Erythromycin and gastroparesis

Q: Erythromycin improves gastrointestinal motility by mostly acting at? (select one)

A) Gastric fundus

B) Duodenum

C) Jejunum

D) Descending colon

Answer: A

Although not as popular as previously, many clinicians continue to utilize Erythromycin for gastroparesis in inpatient settings. Erythromycin is a motilin agonist and induces high-amplitude gastric propulsive contractions. Erythromycin usually stimulates fundic contractility that inhibits the accommodation response of the proximal stomach after food ingestion. 

Gastroparesis effect can be evident even at very small doses at 40 mg. Erythromycin should not be used more than 250 mg three times daily due to potential side effects. Patients who are not on continuous tube feed in the ICU should be given erythromycin before meals. 

Intravenous Erythromycin is said to be more effective than oral administration.

Potential issues with erythromycin are tachyphylaxis, abdominal pain, ototoxicity (long-term use), bacterial resistance, QT prolongation, and sudden death.

Another utility of erythromycin is to accelerate the transpyloric migration of the tip of an enteral feeding tube, a common issue in ICU.

#nutrition

#pharmacology

#GI

References:

1. Keshavarzian A, Isaac RM. Erythromycin accelerates gastric emptying of indigestible solids and transpyloric migration of the tip of an enteral feeding tube in fasting and fed states. Am J Gastroenterol 1993; 88:193.

2. Bruley des Varannes S, Parys V, Ropert A, et al. Erythromycin enhances fasting and postprandial proximal gastric tone in humans. Gastroenterology 1995; 109:32.

3. Maganti K, Onyemere K, Jones MP. Oral erythromycin and symptomatic relief of gastroparesis: a systematic review. Am J Gastroenterol 2003; 98:259.

Poncet Disease

Q: Poncet disease by definition is? (select one)

A) an infectious disease

B) an inflammatory disease

Answer: B

Poncet disease is characterized by four conditions 

• acute
• symmetric
• polyarthritic (small and large joints)
• associated with active TB

Although it is associated with active extrapulmonary, pulmonary, or miliary TB, it is an inflammatory response without any objective evidence of active TB. The probable cause is immune-mediated. HIV is considered to be a risk factor.

It resolves within a few weeks of initiation of anti-TB therapy. Fortunately, it does not leave any residual joint destruction.

#ID

#rheumatology

References:

1. Isaacs AJ, Sturrock RD. Poncet's disease--fact or fiction? A re-appraisal of tuberculous rheumatism. Tubercle 1974; 55:135.

Sood R, Wali JP, Handa R. Poncet's disease in a north Indian hospital. Trop Doct 1999; 29:33.

2. Arora S, Prakash TV, Carey RA, Hansdak SG. Poncet's disease: unusual presentation of a common disease. Lancet 2016; 387:617.

3. Kawsar M, D'Cruz D, Nathan M, Murphy M. Poncet's disease in a patient with AIDS. Rheumatology (Oxford) 2001; 40:346.

4. Kroot EJ, Hazes JM, Colin EM, Dolhain RJ. Poncet's disease: reactive arthritis accompanying tuberculosis. Two case reports and a review of the literature. Rheumatology (Oxford) 2007; 46:484.

SGLT2 and DKA Hx

Q:  Sodium-glucose cotransporter 2 (SGLT2) inhibitors should not be used in patients with a prior history of diabetic ketoacidosis (DKA)?

A) True

B) False

Answer: A

The objective of this question is to enhance the wave of "euglycemic DKA" witnessed in ICUs in the last couple of years. SGLT2 inhibitors should be used with great caution in patients with Type 2 diabetes with eGFR <45 mL/min/1.73 m2, and a prior history of  DKA.

As the Sodium-glucose cotransporter 2 inhibitors mechanism of action is via kidney, it may cause some degree of dehydration. It should also be used with caution in patients who are using nonsteroidal anti-inflammatory drugs (NSAIDs), angiotensin-converting enzyme (ACE) inhibitors/angiotensin II receptor blockers (ARBs), and diuretics. The combined therapy may predispose a patient to Acute Kidney Injury (AKI).

Three other major side effects are

• genitourinary tract bacterial and yeast infections
• bone loss and fracture
• lower extremity infection and amputation, particularly in patients with foot ulceration, neuropathy, foot deformity, and vascular disease

#endocrinology

#nephrology

#pharmacology

References:

1. Halimi S, Vergès B. Adverse effects and safety of SGLT-2 inhibitors. Diabetes Metab. 2014 Dec;40(6 Suppl 1):S28-34. doi: 10.1016/S1262-3636(14)72693-X. PMID: 25554069.

2. Singh M, Kumar A. Risks Associated with SGLT2 Inhibitors: An Overview. Curr Drug Saf. 2018;13(2):84-91. doi: 10.2174/1574886313666180226103408. PMID: 29485006.

3. Pittampalli S, Upadyayula S, Mekala HM, Lippmann S. Risks vs Benefits for SGLT2 Inhibitor Medications. Fed Pract. 2018 Jul;35(7):45-48. PMID: 30766374; PMCID: PMC6368009.

clinical subtypes of Multiple Sclerosis (MS)

Q: What are the three clinical subtypes of Multiple Sclerosis (MS) in adult patients?

Answer: MS is largely categorized into three clinical subtypes depending on behavior over the years, such as flares/exacerbations with full or incomplete recovery, fever, time period, progression, disability, plateaus, temporary minor improvements, and/or superimposed acute relapses.

1. Relapsing-remitting multiple sclerosis (RRMS)

2. Secondary progressive multiple sclerosis (SPMS)

3. Primary progressive multiple sclerosis (PPMS)

RRMS is defined as relapses with either full recovery or with sequelae and residual deficit upon recovery. There is no or minimal disease progression during the periods between disease relapses, though individual relapses themselves may occasionally result in severe residual disability.

SPMS evolves from RRMS; hence, the word "secondary" is used, as over time, the disease enters a stage of steady deterioration in function, with or without superimposed attacks. The relapse rate is typically reduced when the secondary progressive stage is reached. This may be a phenomenon of immunosenescence, as relapses and new MS lesions are less common as people age.

PPMS represents approximately 10 percent of MS cases and is characterized by disease progression from onset, although occasional plateaus, temporary minor improvements, and acute relapses may occur.

The treatment plans are differentiated depending on clinical subtypes.

Some authors mention a fourth type, as the name explains: clinically isolated syndrome (CIS)

#neurology

References:

1. Ghasemi N, Razavi S, Nikzad E. Multiple Sclerosis: Pathogenesis, Symptoms, Diagnoses and Cell-Based Therapy. Cell J. 2017 Apr-Jun;19(1):1-10. doi: 10.22074/cellj.2016.4867. Epub 2016 Dec 21. PMID: 28367411; PMCID: PMC5241505.

2. Fujihara K. [Clinical subtypes of multiple sclerosis and the immuno-pathogeneses]. Nihon Rinsho. 2003 Aug;61(8):1293-9. Japanese. PMID: 12962014.

"pseudos" of thrombocytosis

Q: Name at least three "pseudo" abnormalities in the lab that may occur due to thrombocytosis? 

Answer: Thrombocytosis in serum can cause other lab abnormalities, and may deceive clinicians as these are mostly pseudo conditions. The most well-known are

• Pseudo-hyperkalemia
• Pseudo-hyperphosphatemia
• Pseudo-hyper-acid phosphatase
• Pseudo-hypoxemia (even on ABG)

#lab-medicine

#electrolytes

#hematology

References:

1. Pseudo-hyperkalemia and thrombocytosis - Ann Biol Clin (Paris). 2003 Nov-Dec;61(6):696-8

2. The effect of thrombocytosis on serum potassium and phosphorus concentrations - The American journal of the medical sciences 1994, vol. 307, n 4, pp. 255-258 (19 ref.) - If pop-up is block, cut and paste in browser, http://cat.inist.fr/?aModele=afficheN&cpsidt=4062835

3. Platelet-derived acid phosphatase isoenzyme in the serum in thrombocythemia - Am J Clin Pathol.1977 Feb;67(2):177-9

4. Platelet larceny: spurious hypoxaemia due to extreme thrombocytosis - Eur Respir J 2008; 31:469-472

Acute hypocalcemia

Q: All of the following are the signs of acute hypocalcemia EXCEPT? (select one)

A) tetany

B) papilledema

C) seizures 

D) basal ganglia calcification

Answer: D

Patients with hypoparathyroidism usually develop signs of chronicity like ectodermal and dental changes, cataracts, basal ganglia calcification, and extrapyramidal disorders. All these signs take years to develop.

In contrast, people who develop acute hypocalcemia have:

Tetany — It occurs due to increased peripheral neuromuscular irritability with perioral numbness, paresthesias of the hands and feet, muscle cramps, carpopedal spasms, and laryngospasms. The classic physical signs are Trousseau's and Chvostek's signs.

Seizures — One of the interesting seizure findings on EEG in patients with acute hypocalcemia is both spikes ("convulsive effect") and bursts of high-voltage, paroxysmal slow waves.

Cardiovascular — Acute myocardial dysfunction is common. Clinicians should watch for prolongation of the QT interval on EKG, because it may lead to Torsades de pointes.

Papilledema — The presence of papilledema means hypocalcemia is severe.

Psychiatric — Emotional instability, anxiety, and depression are common, but severe acute hypocalcemia may cause confusional states, hallucinations, and frank psychosis.

Fortunately, most signs and symptoms of acute hypocalcemia are reversible with repletion.

#electrolytes

References:

1. Bove-Fenderson E, Mannstadt M. Hypocalcemic disorders. Best Pract Res Clin Endocrinol Metab. 2018 Oct;32(5):639-656. doi: 10.1016/j.beem.2018.05.006. Epub 2018 May 28. PMID: 30449546.

2. Schafer AL, Shoback DM. Hypocalcemia: Diagnosis and Treatment. [Updated 2016 Jan 3]. In: Feingold KR, Anawalt B, Blackman MR, et al., editors. Endotext [Internet]. South Dartmouth (MA): MDText.com, Inc.; 2000-. Available from: https://www.ncbi.nlm.nih.gov/books/NBK279022/

3. Pepe J, Colangelo L, Biamonte F, Sonato C, Danese VC, Cecchetti V, Occhiuto M, Piazzolla V, De Martino V, Ferrone F, Minisola S, Cipriani C. Diagnosis and management of hypocalcemia. Endocrine. 2020 Sep;69(3):485-495. doi: 10.1007/s12020-020-02324-2. Epub 2020 May 4. PMID: 32367335.

Acute cannabis toxicity

Q: 22 years old male, visiting friends and family on Thanksgiving weekend from college, and 'chilling' at a Hookah bar is brought to the emergency room (ER) with chest pain, hyperemesis, and decreased breath sound on the right side. The probable diagnosis of acute cannabis intoxication is made. Which is more common in such clinical presentations? (select one)

A) Hyperventilation

B) Hypoventilation

Answer: A

In recent years with more acceptance of marijuana in the society and epidemic of sheesha/hookah in urban areas, inpatient physicians need to be always ready with young men presenting with acute cannabis intoxication.

The most common presenting symptom is hyperemesis, dysphoria, and/or agitation. Young men tend to inhale and hold their breath during hookah inhalation. Pneumomediastinum and pneumothorax are very common. Myocardial infarction in young adults without any prior history of heart disease is also reported.

Although in massive overdose hypoventilation/apnea may occur but is rare. By default tachypnea and hyperventilation are the norm. Other clinical symptoms are tachycardia, hypertension, dry mouth, red eye, nystagmus, ataxia, and slurred speech.

#toxicology

References:

1. Ashton CH. Pharmacology and effects of cannabis: a brief review. Br J Psychiatry 2001; 178:101.

2. Tashkin DP. Effects of marijuana smoking on the lung. Ann Am Thorac Soc 2013; 10:239.

3. Noble MJ, Hedberg K, Hendrickson RG. Acute cannabis toxicity. Clin Toxicol (Phila). 2019 Aug;57(8):735-742. doi: 10.1080/15563650.2018.1548708. Epub 2019 Jan 24. PMID: 30676820.

CXR and CAP

Q: It is conventionally believed that chest x-ray (CXR) improvement lags behind the clinical improvement in community-acquired pneumonia (CAP). But recent evidence speaks against it.

A) True

B) False

Answer: B

Evidences continue to show that conventional teaching is right and radiographic improvement usually lags behind the clinical response. The study has shown that by the end of one week in severe CAP, only a quarter of the patients show resolution of chest radiograph, though two-thirds of these patients clinically improved. And, by the end of the month, only half had Chest-X-Ray improvement.

Patients with multilobar pneumonia take longer to have radiologic resolution. Older age and underlying lung disease usually have a similar effect.

#pulmonary

#radiology

References:

1. Bruns AH, Oosterheert JJ, Prokop M, et al. Patterns of resolution of chest radiograph abnormalities in adults hospitalized with severe community-acquired pneumonia. Clin Infect Dis 2007; 45:983.

2. Mittl RL Jr, Schwab RJ, Duchin JS, et al. Radiographic resolution of community-acquired pneumonia. Am J Respir Crit Care Med 1994; 149:630.

3. El Solh AA, Aquilina AT, Gunen H, Ramadan F. Radiographic resolution of community-acquired bacterial pneumonia in the elderly. J Am Geriatr Soc 2004; 52:224.

Beta-Blocker in Grave's disease

Q: Which Beta-Blocker (BB) is usually preferred in Grave's disease? (select one)

A) Atenolol

B) Esmolol

C) Carvedilol 

D) Timolol 

Answer: Atenolol

BB in Graves' hyperthyroidism ameliorates the symptoms. Although any BB can be used Atenolol is preferred for two reasons

1. It requires only a single daily dosing 

2. It is beta-1 selective

Beta-blockers effectively control palpitations, tachycardia, tremulousness, anxiety, heat intolerance, fatigability, and shortness of breath. Patients who get BB added to thionamide respond better in controlling these symptoms in comparison to thionamide alone.

Esmolol (choice B) is only available as intravenous and is usually used only in ICU/anesthesia settings. Carvedilol (choice C)  is preferred in the management of congestive heart failure. Timolol (choice D) is preferred in ophthalmology as eye drops.

#endocrinology

References:

1. Ross DS, Burch HB, Cooper DS, et al. 2016 American Thyroid Association Guidelines for Diagnosis and Management of Hyperthyroidism and Other Causes of Thyrotoxicosis. Thyroid 2016; 26:1343.

2. Geffner DL, Hershman JM. Beta-adrenergic blockade for the treatment of hyperthyroidism. Am J Med 1992; 93:61.

3. Tagami T, Yambe Y, Tanaka T, et al. Short-term effects of β-adrenergic antagonists and methimazole in new-onset thyrotoxicosis caused by Graves' disease. Intern Med 2012; 51:2285.

CT vs MRI in NSTI

Q: Which radiographic imaging is preferred in necrotizing soft tissue infection (NSTI)? (select one)

A) CT scan

B) MRI

Answer: A

It should be emphasized first that NSTI is a clinical diagnosis and surgical evaluation/intervention should not be halted due to delay in radiographic imaging.

If radiographic imaging is readily available CT scan is preferred over MRI for a couple of reasons.

First, MRI is not as useful as CT for detection of gas in soft tissues.

Second, MRI is usually oversensitive, may overestimate deep tissue involvement, and may not reliably distinguish between necrotizing cellulitis and deeper infection.

CT scan can well define gas in soft tissues, fluid collections, absence or heterogeneity of tissue enhancement with intravenous contrast, and inflammatory changes beneath the fascia.

#radiology

#ID

References:

1. Zacharias N, Velmahos GC, Salama A, et al. Diagnosis of necrotizing soft tissue infections by computed tomography. Arch Surg 2010; 145:452.

2. Bruls RJM, Kwee RM. CT in necrotizing soft tissue infection: diagnostic criteria and comparison with LRINEC score. Eur Radiol 2021; 31:8536.

3. Schmid MR, Kossmann T, Duewell S. Differentiation of necrotizing fasciitis and cellulitis using MR imaging. AJR Am J Roentgenol 1998; 170:615.

leukocyte count and glycemic emergencies

Q:  Leukocytosis is usually proportional to the degree of ketonemia in patients with hyperglycemic emergencies.

A) True

B) False

Answer: A

By default, most patients with Diabetic ketoacidosis (DKA) and hyperosmolar hyperglycemic state (HHS - also known as hyperosmotic hyperglycemic nonketotic state - HHNK) have some degree of leukocytosis. WBC level is usually proportional to the degree of ketonemia. This leukocytosis is due to hypercortisolemia and increased catecholamine secretion.

Clinicians should be vigilant about possible underlying infection/sepsis, which may have led to this hyperglycemic emergency, particularly if there is an associated history, out of proportion high WBC account like 25,000/microL, or if there is a significant bandemia of about 10 percent.

#endocrinology

#ID

References:

1. Nematollahi LR, Taheri E, Larijani B, et al. Catecholamine-induced leukocytosis in acute hypoglycemic stress. J Investig Med 2007; 55:S262.

2. Slovis CM, Mork VG, Slovis RJ, Bain RP. Diabetic ketoacidosis and infection: leukocyte count and differential as early predictors of serious infection. Am J Emerg Med 1987; 5:1.

History of miscarriage and heart

Q: Female patients who have experienced spontaneous pregnancy loss have higher chances of having coronary heart disease (CHD)?

A) True

B) False

Answer: A

Female patients who experience spontaneous pregnancy loss (miscarriage or stillbirth) have high risk of Atherosclerotic Cardiovascular Disease (ASCVD) particularly coronary heart disease (CHD). The most probable explanation is their high level of procoagulant and proinflammatory state. Moreover, these patients also have higher risks of hypertension and diabetes.

#cardiology

#epidemiology

References:

1. Kharazmi E, Dossus L, Rohrmann S, Kaaks R. Pregnancy loss and risk of cardiovascular disease: a prospective population-based cohort study (EPIC-Heidelberg). Heart 2011; 97:49

2. Kharazmi E, Fallah M, Luoto R. Miscarriage and risk of cardiovascular disease. Acta Obstet Gynecol Scand 2010; 89:284.

3. Wagner MM, Bhattacharya S, Visser J, et al. Association between miscarriage and cardiovascular disease in a Scottish cohort. Heart 2015; 101:1954.

4. Grandi SM, Filion KB, Yoon S, et al. Cardiovascular Disease-Related Morbidity and Mortality in Women With a History of Pregnancy Complications. Circulation 2019; 139:1069.

Bedside trick - suspecting tracheal aspiration!!

Q: 72 years old male with a recent stroke and now s/p tracheostomy is recovering in ICU, and awaiting long-term care transfer. Patient is also getting tube feed. Respiratory therapist (RT) reports possible "feeding material" in tracheal suction. What is the quickest way to ascertain tracheal aspiration of tube feed?

Answer: Check the glucose level of the tracheal aspirate

One quick method of suspecting tracheal aspiration is to check glucose concentration with regular bedside glucose meters. A glucose concentration of more than 20 mg/dl of bloodless tracheal aspirate highly enhances the suspicion of tracheal aspiration.

Though evidence is not very strong for this procedure in the literature, at least it makes clinicians to be vigilant.

#procedures

#nutrition

#pulmonary

References: 

1. Clinical implications of the glucose test strip method for early detection of pulmonary aspiration in nasogastric tube- fed patients - Taehan Kanho Hakhoe Chi. 2004 Dec;34(7):1215-23

2. Comparison of blue dye visualization and glucose oxidase test strip methods for detecting pulmonary aspiration of enteral feedings in intubated adults - Chest, Vol 103, 117-121

3. Glucose content of tracheal aspirates: Implications for the detection of tube feeding aspiration. Crit Care Med 1994; 22:1557-1562

4. Glucose Content of Tracheal Aspirates - Letter to the Editor - Critical Care Medicine: Volume 23(8) August 1995 pp 1451-1452

B symptoms

Q: Which of the following is not considered a part of B symptoms? (Except one)

A) Fever

B) Sweats

C) Weight loss 

D) Fatigue

Answer: D

B symptoms specifically refer to symptoms associated with lymphoma. It has a formal definition, which requires three components

1. Persistent temperature >38°C (> 100.4°F)

2  Sweats – particularly drenching night sweats

3. Unexplained weight loss of < 10 percent of body weight in last past six months

Lymphadenopathy is generally present. B symptoms become more prominent present as disease advances.

                                  

Fatigue, pruritus, and pain are not considered B symptoms.                   

#oncology

References:

                                  

1. Cheson BD, Fisher RI, Barrington SF, et al. Recommendations for initial evaluation, staging, and response assessment of Hodgkin and non-Hodgkin lymphoma: the Lugano classification. J Clin Oncol 2014; 32:3059.

                                  

 2. Sharma R, Cunningham D, Smith P, Robertson G, Dent O, Clarke SJ. Inflammatory (B) symptoms are independent predictors of myelosuppression from chemotherapy in Non-Hodgkin Lymphoma (NHL) patients--analysis of data from a British National Lymphoma Investigation phase III trial comparing CHOP to PMitCEBO. BMC Cancer. 2009 May 18;9:153. doi: 10.1186/1471-2407-9-153. PMID: 19450285; PMCID: PMC2689869.

Signs in acute hypocalcemia

Q: Which sign is more specific to acute hypocalcemia? (select one)

A) Chvostek's sign 

B) Trousseau's sign 

Answer: B

Chvostek's sign can be elicited by tapping the facial nerve just anterior to the ear, resulting in contraction of the ipsilateral facial muscles. It mostly manifests as twitching of the lip or spasm of all facial muscles. The severity of contraction correlates well with the severity of the hypocalcemia. Chvostek's sign is not specific for hypocalcemia as it can occur in about 10 percent of the normal population.

Trousseau's sign can be elicited by inflating the sphygmomanometer above systolic blood pressure for three minutes, resulting in adduction of the thumb, flexion of the metacarpophalangeal joints, extension of the interphalangeal joints, and flexion of the wrist. The sphygmomanometer above systolic blood pressure should not be raised more than three minutes as excitability of the nerve trunk is maximum at three minutes and returns to normal even if ischemia is maintained for more than three minutes.

#electrolytes

#neurology

References:

1. Cooper MS, Gittoes NJ. Diagnosis and management of hypocalcaemia. BMJ 2008; 336:1298.

2. Thakker RV. Hypocalcemia: Pathogenesis, differential diagnosis, and management. In: Primer on the metabolic bone diseases and disorders of mineral metabolism, 6th ed, Favus MJ (Ed), American Society of Bone and Mineral Research, Washington, DC 2006. p.213.

PE in polycythemia

Q: 44 years old cab driver with a history of lung disease secondary to smoking, who also works as an auto mechanic on weekends is admitted to the ICU with sepsis due to community-acquired pneumonia. Lab exam shows polycythemia with Hemoglobin level of 17 g/dL. In polycythemia, retinal veins would be? (selected one)

A) constricted

B) dilated

Answer: B

The objective of this question is to emphasize the art of history taking and perform detailed physical examinations in the light of patient history. Determination of the core cause of polycythemia is essential as management is different between relative, primary, and secondary causes of polycythemia.

Smoking, exposure to carbon monoxide (as in auto mechanics), lung disease, and volume contraction (as possible in this patient who now presented with pneumonia) are all well-known causes of secondary reasons. Possible findings in the physical exam are:

• Cyanosis in the lips, earlobes and fingers
• Clubbing in the nailbeds
• Plethoric facies
• Dilated lingual or retinal veins
• Areas of painful erythema
• Cardiac murmurs or bruits from pulmonary arteriovenous shunts or right-to-left cardiac shunts
• Hepatomegaly and/or splenomegaly 

#physical-exam

#hematology

References:

1. Lee G, Arcasoy MO. The clinical and laboratory evaluation of the patient with erythrocytosis. Eur J Intern Med. 2015 Jun;26(5):297-302. doi: 10.1016/j.ejim.2015.03.007. Epub 2015 Mar 31. PMID: 25837692.

2. Hocking WG, Golde DW. Polycythemia: evaluation and management. Blood Rev. 1989 Mar;3(1):59-65. doi: 10.1016/0268-960x(89)90026-x. PMID: 2650777.

Campylobacter infections HIV patients

Q: Initiation of antiretroviral therapy in HIV patients may __________ the risk of Campylobacter diarrhea/infection? (select one)

A) decreases

B) increases

Answer: A

As expected, patients with human immunodeficiency virus (HIV)/acquired immunodeficiency syndrome (AIDS) have an increased incidence of campylobacter infection. Moreover, there is a higher chance of long-term carriage, giving rise to recurrent episodes of enteritis, and sometimes bacteremia. 

Once these patients are started on Antiretroviral therapy, they have a reduced risk of Campylobacter infection.

#ID

References:

1. Tee W, Mijch A. Campylobacter jejuni bacteremia in human immunodeficiency virus (HIV)-infected and non-HIV-infected patients: comparison of clinical features and review. Clin Infect Dis 1998; 26:91.

2. Larsen IK, Gradel KO, Helms M, et al. Non-typhoidal Salmonella and Campylobacter infections among HIV-positive patients in Denmark. Scand J Infect Dis 2011; 43:3.

Early PVE

Q: 62 years old male with recent Aortic Valve Replacement (AVR) due to bicuspid Aortic Valve is readmitted due to endocarditis of the new valve. In today's world, Prosthetic Valve Endocarditis (PVE) represents the majority of all cases of endocarditis? 

A) True

B) False

Answer: B

PVE is less prevalent than as thought off with only about one-fifth of all cases of endocarditis. Aortic and mitral valve replacements equally share the frequency.

If infection occurs within eight weeks it is considered early PVE. The cause is usually direct intraoperative contamination or hematogenous spread. In the first 2 months, the valve sewing ring, cardiac annulus, and anchoring sutures have not yet become covered with endothelium, making them more susceptible to direct access to organisms. Valves are still coated with fibronectin and fibrinogen, to which organisms can adhere. Perivalvular abscesses are particularly common as the annulus is commonly the primary site of infection. It occurs with both mechanical and bio-prosthetic valves, especially in early PVE.

#cardiology

#surgical-critical-care

#ID

References:

1. Bayer AS, Chambers HF. Prosthetic Valve Endocarditis Diagnosis and Management- New Paradigm Shift Narratives. Clin Infect Dis. 2021 May 18;72(10):1687-1692. doi: 10.1093/cid/ciab036. PMID: 33458755.

2. Ivanovic B, Trifunovic D, Matic S, Petrovic J, Sacic D, Tadic M. Prosthetic valve endocarditis - A trouble or a challenge? J Cardiol. 2019 Feb;73(2):126-133. doi: 10.1016/j.jjcc.2018.08.007. Epub 2018 Oct 30. PMID: 30389305.

3. Siciliano RF, Randi BA, Gualandro DM, Sampaio RO, Bittencourt MS, da Silva Pelaes CE, Mansur AJ, Pomerantzeff PMA, Tarasoutchi F, Strabelli TMV. Early-onset prosthetic valve endocarditis definition revisited: Prospective study and literature review. Int J Infect Dis. 2018 Feb;67:3-6. doi: 10.1016/j.ijid.2017.09.004. Epub 2017 Sep 19. PMID: 28935245.

WCD and pacing

Q: 68 years old male with past medical history of congestive heart failure (CHF) who was recently admitted for episodes of ventricular tachycardia (VT) due to exacerbation of CHF is discharged from hospital with Wearable Cardioverter-Defibrillator (WCD). Patient is planned to have a permanent defibrillator & pacemaker (PPM) placement next week. WCD also has temporary pacing capabilities.

A) True

B) False

Answer: B

WCD is an external device frequently prescribed on discharge to patients who have risks of death from ventricular tachycardia (VT) or ventricular fibrillation (VF). These patients are also expected to be on medications that may slow the heart rate to control VT and VF, such as beta-blockers or amiodarone. It should be understood that the approved devices do not have pacing capabilities. In the case of "brady or tachy-brady" episodes, these wearable jackets can not provide any pacing.

#cardiology

References:

1. Sharma PS, Bordachar P, Ellenbogen KA. Indications and use of the wearable cardiac defibrillator. Eur Heart J 2016.

2. Cheung CC, Olgin JE, Lee BK. Wearable cardioverter-defibrillators: A review of evidence and indications. Trends Cardiovasc Med. 2021 Apr;31(3):196-201. doi: 10.1016/j.tcm.2020.03.002. Epub 2020 Mar 12. PMID: 32205034.

3. Alsamman M, Prashad A, Abdelmaseih R, Khalid T, Prashad R. Update on Wearable Cardioverter Defibrillator: A Comprehensive Review of Literature. Cardiol Res. 2022 Aug;13(4):185-189. doi: 10.14740/cr1387. Epub 2022 Aug 15. PMID: 36128416; PMCID: PMC9451591.

MOA of high dose steroids

Q: Why do high doses of glucocorticoids work better in some medical emergencies than conventional doses?

Answer: It is a common clinical practice to use high (massive) doses of glucocorticoids in certain emergencies such as severe acute asthma, or transplant rejection. When given over 3-5 days they are also called 'pulse glucocorticoids'. Interestingly, despite its use over decades, the answer is not established with certainty as to why massive doses work in such emergencies. One plausible explanation is that the high-dose glucocorticoid dissolves in cell membranes, altering their physicochemical properties, and the activities of membrane-associated proteins. This leads to effectiveness which may not be apparent with less conventional doses.

#pharmacology

References:

1. Franchin G, Diamond B. Pulse steroids: how much is enough? Autoimmun Rev. 2006 Feb;5(2):111-3. doi: 10.1016/j.autrev.2005.08.003. Epub 2005 Aug 29. PMID: 16431338.

2. Edel Y, Avni T, Shepshelovich D, Reich S, Rozen-Zvi B, Elbaz M, Leibovici L, Molad Y, Gafter-Gvili A. The safety of pulse corticosteroid therapy- Systematic review and meta-analysis. Semin Arthritis Rheum. 2020 Jun;50(3):534-545. doi: 10.1016/j.semarthrit.2019.11.006. Epub 2019 Nov 14. PMID: 31812351.

resistance to NMB

Case; 58 years old male with history of seizures is admitted to ICU with aspiration pneumonia requiring mechanical ventilation along with sedation and neuro-muscular blockade (NMB). Despite high dose of Nimbex (Cisatracurium), adequate NMB cannot be achieved. 

Answer: Anticonvulsant and Cisatracurium-induced neuromuscular blockade interaction 

Anticonvulsants are known to interact with Cisatracurium-induced neuromuscular blockade, particularly carbamazepine. Carbamazepine not only increases the clearance of cisatracurium but also increases the resistance to the neuromuscular blocking effect of cisatracurium. Higher doses of cisatracurium may be required in patients on chronic carbamazepine therapy. 

A similar effect has been reported with phenytoin. #pharmacology 

References: 

1. Richard A, Girard F, Girard DC, Boudreault D, Chouinard P, Moumdjian R, Bouthilier A, Ruel M, Couture J, Varin F. Cisatracurium-induced neuromuscular blockade is affected by chronic phenytoin or carbamazepine treatment in neurosurgical patients. Anesth Analg. 2005 Feb;100(2):538-544. doi: 10.1213/01.ANE.0000143333.84988.50. PMID: 15673889. 

2. Koenig MH, Edwards LT. Cisatracurium-induced neuromuscular blockade in anticonvulsant treated neurosurgical patients. J Neurosurg Anesthesiol. 2000 Oct;12(4):314-8. doi: 10.1097/00008506-200010000-00003. PMID: 11147379.

Pregnancy and percutaneous kidney biopsy

Q: Pregnancy is a contraindication to percutaneous kidney biopsy?

A) True

B) False

Answer: B

In early stages of pregnancy, percutaneous kidney biopsy can be performed in the prone position. In later stages, patient can be placed in the sitting or lateral decubitus position. Complication rates are similar as in nonpregnant patients. 

Said that it is not an easy decision. Prudent thing would be to wait till postpartum period, if biopsy is not an urgency to avoid any potential maternal-fetal morbidity.

#ob-gyn

#procedures

#nephrology

References:

Moguel González B, Garcia Nava M, Orozco Guillén OA, et al. Kidney biopsy during pregnancy: a difficult decision. A case series reporting on 20 patients from Mexico. J Nephrol 2022; 35:2293.

Kuller JA, D'Andrea NM, McMahon MJ. Renal biopsy and pregnancy. Am J Obstet Gynecol 2001; 184:1093.

Day C, Hewins P, Hildebrand S, et al. The role of renal biopsy in women with kidney disease identified in pregnancy. Nephrol Dial Transplant 2008; 23:201.

Somogyi hypothesis

Q: Somogyi hypothesis is a dangerous phenomenon in patients with brittle blood sugar issues, and should particularly be watched in ICU? 

A) True

B) False

Answer: B

Somogyi hypothesis once very popular in diabetic literature has now been discredited. Somogyi hypothesis states that nocturnal hypoglycemia causes hyperglycemia the following morning. It has now almost proven that patients with morning hyperglycemia usually have high blood glucose at night. Other reasons to have morning hyperglycemia are nocturnal growth hormone secretion and hypoinsulinemia.

Also, the myth should be busted that nocturnal hypoglycemia awakens patients from the sleep. This is not true even in patients who have insulin pumps i.e., continuous subcutaneous insulin infusion (CSII). This is due to the fact that sympathoadrenal responses to hypoglycemia are diminished during sleep, which means defense against hypoglycemia is reduced, and people with diabetes are less likely to be awakened by autonomic symptoms.

#endocrinology

References:

1. Tordjman KM, Havlin CE, Levandoski LA, et al. Failure of nocturnal hypoglycemia to cause fasting hyperglycemia in patients with insulin-dependent diabetes mellitus. N Engl J Med 1987; 317:1552.

2. Jones TW, Porter P, Sherwin RS, et al. Decreased epinephrine responses to hypoglycemia during sleep. N Engl J Med 1998; 338:1657.

3. Banarer S, Cryer PE. Sleep-related hypoglycemia-associated autonomic failure in type 1 diabetes: reduced awakening from sleep during hypoglycemia. Diabetes 2003; 52:1195.

SIADH vs CSW in SAH

Q: Which is more common in subarachnoid hemorrhage (SAH)? (select one)

A) Syndrome of inappropriate antidiuretic hormone secretion (SIADH)

B) Cerebral salt wasting (CSW)

Answer: A

Due to its novel presentation, CSW is often reflexly get over-diagnosed in SAH, whenever hyponatremia is manifested. In fact, hyponatremia in SAH is almost always due to SIADH unless ruled out. It is always hard to differentially diagnose both conditions as they have similar manifestations. Clinical exam plays an important role in the diagnosis of CSW with hypotension, decreased skin turgor, and possibly increased blood urea nitrogen/serum creatinine ratio (signs of volume depletion). 

The major differential diagnosis point is urine sodium concentration, which should be low in SIADH but in CSW.

#electrolytes

#neurology

#nephrology

References:

1. Sterns RH, Silver SM. Cerebral salt wasting versus SIADH: what difference? J Am Soc Nephrol 2008; 19:194.

2. Deslarzes T, Turini P, Friolet R, Meier P. Perte de sel d'origine cérébrale versus sécrétion inappropriée d'hormone antidiurétique [Cerbral salt wasting syndrome versus SIADH]. Rev Med Suisse. 2009 Nov 11;5(225):2281-4. French. PMID: 19999317.

3. Maesaka JK, Imbriano L, Mattana J, Gallagher D, Bade N, Sharif S. Differentiating SIADH from Cerebral/Renal Salt Wasting: Failure of the Volume Approach and Need for a New Approach to Hyponatremia. J Clin Med. 2014 Dec 8;3(4):1373-85. doi: 10.3390/jcm3041373. PMID: 26237607; PMCID: PMC4470189.

Picture Diagnosis

Q; 32 years old female with history of brittle diabetes is admitted to ICU with lower abdominal pain and probable diagnosis of urosepsis. KUB is below?

Diagnosis: Emphysematous cystitis 

Emphysematous cystitis is a rare entity characterized by pockets of gas in and around the bladder wall produced by bacterial or fungal fermentation. Risk factors include female sex, immunocompromised state, diabetes mellitus, recurrent urinary tract infections, neurogenic bladder and few others. It is less lethal than emphysematous pyelonephritis and rarely needs surgical intervention. Treatment is via appropriate antibiotic therapy.

#ID

#urology

Reference:

Amano M, Shimizu T. Emphysematous cystitis: a review of the literature. Intern Med. 2014;53(2):79-82. doi: 10.2169/internalmedicine.53.1121. Epub 2012 Mar 1. PMID: 24429444.

total urine output per day from spot urine analysis

Q: How total urine output per day can be estimated from spot urine analysis?

Answer: It can easily be calculated by the following formula

 Estimated daily urine output  =  100  ÷  Urine creatinine concentration (mg/dL)

This formula is applicable only if patient has stable glomerular filtration rate (GRF). Creatinine concentration can be obtained from a spot urine sample.

#nephrology

Reference:

Dong Y, Silver SM, Sterns RH. Estimating urine volume from the urine creatinine concentration. Nephrol Dial Transplant. 2023 Mar 31;38(4):811-818. doi: 10.1093/ndt/gfab337. PMID: 34850163.

Reversing HD catheter port

Q: 53 years old patient in ICU getting hemodialysis (HD). Nurse reports resistance with flow. ICU resident asked dialysis nurse to reverse the dialysis catheter's ports. By convention, red port is to draw blood from the patient, and the blue port is to return the blood from the dialysis machine back to the patient?

A) True

B) False

Answer: A

Hemodialysis catheter by default has two lumens - red and blue. The red port is by convention the draws blood from the patient and send to HD machine. The blue port returns blood from the dialysis machine back to the patient. Many times clinicians reverse the direction to improve the flow - but this may increase the risk of recirculation, reduced clearance, and possibly inadequate dialysis, as the tip configuration of catheter is not designed for this. 

Said that many catheters are now designed as self-centering with a built-in curvature designed to push the tip of the catheter away from wall of the vessel or heart chamber. This maximize the flow and may reduce recirculation when used in a reverse configuration. 

#procedures

References:

1. Silverstein DM, Trerotola SO, Clark T, et al. Clinical and Regulatory Considerations for Central Venous Catheters for Hemodialysis. Clin J Am Soc Nephrol 2018; 13:1924.

2. Vesely TM, Ravenscroft A. Hemodialysis catheter tip design: observations on fluid flow and recirculation. J Vasc Access 2016; 17:29.

3. Van Der Meersch H, De Bacquer D, Vandecasteele SJ, et al. Hemodialysis catheter design and catheter performance: a randomized controlled trial. Am J Kidney Dis 2014; 64:902.

Mannitol, renal failure, Na and K

Q: If Mannitol is given to a patient with renal failure it may cause? (select one)

A) Hyponatremia and hyperkalemia

B) hypernatremia and hypokalemia

Answer: A

The objective of this question is to lead students to mechanism of mannitol and electrolyte behavior across the cell membrane. In patients with renal failure, mannitol is retained in the circulation, which leads to increased plasma osmolality. This mechanism is very much like hyperglycemia. This increased plasma osmolality, moves water and potassium out of cells, causing extracellular fluid volume expansion, pulmonary edema, (dilutional) hyponatremia, and hyperkalemia.

In patients, with normal kidneys, mannitol is usually tolerable as it does not get retained in the system.

#electrolytes

References:

1. Aviram A, Pfau A, Czaczkes JW, Ullmann TD. Hyperosmolality with hyponatremia, caused by inappropriate administration of mannitol. Am J Med 1967; 42:648.

2. Fanous AA, Tick RC, Gu EY, Fenstermaker RA. Life-Threatening Mannitol-Induced Hyperkalemia in Neurosurgical Patients. World Neurosurg 2016; 91:672.e5.