Internal Medicine
Certification Exam Review

Educational Objective:

Know how to calculate mean arterial pressure and pulse pressure.

Key Point:

In hypovolemic shock, it is recommended that fluid be replaced to achieve a mean arterial of 65 mg Hg.

Explanation:

The correct formula is diastolic pressure + (pulse pressure ÷ 3). Because this is not an obvious formula, a good way to remember this is the mnemonic MAP (Minimal And Pulse pressure ÷ 3).

The other formulas listed have no relevance to the calculation of mean arterial pressure. Pulse pressure is defined as the difference between systolic and diastolic pressure; a patient with a blood pressure of 120/80 mm Hg has a pulse pressure of 40 mm Hg.

References:

Fabian V, Havlik J, Dvorak J, et al. Differences in mean arterial pressure of young and elderly people measured by oscilometry during inflation and deflation of the arm cuff. Biomed Tech (Berl). 2016. [Epub ahead of print].

Otero RM, et al. Approach to the patient in shock. In: Tintinalli JE, et al, eds. Tintinalli’s Emergency Medicine: A Comprehensive Study Guide. 7th ed., 2011.

Educational Objective:

Identify the clinical characteristics of tubal pregnancy.

Key Point:

Absent menses, elevated HCG level, and ultrasound showing an adnexal mass but no intrauterine evidence of intrauterine pregnancy is diagnostic of a tubal pregnancy.

Explanation:

This patient has a tubal pregnancy. Tubal pregnancies occur in 1-2% of all pregnancies and are the most frequent cause of death in pregnant patients in the first trimester. The absence of menses and an HCG level of 4,000 confirm the presence of a pregnancy. The ultrasound shows no evidence of an intrauterine pregnancy. This combination of findings effectively eliminates the other diagnoses, all of which could present with similar symptoms.

Methotrexate can be an appropriate therapy for hemodynamically stable patients with small, unruptured ectopic pregnancies. In the presence of tubal rupture, surgical intervention is recommended and often can be completed successfully via laparoscopy.

References:

American College of Obstetricians and Gynecologists. ACOG practice bulletin no. 94: medical management of ectopic pregnancy. Obstet Gynecol. 2008;111:1479-1485. 

Houry DE, Salhi BA. Acute complications of pregnancy. In: Marx JA, et al, eds. Rosen’s Emergency Medicine: Concepts and Clinical Practice. 7th ed., 2009:2279-2297.

Pope ET, Kellerman RD. Pregnancy and Antepartum Care. Conn’s Current Therapy. 2017; 18: 1097-1113

Educational Objective:

Select testing that confirms the diagnosis of glaucoma.

Key Point:

Automated perimetry confirms the diagnosis of glaucoma.

Explanation:

Open-angle glaucoma is defined as a chronic condition in which there is evidence of optic nerve damage.

The presence of elevated intraocular pressure is not sufficient to make a diagnosis of open-angle glaucoma unless there is evidence of optic nerve damage. The finding of a hollowed-out appearance of the optic nerve also known as "cupping of the disc" on funduscopy may be suggestive of glaucoma but is not confirmatory as some people with no ocular pathology may have cupping present.  Automated perimetry, by showing a characteristic visual field loss, is a much more reliable test that confirms the presence of optic nerve damage. . Confrontational field testing is not a test for glaucoma

References:

Gupta D, Chen PP. Glaucoma. Am Fam Physician. 2016 Apr 15;93(8):668-74.

Mantravadi AV, Vadhar N. Glaucoma. Prim Care. 2015 Sep;42(3):437-49.

Educational Objective:

Discuss how to diagnose folliculitis barbae.

Key Point:

Folliculitis barbae is an infection/inflammation of the hair follicles that sometimes presents with pustules.

Explanation:

This patient has folliculitis barbae, which defined histologically defined as the presence of inflammatory cells within the hair follicle, creating a follicular-based pustule. Folliculitis barbae is very common in areas covered with hair such as the back of the neck, face, and groin. Shaving commonly aggravates the area and can lead to constant reinfection. The most common cause of folliculitis barbae is infection with Staphylococcus aureus, but other less common causes are infections with Pseudomonas aeruginosa ("hot tub" folliculitis), viruses, and fungi. The best treatment for folliculitis barbae involves warm compresses to decrease the inflammation, antibiotic ointment like mupirocin, and oral antibiotics.

Acne represents a noninfectious form of folliculitis and can be anywhere on the face, chest, or back. Although acne is a possible diagnosis, in this instance, folliculitis barbae is the most likely condition because it is localized on the beard area and aggravated by shaving. Tinea barbae caused by a fungus would have positive findings on potassium hydroxide preparation. Candidiasis represents a fungal infection and would show hyphae on potassium hydroxide preparation. Pustular psoriasis is usually seen on the palms and soles, not in the beard area.

References:

Laureano AC, Schwartz RA, Cohen PJ. Facial bacterial infections: folliculitis. Clin Dermatol. 2014;32(6):711-714.

Stevens DL, Bisno AL, Chambers HF, et al; Infectious Diseases Society of America. Practice guidelines for the diagnosis and management of skin and soft tissue infections: 2014 update. Clin Infect Dis. 2014;59(2):e10-e52.

Educational Objective:

Identify complications of status epilepticus.

Key Point:

Rhabdomyolysis, lactic acidosis, respiratory acidosis, and hyperglycemia are known complications of status epilepticus.

Explanation:

Common systemic manifestations of convulsive activity include hypertension, tachycardia, variable alterations of respiration (ranging from tachypnea to apnea), and hyperglycemia. With ongoing seizures, skeletal muscle damage and lactic acidosis may develop. Frank rhabdomyolysis may ensue.

Hyperglycemia, not hypoglycemia, may occur in patients with status epilepticus. Hyperthermia (not hypothermia) is another rare complication of status epilepticus. Respiratory acidosis, not metabolic alkalosis, may be seen and is the result of hypoventilation.

Ideally, treatment for status epilepticus should be initiated within the first 5 minutes of continuous seizure activity. This, or 2 seizures occurring within 30 minutes without the patient regaining consciousness, currently defines the term status epilepticus.

References:

Rabin E, Jagoda A.Seizures (chapter 92). In:Wall R, et al.Rosen’s Emergency Medicine:Concepts and Clinical Practice.9th ed., 2018:1256-1264.

Fountain N. B. (2000). Status epilepticus: risk factors and complications. Epilepsia, 41 Suppl 2, S23–S30. 

Legriel, S. (2019). Hypothermia as a treatment in status epilepticus: A narrative review. Epilepsy & Behavior, 101, 106298.