Family Medicine Board Review

Educational Objective:

Diagnose vitamin B12 deficiency based on characteristic neurologic signs and symptoms, particularly in patients with a history of bariatric surgery.

Key Point:

Patients with vitamin B12 deficiency typically present with peripheral neuropathies and macrocytosis.

Explanation:

This patient has a vitamin B12 deficiency. Long-term complications of malabsorptive bariatric surgery include deficiencies in folate, iron, vitamin B12, calcium, vitamin D, and copper; hyperoxaluria leading to nephrolithiasis; dumping syndrome; postprandial hypoglycemia; abdominal wall hernias; gallstones; and anastomotic stenosis. Thus, in this case, the combination of neuropathy with posterior column signs and macrocytic anemia suggests vitamin B12 deficiency. Vitamin B12 is absorbed in the terminal ileum but requires intrinsic factor from the gastric antrum to be absorbed.

References:

Kushner RF. Bariatric surgery: postoperative nutritional management. Updated April 2, 2018. Accessed April 17, 2018.

Smelt HJ, Pouwels S, Smulders JF. Different supplementation regimes to treat perioperative vitamin B12 deficiencies in bariatric surgery: a systematic review. Obes Surg. 2017;27(1):254-262.

Educational Objective:

Discuss awake prone positioning to relieve respiratory distress in pregnant patients with COVID-19.

Key Point:

Awake prone positioning is acceptable and feasible for pregnant and immediately post-partum patients. Depending on the patient’s pregnancy or post-partum degree of comfort, awake prone positioning can be performed in the left lateral decubitus or the fully prone position. Awake prone positioning is only recommended for patients that do NOT meet intubation criteria (e.g. continued hypoxia despite maximum non-invasive oxygen therapy, altered mental status, or unprotected airway).

Explanation:

Prone positioning improves oxygenation in both pregnant and nonpregnant patients by increasing ventilation-perfusion matching through the recruiting of collapsed alveoli in the dorsal lungs.

Indications: The NIH COVID-19 treatment guidelines state that for both pregnant and non-pregnant patients, appropriate candidates for awake prone positioning are those who are able to adjust their position independently and tolerate lying prone or in the left lateral decubitus position and who do NOT meet intubation criteria (e.g. continued hypoxia despite maximum non-invasive oxygen therapy, altered mental status, or unprotected airway).

Contraindications: Awake prone positioning is contraindicated in patients who meet intubation criteria (editor’s note: e.g. altered mental status or unprotected airway). In other words, awake prone positioning is not an alternative to intubation, when intubation is indicated. Awake prone positioning is also contraindicated in hemodynamically unstable patients, patients who recently had abdominal surgery, and patients who have an unstable spine. 

In pregnant or postpartum (including immediately post-delivery) patients with ongoing hypoxemia, awake prone positioning is typically done for 2 hours in each position.

Proning of intubated patients: A trial of prone positioning is also recommended for intubated patients with refractory hypoxemia despite optimized oxygen therapy. The most critical aspect is to assure that the endotracheal tube does not dislodge or slide into a main bronchus during turning. Typically, prone positioning in intubated patients is done for 12-16 hours.

References: 

National Institute of Health. Oxygenation and Ventilation | Coronavirus Disease COVID-19 (Updated June 11, 2020) Accessed July 15, 2020)

Society for Maternal-Fetal Medicine Management Considerations for Pregnant Patients With COVID-19. Society for Maternal-Fetal Medicine Management Considerations for Pregnant Patients With COVID-19. (Published April 30, 2020) (Accessed July 15, 2020).

Educational Objective:

Identify the manifestations of transient neonatal hypoglycemia.

Key Point:

In neonates, it is common to see transient hypoglycemia after the loss of constant maternal glucose before feeding is established.

Explanation:

This infant's symptoms are most consistent with neonatal transient hypoglycemia, a common finding in neonates. With the loss of constant glucose from the mother and prior to the establishment of adequate intake, all infants are at risk for hypoglycemia. The most common presenting symptoms are jitteriness and tremulousness. The hypoglycemia is quickly reversible with oral feedings of breast milk or formula.

All of the other answer choices are less common causes of hypoglycemia in infancy. It is possible that the child is becoming septic, and this possibility can be investigated in tandem with correcting the child's hypoglycemia; however, transient neonatal hypoglycemia is the far more common cause of this set of symptoms.

References:

Thornton PS, Stanley CA, De Leon DD, et al. Recommendations from the Pediatric Endocrine Society for evaluation and management of persistent hypoglycemia in neonates, infants, and children. J Pediatr. 2015;167:238.

Zhou Y, Bai S, Bornhorst JA, et al. The effect of early feeding on initial glucose concentrations in term newborns. J Pediatr. 2017;181:112.

The CDC defines anemia in pregnancy as hemoglobin less than 11 gm/dL in the first and third trimesters and less than 10.5 gm/dL in the second trimester. Pregnancy induces a state of peripheral resistance to insulin, resulting in hyperinsulinemia, mild fasting hypoglycemia, postprandial hyperglycemia and glucosuria. Glomerular filtration rate increases by the second trimester resulting in a decrease in urea nitrogen and creatinine. Tidal volume increases, thus creating a mild respiratory alkalosis and decreased arterial PCO₂.

Educational Objective:

Describe the management of hypertension in congestive heart failure.

Key Point:

Calcium channel blockers are not first-line agents for the treatment of hypertension in patients with congestive heart failure.

Explanation:

ACE inhibitors, angiotensin II receptor blockers, beta blockers, and aldosterone antagonists all have a mortality benefit in patients with congestive heart failure. Diuretics prevent volume overload and are an important part of medication regimens for symptom control and treatment of hypertension. There is limited evidence to suggest they may also provide a mortality benefit. However, there is lack of compelling indication for the use of calcium-channel blockers in this population. First-generation dihydropyridine and nondihydropyridine calcium channel blockers have negative inotropic properties and should be avoided. Second-generation dihydropyridine derivatives, such as amlodipine and felodipine, have greater selectivity for calcium channels in vascular smooth muscle cells. Although they do not have a negative ionotropic effect, they have not been shown to improve survival in this population. However, the use of one of these agents would be appropriate as add-on therapy if blood pressure is not adequately controlled with tolerated doses of the preferred agents.

References:

Bisognano JD. Treatment of hypertension in patients with heart failure. Revised July 11, 2016. Accessed June 15, 2017.

Colucci WS. Overview of the therapy of heart failure with reduced ejection fraction. Revised June 13, 2017. Accessed June 15, 2017.

Hirbe A, et al, eds. Preventive cardiology. In: Godara H. The Washington Manual of Medical Therapeutics. 34th ed., 2014.

Yancy CW, Jessup M, Bozkurt B, et al; American College of Cardiology Foundation/American Heart Association Task Force on Practice Guidelines. 2013 ACCF/AHA guideline for the management of heart failure: a report of the American College of Cardiology Foundation/American Heart Association Task Force on practice guidelines. Circulation. 2013;128(16):e240-e327.