Question 1
A 70-year-old fair-skinned Caucasian man presents to the hospital complaining of lesions on his scalp which he says feel like sandpaper.
His past medical history is not significant and he is a retired missionary who spent most of his life in Australia. On examination you note several scaly and erythematous papules on his scalp.
What is the most likely diagnosis?
A. Actinic keratosis B. Keratoacanthoma
C. Dysplastic nevus
D. Seborrheic keratosis
E. Discoid lupus erythematosus
Correct Answer A
The clinical presentation is suggestive of Actinic keratosis which are also known as solar keratosis. These lesions develop on skin which has been damaged by prolonged exposure to the sun’s ultraviolet (UV) rays on the scalp, face, lips and hands. AK are scaly, erythematous papules with a typical sandpaper texture when palpated. Biopsy of actinic keratosis lesions reveals atypical keratinocytes in the basal layer, hyperkeratosis or hyperplasia of the stratum corneum and parakeratosis which is the retention of the nuclei by keratinocytes in the stratum corneum together with solar elastosis.
If left untreated AK can evolve into squamous cell carcinoma (SCC). Treatment is with topical medications like 5-Flourouracil 5% cream and diclofenac sodium 3% gel. Cryotherapy with liquid nitrogen is also used to treat them.
Keratoacanthoma are dome shaped lesions with a central keratinous crater.
Dysplastic nevi or atypical moles are characterized by a variety of colors which range from pink to brown and the combination of macules and papules within one lesion giving them a "fried egg" appearance. Their borders are irregular and scalloped.
Seborrhoiec keratosis present as crusty plaques with a warty surface. Their borders are sharply demarcated and their bases non-erythematous. Seborrheic keratosis have a greasy, “pasted on the skin” appearance and their color ranges from white to brown-black.
Discoid lupus erythematosus is characterized by roundish plaques with scaling and sharply demarcated borders. The central area is atrophied and hypopigmented while the surrounding borders are hyperpigmented.
Question 2
A 55-year-old Caucasian woman presents to the hospital complaining of tingling sensations in her hands and feet for the past one month.
She is not on any medications and her past medical history is significant for one previous admission for a jejunoileal bypass. She is a married clerk who does not drink alcohol, smoke cigarettes or use illicit drugs.
What is the most likely diagnosis?
A. Celiac disease B. Whipple disease
C. Tropical sprue
D. Lactose intolerance
E. Short bowel syndrome
Correct Answer E
The clinical presentation is suggestive of Short bowel syndrome (SBS) which can be caused by surgical operations like the jejunoileal bypass, vascular accidents, diseases and any condition which causes a loss of more than 50% of the small intestines.
The resultant reduced absorptive surface area in SBS causes diarrhea, weight loss, pale greasy stools and other signs and symptoms of malabsoption. Nutrient deficiencies associated with SBS include Vitamin B12 deficiency which causes paraesthesias, fatigue and a megaloblastic anemia. Iron deficiency also causes fatigue and an anemia which is microcytic. Calcium malabsorption causes pain in the bones and carpopedal spasms. The treatment of short bowel syndrome treatment includes nutritional support and replacement of the deficient nutrients.
Lactose intolerance develops as a result of lactase deficiency which breakdown the lactose in milk into galactose and glucose. Symptoms of lactase intolerance develop after ingesting lactose containing foods and they include flatulence, borborygmi, nausea, abdominal cramps and loose stools. Laboratory investigations reveal that the diarrheal stools are acidic. Treatment includes following a lactose-free diet.
Celiac disease is a genetic disorder which is caused by intolerance to gluten which is found in wheat, barley, oats and other grains. Symptoms of gluten intolerance include abdominal distention with discomfort and diarrhea. Steatorrhea or pale, foul smelling stools which are difficult to flush are another symptom of celiac disease. Fatigue and weakness may also be present in patients who develop iron or folate deficiency. Bone pains are characteristic of calcium deficiency. The diagnosis of celiac disease is confirmed by taking a biopsy of the small intestines which shows a flat mucosa due to villous atrophy and subsequent improvement after treatment with a gluten-free diet.
Tropical sprue affects locals and tourists of tropical areas like the Caribbean islands and South India. Its cause is not known and it is associated with symptoms like diarrhea, weight loss and soft, bulky stools. Laboratory investigations done for patients suspected to have tropical sprue include stool microscopy for cysts and trophozoites. Treatment is with antibiotics like tetracycline.
Whipples disease is caused by Tropheryma whippelii and it affects the small intestines, joints, eyes, brain and other organs. Symptoms of this multisystemic disease include diarrhea, steatorrhea, weight loss and pains in the abdominal and joint. Biopsies of the small intestines are done and they reveal PAS positive foamy macrophages. Treatment is with antibiotics like trimethoprim-sulfamethoxazole or chloramphenicol.
Question 3
A 25-year-old African American woman presents to your clinic complaining of a painless swelling on her neck for half a year. This swelling does not affect her eating or breathing.
On examination you note that she has a tachycardia, hyperhidrosis and an anterior neck swelling which rises with deglutition.
What is the most likely cause of her condition?
A. Iodine deficiency B. Hashimoto’s disease
C. Thyroid cancer
D. Grave’s disease
E. Medications
Correct Answer D
The clinical picture is suggestive of a goiter which is basically an enlarged thyroid gland. It is characterized by an anterior neck swelling which rises with deglutition. The causes goiter are as follows: 1. Iodine deficiency develops when the body is unable to get enough of this mineral from the diet. Iodine is utilized by the body to produce the thyroid hormones triiodothyronine or T3 and thyroxine or T4. Deficiency of this mineral is the most common cause of goiter in the world. However, it is a rare cause of goiter in countries like the US which have iodized table salt.
2. Graves’ disease develops when thyroid stimulating immunoglobulin (TSI) is produced by the immune system. It stimulates the thyroid gland to produce hormones and the resultant excessive production of thyroid hormones makes it the most common cause of hyperthyroidism in the US. Other symptoms of this autoimmune disease that may be present in addition to the enlarged goiter include tachycardia, hyperhidrosis, weight loss, heat intolerance may also be present.
3. Hashimoto’s disease is the most common cause of hypothyroidism in the US. It is an autoimmune disease which arises when the immune system attacks the thyroid and causes inflammation. This results in hypothyroidism due to reduced production of T3 and T4. The pituitary gland attempts to increase the production of thyroid hormones by producing TSH or thyroid stimulating hormone and this results in thyroid enlargement. Signs and symptoms of hypothyroidism like fatigue, feeling weak, cold intolerance, constipation, dry skin and brittle nails may also be present.
4. Thyroid cancer is a relatively rare condition which usually presents as an enlargement of one side of the thyroid.
5. Medications which can cause goiters include lithium which is prescribed to treat bipolar disorder.
