Clinical Case 144: Man with a Mystery Malady

Today I have a tough clinical case for you.  One that crosses from GP to ED and into internal Med.  This is not core GP stuff but does highlight some diagnostic strategies that we all need to keep in our armoury.

A 65-year-old man presents to the ED with a 3-week history of profuse diarrhoea (watery), he has developed a widespread maculopapular rash in the last week and is feeling confused at times.  His wife reports that he is usually quite sharp, but has been cognitively slow and forgetful.  There has been some sweats and fevers at nights.  He tells you that tHe has also noted increasing lumbar back pain and this is on a background of chronic lower back pain that he tolerates.  He has lost between 10 – 12 kg (22 – 25 lbs), though he thinks this is mostly that he feels nauseous and cannot eat more than a few mouthfuls at a time.

He has not taken any of the medications prescribed in the last week as he feels sick and worried they will make him worse

No recent travel or other infectious exposure noted.  No sick contacts


  • Hypertension treated with ramipril 5 mg/day
  • Prostatism – had a biopsy showing benign disease
  • Gout – had 2 episodes of knee flare in the last year – commenced on allopurinol 1 month ago
    • he was taking colchicine as preventative around the commencement of allopurinol – ceased 3 weeks ago
  • Sebaceous cyst to the scalp – excised a month prior and had a course of oral cephalexin for a minor infection
  • Thalassemia minor
  • ex-smoker – 30 pk years, quit 10 years ago
  • Drinks 1 – 2 beers on 3 or 4 days a week
  • No allergies

On examination:

Looks a little dry on the lips and unwell.  Observations: HR 90 SR,  BP 110/70 with a small postural drop,  RR 14  SpO2 97%.   He is febrile at 38.3

The neurological exam is normal aside from a fine resting tremor. No loss of leg reflexes or power

The chest is clear.  ENT exam is normal

The cardiovascular exam is NAD

The abdomen is maybe a little distended, tender all over but with no focal peritonism.

There is no evidence of hepatosplenomegaly or any enlarged LN in the axilla, neck or groin.

Skin – rash is diffuse maculopapular blanching spots.  Looks a bit like roseola if he were 65 years younger!  The scalp wound is healed nicely and no sign of infection.

His back is not tender to palpation, he has limited forward flexion and pain on straight leg raise

Urinalysis shows blood 2+, Leuks tr no nitrites  & protein 3+

So he has some blood drawn and an IV sited.

When asked what is the worst part of this illness:

  1. the diarrhoea is constant and causing incontinence
  2. The back pain is keeping him up all night.

Bloods are back – there are a lot…  the important ones are:

  • FBP:  WCC up at 16, with a raised neutrophil and eosinophil count (12 and 2.6).  Normal Hb
  • Renal impairment – creatinine 260 with eGFR about 20.  Previously had Cr of 110 at worst
  • LFTs show hepatitis:  ALP 160, ALT 330, GT 660, bilirubin 60, albumin 25, raised total protein,
  • CRP (yes, one was done, I know..)  is 190!
  • He has blood cultures drawn and urine plus a stool is sent…

A CXR is essentially normal, no consolidation, lymphadenopathy or effusion.

OK, that is all the data you have at the moment…


(1)  What are your 3 main diagnostic concerns – probability, scary and unifying Dx?

(2) What tests do you need next?

(3) What if any empirical treatment would you commence?




  1. Infective colitis, campylibacter gastroenteritis, cholangitis
    Stool samples, ct abdo and lumbar, blood gas
    Azithro for campylo and tazocin broad spectrum

  2. Infectious cause with new infection such as hiv with ongoing diarhoea. Legionella give liver. Back. Diarrhoea.
    Cmv liver diarrhoea.
    Japanese encephalitis.
    Anything infective linked with liver and pancreas

    Cancer such as one of the myelomas.

    Structures such as discitis

    Wcc screen
    Hiv. Hepatitis. Cmv. Japanese encephalitis.
    Consider faecal amoebes

  3. No one has allopurinol hypersensitivity syndrome on their DDx? Classic presentation—delayed vs. immediate onset, protracted course, preexisting renal impairment, fever, rash, eosinophilia+hepatitis, nonbloody diarrhoea…

  4. Simon Baylis says

    I suspect this guy has DRESS syndrome with Allopurinol as the likely precipitant.

    Helminth infection

    TTE for ? Myocardial involvement
    Skin biopsy

    Stop Allopurinol
    Discuss with Dermatology regarding steroids

  5. Strep bacteraemia with emboli and abcesses to back, liver and kidneys.
    IV fluclox and Vanc and gent

  6. Congrats to Simon Baylis who is the super sleuth of the month
    Idiosyncratic drug reactions are scary

  7. PasoepatiNet says

    Thank you so much! I will check it out for sure:)

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