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Tuesday 22 September 2015

Is this a case of White Coat Myopia?

A 6-year-old girl was referred to the ophthalmology clinic by the School Health Service of the Health Promotion Board. She had been referred for a re-assessment at the Board after she was identified as myopic in a mass vision test performed at her primary school. The results of her vision test during the mass screening was 6/18 and 6/9, for the right and left eye, respectively. As her right eye vision test result was greater than 6/9, she was then referred to do a re-assessment at the Board. The results of her vision re-assessment were 6/18 correctable to 6/9 and 6/12 correctable to 6/6, for the right and left eye, respectively. The attending optometrist was contemplating on giving her a prescription for glasses or to refer her to the ophthalmology clinic. The point of concern was that the girl’s vision could not be corrected to 6/6 with the appropriate lenses. To err on the side of caution, she was referred to the National University Hospital Medical Centre.

She was born following a normal full-term pregnancy by vacuum-assisted delivery. There were no neonatal problems and her development was normal. She was often described as a very lively child but timid and fearful of doctors, teachers and other seemingly authoritative figures.
Both her parents do not have myopia though her grandmother had amblyopia, commonly known as lazy eye.

At the ophthalmology clinic, though her visual acuity test indicated that one of her eyes has poorer vision than the other, her 3-D vision test was ‘normal’. Her vision test was found to be 6/6 for both her eyes and her dilated eye examination did not reveal any significant findings. She was discharged as having normal vision and does not need any glasses.


The question now is that how was she assessed as having myopia on two earlier occasions? Wouldn’t the prescribed glasses have worsened her vision since it was not needed in the first instance? The ophthalmologist clarified that vision tests for children could sometimes be inaccurate as they rely heavily on the child’s responses and the subjective interpretation of the optometrist. A child that is uncooperative because she/he is shy might end up with a poor test vision result. Upon further discussion with the girl’s mother, it was found the mother was absent on the two earlier ‘failed’ vision assessments and was only present at the last eye-examination session. Could the girl had been so anxious that she could not read aloud the letters flashed before her, only to be calm enough to do so when her mother is present?  Is this a case of anxiety-induced myopia or what I like to call it White Coat Myopia?

Tuesday 15 September 2015

Clearing the haze on PSI

What is PSI? Pollutant Standards Index (PSI) does not differ much from the Air Quality Index (AQI) used by U.S. Environmental Protection Agency (EPA) and in many cities around the world.

Both indices are calculated1,2 based on 24-hour average concentrations of pollutants. The highest index for each pollutant (based on a calculation as depicted below) will be taken as the AQI/PSI.



Hence the PSI is a reported value of the highest pollutant within the past 24 hour.

The NEA further reports 3-hour PSI readings. During periods of smoke haze, as PM2.5 (particulate matter <2.5mm) is the dominant pollutant of concern, the 3-hour PSI is the index calculated based on the PM2.5 concentration levels averaged across 3 hours.

Since most studies on the health effects of PM have used the 24-hour measurements, the health advisory in Singapore takes reference from the 24-hour PSI.

For individuals who wish to make adjustments to their daily activities, one can refer to 3-hour PSI readings or 1-hour PM2.5 concentration levels. The 1-hour PM2.5 concentration levels gives the pollutant levels of each geographical region – North, South, East, West, Central – of Singapore. The following graph shows the corresponding AQI/PSI value of PM2.5 concentration levels. Do note that for PM2.5 concentration levels between 12 and 150 mcg/m3, the PSI value will be lower than the AQI value.





The online calculator to convert PM2.5 concentration levels to AQI is available here.

How important are these numbers? Can we just rely on visibility and smell? In a Straits Times article dated 13 Mar 20143, Dr Erik Velasco, a research scientist who studies air pollution at the Singapore-MIT Alliance for Research and Technology said, “But while the haze might smell bad, its odour cannot be used to judge how harmful it might be”. He added: "The intensity of smell cannot be used to quantify the concentration of pollutants in the air. Both visibility and smell are just qualitative indicators."


Regions for Air Quality Reporting4

Region
Town Centres /Areas
North
Admirality, Kranji, Woodlands, Sembawang, Yishun, Yio Chu Kang, Seletar, Sengkang
South
Holland, Queenstown, Bukit Merah, Telok Blangah, Pasir Panjang, Sentosa, Bukit Timah, Newton, Orchard, City, Marina South
East
Serangoon, Punggol, Hougang, Tampines, Pasir Ris, Loyang, Simei, Kallang, Katong, East Coast, Macpherson, Bedok, Pulau Ubin, Pulau Tekong
West
Lim Chu Kang, Choa Chu Kang, Bukit Panjang, Tuas, Jurong East, Jurong West, Jurong Industrial Estate, Bukit Batok, Hillview, West Coast, Clementi
Central
Thomson, Marymount, Sin Ming, Ang Mo Kio, Bishan, Serangoon Gardens, MacRitchie, Toa Payoh


Wednesday 9 September 2015

Singapore Government Savings Bonds

For the next 5 years, the Singapore Government will be issuing Savings Bonds every month. The monies collected will be used for investments. Unlike Singapore Government Securities (SGS), these Savings Bonds cannot be traded.


Below are some key points on the Singapore Government Savings Bonds:

  1. What do I need to buy Singapore Government Savings Bonds?
  • A bank account and ATM card with UOB/OCBC/DBS/POSB
  • An individual CDP account (individuals must be at least18 years old) linked to the bank

  1. How can I make an application?
  • Via ATM or internet banking for POSB/DBS account holders
  • On 1st work day up to 4th last work day of the month
  • Money will be deducted at point of application, unsuccessful applications will be returned on 2nd last work day into the bank account that was used to make the application
  • Successful applications will be credited into CDP on 1st work day of the issue month
  • Each transaction fee is $2
  • Important dates of each issuance can be viewed on the calendar
  • Minimum investment is $500, and in multiples of $500 up $50,000 for each issue. The maximum amount held across all issues cannot exceed $100,000.

  1. How can I make redemption?
  • Via ATM or internet banking for POSB/DBS account holders
  • On 1st work day up to 4th last work day of the month
  • Principal and accrued interest will be credited into the CDP-linked bank account on the 2nd work day of the following month
  • Each transaction fee is $2
  • Minimum redemption is $500, and in multiples of $500 up to the total amount invested.

  1. Tell me more about the interest payment.
  • Interest rates are stepped-up interests with increasing interest as the bond is held until maturity. Interest rates for each Savings Bond issue is available here
  • Interest payments will be directly credited into the CDP-linked bank account on 1st business day of 6th month and 12th month
  • The interest rates of each Savings Bond issue are based on the average Singapore Government Securities (SGS) yields the month before applications for that issue open

  1. At maturity, the principal and last interest payment will be directly credited into the CDP-linked bank account. There will be no $2 transaction fee.
For any particular issue, if the total amount of applications exceeds the amount of bonds available, one will not get the full amount of bonds applied for. In the worst case scenario, if one is not even allotted the minimum amount $500, the $2 transaction fee is lost. And at 1% interest rate, if one is allotted the minimum $500, the holding period should be at least 1 year in order to break even and start to accumulate interest.

Friday 21 August 2015

Can pickle juice reduce muscle cramps?

I used to be afraid of swimming as I there was once when I witnessed my sister shouting for help from the pool. “Cramp! Cramp!” she yelled as one of her hands were gripping on one leg. Thankfully, she was near the side of the pool and could reach it to lift her head above water. The lifeguard on duty then brought her out of the pool and her leg was straightened, calf stretched, in order to relieve the pain on her leg. What she had experienced is known as exercise-associated muscle cramps (EAMC).

EAMC are painful, sudden, involuntary contractions of skeletal muscle occurring during or after exercise and are recognized by visible bulging or knotting of the whole, or part of, a muscle. The cause of EAMC is still not clear while many scientists hypothesize that it could be due to electrolyte imbalance, dehydration. Without a clear cause, it would be even harder to establish treatment and prevention strategies.

As many as 25% of athletic trainers administer pickle juice (PJ) to treat EAMC1. What is pickle juice? Yes, it is that brackish liquid left over in the jar after you eat all the pickles. And to be specific, it is not even “juice”, it is brine – a salt solution meant to preserve food, but we will still use the term PJ in this article. In one landmark study, Miller KC demonstrated the effectiveness of PJ in reducing muscle cramps2 (more about this study later). The PJ used by Miller in other similar PJ studies3-7 were strained from sliced/whole dill pickles (Vlasic Pickles by Pinnacle Foods Group LLC, Cherry Hill, NJ).


 Photo taken from product website

Now, about the study, Miller and researchers induced muscle cramps on the sole of the foot (flexor hallucis brevis) of hypohydrated male subjects (approximately 3% body weight loss). It was found that ingestion of 1ml/kg of PJ (If you weigh 57kg, ingest 57mLs) reduced cramp duration by 37% when compared to ingestion of water. In this and other Miller PJ studies, the ingestion of PJ did not affect plasma sodium concentration, plasma potassium concentration, plasma osmolality, exercise performance nor thermoregulatory measures.


It is strange that Miller did only one efficacy study on PJ, but it is probably okay to try since ingestion does not affect plasma (blood) electrolyte constituents.

If you'd like to make your own, here's a common recipe:
1 cup of purified water
1 cup of white vinegar/ apple cider vinegar (5% acetic acid)
2 tablespoon of kosher salt
1 tablespoon of pickling spice (optional)

Is this adequate or do you need to add whole/sliced dills?


REFERENCES
  1. Plasma and electrolyte changes in exercising humans after ingestion of multiple boluses of pickle juice. McKenney MA1, Miller KC, Deal JE, Garden-Robinson JA, Rhee YS. J Athl Train. 2015 Feb;50(2):141-6.
  2. Reflex inhibition of electrically induced muscle cramps in hypohydrated humans. Miller KC, Mack GW, Knight KL, Hopkins JT, Draper DO, Fields PJ, Hunter I. Med Sci Sports Exerc. 2010 May;42(5):953-61.
  3. Electrolyte and plasma responses after pickle juice, mustard, and deionized water ingestion in dehydrated humans. Miller KC. J Athl Train. 2014 May-Jun;49(3):360-7.
  4. Pre-exercise ingestion of pickle juice, hypertonic saline, or water and aerobic performance and thermoregulation. Peikert J, Miller KC, Albrecht J, Tucker J, Deal J. J Athl Train. 2014 Mar-Apr;49(2):204-9.
  5. Ad libitum fluid intake and plasma responses after pickle juice, hypertonic saline, or deionized water ingestion. Allen S, Miller KC, Albrecht J, Garden-Robinson J, Blodgett-Salafia E. J Athl Train. 2013 Nov-Dec;48(6):734-40.
  6. Gastric emptying after pickle-juice ingestion in rested, euhydrated humans. Miller KC, Mack GW, Knight KL. J Athl Train. 2010 Nov-Dec;45(6):601-8.
  7. Electrolyte and plasma changes after ingestion of pickle juice, water, and a common carbohydrate-electrolyte solution. Miller KC, Mack G, Knight KL. J Athl Train. 2009 Sep-Oct;44(5):454-61.

Wednesday 29 July 2015

Travel medication checklist

When travelling, I like to bring along medication to relieve symptoms of common illnesses. This is useful for the following reasons:
1)       Medical help may not be available especially when travelling on a long flight or by sea, including geographically remote areas
2)       Medicines may be classified differently in foreign countries such that our usual over-the-counter medicine may require a prescription (a visit to the local doctor) to purchase.
3)       The usual combination drugs or brand names that we are used to may not be always available; and of course lastly
4)       If limited English is used in the foreign country, it would be very hard to get the right medication.

Below is my travel medication checklist:
Adult
Symptom
Medicine
Diarrhea
Charcoal tab
Gastric pain
Antacid
Headache/fever
Paracetamol
Runny nose
Cetirizine


Children
Symptom
Medicine
Diarrhea/loose stool
Lacteofort
Fever
Paracetamol / Ibuprofen
Runny nose
Fedac / Actifed


I would bring along only medicines that I have used before to prevent any ‘surprise’ reactions that may accompany unfamiliar medicines.

Friday 24 July 2015

What makes someone tic?


Excessive blinking is blinking that seems more frequent or forceful than normal, involving one or both eyes.  Excessive blinking can be due to1
  1. Abnormalities to eyelids or front surface of eye (37%)
  2. Ocular tic disorders (23%)
  3. uncorrected refractive errors (need for glasses) (14%)
  4. intermittent exotropia (occasional turning out of the eye, especially when in bright sunlight) (11%)

All of the above except (2) can be easily diagnosed and treated by an ophthalmologist.

What are tics?
Tics are repetitive muscular movements (motor tics) or utterances (vocal tics) that can be transient or persistent, local or widely generalised. About 13% of children have tics disorders and it starts to appear between ages 6-12 years2. By the age of 7 years, approximately 5% of children have a history of such abnormal movement disorders. Tics may be a continuum from mild, simple, suppressible tics to chronic multiple, and complex ones. Complex tics involving both motor and vocal tics may be classified as Tourette syndrome. 90% of childhood ocular tics are transient (lasting less than one year) and resolve spontaneously3. Tics possess three key features4 that can help differentiate them from other movement disorders: (1) they are often preceded by a sensation and an irresistible urge to move known as premonitory urge; (2) they can be wilfully suppressed; and (3) they persist in all stages of sleep.

See video on Tourette Syndrome

So, what really causes tics?
There is no known cause but its onset is said to coincide with a temporarily stressful event in susceptible individuals. Children with tics usually present to a paediatrician with accompanying emotional disturbances. It is also highly hereditary and is thought to be autosomal dominant (the presence of only one gene is required to exhibit this disorder). One study concluded that ocular tics are not related to mothering behaviour. Tics may occur more frequently when a child is tired, stressed or excited.

Are there any treatments for tics5?
Tics can be diagnosed by neurologists and psychiatrists. It is important to note that tics often are not the worst problem and treatment is not always needed. Most treatments are purely symptomatic and that there are no known curative or preventive treatments. Furthermore, symptoms frequently improve or worsen over any period of time, even in untreated individuals. As such, apparent success or failure of any treatment may be coincidental.
  1. Drug therapy : Most commonly Dopamine D2 receptor antagonist therapy
  2. Habit reversal therapy
This therapy involves the application of a competing response whenever the patient notices either a tic or the urge to tic. Central to this is that the competing response must be paired with tic urges or tics, for benefits to be observed. Note that this is very different from simply telling the patient not to tic, or from "trying harder," neither of which is effective over the long run. Initially, heavy effort on the part of the patient may be needed. However, at long-term follow-up at least 50% of treated patients had greater than 75% reduction in overall tic severity, whether based on self-report of home tic counts or on blind review of a videotape filmed in the clinic. The effort expended by patients decreased dramatically as tic frequency declined, usually within the first few weeks of treatment.

My personal experience with tics
I remember having excessive blinking as a child, my mother used to nag at me to stop the blinking. But as I could recall, the blinking was involuntary and I could not control it. As a matter of fact, the constant nagging made things worse as I would try to avoid facing people for fear that they would see me tic. My mother said that it started when I was about 5 or 6 years old. It went away on its own before I turned 7 and I could remember vividly my sister said “You, you stopped blinking already!”. I was overjoyed that it finally went away, something that I had no control over. 


REFERENCES
1.       Ophthalmology. 2001 Sep;108(9):1556-61. Excessive blinking in childhood: a prospective evaluation of 99 children. Coats DK1, Paysse EA, Kim DS.
2.       Pediatrics. 1989 Jun;83(6):967-70. Functional blinking in childhood. Vrabec TR, Levin AV, Nelson LB.
3.       J AAPOS. 2004 Apr;8(2):171-4. Tic disorders in children with frequent eye blinking. Jung HY, Chung SJ, Hwang JM.
4.       Bntish Journal of Ophthalmology 1992; 76: 697-699. Eye movement tics F Shawkat, C M Harris; M Jacobs, D Taylor, E M Brett
5.       Medscape Practice Essentials: Tourette Syndrome and Other Tic Disorders http://emedicine.medscape.com/article/1182258-overview

Thursday 16 July 2015

Fedac (or Actifed) dosage to relieve the common cold


Fedac (or Actifed) is the brand name of a combination product of Triprolidine 1.25mg/5mL and Pseudoephedrine 30mg/5mL. Triprolidine is an antihistamine that helps stop sneezing, runny nose and watery eyes (like blocking a leaky tap!) Pseudoephedrine is the decongestant component that relieves nasal congestion and blocked sinuses (opens a choked tap!). These symptoms can be present either singly or in combination when one catches a cold or flu. I know, it doesn’t make sense to have blocked nose and runny nose at the same time, but it does happen, not at the exact same minute (hour) but they can present at different times of the day. Hence, these two ingredients are commonly prescribed together.
How much to take?
Adults and children over 12 years: 10ml
Children 6 - 12 years: 5ml
Children 2 - 5 years: 2.5ml
Below two years: As recommended by doctor ( My #3 who was 1.5 yrs old and 10kg was prescribed 1.5mL)
Doses to be taken 8 hourly.
As the weight for children 2 to 5 years old is wide, I prefer to use the dosage by weight based on Pseudoephedrine.
Weight (kg)
Volume Fedac (mL)
8
1.3
9
1.4
10
1.5
11
1.7
12
1.8
13
2.0
14
2.1
15
2.3
16
2.4
17
2.6
18
2.8
19
2.9
20
3.0
21
3.2
22
3.4
23
3.5
24
3.7


It is common to experience drowsiness after taking Fedac, hence what I usually do is to give it to my child only at night if the symptoms are not severe. This medicine is just a symptom reliever after all and the body will have to fight the cold/flu on its own.

Monday 19 January 2015

Reducing suicide risks by taking a EPA and DHA



My classmate from university, C passed away on 16 January at age 39. He had jumped to his death, apparently after battling depression for the past two years. His father witnessed the incident.

I am very saddened by his choice – an irreversible choice – when one ultimately takes one’s own life. Perhaps it might be a good choice for him – if he had been miserable all these while. Perhaps, it might be a good choice for those around him – if they had been helpless and had seen him struggle through each day.

One thing’s for sure, I will never see or hear from C again. I dedicate this to him:

Last night as I lay on my bed,
I wondered what had made you done so;
Last night as I lay on my bed,
I can’t bear to see you go…………….

As a pharmacist, he probably would have known and could gain access to antidepressants if he ever needed them. I don’t know if he took any medication. In 2003, a well publicized US FDA warning on the use of antidepressants – that is it increases the risks of suicidal behaviours – might have led to a reduced use of antidepressants for the past 10 years1. The same report indicated a simultaneous significant rise in suicide attempts. Indeed the search for a ‘cure’ to prevent suicide by the usual pharmacological experimental models would be very difficult2
-          Suicide death and suicide attempt are rare outcomes, very large sample sizes and long observation periods are required to detect effects.
-          It would not be ethical to have a placebo arm in such high-risk studies.

Of interest is that polyunsaturated fatty acids may play a role in reducing suicidal behavior3. In recent years, substantial evidence has linked a dietary deficiency in essential long-chain omega-3 (LCn-3) fatty acids, eicosapenaenoic acid (EPA) and docosahexaenoic acid (DHA), to the occurrences of major depressive disorder, bipolar disorder, schizophrenia, attention deficit hyperactivity disorder (ADHD), and anxiety disorders. The evidence suggests that EPA+DHA doses in the range of 1–4 g/d are potentially efficacous and are safe and well-tolerated in pediatric, adolescent, and adult psychiatric patients. In particular, the EPA+DHA in a 2:1 EPA to DHA ratio are efficacious for the treatment of mood symptoms and a larger ratio of EPA to DHA may be more efficacious for treating depressive symptoms as well as ADHD symptoms. To minimize the gastrointestinal adverse events (nausea, diarrhea, gastroesophageal reflux, eructation) associated with LCn-3 fatty acids, patients should be instructed to take their pills with meals.

Now, is it that simple? Could eating more fish be able to safe C? Could he had led happier lives by popping omega-3 fatty acid supplements?


  1. Lu CY et al. Changes in antidepressant use by young people and suicidal behavior after FDA warnings and media coverage: quasi-experimental study. BMJ. 2014 Jun 18;348:g3596.
  2. Mann JJ, Currier D. Medication in Suicide Prevention. Insights from Neurobiology of Suicidal Behavior.The Neurobiological Basis of Suicide. Boca Raton (FL): CRC Press; 2012. Chapter 21.
  3. McNamara RK, Strawn JR. Role of Long-Chain Omega-3 Fatty Acids in Psychiatric Practice. PharmaNutrition. 2013 Apr;1(2):41-49.