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Forwarded from MohammaDJ
πŸ‡¨πŸ‡¦ MCCQE1,2 | #Case_62 | #answer
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βœ… D

πŸ”Ž Explanation

Renal biopsy (choice D) is the correct choice. The most likely cause of hematuria in this patient is IgA nephropathy and renal biopsy is necessary to make this diagnosis. IgA nephropathy typically presents in the second or third decade of life with recurrent hematuria during or immediately following upper respiratory infection. Hematuria is the only finding early in the disease. These features together with the fact that IgA nephropathy is one of the most common causes of hematuria put IgA nephropathy as the most likely diagnosis in this patient.

⚠ Measurement of serum anti-streptolysin O titer (choice A) and throat swab culture (choice B) are used to diagnose poststreptococcal glomerulonephritis, which is an unlikely cause of hematuria in this patient. Poststreptococcal glomerulonephritis occurs 1 to 3 weeks following streptococcal pharyngitis in children 2 to 12 years old. Our patient developed hematuria immediately after throat infection and is of older age.

⚠ CT scan of the abdomen (choice C) is not the correct choice. The two causes of hematuria namely renal stones and renal cell carcinoma that can be diagnosed by CT scan of the abdomen are unlikely causes of hematuria in this patient. Although renal stones can present with painless hematuria, their presentation is not related to upper respiratory infections. Also, because most renal stones are radiopaque, they are expected to be seen in the X-ray. Renal cell carcinoma usually occurs in older people between 50 to 70 year old and present with hematuria, abdominal pain, and flank mass. Other presenting symptoms include fever, anemia, and weight loss. Renal cell carcinoma is thus, an unlikely diagnosis in this patient.

⚠ Measurement of serum urea and creatinine (choice E) are nonspecific tests. Any disease that impairs renal function may raise serum urea and creatinine.

βœ…Key point:

Renal biopsy is necessary to make the diagnosis of IgA nephropathy
Forwarded from MohammaDJ
πŸ‡¨πŸ‡¦ MCCQE1,2 | #Case_63
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A 67-year-old female presents with complaints of increasing abdominal distension and intermittent vomiting for the past 4 days. She also reports abdominal pain in the periumbilical region. The pain does not radiate and is not clearly localized. Her past surgical and medical history is significant only for hypertension, which has been well controlled with hydrochlorothiazide. On examination her blood pressure is 120/75 mmHg, temperature is 37.7Β°C, pulse is 95bpm, and respirations 17/min. She appears in distress, has dry mucosa but no jaundice is observed. Abdominal auscultation reveals gurgling and tinkling sounds. Rectal examination reveals no abnormalities. Abdominal X-ray shows distended loops of small bowel with multiple air-fluid levels and pneumobilia. What is the most likely diagnosis?

a) Acute diverticulitis
b) Gallstone ileus
c) Crohn disease free perforation
d) Adhesive small bowel obstruction
e) Pseudomembranous colitis
Forwarded from MohammaDJ
πŸ‡¨πŸ‡¦ MCCQE1,2 | #Case_63 | #answer
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βœ… B

πŸ”Ž Explanation

This patient’s clinical scenario is consistent with gallstone ileus (choice B). It is an obstruction of the small bowel (at or near the ileocecal valve) due to impaction of a large (at least 2.5 cm in diameter) gallstone in the ileum after being passed through a biliary-enteric fistula. 60% are cholecystoduodenal fistulas, but cholecystocolonic and cholecystogastric fistulas
can also result in gallstone ileus. Gallstone ileus is a complication of cholelithiasis and gangrenous gallbladder. It presents with intermittent abdominal pain that is poorly localized, abdominal distention, and vomiting. Abdominal X-ray is the best initial study and usually reveals distended loops of small bowel with multiple air-fluid levels and pneumobilia (air in the biliary tract). Rigler's triad: pneumobilia (air in biliary tree), small bowel obstruction (partial or complete), gallstone (usually in right iliac fossa).

⚠ Acute diverticulitis (choice A) is incorrect. The clinical presentation of diverticulitis depends on the location of the affected diverticulum, the severity of the inflammatory process, and the presence of complications. Left lower quadrant pain is the most common presenting complaint. Plain radiograph films are usually not helpful in acute diverticulitis. In case of bowel perforation, free air may be present, but pneumobilia is not associated with this condition.

⚠ Crohn disease free perforation (choice C) is incorrect. None of the patient’s symptoms is suggestive of Crohn disease.

⚠ Adhesive small bowel obstruction (choice D) would likely occur in a patient with a history of abdominal surgery. This patient never had a surgery.

⚠ Pseudomembranous colitis (choice E) is an antibiotic-associated diarrhea most frequently caused by Clostridium difficile. This patient has no recent history antibiotic use.

βœ…Key point:

Gallstone ileus results from an impaction of a large gallstone in the ileum after being passed through a biliary-enteric fistula. It presents with abdominal distention, abdominal pain, and vomiting. Pneumobilia, air in the biliary tree, can be seen on abdominal X-ray.
Forwarded from MohammaDJ
πŸ‡¨πŸ‡¦ MCCQE1,2 | #Case_64
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A 38-year-old female presents to the family physician's office complaining of a β€˜whitish’ discharge from her both nipples, which she first noticed one week ago. She has never been pregnant and her last menstrual bleeding was three months ago. On confrontation visual field testing, she has field defects in upper and temporal quadrants of both eyes. A tumor at which of the following location could explain her signs and symptoms?

a) Sphenoidal ridge
b) Olfactory groove
c) Anterior pituitary
d) Posterior pituitary
e) Pituitary stalk
πŸ‘1
Forwarded from MohammaDJ
πŸ‡¨πŸ‡¦ MCCQE1,2 | #Case_64 | #answer
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βœ… C

πŸ”Ž Explanation

A visual field defect of the outer hemi-fields of both eyes (bitemporal hemianopia) indicates a midline lesion that affects the optic chiasm. The visual field defect more pronounced on the upper quadrants (β€˜pie in the sky’) indicates the optic chiasm is compressed from below. The location of the pituitary gland matches this description. Galactorrhea, amenorrhea,
and infertility
are seen in hvperprolactinemia, which can be caused by a tumor (adenoma) of the anterior pituitary (choice C).

⚠ Tumors of the sphenoidal ridge (choice A) and olfactory groove (choice B) compresses the optic nerve and mostly causes a monocular visual field deficit (not a bitemporal hemianopia). It also wouldn’t explain the features of hyperprolcatinemia seen in this patient.

⚠ Posterior pituitary (choice D), which stores and releases antidiuretic hormone (ADH) and oxytocin, does not form adenomas.

⚠ Craniopharyngioma is a tumor that arises from the remnants of the Rathke pouch of the pituitary stalk (choice E) and compresses the optic chiasm from above, which results a bitemporal hemianopia with a visual field defect more pronounced in the outer inferior quadrants (not the outer superior quadrant as seen in this patient).

βœ…Key point:

Bitemporal hemianopia points to a lesion compressing the optic chiasm. In a patient with bitemporal hemianopia it is important to look for features of anterior pituitary hormone dysregulation.
Forwarded from MohammaDJ
πŸ‡¨πŸ‡¦ MCCQE1,2 | #Case_65
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A 27-year-old man presented to his family physician with palpitations of about two weeks duration. The palpitations were intermittent, short-lasting, resolved spontaneously, and were not related to exertion. He had no other symptoms. His heart rate was regular at 92 beats per minute and other vital signs were stable. Examination showed the following:
- point of maximum impulse is located in the 5th intercostal space 1cm lateral to the midclavicular line;
- normal first and second heart sounds;
- midsystolic harsh murmur of grade VI/6 with maximal intensity at the left lower sternal border and did not radiate to the axilla, clavicle or carotid artery. The murmur was diminished by squatting and was louder during expiration.The rest of physical examination was normal. Which of the following is the most likely cause of this patient's heart murmur?


a) Aortic stenosis
b) Hypertrophic obstructive cardiomyopathy
c) Mitral regurgitation
d) Large ventricular septal defect complicated by pulmonary hypertension
e) Pulmonary stenosis complicated by pulmonary hypertension
Forwarded from MohammaDJ
πŸ‡¨πŸ‡¦ MCCQE1,2 | #Case_65 | #answer
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βœ… B

πŸ”Ž Explanation

Hypertrophic obstructive cardiomyopathy (HOCM) (choice B) is the most likely cause of the murmur in this patient. HOCM typically presents between 20 and 40 years of age and might be asymptomatic and diagnosed only when the characteristic murmur is found incidentally. Common symptoms include palpitations, angina, syncope or presyncope, shortness of breath with exercise or even sudden death. Physical signs of HOCM include PMI that is displaced laterally and is sustained in nature. Double or triple cardiac impulses are sometimes found. The typical murmur of HOCM is a midsystolic harsh murmur with maximal intensity along the lower sternal border or apex. Unlike most other systolic murmurs, the murmur of HOCM is diminished by squatting and is enhanced by standing because squatting increases venous return and standing decreases it. A high venous return expands the left ventricle including the point of obstruction within the ventricle and thus, softening the murmur in patients with HOCM. Our patient showed most of these and HOCM is thus the most likely cause of murmur. The table below compares the murmur of HOCM to that of aortic stenosis (AS), mitral regurgitation (MR), ventricular septal defect (VSD) and pulmonary stenosis (PS). The peachy color indicates characteristics of the murmur in our patient.

⚠ Aortic stenosis (choice A) is a rather unlikely cause of murmur in this patient. AS might start early in life but most patient develop symptoms in the 6th to 8th decades of life and they usually present with increasing breathlessness on exertion. The murmur of AS is crescendo decrescendo midsystolic murmur with maximum intensity in second intercostal space to the right of sternum and radiates to the clavicle or carotid artery. For all these reasons aortic stenosis is not the likely cause of murmur in this patient.

⚠ Mitral regurgitation (choice C) is an unlikely cause of murmur in this patient. The murmur of MR is a holosystolic rather than midsystolic with maximum intensity at the apex and it usually radiates to axilla.

⚠ Large ventricular septal defect (VSD) with pulmonary hypertension (choice D) usually results in early systolic rather than midsystolic murmur because shunting of blood decreases towards the end of systole. This is because pulmonary hypertension increases right ventricular pressure. Smaller VSDs on the other hand usually cause holosystolic murmurs. Thus, VSD is an unlikely cause of murmur in our patient.

⚠ Pulmonary stenosis (PS) complicated by pulmonary hypertension (choice E) is not the correct choice. In PS the murmur is midsystolic with maximum intensity in the left second intercostal space. Also, this murmur is louder during inspiration. PS is thus, an unlikely cause of the systolic murmur in our patient.

βœ…Key point:

Onset, area of maximum intensity and radiation of a murmur are helpful in identifying its causes. A midsystolic murmur with maximum intensity at apex or along left lower sternal border and that does not radiate is most likely due to HOCM.
❀1πŸ‘1
Forwarded from MohammaDJ
πŸ‡¨πŸ‡¦ MCCQE1,2 | #Case_66
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You are asked to see an 18-year-old man with autism in a busy walk-in clinic who presents with 4 day history of fever, malaise, and sore throat. He has brought his mother in to speak for him. She tells you that he has been making high-pitched sounds during inspiration and spitting out food that he normally enjoys eating due to pain with swallowing. She has also noticed that his voice has been muffled sounding for the last 24 hours.Vital signs: temperature 39.6Β°C, BP: 96/52 mmHg, HR: 102 bpm, RR: 12 rpm. On examination, you notice him leaning toward you. On examination of his throat you notice pooled saliva in the mouth. He has tender anterior cervical lymphadenopathy. The rest of the physical exam is normal. What is your next step in the management of this patient?

a) Reassure the patient and his mother that this is only a viral infection
b) Suggest rest, hydration, and close follow-up with their regular family physician
c) Prescribe Amoxicillin 400mg TID for 7 days with close follow-up.
d) Advise the patient and his mother to go to the emergency department for treatment.
e) Ensure the patient is calm, and call 911 for emergent transfer to the nearest emergency department
Forwarded from MohammaDJ
πŸ‡¨πŸ‡¦ MCCQE1,2 | #Case_66 | #answer
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βœ… E

πŸ”Ž Explanation

Epiglottitis is an inflammation of the epiglottitis and surrounding supraglottic structures that is typically caused by Haemophilus influenzae type B. Without immediate treatment epiglottitis can progress to life-threatening airway obstruction. On history, muffled voice, high pitched breathing (stridor), inability to swallow food (sore throat), and uncertain vaccination history all put him at significant risk for epiglottitis. The suggestive examination findings include leaning forward, drooling, fever, and tender cervical lymphadenopathy. The treatment is supportive, however, it is imperative that the patient not be disturbed and emergent transfer to a Level 3 facility be arranged for airway support.

⚠ The most common cause of epiglottitis in children is Haemophilus influenzae type B (HiB), which is gram-negative coccobacillus. Although HiB is a common cause in adults, most of time the infection results from several other bacteria (choice A).

⚠ Suggesting rest and hydration is a reasonable option for acute bronchitis (choice B) in selected patients. However, in this patient such a suggestion may result in the patient deteriorating further.

⚠ Oral amoxicillin (choice C) is an inappropriate choice for an emergent case of possible airway obstruction.

⚠ While the appropriate place for this patient is the emergency department, it is inappropriate to simply advise them to seek this on their own (choice D). This can be for various reasons including the patient/mother's incomplete understanding of the gravity of the situation, perceived inconvenience etc.


βœ…Key point:

Epiglottitis must be recognized in a febrile patient with sore throat, muffled voice, and stridor with or without a background history of incomplete immunizations. Unrecognized epiglottitis may rapidly lead to airway compromise and resultant death. Maintenance of the airway is the mainstay of treatment of epiglottitis
.
πŸ‘1
Forwarded from MohammaDJ
πŸ‡¨πŸ‡¦ MCCQE1,2 | #Case_67
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A 34-year-old male comes for a follow up of his recent lower respiratory infection treatment. Three weeks ago he had sought medical attention due to 5 days of cough, fever, and night sweats. Chest X-ray had shown pulmonary infiltrates and he was prescribed antibiotics with a presumed community-acquired pneumonia diagnosis. Today he reports that he is still coughing and has been experiencing chest pain. His past medical history is significant for ulcerative colitis, for which he has been receiving treatment for the last 3 years. Chest x-ray repeat shows disseminated pulmonary infiltrates. Laboratory studies reveal weakly acid-fast organisms. Taking his past medical history, current presentation, and all investigation results into consideration, you decide to treat him with trimethoprim- sulfamethoxazole. If his condition improved within the following 3 months, you would assume that the most probable culprit for causing his symptoms was:

a) Pneumocystis jiroveci
b) Nocardia asteroides
c) Mycobacterium tuberculosis
d) Coccidioides immitis
e) Mycoplasma pneumonia
Forwarded from MohammaDJ
πŸ‡¨πŸ‡¦ MCCQE1,2 | #Case_67 | #answer
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βœ… B

πŸ”Ž Explanation

This patient’s clinical picture is suggestive of pleuropulmonary nocardiosis caused by Nocardia asteroides (choice B). It is an acute, subacute, or chronic infectious disease that typically affects immunocompromised hosts, although cases in immunocompetent patients also have been reported. This patient’s long history of inflammatory bowel disease that was most probably treated with immunosuppressive therapy is a typical association with this infection.The disease may present with night sweats, fever, cough, and chest pain. It is characterized by multiple pulmonary infiltrates on chest X-ray with a tendency to central necrosis. Pulmonary infiltrates are often persistent for months as the disease is refractory to antibiotherapy, just as described in this patient. While diagnosis may be challenging, when it is suspected, the organisms can be visualized by a modified Ziehl-Neelsen stain such as Fite-Faraco staining. It is a weakly acid-fast organism. Despite the lack of controlled clinical trials and no general treatment guidelines for norcadiosis, sulfonamides are considered the treatment of choice. Sulfadiazine or trimethoprim-sulfamethoxazole should be given for a period of 6 months.

⚠ Pneumocystis jiroveci (choice A) also could present with cough, fever, and pulmonary infiltrates in
immunocompromised patients. Furthermore, the treatment of choice for this infection is trimethoprim-sulfamethoxazole. However, it is visualized on silver-stain and not Ziehl-Neelsen stain, as it is not an acid-fast organism.

⚠ Mycobacterium tuberculosis (choice C) is classified among unusual organisms that may cause persistent pulmonary infiltrates and just as seen in this patient, it can cause night sweats, fever, cough and is an acid-fast organism visualized on Ziehl-Neelsen stain. However, it is best treated with Isoniazid, rifampin, ethambutol, and pyrazinamide.

⚠ Coccidioides immitis (choice D) is a fungus, treated with ketoconazole.

⚠ Mycoplasma pneumonia (choice E) would probably have been cleared with antibiotics given for community acquired pneumonia. It is not an acid-fast organism.

βœ…Key point:

Pleuropulmonary nocardiosis is associated with persistent pulmonary infiltrates and may be refractory to antibiotherapy. It is a weakly acid-fast organism and the first line treatment is sulfonamides (either sulfadiazine or trimethoprim-sulfamethoxazole).
Forwarded from MohammaDJ
πŸ‡¨πŸ‡¦ MCCQE1,2 | #Case_68
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A 75-year-old female presents with a acutely swollen, painful, erythematous left knee. Symptoms have been present for 48 hours. She denies previous episodes and trauma. She admits that she had stopped her β€˜thyroid tablets’ a few months ago, as she prefers natural medicines.On clinical examination all vitals are within normal range, and the patient is afebrile. The left knee is visibly inflamed, red, swollen, and very tender to touch. There are no visible areas of penetrative skin trauma. What would be the next appropriate diagnostic step?

a) A serum thyroid stimulating hormone (TSH) level and T4 level. Stat dose of 200 micrograms levothyroxine and review in 3 days.
b) Immediate referral to an orthopaedic surgeon, as she will probably require an urgent joint replacement
c) Obtain a full blood panel including a complete blood count (CBC), serum uric acid, urea and creatinine,C-reactive protein (CRP). Give a high dose anti-staphylococcal antibiotic and high dose oral corticosteroids whilst awaiting results.
d) Sterile aspiration of synovial fluid. Request polarized light microscopy. Intra-articular corticosteroid directly post aspiration to provide symptomatic relief.
e) Sterile aspiration of synovial fluid. Request urgent microscopy, Gram stain and polarized light microscopy
Forwarded from MohammaDJ
πŸ‡¨πŸ‡¦ MCCQE1,2 | #Case_68 | #answer
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βœ… E

πŸ”Ž Explanation

The probable diagnosis in this case would be crystal-induced arthritis (gout or pseudogout). Septic arthritis would need to be excluded, but is less likely in a elderly afebrile patient, with no obvious infective source. Sterile aspiration of the affected knee would be the next diagnostic step. In cases of acute monoarthritis, the synovial fluid should always be sent for microscopy and gram stain to exclude septic arthritis. Synovial fluid polarized light microscopy is diagnostic in crystal-induced arthritis and differentiates between the different types of crystals. Gout causes monosodium urate crystals, which are strongly negative birefringent, and needle-like. Calcium pyrophosphate crystal deposits (CCPD) are seen in cases of β€˜pseudogout’, they are weakly positive birefringent, rhomboid or rod-shaped. Of the crystal-induced arthropathies, acute calcium pyrophosphate crystal arthritis (CPPD or pseudogout) would be the most likely diagnosis. It tends to affect elderly patients, larger joints more commonly and is associated with hypothyroidism.

⚠ A serum TSH and T4, with high dose levothyroxine (choice A), is incorrect. Hypothyroidism does not typically present with acute inflamed mono-arthritis, it may present with generalized arthralgia. The management of the acute arthritis should take priority; the hypothyroidism should be managed thereafter.

⚠ Immediate referral to an orthopaedic surgeon, as she will probably require a urgent joint replacement (choice B), is incorrect. Acute mono-arthritis should be managed as soon as possible. Diagnostic aspiration of the synovial fluid should be performed immediately, to aid in the diagnosis and to exclude septic arthritis. Joint replacement is not the preferred treatment for septic or crystal-induced arthritis.

⚠ Performing a full blood panel, with high dose anti-staphylococcal antibiotics and oral corticosteroids (choice C), is incorrect. The blood results might aid in differentiating between an infective and non-infective process, but would not be diagnostic. It is preferable to first make a plausible diagnosis before starting treatment. Antibiotics would be indicated once the diagnosis of infective arthritis has been established by synovial tap. Surgical drainage and arthroscopy of the joint would then be indicated. Corticosteroids would be absolutely contraindicated in infective arthritis, but would be a treatment option in crystal-induced arthritis.

⚠ Sterile aspiration of synovial fluid, request polarized light microscopy. Post aspiration intra-articular corticosteroids (choice D), is incorrect. In cases of acute monoarthritis, the synovial fluid should always be sent for microscopy and gram stain to exclude septic arthritis. Septic arthritis is less likely in the afebrile patient with intact skin, but has not been ruled out, as hematological spread from a distant site has not been excluded. Crystal-induced arthritis and infective arthritis may occur simultaneously. Corticosteroids are absolutely contraindicated in septic arthritis.

βœ…Key point:

Sterile aspiration of synovial fluid is the diagnostic test of choice in patients with a mono-arthritis, and should be performed without delay. Polarized light microscopy differentiates between the different types of crystal-induced arthropathies.
Forwarded from MohammaDJ
πŸ‡¨πŸ‡¦ MCCQE1,2 | #Case_69
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A 47-year-old man presented with fatigue. Past medical history was not remarkable. Other than pallor and tachycardia, physical examination was otherwise normal. Complete blood count results were as follows:
Hemoglobin level: Low
hematocrit: Low
Red cell count: Low
Reticulocyte count: Low
Platelet count: Low
Red cell distribution width: Normal
White cell count: Normal
Differential white cell count: Normal
Red cell indices: Normocytic normochromic
Erythrocyte sedimentation rate: Normal

Which of the following investigations should be done next?


a) Direct Coomb's test
b) Indirect Coomb’s test
c) Gastrointestinal work-up
d) Bone marrow biopsy
e) Glucose 6 phosphate dehydrogenase assay
Forwarded from MohammaDJ
πŸ‡¨πŸ‡¦ MCCQE1,2 | #Case_69 | #answer
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βœ… D

πŸ”Ž Explanation

Bone marrow biopsy (choice D) is the investigation to be done next. The results of the CBC point towards the diagnosis of aplastic anemia or a myelodysplastic syndrome. In these disorders anemia is normocytic normochromic and more than two cell lines (red cells and platelets in our patient) are usually affected. Because the bone marrow is suppressed in these disorders, it can not respond with increased reticulocyte production and reticulocyte count is thus, low.

⚠ Direct Coomb’s test (choice A) and Indirect Coomb’s test (choice B) Glucose 6 phosphate dehydrogenase (G6PD) assay (choice E) are not the correct choices. These tests would be done if hemolytic anemia were suspected. In hemolytic anemia the bone marrow responds with brisk erythropoiesis associated with pouring of large numbers of reticulocytes in Peripheral blood. Contrary to this, our patient had low reticulocyte count making hemolytic anemia a rather unlikely possibility and Coomb’s test whether direct or indirect and G6PD assay are unlikely to be helpful.

⚠ Gastrointestinal work-up (choice C) is not the correct choice. In patients with anemia, GI work-up is used to evaluate acute or chronic GI bleeding. If anemia is due to acute GI bleeding, reticulocytosis is expected which is not the case in our patient who had low reticulocyte count. On the other hand, if anemia is due to chronic GI bleeding, it will be of the microcytic hypochromic type caused by iron deficiency resulting from chronic blood loss. Our patient had normocytic normochromic anemia, instead.

βœ…Key point:

In normocytic anemia with low reticulocyte count, bone marrow biopsy is the investigation of choice
πŸ‘2
Forwarded from MohammaDJ
πŸ‡¨πŸ‡¦ MCCQE1,2 | #Case_70
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A 56-year-old known hypertensive patient presents to the emergency department with mild dizziness of a day's duration. By careful inquiry it is confirmed that he has vertigo. He has no tinnitus or any other complaint. Physical examination: heart rate 87 beat per minute, respiratory rate 18 per minute, blood pressure 138/87 mmHg and body temperature 37.1Β°C; unidirectional nystagmus that disappeared during visual fixation; rest of physical examination is normal.
Which of the following factors favours a peripheral over a central cause of vertigo?


a) Acute onset of vertigo
b) Mild nature of vertigo
c) Absence of tinnitus
d) Association with unidirectional rather than bidirectional nystagmus
e) Disappearance of nystagmus during visual fixation
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βœ… E

πŸ”Ž Explanation

Vertigo, the sense of movement of oneself or the environment or simple feeling of spinning, is caused by lesions of the peripheral (located in the bony labyrinth) or central components of the vestibular system (located in spinal cord, brain stem, cerebral cortex and cerebellum). Vertigo can be physiological and examples of this include vertigo with extreme head extension, height vertigo or vertigo following a spin. Pathological causes include benign paroxysmal positional vertigo, Meniere’s disease, vestibular neuritis, acoustic neuroma or vascular lesions of the above brain areas. Normally, projections from the peripheral components of the vestibular system to the cerebral cortex make us conscious of our head position and movement, projections to spinal cord helps us maintain postural stability and projections to the cerebellum modulate the vestibuloocular reflex (VOR) that controls visual stability during head movement. The efferent limb of the VOR is carried through the 3rd, 4th and 6th cranial nerves and is normal in peripheral lesions of the vestibular system. Thus, disappearance of nystagmus during visual fixation (choice E) is typical of nystagmus accompanying vertigo caused by peripheral lesions (Labyrinth lesions). Nystagmus accompanying vertigo caused by central lesions (lesions of brain stem or cerebellum) usually persists during visual fixation due to disruption of this efferent limb of the VOR.

⚠ Vertigo may be of acute onset (choice A) in both peripheral and central lesions. Whether onset is acute or chronic depends on the cause rather than site of lesion. Ischemia of the labyrinth (peripheral) or the brain stem or cerebellum (central) can lead to abrupt onset of vertigo.

⚠ Mild nature of vertigo (choice B) favours central rather than peripheral causes of vertigo. Vertigo due to peripheral causes is usually severe.

⚠ Absence of tinnitus (choice C) favours central rather than peripheral causes of vertigo. Vertigo is usually not accompanied by tinnitus when caused by central lesions.

⚠ Unidirectional nystagmus (choice D) can be associated with both central and peripheral causes of nystagmus.

βœ…Key point:

Simple bedside tests can help differentiate between central and peripheral causes of nystagmus. For example, nystagmus that persists during visual fixation favours central over peripheral causes of vertigo.
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πŸ‡¨πŸ‡¦ MCCQE1,2 | #Case_71
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A 7-year-old girl presented with fever, sore throat and tender anterior lymphadenopathy. With appropriate work-up, the diagnosis of streptococcal pharyngitis was established. Because she had two attacks of otitis media in the past year, complete blood count (CBC) was performed. The only positive findings in the CBC were as follows: white cell count of 12.5 x 109/L, platelet count of 650 x 109/L and an erythrocyte sedimentation rate of 19 mm/hour. She was prescribed amoxicillin 40mg/kg. Regarding this patient's thrombocytosis, which of the following is the most appropriate next step in management?

a) Order bone marrow biopsy
b) Order lymph node biopsy
c) Order platelet retention test
d) Order platelet release reaction
e) Repeat platelet count in four weeks
Forwarded from MohammaDJ
πŸ‡¨πŸ‡¦ MCCQE1,2 | #Case_71 | #answer
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βœ… E

πŸ”Ž Explanation

Platelets are acute phase reactants and their number increases with infections and other inflammatory conditions (reactive thrombocytosis). As reported by Andrew and Schafer, only 8 out of 10,000 patients with incidental thrombocytosis were found to have high platelet counts a few weeks later. Therefore, given this patient's clinical scenario (incidental finding), platelet count should be repeated a few weeks later (choice E).

⚠ Bone marrow biopsy to rule out essential thrombocytosis (choice A) should be done only after reactive thrombocytosis is excluded.

⚠ There is no clear indication for lymph node biopsy (choice B) in this patient. The tender anterior cervical lymphadenopathy is most likely due to streptococcal pharyngitis and will usually subside in a few weeks. In addition, our patient did not have symptoms, signs or lab results suggestive of diseases associated with lymphadenopathy and thrombocytosis like myeloproliferative diseases.

⚠ Platelet retention test (choice C) is used to evaluate adhesiveness of platelets, which is known to be reduced in some diseases like Von Willebrand disease, uremia and thrombocytosis that accompany myeloproliferative diseases. Our patient, however, did not have any symptoms or signs suggestive of any of these diseases. Ruling out of reactive thrombocytosis is the priority in this patient.

⚠ Platelet release reaction (choice D) is used to evaluate ability of platelets to release their granules when activated.
When platelets fail to release their granules, primary hemostasis is impaired and bleeding tendency might result. Our patient did not have bleeding tendency to suggest such an abnormality and ruling out reactive thrombocytosis is the priority in this patient.

βœ…Key point:

Like ESR and CRP, platelets are acute phase reactants and platelet count can increase in response to infection. In presence of infection, reactive thrombocytosis should be excluded by repeating platelet count in four to six weeks before proceeding to any further investigation
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Forwarded from MohammaDJ
πŸ‡¨πŸ‡¦ MCCQE1,2 | #Case_72
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A 36-year-old female, housewife, got admitted with a six day history of fever with rigors and chills, non-productive cough, pleuritic chest pain on the right side, and increased shortness of breath. While examining her, she was found to be febrile with a temperature of 37.8Β°C, O2 sats were 89% on air and examination of chest revealed dull percussion note in right middle chest with inspiratory crackles and bronchial breath sounds. Moreover, she had a rash on the face, arms and
legs resembling the rash of erythema multiforme. Investigations carried out were:
Hemoglobin: 85 g/L
White blood cell count: 6 x 109/L
Platelets: 140 x 109/L
Sodium: 126 mmol/l
AST: 65 U/l
ALT: 79 U/l
Albumin: 36 g/l
Peripheral blood film showed red cell agglutination Which of the following diagnosis is most consistent with the clinical picture described above?


a) Legionnaires disease
b) Community acquired pneumonia
c) Aspergilloma
d) Suppurative pneumonia
e) Healthcare-associated pneumonia
Forwarded from MohammaDJ
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βœ… B

πŸ”Ž Explanation

A subacute onset of fever with rigors and chills, non-productive cough, shortness of breath and pleuritic chest pain with findings of right middle lobe consolidation are consistent with community acquired pneumonia (CAP) (choice B). However, presence of erythema multiforme, low hemoglobin, agglutination on peripheral blood smear and hyponatremia point towards the diagnosis of (CAP) most likely due to mycoplasma pneumonia. Low hemoglobin is due to autoimmune hemolytic anemia due to formation of cold agglutinins. Whereas hyponatremia is due to syndrome of inappropriate ADH (SIADH) secretion associated with mycoplasma pneumomiae Community acquired pneumonia (CAP) is diagnosed outside of the hospital in ambulatory patients who are not residents of nursing homes or other long-term care facility. It may also be diagnosed in a previously ambulatory patients within 48 hours after admission. Most patients with CAP experience an acute or subacute onset of fever, cough with or without sputum production and dyspnea. Other common symptoms include night sweats, chills, rigors, chest discomfort, pleurisy, hemoptysis, fatigue, myalgias, anorexia, headache, and abdominal pain. Common physical findings include fever, tachypnea, tachycardia, and arterial oxygen desaturation. Chest examination often reveals inspiratory crackles and bronchial breath sounds with a dull percussion note. The clinical evaluation is < 50% sensitive compared to chest imaging for the diagnosis of CAP. In most patients, therefore, a chest radiograph is essential to the evaluation of CAP.

⚠ Legionnaires disease (choice A) is caused by Legionella pneumophila and is responsible for causing atypical pneumonias in both immunocompetent and immunocompromised individuals. Although the clinical picture mimics one of Legionnaires disease, lack of history of exposure to hot water tanks, cooling towers, and evaporative condensers of large air conditioning systems, such as those commonly found in hotels and large office buildings, makes it less likely to be the cause of this patient's disease.

⚠ Aspergilloma (choice C) is caused by Aspergillus fumigatus, a fungus. Upper lobes are frequently involved and fungal balls readily form in tuberculous cavities. Patients are usually asymptomatic with tumor-like opacity on chest X-ray.

⚠ Suppurative pneumonia (choice D) is characterized by cough with large amounts of sputum, sometimes fetid and blood stained. Moreover, there is high remittent pyrexia, digital clubbing (10 to 14 days) and presence of pleural rub in addition to the signs of consolidation in the chest X-ray.

⚠ Healthcare-associated pneumonia (choice E) is the development of pneumonia in a person who has spent at least 2 days in hospital with the last 90 days, or has attended hemodialysis unit, received intravenous antibiotics, or been a resident of a nursing home or other long-term care facility. As there is no such history, therefore health care associated pneumonia is less likely.

βœ…Key point:

Community acquired pneumonia caused by Mycoplasma pneumoniae is one of the forms of atypical pneumonia characterized by erythema multiforme, hemolytic anemia and hyponatremia in addition to presentation of typical
pneumonia.
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