Biostats
GI & Renal
Pulmonary ID
Endocrinology
Eyes & Ears
100
True Positive divided by True Positive plus False Negative
What is Sensitivity?
100
A 27-year-old man has had a chronic diarrhea with weight loss of 5 kg over the past year. On physical examination there are no abnormal findings. His d-xylose absorption is abnormally low. He has elevated anti-endomysial and anti-transglutaminase antibody titers. A jejunal biopsy is performed and shown here in the right panel (compared to the normal jejunum in the left panel). He improves with a change in diet. This is the diagnosis.
What is celiac disease?
The blunting and flattening of the intestinal villi at the right are consistent with celiac disease (sprue). There is a mononuclear cell infiltrate in the mucosa and submucosa. There is an inherited sensitivity to the gliadin protein found in the gluten of grains such as wheat, barley, and rye. Anti-endomysial and anti-transglutaminase antibodies are often present. Normally, about 60% of an oral dose of xylose is passively absorbed in the proximal small intestine. The amount of xylose in the serum and in the urine can be used to evaluate mucosal absorption efficiency.
100
A 28-year-old woman is hospitalized with a 5-day history of chest pain, fever, and cough with green sputum. Two weeks ago, she developed an influenza-like illness and seemed to improve before the onset of the most recent symptoms.
On physical examination, temperature is 38.6 °C (101.5 °F), blood pressure is 150/90 mm Hg, pulse rate is 112/min, and respiration rate is 28/min. Oxygen saturation is 96% on 4L O2 via NC. Crackles are heard at the right lower lung base on pulmonary auscultation. Blood and sputum cultures are obtained. COVID-19 testing is negative.
CT shows large right sided pleural effusion.
Empiric therapy for community-acquired pneumonia is initiated with ceftriaxone, azithromycin, and vancomycin. A thoracentesis is performed with chest tube placed draining purulent fluid.
Ceftriaxone and azithromycin are discontinued on hospital day 2 when blood and sputum cultures return positive for methicillin-resistant Staphylococcus aureus with a vancomycin minimum inhibitory concentration of ≤0.5 µg/mL.
She remains febrile, but repeat blood and sputum cultures show no growth. Her temperature on hospital day 5 remains elevated at 39.2 °C (102.6 °F). This is the most reasonable next step in management.
What is consult cardiothoracic surgery for video assisted thoracoscopic surgery (VATS) for drainage and decortication?
100
A 38-year-old woman has noted painless enlargement of her neck for the past month. On physical examination she has diffuse, symmetrical thyroid enlargement without tenderness on palpation. Laboratory studies show her serum TSH is 3.1 mU/L and thyroxine 1.4 ng/dL. The thyroid diminishes in size over the next 5 years. She now has a serum TSH of 8.7 mu/L. Based upon this representative microscopic appearance of her thyroid gland early in the course of her disease, this is the antibody we expect to be present.
What is a high anti-thyroid peroxidase antibody titer?
There are lymphoid follicles present in the thyroid. Hashimoto thyroiditis is one of the most common causes for hypothyroidism in adults. Early in the course of the disease the chronic inflammation predominates, but atrophy with fibrosis ensues.
100
A 66-year-old woman is evaluated in the emergency department for severe aching pain and visual blurring in the left eye that began 2 hours ago. She describes seeing halos around lights, accompanied by a throbbing, periocular, left-sided headache and nausea. The left pupil is 4 mm in diameter and responds minimally to direct light. There is diffuse conjunctival injection, and the cornea appears cloudy. Visual acuity is 20/60. This is the most likely diagnosis.
What is acute angle-closure glaucoma?
Acute ACG presents with unilateral visual disturbance and seeing halos around lights, often accompanied by severe eye pain, eye redness, nausea, vomiting, and headache. Patients with ACG have narrow anterior chamber angles, which inhibit drainage of the aqueous fluid; see image shown.
200
(A/B)/(C/D) = AxD / BxC in case control studies
What is odds ratio?
An odds ratio (OR) is a ratio that compares the likelihood of an event happening in one group to the likelihood of it happening in another group.
200
A 19-year-old man goes to his physician for a routine check-up. The physical examination is normal except that his stool is positive for occult blood. A colonoscopy is performed and there are over 100 lesions of the colonic mucosa and biopsy of one shows findings seen here microscopically. This is the most likely diagnosis.
What is familial polyposis coli?
The small polypoid circumscribed tubular adenoma on a stalk seen here is benign, but persons with germline inheritance of the APC gene are at risk for development of colonic adenocarcinoma by their teens or 20's.
200
A 35-year-old female goes to her physician for a routine check-up. On physical examination there are no abnormal findings. A chest radiograph on shows a 3 cm discrete round right upper lobe peripheral nodule. A fine needle aspirate under CT guidance yields necrotic debris with epithelioid macrophages. A GMS stain reveals the microscopic appearance shown here. This is the most likely infectious agent causing her disease.
What is Coccidioides immitis?
These large, thick-walled spherules (one of which is rupturing) are characteristic for coccidioidomycosis, a dimorphic fungal infection that produces granulomatous disease of the lungs. The yeast phase seen here occurs in tissue, while the hyphal phase (alternating arthrospores) occurs in nature.
Most patients will start out with an acute pulmonary infection, following inhalation from the environment. Pulmonary infection may be severe, mildly symptomatic (flu-like illness), or asymptomatic. Thus, some patients are often unaware that they have developed acute pulmonary coccidioidomycosis.
>90% of patients will resolve their primary pulmonary infection without further clinical complications. 5% will develop chronic pulmonary infection with symptoms similar to tuberculosis last >6 weeks. 1-3% progress to disease dissemination beyond the lungs, specifically in immunocompromised folks.
200
A 55-year-old man has had headaches for the past 2 months. On physical examination his blood pressure is 160/110 mm Hg. Laboratory studies show serum cortisol at 8 am 15 microgram/dL, plasma renin activity 1.2 ng/mL/hr, serum aldosterone 44 ng/dL, and serum potassium 2.9 mmol/L. The gross appearance of the lesion which is causing his findings is depicted here. This is the most likely diagnosis.
What is conn syndrome?
This is an adrenal cortical adenoma. When such an adenoma secretes aldosterone (the most common cause for hyperaldosteronism) the plasma renin is decreased and there is hypokalemia.
200
A 65-year-old man is evaluated for difficulty hearing in both ears that have progressed over the past year. He reports no vertigo, depression, anxiety, or insomnia. He does not have temporomandibular joint syndrome. He has a history of loud noise exposure due to working as a concert stagehand. He has no other medical problems and takes no medications.
On physical examination, vital signs are normal. Bilateral hearing loss is noted via the whispered voice test. On otoscopic examination, the ear canal and tympanic membrane are normal. No bruit is heard. Examination of the carotid artery and the remainder of the cardiac examination are normal.
Results of laboratory studies are normal.
He has mild bilateral sensorineural hearing loss on audiometric testing.
This is the best treatment for him.
What is bilateral hearing aids?
In this patient with bilateral sensorineural hearing loss, hearing aids may be helpful.
300
True Negative divided by True Negative plus False Negative
What is Negative Predictive Value?
300
A 26-year-old man has the onset of nausea with hemoptysis and lethargy over the past 3 days. On physical examination his blood pressure is 145/95 mm Hg. His serum creatinine is 4.4 mg/dL. Urinalysis shows hematuria and proteinuria. A renal biopsy is performed and the microscopic appearance with H&E stain is shown here. This is the most likely diagnosis.
What is rapidly progressive (crescentic) glomerulonephritis (RPGN) or Goodpasture syndrome?
The epithelial crescents in Bowman's space shown here are indicative of a rapidly progressive (crescentic) glomerulonephritis (RPGN). One form of RPGN is Goodpasture syndrome, caused by anti-glomerular basement membrane antibodies, and the lungs can be affected, leading to acute pulmonary hemorrhage and hemoptysis.
300
A 65-year-old woman 18 months after deceased donor kidney transplantation presents to emergency room with increasing dyspnea over the past three weeks and new fevers. She completed trimethoprim-sulfamethoxazole prophylaxis one year prior to admission. She is hypoxic with decreased breath sounds bilaterally and fine diffuse crackles, LDH is 416, β-1,3-glucan assay positive (>500), and microscopic examination of induced sputum obtained gives the appearance seen here with GMS stain. This is the most likely diagnosis.
What is Pneumocystis jiroveci pneumonia?
The cysts of Pneumocystis jiroveci are seen here with the GMS stain. This opportunistic infection produces a widespread pneumonia with exudate filling the alveoli. This is an opportunistic infection of immunocompromised persons, like those with transplant history on immunosuppressants and HIV/AIDS.
300
A 27-year-old woman has had diarrhea with weight loss of 3 kg over the past 3 months. On physical examination her thyroid gland is diffusely enlarged and non-tender. Laboratory studies show TSH 0.3 mU/L, T4 15.8 microgram/dL, and free thyroxine 4.3 ng/mL. The representative microscopic appearance of her thyroid is shown here. What is the most likely diagnosis?
What is Graves disease?
The papillary infoldings with scalloping of colloid are typical for Graves disease, a hyperfunctioning of the thyroid gland, and the very high serum thyroxine with depressed TSH is consistent with hyperthyroidism.
300
87 year old female presents with sudden hearing loss, headaches, and right ear drainage. Medical history is noncontributory, and she takes no medications. On physical examination, vital signs are normal. Purulent drainage is seen from the right external ear canal. The right mastoid is tender. This is the most likely diagnosis.
What is otitis media (with ruptured tympanic membrane) leading to mastoiditis?
The most common bacterial pathogens are Streptococcus pneumoniae, Haemophilus influenzae, Moraxella catarrhalis, Staphylococcus aureus, and Group A Streptococcus.
400
(A/A+B)/(C/C+D) in cohort studies
What is Relative Risk?
Relative risk is a ratio that compares the likelihood of an event happening in one group to the likelihood of it happening in another group. 
400
A 42-year-old man has had episodes of substernal burning pain following meals for the past 4 years. He has no nausea or vomiting. On physical examination his stool occult blood is negative. An upper GI endoscopy is performed, and there are regions of the lower esophageal mucosa 1 to 4 cm above the gastroesophageal junction that appear erythematous. The microscopic appearance of a biopsy from his lower esophagus is shown. This is the most likely cause.
What is gastroesophageal reflux disease?
This is Barrett mucosa with columnar metaplasia as a consequence of the chronic reflux. There is a risk for subsequent development of adenocarcinoma in Barrett esophagus.
400
The 40-year-old recipient of an orthotopic heart transplant develops a fever and cough. This persists for over six weeks, and a bronchopleural fistula develops. His course is then complicated by headaches, and head CT scan reveals the presence of several brain abscesses. The gross appearance shown here is representative of his lung. This is the infectious agent that is most likely to cause his disease.
What are Nocardia braziliensis or Actinomyces israeli?
This is a chronic, abscessing pneumonia, which is most often the result in immunocompromised patients from Nocardia braziliensis or Actinomyces israeli infections.
*Orthotopic heart transplantation is a surgical procedure where a diseased heart is removed and replaced with a healthy donor heart in its original anatomical position
*Heterotopic heart transplantation: The donor heart is placed next to the recipient's heart, rather than in its original position.
400
A 39-year-old woman has noted a 'bump' on her neck for the past 6 months. On physical examination there is a firm, well-circumscribed, non-tender nodule to the right of midline in her neck. She undergoes thyroidectomy and the microscopic appearance of the lesion is shown here. This is the diagnosis.
What is papillary carcinoma of the thyroid?
Note the clear vacuolated nuclei, the papillary pattern, and the small concretion known as a psammoma body. In general, papillary carcinomas have a good prognosis.
400
A 46-year-old woman with poorly controlled Type I diabetes presents with sharp right eye pain and headaches. On physical examination, temperature is 39 °C (102.2 °F), blood pressure is 150/88 mmm Hg, and pulse rate is 102/min. The clinical appearance of the patient is shown. This is the most likely diagnosis.
What is mucormycosis?
Mucormycosis is one of the most rapidly progressing and fulminant forms of fungal infection which usually begins in the nose and paranasal sinuses following inhalation of fungal spores. The most common mucormycetes are Rhizopus arrhizus and Mucor species. Infection is acute and rapidly fatal, even with early diagnosis and treatment. Major blood vessels are invaded, with ensuing ischemia, necrosis, and infarction of adjacent tissues.
500
1/((1-RR) x CER) where RR is risk ratio and CER is control event rate
What is Number Needed to Treat? 1/Absolute Risk Reduction 
500
A 35-year-old man notes passing dark urine following a flu-like illness that has lasted for 10 days. On physical examination his blood pressure is 140/90 mm Hg. Urinalysis shows hematuria. A week later his serum creatinine is 2.9 mg/dL. A renal biopsy is performed and microscopic examination with immunofluorescence pattern shown below. This is the most likely diagnosis.
What is Berger disease (IgA nephropathy)?
This is a classic history for IgA nephropathy, which is nephritic, and thus has microscopic hematuria. The pattern of immunofluorescence staining seen here is mesangial. Some of these patients go on to develop chronic renal failure.
500
A 22-year-old man is hospitalized with a 3-day history of nonproductive cough, fever, and diarrhea. He returned 1 week ago from a tournament in Indiana with his college wrestling team. During this trip, the team used an indoor hot tub. Three other team members have developed a flu-like illness. Medical history is noncontributory, and he takes no medications.
On physical examination, temperature is 38.8 °C (101.8 °F), blood pressure is 115/75 mm Hg, pulse rate is 68/min, and respiration rate is 24/min. The examination is unremarkable.
Laboratory studies show a serum sodium level of 128 mEq/L (128 mmol/L).
This is the most likely diagnosis.
What is Legionella pneumonia?
Legionella causes 2% to 15% of community-acquired pneumonia (CAP) illnesses but is likely under-recognized. Legionella has been associated with inhalation of infectious aerosols from water sources, including air conditioning cooling units, spas, pools, fountains, and showers. Features that are variably present but may suggest Legionella include gastrointestinal symptoms (including diarrhea), altered mentation, pulse-temperature dissociation, increased liver enzymes, and hyponatremia. Legionella urinary antigen detects L. pneumophila serogroup 1; other species or serogroups would be missed through urinary antigen testing.
500
A 19-year-old woman was in good health until the day of admission, when she developed a sore throat. On physical examination she has a pharyngitis and diffusely scattered skin petechiae. The representative gross appearance of her adrenal glands is depicted here. This is the most likely diagnosis.
What is meningococcemia resulting in Waterhouse-Friderichsen syndrome?
The clinical history suggests an acute infection. The organism that can produce such a fulminant disease is Neisseria meningitidis. The adrenals are dark red-black because of the extensive hemorrhage with Waterhouse-Friderichsen syndrome.
500
A 76 year old male with HTN, HLD, and diabetes presents to the ED with sudden vision loss. Upon further questioning he states that it is more like blurred vision particularly in the center and floaters that he describes as dark spots in his field of vision. Based on the fundoscopic examination of the retina, this is the most likely diagnosis.
What is central retinal vein occlusion?
Central retinal vein occlusion is an occlusion of the main retinal vein posterior to the lamina cribrosa of the optic nerve and is typically caused by thrombosis.
