A patient with end-stage renal failure is found to be anemic. You suspect a vitamin B12 deficiency, but testing reveals that her vitamin B12 level is “low normal.”
Which one of the following laboratory test results would confirm a diagnosis of vitamin B12 deficiency?
Correct Answer C: Patients with renal failure often have normal vitamin B12 levels despite an actual deficiency. In this situation, the clinician can order a methylmalonic acid (MMA) level to confirm the diagnosis. Vitamin B12 is the necessary coenzyme in the metabolism of MMA to succinyl-CoA. Thus, in the absence of vitamin B12, MMA levels increase. Additionally, homocysteine levels would be elevated in the presence of vitamin B12 deficiency.
A 65-year-old woman was brought to the hospital with confusion. Her daughter believed that she became forgetful over the last few months.
Physical examination: she was pale, but not jaundiced or cyanosed, heart rate 102 beat per minute, respiratory rate 20 per minute, blood pressure 138/86 mmHg and body temperature 36.7°C; both upper and lower limbs appeared spastic and all reflexes were exaggerated. The rest of physical examination was normal.
Complete blood count (CBC) showed the following:
Red cell indices were as follows:
Which of the following investigations should be done next?
Correct Answer C: Serum B12 level (choice C) is the investigation to be done next. Age of the patient, neurologic symptoms and macrocytic anemia are suggestive of vitamin B12 deficiency. An investigation, to rule out vitamin B12 deficiency, is required. Serum B12 level is considered a robust investigation in ruling out vitamin B12 deficiency. Patients with vitamin B12 deficiency usually present with signs and symptoms of anemia as well as neurological and psychiatric manifestations. However, in some patients the hematological and neurological manifestations are sometimes dissociated. Also, often, asymptomatic patients are identified when a megaloblastic blood picture is encountered in a routine blood count. The neurologic manifestations are both sensory and motor and include light headedness, impaired smell and taste, numbness, progressive deterioration of visual acuity, spastic gait disturbances, forgetfulness and inability to focus. Thus, if any patient presents with any of these symptoms or signs and a clear explanation cannot be found, serum B12 should be measured.
→ Gastric biopsy (choice A) is not the correct choice. Even if gastric biopsy shows the typical histological features suggestive of pernicious anemia like atrophy of gastric mucosa of the body and fundus with inflammatory cell infiltrate, vitamin B12 deficiency cannot be proved. B12 deficiency does necessarily develop in all patients with these histologic features. Gastric biopsy would, however, help in investigating the possible causes of vitamin B12 deficiency.
→ Bone marrow biopsy (choice B) is not the correct choice. Bone marrow examination to demonstrate megaloblastic erythropoiesis is usually unnecessary. Even if performed, this examination will not distinguish B12 deficiency from folate deficiency.
→ Schilling test (choice D) is used to differentiate pernicious anemia from other causes of vitamin B12 deficiency. This test should be done only after vitamin B12 deficiency is established.
→ Like the Schilling test, serum parietal cell antibody (choice E) can be used to differentiate between pernicious anemia and other causes of vitamin B12 deficiency. This test, however, has a high degree of false positive results and can be positive in 16% of normal females over the age of 60. Thus, demonstration of parietal cell antibody does establish the diagnosis of vitamin B12 deficiency.
Key point: When vitamin B12 deficiency is suspected in an anemic patient or one with neurologic or psychiatric manifestations, the best investigation to rule it in or out is measurement of serum B12 level.
A 35-year-old man presents with swelling in the right scrotum. You notice a tender mass above the testis. The skin of his scrotum is red and inflamed. Elevation of the right hemiscrotum relieves the pain. He has pyuria.
What is the diagnosis?
Correct Answer A: Epididymitis presents with scrotal pain and swelling. Prehn's sign is positive (Prehn's sign, the physical lifting of the testicles relieves the pain of epididymitis but not pain caused by testicular torsion). Epididymitis is most common in young men ages 19 - 35. It is usually caused by the spread of a bacterial infection from the urethra or the bladder. The most common infections that cause this condition in young heterosexual men are gonorrhea and chlamydia. In children and older men, E. coli and similar infections are much more common. This is also true in homosexual men. Tests include U/A and Urine culture. Treatment is with antibiotics.
> Varicocele (choice B) is often asymptomatic , though patients may report scrotal pain or heaviness. A bag of worms is described on examination.
> Gonococcal urethritis (choice C) would present with dysuria and itching. The described Prehn's sign in this patient suggests epididymitis.
> Nephrolithiasis (choice D) causes lower abdominal pain that radiates to the groin. Tenderness in flank region can also be elicited on physical examination. The prehn's sign noted in this patient suggests epididymitis.
> Prostatitis (choice E) if symptomatic, it may cause urinary frequency, dysuria, and incomplete voiding. Digital rectal examination may reveal tender, nodular, hot, boggy, or normal-feeling gland. It may also reveal suprapubic abdominal tenderness. Prehn's sign noted in this patient suggests epididymitis.
A 45-year-old white male comes to your office with a 2-day history of pain and swelling in the right testicle. He has no dysuria or urinary frequency, and denies any sexual contact except with his wife. On examination you note tenderness in the right posterior aspect of the right testicle, along with some swelling and erythema of the overlying scrotal skin. Cremasteric reflex is normal.
Which one of the following is true regarding this situation?
Correct Answer E: Epididymitis is an inflammation of the epididymis due to various infectious agents or to local trauma. Pain may develop over a day or two, or even more gradually. In men under the age of 35 who are sexually active, the most common etiologic organisms are Chlamydia trachomatis and Neisseria gonorrhoeae. In men over 35, infectious epididymitis is usually nonspecific and is caused by coliform bacteria or Pseudomonas species. The preferred treatment is ofloxacin, 400 mg orally twice a day for 10 days. Alternative therapy is a single dose of ceftriaxone, 250 mg, plus doxycycline, 100 mg twice a day for 10 days.
A 20-year-old male presents with a complaint of pain in his right testis. The onset of pain has been gradual and has been associated with dysuria and urinary frequency. The patient has no medical problems and is sexually active. On examination he has some swelling and mild tenderness of the testis. The area posterior to the testis is swollen and very tender. He has a normal cremasteric reflex, and the pain improves with elevation of the testicle.
Which one of the following would be the most appropriate management of this patient?
Correct Answer C: This patient has epididymitis. In males 14-35 years of age, the most common causes are Neisseria gonorrhoeae and Chlamydia trachomatis. The recommended treatment in this age group is ceftriaxone, 250 mg intramuscularly, and doxycycline, 100 mg twice daily for 10 days. A single 1-g dose of azithromycin may be substituted for doxycycline. In those under age 14 or over age 35, the infection is usually caused by one of the common urinary tract pathogens, and levofloxacin, 500 mg once daily for 10 days, would be the appropriate treatment.
If there is concern about testicular torsion, urgent surgical evaluation and ultrasonography are appropriate.
Testicular torsion is most common between 12 and 18 years of age but can occur at any age. It usually presents with an acute onset of severe pain and typically does not have associated urinary symptoms. On examination there may be a high riding transversely oriented testis with an abnormal cremasteric reflex and pain with testicular evaluation. Color Doppler ultrasonography will show a normal-appearing testis with decreased blood flow.
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