Friday, June 30, 2017

Q: What is the clinical utility of "Spin echo imaging" in cardiac magnetic resonance imaging (MRI)? 


 Answer: Cardiac MRI is an umbrella term for various methods to utilize it to evaluate various functions of heart like Spin echo imaging, Steady state free precession imaging, Flow velocity encoding, Magnetic resonance spectroscopy. 

Spin echo imaging shows the tissue structures of the heart as bright and the blood as dark. It provides details of anatomical imaging, and identify the fatty infiltration of the right ventricular free wall to evaluate arrhythmogenic right ventricular cardiomyopathy (ARVC).


Reference:


Menghetti L, Basso C, Nava A, et al. Spin-echo nuclear magnetic resonance for tissue characterisation in arrhythmogenic right ventricular cardiomyopathy. Heart 1996; 76:467.

Thursday, June 29, 2017

Q: What is  “Dead Donor Rule” (DDR)?

Answer: DDR seems simple but it continued to remain a controversial point in medical ethics. DDR implies that a person must be dead before their organs can be taken. This death is considered to be determined by cardiocirculatory criteria,  according to which life-support is withdrawn, an specific time interval of the monitored absence of pulse, blood pressure, and respiration observed, and then death declared. The most accepted time interval in US is according to The Pittsburgh Protocol which requires 2 minutes.


Reference:

Bernat JL (2008). "The boundaries of organ donation after circulatory death". New England Journal of Medicine. 359 (7): 671.

Wednesday, June 28, 2017

Q: Within how many days the resolution of thrombocytopenia should be apparent following withdrawal of heparin in Heparin Induced Thrombocytopeni (HIT)?


Answer:  Within seven days

Though academically seven days are said for the resolution of thrombocytopenia following withdrawal of heparin in HIT patients but pragmatically a trend towards improving platelet count should start happening within three to four days - and if not suspicion for other causes or continue heparin exposure should be looked for.

Tuesday, June 27, 2017

Monday, June 26, 2017

Q; In patients undergoing abdominal aortic aneurysm repair, where is livedo reticularis is usually located?


Answer: Livedo reticularis due to cholesterol emboli is usually found on the feet and lower legs but in patients undergoing abdominal aortic aneurysm (AAA) repair, livedo reticularis may be found on the back and the buttocks. This is due to the involvement of branches of the internal iliac arteries.

Sunday, June 25, 2017

Q: Why  wound deformation is desired in Negative pressure wound therapy (NPWT) (Wound-vac)?


Answer: The negative pressure  in NPWT deforms the edges of the wound together and firmly apposes any skin grafts/flaps. Tissue deformation stimulates tissue remodeling at the cellular level.



References:

Urschel JD, Scott PG, Williams HT. The effect of mechanical stress on soft and hard tissue repair; a review. Br J Plast Surg 1988; 41:182.

Saturday, June 24, 2017

Q: What are the five Key features of alcoholic hallucinosis?


Answer: Alcoholic hallucinosis (AH)  is a different clinical scenario from delirium tremens (DT) with following key features

  1. The onset of AH is usually between 12 to 24 hours of alcohol abstinence and tends to resolve within 24 to 48 hours. In contrast, DT starts around 48-72 hours.
  2. AH has mostly visual hallucinations (auditory and tactile hallucinations are less frequent)
  3. Patients are aware that they are hallucinating!
  4. AH is not associated with delirium - unlike DT, and it is a hallucination specific phenomenon.
  5. It does not effect hemodynamics.


Friday, June 23, 2017

Q; How much ice saline should be arranged at bedside, if 'iced saline lavage' is planned for the management of massive hemoptysis?


Answer: About one Liter

Multiple strategies have been tried and tested in nerve wrecking event of massive hemoptysis including balloon tamponade, topical medications, laser therapy, electrocautery and iced saline lavage. In case, iced saline lavage is planned Twenty 50 mL syringes of iced saline should be collected at bedside for lavage. Though it may require less amount of iced saline before blleding source seems quiet but recommended amount for such procedure is about 1000 cc. 




Reference:

 AA Conlan. Management of massive hemoptysis with the rigid bronchoscope and cold saline lavage.Thorax,Vol 35,901–904.

Thursday, June 22, 2017

Q; Which statement is true regarding dexmedetomidine?


A) Drugs that lower systemic blood pressure may enhance dexmedetomidine's hypotensive effect

B)  Drugs that increase systemic blood pressure may enhance dexmedetomidine's hypertensive effect

C) Both of the above


Answer:  C

Dexmedetomidine is one of the unique sedative which has both hypotensive as well as hypertensive property. Hypertensive property is usually evident with bolus administration and hypotensive effects may be apparent during slow infusion. Similarly, it can have synergistic effect with similar kind of drugs. It is metabolized by glucuronidation and cytochrome P450.



Reference:

Chen K, Lu Z, Xin YC, et al. Alpha-2 agonists for long-term sedation during mechanical ventilation in critically ill patients. Cochrane Database Syst Rev 2015; 1:CD010269.

Wednesday, June 21, 2017

Q: 78 year old male with Abdominal Endovascular Aneurysm Repair (EVAR) in the morning for his Abdominal Aortic Aneurysm (AAA) complained of acute abdomen and diagnosed with acute ischemic colitis. Patient is taken to OR for emergent surgery and required colectomy. Primary anastomosis should be performed and abdomen should be closed to avoid vascular graft infection?

A) True
B) False


Answer: False (B)

On the contrary, in patients with  with an aortic or iliac vascular graft, primary anastomosis should be avoided because any subsequent anastomotic leak would contaminate the graft. As per clinical situation, abdomen can be left open and should be taken within 24 hours for second-look procedure.


Reference:

1. Betzler M. [Surgical technical guidelines in intestinal ischemia]. Chirurg 1998; 69:1.

2. Hanisch E, Schmandra TC, Encke A. Surgical strategies -- anastomosis or stoma, a second look -- when and why? Langenbecks Arch Surg 1999; 384:239.

Tuesday, June 20, 2017

Q: Which antibiotic is suggested in the management of Abdominal Aortic Aneurysm (AAA)?


Answer: Doxycycline

Historically, it was postulated that AAA expansion may be due to the result of Chlamydia pneumoniae infection, and antibiotics were suggested to attenuate their expansion. Though some animal models and small studies have shown possible positive impact but so far evidence is extremely weak for its use as a standard of care in humans.



References:

1. Chung AW, Yang HH, Radomski MW, van Breemen C. Long-term doxycycline is more effective than atenolol to prevent thoracic aortic aneurysm in marfan syndrome through the inhibition of matrix metalloproteinase-2 and -9. Circ Res 2008; 102:e73.

2. Preoperative treatment with doxycycline reduces aortic wall expression and activation of matrix metalloproteinases in patients with abdominal aortic aneurysms. J Vasc Surg 2000; 31:325.

3. Baxter BT, Pearce WH, Waltke EA, et al. Prolonged administration of doxycycline in patients with small asymptomatic abdominal aortic aneurysms: report of a prospective (Phase II) multicenter study. J Vasc Surg 2002; 36:1. 

4. Petrinec D, Liao S, Holmes DR, et al. Doxycycline inhibition of aneurysmal degeneration in an elastase-induced rat model of abdominal aortic aneurysm: preservation of aortic elastin associated with suppressed production of 92 kD gelatinase. J Vasc Surg 1996; 23:336. 

5. Clinical trial of doxycycline for matrix metalloproteinase-9 inhibition in patients with an abdominal aneurysm: doxycycline selectively depletes aortic wall neutrophils and cytotoxic T cells. Circulation 2009; 119:2209. 

6. Meijer CA, Stijnen T, Wasser MN, et al. Doxycycline for stabilization of abdominal aortic aneurysms: a randomized trial. Ann Intern Med 2013; 159:815. 

Sunday, June 18, 2017

Q: Asymmetric flaccid paralysis is a hallmark of 

 A) HIV Meningitis 
 B) mumps meningitis 
C) HSV meningitis
D) Bacterial meningitis 
E) West Nile virus meningitis


Answer:

Meningitis due to West Nile virus is unique in the sense that one of its clinical symptom is asymmetric flaccid paralysis!


Related article:  Greg Kraushaar, Rajesh Patel and Grant W. Stoneham - West Nile Virus: A Case Report with Flaccid Paralysis and Cervical Spinal Cord MR Imaging Findings - American Journal of Neuroradiology January 2005, 26 (1) 26-29;

weblink: http://www.ajnr.org/content/26/1/26

 Reference: 

Centers for Disease Control and Prevention. Acute flaccid paralysis syndrome associated with West Nile virus infection--Mississippi and Louisiana, July-August 2002. MMWR Morb Mortal Wkly Rep. 2002 Sep 20. 51(37):825-8.

Saturday, June 17, 2017

Q: For seizure, If IV access is not available, midazolam can be given all of the following routes except

A) Intra-Muscular (IM)
B) Nasally
C) Buccally
D) Rectally


Answer:  D
If IV access is not available, midazolam is a preferred benzodiazepine. which can be given in a dose of 10 mg as IM, nasally or buccally. Theoretically nasal and buccal routes may be more quicker in action. 

Valproate is the only anti-seizure drug which can be given rectally.


References:

1. Arya R, Kothari H, Zhang Z, et al. Efficacy of nonvenous medications for acute convulsive seizures: A network meta-analysis. Neurology 2015; 85:1859. 

2. Hirsch LJ. Intramuscular versus intravenous benzodiazepines for prehospital treatment of status epilepticus. N Engl J Med 2012; 366:659.

Friday, June 16, 2017

CRRT circuit on ECMO

Following is the simple diagram to understand where to insert CRRT lines while patient on ECMO. It helps in decreasing the extra line access.

Click to enlarge



Thursday, June 15, 2017

Q: What is the most essential first step for the examination of spleen?


Answer: Not always appreciated but the most important and first step in the exam of spleen is the relaxation of the examiner's hands. If examiners' hand is not relaxed and sudden pressure is applied, patient may feel unbearable pain and further examination may become difficult. Examiner should first put his hands softly after explaining to patient and let patient acclimatize to hands.  

Also, by placing patient gently in the right lateral decubitus position (+/-), with knees and neck flexed may make exam easy. This helps to rotate the spleen to a more anterior position.

Wednesday, June 14, 2017

Q: How the dynamic hepatic clearance test is measured?

Answer: The dynamic hepatic clearance test is also known as the indocyanine green plasma disappearance rate (ICG-PDR). LFT (liver enzymes) and hepatic protein synthesis has limited diagnostic sensitivity for hepatic dysfunction in ICU patients. ICG-PDR is found to be better correlated in critically ill patients.

Indocyanine green (ICG) (compound) is injected in the central venous catheter. Dose is 0.5 mg/kg. ICG is exclusively eliminated by the liver unconjugatedly into the bile and does not undergo enterohepatic recirculation. Its removal from the blood depends on liver blood flow, parenchymal cellular function, and biliary excretion.

Its elimination is expressed as the plasma disappearance rate (ICG-PDR) and  is measured non-invasively at the bedside by transcutaneous pulse densitometry with a finger clip. Normal values for ICG-PDR are considered to be more than 18% per minute. 


 References: 

1. Kimura S, Yoshioka T, Shibuya M, Sakano T, Tanaka R, Matsuyama S. Indocyanine green elimination rate detects hepatocellular dysfunction early in septic shock and correlates with survival. Crit Care Med. 2001;29:1159–1163.

2. Sakka SG, Reinhart K, Wegscheider K, Meier-Hellmann A. Comparison of cardiac output and circulatory blood volumes by transpulmonary thermo-dye dilution and transcutaneous indocyanine green measurement in critically ill patients. Chest. 2002;121:559–565.

Tuesday, June 13, 2017

Q: Which of the following contraindicates use of citrate in Continuous Renal Replacement Therapy (CRRT)?

A) Hepatic failure
B) severe Thrombocytopenia
C) DIsseminated Intravascular coagulation (DIC)
D) Requirement of pressor
E) Femoral access for CRRT


Answer: A

Citrate is used in CRRT to provide regional anticoagulation. It works by chelating ionized calcium and consequently prevents coagulation cascade. Though most of the calcium citrate complex is removed by filter, but still clinically significant amount reaches the body. Citrate gets metabolized to bicarbonate by the liver. Each citrate molecule produces three bicarbonate molecules. Citrate should not be used in patients with hepatic failure, because accumulation of citrate may cause life-threatening hypocalcemia by binding to ionized calcium in the body. Instead of LFT, it has been proposed to use prothrombin time or lactate level as predictor of potential citrate toxicity with less than 26 percent and more than 3.4 mmol/L respectively.

All other choices (B, C, D and E) have no effect on citrate.



References:

1. Apsner R, Schwarzenhofer M, Derfler K, et al. Impairment of citrate metabolism in acute hepatic failure. Wien Klin Wochenschr 1997; 109:123. 

2. Kramer L, Bauer E, Joukhadar C, et al. Citrate pharmacokinetics and metabolism in cirrhotic and noncirrhotic critically ill patients. Crit Care Med 2003; 31:2450. 

3. Schultheiß C, Saugel B, Phillip V, et al. Continuous venovenous hemodialysis with regional citrate anticoagulation in patients with liver failure: a prospective observational study. Crit Care 2012; 16:R162.

Monday, June 12, 2017

Q: 52 year old male is admitted with severe sepsis two days after dog bite. After admission, lab called to inform you that patient's blood smear showed Howell-Jolly bodies. What part of the history should be evaluated again?


Answer: Previous splenic injury

Unusual as well as rapid deterioration with sepsis should bring forward the question of hyposplenism. In Dog bites, rapid sepsis often due to capnocytophaga canimorsus (gram negative rods) should raise the probability of previous splenic pathology. Blood smears usually demonstrate Howell-Jolly bodies in the erythrocytes of asplenic and in patients with functional hyposplenism.

Saturday, June 10, 2017

Q; What is the usual rate of unplanned extubations in ICUs?


Answer:   3 to 12 percent

Though desire is to have no unplanned extubation in ICU. But given that spontaneous breathing trials, stopping of sedation, early mobilization are more desired in ICU - expecting no unplanned extubation would be impossible. Data shows that ICUs have anywhere from 3-12 percent.


References:

1. de Groot RI, Dekkers OM, Herold IH, et al. Risk factors and outcomes after unplanned extubations on the ICU: a case-control study. Crit Care 2011; 15:R19. 

Friday, June 9, 2017

Q: 45 year old man is in ICU and going for PET scan for unrelated reason. Radiology department ask you to administer IV Lorazepam if feasible before PET scan. What is the reason behind it?


Answer: Brown adipose tissue in the body  can cause increase uptake of fluorodeoxyglucose (FDG) and give false positive results Brown tissue is usually found at the base of the neck, in the supraclavicular region, in the superior mediastinum, and in the upper abdomen. Benzodiazepines decreases the sympathetic tone, and reduces the metabolism of brown fat, and helps in decreasing the likelihood of false positive results of PET scan.


References: 

O'Donnell JS, Rini J, Chusid J, Shah R. Abnormal Uptake on PET/CT: Imitators of Malignancy in Thoracic Imaging. Contemporary Diagnostic Radiology 2011; 34:1.

Thursday, June 8, 2017

Q; 52 year old male who is admitted in ICU for unrelated reason went to have cystoscopy for hematuria and found to have bladder tumor. Why it is necessary to scan ureters and renal pelvises for malignancy too? 


 Answer: If urinary bladder tumor get diagnosed, the upper tracts (pelvis and ureter) should also be scanned as they also carry transitional epithelium. This is called a field cancerization effect for urothelial tumors.



References:

1. Am J Surg Pathol 2004; 28:1545. Herr HW, Cookson MS, Soloway SM. Upper tract tumors in patients with primary bladder cancer followed for 15 years. J Urol 1996; 156:1286.

Wednesday, June 7, 2017

Q: During institution of prone position, care should be taken to support the abdomen while patient stays prone? 

 A) True 
B) False


Answer: B

Actually, on application of prone position in ARDS,  patient's abdomen should be left unsupported to decrease effect of intra-abdominal pressure. Only thorax should be supported. Unsupported abdomen and supported thorax (making heart dependent) results in its benefit. More homogeneous Ppl gradient in ventrodorsal and cephalocaudal planes improves the ventilation distribution, resulting in more homogeneous perfusion. And, smaller volume of dependent lung decreases the shunting.


Tuesday, June 6, 2017

Q: 54 year old male is brought  to ICU with acute alcohol intoxication. Intravenous thiamine is  quickly administrated to patient prior to dextrose, but patient went into impending respiratory failure with severe audible wheezing. Your diagnosis?


Answer: Bronchospasm from Thiamine administration.

Thiamine is usually a very safe medicine but can have a rare occurrence of anaphylaxis and bronchospasm. Though, it may be more of an academic interest but astute clinician should always keep in mind the possible adverse effects even of usually safe drugs.



Reference: 

Cook, C. C. H., Hallwood, P. M. and Thomson, A. D. (1998) B vitamin deficiency and neuropsychiatric syndromes in alcohol misuse. Alcohol and Alcoholism 33, 317–336.

Monday, June 5, 2017

Q: Why it is advisable to give parenteral administration (IV or IM) of thiamine to prevent wernicke encephalopathy (WE) in patients presented with alcohol intoxication or severe malnourishment?



Answer: 

Three things should be considered while giving thiamine to prevent WE.

1. Gastrointestinal (GI) absorption of thiamine is erratic, particularly in alcoholic and malnourished patients.

2.  Thiamine should be given before glucose, as glucose without thiamine can precipitate or worsen WE.

3. Some patients have genetically determined requirement for much higher doses of thiamine. As thiamine is safe, cheap in cost, and very effective, there is usually no harm to stay towards higher side of dosing.



 References: 

1. Galvin R, BrÃ¥then G, Ivashynka A, et al. EFNS guidelines for diagnosis, therapy and prevention of Wernicke encephalopathy. Eur J Neurol 2010; 17:1408. 

2. Wrenn KD, Murphy F, Slovis CM. A toxicity study of parenteral thiamine hydrochloride. Ann Emerg Med 1989; 18:867. 

3. Agabio R. Thiamine administration in alcohol-dependent patients. Alcohol Alcohol 2005; 40:155.

4. Thomson AD, Cook CC, Touquet R, et al. The Royal College of Physicians report on alcohol: guidelines for managing Wernicke's encephalopathy in the accident and Emergency Department. Alcohol Alcohol 2002; 37:513. 

5. Day E, Bentham P, Callaghan R, et al. Thiamine for Wernicke-Korsakoff Syndrome in people at risk from alcohol abuse. 

Sunday, June 4, 2017

Q: 72 years old male is admitted to ICU with CVA. Urology service is consulted for urinary catheter insertion. After evaluation they recommend ureteral stent. On reviewing the chart, you note that patient has a diagnosis of Heparin Induced Thrombocytopenia (HIT) in the chart. What advise should be shared with urology service?


Answer:  Avoid stent with heparin coating

Different commercial ureteral stents are available with coating of hydrogel, heparin, silver nitrate, or ofloxacin. In patients, with diagnosis it is advisable to avoid any type of exposure to heparin if there is no absolute need.


References:

1. Riedl CR, Witkowski M, Plas E, Pflueger H. Heparin coating reduces encrustation of ureteral stents: a preliminary report. Int J Antimicrob Agents 2002; 19:507. 

2. Tenke P, Riedl CR, Jones GL, et al. Bacterial biofilm formation on urologic devices and heparin coating as preventive strategy. Int J Antimicrob Agents 2004; 23 Suppl 1:S67. 

Saturday, June 3, 2017

Q: All of the following should be considered as a comfort measure in last stage of idiopathic Pulmonary Fibrosis (IPF) except?

A) Facial cooling 
B) Opiates
C) Benzodiazepines, 
D) Non-Invasive ventilation (NIPPV)
E) Palliation of cough symptoms


Answer: D

Unfortunately in terminal IPF, invasive or non-invasive ventilation is of not much help. Non-invasive mechanical ventilation is of limited help. If comfort measures are in process, NIPPV should be used only in case to case basis, with clear explanation to patient and family that though it may improve oxygenation but may not help in time to death. Surprisingly, most patients understands and agree on against use of NIPPV.


NIPPV though may help in patients where there is a hope in relief and resolution of acute exacerbation of IPF or resolution of underlying pneumonia.



Friday, June 2, 2017

Q: 44 year old male is admitted to ICU for probable liver transplantation. On arrival in ICU lab work showed Sodium of 124 meq/L. You next plan

A) Do not treat
B) Administer normal isotonic saline
C) Administer hypertonic saline
D) Repeat sodium again to re-confirm the value
E) Administer Tolvaptan


Answer:  C

Treatment with hypertonic saline is strongly recommended in patients who arrive in ICU for liver transplantation and found to have severe hyponatremia. But care should be taken to avoid rapid correction as it may cause central pontine and extrapontine myelinolysis, and partial correction is recommended. Restoration of liver function following liver transplant corrects previously and partially corrects hyponatremia, and found to provide survival benefit.

To note, (Choice E) Tolaptan is strongly discouraged in cirrhosis patient due to its effect on kidney, causing renal failure.


References:

1. Yun BC, Kim WR, Benson JT, et al. Impact of pretransplant hyponatremia on outcome following liver transplantation. Hepatology 2009; 49:1610.

Thursday, June 1, 2017

Q: Sotalol is contra-indicated or should be used with extreme caution as it may cause sudden cardiac death in? 

 A) Liver failure
B) Renal failure
C) Ejection fraction less than 20%
D) In patients with mechanical valves
E) along with metformin


Answer: B


Risk of sotalol in renal failure is known since more than 40 years. It should be used in renal failure only by experienced hands!


References: 

1. Sundquist HK, Anttila M, Forsström J, Kasanen A. - Serum levels and half-life of sotalol in chronic renal failure. - Ann Clin Res. 1975 Dec;7(6):442-6. 


2. Bathen J, Madsen S. - Sotalol--atrial fibrillation, reduced renal function and sudden death - Tidsskr Nor Laegeforen. 1998 Oct 30;118(26):4086-7.