19. Constipation

Question 1

What 4 main categories can you classify causes of constipation into ?

Answer 1

Abnormal peristalsis
Hard faeces
Bowel obstruction
Patient not pushing

Question 2

What can cause abnormal peristalsis?

Answer 2

IBS

Medications: opiates, iron, CCB’s

Question 3

What can cause hard faeces?

Answer 3

Lack of fibre

Dehydration

Question 4

What can cause bowel obstruction?

Answer 4

Colorectal adenocarcinoma

Sigmoid volvulus

Question 5

What can cause the patient to avoid pushing when they go to the toilet?

Answer 5

Haemorrhoids
Anal fissues
Pelvic floor dysfunction

Question 6

What are 6 red flags from constipation?

Answer 6

Severe persistent constipation unresponsive to treatment
Absolute constipation with no gas passing
Rectal bleeding, tenesmus, mucoid diarrhoea
FLAWS
PMHx UC/ Polyps
FHx polyps/ cancer

Question 7

What associated symtpoms should you ask about in someone with constipation?

Answer 7

Diarrhoea (IBS, Colorectal cancer, diverticular disease)
Tenesmus (mass)
Blood (haemorrhoids, fissure, diverticular disease)
Bloating (IBS)
Hypothyoidism symptoms
Bone pains
Polyuria

Question 8

What may polyuria and bone pain suggest in someone with constipation?

Answer 8

Hypercalcemia due to bone mets.

Question 9

What are risk factors for constipation?

Answer 9

Hx of bowel disease, endo/ neuro disease, back problems
FHx of bowel disorders
Medications
Poor diet

Question 10

In what neurological conditions may patients have constipation as well?

Answer 10

Diabetic neuropathy
Multiple sclerosis
Cord compression
Parkinsonism

Question 11

What blood tests may be relevant in someone with constipation?

Answer 11

FBC: colonic mass can cause anaemia
Electrolytes + calcium
TFTs

Question 12

What are markers for colon cancer?

Answer 12

CEA
Ca 19-9
Ca 125 (more ovarian cancer)

Question 13

What is suggested by lax anal tone?

Answer 13

Neurological pathology e.g. diabetic neuropathy or MS

Question 14

What is the biochemistry in a patient with bone metastases? Why?

Answer 14

ALP: High
PTH: Low
Phosphate: High
Increased bone turnover

Question 15

What is the biochemistry in a patient with myeloma? Why?

Answer 15

ALP: Normal
PTH: Low
Phosphate: High
Osteoclasts activated, osteoblasts inhibited (so ALP norm)

Question 16

What is the biochemistry in a patient with primary/ tertiary hyperparathyroidism? Why?

Answer 16

ALP: Normal/ High
PTH: Normal/ High
Phosphate: Low
PTH increases bone turnover, PTH increases renal excretion of phosphate. No negative feedback on PTH

Question 17

What is the biochemistry in a patient with vitamin D overdose? Why?

Answer 17

ALP: Low
PTH: Low
Phosphate: High
Increased gut absorption of calcium + phosphate. 
No increase in bone turnover
PTH suppressed

Question 18

What is the TNM classification?

Answer 18

Tumour size: 1-4
Nodes: 0 (none)- 3 (many + distant)
Mets: 0 (none) or 1 (present)

Question 19

Describe the Dukes Classification of colon cancer

Answer 19

A: No spread into muscularis propria
B: Tumour invading beyond muscularis propria
C: Tumour spread to lymph nodes
D: Tumour metastasised to other organs