Chapter 4 Medical student OSCE answers and discussion

STUDENT OSCE A

A1

Q1

Q2

Postnatal care

• Baby to the nursery

1 mark

20 marks total

Discussion

Diabetes affects 7.5% of the Australian adult population. Type I diabetes accounts for 10–15% of diabetes cases, with the rest being type II. These pregnancies are considered high risk due to the potential for complications for the mother and the fetus. A thorough knowledge of the risks (outlined in the ideal answers above) is expected, given the common nature of the condition.

A2

Q1

History

N.B. Should be brief (an obstetric emergency)

• 32-year-old primigravida with a singleton pregnancy

• No other medical or antepartum problems

• Induction of labour 16 hours ago with ARM and IV Syntocinon at 40 weeks gestation

• Contracting 4:10 strong for last 6 hours. Adequate progress on serial VEs

• Liquor clear. CTG normal (apart from no reactivity) throughout labour

• Used 1 dose of pethidine 100 mg 2 hours ago

• Normal cephalic delivery. No episiotomy cut. Duration of second stage 90 minutes

• A baby boy, with 1 and 5 minute Apgars of 8 and 9

½–1½ marks, depending on degree of detail about labour obtained

• Placenta appears whole. Third stage lasted 10 minutes

½ mark

• Bleeding heavily after delivery of placenta, fresh blood plus clots. Estimated blood loss 1 L

½ mark

• Medications: Syntocinon (10 units in 1 L N/saline, running at 120 mL/hour)

Examination/management

(Obstetric emergency, so carry on at same time)

• Call for more help (extra midwife/midwives, other doctors if available)

½ mark

• Assess patient’s conscious state – patient drowsy, but conscious and orientated

Assess haemodynamic state

• BP 100/60, PR 100, still active fresh bleeding, peripheries cool and sweaty

½ mark

Surgical management of uterine atony

• Call for help (experienced obstetrician if available), and take to operating theatre

• General anaesthetic (consider central venous line with anaesthetist)

• Examine in theatre: no lacerations or retained products, but continued bleeding

• Give prostaglandin F2α (0.25 mg injected via abdomen, by steadying fundus with non-injecting hand, into 4 quadrants of the uterus: maximum dose 1 mg)

1 mark, ½ without correct dose

Move to laparotomy (midline)

• Uterine artery ligation bilaterally

• Internal iliac artery ligation (bilateral)

• Consider B-Lynch suture

• Uterine packing or intrauterine tamponade balloon may be considered

½ mark for any of the above 4 options, to maximum 1½ marks

• If all else fails – hysterectomy (total or subtotal)

½ mark

N.B. An experienced obstetrician is able to attend. A hysterectomy, while considered, is not necessary to control the patient’s bleeding.

14 marks total for Q1

Discussion

Post-partum haemorrhage (PPH) is defined as the loss of greater then 500 mL of blood after delivery. It can be divided into primary (within 24 hours of delivery) and secondary (fresh bleeding after 24 hours but before 6 weeks post-delivery), which have different differential causes. The causes of secondary PPH include retained products (placenta or membranes), infection (chorioamnionitis/endometritis), subinvolution of the placental site, and rare causes such as aretrio-venous malformations. Our discussion will be limited to primary PPH, presented in this OSCE case.

Worldwide, PPH remains a major cause of maternal mortality and morbidity. The Western world has experienced a significant decline in maternal deaths from PPH due to preventative management (i.e. expectant management of the third stage of labour), as well as the ready availability of blood transfusions and oxytocic therapy. Nonetheless, deaths, as well as serious morbidity, due to post-partum haemorrhage still occur in Australia. In Victoria, for the years 1997–2003, there were 13 direct maternal deaths, of which five (38%) were attributed to PPH (two from amniotic fluid embolus and subsequent DIC, one from abruption causing uterine atony, one from uterine fibroids, and one from a retained placenta).

The incidence of primary PPH is estimated to be around 5% in most Australian obstetric units. It is a common obstetric complication, with potentially very serious consequences and, as such, students would be expected to complete their obstetrics rotation with a clear approach to management, and do well on this OSCE station.

The most common cause of primary PPH is uterine atony. The next two most common causes are retained products of conception and genital tract laceration (of the vagina or cervix). A rare cause of PPH is coagulopathy. A list of the risk factors for PPH are found in the answer to Q2.

The management of primary PPH is clearly laid out in the worked answer. It is important in this OSCE to state the obvious steps that would be taken in such an obstetric emergency, such as calling for help and giving oxygen by mask. If you do not say that you would take those steps the examiner cannot assume that you would automatically take them! In real life, as a resident or registrar in a tertiary hospital, there are well-trained staff who would do this automatically, but in the exam situation you are on your own and must demonstrate that you know how to handle an emergency.

A key approach to answering the management of a PPH is to divide it into clear sections, as laid out in the examiner’s ideal answer:

1. Call for help.

2. Initial assessment.

3. Initiate resuscitation.

4. Establish the most likely cause of PPH on history, examination and investigation.

5. Specific treatment of the cause of PPH.

If cause of PPH is vaginal/cervical laceration, then obviously suturing of the laceration should control the bleeding, and may need to be done in theatre (allows for both better visualisation, trained theatre nurse for assistance, and expert anaesthetic staff for ongoing resuscitation effort while bleeding brought under control).

If the PPH is due to a retained placenta or products, then a manual removal of placental tissue under adequate analgesia is required. In this case, premature administration of oxytocics may cause the cervix to clamp shut and make the procedure much more difficult. Conversely, a general anaesthetic may relax the uterine muscle, making it easier for the uterus to admit the hand for separation of the placenta from its attachment to the uterine wall.

Any identified coagulopathy should be corrected. Thrombocytopaenias will be corrected with platelet transfusion, while disseminated intravascular coagulation (DIC) will be corrected with fresh frozen plasma/cryoprecipitate and platelets. With coagulopathies, a haematologist (if available) should be consulted to help guide the appropriate administration of blood products.

Remember that the uterine atony is overwhelmingly the most common cause of primary PPH. It is the first, second and third cause on any list, to emphasise its importance. Management should start with medical treatment, and students are expected to know correct dosages. In an emergency there will often not be time to look up doses, so they must be memorised. Some of the potential side effects of the various oxytocics (not mentioned in the ideal answer as they do not relate to the presented case) are:

• Syntocinon – hypotension (especially as a large IV bolus), hyponatremia (due to antidiuretic effect), can cause ECG changes with IV boluses

• Ergometrine – nausea and vomiting, hypertension

• Misoprostol – bronchoconstriction (beware with asthma sufferers), fever, nausea

• Prostaglandin F2α – bronchoconstriction, nausea, vomiting, diarrhoea, fever, hypertension

All of the above oxytocics can cause cramping uterine pains as the uterus contracts.

Severe PPH can result in hypovolaemic shock, DIC and (rarely) Sheehan’s syndrome. Sheehan’s syndrome is avascular necrosis of the pituitary secondary to severe obstetric haemorrhage, and occurs in 1 in 10,000 deliveries. The patient has subsequent deficiency of the anterior pituitary hormones, manifested as failed lactation, amenorrhoea, hypothyroidism, and adrenocorticoid deficiency.

Primary prevention of PPH is extremely important to reduce the incidence of this obstetric complication. ‘Active management’ of the third stage of labour reduces the risk of PPH by 40%. It includes the administration of an oxytocic agent (usually Syntocinon 10 IU) prophylactically at delivery, after the delivery of the anterior shoulder of the baby, as well as early cord clamping (hastens placental separation), and delivery of the placenta with controlled cord traction. Retained placenta is a major cause of PPH, and if retained longer than 30 minutes, a manual removal should be performed. The Brandt-Andrews method (controlled cord traction with suprapubic pressure on the uterus to prevent uterine inversion, after positive signs of placental separation have been witnessed) helps to reduce the time to delivery of the placenta.

Secondary prevention is where a patient has experienced a PPH in a previous delivery. Care should be taken to optimise haemoglobin with haematinics prior to the onset of labour. The other key points are listed in the answers to Q3.

A3

Q1

1 mark

• Urine output to be measured hourly: notify if <30 mL per hour

• Start a strict fluid balance chart

1 mark

• Administer intravenous fluids

– 1 L normal saline at 8/24ly rate (125 mL/hour), followed by

– 1 L normal saline at 8/24ly rate, followed by

– 5% dextrose at 8/24ly rate

1 mark

• DVT (deep venous thrombosis) prophylaxis

– Low molecular weight or sodium heparin

– Graduated compression stockings

– +/− intermittent pneumatic compression

2 marks

• Analgesia

– PCA

– Paracetamol 1 g 6/24ly either PR or IV

1 mark

• Nil by mouth (ice chips for comfort)

1 mark

• Antibiotics – not indicated unless evidence of infection (prophylactic antibiotics given at time of operation)

• Blood tests to be performed the next morning:

– FBE

– Urea, electrolytes, creatinine

– Albumin (may lose large amounts in malignant ascites)

1 mark

Q3

• Chest X-ray

• Abdominal X-ray (supine and erect)

• FBE, urea + electrolytes, creatinine

3 marks

Discussion

This scenario tests the ability of the student to manage a patient having a major abdominal procedure in the immediate post-operative period. The second part of the station requires the student to recognise and manage a common post-operative problem (post-operative bowel ileus).

A4

Q1

Mr and Mrs F have been married for 5 years and Mrs F ceased using the combined oral contraceptive pill 3 years ago in order to become pregnant. She is 37 years old and has never been pregnant in the past.

She has 28–30-day cycles and the periods last 4 days. She has never had a problem with her periods.

• No past history of STDs/PID

• Last Pap smear was 3 years ago

• Mr F is 40 years old and has never fathered any children

• No past history of surgery or injury to testes, or of mumps orchitis

• They are both healthy with no other personal history of note

• They have sex 2–3 times a week

• They have no family history of note

• They are non-smokers and occasionally drink alcohol. She is taking folic acid supplementation at a dose of 1 mg/day

• She is a primary school teacher and he is a secondary school teacher

• They are both very frustrated about their inability to become pregnant

8 marks total (depending on completeness of history)

Discussion

The definition of infertility is one year of unprotected intercourse without conception. Fifteen per cent of couples are infertile (sterile and subfertile); 3 per cent of couples are sterile due to azospermia, absent ovulation or female genital tract obstruction. One in 7 couples are infertile at age 30–34 years, 1 in 5 at age 35–39 years and 1 in 4 at age 40–44 years.

Infertility is a growing problem and may be due to a number of factors: 1) postponement of childbearing; 2) increasing and effective use of contraception; 3) greater accessibility to abortion; 4) rising incidence of sexually transmitted infections (STI), especially in developing countries; and 5) possible environmental toxins. Smokers take longer to become pregnant and are also at greater risk of spontaneous abortion.

In each ovulatory cycle a couple has a 20–25% chance of pregnancy (monthly probability of conception or fecundability). After 3 months of exposure 65% of couples are pregnant, after 6 months 75% are pregnant, after 1 year 85% are pregnant and after 2 years 95% are pregnant. Most infertility investigations are carried out after one year of infertility, except in a woman over the age of 35 years, when investigation should be begun after 6 months of infertility.

Infertility is classified as primary (never pregnant) or secondary (has been pregnant, no matter the outcome).

It is important that a history and examination are performed on the couple. Key points to note from each are their age, the duration of the infertility and whether it is primary or secondary, and if pregnancies have occurred outside the current partnership. A sexual history should be obtained taking note of the frequency of sexual intercourse and whether it is timed to ovulation.

For the woman the history should involve the frequency of the menstrual cycle, its duration and other associated factors such as heavy bleeding or pain. Prior obstetric and gynaecological history, such as the occurrence of an STI, as well as medical and surgical history and family history, are important. There are some medical conditions, such as pulmonary artery hypertension, that preclude pregnancy. The use of medications (prescribed and over-the-counter), as well as the use of cigarettes, alcohol and illicit drugs should be noted. A general and gynaecological examination should be performed, taking note of the size of the uterus, its position, shape and mobility, as well as the size of the ovaries, if able to be palpated. Tenderness on examination should be noted. A Pap smear must be done if due.

For the man the past and current history is important, such as the occurrence of an STI or a mumps infection as an adult. Prior surgical history is also important to note, such as an orchidopexy. The use of medications (prescribed and over-the-counter), as well as the use of cigarettes, alcohol and illicit drugs, should be noted. A general and scrotal examination should be performed, taking note of the size, shape and consistency of the testes, as well as the presence of the vas deferens, varicocoele, hydrocoele or hernia.

The aetiology of infertility is varied and often more than one problem may be present in each couple. The following are possible causes of infertility:

• Cervical and uterine

• Unexplained.

The more severe the diagnosed cause of infertility, the better the prognosis for conception after treatment, provided that the treatment completely corrects the problem. Minor abnormalities alone may not have an impact, but when they occur in combination the probability of pregnancy may be very low. The duration of infertility and the time remaining for conception may be more important than the cause of infertility itself.

Male infertility

Most causes of male infertility are not amenable to treatment. The most common problem is a decrease in sperm production (hypospermatogenesis) as a result of a testicular problem. This may be acquired as a result of mumps infection or it may be congenital as a result of a chromosomal problem such as Klinefelter’s syndrome. Six per cent of men with severe oligospermia (concentration <10 × 10⁶/mL) have a karyotypic abnormality and some of these men may also have a genetic problem with sperm production which involves a deletion of a part of their Y chromosome that is important in sperm production.

Males may also have an obstructive cause for their infertility. This may be acquired due to epididymo-orchitis secondary to an STI or as a result of vasectomy, or it could be congenital, such as due to congenital absence of the vas deferens. In most obstructive causes the male presents with azospermia.

Rarely, hypospermatogenesis may be due to a hypothalamic problem such as congenital Kallman’s syndrome or a pituitary problem such as a prolactinoma. In these cases there is a lack of stimulation of the testis by FSH and LH. These causes are amenable to treatment.

The testes also produce testosterone and some men with severe male infertility may need to consider testosterone replacement therapy once their infertility treatment is completed.

Ovulatory disorders

The most common disorder of ovulation that affects fertility is polycystic ovarian syndrome (PCOS). Women with this disorder have oligo-ovulation and are often hirsute and obese.

Other causes for ovulatory infertility may be due to hypothalamic problems such as weight loss or a pituitary disorder such as prolactinoma. In these cases there is no stimulation of the ovary because of a disorder of production of FSH and LH.

The ovary may not be responsive to stimulation. This is termed premature ovarian failure and is not amenable to infertility therapy.

Tubal factor

Tubal factor infertility is secondary to pelvic inflammatory disease (PID). The increasing incidence of STIs, which cause PID and tubal damage, is responsible for the increasing incidence of infertility, particularly in developing countries. The most common organisms that cause PID are Chlamydia trachomatis and Neisseria gonorrhoea. The problem with both these STIs is that they are often asymptomatic at the time of infection and therefore go untreated; a tubal factor is diagnosed later at the time of infertility investigation when pelvic adhesions and tubal damage are found, such as a hydrosalpinx. Other causes for tubal and pelvic disease are related to the presence of pelvic adhesions due to previous surgery (e.g. ruptured appendix), as well as inflammatory bowel disease (e.g. Crohn’s disease).

Age

There is a definite age-related decline in fertility. In a study of women in a donor insemination program it was shown that there is a progressive decline in the pregnancy rate after the age of 30 years. One-third of women who defer pregnancy until over the age of 35 years will have an infertility problem. For the 40–44-year-old age group the monthly fecundity rate is about 5%, while it is negligible in women 45–49 years old, when only 2–5% will have a viable pregnancy.

Age-related decline in infertility is due to the quantity and quality of oocytes still present, as well as the greater likelihood of the presence of conditions such as endometriosis. There is also a greater likelihood for spontaneous abortion in older women, reaching a rate of almost 50% in a woman older than 40 years. This is mostly due to autosomal trisomies.

Endometriosis

Endometriosis is the presence of ectopic endometrial tissue in the pelvis. With every menstrual cycle this tissue bleeds and is irritating to the peritoneum. It is the reason for the dysmenorrhoea that is experienced by women with this disease. The areas heal by scarring and can therefore cause adhesions and a distortion of the pelvic anatomy. This distortion is the most likely reason for the infertility experienced by women with endometriosis.

Coital problems

These problems may be related to either physical (diabetes, alcohol, medications – e.g. anti-androgens, antihypertensives) and/or psychological causes of impotence in the male. There may also be an inability to ejaculate into the vagina due to hypospadius. Female problems include psychological factors causing vaginismus as well as physical factors related to problems in the vagina such as occur after radiotherapy.

Cervical and uterine factors

The only definite and rare reasons for cervical factor infertility are due to conisation of the cervix by whatever method and cervical amputation (Manchester repair). These procedures may cause cervical stenosis and lack of mucus production. The cervix and cervical mucus are important because they: 1) aid sperm receptivity; 2) protect the sperm from the hostile acidic and phagocytic vaginal environment; 3) supplement energy for sperm metabolism; 4) filter abnormal and nonmotile sperm; and 5) act as a sperm reservoir. Also the cervix is a possible site for sperm capacitation.

Uterine factors include uterine adhesions, which are often acquired as a result of surgery or infection. Uterine leiomyomas and polyps as a cause of infertility remains controversial. In general, these factors are more likely related to abortion rather than infertility.

Unexplained infertility

Couples with idiopathic infertility may have subtle ovulatory, tubal and/or sperm functional problems that are unable to be diagnosed by current technology. Couples with idiopathic infertility have a 35–50% cumulative pregnancy rate after 2 years of follow-up and 60–70% rate after 3 years of follow-up. However, if they are infertile for 4 or more years they have a very poor prognosis. The rate of spontaneous pregnancies in these couples also decreases with age of the female partner.

It is mandatory that both partners be investigated. Investigations are those that will alter the management plan. The basic infertility investigations include: 1) semen analysis and sperm antibody assessment (SA+IBT); 2) tubal assessment; 3) hormonal assessment, including tests of ovarian reserve and ovulation and thyroid function. Rubella and varicella immunity should also be performed and the female immunised if she is not immune. Other hormonal tests will need to be considered if an ovulatory disorder is suspected.

Semen analysis and sperm antibody assessment is based on strict World Health Organization (WHO) criteria. A normal SA is a:

• volume of 2–5 mL

• pH 7.2–7.8

• concentration of greater than 20 × 10⁶/mL

• greater than 50% motility, further defined depending on the type of movement and its speed

• greater than 15% normal forms

• less than 1 x 10⁶/mL WBC.

The viscosity of the semen is noted and liquefaction should take place within 30 min. Fructose content (seminal vesicle) and acid phosphatase (prostate) can also be assessed. The period of abstinence prior to a semen analysis should be 2–3 days and the specimen should be collected by masturbation. If not performed in the office, it should be examined within 1 h of production. If 1 SA is abnormal it should be repeated at least twice, one month apart, for a male factor problem to be diagnosed.

Sperm antibodies should be assessed routinely as 6% of men have these antibodies for no apparent reason. The antibodies can be localised to the head, midpiece or tail and can affect sperm movement or fertilisation by preventing the sperm from recognising the egg. About 50% of men who have had a vasectomy reversal develop sperm antibodies and about 50% of such men father children.

The most comprehensive assessment of the pelvis, tubal normality and patency and endometrial normality is performed with a laparoscopy and hysteroscopy. A hysterosalpingogram (HSG) can also be performed, although it only gives information on tubal patency and normality. It is best considered if a woman has a contraindication or is at high risk of complication at laparoscopic surgery. Both tests for tubal patency may be therapeutic.

All women should be assessed for ovarian reserve. At Monash IVF, an FSH greater than 10 IU/L and an E₂ greater than 200 pmol/mL is considered abnormal and guarded prognosis given to the woman in terms of treatment success. An FSH greater than 20 IU/L is an indication for the use of donor oocytes. A high E₂ (>200 pmol/mL) with a normal FSH may indicate earlier follicular recruitment which will mask an otherwise high FSH and also indicates a poor prognosis. A basal FSH concentration may be a better predictor of fertility outcome than age. Women who smoke have a higher FSH level as do women with one ovary. A mid luteal progesterone concentration (MLP) can also be useful. A serum P concentration less than 5 nmol/mL is diagnostic of anovulation if performed at the correct time. The ideal concentration on day 21 of a 28-day cycle should be greater than 30 nmol/mL. With differing cycle lengths the time that the MLP is assessed will change.

Thyroid assessment, such as a TSH, should be routinely performed in all women with infertility. Hypothyroidism in particular is often silent and can contribute to infertility, particularly by affecting the menstrual cycle. It is easily treated. Hypothyroidism in the mother can cause hypothyroidism in the fetus, which can cause slow brain development.

The treatment of the couple is geared towards the cause for their infertility and the number of factors that are present. At all points they should be involved in treatment decisions. If no cause for the infertility is diagnosed this does not mean that there is no treatment and once again they should be allowed to choose what to do, particularly the no-treatment or conservative option.

If a male factor is diagnosed and is amenable to treatment this should be undertaken. However, most males cannot be treated and their infertility is bypassed with the use of in vitro fertilisation (IVF), most often with microinjection (IVF and ICSI), where each of the female’s eggs that are retrieved are injected with a motile sperm.

Tubal factor infertility is also often bypassed with the use of IVF. Endometriosis-related infertility can be treated surgically to normalise the anatomy, but can also be treated with IVF if severe.

Ovulatory disorders are often treated medically and if they are the only cause present, successful induction of ovulation will often give the couple the same chance of pregnancy as those where the female ovulates regularly.

The use of 0.4 mg supplemental folic acid is important and should be begun at least 3 months before the couple try for a pregnancy. If not started then they should be begun when they present. This dose has been shown to decrease the risk of neural tube defects.

The three most significant prognostic factors for infertile couples are the period of infertility, female age and the type of infertility. With proper evaluation and treatment at least 50% of couples who attend an infertility clinic will become pregnant. When couples become pregnant there is no difference in obstetric outcome than there is for a fertile couple, taking into account their age, parity and the presence of a multiple pregnancy.

Some couples will never become pregnant with or without treatment and they may choose to remain childless or to adopt. In Australia adoption is difficult because there are few babies offered for adoption. In addition, all adoptions in Victoria are open. International adoption is often easier but can be expensive. In general, adoption is a positive alternative for those who want mostly to be parents. Most adoptions are successful and most adoptees are emotionally healthy and consider it to be a positive experience.

The major shift in the emotional

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Tags: Practice OSCEs in Obstetrics & Gynaecology

Jun 15, 2016 | Posted by admin in GYNECOLOGY | Comments Off

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Medical student OSCE answers and discussion

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