A 66 year old woman presents with a history of weight loss - Case Study

History
A 66-year-old woman, a retired nurse, consults her general practitioner (GP) with a 4-month history of tiredness, slight breathlessness on exertion and loss of weight from 71 to 65 kg. Her appetite is unchanged and normal; she has no nausea or vomiting, but over the last 2 months she has had an altered bowel habit with constipation alternating with her usual and normal pattern. She has not seen any blood in her feces and has had no abdominal pain. She has had no post-menopausal bleeding. There is no relevant past or family history, and she is on no medication.
She has smoked 20 cigarettes daily for 48 years and drinks 20–28 units of alcohol a week.

Examination
She has slight pallor but otherwise looks well. No lymphadenopathy is detected, and her breasts, thyroid, heart, chest and abdomen, including rectal examination, are all normal.
The blood pressure is 148/90 mmHg.

Investigations: 

• Haemoglobin = 10.1 g/dL (normal = 11.7–15.7 g/dL)
• Mean corpuscular volume (MCV) = 76 fL (normal = 80–99 fL)
• White cell count = 4.9 × 109/L (normal = 3.5–11.0 × 109/L)
• Platelets = 277 × 109/L  (normal = 150–440 × 109/L)
• Sodium = 142 mmol/L  (normal = 135–145 mmol/L)
• Potassium = 4.4 mmol/L  (normal = 3.5–5.0 mmol/L)
• Urea  = 5.2 mmol/L  (normal = 2.5–6.7 mmol/L)
• Creatinine = 106 μmol/L  (normal = 70–120 μmol/L)
• Urinalysis: no protein, no blood
• Blood film shows a microcytic hypochromic picture.

Questions

• What is the most likely diagnosis?

• How would you investigate the patient?

Case Discussion:

The investigations show a microcytic, hypochromic anaemia. In a premenopausal woman the most likely cause would be excessive menstrual blood loss. In men or postmenopausal women the most likely cause would be loss from the gastrointestinal tract. This woman has an altered bowel habit, which suggests a problem with the lower gastrointestinal tract and a diagnosis of carcinoma of the colon, which would also explain her weight loss. 

Carcinoma of the colon is increasing in frequency. If it presents at an early stage, then the prospect for cure is good. Rectal bleeding, alteration in bowel habit for longer than 1 month at any age, or iron-deficient anaemia in men or postmenopausal women are indications for investigation of the gastrointestinal tract. In younger people there may be a hereditary element

to carcinoma of the colon.

Smoking is a risk factor for carcinoma of the colon.

Followup of the patient in this case: 

A barium enema revealed a neoplasm in the sigmoid colon, confirmed by colonoscopy and biopsy. Chest X-ray and abdominal ultrasound showed no pulmonary metastases and no intra-abdominal

lymphadenopathy or hepatic metastases, respectively.

She proceeded to a sigmoid colectomy and end-to-end anastomosis and was regularly followed- up for any evidence of recurrence. Histology showed a grade I tumor.

Key Learning Points:

• Carcinoma of the colon can present with few or no symptoms or signs in the gastrointestinal tract.

• Unexplained iron deficiency anemia warrants investigation of the upper and lower gastrointestinal tract.