Immune Thrombocytopenia

Immune

1

"You know, we might as well be vampires", your colleague says, while munching on a potato chip. The two of you are relaxing in the doctors' lounge, watching the latest supernatural soap opera (it's about a chimera), before the start of yet another shift. "Why do you say that?", you ask lazily, while leaning over to grab another chip. "Well, think about it. We have access to all the blood we could want, we look pale and sickly from eating all that cafeteria food, and I can't remember the last time I saw daylight." "You know, you actually might have a point there", you say. "Although we'd probably be dead by now, if we were vampires. These chips are garlic flavored" You both laugh out loud and fail to notice the trainee nurse poking her head in ....


2

"Doctor, there is a patient waiting to see you." "Sure. I'll be there", you manage to say amidst the laughter. Not satisfied with your answer, she lingers on, and asks "How long should I tell them you'll be?" "Exactly 123 seconds!", you reply to the nurse, whose irritated expression shows that she didn't get the joke. Sighing, you get up and leave the lounge. In the background, the chimera gobbles up an unsuspecting mermaid ...


3

Paula Lopez awaits you in the clinic, along with her mother. She is 21 years old, and in the 28th week of gestation of her first pregnancy. Paula has experienced several episodes of mild, painless vaginal bleeding over the past two days, although she is not bleeding right now. There were no associated cramps or contractions. A few hours ago, she experienced a nosebleed, which stopped after she pinched her nose, and applied an ice-pack. However, her mother was highly alarmed, and rushed her over to the family doctor, who recommended that they see you as soon as possible.


4

At this point, her mother, Mrs. Lopez, jumps in and states that she has also noticed purplish bruise like spots on Paula's ankles as well as her shins.


5

Perusal of Paula's medical records reveals no untoward findings. You also notice that she has an appointment scheduled with her obstetrician (who works in the same hospital) tomorrow.


6

On examination, Paula has a pulse of 88 bpm, blood pressure of 110/82 mmHg and a respiratory rate of 22 cycles/min. She is afebrile and anicteric. No lymph nodes are palpable. You also note the presence of petechiae over both ankles. Examination of the abdomen reveals a fundal height compatible with the gestational age. There are no areas of tenderness. The pelvic examination reveals no abnormalities. There is no active vaginal bleeding. You decide to order several basic investigations. The results are as follows: WBC: 10,800/mm3 (4,000-10,000) N: 64% L: 30% Hb: 11.9 g/dl (10.5-17.5) Hct 32.4% Platelets: 24,000/mm3 (150,000-400,000) INR: 1.02 (0.9-1.1) PT: 11.8 sec (10-14) APTT: 38 sec (36-42) Blood Group: A negative. Urinalysis: no red blood cells, pus cells, or cell casts.


8

A highly panicked Mrs. Lopez drags Paula out of your office almost immediately after you finish speaking. Some time later, you receive a call from the head of the emergency department. "Why did you send a perfectly stable patient over here? Have you absolutely no idea of what constitutes an emergency?", she angrily asks. "But, I ....", you blurt out, but she does not allow you to get a word in. "If you think that she needs admission, please make the appropriate arrangements. I'll be sending her back to you now", she says and slams the phone down. Chargined, you arrange to have Paula admitted, and also inform her Obstetrician of the sudden change in plan ...


9

You start to tell Paula that she should take this up with her Obstetrician tomorrow ... ... and quickly shut your mouth, when you note your assistant urgently beckoning at you. She points out the extremely low platelet count (24,000/mm3), and says "Doctor, I really don't think we should send her home. Isn't this a significant thrombocytopenia?" You realise that she is right, and proceed to admit Paula and seek an opinion from her obstetrician.


10

In the ward, the Obstetrician examines Paula, and reports that the symphysiofundal height is compatible with 28 weeks, with a vertex presentation, and that the cervical os is closed. A cardiotocogram shows a fetal heart rate of 160 bpm, with normal variance. An ultrasound scan confirms the obstetric findings, and additionally reveals the liver and spleen to be normal. Subsequently, the obstetrician assures you that the fetus is healthy, and agrees that Paula should receive in-ward treatment.


11

You proceed to request several further investigations, including a peripheral smear, liver and renal function tests, assays for ANA, lupus anticoagulant, and dsDNA, and screening tests for HIV, and Hepatitis B and C. By the time of your next ward round, Paula's test results are in. With some trepidation, you also notice the presence of a new group of medical students .....


12

Paula's peripheral smear confirms the presence of isolated thrombocytopenia, with normal platelet, erythrocyte and leukocyte morphology. There are no features which might suggest pseudothrombocytopenia or an inherited platelet disorder. Her liver and renal function tests are also within normal parameters, while the ANA, lupus anticoagulant and ds-DNA assays and screening tests for HIV, Hepatitis B, and Hepatitis C are also negative.


13

Almost as soon as you are done reading, an overly enthusiastic student in the group quips in. "Does this patient have ITP?", she asks. "Things certainly point that way", you reply. "But shouldn't we perform a bone marrow biopsy to confirm the diagnosis before proceeding?", she counters.


15

As you open your mouth to answer, a student lurking in the back clips in sarcastically. "Yeah, right. Let's go ahead and perform an invasive and totally unnecessary investigation, just because you think it's essential" You pause for a moment, and reply "He is correct. You should all go now and research the indications for a bone marrow biopsy in patients with ITP" Phew. That should get them off your back for a while!


16

"A bone marrow biopsy is not necessary for diagnosis", you remark, while several students in the back snicker at the questioner. "Go ahead and read about the indications for bone marrow biopsy in a patient with ITP. I'll be expecting everyone to know the topic in and out the next time I see you!" Phew. That should keep them off your hair for a while, you think.


17

Now that you have arrived at a working diagnosis of Immune Thrombocytopenic Purpura (ITP), you need to decide on Paula's management.


19

You decide to start Paula on an infusion of intravenous immunoglobulin .... ... and quickly countermand the order as you realize that there is no active bleeding, and that you do not need to correct her platelet count in a hurry. You recall the last lecture the director gave you about "using expensive treatments, when more cost-effective options are clearly available", and shudder.


20

As the words "Anti-D immunoglobulin might work ..." exit your mouth, your assistant, the nursing staff and the students all look at you, flabbergasted. "... if she were not Rh negative.", you quickly add. "Thus, we should start her on corticosteroids instead", you continue, to which statement everyone sagely agrees.


21

You decide to start Paula on a course of corticosteroids ....


22

She responds well, and her platelet counts rise over the next few days.


23

Ten days later, the platelet count has risen to 100,000/mm3, while her corticosteroid dose has been tapered over time. Paula has not experienced any bleeding manifestations since the start of therapy. You decide that she is ready to be discharged, and ask your assistant to schedule regular follow-up visits.


24

Subsequently, you meet up with Paula and her Obstetrician, and discuss the mode and timing of delivery. Paula remarks that she would prefer to have a vaginal birth. The obstetrician then suggests waiting until the 38th week of gestation, and on inducing labor if spontaneous delivery has not occurred by then. Paula arrives for her follow up visits on a regular basis. Both the mother and fetus remain healthy. During her visit at the 37th week of gestation, Paula's platelet count is found to be 90,000/mm3. You reassure her that this is sufficient for both vaginal and Cesarean delivery, and that no interventions are indicated.


25

Just a few days later, you are paged by the emergency room. Rushing over, you see an uncomfortable Paula, who is holding on to her abdomen. She complains of abdominal pain and contractions since waking up today. The Obstetrician arrives soon afterwards and starts examining her. You also realize that it is just one day before her scheduled visit.


26

The Obstetrician states that the cervix is not ripe, and that the cardiotocogram and fetal doppler are suggestive of fetal distress. He is of the opinion that a Cesarean section should be performed as soon as possible, and asks you for your opinion.


27

An urgent complete blood count reveals a platelet count of 82,000/mm3. You mind races as you contemplate what hematological interventions Paula might need right now.


29

The obstetrician interrupts you and points out that neither a transfusion nor IVIG are indicated at her current platelet levels. Chargrined, you keep your mouth firmly shut as he instructs the nursing staff to prepare Paula for the theatre.


30

Both of you agree that Paula does not need any immediate treatments for her thrombocytopenia, and that the cesarean section can go ahead.


31

Just as you think that your troubles are over, the medical student who always asks annoying questions jumps out of the group. "Isn't the neonate at risk of developing thrombocytopenia due to maternal antibodies? Shouldn't we test him for thrombocytopenia via scalp sampling?"


33

As you start to answer in the affirmative, you suddenly remember that current guidelines recommend against fetal scalp sampling ....


34

"Percutaneous umbilical blood sampling is an alternative for fetal scalp sampling in such patients..", you say, and abruptly stop when the obstetrician gives you a sharp look. Your face reddens as you suddenly recall that the risks of the procedure clearly outweigh the likely benefits ....


35

You proceed to give a lengthy discourse on why fetal blood sampling (regardless of technique) is best avoided in these patients. To your relief, your lecture seems to be so comprehensive, that no questions follow ...


36

Subsequently, the obstetrician performs a Cesarean section. A neonatologist attends the procedure. Following delivery, a sample of cord blood is obtained and sent for analysis. No sooner are the test results available, that the neonatologist is on the phone, requesting an opinion on the further management of the baby.


37

The baby's platelet count is 56,000/mm3. A thorough examination excludes petechiae and purpura. There are no signs of active bleeding and vitals are stable, with a heart rate of 118 bpm, respiratory rate of 40 cycles/min, no cyanosis, and normal reflexes.


39

The neonatologist shakes his head in disagreement, and then takes great pleasure in explaining how one should manage a neonate born to a mother with ITP. Embarrassed, you agree with his recommendation to keep Paula's baby under observation for now, with close monitoring of platelet counts until he is 5 days old.


40

Smiling, the neonatologist agrees with your recommendation to keep Paula's baby under observation, and to monitor the platelet counts until the fifth day of life has been passed.


41

"Doctor! Excuse me, doctor!!", you turn around and see the class "gunner" jabbing her hand up in the air, ready with another question. "Will this person ever leave me alone!", you mutter to yourself, and voice out a feeble "Yes?" "Isn't this patient at a high risk of developing venous thromboembolism? Shouldn't we be starting her on postpartum thromboprophylaxis?", she asks.


43

Barely hiding your annoyance, you remind the student that ITP increases the risk of bleeding, and that thus, Paula does not require thromboprophylaxis in her postpartum period. The student looks crestfallen, and does not bother you any more ...


44

Several days later, Paula and her baby have platelet counts of 140,000/mm3 and 280,000/mm3 respectively. Both look healthy and happy. Paula tells you that baby Patrick feeds well. She is overjoyed when you inform her that she can be discharged now ...


45

The following night, you receive an emergency page from the hospital. Upon going there, you find out that Paula has suffered a venous thromboembolism. It only takes an instant for you to realize that this was your fault, and that you should have started her on thromboprophylaxis. The gunner was right after all!


46

You tell the student that she is correct (for once), and that you will be starting Paula on thromboprophylaxis.


47

Several days later, Paula and her baby have platelet counts of 140,000/mm3 and 280,000/mm3 respectively. Both look healthy and happy. Paula tells you that baby Patrick feeds well. She is overjoyed when you inform her that she can be discharged now ... However, before leaving for home, Paula has an important question for you. "Doctor, I did a lot of reading online while I was on bed last week, and I understand that this will most likely resolve over time. But if it persists, how badly will it affect my next pregnancy?"


49

Paula looks at you skeptically. "Are you sure doctor? But the literature I read online said that most recent studies suggest that the severity would be less. Of course I may be wrong…" "Yes, yes", you quickly blurt out. "I was about to get there. The newest evidence does indeed point that way…" Fortunately, you manage to hide your embarrassment well.


50

You explain that according to recent studies, even if she were to develop chronic ITP, the effects on any future pregnancies would very likely be less. Paula nods her head, while listening intently. She tells you that she found similar information online, but did not understand it clearly.


51

Soon afterwards, Paula and her baby are ready to go back home. She can't stop thanking you for "saving my life and my baby too!" Feeling a little pleased with yourself, you head down to the cafeteria to grab a snack. You meet your colleague there, and tell him about your successful treatment of Paula. However, soon afterwards, both of you completely forget ITP and patients, and find yourselves in a heated discussion about the latest episode of your favorite supernatural series.