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Tuesday, January 31, 2012

Sepsis

1. What is the difference between sepsis, septicaemia and septic shock?
2. What are the criteria to diagnose sepsis?
3. What is early direct goal therapy? (EDGT)

1. Systemic Inflammatory Response Syndrome (SIRS)
  • Sepsis: SIRS + infection
  • Severe sepsis: Sepsis + organ hypoperfusion e.g. hypoxaemia, oliguria, lactic acidosis, altered mental function
  • Septic shock: Severe sepsis + hypotension (SBP < 90mmHg) despite adequate fluid resuscitation, or need vasopressor/inotropes to maintain BP
  • Septicaemia: Presence of multiplying bacteria in circulation

2. Diagnosis: SIRS need 2 or more of the below criteria:
  • HR >90 bpm
  • T° >38°C or <36°C
  • RR > 20 breaths/min, or PaCO2 <32mmHg (4.3kPa)
  • WBCC > 12 or <4 x 109/L, or >10% immature band forms
Since sepsis = SIRS + infection, we need 2 or more of the above criteria + culture and sensitivity (C+S) result.
  • C+S taken before antibiotic treatment
  • > 2 blood C+S taken (each 10ml)
  • C+S from percutaneous and vascular device in place

3. Early Goal-Directed Therapy (EGDT) is a more specific form of therapy used for the treatment of severe sepsis and septic shock. This approach involves adjustments of cardiac preload, afterload, and contractility to balance oxygen delivery with an increased oxygen demand before surgery. We need to identify hypotension / serum lactate > 4 mmol/l, if either of them present, administer crystalloid.

Initial goal of resuscitation in < 6hr:
  • CVP = 8-12 mmHg (12-15 mmHg if on mechanical ventilation)
  • MAP > 65 mmHg
  • Urine output > 0.5 ml/kg/hr
  • ScvO> 70%
CVP = central venous pressure
MAP = mean arterial pressure
ScvO= central venous oxygen saturation 


MVA

If a patient who has met MVA (motor-vehicle accident) is brought to you, what is the first thing you would do? 


A preliminary survey can be done following ABCDEF.

A: Airway
Protect cervical spine f injure.
Access airway patency, check for any obstruction.
Establish airway if there is obstruction.

B: Breathing
Check RR, bilateral chest movement, precuss and auscultate.
Consider O2, intubation, or manage according to causes, eg. tension pnuemothorax.

C: Circulation
Check PR, BP, and CRT.
If no cardiac output, do CPR.
If shock, use plasma expander or inotropes.

D: Disability
Access level of consciousness by using Glasgow Coma Scale (GCS) or AVPU score.
  • A = Alert
  • V = responds to Vocal stimuli
  • P = responds to Pain
  • U = Unresponsive
Check pupils: size, equality, light reaction.

E: Exposure
Undress patient, but cover to avoid hypothermia.

F: Find
Check for all possible trauma site


How do you apply cervical collar? 

To apply the cervical collar,
  1. The assistant need to realign the cervical spine by manual stabilisation.
  2. The doctor need to measure the length from the horizontal plane that goes through the chin, to the horizontal plane that goes through the shoulder or the clavicle. This is needed to adjust the size or the cervical collar.
  3. If necessary cut off any cloth that inhibit the application of the cervical collar, e.g. the hood of a jacket.
  4. Slip the posterior piece of the cervical collar behind the neck.
  5. Apply the anterior / front piece of the cervical collar over the neck.
  6. Check whether the cervical collar fits well to the jaw or whether it is too tight.

--- UPDATE ---

I want to emphasize that if an unconscious patient with MVA comes to you, a cervical collar must be applied because you are not sure whether this patient has cervical fracture or not until it is ruled out. 

Monday, January 30, 2012

Bygone Grace & Future Grace

 
 The past is valuable......

......but it can never hinder the future.

I remember I saw this cartoon or joke in a book entitled "Dare2Fail". The author tries to emphasize that even thought the past is memorable and valuable, but we should always look into the future and move on. And it is also from this small cartoon I wrote this line in my second post,

回忆是美好的,但回忆却是个叫我回去的诱饵。
人应放下回忆,张向未来,因为新天新地即将到来。

I retold this to someone, and he replies, "It is very true, but we mustn't forget that the antique car is the foundation of the future modern car." Indeed it is very true, the past is the foundation of the future. 昨天的我造就今天的我。

So in the very same way, this is how the grace of God works. Someone wrote this, "Out of love and gratitude for all God has done for him, a christian does good work to please and glorify God, but he does not trust in his own works for salvation." What is person wrote is quite true, as creations of God we want and we should glorify God, and we trust not in ourselves, but we trust in the power of God.

Before we continue, don't get me wrong. Yes, gratitude is a virtue, and if a christian doesn't have gratitude, I think we can hardly call him 'christian'. But we don't do good work out of gratitude for what God as done for us. If we think in such a way, it sounds like we are debtors and we try to pay of the debt that we owe God by doing good work, and this will make the salvation from God a work-based salvation. No, it doesn't work that way, because Christ has pay the price or the wage of our sins, we shouldn't and we can't pay off our debt that we owes by doing good work.

So since our sins are paid off by Christ's work on the cross, are we off the hook and can do whatever we want, even sinning? "What shall we say, then? Shall we go on sinning so that grace may increase? By no means! We died to sin; how can we live in it any longer?" (Romans 6:1-2).

John Piper describes the christians' faith very well:  
Faith is God's forgiveness does not merely mean a persuasion that I am off the hook. Saving faith cherishes being forgiven by God, and from there rises to cherishing the God who forgives - and all that He is for us in Jesus.

If gratitude of the past is not the answer, then what is the driving force that push us to move on? What is the thing that drives us do good work? What is the provision that God provides for us to continue to live a purified life, to be sanctified?

We can answer this question by asking another question, How the people in Old Testament were saved, since Jesus Christ haven't come and die for them? By obeying the Laws? Obviously no, because All who rely on observing the law are under a curse, for it is written: "Cursed is everyone who does not continue to do everything written in the Book of the Law." (Galatians 3:10) 

The answer is the same for those people in New Testament, by faith in Jesus Christ. All these people were still living by faith when they died. They did not receive the things promised; they only saw them and welcomed them from a distance. And they admitted that they were aliens and strangers on earth. People who say such things show that they are looking for a country of their own. If they had been thinking of the country they had left, they would have had opportunity to return. Instead, they were longing for a better country - a heavenly one. Therefore God is not ashamed to be called their God, for he has prepared a city for them. (Hebrews 11:13-16)

But the difference is that they, as believers in Old Testament, they are justified by looking forward into the future, and put their faith in the grace that God will provide in the future, which is Jesus Christ, and they continue to live on by banking on the future grace that God promised.

We, as believers in the New Testament, on the other side of the cross, also justified by looking backward and putting our faith in Jesus Christ, but still we continue to live on by banking on the future grace that God promised. This is the answer, this is the driving force, that is to live by faith in future grace.

Westminster Confession of Faith 1674 says:
Faith, thus receiving and resting on Christ and his righteousness, is the alone instrument of justification; yet it is not alone in the person justified, but ever accompanied with all the saving graces, and is no dead faith, but worketh by love.

Living by faith in future grace doesn't nullify the bygone grace, because it is this bygone grace that gives us this faith to believe, so that we can be justified. This faith continue to work, so that we can produce fruits, that testify this faith. The reason we can continue to press on and live on as christians because of the future grace that God has promised.  
Note: when I say 'bygone grace' and 'future grace' I am not trying to say that they are two different grace. The same grace that justify us, is the same grace that sanctify us, so maybe I can say that the bygone grace, will continue to work in our life, as future grace.

Just like the analogy, we continue to move on not by driving the antique car, but by inventing new car to drive. In a similar (but not exactly the same) way, we continue to live, not just by gratitude to the bygone grace that God pour out for us on the cross in the past, but by continue to put our faith in the grace and promises of God in the future.

However, I repeat again, living by faith in future grace doesn't nullify the bygone grace. Remember the antique car is the foundation of the modern car. So in a similar way, the bygone grace that God pour out for us on the cross in the past, is the foundation of the future grace that we put our faith in.

He who did not spare his own Son, but gave him up for us all - how will he not also, along with him, graciously give us all things? (Romans 8:32)

It is because of what God done in the past, it is because we know that God has fulfilled His promise in the past, by sending His one and only Son, to die for our sins, it is because of this bygone grace, we know and we can trust that this same God, will fulfill His promise for us in the future, we know and we can continue to live by faith in His future grace.

P/S: For further reading, please refer Future Grace by John Piper.

____________________

Let us fix our eyes on Jesus, the author and perfecter of our faith,
who for the joy set before him endured the cross, scorning its shame,
and sat down at the right hand of the throne of God.
Hebrews 12:2

Thursday, January 19, 2012

LVH, LAD, GCS, RSI

1. How do you diagnose LVH and LAD from ECG?
2. A patient came to you with GCS 7/15(E2V2M3). What is your action? Define GCS.
3. What is RSI? List out the sequence. 

1. Left Ventricle Hypertrophy (LVH)

Romhilt-Estes point score system ("diagnostic" >5 points; "probable" 4 points):
In my opinion it is a rather complex diagnostic criteria.
  1. ECG Criteria Points Voltage Criteria (any of):
    • R or S in limb leads ≥ 20 mm
    • S in V1 or V2 ≥ 30 mm
    • R in V5 or V6 ≥ 30 mm
  2. ST-T Abnormalities: ST-T vector opposite to QRS without digitalis
    ST-T vector opposite to QRS with digitalis
  3. Negative terminal P mode in V1 1 mm in depth and 0.04 sec in duration (indicates left atrial enlargement) 3
  4. Left axis deviation (QRS of -30° or more) 2
  5. QRS duration ≥0.09 sec 1
  6. Delayed intrinsicoid deflection in V5 or V6 (>0.05 sec) 1
  7. Other voltage-based criteria for LVH include:
    • Lead I: R wave > 14 mm
    • Lead aVR: S wave > 15 mm
    • Lead aVL: R wave > 12 mm
    • Lead aVF: R wave > 21 mm
    • Lead V5: R wave > 26 mm
    • Lead V6: R wave > 20 mm
Criteria of LVH on ECG given by my therapy teacher:
  • Left axis deviation (LAD)
  • RV5 taller than RV4
  • RV5/V6 + SV1 > 35 cm (Sokolow-Lyon index)
  • RI + SIII > 25 cm
  • (RI - SI) + (SIII - RIII) > 17 cm (Levis index)
  • RaVL > 11 cm
  • ST depression in left leads (I, aVL, V5, V6)
  • T inversion in left leads (I, aVL, V5, V6)
The most important is the Sokolow-Lyon index, cause it has high specificity, but low sensitivity, e.g. in obese patient the voltage of the ECG waves might be dampen down.
So we should also look for left ventricle strain pattern.
  • Left leads (I, aVL, V5, V6) :T-wave inversion + ST-depression
  • Right leads (III, aVF, V1, V2) : ST-elevation
NB! T-wave inversion can be sign of ischemic damage to the myocardium, but the pattern is different.
  • In LV strain pattern, gradual down-slope of the T-wave + sudden up-slope of the T-wave.
  • In LV ischemia, symmetrical downslope + up-slope of the T-wave. 
  • Compare with the ECG of the ischemia below.


But it is not absolute, and cardiac enzyme e.g. troponin should always be checked to rule out ischemia.

Left Axis Deviation (LAD)
  • RI > RII > RIII.
  • Upward deflection of QRS-complex in I.
    downward deflection of QRS-complex in III.
2. GSC is Glasgow Coma Scale.
  1. Secure ABC of life support.
  2. O2, IV access. Consider intubation since GCS < 8.
  3. Check vital signs: BP, PR, RR, temperature.
  4. Check for any external trauma especially cervical spine trauma.
  5. Check for any sign of increased ICP (ophthalmoscopy).
    Check for meningism. (NB! Don't move neck if cervical spine trauma)
  6. Investigation: FBC, BUSE, ESR, CRP, LFT, Creatinine, ABG, DXT, toxicology screening.
    CXR, ECG, neuroimaging (CT/MRI), LP (if meningism + no increased ICP)
Management will depend on the cause. 

3. RSI is Rapid Sequence Intubation / Induction
I am not quite sure about this procedure especially the medication and dosage, but I'll try answer with what I read on the Internet. RSI refers to the pharmacologically induced sedation and neuromuscular paralysis prior to intubation of the trachea. RSI is generally used in an emergency setting.
  1. Administer 100% oxygen via a nonrebreather mask for 3 minutes for nitrogen washout.
  2. Administer a rapidly-acting induction agent IV to produce loss of consciousness.
  3. Administer a neuromuscular blocking agent IV immediately after the induction agent.
  4. Rapid placement of an endotracheal tube (ETT) between the vocal cords, while the cords are being visualized with the aid of a laryngoscope. 
One important difference between RSI and routine tracheal intubation is that the practitioner does not manually assist the ventilation of the lungs after the onset of general anesthesia and cessation of breathing, until the trachea has been intubated and the cuff has been inflated. 

Another key feature of RSI is the application of manual pressure to the cricoid cartilage, often referred to as the "Sellick maneuver", prior to instrumentation of the airway and intubation of the trachea to prevent regurgitation of gastric contents. However this technique may impede laryngeal view. 

Do share with us more regarding this topic =).

--- UPDATE ---
Answer.

1. LVH: left ventricular hypertrophy. One of the easiest and fastest way is the see V1 and V6. The sum of big box (with 5 small boxes) of R wave in V6 and S wave in V1 must exceed 7 in LVH.

2. GCS: Glascow coma scale. Total number is 15/15(E4V5M6).
E: Eye
  • 4= eyes open spontaneously
  • 3= eyes open in response to call
  • 2= eyes open in response to pain stimuli
  • 1= no eye opening
V: Verbal
  • 5= oriented
  • 4= confused
  • 3= inappropriate words
  • 2= incomprehensible words
  • 1= no voice
M: Motor
  • 6= obey commands
  • 5= localizes to pain
  • 4= withdraw to pain
  • 3= abnormal flexion to pain stimuli
  • 2= abnormal extension to pain stimuli
  • 1= no movement
When the patient comes to us with GCS< 8, theoretically intubation is needed to maintain the airway and also for cerebral protection in case of traumatic brain injury. But first, we must assess the vital sign first. 
Intubation is not needed in case of temporary hypoglycemia. A patient with hypoglycemic attack can have poor GCS. A patient with recurrent massive stroke does not need intubation if GCS is always low all the while. What I want to conclude is that a poor GCS does not necessarily need intubation unless it is indicated and vice versa.


3. RSI: rapid sequence intubation.
It must be done in sequence. (with several "P"s)
1. Preperation
  • We must firstly prepare the patient with good position and instruments for intubation. Things to prepare: medications, ambu bag, bag-valve-mask, yankeuer, suction tube, laryngoscope, endotracheal tube (ETT) with appropriate size, K-Y jelly (lubricant gel), oral airway.
  • RSI must be done with helps. A team must be formed of a leader and few assistants. A assistant must be selected mainly only to perform cricoid pressure.
  • Vital sign monitoring must be ready - you need to observe BP, PR, SPO2, heart beat rhythm during RSI. 
2. Pre-oxygenation
  • Bagging can be done with ambu bag and bag-valve-mask. 
  • Bagging is not necessarily if there is still spontaneous breathing and we only apply the ambu bag on the mouth without bagging. 
  • SPO2 must be maintained at least 99%.

3. Pre-medication
  • There are few sedative medications that are mentioned in literature. I only mention common medication. 
  • Here, we use Midazolam (0.1-0.3mg/kg/dose). 
  • Atropine can be added if there is bradyarrhythmia.
4. Paralysis
  • There are mainly 2 types of paralysing medication we use to paralyse the airway for easy intubation. There are Succhynilcholine and Rocuronium. 
  • We often use S-choline (1-1.5mg/kg/dose). This medication often would cause muscle fasciculation and it is the main sign that we can see after introduction. The fasciculation will trasmit from head till toe and once it reaches the toe, it is time for intubation. Of cause, each drug has its own side effect and neither the patient can escape from this drug. S-choline can cause raised intracranial pressure, bradycardia and hyperkalemia. Please mind that we must avoid this drug for patient with bradycardia, traumatic brain injury, brain tumor, ESRF (end stage renal failure) and so on.
  • In view of S-choline possible adverse effect, Rocuronium would be the substitute. Its usual dosage is 1-1.2mg/kg/dose. After 1 minute of introduction, we are ready to intubate. Of course, due to its prolonged paralysing effect, it is not the first line drug unless it is indicated.
5. Protection
  • Once we introduce sedation and followed by paralysing agent, our assistant needs to perform cricoid pressure. Remember that we can only release the cricoid pressure after successful intubation.
  • Please find out what is cricoid pressure and how to do it.
6. Positioning
  • We need to position the head and the mouth for intubation. 
  • Please find out how you would like to place the head in order to visualize the vocal cord.
7. Placement of tube
  • Please remember that we always use our left hand to hold the laryngoscope. The blade should face towards the patient. Use our dominant hand to open the patient's mouth. With correct position and cricoid pressure, this step would be possible. 
  • The usual size of ETT is 7-7.5mm for adult. ETT with size 8mm is sometimes needed for huge adult patient. ETT is often anchored at 21-22cm at mouth angle. 
  • If ETT is inserted too deep, we can create pneumothorax. 
  • If ETT is inserted too shallow, it can be dislodged or the patient can have insufficient oxygen supply. 
  • After intubation, ETT must be secured. By auscultating the lungs and epigastric region, we can hear the lung breathing sound if the ETT is placed into the airway; otherwise, we can hear sound at epigastric region if the ETT is placed into the esophagus. Esophageal intubation can cause gut perforation and ETT must be taken out and repeated intubation is needed.
8. Post-intubation management
ICU admission must be arranged. CXR must be done. Gauze must be applied over the eyes to avoid eye dryness after intubation. After intubation, 3 things we will see.
  • SPO2: SPO2 will remain 100% after intubation. If SPO2 drops, then there is either something not right with the placement of ETT or other causes, e.g pneumothorax.
  • Chest expansion with out-in going vapor in ETT: Chest will depress with each out-going vapor from ETT.
  • CXR: CXR must be done after intubation to ensure the ETT is in situ.

Doctors must know how to intubate and to perform RSI. It is compulsory!
 

Wednesday, January 18, 2012

AF, CVA, Orange urine

1. What are the common causes of AF(artrial fibrillation)?
2. What you want to rule out in ECG for patient with CVA(cardiovascular accident= stroke)?
3. A patient with PTB came to you and complaint of passing out urine in orange color after taking anti-TB for 3 days. What would you do? 

1. Common causes of Artrial Fibrillation (AF)
  • Ischemic heart disease (IHD)
  • Hypertensive heart disease
  • Rheumatic heart disease (RHD)
  • Thyrotoxicosis
  • Post-srugery
  • Chronic lung disease
  • Atrial septal defects (ASD)
  • Acute alcohol intoxication

2. In CVA patient, we need to rule out causes of cardiogenic embolism on ECG
  • Artrial fibrillation (AF): Absence of P-wave, irregular base line, irregular RRI.
  • Myocardial infarction (MI): Deep Q-wave.
  • Left ventrial aneurysm: Residual ST-elevation, deep Q-wave.

3. Orange-coloured urine is SE of Rifampicin. Need to explain that this medication may produce orange coloration of urine, sweat, saliva, or tears, but it is harmless, so reassure patient to continue to take their medication.

Sunday, January 15, 2012

Heart rate, Finger clubing, DOTS

1. What is the fastest, most common, efficient way to calculate the heart rate from ECG? (Hint: number 300)
2. How to diagnose finger clubbing and how to stage the finger clubbing? What are the possible cardiovascular causes of finger clubbing? (Hint: one of the test-> diamond window)
3. Once a patient is diagnosed TB, he/she has to follow DOTS. What is DOTS? He/she will given a small recordable TB book and there are 2 kinds of color for it. There will be white and yellow in color. What does the color mean? (Hint: the color has to do with sputum AFB)

1. Calculating heart rate (HR) from ECG

The most common way to calculate HR from ECG is by taking 300 and divide it RR interval (RRI) (represented by number of big boxes).
e.g. The RRI is 4 big boxes, so the HR = 300/4 = 75 beats per min (bpm).

If the patient has very fast HR and the RRI might be less than even 1 big boxes, HR can be calculated by taking 1500 and divide it by RRI (represented by number of small boxes).
e.g. The RRI is 4 small boxes, so HR = 1500/4 = 375 bpm.

However, personally I found out that the fastest and most efficient way to calculate HR is the triplet method. First memorise these 2 triplets:

300-150-100
75-60-50

Then try to find a R wave on a black line, then start counting the black lines after that R wave until u meet the next R wave. When you count, don't count by mentioning "1-2-3-4......", rather you should count by mentioning the triplets that you memorise, i.e. "300-150-100-75.....". So when the number of the black line that you mentioned hit the next R wave, that's the HR. I hope the illustration below helps to understand this concept.


You can make the most out of this triplets method by further memorised the numbers in between those triplets. This become handy when the next R wave falls in between the 2 black lines.

300-200-150-120-100-85
75-65-60-55-50-45

For e.g. when the next R wave falls in between the lines represent 300 and 150, so we can straight away know the HR = 200 bpm.


This method is efficient because it saves the trouble of calculating difficult mathematics, eg 300 divided by1.5 boxes, or 300 divided by 2.5 (either with your mind or with a calculator or the calculator in the handphone).

2. Finger / Digital Clubbing: There are 4 stages of finger clubbing.
  1. Increased glossiness and cyanosis at the skin of the root of nail with increased fluctuation at the base of the nail bed. 
  2. Lovinbond's sign : loss / reverse of hyponychial angle (angle between nail and nail bed).
  3. Hippocratic finger / Parrot beak / Drum-stick: increased anterior-posterior (AP) curvature.
  4. Hypertrophic osteoarthopathy (HOA).
  • Schamroth's window test: bring the fingers from side together, with the nail facing each other. Loss of the kite-shaped window between the nail indicates finger clubbing.

  • Interphalangeal depth ratio: DPD/IPD > 1 indicates finger clubbing.
    DPD : distant phalangeal depth, AP dimension measured at hyponychial angle.
    IPD : interphalangeal depth, AP dimension measured at the distal interphalangeal joint (DIPJ)

  • Elicit fluctuation: I stage of clubbing can be checked by palpating the nail bed with both hands: 2 thumbs below the patient's finger; while 2 index fingers above the patient's finger, near the tip; 2 middle fingers above the patient's finger, at the end of the nail bed. Use your middle fingers to press the nail bed, check whether the distal part of the nail is fluctuating / ballotable.

Summary of the examination for digital clubbing
  1. View the fingers from a dorsal and lateral view. Note the width of terminal portion and compare with the proximal part.
  2. Look at the angle between the nail and skin (Schamroth's window test)
  3. Inspect the periungual skin. Check for cyanosis, shiny, or stretched skin.
  4. Elicit fluctuation of the nail bed.
  5. Attempt to feel the posterior edge of nail.

Cardiac cause of finger clubbing: infective endocarditis (IE), cyanotic heart disease.
Need to exclude GI and respiratory cause: e.g. liver cirrhosis, bronchial CA.


3. DOTS is Directly Observed Treatment, Short-course. Consists of 5 elements:
  1. Government commitment.
  2. Detect case with sputum AFB of TB patients.
  3. Standard short course of 6/12 TB treatment, with trained supervisor watching patients swallow their anti-TB drugs. DOTS is used with intermittent dosing (thrice weekly). 
  4. Regular anti-TB drugs supply.
  5. Monitor and report treatment outcome.
Not quite sure about the white and yellow booklet. Anyway this is my guess. Since the patient's sputum AFB need to be checked, so the booklet should be used to record the result of sputum AFB. Since only one booklet is given, and the container for sputum AFB collection is yellow in colour, so the yellow book should be given for patient with smear +ve PTB, while white book should be given to patient with smear -ve PTB. This is just my guess.

--- UPDATE ---

Stage of finger clubbing
I. Fluctuation and softening of finger nail bed
II. Loss of normal angle (Lovinbond's angle)
III. Increased convexity of nailbed
IV. Thickening of whole distal part of finger nail
V. Shiny aspect and striation of nail and skin (HPO)

Causes of FC with CVS origin
1. Artrial myoma
2. Cardiovascular disease with hypoxia
3. Congenital heart disease
4. Infective endocarditis

DOTS is directly observed therapy, short course
What you mentioned about DOTS is right. After a patient is diagnosed TB, he/she needs to come to KK(Klinik Kesihatan) to claim anti-TB medication daily, so that we can make sure the patient is taking medication.
White DOTS book means "smear -ve TB" and yellow one means "smear +ve TB".


Additional question: a senior MO asked me this question.
What are the two types of finger clubbing? (Hint: stage III of clubbing)

Types of finger clubbing:
  1. Parrot-beak
  2. Drumstick
According to that MO, certain type of clubbing is more common or dominant in certain diseases, due to different pathogenesis or mechanism. He wants me to find the answers myself, but honestly after I searched for few days still can't find the answer. Apparently this information is something that he learnt in India, since he graduated from there, and he asked me to find in Indian website.

Thursday, January 12, 2012

2ICS & PTB

1. What is the correct way to identify the second intercostal space? (Hint: sternal angle)
2. What are the criteria to diagnosis PTB (pulmonary tuberculosis)? (Hint: 2/3 criteria)
3. What is TB intensive and maintenance/continuation phase? (hint: type of medication and duration)

1. Second intercostal space:
  • The angle of Louis / sternal angle is a useful place to start counting ribs, which helps localize a respiratory finding horizontally. If you find the sternal notch, walk your fingers down the manubrium a few centimeters until you feel a distinct bony ridge. This is the sternal angle. The 2nd rib is continuous with the sternal angle, slide your finger down to localize the 2nd intercostal space.
  • The angle of Louis also marks the site of bifurcation of the trachea into the right and left main bronchi and corresponds with the upper border of the atria of the heart.

2. Diagnosis criteria of PTB (2/3):
  1. Clinical picture of PTB: cough >2-3/52, fever, LOW, +/- hemoptysis
  2. CXR signs of PTB: Upper lobes consolidation / cavitation
  3. Sputum AFB (+): 3 x early morning sputum is collected on first day, subsequent 1 x early morning sputum for another 3/7.
However, before diagnosis can be put as PTB, we can consider whether to give anti-TB drugs after collecting the sputum. Signs that suggest PTB (but not enough to diagnose it):
  • Clinical picture of PTB
  • CXR signs of PTB
  • FBC changes: ↑ Monocyte, ↑ Platete, ↑ ESR

If the above signs are fulfilled, it is highly suggestive for PTB, and anti-TB drugs can be given after sputum is collected. Remember to check for serum Na+ to exclude SIADH. 

3. TB treatment:
  • Intensive phase of refer to the initial phase of TB treatment, 2/12 duration, on 4 anti-TB drugs. Aims: Eliminate clinical picture of TB, eliminate MTB in sputum, and prevent development of drug resistance.

    e.g. 2HRZE or 2HRZS

  • Maintenance/continuation phase refer to the second phase of TB treatment, 4-7/12 duration, on 2 anti-TB drugs. Aims: Suppress MTB in host, and prevent relapse of TB.

    e.g. 4HR or 4(HR)3

--- UPDATE ---
 
Answers:

1. The sternal angle is between the manubrium and sternum. Once you identify the location by palpation, the left second rib is just beside it. Your finger moves along the second rib and move down below it. There the second intercostal space is localized. The importance of localization of second intercostal space is to do pleurocentesis, chest tube insertion and etc.

2. The criteria of PTB diagnosis:
a. Clinical symptoms
b. CXR findings
c. Sputum AFB(acid fast bacilli)
  • Clinical symptoms: in your clerking, you must ask duration of cough, hemoptysis, evening rising temperature, night sweat, LOA/LOW (loss of appetite and loss of weight), h/o (history of) contact with PTB patients, h/o PTB in the past, risk factor (e.g DM, IVDU/Intravenous drug user, RVD+ve/retroviral disease +ve, so on). The symptoms must be more than 2 weeks duration.
  • CXR findings: cavitation/haziness over upper zone/apical region of lung field.
  • Sputum AFB: collection must be done x OD x 3/7

REMEMBER: to diagnose PTB, we need 2 out of 3 criteria.
TB is divided into PTB and EPTB (extrapulmonary PTB). PTB can be smear positive and smear negative.
Even sputum AFB is negative, with 2 other criteria, evidence is enough to label a patient with smear negative PTB. Smear positive PTB is PTB with sputum AFB +ve.
Note: sputum AFB is not sputum MTB.

3. TB intensive phase usually requires 2 months or 56 doses. The initial phase can be extended up to maximum, 84 doses, depending on the patient's condition. During this phase, the standard TB medication would be EHRZ / Ethambuthol + Isoniazid + Rifampicin + Pyrazinamide.
Then the latter phase would be continuation/maintenance phase. During this phase, the standard anti-TB medication would be H (Isoniazid) and R (Rifampicin). It is given at least 6 months.

You must know the common side effect of PTB medication.
  • E - 15-25mg/kg/day; max 1200mg
    common SE- optic neuritis
    contraindicated for the patient with advanced age > 70 years old and age < 15 years old, poor vision, renal impairment.
  • H - 5mg/kg/day; max 300mg
    common SE- liver impairment, skin rash.
  • R - 10mg/kg/day; max 600mg
    common SE- liver impairment, acute renal failure, thrombocytopenia, drug-induced jaundice
  • Z - 25mg/kg/day; max 1500mg
    common SE- liver impairment, hyperuricemia
S(Streptomycin)- used when it is indicated. Usually it is given for TAI (treatment after interruption), relapsed TB, reactivation of TB. Common SE- renal impairment, ototoxicity. It is contraindicated in age > 60 and in children, pregnancy.

Another way of TB prescription according to weight. It is used by chest physician in Kedah.
  • S - Streptomycin
    0.75mg OD if BW > 30kg;
    0.5mg OD if BW < 30kg
  • H - Isoniazid
    300mg OD
  • R - Rifampicin
    600mg OD if BW > 50kg;
    450mg OD if BW 30-50kg and
    300mg OD if BW < 30kg
  • Z - Pyrazinamide
    1500mg OD if BW >40-50kg;
    1250mg OD if BW 30-40kg and
    1000mg OD if BW < 30kg
  • E - Ethambutol
    by practise 1400mg OD up to maximum 2600mg OD and we calculate 25mg/kg/day for E
TB medication is mainly prescribed by chest MO; however we need to know the usual dosage.

TB is the second main infectious disease after Dengue fever.



Additional Question:
What are signs of TB of CNS on neuroimaging? (There should be 5)

  1. Tuberculoma: non-enhancing and enhancing.
  2. Infarct: caused by vasculitis after being insulted by TB granulation tissue
  3. Hydrocephalus: communicating and non-communicating
  4. Meningeal enhancement, especially basal enhancement
Not sure about the last sign, but might be the following:
  1. Cerebral abscess: rare complication
  2. Cerebritis with enhancement at cerebral parenchyma
  3. Granulation tissue in basal cistern, superficial sulcal spaces, Sylvian fissure
     → Isodense or mildly hyperdense exudate obliterates the basal cistern.
  4. Cerebral oedema

Tuesday, January 10, 2012

Cardiomegaly, OHA, Hypoglycemia

1. What is the criteria to say a patient to have cardiomegaly based on CXR? (clue: cardiothoracic ratio)
2. If you are working in district hospital as a MO, would you give OHA to a pregnant woman? Why not?
3. A patient came to you with hypoglycemia. His DXT was 2.0mmol/L. For the past 5/7, he c/o (complaint of) dysuria and increased frequency of micturination, vomiting and low grade fever x 5/7. He noted his urine was cloudy. He claimed that daily he took 2 types of OHA - one was round-shaped,(roughly) 1cm sized white tablet and another one is small, oval shaped white tablet.
Q:
a. What would be your complete diagnosis then?
b. Let us guess what OHA he was taking, based on his description of the OHA tablets.
c. What would be your first step when the patient's DXT 2.0mmol/L and he is unconscious.

1. Cardiomegaly's criteria on CXR: When Cardiothoracic ratio > 0.5, i.e. the maximal transverse diametre of heart is >50% of the maximal transverse diametre of the thoracic cavity.

2. OHA shouldn't be given to pregnant woman as there are no data regarding safety of OHA usage in pregnant women. If the DXT is uncontrolled by diet and exercise then insulin is considered to control DM during pregnancy.

3. Hypoglycemia

a. Diagnosis: Hypoglycemic attack secondary to UTI. 
Although infection is the usually cause for hyperglycemia due to increased requirement of insulin, but infection can cause hypoglycemia by the following causes:
  • Infection causes loss of appetite (LOA) and cause patient reduces food intake.
  • Infection causes decrease of DXT by increased metabolism.
These result in relative insulin overdose if the patient still take the same dose of OHAs.

b. Possible OHA is metformin and glicazide or glibenclamide, as these drugs are white tablets, available in either round or oval shape, and the combination of metformin + sulfonylurea is a common treatment.

c. Immediate action to restore back the DXT to normal is needed. Dextrose 50% 25-50ml IV till recovering of consciousness, followed by D5 infusion or glucose drink PO. If IV access not possible, can consider glucagon 1mg IM / SC. 


--- UPDATE ---
 
Answer.
1. Cardiothoracic ratio will determine whether a patient to have cardiomegaly. Normal CTR should be less than 0.5. In the CXR, we take the length of heart and length of whole thorax in longitudinal direction. Then we divide the cardiac length with thoracic one. If the value exceeds 0.5, then it is cardiomegaly. Do remember that we can only measure CTR from CXR in PA erect. CXR in supine PA or AP can give you wrong view of heart position.
2. OHA is recommended for pregnant women. Firstly blood sugar must be controlled well during pregnancy to prevent hyperglycemic complications. (You shall find out about it-> polyamnio, congenital defects, macrosomia, post-partum fetal hypoglycemia etc. You also must know how post-delivery fetal hypoglycemia can develop and how to prevent it post-partumly.) Secondly, OHA may have teratogenic effect but it is not completely proven.
3. (hint: DXT means dextrostick. )
a. Diagnosis would be Hypoglycemic attack secondary to UTI(urinary tract infection).
b. White rough big tablet is metformin; usually small round tablet is gliclazide. Sometimes, gliclazide is small oval-shaped. Most of the time, glibenclamide is small oval shaped. All of them are white in colour.
c. If a patient develops hypoglycemic attack and is unconscious, we must give intravenous(IV) bolus Dextrose 50%(D50%) 50cc. IV D50% is given till the patient regains consciousness. Then we must maintain the blood sugar level with IV drip D10%/D5% (depending on the DXT). IM glucagon can be given if there is no IV access.
(You shall find out what is neuroglucopenia)