corpus luteum is a common cause of early pregnancy

pain.

• Most women have no cause found for early pregnancy pain.

• Ectopic pregnancy must be excluded and non-gynaecological aetiology considered (constipation or urinary tract infection) in women with pain in early pregnancy.