Langer's Lines

Q: What are Langer's lines?

Answer: Langer lines are actually skin tension lines. They represent the map of the direction in which the tension in the skin is maximal at different body sites. They were first described by Karl Langer in 1861. They have significant clinical implications in surgery and trauma for the design and placement of surgical incisions. They also help to determine the patterns of spread of some skin disorders. In facial trauma, lacerations not parallel to Langer's lines tend to develop more prominent scarring.

#surgical-critical-care

#trauma

#dermatology

References:

1. Karl Langer, "Zur Anatomie und Physiologie der Haut. Über die Spaltbarkeit der Cutis". Sitzungsbericht der Mathematisch-naturwissenschaftlichen Classe der Wiener Kaiserlichen Academie der Wissenschaften Abt. 44 (1861)

2.  "Method and apparatus for determining the lines of optimal direction for surgical cuts in the human skin - US Patent 6418339". Archived from the original on 2013-04-21.

3. Wilhelmi BJ, Blackwell SJ, Phillips LG (July 1999). "Langer's lines: to use or not to use". Plast. Reconstr. Surg. 104 (1): 208–14

*picture: José María Arribas Blanco, Shabnan Habibi, Nuria Rodríguez Pata and José Ramón Castello - (2016). "Integrated Activities in Primary Care – Minor Surgery in Family Medicine". IntechOpen. DOI:10.5772/62650. "This chapter is distributed under the terms of the Creative Commons Attribution 3.0 License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited."

PAC in FES

Q: 28 years old male is admitted to trauma ICU after a motor vehicle accident (MVA) with high probability of fat embolism. A pulmonary artery catheter (PAC) is floated. Wedged sample from the distal port of PAC failed to show any fat globules. This excludes the diagnosis of fat embolism?

A) True

B) False

Answer: B

Although fat embolism is defined as the presence of fat globules in pulmonary circulation, absence of fat does not rule out the diagnosis. This question emphasizes that fat embolism syndrome (FES) is still a clinical diagnosis, depending on history and clinical signs. Although classic practice advocates swan-ganz catheter (PAC) floating, it is neither sensitive nor specific for FES. Floatation of a swan exclusively to rule out FES is not very prudent.

#pulmonary

Reference:

Gerald L Weinhouse: Fat embolism syndrome (FES): https://www.uptodate.com/contents/fat-embolism-syndrome © 2023 UpToDate, Inc. (last accessed June 24, 2023)

Uhthoff phenomenon

Q: Uhthoff phenomenon occurs in? (select one)

A) cold

B) heat


Answer: B

Transient flare-up of symptoms of  Multiple Sclerosis (MS) due to an increase in body temperature

Uhthoff phenomenon, named after a German ophthalmologist Wilhelm Uhthoff, is a transient (usually less than 24 hours) worsening of neurological function among MS patients in response to increases in core body temperature. This is distinct from the true relapse or exacerbation of MS. It does not require pulse corticosteroid or plasma exchange therapy. This is also called Uhthoff sign or Uhthoff syndrome. Precipitating factors include perimenstrual period, exercise, fever, hot baths, psychological stress, a hot meal, and smoking.

It has been described in all demyelinating disorders as well as other neuropathies. Nystagmus and other visual disorders are particularly prone to worsen in patients with MS after increased body temperature. Prophylactic 4-aminopyridine may help to reduce sensitivity to visual impairments. The mechanism of action is the temperature-sensitive conduction blockade of partially demyelinated axons in the demyelinated plaques.

Treatment is rest and a cooler environment.


#neurology 


References:

1. Opara JA, Brola W, Wylegala AA, Wylegala E. Uhthoff`s phenomenon 125 years later - what do we know today? J Med Life. 2016 Jan-Mar;9(1):101-105. 

2. Perkin GD, Rose FC. Uhthoff's syndrome. Br J Ophthalmol. 1976 Jan;60(1):60-3. 

3. Frohman TC, Davis SL, Beh S, Greenberg BM, Remington G, Frohman EM. Uhthoff's phenomena in MS--clinical features and pathophysiology. Nat Rev Neurol. 2013 Sep;9(9):535-40. 

4. van Diemen HA, van Dongen MM, Dammers JW, Polman CH. Increased visual impairment after exercise (Uhthoff's phenomenon) in multiple sclerosis: therapeutic possibilities. Eur. Neurol. 1992;32(4):231-4. 

IV and PO Vitamin K

Q: Oral Vitamin K has similar efficacy as intravenous (IV).

A) True

B) False

Answer: A

Some Pearls of Vitamin K (phytonadione)

• Oral Vitamin K has similar efficacy as intravenous Vitamin K. 
• SQ (subcutaneous) Vitamin K's absorption is unreliable.
• IM (intramuscular) Vitamin K may promote intramuscular hemorrhage.
• IV (intravenous) Vitamin K is effective in 6 - 8 hours.
• IV Vitamin K should be given very slowly (preferably .5 mg/min).
• IV Vitamin K may cause facial flushing, diaphoresis, chest pain, hypotension, dyspnea, anaphylaxis, and cerebral thrombosis but pretreatment with antihistamines or corticosteroids is not routinely recommended. 
• Although IV Vitamin K has been described as safe in a few studies, it should be used only in life-threatening bleeds from warfarin overdose or due to deficiency of vitamin K as fatality from anaphylactoid reaction could be high.

#hematology

#vitamins

References: 

1. Comparison of Oral vs Intravenous Phytonadione (Vitamin K) in Patients With Excessive Anticoagulation - Arch Intern Med. 2003;163:2469-2473.

 

2. Oral Vitamin K Lowers the International Normalized Ratio More Rapidly Than Subcutaneous Vitamin K in the Treatment of Warfarin-Associated Coagulopathy - Annals - 20 August 2002, Volume 137 Issue 4, Pages 251-254 

3. The safety of intravenously administered vitamin K - via pubmed, Vet Hum Toxicol. 2002 Jun;44(3):174-6.

4. Comparing Different Routes and Doses of Phytonadione for Reversing Excessive Anticoagulation - Arch Intern Med. 1998;158:2136-2140.

5. The incidence of anaphylaxis following intravenous phytonadione (vitamin K1): a 5-year retrospective review - Annals of Allergy, Asthma and Immunology, Volume 89, Number 4, October 2002, pp. 400-406(7)

Fentanyl patch and heat

Case: 62 years old male is transferred from the oncology floor with severe respiratory depression requiring intubation. A review of medical records didn't show any significant exposure to any pertinent drugs except the fentanyl dermal patch which he is using for the last few months without any side effects. Transferring team informed that prior to the event patient was feeling very cold and the nurse applied warm blankets.

Answer: Fentanyl dermal patch (trade name = Duragesic) is highly sensitive to heat exposure of any kind including heating pads, electric blankets, heat or tanning lamps, sunbathing, hot baths, saunas, hot tubs, and heated water beds. Heat increases fentanyl absorption and may result in fatal overdosing.

#toxicity

References:

1. Newshan G. Heat-related toxicity with the fentanyl transdermal patch. J Pain Symptom Manage. 1998 Nov;16(5):277-8. doi: 10.1016/s0885-3924(98)00100-6. PMID: 9846020.

2. Kriikku P, Ojanperä I, Lunetta P. Death in Sauna Associated With a Transdermal Fentanyl Patch. Am J Forensic Med Pathol. 2020 Dec;41(4):313-314. doi: 10.1097/PAF.0000000000000565. PMID: 32740103.

3. Hessulf F. Can't take the heat: sauna and Fentanyl patch intoxication. Clin Toxicol (Phila). 2019 Mar;57(3):219. doi: 10.1080/15563650.2018.1499932. Epub 2018 Aug 10. PMID: 30095280.

Behçet syndrome and genital aphthae

Q: Which of the following is required to establish the diagnosis of Behçet syndrome? 

A) genital aphthae

B) oral aphthae

Answer: B

Behçet syndrome, also called Behçet disease, has been known since Hippocrates times but is named after Hulusi Behçet. It is broadly defined as recurrent oral aphthae and any other systemic involvement, as Behçet syndrome involves blood vessels of all sizes (small, medium, and large). Also, it can affect either or both arterial and venous vessels. Although Behçet syndrome is mostly known for its genital involvement, it is not required to establish the diagnosis. It can cause genital aphthae, eye disease, dermal lesions, gastrointestinal involvement, neurologic disease, vascular disease, or even arthritis.

People living along the ancient silk road and Turkey is most affected for reasons not fully understood.

#vasculitis 

References:

1. Feigenbaum A. Description of Behçet's syndrome in the Hippocratic third book of endemic diseases. Br J Ophthalmol 1956; 40:355.

2. Behcet H. Uber rezidivierende, aphthose durch ein virus verursachte geschwure am mund, am auge und an der genitalen. Dermatologische Wochenschrift 1937; 105:1152.

3. Yurdakul S, Hamuryudan V, Yazici H. Behçet syndrome. Curr Opin Rheumatol 2004; 16:38.

Work up prior to TAVI

Q: 82 years old female is admitted to ICU with shortness of breath(SOB). Subsequent workup led to the diagnosis of Aortic Stenosis(AS). Plan is made to perform Transcatheter Aortic Valve Implantation (TAVI). The surgical team requests the ICU team to perform a preprocedural workup. Which of the following is considered a standard test before TAVI? (select one)

A) Multidetector computed tomography (MDCT) angiography

B) Cardiac magnetic resonance (CMR) 

Answer: A

In morbidly elder patients with critical or severe AS, TAVI is fastly becoming a procedure of choice. A few essential workups include echocardiography, mostly transthoracic (transesophageal per clinician's discretion), coronary angiogram, which may include aortography and peripheral angiography, and Multidetector computed tomography (MDCT).

MDCT angiography is now universally considered a standard as it provides essential information regarding aortic annulus and sinus dimensions, descending aorta, and iliofemoral vascular system. 

MDCT can be challenging in patients with renal dysfunction, dye allergy, arrhythmias, and pulmonary disease. In such cases, cardiac magnetic resonance (CMR) is a noninvasive modality and provides detailed visualization of cardiac structures and quantitative flow measurements.

#surgical-critical-care

References: 

1. Nishimura RA, Otto CM, Bonow RO, et al. 2014 AHA/ACC guideline for the management of patients with valvular heart disease: a report of the American College of Cardiology/American Heart Association Task Force on Practice Guidelines. J Am Coll Cardiol 2014; 63:e57.

2. Binder RK, Webb JG, Willson AB, et al. The impact of integration of a multidetector computed tomography annulus area sizing algorithm on outcomes of transcatheter aortic valve replacement: a prospective, multicenter, controlled trial. J Am Coll Cardiol 2013; 62:431.

3. Lopez-Mattei JC, Shah DJ. When to consider cardiovascular magnetic resonance in patients undergoing transcatheter aortic valve replacement? Curr Opin Cardiol 2013; 28:505.

False negative Guaiac stool

Q: 42 years old male with known history of esophageal varices is admitted to ICU with bloating, 'loin to groin,' and abdominal pain. Due to the associated history, GI bleed is suspected. Patient reported recent 'cold-like symptoms' and was consuming large doses of vitamins to improve his immunity. Bedside stool guaiac turns negative. Toxicity of which vitamin may give false-negative stool guaiac?

Answer: Vitamin C

Unfortunately, vitamin C is largely abused in the population. Mega doses of vitamin C can result in false-negative stool guaiac. Other symptoms are diarrhea, abdominal pain, and bloating. Moreover, it may give rise to oxalate kidney stones, particularly in males. There are some reports of association with fatal cardiac arrhythmias when mega doses of vitamin C and iron are taken together.

#toxicology

References:

1. Jaffe RM, Kasten B, Young DS, MacLowry JD. False-negative stool occult blood tests caused by ingestion of ascorbic acid (vitamin C). Ann Intern Med 1975; 83:824.

2. Ferraro PM, Curhan GC, Gambaro G, Taylor EN. Total, Dietary, and Supplemental Vitamin C Intake and Risk of Incident Kidney Stones. Am J Kidney Dis 2016; 67:400.

3. McLaran CJ, Bett JH, Nye JA, Halliday JW. Congestive cardiomyopathy and haemochromatosis--rapid progression possibly accelerated by excessive ingestion of ascorbic acid. Aust N Z J Med 1982; 12:187.

Morphine in acute MI

Q: Prophylactic use of morphine in acute myocardial infarction(MI) has a beneficial effect and should be used on all patients?

A) True

B) False

Answer: B

Morphine should be used in acute ST Elevation MI only when patient does not get relieved of chest pain from nitrates and oxygen, in case saturation is below 94%. Routine use of morphine should highly be discouraged for two reasons.

1. It may depress respiratory drive and there lies a danger of undue mechanical ventilation.

2. Morphine has shown to diminish the effect of P2Y12 inhibitors.

No data suggests that routine use of morphine reduces mortality.

#cardiology

References:

1. Meine TJ, Roe MT, Chen AY, et al. Association of intravenous morphine use and outcomes in acute coronary syndromes: results from the CRUSADE Quality Improvement Initiative. Am Heart J 2005; 149:1043.

2. Kubica J, Adamski P, Ostrowska M, et al. Morphine delays and attenuates ticagrelor exposure and action in patients with myocardial infarction: the randomized, double-blind, placebo-controlled IMPRESSION trial. Eur Heart J 2016; 37:245.

3. Hobl EL, Stimpfl T, Ebner J, et al. Morphine decreases clopidogrel concentrations and effects: a randomized, double-blind, placebo-controlled trial. J Am Coll Cardiol 2014; 63:630.

Causes of FUO

Q: Which of the following is the most common cause of Fever of Unknown Origin (FUO)? (select one)

A) Occult infections

B) Underlying connective tissue diseases

C) Occult malignancies

Answer: A

FUO has baffled clinicians for over many years. In modern medical literature, the first mention is as far as back to 1930.

Infections, most commonly tuberculosis (TB) is found to be the single most common infection in studies of most FUO series. This is followed by occult abscesses such as pyogenic liver abscesses, osteomyelitis and bacterial endocarditis.

Connective tissue diseases are second to infections. It includes adult-onset Still’s disease, and giant cell arteritis (GCA).

The most common malignancies for FUO lymphoma, especially non-Hodgkin's, leukemia, renal cell carcinoma and hepatocellular carcinoma or tumors metastatic to the liver.

Other causes of FUO are factitious fever, alcoholic hepatitis, thromboembolism, hematoma, hyperthyroidism, hereditary periodic fever syndromes and drugs.

#ID

References:

1. Alt HL, Barker MH. Fever of unknown origin. JAMA 1930; 94:1457.

2. PETERSDORF RG, BEESON PB. Fever of unexplained origin: report on 100 cases. Medicine (Baltimore) 1961; 40:1.

3. Popovska-Jovicić B, Canović P, Gajović O, Raković I, Mijailović Z. Fever of unknown origin: Most frequent causes in adults patients. Vojnosanit Pregl. 2016 Jan;73(1):21-5. doi: 10.2298/vsp140820128p. PMID: 26964380.

Wheezing in Asthma

Q: Presence of wheezing in exacerbation of asthma signifies its severity?

A) True

B) False

Answer: B

Although wheezing is considered a cardinal feature in asthma exacerbation, its presence or absence is a very poor predictor of the severity of airflow obstruction. It can be heard even in mild forms of asthma. Similarly, widespread airway narrowing can be present without any wheezing. 

#pulmonary

References:

1. Gong H JR.. Wheezing and Asthma. In: Walker HK, Hall WD, Hurst JW, editors. Clinical Methods: The History, Physical, and Laboratory Examinations. 3rd edition. Boston: Butterworths; 1990. Chapter 37. Available from: https://www.ncbi.nlm.nih.gov/books/NBK358/

2. Patel PH, Mirabile VS, Sharma S. Wheezing. 2023 May 1. In: StatPearls [Internet]. Treasure Island (FL): StatPearls Publishing; 2023 Jan–. PMID: 29494061.

3. Chou EY, Pelz BJ, Chiu AM, Soung PJ. All that Wheezes is not Asthma or Bronchiolitis. Crit Care Clin. 2022 Apr;38(2):213-229. doi: 10.1016/j.ccc.2021.11.002. PMID: 35369944.

Anesthesia in orthopedic surgery and DVT

Q; Patients undergoing General Anesthesia during orthopedic surgery have a higher risk of thromboembolism than patients undergoing spinal anesthesia?

A) True

B) False

Answer: A

Overall orthopedic procedures have a higher risk of thromboembolism. Some patients carry extra risk due to other underlying factors. Some of these factors are:

• Greater extent of surgery
• Longer duration of surgery
• General anesthesia 
• Prolonged immobilization postoperatively
• Prolonged casting postoperatively
• Bilateral total joint arthroplasty 
• Age >75 years 
• Obesity
• Cardiovascular disease
• Compression of the deep veins from the positioning of the extremity during hip surgery
• Use of a thigh tourniquet during knee surgery

#surgical-critical-care

References:

1. White RH, Zhou H, Romano PS. Incidence of symptomatic venous thromboembolism after different elective or urgent surgical procedures. Thromb Haemost 2003; 90:446.

2. Leizorovicz A, Turpie AG, Cohen AT, et al. Epidemiology of venous thromboembolism in Asian patients undergoing major orthopedic surgery without thromboprophylaxis. The SMART study. J Thromb Haemost 2005; 3:28.

3. Mantilla CB, Horlocker TT, Schroeder DR, et al. Risk factors for clinically relevant pulmonary embolism and deep venous thrombosis in patients undergoing primary hip or knee arthroplasty. Anesthesiology 2003; 99:552.

BB and triglycerides

Q: Most beta-blockers modestly _____________ the triglycerides? (select one)

A) decreases

B) increases

Answer: B

Beta-blockers (BB) have independent effects on serum lipids. 

Most BB, including atenolol, metoprolol, and propranolol, increases the triglycerides by 20-40 percent. Also, they decrease the HDL by 10 percent, though overall, there is little effect on total cholesterol or LDL. This effect is more pronounced in smokers.

BB with alpha effects, such as labetalol and carvedilol, has less effect on triglycerides. Nebivolol is one unique cardioselective beta 1 adrenergic receptor blocker with a neutral effect.

Overall, BB has a beneficial effect due to its safe and strong anti-hypertensive properties, and it should not hold clinicians back from using it along with statins.

#pharmacology

References:

1. Kasiske BL, Ma JZ, Kalil RS, Louis TA. Effects of antihypertensive therapy on serum lipids. Ann Intern Med 1995; 122:133.

2. Vyssoulis GP, Karpanou EA, Pitsavos CE, et al. Dyslipidemic effects of cigarette smoking on beta-blocker-induced serum lipid changes in systemic hypertension. Am J Cardiol 1991; 67:987.

3. Wolinsky H. The effects of beta-adrenergic blocking agents on blood lipid levels. Clin Cardiol 1987; 10:561.

location of neural foramina

Q: Each neural foramina lies just ____________ the same number of  vertebral body? (select one)

A) above

B) below

Answer: B

The lumbosacral spine consists of 11 structures, i.e., 5 lumbar vertebrae (L1-L5), 5 sacral vertebrae (S1-S5), and a terminal bony prominence called the coccyx. Directly beneath each vertebra lies a pair of neural foramina. For example, L1 neural foramina are located below the L1 vertebral body. Each neural foramen passes the same numbered spinal nerve root, recurrent meningeal nerves, and radicular blood vessels.

References:

1. Hay MC. Anatomy of the lumbar spine. Med J Aust 1976; 1:874.

2. Hashmi SS, Seifert KD, Massoud TF. Thoracic and Lumbosacral Spine Anatomy. Neuroimaging Clin N Am. 2022 Nov;32(4):889-902. doi: 10.1016/j.nic.2022.07.024. PMID: 36244729.

Cancer after solid organ transplant

Q: 54 years old male with a previous history of  kidney transplant twice, is admitted to ICU with sepsis and enlarged lymph nodes. On clinical exam also found to have scaly, erythematous nodules on his skin. Which is the most common cancer in solid organ transplant recipients? (select one)

A) Lymphoma

B) Skin cancer

Answer: B

Cutaneous malignancy is the most common malignancy post solid organ transplant, counting for almost 40% of all cancers in solid organ transplants. The most common are cutaneous squamous cell carcinoma and basal cell carcinoma. The most common risk factors are

• intensity of immunosuppression
• duration of immunosuppression
• ethnicity (in 50% of white or fair skin vs. only 6% on dark skin)
• sun exposure 
• geographic location

#oncology

References:

1. Euvrard S, Kanitakis J, Claudy A. Skin cancers after organ transplantation. N Engl J Med 2003; 348:1681.

2. Chung CL, Nadhan KS, Shaver CM, et al. Comparison of Posttransplant Dermatologic Diseases by Race. JAMA Dermatol 2017; 153:552.

3. Garrett GL, Blanc PD, Boscardin J, et al. Incidence of and Risk Factors for Skin Cancer in Organ Transplant Recipients in the United States. JAMA Dermatol 2017; 153:296.

Tracheomalacia

Q: Tracheomalacia (TM) causes airway narrowing during? (select one)

A) expiration

B) inspiration

Answer: A

Tracheomalacia (TM) is a generalized term for expiratory central airway collapse (ECAC). It can be purely TM, bronchomalacia (BM), tracheobronchomalacia (TBM), or excessive (or expiratory) dynamic airway collapse of the posterior membrane (EDAC).

Treatment is mostly conservative with breathing techniques and pulmonary rehabilitation, but in persistent cases, it may require stent - and, in severe cases, surgery.

#pulmonary

References:

1. Yang D, Cascella M. Tracheomalacia. 2022 Jul 9. In: StatPearls [Internet]. Treasure Island (FL): StatPearls Publishing; 2023 Jan–. PMID: 31985984.

2. Kugler C, Stanzel F. Tracheomalacia. Thorac Surg Clin. 2014 Feb;24(1):51-58. doi: 10.1016/j.thorsurg.2013.09.003. PMID: 24295659.

CXR in MERS-CoV

Q: In the Middle East Respiratory Syndrome CoronaVirus (MERS-CoV), chest X-ray tends to be abnormal in almost 100% of the cases?

A) True

B) False

Answer: A

In contrast to the COVID-19 virus, MERS-CoV is usually more severe if contracted. The chances of going on a ventilator are more than 70%. 

Available epidemiology till date, all the patients have abnormal CXR, which can range from minimal to marked. Findings have no described pattern, which can be anything -  from increased bronchial markings, opacities, and infiltrates to pleural effusions. A CT scan usually shows ground-glass opacity in a peripheral location.

#pulmonary

#ID

References:

1. Assiri A, Al-Tawfiq JA, Al-Rabeeah AA, et al. Epidemiological, demographic, and clinical characteristics of 47 cases of Middle East respiratory syndrome coronavirus disease from Saudi Arabia: a descriptive study. Lancet Infect Dis 2013; 13:752.

2. Das KM, Lee EY, Al Jawder SE, et al. Acute Middle East Respiratory Syndrome Coronavirus: Temporal Lung Changes Observed on the Chest Radiographs of 55 Patients. AJR Am J Roentgenol 2015; 205:W267.

3. Ajlan AM, Ahyad RA, Jamjoom LG, et al. Middle East respiratory syndrome coronavirus (MERS-CoV) infection: chest CT findings. AJR Am J Roentgenol 2014; 203:782.

4. Das KM, Lee EY, Langer RD, Larsson SG. Middle East Respiratory Syndrome Coronavirus: What Does a Radiologist Need to Know? AJR Am J Roentgenol 2016; 206:1193.

Increased QRS and LBBB in CHF

Q: QRS prolongation is associated with increased mortality in heart failure patients?

A) True

B) False

Answer: A

A QRS duration ≥120 ms is highly associated with increased all-cause mortality in congestive heart failure (CHF) patients. QRS prolongation leads to conduction defect and ventricular dyssynchrony. Similarly, one-fourth of these patients have Left bundle branch block (LBBB) and is also associated with increased all-cause mortality and sudden cardiac death. LBBB is also considered a marker even if not a direct cause of increased mortality risk. 

Clinical implication: Cardiac resynchronization with biventricular pacing should highly be considered.

#cardiology

References:

1. Wang NC, Maggioni AP, Konstam MA, et al. Clinical implications of QRS duration in patients hospitalized with worsening heart failure and reduced left ventricular ejection fraction. JAMA 2008; 299:2656.

2. Baldasseroni S, Opasich C, Gorini M, et al. Left bundle-branch block is associated with increased 1-year sudden and total mortality rate in 5517 outpatients with congestive heart failure: a report from the Italian network on congestive heart failure. Am Heart J 2002; 143:398.

3. Tabrizi F, Englund A, Rosenqvist M, et al. Influence of left bundle branch block on long-term mortality in a population with heart failure. Eur Heart J 2007; 28:2449.

pqrstu of CXR

Q: What is the "pqrstu" of the chest-x-ray (CXR)?

Answer: Few people know that like the famous 'pqrs' of EKG, CXR also has a 'pqrsu' classification though now mostly of academic interest since CT scans become a norm. This classification is based on shape and size:

p - Round/nodular opacity - up to 1.5 mm

q - Round/nodular opacity - 1.5-3 mm

r - Round/nodular opacity - 3-10 mm

s - Irregular/linear/reticular opacity - up to 1.5 mm

t - Irregular/linear/reticular opacity - 1.5 to 3 mm

u - Irregular/linear/reticular opacity - 3 to 10 cm

#radiology

#pulmonary

Reference;

1. Paul stark - Evaluation of diffuse lung disease by conventional chest radiography - @©UpToDate - https://www.uptodate.com/contents/evaluation-of-diffuse-lung-disease-by-conventional-chest-radiography

2. Russell, A (Ed). International Labour Office: Guidelines for the Use of ILO International Classification of Radiographs of Pneumoconioses. Revised Edition 1980. Medical Radiography and Photography 1981; 1:2.

Synthetic cannabis

Q: Five college students are brought to ER after a dorm's 'crazy monkey' party with multiple symptoms including tachycardia, psychosis and slurred speech. Rapid urine drug screen is negative for cannabinoids for all patients. What is your probable diagnosis?

Answer: Synthetic cannabinoid toxicity

Unfortunately synthetic cannabinoid (a misnomer) is a widely available and abused drug during parties. Various street names are K2, spice, crazy monkey, chill out, spice diamond, spice gold, and chill X. Rapid urine drug screens can not detect synthetic cannabinoids. It requires time consuming liquid chromatography and mass spectrometry tests.

There is no antidote and management is symptomatic treatment for tachycardia, hyperthermia, rhabdomyolysis, chest pain, pneumothorax, stroke or kidney failure. Benzodiazepines may be helpful.

#toxicology

References:

1. Kuehn B. Synthetic Cannabidiol Poisoning. JAMA 2018; 319:2264.

2. Mills B, Yepes A, Nugent K. Synthetic Cannabinoids. Am J Med Sci. 2015 Jul;350(1):59-62. doi: 10.1097/MAJ.0000000000000466. PMID: 26132518.

3. Darke S, Banister S, Farrell M, Duflou J, Lappin J. 'Synthetic cannabis': A dangerous misnomer. Int J Drug Policy. 2021 Dec;98:103396. doi: 10.1016/j.drugpo.2021.103396. Epub 2021 Jul 31. PMID: 34343944.

Diagnostic clues in viral encephalitis

Q: Tremors of the eyelids, tongue, lips, and extremities suggest which encephalitis? (select one)

A) St. Louis encephalitis

B) mumps encephalitis 

C) encephalitic rabies

D) varicella-zoster virus (VZV) encephalitis

Answer: A

The objective of this question is to emphasize the important diagnostic clues in the differential diagnosis of suspected viral encephalitis. A few major specific findings of different viral encephalitis are:

• Parotitis - mumps encephalitis
• Flaccid paralysis, a polio-like presentation - West Nile virus infection (frequently misdiagnosed as Guillain-Barré syndrome). A maculopapular rash with the above symptom almost confirms the West Nile virus.
• Tremors of the eyelids, tongue, lips, and extremities - St. Louis encephalitis or West Nile encephalitis (geographic location of known epidemiology is a major determinant.)
• Hydrophobia, aerophobia, pharyngeal spasms, and hyperactivity - encephalitic rabies. It may also present as seizures, cranial nerve palsies, and myoclonus.
• Grouped vesicles in a dermatomal pattern - varicella-zoster virus (VZV).

#neurology

#ID

References:

1. Steiner I, Budka H, Chaudhuri A, Koskiniemi M, Sainio K, Salonen O, Kennedy PG. Viral encephalitis: a review of diagnostic methods and guidelines for management. Eur J Neurol. 2005 May;12(5):331-43. doi: 10.1111/j.1468-1331.2005.01126.x. PMID: 15804262.

2. Esang M, Goldstein S, Dhami R. The Role of Physical Examinations in Psychiatry as Illustrated in a Case of Neuroleptic Malignant Syndrome Versus Viral Encephalitis: A Case Report and Literature Review. Cureus. 2019 Jun 5;11(6):e4840. doi: 10.7759/cureus.4840. PMID: 31410323; PMCID: PMC6684120.

3. Stephen J Gluckman - https://www.uptodate.com/contents/viral-encephalitis-in-adults - © 2023 UpToDate, Inc

non-septic vasoplegia

Q; Name at least 7 non-septic conditions which can cause low SVR (systemic vascular resistance)?

Answer: Low SVR (vasoplegia) can be fatal. Also, it can take a lot of work to manage despite IVF and pressors.  A few non-infectious causes of low SVR are below:

1. Hemorrhagic (or necrotizing) Pancreatitis

2. Cirrhosis

3. Adrenal insufficiency

4. Head Injury ( initially increased SVR followed by low SVR)

5. Bactrim (TMP-SMX) in AIDS patient

6. Within 6 hours of post cardiopulmonary bypass 

7. Spinal cord Injury above T6 (inhibited vagal tone)

#hemodynamic

Further reading:

1. Lambden S, Creagh-Brown BC, Hunt J, Summers C, Forni LG. Definitions and pathophysiology of vasoplegic shock. Crit Care. 2018 Jul 6;22(1):174. doi: 10.1186/s13054-018-2102-1. PMID: 29980217; PMCID: PMC6035427.

2. Levy B, Fritz C, Tahon E, Jacquot A, Auchet T, Kimmoun A. Vasoplegia treatments: the past, the present, and the future. Crit Care. 2018 Feb 27;22(1):52. doi: 10.1186/s13054-018-1967-3. PMID: 29486781; PMCID: PMC6389278.

IABP during code

Q: 58 years old male with cardiogenic shock and on intra aortic balloon pump (IABP), became pulseless in ICU. 'Code' is called, and CPR is started. IABP should preferably be on? (select one)

A) "standby" mode

B) "ECG trigger" mode

C) "Pressure trigger" mode

D) immediately withdraw/discontinue

Answer: C

If a patient on IABP requires CPR, it should not be discontinued (choice D). It should be switched to "pressure trigger" (choice C). IABP is usually on "ECG trigger" by default to synchronize with the systole and diastole of the heart. 

IABP during CPR is actually helpful. It improves cerebral and cardiac blood flow. 

With CPR, on "pressure trigger," an arterial pressure tracing should be generated on the console/screen. If the console is not recognizing the arterial pressure tracing, chest compressions may not be adequate. 

If the bedside staff needs clarification or is uncomfortable regarding IABP during code, it can be switched to 'standby' mode (choice A), but it is not a recommended setting.

#procedures

#devices

#cardiology

Further reading:

1. Unverzagt S, Buerke M, de Waha A, Haerting J, Pietzner D, Seyfarth M, Thiele H, Werdan K, Zeymer U, Prondzinsky R. Intra-aortic balloon pump counterpulsation (IABP) for myocardial infarction complicated by cardiogenic shock. Cochrane Database Syst Rev. 2015 Mar 27;2015(3):CD007398. doi: 10.1002/14651858.CD007398.pub3. PMID: 25812932; PMCID: PMC8454261.

2. Buckley AJ, O'Connor C, Fitzgerald S, Hennessy T, Kiernan T. Mechanical Chest Compressions and Intra-Aortic Balloon Pump Combination for Refractory Ventricular Fibrillation During Primary PCI. JACC Case Rep. 2022 Mar 16;4(6):364-369. doi: 10.1016/j.jaccas.2022.01.018. PMID: 35495556; PMCID: PMC9040123.

3. Osborn C, Quaal SJ. Maximizing cardiopulmonary resuscitation in patients with intra-aortic balloon pumps. Crit Care Nurse. 1998 Apr;18(2):25-7. PMID: 9708117.

Seasonal K disturbunce

Case: 34 years old otherwise healthy male received a call from his Primary Care Physician (PCP) office in Houston, Texas, to go to Emergency Room (ER) due to severe potassium level disturbance reported from his well-check labs last week. PCP is out on summer vacation. The repeat potassium level at ER was reported at the lower limit of the reference range. Three more patients presented to ER due to similar phone calls from their PCP offices. Probable cause is? (Select one)

A) Seasonal pseudohyperkalemia

B) Seasonal pseudohypokalemia 

Answer: B

One interesting phenomenon which is less recognized is the occurrence of seasonal hypokalemia in the population during the summer months. This phenomenon is mostly reported from blood samples collected on out-patient during summer months. If the sample is not stored or transported per guidelines results in a reversible in vitro phenomenon mediated by sodium-potassium-exchanging-ATPase due to increased temperature. Still needs to fully explain why many of these patients on repeated labs in a hospital setting have their potassium at the lower limit of the reference range, though the same mechanism, i.e., mediation by sodium-potassium-exchanging-ATPase is suspected.

#electrolytes

#lab-medicine

Reference:

Sodi R, Davison AS, Holmes E, Hine TJ, Roberts NB. The phenomenon of seasonal pseudohypokalemia: effects of ambient temperature, plasma glucose and role for sodium-potassium-exchanging-ATPase. Clin Biochem. 2009 Jun;42(9):813-8. doi: 10.1016/j.clinbiochem.2009.01.024. Epub 2009 Feb 14. PMID: 19232334.

Uremic bleeding

Q: Out of the following, which treatment would NOT work in active bleeding from Uremia?

A) Desmopressin (DDAVP)

B) Hemodialysis

C) IV Estrogen

D) PO Estrogen

E) Cryoprecipitate

Answer:  B

Paradoxically, dialysis is very effective in preventing uremic bleeding but has no role in active bleeding from uremia. DDAVP is the most potent remedy in such situations, followed by cryoprecipitate. Estrogen (IV or PO) has also shown some effectiveness.

#nephrology

#hematology

Reference:

Hedges, S., Dehoney, S., Hooper, J. et al. Evidence-based treatment recommendations for uremic bleeding. Nat Rev Nephrol 3, 138–153 (2007). https://doi.org/10.1038/ncpneph0421

SS

Q: Serotonin syndrome (SS) is caused by overstimulation of? (select one)

A) central serotonin receptors

B) peripheral serotonin receptors

C) central and peripheral serotonin receptors

Answer: C

The conventional belief is that SS occurs due to central serotonin receptors. It is partially true. SS occurs due to both overstimulation of central and peripheral serotonin receptors. Mild cases of SS may go unnoticed as they may involve only nausea, vomiting, flushing, and diaphoresis. Severe cases cause hyperreflexia, myoclonus, muscular rigidity, hyperthermia, and autonomic instability. Myoclonus, tachycardia, and hyperthermia may be the most important clues as the diagnosis of SS is clinical and no lab tests are available.

Treatment includes discontinuation of all serotonergic medications. The initial treatment of serotonin syndrome is with benzodiazepines and cyproheptadine. Cyproheptadine (Periactin) appears to be the most effective antiserotonergic agent in humans. 

#pharmacology

#neurology

References:

1. Scotton WJ, Hill LJ, Williams AC, Barnes NM. Serotonin Syndrome: Pathophysiology, Clinical Features, Management, and Potential Future Directions. Int J Tryptophan Res. 2019 Sep 9;12:1178646919873925. doi: 10.1177/1178646919873925. PMID: 31523132; PMCID: PMC6734608.

2. Werneke U, Truedson-Martiniussen P, Wikström H, Ott M. Serotonin syndrome: a clinical review of current controversies. J Integr Neurosci. 2020 Dec 30;19(4):719-727. doi: 10.31083/j.jin.2020.04.314. PMID: 33378846.

On Moyamoya and its treatment

Moyamoya disease is a progressive cerebrovascular disease in which certain arteries in the brain are constricted, causing a stroke. Collateral circulation develops around the blocked vessels to compensate for the blockage, but the collateral vessels are small, weak, and prone to hemorrhage, aneurysm, and thrombosis. Radiologically, these collateral vessels appear as a "puff of smoke." The name “moyamoya” means “puff of smoke” in Japanese.

Medically aspirin is usually prescribed, but permanent treatment is surgical. 

#neurology

References:

1. Gupta A, Tyagi A, Romo M, Amoroso KC, Sonia F. Moyamoya Disease: A Review of Current Literature. Cureus. 2020 Aug 30;12(8):e10141. doi: 10.7759/cureus.10141. PMID: 33014640; PMCID: PMC7526970.

2. Berry JA, Cortez V, Toor H, Saini H, Siddiqi J. Moyamoya: An Update and Review. Cureus. 2020 Oct 16;12(10):e10994. doi: 10.7759/cureus.10994. PMID: 33209550; PMCID: PMC7667711.

Tension Gastrothorax

Q: What is Tension Gastrothorax?

Answer: Patients with self-ventilating diaphragmatic injury or defect (negative pressure ventilation) may sometimes have abdominal content, mostly stomach to herniate (pull) in the chest. It may appear as pneumothorax on CXR due to distended trap air. It occurs in children due to congenital diaphragmatic injury, and in adults, it occurs after trauma.

It can be fatal. Acute management includes placing a Nasogastric(NG) tube or positive pressure ventilation. Also, needle decompression has been described.

#trauma

References:

1. Horst M, Sacher P, Molz G, Willi UV, Meuli M. Tension gastrothorax. J Pediatr Surg. 2005 Sep;40(9):1500-4. doi: 10.1016/j.jpedsurg.2005.05.079. PMID: 16150360. 

2. Næss PA, Wiborg J, Kjellevold K, Gaarder C. Tension gastrothorax: acute life-threatening manifestation of late onset congenital diaphragmatic hernia (CDH) in children. Scand J Trauma Resusc Emerg Med. 2015 Jun 24;23:49. doi: 10.1186/s13049-015-0129-8. PMID: 26104782; PMCID: PMC4477604.

3. Miyahara M, Kondo N, Sugiyama T, Matsumura Y. Resuscitation from Cardiac Arrest with Tension Gastrothorax Due to Acquired Diaphragmatic Hernia. Am J Emerg Med. 2022 Oct;60:229.e1-229.e3. doi: 10.1016/j.ajem.2022.07.054. Epub 2022 Jul 31. PMID: 35961833.

ETT exchange

Q: Endotracheal tube (ETT) introducer, popularly known as a bougie, can be safely used to exchange malfunctioning ETT?

A) True

B) False

Answer: B

Bougie is not designed to exchange malfunctioning ETT. Its main purpose is to facilitate presumed difficult intubations and should be use as an introducer during such intubations. Using a bougie as an ETT exchanger risks the loss of airway as a standard bougie is usually 60 to 70 cm long and barely allows the full length of the ETT to leave the mouth. 

The standard (and proper) ETT exchangers are usually 80 cm long, are designed solely for this purpose, and can be use without risking the loss of airway.

#procedures

Further read:

1. Heidegger T, Oberle F. Endotracheal Tube Exchange. N Engl J Med. 2023 Mar 16;388(11):e34. doi: 10.1056/NEJMvcm2020253. PMID: 36920758.

2. Hartmannsgruber MW, Rosenbaum SH. Safer endotracheal tube exchange technique. Anesthesiology. 1998 Jun;88(6):1683. doi: 10.1097/00000542-199806000-00038. PMID: 9637668.

HIV drugs resistance assay

Q: Which are the two fundamental types of HIV drug resistance assay?

Answer: GENOTYPIC and PHENOTYPIC

As medical science is fast integrating precision medicine, drug therapy is fast getting based on resistance assay for each patient. Studies have shown that proper resistance assay improves management as well as survival. There are two major types of assays in this regard:

1. Genotypic: It provides information regarding specific drug resistance mutations in the regions of the HIV genome encoding protease, reverse transcriptase, and integrase. Results are reported as individual mutations. It reports each antiretroviral drug as

• susceptible
• possibly resistant, or
• resistant

2. Phenotypic: This principle is similar to bacteriologic methods, providing an inhibitory concentration required to inhibit in vitro growth by 50 percent (IC50) compared with virus replication without a drug. It aggregates the acquired drug mutations in a patient's viral strain. This is reported as a fold-change in drug susceptibility of the patient sample compared with a laboratory reference strain without resistance.

#ID

#pharmacology

References: 

1. Günthard HF, Calvez V, Paredes R, Pillay D, Shafer RW, Wensing AM, Jacobsen DM, Richman DD. Human Immunodeficiency Virus Drug Resistance: 2018 Recommendations of the International Antiviral Society-USA Panel. Clin Infect Dis. 2019 Jan 7;68(2):177-187. doi: 10.1093/cid/ciy463. PMID: 30052811; PMCID: PMC6321850.

2. Van Vaerenbergh K. Study of the impact of HIV genotypic drug resistance testing on therapy efficacy. Verh K Acad Geneeskd Belg. 2001;63(5):447-73. PMID: 11813503.